Jennifer M. Gumm
Ph.D. Candidate
Lehigh University
Department of Biological Sciences
111 Research Drive
Bethlehem, PA 18015
Research Interests
I am currently completing my Ph.D. in Integrative Biology in the laboratory of Murray Itzkowitz at Lehigh University. My training in behavioral ecology and evolution is reflected in my research on behavioral interactions and communication within a phenotype, between phenotypes and between species. Specifically, I am interested in sexual selection, the evolution of communication and how related behaviors can lead to change between populations and species.
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My dissertation research explores the roles of communication and reproductive behavior in the evolution and maintenance of male alternative reproductive tactics in the Comanche Springs pupfish, Cyprinodon elegans. I use laboratory experiments to examine how communication mediates interactions between males expressing the same reproductive tactic (‘dear enemy recognition’), while also performing manipulative field experiments to examine communication among males expressing alternative reproductive tactics (sex recognition of female mimics). Interactions among males expressing alternative mating tactics may have important evolutionary consequences in fitness and I am completing the first genetic study of the mating system in this genus of fishes. Combining behavioral observations with microsatellite-based parentage analyses, I am examining how direct effects of male behavior related to alternative reproductive tactics result in variation in reproductive success.
Additional research projects
Conflicts and conservation between endangered desert fishes
Over the past 6 years there has been a population decline in the single remaining natural population of the endangered Leon Springs pupfish, Cyprinodon bovinus. Murray Itzkowitz, Jen Snekser and I examined interactions between C. bovinus and a heterospecific egg predator, Gambusia nobilis. Our results suggest that G. nobilis presence at spawnings may be playing a role in the decline of C. bovinus. Further, the high cost posed by intruding G. nobilis may alter the evolutionary dynamics of C. bovinus breeding tactics (Gumm et al. in revision).
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The conservation of naturally sympatric endangered species requires unique considerations and management of interactions between endangered species has garnered little attention. Our initial study led to a project funded by the Texas Parks and Wildlife to carry out habitat restoration in the natural population of C. bovinus. Additionally, I worked in cooperation with the Dexter National Fish Hatchery and Technology Center in New Mexico to conduct a genetic analysis of this small, endangered population.
Association preferences of fin-mutant female zebrafish (Danio rerio)
Females often choose to associate with males that have exaggerated traits. In fishes, this may reflect an overall preference for larger size in a potential mate. Female zebrafish (Danio rerio) prefer males with larger bodies but not longer fins. The availability of mutant and transgenic strains of zebrafish make this a unique model system in which to study the role of phenotypic variation in social and sexual behavior. Jen Snekser, Kathy Iovine and I used mutant strains of zebrafish with truncated (short fin) and exaggerated (long fin) fins to further examine female preferences for fin length in dichotomous association tests. Mutant phenotypes differed in their preferences for longer fins, suggesting that mutations resulting in altered fin morphological may also be involved in a related female association preference (Gumm et al., submitted)
Behavioral trade-offs by male Beaugregory damselfish (Stegastes leucostictus)
Beaugregory damselfish live in shallow back reef areas where males defend territories around female spawning sites. Within their territories, males direct courtship behaviors (a dipping behavior associated with a dramatic color change) to females and also fight and chase away male conspecific intruders. Santangelo et al. (2004) found that males were more likely to be aggressive to an intruding male over court a nearby female. In the summer of 2005, Murray Itzkowitz, Matt Draud, Natalie van Breukelen and I expanded this work to examine how distance can alter a males’ decision to fight or court (Gumm et al. in prep).
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Pair bond formation and breeding site limitation in convict cichlids
Convict cichlids (Archocentrus nigrofasciatus) form pair bonds, are serially monogamous, and give bi-parental care to their offspring. Males and females may individually establish a breeding site before courtship or they may form a pair and then obtain a breeding site together. Such sites are important resources for convict cichlids, and their availability often limits reproduction. We examined if variation in breeding site availability affected pair bonding between males and females and aggressive behaviors between bonded pairs. We found that pair bonds rarely formed when no breeding sites were provided; however, pair bond formation was not limited by breeding site number when at least one breeding site was available. In addition, there were no differences in aggression by paired individuals after breeding site manipulation, perhaps indicating that changes in the subsequent availability of breeding sites after pair formation did not influence a pair’s aggression (Gumm & Itzkowitz 2007).
Species and mate quality recognition in mollies
For my Masters work at Texas State University, I worked with Caitlin Gabor examining mate quality and species recognition in a bisexual/unisexual species complex of mollies. Male sailfin mollies (Poecilia latipinna) mate with females of their own species as well as with Amazon mollies. Amazon mollies (P. formosa) are unisexual gynogens: they require sperm from males to start the process of embryogenesis but use none of the males DNA and essentially clone themselves. Males get no obvious benefits from mating with Amazons and their persistence is an evolutionary paradox. I examined a conflict between size as a mate-quality cue and species recognition cues used by males as a possible way for Amazons to garner matings (Gumm & Gabor 2005). In addition, I examined the specific visual cues male sailfin mollies may be using to tell the difference between female sailfin and Amazon mollies by making models that isolate individual visual cues (Gumm et al. 2006).
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Pre-existing biases by a unisexual species, Poecilia formosa
Unisexual females that reproduce by gynogenesis are not expected to express preferences for certain males, as they do not gain direct or genetic benefits from these males. However, they may exhibit preferences for some males because of mechanisms that rely on exploitation of female sensory systems as predicted by the ‘pre-existing bias’ hypothesis or via inheritance of mate preferences from parental species. The unisexual, gynogenetic Amazon molly (Poecilia formosa) is a hybrid of the Atlantic molly (P. mexicana) and sailfin molly (P. latipinna). The two parental species differ in their pre-existing bias in preference for sword tails on males. Maria Thaker and I further examined the variation in pre-existing bias within this species complex by testing Amazon molly preference to associate with males and females sailfin mollies, P. latipinna, with artificially attached swords (Gumm & Thaker, submitted).
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Publications
- Gumm, J. M. and Gabor, C. R. 2005. Asexuals looking for sex: Conflict in species and mate-quality recognition in Poecilia latipinna (Poeciliidae). Behavioral Ecology and Sociobiology: 58, 558-565.
- Gumm, J. M., Gonzalez, R., Aspbury, A. S. and Gabor, C. R. 2006. Do I know you? Species recognition operates within and between the sexes in a unisexual- bisexual species complex of mollies. Ethology: 112, 448-457.
- Gumm, J. M. and Itzkowitz, M. 2007 Pair bond formation and breeding site limitation in convict cichlids. Acta Ethologica. 10: 29-33
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In prep or in review:
- Gumm, J. M., Snekser, J. L. & Itzkowitz, M. Conflicts and conservation between endangered desert fishes. In revision.
- Gumm, J. M. & Thaker, M. Differential responses to swords by unisexual Amazon mollies (Poecilia formosa). Submitted to Behaviour, June 2008
- Gumm, J. M., Snekser, J. L. and Iovine, M, K. Association preferences of fin-mutant, female zebrafish, Danio rerio. Submitted to Behavioural Processes, July 2008
- Gumm, J. M., van Breuklen, N. A., Draud, M. & Itzkowitz, M. Distance influences a behavioral trade-off in the beaugregory damselfish (Stegastes leucostictus). In preparation
Links
Coming soon!