Content area
Full Text
J Insect Behav (2008) 21:3445
DOI 10.1007/s10905-007-9102-3
Revised: 29 May 2007 /Accepted: 26 September 2007 / Published online: 26 October 2007# Springer Science + Business Media, LLC 2007
Abstract We tested the hypotheses that postemergence experience with plants (early adult learning) modifies sex ratio and clutch size allocations of Cotesia congregata (Say) (Hymenoptera: Braconidae), a gregarious larval endoparasitoid of Manduca sexta L. (Lepidoptera: Sphingidae). Emerging wasps were exposed for 23 h to (a) one of two host plants (tomato or tobacco) or no plant, and (b) one of two novel plants (arugula or parsley) or no plant. Each female was permitted a single oviposition in a host offered with one of the two plant species 24 h later. Hosts were reared on laboratory diet before and after parasitization. Wasps exposed to either host plant allocated proportionately more females to hosts offered with the plant species experienced at emergence than wasps with the alternate species, but clutch sizes did not differ. Irrespective of plant species, wasps exposed to novel plants allocated proportionately more females to hosts than wasps without plant experience, and larger clutches to hosts offered with parsley than with arugula. Differential responses to host and novel plants suggest inherent recognition of host foodplants byC. congregata. Results demonstrate a direct effect of learning on reproductive potential.
Keywords Learning . sex ratio theory. ovipositional decision-making . tritrophic interactions . Hymenoptera . Braconidae . Cotesia congregata (Say)
Introduction
Successful reproduction in parasitic wasps begins with the location of suitable hosts for future offspring. Parasitic wasps locate potential hosts using a complex array of stimuli emanating from the host and host habitat (Vinson 1976). These stimuli include both constitutive and induced odors from host plants that can be learned by
A. J. Lentz : K. M. Kester (*)
Department of Biology, Virginia Commonwealth University, 1000 West Cary Street,Richmond, VA 23284-2012, USAe-mail: [email protected]
Postemergence Experience Affects Sex Ratio Allocation in a Gregarious Insect Parasitoid
Amanda J. Lentz & Karen M. Kester
J Insect Behav (2008) 21:3445 35
parasitoids before adult emergence (Cortesero and Monge 1994; Gandolfi et al. 2003), immediately following emergence (Kester and Barbosa 1991a), or during oviposition (Vet 1983; Turlings et al. 1993). By enhancing female responsiveness to host-linked stimuli and refining foraging skills, learning increases the...