Nocturnal foraging and activity by diurnal lizards: Six species of day geckos (Phelsuma spp.) using the night-light niche

Altered environments in urban areas are known to impact and change animal behaviour. In particular, artificial light at night (ALAN) affects behaviour across taxonomic groups, including reptiles. Geckos in the genus Phelsuma are predominantly diurnal, but some have been documented to alter their foraging behaviour from a diurnal to nocturnal activity period when they have access to artificial light sources. Herein, we report new observations of six Phelsuma spp. (Andaman day geckos, P. andamanensis; blue-tailed day geckos, P. cepediana; Madagascar giant day geckos, P. grandis; Reunion ornate day geckos, P. inexpectata; gold dust day geckos, P. laticauda; Mahe day geckos, P. sundbergi longinsulae) using artificial lights to engage in nocturnal activity that includes foraging, courtship, and agonistic behaviour. Artificial light at night augments the amount of time predators, especially visual predators, can spend foraging. This can increase their overall daily activity period (i.e. the amount of time spent active within 24 h), and research is yet to fully understand the cost-benefit trade-offs this altered behaviour has on individual fitness. Overall, our novel accounts of six Phelsuma spp. contribute to knowledge regarding the diversity of animals that have altered their behaviour in response to ALAN and highlight the behavioural flexibility of this group of geckos.