Date of this Version
Atwell, A. 2014. Plasticity in Female Mate Choosiness: A Result of Variation in Perceived Predation Risk and the Interaction of Female Age and Male Density [thesis]. Lincoln, NE: University of Nebraska-Lincoln. 60 p.
In many species, female mate choices can be a strong source of sexual selection. Females often prefer a certain male phenotype, and this can be due to benefits females gain from mating with preferred males. However, such benefits can sometimes be outweighed by the cost of searching for a preferred male. These costs and benefits often change concomitantly with changes in environmental (e.g., predator abundance and conspecific density) and internal factors (e.g., female age). Thus, female mate choosiness (the degree to which preferences for certain males are expressed) should often be plastic. Plasticity in female mate choosiness may be complicated because environmental and internal factors may often interact naturally with one another. Therefore, it is important to understand how plasticity in mate choosiness is affected by such interactions. A small, yet growing, number of studies have investigated interactions on female mate choosiness, and have found interesting yet sometimes contradictory results. We conducted two experiments on the variable field cricket, Gryllus lineaticeps. One tested the effect of the interaction between female age (young, intermediate, and old) and male calling density (high and low), and the other tested the effect of the interaction of female age and perceived predation risk (predation chemical cues present or not) from sympatric, cursorial, wolf spider predators Hogna sp. Our results indicate a significant effect of the interaction between female age and male density, as well as a significant effect of perceived predation risk, on the plasticity of female mate choosiness. Young females exhibited the most plasticity in response to variation in male densities: young females were the most choosy in high male density environments and least choosy in low male density environments. Females, regardless of age, responded to variation in perceived predation risk the same: females were choosy when predation cues were absent, but decreased their choosiness when predation cues were present. Overall, these results suggest females who have the highest reproductive potential are the most responsive to changes in environmental and internal factors, but also that these factors can either interact with or overshadow each other to influence female mate choosiness.
Advisor: William E. Wagner, Jr.