Sedgwick Reserve

30 Jun, 05 PM - 16 Sep, 05 PM

In studying female mate choice, the largest focus has been on quantifying female preferences and exploring benefits of those preferences. However, just as sexually-selected traits of males are limited by natural selection, females may be limited in their mating choices if those choices bear costs. In the field cricket, Gryllus lineaticeps, both sexes are attacked by a lethal parasitoid fly. This fly locates males by their song. Though female crickets do not sing, they do become parasitized, possibly by associating with males. Because both flies and female crickets prefer higher chirp rate song, female parasitism may be a cost of associating with preferred males. Indeed, female crickets are more likely to be parasitized when in association with preferred, high chirp rate males. To determine if this association cost has affected the evolution of female cricket mating behavior, I will compare female responsiveness to male song before and during fly activity and between parasitized and unparasitized populations. Females should be more responsive to male song in areas and times where and when the flies are not present. To test if fly predation pressure has affected female responsiveness, I will run female crickets through responsiveness trials. These trials will take place in enclosed wooden arenas approximately 3 meters in length. At one end of the arena, the female cricket will be placed under a shelter and at the other end a speaker will broadcast an average male cricket call. The female will acclimate under the shelter for five minutes and then be given five minutes to respond to the male call. Females will be scored as response or no response, and I will also record the time females spend in association with the call. Several comparisons will be made to uncover any effects of fly predation on female responsiveness. First and foremost, I will compare female responsiveness between a parasitized (RSV) and an unparasitized (Sedgwick) population. This comparison will tell me if females from parasitized populations are less responsive than females from unparasitized populations. For this comparison, I will test Sedgwick females at Sedgwick and RSV females at RSV. Next, I will compare female responsiveness before and during fly activity. This comparison will tell me if females are less responsive during times of fly activity than when flies are not yet present. For this comparison, I will test RSV females at RSV before and during the fly season. I will also test Sedgwick females at Sedgwick in equivalent time periods to ensure that any changes are at least partially due to fly predation, which is not present at Sedgwick, and not something else. Lastly, I will compare responsiveness of females in their home population and in the outside population. This comparison will tell me if females are using environmental cues that alert them to the presence/absence of flies to alter their level of responsiveness, or if I see no change between locations, that the level of responsiveness is possibly an evolved response. For this comparison, I will test RSV females at both RSV and Sedgwick and Sedgwick females at both Sedgwick and RSV. Trials will be run in the enclosed wooden arenas on semi-enclosed surfaces at both sites to ensure the integrity of the populations. After a female is used once, she will be either marked with white out and returned to her home population or be sent back to the lab at UNL for use in the breeding program.

Visit #14614 @Sedgwick Reserve

Approved

Under Project # 9611 | Research

Association costs in the female variable field cricket (Gryllus lineaticeps)

graduate_student - University of Nebraska

Reservation Members(s)

Cassandra Martin Jun 30 - Sep 16, 2008 (79 days)

Reserve Resources(s) | Create Invoice

Studio Apartment 1 Jun 30 - Sep 16, 2008