Inflammation in digits of unmarked and toe-tipped wild hylids

Abstract

Context The use of toe-tipping (removal of the toe pad) in mark–recapture studies of anurans is controversial because of the unknown risk of infection and potential impact on animal survival. Aims We compared the inflammation rates of digits in unmarked and toe-tipped wild hylid frogs (Litoria genimaculata, L. nannotis, L. rheocola and Nyctimystes dayi) to determine if marked amphibians present with a greater proportion of affected digits than unmarked animals. Methods We examined marked and unmarked frogs captured on streams in northern Queensland over a 12-month period for phalangeal inflammation. Key results Of 777 unmarked frogs, 0.4% presented with digits showing inflammation because of natural causes. After toe-tipping, 59.1% of the frogs were recaptured within a mean of 97 days ± standard deviation of 102 days, with macroscopic inflammation observed in 1.3% of marked animals. The proportion of marked frogs with inflamed, toe-tipped digits did not differ significantly from that of inflamed digits in unmarked frogs (Fisher exact test P = 0.085) but the odds ratio (3.417, 0.851–13.730) indicated a greater likelihood of inflamed digits occurring in toe-tipped than unmarked frogs. Conclusions Although the risk of inflammation increased 3-fold in marked hylids, the low proportion of frogs affected (1.3%) indicated the potential pathological risk of toe-tipping did not outweigh the benefits of using the marking method. Implications This study suggests that toe-tipping may be an appropriate and relatively safe marking method in stream-dwelling hylid populations.