Laboratory studies of predatory behaviour in two subspecies of the Carabid cave beetle: Neaphaenops tellkampfi

Comparative studies on the foraging behaviour of Neaphaenops tellkampfi tellkampfi and N. t. meridionalis demonstrated adaptation to different environments. The southern subspecies N. t. meridionalis, which is found in wet muddy caves where cave cricket eggs are unlikely prey, did not locate buried cricket eggs and dug fewer and less accurate holes in the lab than the nominate subspecies. N. t. tellkampfi, which reaches high densities in sandy deep cave environments where cricket eggs are the only viable prey, gained significantly greater weight than meridionalis when presented buried cricket eggs as prey. There was no difference with respect to weight change between the subspecies in the presence of Ptomaphagus larvae. N. t. meridionalis gained weight at a significantly greater rate than the nominate subspecies with enchytraeid worms as prey. Enchytraeid worms represent the natural prey most likely to be encountered by N. t. meridionalis. 25% of beetle holes were dug deep enough to potentially located buried cricket eggs. Since Hubbell and Nortons’ morphological data on the relationship between cricket ovipositor length and beetle predation have some problems with sample sizes and minor assumptions I conclude that there are no unequivocal data that support the possibility of coevolution between Neaphaenops and Hadenoecus