PREY PREFERENCES OF CALOSOMA SYCOPHANTA L. (COLEOPTERA: CARABIDAE) LARVAE AND RELATIONSHIP OF PREY CONSUMPTION TO PREDATOR SIZE

Abstract In feeding choice tests, first- and second-instar larvae of Calosoma sycophanta L. preferred gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), pupae as prey but third-instar larvae most often consumed caterpillars. All beetle larvae preferred female pupae over male pupae. In non-choice feeding tests, older predator larvae consumed more gypsy moth fifth-instar larvae than the larger sixth-instar larvae, but the total weights of prey eaten in both cases were similar. First-instar larvae of C. sycophanta only partially consumed prey, and caterpillar size did not affect the total numbers eaten. Beetle larvae ate as many female gypsy moth pupae as male pupae, but larger larvae consumed greater weights of the former than of the latter. As a consequence, C. sycophanta larvae fed female pupae were larger than those provided with male pupae. However, for a given increase in size, third-instar larval beetles ingested the same weight of food no matter what the prey size was. Conversely, young beetle larvae seemed to require greater amounts of the body contents of large prey for a given size increase, probably because fluids from large prey were lost during predator attack. The information gained in this study may make it possible to use sizes of field-observed C. sycophanta larvae to predict numbers of prey they have killed.