Feeding, Oviposition, and Aggregation by the Rusty Grain Beetle, Cryptolestes ferrugineus (Coleoptera: Cucujidae) on Seed-Borne Fungi1

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Abstract
Twenty-three species of fungi and 1 actinomycete cultured on potato-sugar-agar slants were tested as feeding media and oviposition sites for the rusty grain beetle, Cryptolestes ferrugineus (Stephens). The best fungi for feeding and oviposition were Nigrospora sphaerica, Mucor sphaerosporus, Hormodendrum cladosporioides , and Curvularia tetramera . Different species within the same genus elicited different responses; Penicillium cyclopium and P. funicnlosum were moderately satisfactory for feeding and oviposition while P. terrestre was unsatisfactory. Beetles fed moderately but apparently did not oviposit on Aspergillus flavus . They fed slightly and laid few eggs on A. fumigatus . No eggs and only traces of feeding were observed on A. niger, A. ochraccous , and A. versicolor , and on the actinomycete Streptomyces griseus . Aggregation on wheat kernels infected with the fungus N. sphaerica was observed in 2-choice experiments. Beetles aggregated in large numbers and fed extensively on kernels infected with mycelia and spores of N. sphaerica . The strongest aggregating and feeding responses were evoked by damp, fungus-infected kernels with exposed germs. After consuming the fungus, beetles frequently ate the germ portion of the kernel. The presence of N. sphaerica was the most important single factor influencing response. Uninfectal kernels with exposed germs induced larger aggregation;; and more feeding activity than those with unexposed germs.

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