Sexual Selection and Parental Care in Golden Rocket Frogs

In collaboration with Mark Bee and Godfrey Bourne, Ph.D. student Beth Pettitt is leading a project that investigates the relationship between male parental care and the secondary sex traits used by females in mate choice.  While many studies have examined this relationship, most empirical tests do not adequately distinguish among current theoretical models because their findings are confounded with paternity.  Previous research has focused primarily on species with internal fertilization (e.g. avian models) in which the certainty of a male’s paternity is highly variable.  Because males are theorized to adjust the quality of their care in relation to their degree of paternity certainty, it is likely that this highly variable factor may confound the relationship between quality of care and mate signaling.  One way to eliminate this confounding effect is to examine this relationship in species exhibiting external fertilization in which egg-laying and mating occur together and paternity certainty is less variable.

The objective of this project is to provide the first comprehensive examination of the relationship between quality of paternal care and secondary sex traits used in mate choice without the confounding effects of paternity.  This project investigates this relationship in a neotropical frog (Anomaloglossus beebei) that is endemic to Guyana, South America and exhibits external fertilization as well as biparental care and acoustically mediated courtship behavior.  In so doing, the proposed research will have a greater capacity to differentiate among current theoretical models and will provide unbiased analyses leading towards a better understanding of the functional relationship between mate signaling and parental care.  The central hypothesis of this research is that variation in the acoustic properties of male vocalizations is related to the expression of male paternal behaviors and can be exploited by females to predict the quality of paternal care a male will provide.  The project will achieve the following specific aims: 1) to assess patterns of individual variation in male vocal behavior and characterize acoustically mediated female mate choice, 2) to evaluate relationships between male parental quality, male vocal behavior and fitness benefits to females, and 3) to experimentally assess fitness benefits to females mated to males with specific call traits.  Behavioral and acoustic analyses as well as playback and cross fostering experiments will be used to achieve the project’s specific aims.  The approach is innovative because it utilizes a unique combination of well-established techniques and choice of study species that allows for the elimination of the confounding effects of paternity, female parental care and offspring genetic quality.

Related Publications:

• Pettitt BA and Bee MA (in prep)  Vocal repertoire and individual identification in a neotropical frog.  For Journal of the Acoustical Society of America