Lepidoptera Survey Methods Utilized in North American Journal of Lepidoptera Biodiversity Publications.
Hugo L. Kons Jr. & Robert J. Borth
Note: This reference is solely a web based publication which is subject to future modifications and updating, as opposed to a static formal scientific paper.
This web page is a supplement to the
materials and methods section of North American Journal of Lepidoptera
Biodiversity publications reporting survey results from Kons and Borth
Lepidoptera surveys. It also can serve as a supplement to methods
sections of scientific collecting permit applications. NAJLB volume 1
provides case studies of the effectiveness and relative effectiveness of
different survey techniques for documenting adult Macrolepidoptera species
Illuminating a white sheet with mercury vapor and ultraviolet lights and hand collecting representative specimens which fly in to the sheet with jars is the most effective survey method for documenting adult Macrolepidoptera species diversity. Staying up all night collecting at a sheet can dramatically improve one's results. We have found on warm nights the interval from about -just before sunrise frequently yields the greatest variety of species. We power AC lights at sheets with a small Honda EU1000i generator. We discuss DC lights under UV traps, below.
[Add Photo of Kons Sheet Stand]
MV/UV Sheet Stand: This is the assembled structure for putting up a king sized white sheet with plastic pipes, designed by Hugo Kons Jr. An advantage of this design is that it provides more surface area for moths to land on the sheet relative to the previous design. However, it has the disadvantages of being more vulnerable to wind damage (due to the larger surface area of sheet) and requiring more pipe length and thus more space in a vehicle. This structure is not commercially available.
MV Light Stand. Photo Copyright Robert J. Borth 2006.
The grey section in the middle of the above photo is the bottom of the MV light stand. This section is hollow, and is placed over the stake on the left side of the picture. The Blue section which supports the light is screwed into the top of the grey section.
Shepherd Hook Used as a MV Light Stand: American Entomological Institute
UV light traps are very important for Lepidoptera surveys, as they allow one to collect all night without being present, enable one to survey multiple habitat types and/or locations on a single night (with multiple traps), enable surveys in locations where utilizing a sheet would be difficult or unfeasible, and enable surveys under conditions when it is not possible to run a sheet (such as high wind). In addition, UV traps are very useful for quantitative sampling if one has the opportunity to collect in an area repeatedly. However, on any given night actively collecting all night at an individual MV or UV sheet will yield a species total considerably higher than an individual UV trap, providing the habitat is similar. The combination of a sheet and several light traps is ideal for doing surveys, especially when the UV traps can be placed in different types of habitats from where the sheet is located.
Where AC power is unavailable, UV traps can be operated with DC UV lights powered by deep cycle outboard batteries. The 15 watt DC UV lights we use in our surveys were purchased from BioQuip Products. These lights are very durable including under adverse weather conditions such as high wind and heavy rain. We power our UV lights with deep cycle outboard batteries, which reportedly are more resistant to being run all the way down relative to regular batteries. A 34 amp hour battery will run a UV trap at least one night when it is new, and is fairly easy to carry long distances away from a vehicle. When Kons was doing surveys in WI during the early to mid 90s, he found that a new 34 amp hour outboard battery purchased from Fleet Farm would run a UV trap 3 nights, but in recent years we have been finding batteries of this size only tend to run a 15 watt UV light for one full night and part of a second when they are new. Walmart no longer carries 34 amp hour outboard batteries, but they can still be purchased from Fleet Farm. The larger outboard batteries are essential for multinight collecting trips without access to AC power for battery recharging. Deep cycle batteries of various sizes larger than 34 amp hours can be purchased at Walmart or Fleet Farm, and doubtlessly numerous other stores. The disadvantage of these batteries is that they are quite heavy, and difficult to carry long distances from a vehicle, especially under hot conditions or over rugged terrain.
When a UV trap is placed too far
away to be easily turned off at dawn, one can conserve battery power by
purchasing DC photo cells from BioQuip Products. The photocells should
not be used on traps located close enough to be easily turned off manually
at dawn, because they use more power than just running the UV light by itself
for the time they are on, and they are not as durable or reliable as the
DC UV lights. Photocells will frequently stop working and shut the UV
light off if they are exposed to moisture such as rain, and sometimes this
happens even under dry conditions. When the photocells are exposed
to moisture and stop working, if they are dried out they usually will start
working again. We have got around the rain problem by placing the photo
cells in quart sized zip loc bags, and orienting the bags in such a manner
that rain will not get in. When AC power is available, one may
purchase an AC photocell from Walmart much more cheaply than a DC photocell
from BioQuip. Also, Kons has been using an AC photocell
purchased from Walmart at the AEI property in northern
When AC power is available there are more options to choose from for what light to use in a UV trap. At the AEI property in northern Florida, Kons has been using a 33 watt BL UV light manufactured from General Electric (product number 47912), and this light holds up well under the rainy, humid Florida conditions, despite the product containing a warning to avoid moisture. However, this light is problematic for sheet set ups, because it can easily detach from its chord and fall to the ground and break, whereas in the trap it rarely becomes detached and when it does the short distance it falls does not damage the light. BioQuip Products sells a 15 watt AC UV light comparable to the DC version, which is very durable under field conditions, and which cannot become detached from the electrical chord.
Trap (Front) with 33 watt BLB AC UV Light.
American Entomological Institute:
The trap frame was constructed by Hugo L. Kons Sr., based on a design by Hugo Kons Jr. The frame consists of a sawed off tractor fueling funnel bolted to a metal pipe, which forms a half circle around the rim of the funnel. At the top, a wooden piece is bolted between the sides of the pipe, and a metal kook is screwed into the top center of this wooden bar. The trap is suspended from tree branches with the metal hook. If branches are too thick for the metal hook, we clip shower rings onto the branch and attach the hook to the shower ring. The trap frame design represents a modification of a design previously published in [FILL IN INFO].
Trap Frame (Front View): Southwest Corner of Highways I10 and 279,
Trap Frame (Lateral View): Southwest Corner of Highways I10 and 279,
Trap Frame (Back View):
UV Trap Collection Container (Open). Photo Copyright David B. Wahl 2006.
Inside of UV Trap Collection Container with Components Removed. Photo Copyright David B. Wahl 2006.
The UV trap container is constructed
from a 2 gallon circular Rubbermaid container. This container is attached
to the trap frame with two bungee chords which hook over the lip of the tractor
fueling funnel on the sides where it connects to the metal pipe. The
bottom of the sawed off tractor fueling funnel fits into a hole in the cover of
the Rubbermaid container (illustrated below). The plastic square piece in
the center serves as an extremely reliable rain drain, which keeps the trap
catch dry (excluding small specimens which get through the mesh into the rain
drain, or specimens which die on top of the rain drain) even under 40-60 mile
per hour winds and heavy rain associated with tropical storms. The rain
drain container fits through a square hole in the bottom of the trap.
This hole was covered with duct tape on both sides and then an X was cut
through the duct tape between the four corners. When the rain drain is
inserted through the X in the duct tape, a seal is formed eliminating the
possibility of specimens falling out of the trap between the bottom of the
rubbermaid container and the rain drain. A fine net mesh is attached over
the top of the rain drain with a rubber band. Most Macrolepidoptera
specimens will not get through this mesh into the rain drain, but some
microlepidoptera and some of the smallest Macrolepidoptera specimens may
go through the mesh and into the rain drain. The bottom of the rain drain
(under the paper towels) has four holes in the plastic container where water
drains out. The bottom surfaces of the trap and rain drain are covered
with soft, thick paper towels (we use the Viva brand). The red and white
circular containers adjacent to the Saturniid Antheraea polyphemus
are the ethyl acetate wicks. Unfortunately, Rubbermaid appears to have
discontinued this type of plastic container, and the new model is wider on the
top and thus not suitable for a trap of these dimensions. The wicks are
filled with ethyl acetate when the trap is put up. This chemical may be
purchased from BioQuip Products by anyone. It is less expensive if
purchased from Fischer Scientific, but this discounted rate can only be
obtained through the account of an educational institution. The wicks are
placed in wick holders made from two rings of duct tape (the sticky sides of
the tape are stuck together and not exposed), which are duct taped to the side
of the trap. This ensures that the wicks will never turn over unless the
trap is tilted over 90 degrees (tilting the trap container should be
minimized to prevent specimens from sliding on the paper towels and loosing
scales). Care must be taken to ensure that no paper towels are in contact
with the wick material or the top of the rain drain. Otherwise, ethyl
acetate or water, respectively, will wick throughout all of the paper towels in
the trap. The illustrated trap catch is from
A downside to this design is that the trap container cannot be placed on a flat surface without popping the rain drain container out of place. When the rain drain is popped out, specimens may fall out of the trap through the square hole in the bottom. This problem is eliminated by setting the trap on any container with an opening wide enough and deep enough to accommodate the rain drain. The below picture shows the trap container sitting on an open minnow trap. An alternative strategy would be to glue legs on the bottom of the trap container long enough to accommodate the length of the rain drain.
UV Trap Collection Container (Closed) Sitting on Top of a Minnow Trap. Photo Copyright David B. Wahl 2006.
This picture illustrates the same trap container in the preceding picture, but shows the top cover in place. The metal minnow trap container below the plastic cylinder is not part of the trap container, but only used as a stand to prevent the rain drain from popping out of place. The circular hole in the cover is where the bottom of the tractor fueling funnel is inserted into the plastic trap container. This hole was covered with duct tape on both sides (such that no sticky side of the duct tape is exposed) and a X was cut through the center of the duct tape. This forms a better seal between the trap frame and the trap container, reducing ethyl acetate evaporation to the outside.
Baiting involves attracting individuals
of certain species of Lepidoptera to fermenting fruit baits. The variety
of species attracted to these baits is much less than the variety which may be
attracted to lights, but there are a number of Lepidoptera species which come
much more readily to rotting fruit baits than to lights. When bait is
working well, the use of bait trails and/or traps can add considerably to
recorded species totals. For reasons we largely do not understand, the
success of baiting is extremely variable spatially and temporally. NAJLB
Volume I provides case studies of the effectiveness of
baiting at documenting Macrolepidoptera species diversity in northern
Baiting surveys can be performed with bait traps or bait trails. We have used a variety of different types of bait traps, which we illustrate and discuss below. Bait trails consist of bait placed on tree trunks or strips of felt suspended from nylon twine (=felt lines). Both bait trails and bait traps have some advantages, so ideally surveys with bait will involve the use of both. However, not all survey sites have a lot of easily accessible tree trunks suitable for baiting trees or putting up felt lines, and on short collecting trips time can be too limited to utilize both techniques. A discussion of some of the relative advantages of the two techniques follows.
Advantages of bait traps relative to bait trails:
* Bait traps may attract a variety of Lepidoptera even when bait trails are ineffective. This is probably due to the larger volume and concentration of bait that is used in bait traps. If one is surveying in an area and finds bait trails are adding little to species totals, it should NOT be assumed that this will be the case with bait traps.
* Bait traps allow one to conduct surveys at times they are not physically present at the site. For example, one cannot be watching a sheet and checking a bait trail at the same time.
* Bait traps may be used in a variety of areas where finding suitable spots for bait trails is problematic. Baiting trees requires easily accessible tree trunks, whereas this is not important for bait traps.
* Much more skill is required to effectively survey Lepidoptera from a bait trail, with respect to seeing Lepidoptera camouflaged on their substrate (such as a tree trunk) and with respect to capturing voucher specimens.
Advantages of bait trails/felt lines:
* Bait trails enable one to bait a much larger area.
* Bait traps are expensive or time consuming to custom make, and they are susceptible to vandalism by humans or damage by animals such as raccoons or bears. In contrast, besides the bait a bait trail requires only a paint brush and a bait container, or in the case of a felt line one needs only nylon twine, felt, clothes pins, and a bait container.
* At times when bait is attracting large numbers of Lepidoptera, bait traps may become very cluttered. This may make it difficult to pick out all of the species present among large numbers of individuals of common species, and/or result in some desired specimens becoming worn.
* Bait may also attract stinging insects, such as Vespids, Pompilids, and fire ants, making it difficult to collect out of bait traps without risking getting stung. Bald faced hornets can be especially problematic, because of their aggression and painful sting. Also, some species of vespids may prey upon Lepidoptera specimens in a bait trap.
* Running multiple bait traps requires one to purchase and transport much more bait than is required to put up bait trails.
* Painting bait on tree trunks may require less time than other methods, particularly when baiting is conducted well away from a vehicle. One does not need to pick up traps or conduct any clean up (banana bait on tree trunks does not persist in the environment for very long).
* The ideal time to check bait traps is right after sunrise, as specimens may beat up their wings when the sun shines on the traps, especially if there are many specimens in a trap. Unfortunately, right after sunrise is also the most comfortable time of the day to sleep when one has stayed up all night collecting. This is also a time when mosquitoes can be especially voracious when one is standing relatively still and checking a bait trap.
The bait trap has become an indispensable tool for conducting our Lepidoptera surveys, and has been the subject of much experimentation. We provide a brief chronological history of our trap usage followed by a more detailed explanation and illustrations of the various trap designs.
1979 – Inverted Cone Platform Bait Trap
RJB began using this trap
design, which had originally been illustrated by Austin Platt in the Journal of
the Lepidopterists’ Society in 1969, to collect tropical Lepidoptera in
1988 – Minnow Trap (Type F Trap)
HLK began raising baited
minnow traps into canopy overhangs at various
1989 – Inverted Cone Platform
Bait Trap/Minnow Trap Usage in
RJB used both these traps in
the canopy every day for a month in
1990 – Modified Inverted Cone Platform Bait Trap (Type P Trap)
HLK received a more effective type of inverted cone trap with a larger opening from Richard Merkhofer. HLK slightly modified the design of this trap to make the cone lower, improving effectiveness somewhat. These traps were built by Sharon Kons, and proved considerably more effective than the original inverted cone trap design; however, there were some problems with escape.
2002 – Inverted Cone No Platform Trap (Type NP Trap)
HLK modified some type P traps
by replacing the platform with a plastic container with entrance slits that
attached to the bottom of the hole in the inverted cone. This design
often outperformed the platform inverted cone traps where the two designs were
run in close proximity at the American Entomological Institute property in
2002 –Koehn Bait Traps (Type K Traps)
RJB purchased a couple traps from Leptraps, Inc. These traps, designed by Leroy Koehn, added a new platform bottom with an 8 ½” pie tin bait holder to the bottom of the standard 36” high, 15” diameter cylinder. The inverted funnel was eliminated as insects would enter from a one inch gap between the aluminum pie tin and flat plywood ring bottom. These traps were sturdy but somewhat heavy, and they took longer to set up in the field. On our first collecting trip using both Koehn traps and NP traps we did not note a significant difference in performance between the two.
2004 – 2 Gallon Rubbermaid Plastic Containers Used for Bait
In the Spring
of 2004 we traveled to the
2006 - Our Current Cylinder Trap with Plastic Container Bottom (Type H trap)
HLK eliminated the heavy platform bottom
from the Koehn trap and instead dropped the two gallon plastic container into a
flat circular plywood ring bottom. Slits at the top allow entrance but
virtually no escape. These traps have often been very effective with a
large bait volume, and we have found they outperform all of the other types of
bait traps. In addition, they are simpler to construct, light, sturdy,
and quite escape resistant. RJB built some traps with an extra wooden
ring around the plastic container so Lepidopterans
would have a shelf to land on, but we have not noted any difference in
effectiveness between traps with this extra ring and those without it. We ran up to ten and eleven of these traps in
HLK has frequently placed two identical bait traps right next to each other with different types of bait, to gain insight into what baits are most effective. As a result, we primarily bait our traps with rotten bananas, but sometimes also use rotten plantains and rotten applesauce. Rotten bananas and plantains are most effective when the fruit is at the stage of rot where it is a yellow mush. It is possible plantains may be somewhat more attractive than bananas when they are at this stage, but a downside to plantains is that they are more expensive, available at fewer stores, and the rotting process takes much longer to achieve the optimal stage of rot. Rotting Applesauce is a good bait for felt lines (below) and it is not clear if it may improve effectiveness in some cases if used in addition to rotten bananas in traps. However, it can dry out quickly in bait traps, and also sometimes some Lepidoptera individuals become stuck in the applesauce if a large quantity is used. HLK has found no indication that adding brown sugar to solid baits in bait traps improves bait effectiveness. HLK has tried all of the liquid baits mentioned below (in the section on relative effectiveness of baits for bait trails) and found none of them work as well as rotten bananas, and they all are problematic with respect to Lepidoptera drowning in the liquid. Rotten bananas have consistently outperformed rotten apples, rotten pears, rotten peaches, and rotten grapes.
Bait Trap Designs
Cloth Cylinder Bait Traps: We have used four designs of cylinder traps which we illustrate and discuss below. All of these trap designs contain a zipper on the side, which is unzipped to collect desired specimens. One note that applies to all cylinder traps is we do not recommend collecting nocturnal species out of these traps at night if it can be avoided, as in our experience this increases the chance desired specimens will escape. Lepidoptera individuals almost never escape from type NP or type H bait traps before they are opened. The best time to collect nocturnal species from these traps is right after sunrise during the coolest part of the day and before the sun starts shining. Once the sun shines on a trap, Lepidoptera are more active and more difficult to collect, and specimens might become worn if the trap is very crowded. On the other hand, in the very early morning when it is still somewhat dark (dusk like conditions), on warm nights Lepidoptera may be very active at this time, so the optimal window to check the traps can be rather small. Checking traps in the early morning is less important for traps which are placed in shaded locations or which are not crowded with many specimens.
H Bait Trap:
H Bait Trap Close-Up: American Entomological Institute:
Type H Bait Trap (Bottom). Photo Copyright David B. Wahl 2006.
Type H Bait Trap (Inner Bottom). Photo Copyright David B. Wahl 2006.
Bottom of Type H Bait Trap with Bait Container Removed. Photo Copyright David B. Wahl 2006.
Type H Bait Trap: This is our most recent and most effective bait trap design, which we began using in 2006. The illustrated bait trap was constructed by Sharon Kons and designed by Hugo Kons Jr. The plastic container in the bottom was modified by Danny McFather according to HLK's specifications. The components include a cloth cylinder with a circular wooden bottom with a large circular hole. This hole is the right size for fitting in a Rubbermaid 2 gallon circular plastic container. The plastic container contains slits near the top, whereby Lepidoptera enter the trap to access the bait placed at the bottom of this container, but very rarely escape until they are released deliberately by removing the bottom. Specimens which are not collected may be easily released by removing the plastic container and wooden circular platform from the bottom of the trap, and then shaking the trap out.
Bait Trap (Type K Bait Trap):
Bottom Section of a Koehn Bait Trap. Photo Copyright Robert J. Borth 2006.
Top of a Koehn Bait Trap After a Collecting Night:
Koehn Bait Traps: This bait trap was purchased from and designed by Leroy Koehn. The trap consists of a cloth cylinder with a large hole in the bottom. The cylinder is attached to a wooden platform with four eye hooks, and bait is placed in an aluminum pie tin on the platform under the hole in the bottom of the cylinder. This bait trap design tends to be the second most effective among the bait trap designs we have utilized, with only the type H design tending to be more effective. However, the type H trap design needs to be custom built and is not commercially available, whereas Koehn bait traps can be purchased directly from Leroy Koehn. Compared to the type H trap design, Koehn traps are heavier on account of the solid wooden platform, and they are more difficult to set up. There are more problems with escapees from Koehn traps relative to other bait trap designs; however, with the exception of the type H trap this difference is often more than compensated for by trapping more individuals in the first place. Releasing specimens from Koehn traps is slightly more time consuming than type H traps, but much quicker than with inverted cone cloth cylinder traps (type P and type NP traps).
NP Bait Trap: American Entomological Institute Property,
Type NP Trap Bait Container. Photo Copyright David B. Wahl 2006.
Inverted Cone Bait Trap with No Platform (Type NP Bait Trap): A type NP bait trap is identical to a type P bait trap (below) except that the platform is removed, and the container housing bait attaches to the opening in the inverted cone. Bait is placed in the bottom of this container, and moths enter through slits in the side. This concept is similar to the type H trap, and was a precursor to the type H design. Kons began using this trap design in 2002, after learning it reduced escapes to essentially nil (in contrast to the type P trap) and averaged more moths than a type P trap. The bait container was constructed from two components, the top which was selected to fit into the opening in the inverted cone, and the bottom which was selected to be deep enough as to hang below the level of the inverted cone when the trap was suspended. This trap design does have several disadvantages. One is that the trap container is an awkward size and shape, and storage of this container is problematic for collecting trips where space is at a premium. The other disadvantage is that the bait container has limited volume, and only a couple rotten bananas can be used at one time without covering the entrance slits. These disadvantages were eliminated with the type H bait trap design, which eliminated the cone altogether and allowed for a wider but shallower container that can hold a much larger volume of bait.
Inverted Cone Platform (Type P) Bait Trap. Photo Copyright David B. Wahl 2006. The bait container is not shown. It is placed on the wooden platform directly under the cone.
Type P Bait Trap with Plastic Bait Container of Appropriate Dimensions. Photo Copyright David B. Wahl 2006.
Bottom of Type P Bait Trap (the platform has been removed and the trap is being held upside down to show the cone). Photo Copyright David B. Wahl 2006.
Inverted Cone Bait Trap (Type P Bait Trap): A type P bait trap involves placing a dish of bait on a platform underneath an inverted cone with an opening. The illustrated example is based on a slightly modified design from a trap Kons received from Richard Merkhofer. The traps of this design used in the Kons-Borth surveys were custom built by Sharon Kons, and are not commercially available. This design works considerably better than some commercially available inverted cone bait traps with higher cones and a smaller opening above the inverted cone. The inverted cone opens into a cloth cylinder. The platform is attached to the cloth cylinder with only a narrow 360 degree opening between the cylinder and platform. Lepidoptera travel through this opening to feed at the bait dish. When done feeding, some individuals fly up through the open inverted cone and become trapped, whereas others leave through the side the way they entered. Based on many nights of running this type of trap in the same areas with type H, type NP, and/or type K bait traps, it is clear that this trap design tends to yield fewer Lepidoptera relative to these other designs. A major disadvantage is many of the Lepidoptera that come to feed at this type of trap leave out of the opening between the cylinder and the platform, and never fly up through the inverted cone and become trapped. This performance factor is also influenced by the type of bait container used on the platform-a container with higher sides tends to increase the likelihood that individual Lepidopterans will become caught in the trap. Another disadvantage is that escapes are not uncommon with this trap design, when Lepidopterans fly back out of the opening of the inverted cone and escape out of the side (escapes are less common than with a Koehn trap, but a Koehn trap tends to trap more individuals in the first place). Type P traps are light weight, and can be put up quickly and easily in the field. Cool Whip containers or any number of similar plastic containers work good as bait dishes.
F Bait Trap (Lateral View): American Entomological Institute Property,
F Bait Trap (Oblique Side View): American Entomological Institute Property,
Type F Bait Traps: This trap design consists of a commercially available minnow trap used as a bait trap for Lepidoptera. Kons came up with this idea in 1988 in WI. The mesh in the minnow traps is fine enough to trap Lepidoptera species in genera such as Catocala and Zale, but for many of the smaller Noctuids a finer mesh must be sown around the trap to prevent individuals from escaping out of the holes in the mesh (the illustrated example includes this modification, done by Sharon Kons). Each side of the trap contains an inverted cone with a small opening, and bait is placed in a cool whip or other plastic container inside of the trap. The trap is opened by splitting it into two halves, which are reassembled with a clip. This trap is light weight and very easy to put up in the field within normal reach. However, some of the best successes with this trap have involved placing it in a canopy overhang. This is accomplished by throwing a roll of nylon twine over a canopy overhang, and attaching one end of the twine to the clip. One can then pull on the other end of the twine and raise the trap up to be nestled into the canopy overhang. Caution must be used when applying this technique to pine trees, as we have had some problems with sap permeating the nylon twine and leaving the trap stuck in the canopy. Releasing specimens which are not collected from this trap is extremely easy, as one needs only to open the two halves and shake them out.
This trap design can be very effective, especially in canopy overhangs for the genus Catocala. On many occasions Kons has found these traps loaded with Catocala in WI, where they often trapped more individuals and species than Type P traps in the same vicinity. All but one of Kons' records for Catocala luciana in WI were obtained with this type of trap in a canopy overhang.
However, this trap design has two very significant disadvantages. One is the trap can quickly become too crowded with individuals of larger species (such as Catocala, Darapsa, Amphion, Nymphalis, Polygonia, Vanessa, Astereocampa, etc.) resulting in many individuals flying around and beating up their wings. These traps must be checked and emptied frequently when bait is working well to obtain specimens in good condition. The cloth cylinder traps will hold larger numbers of individuals in good condition for a longer period of time. The other major disadvantage is collecting specimens out of these traps is much more difficult than with any of the cloth cylinder designs. The best technique is to open the trap at night right next to a MV sheet. Most nocturnal and diurnal species in the trap will fly right to the sheet, including species in the area which are coming readily to bait while largely ignoring the sheet otherwise. However, with this approach some desired individuals may leave the sheet before they can be collected. This approach is also problematic for studies where one desires quantitative data on the number of species coming to the sheet and bait trap individually, as it is easy to become confused as to whether some individuals originated from the bait trap or the sheet. When these traps are opened during the day, one approach is to first place them inside of a cooler with ice before attempting to open them. Obviously such an approach is inefficient in terms of time and space. Alternatively, the traps can be opened inside of a net large enough to hold the entire trap.
Bait Trails/Felt Lines: Bait trails/felt lines involve placing bait on trees or felt strips and later searching for Lepidoptera in the baited areas. For reasons discussed below, we recommend a paste-like bait of mashed rotten bananas and brown sugar for bait trails on trees, and either this same bait and/or rotten applesauce mixed with brown sugar for felt strips. For nocturnal collecting, a net is often unnecessary and just gets in the way, but it may be essential for some especially wary species like Catocala delilah and some of the other larger Catocala. In general, a good sampling approach is to shine a flashlight at the trees just to the side of where the bait is located, such that there is enough light to see the moths but the flashlight beam is not shining on them directly. If the flashlight beam hits the moths directly moths have a greatly increased tendency to fly off of the bait and at the flashlight beam. The collecting techniques for felt and baited trees are somewhat different, and are discussed below in the sections on each method.
Relative Effectiveness of Different Baits on Bait Trails/Felt Lines: Felt lines provide an easy opportunity to examine the relative effectiveness of different bait recipes, by baiting alternating felt strips with two different types of bait. Extraneous variables that would exist with a bait trail, such as tree diameter and texture, are eliminated with this approach. Kons has examined a wide variety of baits in this manner, including rotten bananas, rotten applesauce, rotten grape juice, rotten apple juice, rotten apple-banana juice, rotten banana juice, stale beer, grape wine, apple cider vinegar, molasses, brown sugar, and various combinations of these ingredients. It is essential that such comparisons be made on the same night in the same locality, as the effectiveness of any type of bait that attracts moths is extremely variable spatially and temporally, thus comparisons between sites or different nights generally provide no insight into the relative effectiveness of different baits. While strict quantitative sampling and statistical analyses were not used, qualitative observation was adequate to make some conclusions on the relative effectiveness of different baits. Of the above baits, the most effective combinations are mashed rotten bananas mixed with brown sugar and all natural rotten apple sauce mixed with brown sugar. How much brown sugar should be mixed in depends on how liquidy the bait is that it is being mixed with, thus going by precise measurements is pointless. We recommend mixing in enough brown sugar to get a wet paste-like bait, but not so much that the bait becomes dry and crusty. More brown sugar is optimal for painting trees on a bait trail than for felt strips, as the longevity of bait on a felt line tends to be longer. Some hands on field experience is necessary to learn how to make judgments on how much sugar to add. It is not clear that the brown sugar does anything to improve the effectiveness of these baits right after they are put up, but the brown sugar makes the bait thicker and it remains effective longer than if brown sugar is not used. On some occasions rotten fruit juices seem to perform as well or nearly as well as the banana or apple sauce baits right after they are put up, but after a few hours the effectiveness of fruit juice bait drops off considerably, especially under dry conditions. Also, the effectiveness of liquidy baits lasts notably longer on felt lines than on tree trunks. The banana or apple sauce brown sugar baits will remain at least somewhat effective during and after light to moderate rain, whereas fruit juice baits quickly loose effectiveness under rainy conditions. Apple cider vinegar, molasses, beer, and wine can attract moths when bait is working well, but they are much less attractive than banana or apple sauce baits, and on some nights when banana and apple sauce baits have attracted moderate or low numbers of moths these other baits have attracted few to none. Furthermore, Kons has seen no indication that adding either molasses, apple cider vinegar, beer, or wine, to apple sauce or banana bait does anything to increase the effectiveness of these baits; however adding liquid baits reduces the longevity of the bait's effectiveness by making the bait more fluidic. The relative effectiveness of rotten banana and rotten applesauce baits on felt is variable; on some nights one bait type has outperformed the other whereas on other nights both have performed comparably well. However, in Kons' experience banana-brown sugar bait tends to be much more effective on trees than apple sauce-brown sugar bait. Banana mush is thicker than apple sauce, and persists on trees much longer.
Felt Line: American Entomological Institute Property,
Catocala Desdemona, Pseudaletia unipuncta, and Hemieuxoa rudens feeding at felt strip baited with rotten apple sauce and brown sugar. Photo copyright Robert J. Borth 2006.
Baited Felt Lines: Baited felt lines involve tying nylon twine between two trees and attaching strips of felt with clothes pins or safety pines. Using safety pins requires more time initially, but this will prevent animals from pulling down the felt in areas where this could be a problem. The felt strips can then be dipped in bait, and checked later to collect Lepidoptera landed on the felt to feed off of the bait. To bait the felt pour bait into a plastic cup and walk to each felt strip and stick it about half way down into the bait. For banana-brown sugar bait initially it helps to have a stick to push the soft felt strips into the thick bait, but after a while the felt strips will become harder due to the encrustment of brown sugar, and the stick may no longer be necessary. It is best that the felt strips are orientated perpendicular rather than parallel to the direction of the twine. Otherwise, as one walks the length of the felt line Lepidoptera may be concealed on felt surfaces opposite to the collector. The felt strips can be orientated perpendicular by making two folds. First, the top corners should be folded together (each corner is folded 90 degrees) such that they form a line pointing down the midline of the felt strip. Then this folded top area should be folded over 180 degrees, and this folded over area should be attached to the twine. This results in the felt strip orientated perpendicular to the twine, as can be seen in the closest felt strip in the above picture.
The height at which felt strips are suspended can be important. They should not be so low to the ground that raccoons can reach up and grab them, or so close to other trees that raccoons can reach them by climbing trees. An optimal height is slightly lower than the chest of the collector. The optimal technique is to collect a specimen by holding a flashlight under one's arm and shining it just to the side of the felt strip, so a specimen can be seen but is not directly in the flashlight beam. One should then reach across with a collecting jar (it is harder to reach up while holding a flashlight under one's arm), holding the lid of the jar cracked at an angle just slightly above the opening and positioning the specimen between the opening of the jar and the lid. HLK has found it is most effective to capture moths on felt by contacting the moth with the lid of the jar and knocking it down through the opening of the jar. The jar should be held nearly upright as this is done, so other specimens in the jar will not slide around and loose scales. Great care must be exercised to avoid contacting the felt or the twine hard enough to shake the twine, as this can result in all specimens on felt strips connected to a segment of twine to flee. For diurnal collecting this usually cannot be avoided, as it is very difficult to collect most Rhopalocerans off of felt without netting them, and difficult to net them without bumping the felt line. In this respect baited trees or traps are often more advantageous for surveying for bait loving Rhopalocerans; however, many species of Rhopalocera have a greater tendency to return to a baited felt line after they are disturbed than is the case for many species of Nocturnal Lepidoptera.
[Add Picture of moths on a baited tree]
Baited Tree Trails: For baited tree trails, trees should be painted with a paste of mashed rotten bananas and brown sugar. The bait should be applied to trees with a paint brush slightly lower than the chest level of the collector.
Technique for collecting a moth off of a baited tree. Photo Copyright David B. Wahl 2006. The clear push pin represents a moth landed on the tree. The lip of the jar is touching the tree where one should tap the tree with the jar relative to the position of the moth. If the moth does not fly into the jar, the jar lip should be slid up the tree until it contacts the moth.
What was stated above under felt lines with respect to how to shine the flashlight and approach with a jar is equally applicable to baited trees. However, when collecting moths off of baited trees the best approach is often not to contact the specimen directly with the jar, but to tap the tree right below the moth with the lip of a jar. If the approach is good and the moth has not flown off of the tree before this tap occurs, for most moth species the specimen will fly into the jar nearly all of the time. In HLK's experience, for most species this technique captures the desired specimen off of a tree more often than trying to knock the moth into the jar by contacting it with the jar or the cover. However, in some cases the moth will remain on the tree after the tap, and in these cases the jar lip should be slid up the tree until it contacts the bottom of the desired specimen, which will usually then fly into the jar. If the moth flies up rather than down it will hit the cover of the jar and usually rebound into the jar (recall the cover of the jar should be angled just over the jar opening on approach). If the moth flies away perpendicular to the tree it will be between the jar and cover briefly, and a quick action is needed to close the lid over the moth before it turns and escapes. If the moth flies off of the tree sideways and perpendicular to a line between the collector and the tree it will escape unless it is netted. If a moth escapes the jar after the jar taps the tree it is very difficult to subsequently capture with a net. An attempt may be made by immediately steeping back and trying to spot the moth in a flashlight beam with the net ready to be swung. However, if a moth flies off of a tree as the collector is approaching the tree, and the collector is holding a net under their arm, with practice one can learn to react quick enough to net the moth as it flies off of a tree at least some of the time. Diurnal and wary nocturnal voucher species need to be netted. To net a specimen off of a baited tree approach with the rim of the net below the specimen, and use a net with a firm rim. If the specimen remains on the tree long enough to get the net right below the specimen, contact the specimen with the rim of the net touching the tree below the specimen, and swing up immediately as the specimen flies off. Scraping the net against the tree when the specimen is landed on the tree is more likely to result in a miss or a damaged specimen. When possible it is better to capture moths directly with a jar than with a net, because in a net it is easy for moths to rub scales off of the dorsum of their thorax (this problem does not occur with Rhopalocerans, which have the dorsum of their thorax largely devoid of scales).
Catocala muliercula feeding at a baited tree. Photo copyright Robert J. Borth 2006.
Advantages and disadvantages of baiting trees versus baiting felt: On a given night either a baited tree trail or a baited felt line may outperform the other even when the same bait is used for both, depending on some factors which we are aware of and some we do not yet understand. Some of the relative advantages of these two techniques are listed below.
Advantages of a baited felt line over a tree trunk bait trail
* Bait will persist longer on baited felt than on tree trunks. However, if good bait is used in accordance with our recommendations, with either technique it will remain effective for at least a full night barring rain or animal interference.
sites and habitat types lack a large number of easily accessible tree trunks,
especially in the western
* While it takes longer to put up felt lines initially, once the nylon twine and felt is up the felt can often be baited more quickly than tree trunks can be baited. Thus felt lines can be an efficient survey method when one is conducting surveys at one site over multiple consecutive days.
* Sometimes a baited felt line attracts more Lepidoptera than a baited tree trail, even when the same bait is used on both.
* Cryptic Lepidoptera are easier to see at night on felt strips than tree trunks.
* Apple sauce-brown sugar bait is effective on a felt line and can be used in combination with banana mush-brown sugar bait on alternating felt strips. However, apple sauce-brown sugar bait is generally not thick enough to persist well on a baited tree trail.
* Baited felt lines are generally less susceptible to interference by raccoons, unless they are hanging too low to the ground or within reach of other trees. However, if baited felt strips are damaged by mammals more time is needed to correct the problem. If a baited felt line is used in the same location over many weeks, local raccoons may figure out how to walk along the nylon twine upside down and access felt strips.
*Baited felt lines are less susceptible to being mobbed by swarms of ants. When baited felt is used in an area for multiple nights, ants may eventually find the twine and access the felt closest to the ends, but this problem can be eliminated by smearing gasoline on both ends of the nylon twine.
Advantages of tree trunk bait trail over a baited felt line:
* Initially it is much less time consuming to bait tree trunks than to put up nylon twine, attach felt strips, and then bait them. Thus, felt lines are often not suitable for surveys lasting a single night or under other conditions when set-up time is limited.
* Effectiveness of baited felt is adversely affected by wind. When there is enough wind to blow the felt strips around few moths tend to land on them. Baited tree trails can remain very effective under some conditions windy enough to render a baited felt line ineffective.
* If one bumps any part of a felt line it can scare off all of the Lepidoptera on all of the felt strips attached to a segment of nylon twine. This makes it difficult to net individuals of wary species off of a felt line without scaring away all of the other Lepidoptera present.
* No clean up work is required for a baited tree trail (banana mush does not persist in the environment for very long, whereas nylon twine and felt need to be removed when a survey is over).
* A baited tree trail is inconspicuous in contrast to a baited felt line, which can be hit by vandals.
THE TAPPING TECHNIQUE
The tapping technique is primarily for surveying for species in the genus Catocala (Noctuidae), although occasional records for other taxa are obtained from this method as well. Catocala is a species-rich genus, and many of the species do not readily come to MV or UV lights in many localities. Many of the species which infrequently show up at lights may come readily to bait when bait is attracting many moths, but this is often not the case at times and localities where these species are present. At some localities, this survey problem can be addressed with the tapping technique.
Tapping involves walking through forested areas and tapping tree trunks with a stick or net handle. If Catocala are resting on tree trunks in the vicinity of where the tree is tapped, they may fly off of the tree and become easily visible. The challenge is then to watch the flight of flushed individuals, and see where they land. Then one must carefully approach the Catocala’s new resting position, and determine if the individual is a desired specimen. If this is the case, one should attempt to capture the specimen with a net or jar. Capturing specimens with a jar is ideal for minimizing scale loss, but many individuals are simply too wary and can only be captured with a net. Individuals of certain species tend to be especially wary, such as Catocala lacrymosa. The technique for netting Catocala off of tree trunks is the same technique discussed under netting moths on bait trails in that section.
It is often easier to capture desired specimens on tree trunks if they are spotted on the trees without first being flushed. However, Catocala are often well camouflaged on their substrate, and tapping trees is often a much more efficient means of locating individuals.
As is the case with baiting, the effectiveness of tapping is extremely variable spatially and temporally. However, we have ideas as to what some but not all of the variables may be. Tapping is usually the most effective under hot and sunny conditions, with progressively fewer Catocala seen under cooler or cloudier conditions. This may be due to more Catocala individuals resting higher in the trees where they are not detected by tapping under these conditions. We have not tested this hypothesis, but we have observed Catocala flying and landing high up on tree trunks, just below the canopy. Tapping often works best from about to , but it may be effective earlier or later on hot days. Also, sites where tapping is more than minimally effective for most species are usually hydric hardwood forests or mesic-hydric hardwood forests along the margins of rivers, streams, ravines, lakes, or ponds. This observation may be due to these areas providing a less harsh microclimate under hot and sunny conditions. However, there are many situations where Catocala have been found in large numbers at lights and/or bait, but where tapping has uncovered few or no individuals, even under hot and sunny conditions in hardwood forests along water bodies. We cannot yet explain this observation. Catocala lineella and Catocala amica can be found commonly by tapping in mesic hardwood forests and xeric oak-pine forests not in proximity to any body of water, but when tapping in these types of areas we have found only occasional if any individuals of other Catocala species.
In our experience, some species of Catocala have rarely or never been found tapping, even at localities where these species are common at lights and/or bait and where tapping is uncovering many Catocala overall. Some species may rarely land on tree trunks within reach of a person. It is also possible some species may both be very well camouflaged on tree trunks and not prone to flying off when the tree trunks are tapped. Catocala similis may be found during the day but it rarely lands on tree trunks, and usually lands on the ground or under logs or brush. Catocala abbreviatella and Catocala whitneyi also may be found during the day, but these species land on the ground rather than on tree trunks. NAJLB volume I notes what specific species of FL Catocala we have found and not found with the tapping technique, and upcoming NAJLB volumes will include this type of information for other geographic areas and for individual survey dates.
Catocala amatrix resting on a tree trunk: This is an example where a Catocala can be easily spotted on a tree without tapping first. Photo copyright Robert J. Borth 2006.
Catocala residua (two individuals) cryptically resting on a tree trunk. Photo copyright Robert J. Borth 2006.
Malaise Trap at the American Entomological Institute property in
Malaise traps provide a flight barrier which some flying insects will collide with. Some individuals that collide with the side of the trap then fly upwards into the top section of the trap, which funnels them into a collecting container with ethanol. Our experience with malaise traps is limited to Kons’ collecting at the American Entomological Institute. While malaise traps trap a large array of Hymenoptera, Coleoptera, Diptera, and Hemiptera which are seldom or never encountered by the aforementioned survey methods, most species of Lepidoptera which have been found in the malaise trap are more common at lights and/or bait. Also, far fewer Lepidoptera species have been found in malaise traps than with these other methods. However, two Lepidoptera species, for which there are few other A.E.I. records, were taken in some numbers with the malaise trap: Neoprocis floridana (Zygaenidae) and Paratraea plebeja (Sphingidae).
Two Types of Collecting Jars. Left: jar charged with ethyl acetate-soaked paper towels stuffed in a pill bottle, with Viva paper towel substrate. Right: plaster bottomed collecting jar. Photo Copyright David B. Wahl 2006.
We use two different types of collecting jars in our Lepidoptera surveys. The left jar type is a mayonnaise jar. The bottom contains a narrow prescription pill bottle with the cover removed. A piece of paper towel is tightly stuffed into this pill container, and soaked with ethyl acetate. The ethyl acetate soaked paper towel in the pill bottle should be deep inside of the bottle and tightly stuffed such that there is no possibility any of this paper towel will stick out past the opening of the pill bottle and make contact with other paper towels in the jar. Otherwise, ethyl acetate will wick throughout all of the paper towels and come into contact with any specimens in the jar. Three layers of paper towels are placed into the jar over the pill bottle, one at a time. Each paper towel is folded over twice, such that the end result is four times the original thickness and ¼ the original surface area. The paper towels should be stuffed in the jar such that there are no gaps between the side of the jar and a layer of paper towel, to prevent moths from getting below the top layer. Any thick paper towels will do for the bottom two layers, but the top layer should be a very soft and thick variety. The Viva brand is the thick, soft paper towel variety that we have found to be most suitable, among the varieties we have tested. The top layer of paper towel should not be positioned such that it has a low point with sloping sides; otherwise, if multiple specimens are collected in the jar they will tend to congregated together in the low point, increasing the chance of scale loss. Once the jar is prepared, it will remained charged (saturated with ethyl acetate) for several weeks until it is used, but once it has been opened numerous times the paper towels in the pill bottle will need to be recharged with ethyl acetate.
We use the pill bottle type of jar for collecting small to medium sized moths at a sheet or bait trap, and for collecting at a bait trail. An advantage of this type of jar over a plaster jar is that the paper towel substrate is less abrasive than plaster, and moths are less prone to sliding in the jar and loosing scales. These jars tend to hold a charge longer than plaster bottomed jars but the concentration of ethyl acetate within the jar takes longer to reach saturation after the jars is opened. This is a disadvantage for collecting large moths such as Saturniidae and Sphingidae which require a higher concentration of ethyl acetate to subdue them quickly, and for these taxa we usually use plaster bottomed jars discussed below. A disadvantage of the pill bottle type of jar is that it is more time consuming to charge than a plaster bottomed jar, as one must remove and replace the three layers of paper towels. Also, if the paper towels become limp, or if one is not careful and leaves gaps between the edge of the paper towels and the sides of the jar, some specimens may find these gaps and crawl into them. Moths crawling into such gaps may slide their wings across paper towels or the side of the jar and loose scales. After two full collecting nights we recharge these jars and replace the top layer of paper towels, as the top layer has typically lost firmness by this point. Specimens can be removed from these jars by holding the jar upside down with the cover off and tapping the bottom of the jar, or tapping the lip against one’s hand. The paper towels may shift when this occurs, and need to be moved back into place.
Plaster bottomed jars are easier to charge. One merely needs to pour ethyl acetate over the plaster. When the plaster is saturated, the excess ethyl acetate can be poured into another such jar or back into its holding container. The plaster should then be dabbed with a paper towel so it is not wet on top. An advantage of plaster bottomed jars is initially they become saturated with ethyl acetate more quickly after they are charged or opened and reshut. This is why these jars may be more suitable for collecting large Saturniidae and Sphingidae. These large moths are also easier to capture with jars with a wider mouth than the mayonnaise jars, as is the case with many of the commercially available plaster bottomed jars.
Plaster bottomed jars have several disadvantages relative to pill bottle jars. Commercially available plaster bottomed jars typically have metal covers, and do not hold a charge nearly as long as the plastic covered mayonnaise jars. In addition, plaster appears to not hold a charge as long as paper towels. Plaster jars need to be charged at the beginning of each collecting night, and may need to be recharged during a night. In addition to the more frequent charging, these jars require more ethyl acetate to charge than the pill bottle jars. One can put plaster into the bottom of tighter plastic covered jars to reduce the need for frequent recharging, but having plaster in tighter fitting jars increases the likelihood specimens will become permeated with ethyl acetate.
Another disadvantage is that plaster is more abrasive than soft paper towels, and if these jars are tilted specimens inside may slide on the plaster and loose scales. If one puts paper towels over the plaster, ethyl acetate may wick into the paper towels and permeate specimens. Even without paper towels over the plaster, we have found that moths left in plaster bottomed jars more than a few hours often become permeated with ethyl acetate. This is rarely a problem with pill bottle jars, unless ethyl acetate soaked paper towel ends up sticking outside of the opening of the pill bottle.
If specimens become permeated with ethyl acetate, they should be removed from a jar and air dried as soon as possible. Larger and medium sized specimens typically incur at most minor damage, such as the wing margins curling over slightly. However, taxa with large fat reserves in their abdomens seem to be more likely to have the wings become greased if the specimens were in contact with ethyl acetate. However, small moths that are permeated with ethyl acetate may incur more serious damage, such as the folding and crinkling of wings. Collecting small moths with pill bottle jars greatly reduces the chance of this problem occurring.
With both types of jars, it is important to have the cover open as little as possible while collecting. The more the cover is opened, the more the jar will become discharged and the longer it will take to regain a charge. If moths in jars are not quickly subdued by ethyl acetate fumes, there is an increased chance they will damage their wings, with this chance increasing with larger sized moths.
It is also important to keep jars used to collect multiple specimens upright as much as possible. When jars are tilted, specimens in the jar may slide and loose scales, especially with plaster bottomed jars.
In addition, one should not pack too many moths into the same jar, or the chance of scale loss increases. How many moths can be safely placed into a single jar depends on the size of the moths collected with that jar. For large moths such as large Sphingidae and Saturniidae, it is generally best to have only one specimen in a jar at a time. For small moths, a dozen or more may be collected in a pill bottle jar without the specimens damaging each other. Large moths should not be collected with the same jars that already contain small moths, as large moths will often damage small specimens before they are subdued. Lepidoptera should not be collected in the same jars as other insects, since many other types of insects take longer to subdue and will crawl over Lepidoptera specimens denuding them of scales.
When conducting biodiversity blitzes, we like to keep 18 or more freshly charged jars on hand. On a good night, during the course of a biodiversity blitz one will need to collect many specimens to document all of the species encountered. Having a large number of jars enables us to rotate jars such that we do not have to place too many specimens into one jar and such that jars have plenty of time to recharge between uses.
Collecting jars should not be exposed to sunlight for any prolonged period of time, as this will cause condensation on inner surfaces of the jar. If Lepidoptera specimens contact this condensation their wings may become stuck to the sides of the jar, and many scales may be lost when they are removed. Also, paper towels in charged jars exposed to sunlight will become limp, and need to be replaced.
Specimens should not be left in collecting jars for too long. We have noted than in plaster bottomed jars specimens may become permeated with ethyl acetate after a few hours. Specimens will stay in good condition in pill bottle jars much longer, but if they remain in these jars longer than eight hours they may become prone to wing crinkling or greasing. If specimens cannot be field pinned, they should be transferred from collecting jars into a holding container. Holding containers are discussed under field pinning below.
Specimens should also not be removed from collecting jars too quickly, or they may revive. Larger moths need to be retained in charged jars longer than smaller ones. We recommend leaving moths in charged collecting jars at least one hour before they are removed. If specimens revive in a holding container this could be disastrous, as one large specimen that has revived could damage many others. If a field pinned specimen revives, it could flap its wings and damage any adjacent specimens. If one is collecting and using a holding container, it is a good idea to maintain a low concentration of ethyl acetate in the holding container throughout the night. This can be accomplished with a soda bottle cover containing stuffed paper towel soaked with ethyl acetate. If a field pinned specimen were to revive, the field pinning box should be placed in a two gallon zip loc bag after a piece of ethyl acetate soaked paper towel is pinned into a corner. The bag should be removed after about an hour.
If one is collecting in proximity to a freezer, it is possible to avoid the use of ethyl acetate altogether. One can use the pill bottle type jar without the pill bottle, and place specimens in a freezer shortly after they are collected. The bottom of the collecting jar should have a substrate like paper towels, because if moths contact a glass bottom in the freezer they can become stuck to the bottom via condensation when the jar is taken out of the freezer. Freezing live specimens without first subduing them with a chemical agent does have its disadvantages. Larger specimens may damage their wings in an uncharged jar as soon as they are placed into the jar, and incur damage before they are subdued by freezing. Also, many specimens that are frozen live will have their wings fold down perpendicular to their thorax after they are removed from the freezer. This makes pinning and spreading these specimens more difficult, especially if they are dried and later humidified before they are pinned or spread.
Some collectors use cyanide compounds with collecting jars. While these and some other compounds may subdue specimens quicker than ethyl acetate, we do not use them because they are so much more dangerous. Also, we have been told by various people that cyanide compounds tend to dry specimens out, making them more difficult to field pin or spread. While ethyl acetate is much safer than cyanide compounds, it is still flammable and unhealthy to breathe. One should never use ethyl acetate around flame, and collecting jars should only be charged and opened outdoors.
Field Pinning Box:
Field Pinning: We field pin moth specimens shortly after collecting them in the field. Once specimens are field pinned, there is no longer a danger of specimens sliding around and loosing scales in holding containers. Large specimens should be braced pinned, as sometimes the largest specimens will otherwise rotate and contact other specimens when driven on bumpy roads. One brace pine should be placed along the anterior margin of each forewing in the basal one half of the wing margin, where the coastal vein is strong. This is illustrated in the above picture for the large Saturniids Eacles imperialis and Citheronia sepulchralis. Brace pinning near the wing apices could result in the specimen shifting and the pin tearing through or folding over the wing. In contrast to boxes for the permanent preservation of dried specimens, field pinning boxes where fresh specimens will be stored at ambient temperatures for several days or longer should not be air tight. If specimens are placed in tight containers before they are dried out and stored at ambient temperatures, they will rot after a couple of days, or perhaps sooner under hot conditions. However, if one wishes to keep specimens relaxed for spreading without having to humidify them later, a tight field pinning box will be needed, or alternatively, any schmidt box sized field box that can be sealed in a 2 gallon Zip Loc bag. Freshly pinned specimens stored in this manner will need to be kept in a cooler or portable refrigeration unit if a collecting trip lasts more than a couple of days. However, freshly pinned specimens do keep well in tight wooden schmidt boxes, where they will dry out without rotting. This is not the case with tight fitting plastic or metal boxes. When field pinned specimens have completely dried out after a collecting trip, they should quickly be frozen or fumigated to prevent damage from collection pests. After specimens have been dried out, cardboard or loose fitting schmidt boxes can be sealed in 2 gallon Zip Loc bags with fumigant. In the field, loose fitting field pinning boxes should never be kept on the ground, and should only be outside of a vehicle when a collector is there working with them and keeping an eye on them. Otherwise, specimens will be vulnerable to damage by ants or other pests.
A header label should always be placed with sets of specimens with the same data as soon as they are field pinned. At a minimum the header label should include the date, survey method, and at least a code for the survey locality. If the specimens will be left with a header label for a long period of time before they can be given individual labels, it is best to include a full data label as the header label, including the additional information of GPS coordinates, collector(s), and habitat.
If specimens are not field pinned, they can be stored in coffee cans or rubber maid containers layered with soft paper towels (such as the Viva brand) or cotton. These containers can then be stored in a freezer after a collecting trip. However, if these holding containers are not refrigerated in the field, the specimens will begin to rot after a few days, or perhaps sooner if conditions are hot or holding containers are exposed to prolonged periods of sunlight. Holding containers should not be tilted or specimens may slide and loose scales. It is best to have specimens field pinned before traveling on bumpy roads.
For Rhopalocera, freshly collected specimens can either be field pinned or placed into envelopes. Either glassine or paper envelopes work for this purpose. Specimens should be placed in the envelopes with the wings folded up, and the ventral wing surfaces in contact with the sides of the envelope. The dorsal wing surfaces are more prone to scale loss, and if the wings are folded down in an envelope they will usually crease such that the specimen can never be properly spread. We recommend against placing moths in envelopes, because most moths cannot be identified if only the ventral wing surfaces are visible, thus dried moths stored in envelopes will need to be spread before they can be identified. Many Rhopalocera can be identified in envelopes from the ventral wing surfaces, although identification is generally easier if both the dorsal and ventral wing surfaces can be examined.
Humidification of Dried Specimens
If one wishes to spread specimens that have dried out after field pinning, the specimens will need to be humidified. Rubbermaid makes a variety of tight plastic containers that can be used for this purpose. Paper towels on the bottom of these containers can be saturated with spray-on Lysol, and a piece of styrofoam can then be placed over the paper towels onto which specimens may be pinned. The reason to use Lysol instead of water is to prevent mold growth on specimens. How long it takes specimens to relax will depend on their size, but specimens should not be left in a humidifier at room temperature for more than 12 hours after they have relaxed. Humidifiers containing relaxed specimens may be placed in a freezer, and removed when one is ready to spread the specimens.
It is always easier to spread specimens fresh than after they were dried out and later relaxed. The major disadvantage to relaxing specimens is that some specimens are more prone to having the wings droop after they are spread if they have been relaxed, even if the specimens have dried out completely before being removed from the spreading board. This problem frequently occurs with thin bodied specimens, such as many microlepidoptera, many Geometridae, deltoid Noctuids, Lithosiini, and other species which have thin bodies. The problem occurs much less often with robust bodied specimens and Rhopalocera (including thin bodied species). Also, some green specimens loose their green coloration when they are relaxed. For eastern North American species, this can occur with green species of Nemorinae, Theclinae, and Noctuidae: Feralia, Cryphia, and Agriopodes.
It is not necessary to spread most Lepidoptera specimens for the
purposes of vouchering specimens for biodiversity inventory data. Having Lepidoptera specimens spread
is useful for studying hindwing characters and
for specimen photography. For taxonomic studies, it is useful to have
representative series of spread specimens for each species in an area to study hindwing characters. However, for identification
purposes, most Nocturnal Lepidoptera species in
Also, note that the humidification process degrades specimen’s DNA. Specimens that are to be used for molecular studies should have legs removed for sequencing prior to any humidifying.
LEPIDOPTERA FIELD SURVEY EQUIPMENT SUPPLIERS
NOTE: The below links for Lepidoptera survey equipment suppliers are provided by the NALBLLC for informational purposes, as all of these suppliers offer equipment we have found useful to our scientific research. None of these links were provided at the request of or under any financial incentive by the suppliers.
We recommend the stainless steel insect pins offered by Petr
Kabatek and Martin Hulovec
Rose Entomology: We recommend this supplier for high quality nets. This supplier formally offered excellent 175 and 400 watt AC MV light units, but unfortunately to our knowledge this is no longer the case.
Koehn Traps: The below web site provides information on the Koehn bait traps mentioned on this web page in addition to other Lepidoptera survey equipment.
BioQuip Products: In addition to several items noted above, this company offers a wide array of entomological equipment and books.
33 Watt AC BL UV Lights: [Fill in Info.]
Walmart: Walmart is a good place to purchase king sized white sheets, nylon twine, AC photoelectric switches, AC BLB blacklights, deep cycle outboard batteries, battery clips (clips used to attach a DC UV light to a battery), 175 watt Mercury Vapor light bulbs, felt, Viva paper towels, and Rubbermaid containers that can be used to construct trap and wick components.
ACKNOWLEDGEMENTS: We are very appreciative of those individuals who assisted with the construction of traps or other collecting equipment, including: Hugo and Sharon Kons, Sr., Danny McFather, and Jim Lloyd. In addition, HLK thanks Richard Merkhofer for providing an inverted cone platform bait trap when HLK was first getting involved with serious scientific collecting. In addition, we are especially grateful to David B. Wahl for taking many of the pictures used on this web page with his digital camera. We thank David Wahl and the American Entomological Institute for infrastructural support. Additional acknowledgments for those who assisted with our Florida Lepidoptera survey project (the Borth photos on this web page were taken during this project) appear in NAJLB volume I.