-^vIthsoiv^v Volume 58 Number 1 MAY 1 2004 22 April 2004 ^RARlE; ISSN 0024-0966 Journal of the Lepidopterists' Society Published quarterly by The Lepidopterists' Society THE LEPIDOPTERISTS' SOCIETY Executive Council Susan J. Weller, President Martha R. Weiss, Vice President Lawrence F. Gall, Immediate Past President Ernest H. Williams, Secretary Rienk de Jong, Vice President Kelly M. Richers, Treasurer Angel Viloria, Vice President Members at large: David Ahrenholz William E. Conner Akito Kawaliara Philip |. DeVries Rebecca Simmons Jane M. Ruffin y. Boiling Sullivan Charles V Covell yr. Erik B. Runquist Editorial Board John W. Brown (Chairman) Michael E. Toliver (Journal) Lawrence F. Gall (Memoirs) Phillip Schappert J. (News) John A. Snyder (Website) Carla M. Penz (at large) Honorary Life Members of the Society Charles L. Remington (1966), E. G. Munroe (1973), Ian F. B. Common (1987), John G. Franclemont (1988), Lincoln P. Brower (1990), Douglas C. Ferguson (1990), Hon. Miriam Rothschild (1991), Claude Lemaire (1992), Frederick H. Rindge (1997) The object of The Lepidopterists' Society, which was formed in May 1947 and formally constituted in December 1950, is "to pro- mote the science of lepidopterology in all its branches, ... to issue a periodical and other publications on Lepidoptera, to facilitate the exchange of specimens and ideas by both the professional worker and the amateur in the field; to secure cooperation in all mea- sures" directed towards these aims. Membership in the Society is open to all persons interested in die study of Lepidoptera. All members receive the Journal and the News of The Lepidopterists' Society. Prospective members should send to the Assistant Treasurer full dues for the current year, to- gether with their full name, address, and special lepidopterological interests. In alternate years a list of members of the Society is is- sued, with addresses and special interests. Active members—annual dues $45.00 within the U.S., $50.00 outside the U.S. Affiliated members—annual dues $10.00 within the U.S., $15.00 outside the U.S. Student members—annual dues $20.00 within the U.S., $25.00 outside the U.S. Sustaining members—annual dues $60.00 within the U.S., $65.00 outside the U.S. Life members—single sum $1,800.00 Institutional subscriptions—annual $60.00 Airmail postage for the News $15.00 Send remittances, payable to The Lepidopterists' Society, to: Kelly M. Richers, Treasurer, 9417 Carvalho Court, Bakersfield, CA 93311; and address changes to: Julian P. Donahue, Natural History Museum, 900 Exposition Blvd., Los Angeles, CA 90007-4057. For information about the Society, contact: Ernest H. Williams, Department of Biology, Hamilton College, Clinton, NY 13323. To order back issues of the Memoirs, write for availability and prices to Kenneth R. Bliss, 28 DuPont Avenue, Piscataway, NJ 08854. The additional cost for members outside the U.S. is to cover mailing costs. c Journal of The Lepidopterists' Society (ISSN 0024-0966) is published quarterly by The Lepidopterists' Society, /o Los Angeles County Museum of Natural History, 900 Exposition Blvd., Los Angeles, CA 90007-4057. Periodicals postage paid at Los Angeles, CA and at additional mailing offices. POSTMASTER: Send address changes to The Lepidopterists' Society, % Natural History Museum, 900 Exposition Blvd., Los Angeles, CA 90007-4057. Cover illustration: Two late-instar Monarch (Danaus plexippus (L.): Nymphalidae) caterpillars "face off' over die last bit of Milkweed (Asclepias) leaf, Northern Wisconsin, USA. Photo by Michael Toliver. Journal of The Lepidopterists' Society Volume 58 2004 Number 1 Journal of the Lepidopterists' Society 58(1), 2004, 1-6 SEASONAL DYNAMICS OF LEAF-TYING CATERPILLARS ON WHITE OAK John T Lill 1 Department of Biology, University of Missouri-St. Louis, 8001 Natural Bridge Road, St. Louis, Missouri 63121, USA ABSTRACT. This study examined the seasonal pattern of leaf tie construction and occupancy by caterpillars associated with white oak, Quercus alba, in Missouri. Thirty white oak trees were monitored over die course of a season, recording the phenology of leaf tie construction, occupancy, and abandonment by 14 different species of leaf-tying caterpillars. Larvae of Pseudotelphusa sp. (Gelechiidae) created most of the initial leaf ties, many of which were secondarily occupied by a variety of other leaf tiers. In addition, non-tying caterpillar species from a variety of families were common secondary occupants. As many as 6 different species and 15 different individual larvae were found occupying a single leaf tie over the course of the season. In selecting pre-existing leaf ties for colonization sites, die leaf tiers did not discriminate between ties of different ages. On average, one-third of the leaves on a branch were incorporated into a leaf tie at some time during the season. Despite their abundance, leaf ties in this system appear to be a limiting resource. Additional key words: Leaf tie, insect phenology, positive interactions, Quercus alba, shelter-builders. Shelter-building caterpillars are a conspicuous com- An important first step in understanding the dy- ponent of the insect herbivore fauna attacking temper- namics of these interactions is to document die sea- ate broad-leaved trees (Frost 1959, Prentice 1965). A sonal pattern of shelter construction (i.e., resource variety of caterpillars in at least 12 (Berenbaum 1999) availability), maintenance, and occupancv (resource and as many as 27 (Jones 1999) different families use use) by different species of caterpillars. Here. I de- silk to construct leaf ties, webs, folds, and rolls that scribe the natural history of leaf tie construction and typically serve as both shelters and feeding sites (room occupancy of the leaf ties found on saplings of white and board) for developing larvae. These leaf shelters oak (Quercus alba L.). are often colonized subsequently by other arthropods, Materials and Methods including other shelter-building caterpillars (Carroll & Kearby 1978, Cappuccino 1993, Cappuccino & Martin This study was conducted in east-central Missouri 1994, Lill 1999, Martinsen et al. 2000, Lill & Marquis at Cuivre River State Park. The park consists of second 2003), many of whom oviposit in existing shelters (Lill growth oak-hickory forest dominated bv a canopv of & Marquis 2004). In the case of leaf ties ("sandwiches" white oak (Q. alba), black oak (O. velutina Lam.), and of overlapping leaves), there is often a high rate of sec- hickory (Carya spp.) with an understorv of flowering ondary occupation by both leaf-tying and non-leaf-ty- dogwood (Cornus florida L.), sassafras (Sassafras al- ing caterpillars (Carroll et al. 1979, Fukui 2001) result- bidum Nees), redbud (Cercis canadensis L.), sugar ing in multiple individuals of the same or different maple (Acer saccha ram Marsh) and various oak saplings. species co-occuring within a leaf tie. Such secondary The study was conducted widiin die Big Sugar Creek occupation suggests that these shelters represent a po- watershed, an unmanaged natural area of die park. tentially limiting resource for populations of leaf tiers Thirty small white oak trees (understorv saplings) and leaf tie associates and may, in part, influence the were tagged in early spring of 1996, prior to budbreak. local abundance of caterpillars occupying individual Trees ranged in height from 2 to 4 m and had at least host plants. four accessible branches randomlv assigned to one of two treatments, control and census (two branches each per tree). Leaf ties formed on census branches were 1 Current Address: George Washington University, Department of opened regularly to record die occupants whereas leal Biological Sciences, 340 Lisner Hall, 2023 G Street, NW, Washing- ton, DC 20052, USA, email: [email protected] ties on control branches were left undisturbed. The to- Journal of the Lepidoi>terists' Society New ties Abandoned ties Net ties Leaf-tying caterpillars 5/27 6/10 6/24 7/8 7/22 8/5 Census date FlG. 1. Seasonal pattern of natural leaf tie formation and leaf-tying caterpillar density on white oak. Error bars are 1 SE. tal number of leaves on each branch was recorded fol- The minimum number of total individuals and lowing budbreak. On 29 May, I established three per- species of leaf-chewing insects (caterpillars, beetles, manent artificial leaf ties on one control and one census and sawfly larvae) occupying a leaf tie over its "life- branch of each tree by clipping together haphazardly span" was determined by examining the sequence of selected clusters of three adjacent leaves with light- occupation of each natural leaf tie; consecutive records weight curler clips (one clip/three-leaf cluster; Brent- of the same species were always assumed to be a single wood Beauty Labs International, Hillside, Illinois). Ar- individual, so these estimates were likely to be conser- tificial leaf ties were created to sample the community vative. The relationship between the age of the leaf tie of secondary occupants in a standardized manner (all (expressed as the number of censuses in which it was artificial ties were initially unoccupied and established maintained) and the total minimum number of species on the same date). Beginning 29 May, the number of and individuals was examined with linear regression. all naturally occurring leaf ties present on each branch In addition, for leaf ties maintained for a given number during eight census periods (29 May, 11 June, 20 June, of censuses (3, 4, or 5), the effect of the date of tie 9 July, 23 July, 12 August, 27 August, and 14 Septem- origination on the total minimum number of species ber) was recorded. In addition, for all branches in the and individuals was examined graphically. census treatment, the contents of the leaf ties (both Because the attractiveness of leaf ties to potential natural and artificial) were recorded by briefly opening colonists might be expected to change as a tie ages (ac- the ties and then clipping them back together with a cumulating damage, frass, and silk), I examined the in- curler clip.