Wednesday, 20 November 2002

This presentation is part of : Display Presentations, Subsection Cd. Behavior and Ecology

Host plasticity, respiration rate and the outcome of larval competition in the cowpea weevil

Raul Narciso C. Guedes1, Robert H. Smith2, and Nelsa Maria P. Guedes2. (1) Universidade Federal de Vicosa, Departamento de Biologia Animal, Campus Universitario, Vicosa, Minas Gerais, Brazil, (2) University of Leicester, Department of Biology, Environmental Biology Group, Adrian Building, University Road, Leicester, United Kingdom

Variation between strains of Callosobruchus maculatus in several life-history traits is well known. Differences in functional anatomy of egg pores and larval respiration rates have also been reported in strains from Brazil and Yemen. The plasticity of response of five strains of C. maculatus reared on seeds of two host species, cowpea (Vigna unguiculata) and mung bean (V. radiata), was measured along with the larval respiration rates of the same strains on both hosts. There was significant plasticity of response on the two hosts. The larval respiration rate (ml O2/insect/day) was correlated with grain consumption (mg) per adult emerged. High grain consumption was associated with low adult emergence when comparisons were made across strains reared on the two different hosts. This finding provides support for the hypothesis that differential feeding rate is an important mechanistic component of the larval competition outcome observed in strains of C. maculatus.

Species 1: Coleoptera Bruchidae Callosobruchus maculatus (southern cowpea weevil, cowpea weevil)
Keywords: phenotypic plasticity, vigna

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