Diet analysis of Homonota darwini (squamata:gekkonidae) in northern patagonia

KUN MARCELO, CARLA PIANTONI, JOHN D. KRENZ, NORA R. IBARGUENGOYTIA

CURRENT ZOOLOGY

Current Zoology

Año: 2010 p. 406 - 410

1674-5507

 Herein we describe the diet of the southernmost gecko in the world, Homonota darwini. Fifty-two specimens were captured in four locations in Patagonia, Argentina, in spring and summer and their stomach contents were identified. The prey consisted primarily of six groups: Coleoptera, Hymenoptera, Homoptera and Araneae, and the adults and larvae of moth Lepidoptera. Major contributions to the diet of Homonota darwini were Lepidoptera. The observation of ants and moths as common prey suggests an ambush feeding strategy. In spring, females consumed more ants than males although no other dietary differences between males and females were evident. We found nine geckos with empty stomachs and six parasitized by nematodes. Presence of empty stomachs corroborates previous observations of other nocturnal geckos and non-gecko lizards. Reduced foraging success of nocturnal lizards suggests the difficulty of detecting prey in dim light, reduced or erratic activity of insect prey at night, or shorter activity times of geckos relative to diurnal success. Neither sex nor season was associated with the incidence of empty stomachs.  Principal component analysis shows that four food alternatives correlated with season. The constraint of nocturnality, coupled with low night-time temperatures that restrict feeding until only a few hours following sunset, appears to cause a generality of diet and may limit energy acquisition. We conclude that H. darwini is an arthropod generalist and is likely an ambush forager as are many other nocturnal gekkonids.