SREL Reprint #2900

Experimental evidence that nest attendance benefits female marbled salamanders (Ambystoma opacum) by reducing egg mortality

Dean A. Croshaw1,2 and David E. Scott1

1Savannah River Ecology Laboratory, Drawer E, Aiken, South Carolina 29802
2Department of Zoology, University of Oklahoma, Norman 73019

Abstract: To understand the selective pressures that have influenced the evolution and maintenance of parental care, it is necessary to assess the consequences and function(s) of specific behaviors. We used field and laboratory experiments to investigate possible fitness benefits and proximate functions of female nest attendance in marbled salamanders (Ambystoma opacum). In the first field experiment, nests at which females remained until flooding had higher hatching success than those without attendant females, but results were somewhat equivocal. In the second field experiment we used unattended eggs in artificial clutches randomly assigned to one of four treatment groups: eggs physically agitated to possibly reduce developmental malformations and/or fungal growth, eggs protected from predators, eggs moistened by addition of water and eggs in an unmanipulated control group. Clutches that were protected from predators had significantly higher hatching success than control, agitation and supplemental water groups. In the laboratory experiment, nests in which fungal infection was controlled had higher hatching success than those without sterilized substrates. Also, physical agitation and increased moisture did not confer higher hatching success when fungi were eliminated in the laboratory. Predation and fungal infections appear to decrease hatching success in this species, and female nest attendance may reduce these risks.

SREL Reprint #2900

Croshaw, D. A. and D. E. Scott 2004. Experimental evidence that nest attendance benefits female marbled salamanders (Ambystoma opacum) by reducing egg mortality. The American Midland Naturalist 154:398-411.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).