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j ournal of The Lepidopterists' Society

Volume 33                                    1979                                     Number 3

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Journal of the Lepidopterists' Society 33(3), 1979, 153-161

THE MALAISE TRAP AS A MEANS OF SAMPLING BUTTERFLY POPULATIONS IN KENTUCKY1

Charles V. Covell, Jr.

Dept. of Biology, University of Louisville, Louisville, Kentucky 40208

AND

Paul H. Freytag

Dept. of Entomology, University of Kentucky, Lexington, Kentucky 40506

ABSTRACT. Butterflies representing 57 species in 9 families were collected by means of Malaise traps at 10 localities in Kentucky during the summers of 1970-1977. The species are listed along with collecting sites, months of capture, and numbers of individuals caught. Discussion of the potential of Malaise traps for sampling butterfly populations includes an analysis of two of the three broods of Phyciodes tharos (Drury) at Lexington, Kentucky as sampled by Malaise traps in 1971.

One of the problems in carrying out qualitative and quantitative studies of butterfly populations in a given area is capturing specimens. Butterflies, often highly mobile and difficult to approach, have traditionally been stalked with net and killing jar—a very time-consuming procedure. Some species—those that can be attracted to rotten fruit and other non-nectar adult foods—can be collected in bait traps but this technique can be used for only a small proportion of species in most butterfly communities. The use of pheromone traps for butterflies is at best in its infancy, and would present similar limitations in breadth of appeal as the bait trap. One promising technique is the Malaise trap (Fig. 1), which collects insects by blocking their passage and taking advantage of their instinct to climb upward. This trap has already been modified by various workers for different purposes but

1 Contribution No. 192 (New Series) of the Department of Biology, University of Louisville. This paper (78-7-170) is published with the approval of the Director of the Kentucky Agricultural Experiment Station, Lexington, Kentucky 40506.

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apparently this paper is among the first to report its use in sampling butterfly populations.

Townes (1962, 1972) adapted the Malaise trap for the purpose of collecting large numbers of Hymenoptera for taxonomic purposes. Others have followed, either to assess total insect communities (Geijskes, 1968; Matthews & Matthews, 1970), or to collect particular insect groups (Breeland & Pickard, 1965, for mosquitoes; Adkins et al., 1972, for Tabanidae). Lepidoptera are usually represented as a percentage of the whole catch in general insect surveys. Percentages of each order are based on a count of all members of that order in the sample container. Thus moths and butterflies are generally lumped together, and rarely are they separated even to family level. Geijskes (1968) found in Surinam that Lepidoptera were 14.3% of catches in 1963-64, but seasonal fluctuations of 8-37% were noted. Matthews & Matthews (1970) found that Lepidoptera constituted 7.2% of their total catch during 13 weeks in 1967 at Rensselaerville, New York. Their Lepidoptera were "almost exclusively moths, the bodies of over half (49%-69%) measuring less than 3.0 mm excluding antennae."

One comprehensive study of butterfly populations collected by Malaise trap was that of Owen (1971), who used this technique in Kampala, Uganda, in 1965, and at Freetown, Sierra Leone, in 1968. He showed monthly fluctuations in numbers of individuals collected, grouping his catch by family. His only tabulation at the species level was Acraea bonasia (Fabr.). That common butterfly was present all year, but showed a definite peak in February and March (Owen, 1971: 70). While Malaise trap samples played only a small part in his overall study, Owen was possibly the first to demonstrate the value of Malaise traps in sampling butterflies. More recently Walker (1978) has demonstrated its value as a technique for studying butterfly migration.

Methods

In 1970 the junior author, a leafhopper specialist, began a program of Malaise trap sampling at several localities in Kentucky: Lexington (Fayette Co.); Glendale (Hardin Co.); Bardstown (Nelson Co.); Robinson Forest (Breathitt Co.); Princeton (Caldwell Co.); Paris (Bourbon Co.); Spears (Jessamine Co.); and rural areas in Pulaski and Wayne counties. The junior author separated the Lepidoptera from other orders and the senior author subsequently identified them for the Kentucky Lepidoptera Survey. Although the Lepidoptera collected were mainly moths, a large number of small and medium-sized butterflies appeared in the samples. This material was augmented by specimens collected by University of Louisville graduate students under the supervision of the senior author in Bernheim Forest (Bullitt Co.).

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FlG. 1. Malaise trap at Bernheim Forest, Bullitt County, Kentucky, 1977. The trap was 6 ft long, 4 ft wide, and 6 ft 8 in high at one end. At the high point, a hole of 2Va in diameter led into a plastic jar, to which a plastic cyanide jar could be screwed by means of lids glued back to back and drilled with a similarly large opening to let the insects through.

Two variations of the Malaise trap were employed to obtain the results reported here. The traps used by the junior author at all sites except Bernheim Forest were Model 300.5 from Survival Security Corporation, Lake City, Minnesota 55041 (not illustrated). About 7 ft high, these traps consisted of dark nylon netting in four panels rising to a central peak supported by an aluminum pole. The top of the trap had an inverted plastic cone to direct the insects into a smaller cone placed snugly beneath the first, then narrowing downward into a cyanide killing jar. These components were supported by the center pole. Entrance space between the two cones was provided by cuts about lA inch deep around the top of the inner cone. The traps were selective for small insects, especially leafhoppers, so few large butterflies were included in the samples.

The trap used at Bernheim Forest (Fig. 1) was built by University of Louisville graduate student Larry Canterbury according to the directions of Townes (1972). The openings into the killing jar were larger in this trap, and several of the large butterfly species listed in Table 2 were taken only at the Bernheim Forest site. The Bernheim trap was encircled by barbed wire to discourage tampering.

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Table 1. Numbers of total butterfly species of each family collected by Malaise trap in Kentucky, 1970-1977. Percentages of the total are indicated in the right-hand column.

Family

Hesperiidae

Papilionidae

Pieridae

Riodinidae

Lycaenidae

Libytheidae

Nymphalidae

Danaidae

Satyridae

Total butterfly species                               131                         57                        43.5

Results

The butterflies collected in Malaise traps were identified by the senior author and named according to the current checklist for North American butterflies (Dos Passos, 1964) and later modifications such as Howe (1975). Covell (1974) listed 123 butterfly species from Kentucky, and since then 8 more have been added. As of this writing, 57 of the 131 species, or 43.5%, have been collected in Malaise traps. No additions to the state list have resulted yet from these samples, but substantial numbers of new county records and some additional seasonal information has been recorded.

Table 1 indicates the Malaise-trapped butterfly species in each family compared with the total number known from Kentucky in that family. Species that have not been collected include (1) 5 species that are clearly "strays" and known from single Kentucky records; (2) 23 species that are either very rare, or which are found in very restricted, specialized habitats not yet sampled by Malaise trap; or (3) some of the very large butterflies which were not caught despite the Bern-heim trap with large opening. It may also be that flight and walking habits of some species, not yet appreciated, may account for their absence from samples. Only one family occurring in Kentucky, the Riodinidae, has not been taken by Malaise trap; and these fly for short periods in very specialized habitats.

Table 2 lists all the butterfly species collected by Malaise trap in Kentucky from 1970 through 1977. Although the number of specimens collected by this technique over the eight-year period is only 1,883, one must remember that except at Bernheim Forest the traps were not designed or placed for butterfly collecting. The majority of spec-

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Table 2. List of species of butterflies in each family collected by Malaise trap in Kentucky, 1970-1977. To the right of each species name are numbers representing localities from which each was collected (1-10), the months of capture (1-12), and the total number of specimens taken. Localities by number are as follows: 1, Bernheim Forest, Bullitt Co.; 2, Lexington, Fayette Co.; 3, Glendale, Hardin Co.; 4, Spears, Jessamine Co.; 5, rural Mercer Co.; 6, Robinson Forest, Breathitt Co.; 7, Princeton, Caldwell Co.; 8, Bardstown, Nelson Co.; 9, rural Wayne Co.; and 10, Paris, Bourbon Co.

Species

Localities

Specimens

Hesperiidae

Amblyscirtes hegon (Scudder) Euphyes vestris metacomet (Harris) Poanes zabulon (Bdv. & LeConte) Poanes hobomok (Harris) Atrytone delaware (Edwards) Atalopedes campestris (Bdv.) Pompeius verna (Edw.) Wallengrenia egeremet (Scudder) Polites coras (Cramer) Polites themistocles (Latreille) Polites origenes (Fabr.) Thymelicus lineola (Ochs.) Ancyloxypha numitor (Fabr.) Nastra Iherminier (Latreille) Pholisora catullus (Fabr.) Pyrgus communis (Grote) Erynnis icelus (Scudder & Burg.) Erynnis brizo (Bdv. & LeConte) Erynnis horatius (Scudder & Burg.) Erynnis juvenalis (Fabr.) Epargyreus clarus (Cramer)

Papilionidae Battus philenor (Linn.) Papilio troilus Linn. Graphium marcellus (Cramer)

Pieridae Pieris rapae (Linn.) Colias eurytheme Bdv. Colias philodice Godart Eurema lisa Bdv. & LeConte Eurema nicippe (Cramer) Anthocharis midea Hubn.

Lycaenidae Harkenclenus titus mopsus (Hubn.) Satyrium calanus falacer (Godart) Calycopis cecrops (Fabr.) Callophrys henrici (Grote & Rob.) Strymon melinus Hiibn. Lycaena hyllas (Cramer) Lycaena phlaeas americana Harris Everes comyntas (Godart)

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Table 2. Continued.

Species

Localities

Months

Specimens

Celastrina argiolus pseud-argiolus (Bdv. & LeConte)

LlBYTHEIDAE

Libythaena bachmanii (Kirtland)

Nymphalidae Asterocampa celtis (Bdv. & LeConte) Asterocampa clyton (Bdv. & LeConte) Limenitis arthemis astyanax (Fabr.) Vanessa atalanta (Linn.) Vanessa virginiensis (Drury) Precis coenia (Hiibn.) Polygonia interrogationis (Fabr.) Polygonia comma (Harris) Chlosyne nycteis (Doubleday) Phyciodes tharos (Drury) Boloria bellona (Fabr.) Speyeria cybele (Fabr.) Euptoieta claudia (Cramer)

Danaidae Danaus plexippus (Linn.)

Satyridae

Cyllopsis gemma (Hiibn.) Euptychia hermes sosybius (Fabr.) Megisto cymela (Cramer)

2,3,7,8

6-8

58 8 1 5 1 4 6 1

10 379

69 7 7

Total: 1,883

imens were small species, the common Phyciodes tharos (Drury) constituting 20% of the total. Its wingspan is approximately 3 cm. Also, the traps were placed in open fields and meadows with two exceptions: the Robinson Forest and Bernheim Forest sites. The few Satyridae collected can be attributed largely to that factor, since most of the Kentucky members of this family are woodland species. Furthermore, although some early spring collecting was done, the period from mid-March to the end of April was largely neglected; and several early spring butterflies were not collected—especially those restricted to woodland habitats. While only months of capture are indicated here, further study of the data would reveal trends in abundance of given species at a particular locality during a given year. These data might be valuable in understanding population dynamics, especially when correlated with climatic factors such as temperature and rainfall. An example of a more precise analysis is given in Fig. 2 for Phyciodes tharos, which has three broods in Kentucky. At Lexington in 1971, 88

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"1 1 I-----m-----1

**R- MY                                  J^                              JULY                                AUG.                                 SEP                                  OPT

23-30 1 -11 12-21 21-30 1 -9 9-21 21-30 1 -11 11-20 20-31 1 -9 9-20 20-30 1 -i3 l>21 21-30 1 -U

FlG. 2. Temporal distribution of Phyciodes tharos (Drury) collected in a Malaise trap in a Lexington, Kentucky, meadow, 23 May-11 Oct. 1971.

individuals were collected during the 17 time increments indicated on the graph. From prior experience we expect the three broods to occur in spring, midsummer, and late summer to fall. We are not certain if the single capture of 12-21 May represents the spring or midsummer brood. The spring brood was not properly sampled since that trap was not set up until about 20 April. The midsummer peak at that site in 1971 was apparently during 1-11 July, with 24 individuals collected. The next peak during the last 10 days of August and the first 13 of September was also substantial. If the trap had been checked daily instead of at rather irregular intervals, a more sensitive picture of the dynamics of P. tharos could have been obtained. Similar data from several years would be interesting, to give comparisons of both abundance and peak flight times for adult P. tharos. The Malaise technique can be used to remove individuals permanently from the population by use of a killing jar; or individuals can be marked, released, and recaptured on succeeding days for studies of that nature.

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Since Fig. 2 was constructed in hindsight from butterflies collected by the junior author in 1971, one should not assume that it is intended to give anything more than a rough picture of P. tharos dynamics at the Lexington site that summer.

Conclusions

Large numbers of insects, including such fast fliers as moths and butterflies, can be collected with relatively little effort by using Malaise traps. By experimentation with the basic design of the trap one can enhance the efficiency of capture of either butterflies in general, or certain desired species. Some of the variables which still need attention include netting color, texture, and durability; trap size and shape; placement of collecting container, size and shape of opening into container; dimensions of container itself. Position of the trap in suitable habitat is also essential to maximize collection. Placement in a butterfly fly-way through a forest is an example of proper choice in this respect. Addition of bait may increase captures of certain desired species. If killed specimens in excellent condition are required, one must seek a long-lasting killing agent of strength sufficient to prevent damage by beetles and large insects (including Lepidoptera) that get into the container. A large live-catch cage could also be used, especially if one does not wish to make a general survey or kill everything that enters the trap. By using such a cage one can free insects that one is not interested in keeping, and thus avoid needless killing of large numbers of other insects. The more frequently the trap is emptied, the better one can expect specimen condition to be. In the collections studied in this survey, however, the condition of butterflies was remarkably good; a large proportion was nearly perfect and good enough to put in a collection. A major drawback to using killed specimens from Malaise traps seems to be the unpreventable problem of wings folding down beneath the body as the insect dies. Such specimens often have drooping wings, even after a good job of relaxing and spreading. Experimentation with other killing agents may alleviate this problem.

In addition, some other negative aspects of Malaise trap collecting in general include:

(1)  Expense: Unless one makes the trap himself, commercially available models run from $100 to more than $300.

(2)  Weather: Rain may ruin samples; wind can knock down the trap or bring tree limbs down on it; and sun, rain, and wind can cause deterioration of some netting materials, e.g., nylon. Dacron is more durable according to Townes (1972).

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(3)  Vandalism: Despite signs and even barbed wire fencing (Fig. 1), traps are often prey to vandals in isolated localities. We know of cases in which traps have been destroyed or stolen on seemingly protected property.

(4)  Lack of selectivity: As mentioned above, one is likely to kill large numbers of insects indiscriminately by this technique unless a live-catch container is used and the trap is emptied daily.

Despite these shortcomings, however, Malaise traps show great promise for a wide variety of insect population studies, and are increasingly used throughout the world. This survey has added much information to the current study on butterflies of Kentucky; the moth material, when identified, should provide numerous important records for that aspect of the survey.

Acknowledgments

The authors wish to thank their student assistants and colleagues for help in operating the Malaise traps in the various localities, and for sorting the samples: D. P. Beiter, A. J. Brownell, L. E. Canterbury, W. B. Early III, G. F. Florence, C. H. Kaster, J. S. Lesshafft, Jr., J. Pohlman, H. G. Raney, S. Reigler, and C. K. Sperka. We are also grateful to the Isaac Bernheim Foundation, Louisville, Kentucky, for the funding to carry out the survey of Bernheim Forest.

Literature Cited

Adkins, T. F. Jr., W. B. Ezell Jr., D. C. Sheppard & M. M. Ashley Jr. 1972. A

modified canopy trap for collecting Tabanidae (Diptera). J. Med. Entomol. 9(2):

183-185. BREELAND, S. G. & E. PlCKARD. 1965. The Malaise trap—an efficient and unbiased

mosquito collecting device. Mosquito News 25: 19-21. COVELL, C. V. Jr. 1974. A preliminary checklist of the butterflies of Kentucky. J.

Lepid. Soc. 28(3): 253-256. Dos PASSOS, C. F. 1964. A synonymic list of the Nearctic Rhopalocera. Mem. Lepid.

Soc. 1: 1-145. GEIJSKES, D. C. 1968. Insect collecting in Surinam with the help of "Malaise'' traps.

In Studies on the fauna of Surinam and other Guyanas, no. 39. Natuurwetensch.

Studiekring Surinam Ned. Antillen 48: 101-109. Howe, W. H. 1975. The butterflies of North America. Doubleday, Garden City, N.J.

633 p., 97 pi. Matthews, R. W. & J. R. Matthews. 1970. Malaise trap studies of flying insects in

a New York mesic forest. I. Ordinal composition and seasonal abundance. J. New

York Entomol. Soc. 78: 52-59. Owen, D. F. 1971. Tropical butterflies. Clarendon Press, Oxford. 214 pp. TOWNES, H. 1962. Design for a Malaise trap. Proc. Entomol. Soc. Washington 64: 253-

262.

--------- 1972. A light-weight Malaise trap. Entomol. News 83: 239-247.

Walker, T. J. 1978. Migration and re-migration of butterflies through northern peninsular Florida: Quantification with Malaise traps. J. Lepid. Soc. 32(3): 178-190.