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.