, Volume 153, Issue 1, pp 197–206 | Cite as

To hatch and hatch not: similar selective trade-offs but different responses to egg predators in two closely related, syntopic treefrogs

  • Ivan Gomez-Mestre
  • Karen M. Warkentin
Behavioral Ecology


Risk-sensitive hatching is adaptive for species facing a trade-off between egg-stage and post-hatching risks, and environmental variation in one or both stages. Such plasticity has been found in amphibians, fishes, reptiles and spiders, with red-eyed treefrogs (Agalychnis callidryas) being the best-studied case. We assessed hatching plasticity and egg- and larval-stage risks in a closely related, syntopic species, the gliding leaf-frog (Agalychnis spurrelli). We found a lower hatching response to egg-eating snakes in A. spurrelli (9–28% of embryos escaped) than in A. callidryas (59–80% escaped). Levels of snake predation were similarly high for clutches of both species monitored at a pond in Costa Rica, and in fish predation experiments early-hatched A. spurrelli tadpoles were more vulnerable than later hatchlings, as has been shown for A. callidryas. A. spurrelli thus face a risk trade-off similar to A. callidryas, and likely would benefit from predator-induced hatching; their lower responsiveness to snakes appears nonadaptive. A. spurrelli embryos showed a stronger hatching response (57% hatched in 1 h) to submergence underwater than to snake attacks even though submergence is a less frequent risk. This suggests they have a greater capacity for early hatching than is expressed in the context of snake attacks, but have much lower sensitivity to snake cues than to flooding cues. Development in A. spurrelli is accelerated compared to syntopic A. callidryas, and spontaneous hatching is earlier and more synchronous. This is congruent with predictions based on selection by egg predators in the absence of a strong escape hatching response.


Embryo behaviour Hatching Inducible defence Phenotypic plasticity Predation 



We thank the staff of Sirena Biological Station, particularly P. Valverde, for logistical support in Corcovado, and U. Tigges for help monitoring egg clutches. We thank EARTH University and La Selva Biological Station for logistical support and B. Kubicki, M. Solano, and J. Pinto for assistance in Limón. We thank G. Rosenthal for comments on the manuscript, and J. G. McDaniel for conversations about biomechanics. This research was conducted under permits from the Ministerio del Ambiente y Energía, Costa Rica, and funded by the National Science Foundation (IBN-0234439 and DEB-9311196), National Geographic Society (7541–03), Ministerio de Educación Cultura y Deporte, Spain (no. EX2002-0640) and Boston University. Laboratory facilities in Sirena were made possible by an NSF grant to L. E. Gilbert.


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Department of BiologyBoston UniversityBostonUSA

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