The ecology of parental care in a terrestrial breeding frog from New Guinea

Summary

Cophixalus parkeri is a terrestrial breeding microhylid frog from the montane moss forests of northeastern New Guinea. The pattern of parental care in this species and its adaptive significance was studied in the field and in the laboratory. Egg brooding, is performed by the male in most cases, and much less frequently by the female. The parent remains with the clutch throughout the 85–100 day prehatching period. Egg removal experiments demonstrated that survivorship of embryos significantly decreased in the absence of the attending parent. Mortality of unattended embryos may be caused by a variety of factors, including fungal infection, egg cannibalism, predation by arthropods, and abnormal development.

Brooding adults can provide protection to their developing offspring via several possible mechanisms eg. aggressive defense of territories on which eggs are deposited, ingestion of potential arthropod predators, and egg turning (Fig. 2).

Several differences were found in the quality and quantity of food ingested by brooding versus non-brooding adults collected in the same locality during the same period. On average, brooding adults consumed less food and of lower quality than non-brooding adults (Table 1). These differences in diet were correlated with length of time parents had attended their eggs before they were examined (Fig. 3). The reduced food intake during egg brooding is reflected by significantly smaller fat bodies and less carcass fat in egg brooders relative to nonbrooding adults (Table 1). These results are discussed in terms of relative costs and benefits of parental care in this species.