Zoological Studies

Vol. 49 No. 3, 2010

Paternal Care and Egg Survivorship in a Low Nest-Attendance Rhacophorid Frog

Wei-Chun Cheng and Yeong-Choy Kam*

Department of Life Science, Tunghai University, Taichung 407, Taiwan

Wei-Chun Cheng and Yeong-Choy Kam (2010) We conducted a field study in Mar.-June 2007 to evaluate the importance of egg attendance by male Kurixalus eiffingeri to egg survivorship.  We found 38 egg clutches and visited them on a fixed scheme by checking all nests at night for 6 d, yielding 1368 visits of 10 min each.  Egg attendance frequency was highly uneven among nests and was positively correlated with clutch size.  On average, 6.8% 4.4% of eggs in an egg clutch died each day.  Daily egg mortality was inversely correlated with the attendance frequency, suggesting that paternal care is important to egg survival even though this is a low nest-attendance species.  Variances of egg mortality were low when paternal care effort was high, but opposite results were found when paternal care effort was low, suggesting the fate of eggs can also be affected by factors other than paternal care, such as stump conditions.  Our results suggest that parental care effort varies via a cost-benefit relationship of investment in the present offspring vs. future reproductive chances.  Male frogs spent more time attending eggs when the clutch sizes were large but sought additional mating opportunities if the egg clutches were small, which resulted in large variations in egg mortality among clutches.

Key words: Anuran, Nest attendance, Egg brooding, Paternal care, Rhacophoridae.

*Correspondence: Tel: 886-4-23550609.  Fax: 886-4-23550609.   E-mail:biyckam@thu.edu.tw