NPB Neurobiology, Physiology & Behavior |
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| Ann Hedrick |
| Associate Adjunct Professor 1011 Life Sciences (530) 754-7611 avhedrick (at) ucdavis (dot) edu |
| Degrees: B.A., Biology, University of Virginia, 1977 M.S. Zoology, University of California, Davis, 1984 Ph. D. Zoology, University of California, Davis, 1987 Graduate Group Affiliations: Animal Behavior Graduate Group |
| Research Interests: My research program focuses on the evolution of female mating preferences, male mating behavior, and predator-avoidance behavior. I am especially interested in the interplay between sexual selection and natural selection, and in correlations between mating and other behavioral traits. My work falls into three general areas of investigation: Individual variation in mating preferences. In many animal species, females exhibit preferences for particular males as mates. Models for the evolution of female mating preferences assume that individual females within populations differ from one another in their mating preferences. However, we have a relatively poor understanding of the many factors that might influence these preferences. Therefore, one of the goals of my research program is to investigate the extent and causes of individual variation in female mating preferences. To address our research questions, we use the field cricket, Gryllus integer. In this species, males call to attract females using a rapid trill, and females prefer calls with longer durations of uninterrupted trilling (calling bouts) to those with shorter calling bouts. Calling-bout duration is a heritable trait in males. Previously I found that some females are much more selective in their call preferences than others, and that females adjust their mating decisions in response to different levels of predation risk. I am currently investigating additional sources of variation in female choice of mates. Individual and population-level variation in male mating displays. Males that use acoustic displays to attract females face an important problem: although their displays attract females, they also attract predators. Previously I found that male crickets with longer calling bouts, who are more conspicuous to predators, compensate for their increased vulnerability by acting with extra caution about predation risk. More recently we have been comparing songs and cautiousness of crickets in different populations that face different levels of predation. Male mating displays often convey multiple cues to females. A variety of hypotheses have been proposed to explain why multiple cues have evolved. To elucidate the function of multiple mating cues, we are examining additional components of courtship in male crickets (for example, chemical cues) and evaluating their roles in female choice of mates. Correlations between mating behavior and other behavioral traits. Correlations within individuals among multiple kinds of behavioral traits, such as mating behavior, predator-avoidance behavior, and foraging behavior, can limit the potential variation in an animal’s behavior on which selection can act. These correlations (“behavioral syndromes” or “animal personalities”) may therefore affect the course of behavioral evolution. However, they remain relatively unstudied in natural populations. An ongoing facet of my work is to explore behavioral syndromes associated with male calling-bout duration, a heritable trait. We are particularly interested in the links between calling behavior, predator-avoidance behavior, and fighting ability. My past work on behavioral syndromes was featured in a cover article by Susan Milius in Science News (Jan. 5, 2008). |
| Selected Publications: Kortet, R.K. & A.V. Hedrick 2007. A behavioural syndrome in the field cricket Gryllus integer: intrasexual aggression is correlated with activity in a novel environment. Biological Journal of the Linnean Society 91:475-482. Hedrick, A.V., M. Hisada & B. Mulloney. 2007. Tama-kugel: Hardware and software for measuring direction, distance and velocity of locomotion by insects. Journal of Neuroscience Methods 164:86-92. Kortet, R.K., M.J. Rantala & A. Hedrick. 2007. Boldness in anti-predator behavior and immune defense in field crickets. Evolutionary Ecology Research 9:165-197. Hedrick, A.V. & R.K. Kortet. 2006. Hiding behaviour in two cricket populations that differ in predation pressure. Animal Behaviour 72:1111-1118. Kortet, R.K. & A.V. Hedrick 2005. The scent of dominance: Female field crickets use odor to predict the outcome of male competition. Behavioral Ecology & Sociobiology59: 77-83. Hedrick, A.V. 2005. Environmental condition-dependent effects on a heritable, preferred male trait. Animal Behaviour 70:1121-1124. Kortet, R.K. & A. V. Hedrick 2004. Detection of the spider predator, Hololena nedra, by naive juvenile field crickets (Gryllus integer) using indirect cues. Behaviour 141:1189-1196. Hedrick, A.V. & B. Mulloney. 2004. A multichannel electronic monitor of acoustic behaviors, and software to parse individual channels. Journal of Neuroscience Methods 133:201-210. Hedrick, A.V., D. Perez, N. Lichti & J. Yew. 2002. Temperature preferences of male field crickets (Gryllus integer) alter their mating calls. Journal of Comparative Physiology A. 188:799-805. *Hedrick, A.V. 2000. Crickets with extravagant mating songs compensate for predation risk with extra caution. Proceedings, Royal Society of London B 267:671-675. *featured in “Editor’s Choice”, Science 288:401-403. Dill L.M., A.V. Hedrick & A. Fraser. 1999. Male mating strategies under predation risk: do females call the shots?Behavioral Ecology 10:452-461. Hedrick A.V. & T. Weber. 1998. Variance in female responses to the fine structure of male song in the field cricket, Gryllus integer. Behavioral Ecology 9:582-591. Hedrick, A.V. 1994. The heritability of mate-attractive traits: a case study on field crickets. pp. 228-250 in C. Boake, ed. Quantitative genetic studies of behavioral evolution. University of Chicago Press. Hedrick, A.V. & L.M. Dill. 1993. Mate choice by female crickets is influenced by predation risk. Animal Behaviour 46: 193-196. Riechert, S.E. & A.V. Hedrick. 1993. A test for correlations among fitness-linked behavioural traits in the spider Agelenopsis aperta (Araneae, Agelenidae). Animal Behaviour 46: 669-675. Riechert, S.E. & A.V. Hedrick. 1990. Levels of predation and genetically based anti-predator behavior in the spider, Agelenopsis aperta. Animal Behaviour 40:679-687. Hedrick, A.V. & S.E. Riechert. 1989. Genetically-based differences between populations in the foraging behavior of a spider. Oecologia 80:533-539. Hedrick, A.V. & E.J. Temeles. 1989. The evolution of sexual dimorphism in animals: hypotheses and tests. Trends in Ecology & Evolution 4:136-138. Hedrick, A.V. 1988. Female choice and the heritability of attractive male traits: an empirical study. The American Naturalist 132:267-276. Hedrick, A.V. 1986. Female preferences for male calling bout duration in a field cricket. Behavioral Ecology & Sociobiology 19:73-77. Wilson, D.S. & A.V. Hedrick. 1982. Speciation and the economics of mate choice. Evolutionary Theory 6:15-24. |