The Adaptive Significance of Egg Attendance in a South-East Asian Tree Frog



David P. Bickford, Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Block S3, Singapore 117543.



The arboreal frog, Chiromantis hansenae (Family: Rhacophoridae), is one of only a handful of South-East Asian amphibian species reported with parental care. We present the first systematic observational and experimental study confirming offspring benefits as a result of this care, which has a number of unusual life-history characteristics. Eggs are unusually small, breeding takes place in large pools, and females attend the eggs. Field observations and an adult removal experiment demonstrated a critical contribution of egg attendance to offspring survivorship. Harsh environmental conditions for offspring appeared to be the prime mover of parental care in this species, with desiccation as the main source of mortality when attending adults are absent. Results confirm females to be the caregivers, making C. hansenae a rare case of maternal egg attendance in a non-directly developing anuran.