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EDUCATION

1993  B.S.  Ball State University

1998  M.S.  Ball State University

2002  Ph.D.  University of Dayton

RESEARCH INTERESTS

Avian ecology, sexual selection in socially monogamous species, use of multiple ornaments in sexual selection, use of ultraviolet reflectance in communication, maternal effects, mechanisms of ornament production (particularly melanogenesis), application of behavioral ecology to conservation biology

CURRENT RESEARCH

My current research program has two focuses; (1) female ornamentation as it indicates maternal effects and intrasexual aggression and (2) the hormonal influences on intrasexual aggression in females. 

My research into maternal effects and whether the level of maternal effects displayed are indicated by ornamentation uses the northern cardinal (Cardinalis cardinalis) as a focus species.  Female cardinals possess multiple ornaments that are indicative of a variety of aspects of condition (Jawor et al., in press).  Additionally, cardinals mate assortatively by multiple ornaments (Jawor et al. 2003), and female cardinals perform unique displays of their ornamental characters (Jawor and Breitwisch, in press).  These findings suggest that female ornaments in cardinals are assessed during pair formation and that males may make mate choice decisions based on female ornament expressions (see T. Amundsen, 2000, TREE for a review of female ornamentation and its use in sexual selection). 

 Maternal effects are, typically, non-genetic influences of a female’s phenotype on the quality of the offspring she produces.  Maternal effects in birds can be influenced by the amount of steroid hormones and carotenoids deposited in eggs during oogenesis.  Circulating steroid hormones and carotenoids also influence ornament expressions in adults, making it possible that ornaments in females can indicate the level of these components in eggs that they will produce.  This, in turn, may influence male mating decisions and, ultimately, the evolution of female ornamentation and egg components.

 My research into female intrasexual aggression and the hormonal influences of aggression uses the dark-eyed junco (Junco hyemalis) as a focus species.  During the non-breeding season juncos live in large flocks in which a dominance hierarchy is maintained.  Birds of higher dominance benefit by having access to more food resources, better roosting locations, and safer roosting and foraging locations.  In setting up dominance hierarchies individuals interact aggressively with one another.  This occurs at a time (non-breeding season) when circulating steroid hormones are low and may not have a strong influence on behavior.  One hormone, corticosterone (typically considered a stress hormone) may influence the behavior of individuals as they compete for access to resources (e.g., food) within the flock.  Additionally, DHEA may also influence aggressive behaviors in the non-breeding season. 

REFEREED PUBLICATIONS

[1] Jawor, J.M., Young, R., & Ketterson, E.D.  2006.  Females competing to reproduce: dominance matters but testosterone may not. Hormones and Behavior 49:362-368.

[5] Jawor, J.M., Linville, S.U., Beall, S.M. & Breitwisch, R.  2003.  Assortative mating by multiple ornaments in northern cardinals (Cardinalis cardinalis). Behavioral Ecology 14:515-520.