A synthesis of feeding habits and reproduction rhythm in Italian seed-feeding ground beetles (Coleoptera: Carabidae)

Many species of carabid beetles are important pre- and post-dispersal seed feeders of herbaceous plants. Here we summarise data from dissections, field observations,rearing and “cafeteria” experiments concerning the 55 granivorous and 188 omnivorous species known from Italy. We examined the hypothesis that seed feeder carabids are restricted to taxa showing pronounced morphological adaptations to seed manipulation and crushing in the larval as well as in the adult stage. The feeding guilds of carabids were rearranged into the following groups: i) strict predators with long mandibles and predaceous larvae, often depending also on non-prey food; ii)omnivorous species with stout mandibles and larvae of a seed-eating morphotype; iii)granivorous species, feeding only on seeds with larvae sometimes of the scarabeoid c-formed type. The seed feeder carabids of the Italian fauna belong to the tribes Zabrini(Amara and Zabrus genera), and to all the Harpalinae (sub)tribes, from Anisodactylinito Ditomina. The reproduction rhythm seems related to the choice between wetlands and dry open land, rather than to true granivorous versus omnivorous habits, but in stenophagous seed feeders, sometimes a phenological coincidence was found.