PROC. ENTOMOL. SOC. WASH. 104(2), 2002, pp. 437-446 CONSTRUCTION OF A DEFENSIVE TRASH PACKET FROM SYCAMORE LEAF TRICHOMES BY A CHRYSOPID LARVA (NEUROPTERA: CHRYSOPIDAE) Thomas Eisner, James E. Carrel, Eileen Van Tassell, E. Richard Hoebeke, and Maria Eisner (TE, ME) Department of Neurobiology and Behavior. Cornell University, Ithaca, NY 14853, U.S.A. (e-mail:
[email protected];
[email protected]); (JEC) Division of Biolog-ical Sciences, University of Missouri, Columbia, MO 65211, U.S.A. (e-mail:
[email protected]); (EVT) Department of Entomology, Michigan State University, East Lansing, MI 48824, U.S.A. (e-mail:
[email protected]); (ERH) Department of Entomology, Cornell University, Ithaca, NY 14853, U.S.A. (e-mail:
[email protected]) Abstract. — The behavior of a chrysopid larva from Arizona is described, identified as Ceraeochrysa lineaticornis (Fitch), which constructs its trash packet from the trichomes of sycamore leaves {Platamis wrightii S. Watson). The trichomes are particularly dense on the underside of the leaves. To fashion the packet, the larva uses trichomes stuck loosely to the leaf, and others that it plucks from the leaf surface. The packet on the mature larva weighs on average 2.2 mg, an equivalent of approximately two leaf under-sides worth of trichomes. Evidence is presented indicating that the packet provides the larva with protection against predation. It is argued that the trichomes are defensive in the sycamore tree itself, and that the chrysopid provides yet another example of an insect that benefits from utilization of a plant defense. Interestingly, the chrysopid benefits the sycamore tree itself. Although it usurps the tree's defense, it aids the tree by preying on a specialist herbivore, the tingid, Coiythucha confraterna Gibson, which feeds on the sycamore tree unbothered by the trichomes. Key Words: animal defense, Neuroptera, Chrysopidae, Ceraeochrysa lineaticornis, plant defense, trichome, insect-plant interaction Many chrysopid larvae have the habit of tion against insectan predators (New 1969, collecting exogenous materials and placing Principi 1946, Eisner et al. 1978). Not all them on their backs, forming so-called trash chrysopid larvae are trash carriers, but packets that they retain throughout larval those that are, are obligatorily so, and the life (Smith 1922, Canard et al. 1984). The priority that larvae give to forming trash materials they use to fashion the packets are packets has a significant genetic component variable and may consist of vegetable mat-(Milbrath et al. 1993, Tauber et al. 1995). ter, arthropod remains, insect waxes, or Here we describe the behavior of a chry-general debris (Smith 1922, Slocum and sopid larva that constructs its packet from Lawrey 1976, New 1969, Eisner et al. trichomes that it takes from the leaves of 1978, Canard et al. 1984). Existing evi-sycamore trees (Platanus wrightii S. Wat-dence indicates the packets act as physical son) in Arizona. We present data on the shields that provide the larvae with protec-feeding habits of the larva, as well as on
BioStor
