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Nutrient Effects on Sexual Selection and Comparison of Mating Calls in Katydids (Tettigoniidae)

Trozzo, Lara Rae
http://rave.ohiolink.edu/etdc/view?acc_num=kent1366305559

Abstract Details

2013, MS, Kent State University, College of Arts and Sciences / Department of Biological Sciences.
Male katydids produce mating calls through stridulation to attract potential mates. Calls were recorded in the field and analyzed to compare between two related species that occur in overlapping ranges in the northwestern United States. Distinct differences were found between the two species' calls in both dominant frequency and chirp rate. Also, one species interspersed trills amongst the chirps of the call, while the other species' call did not include trills. These distinct call differences can be used for species identification and can be easier to differentiate than physical characteristics. The upper limits of sexual selection can be estimated using upper limits on Bateman gradients, which represent how fecundity increases with additional mates. Upper limits on Bateman gradients are expected to be constrained by various factors such as nutrition. These upper limits were estimated using controlled mating experiments with katydids on high and low protein diets (as adults) by measuring how maximum fecundity (fecundity with ideal mates) increased with each mating. Decreases in both maximum fecundity and the potential for sexual selection were expected in males and females due to protein limitation. This would result from decreased potential fecundity in low protein females and decreased value of nuptial gifts given by low protein males. The results did not support our predictions as strongly as hoped, but a decrease in the upper limits of sexual selection was nearly significant in low protein males, evidenced by reduced fecundity gains from remating. Also, spermatophores (the katydid nuptial gift) had a more complicated effect on fecundity than expected. Spermatophore size differed between males' first and second matings, however, larger spermatophores did not always confer more value to females, particularly in second matings. Stable isotope analysis was used to examine the lack of significant effects from differences in dietary protein on the upper limits of sexual selection in the previous experiment. Stable isotope ratios were analyzed for three body tissues to infer diet at different life stages by comparison with isotopic values from the foods. Results showed that animals on the low protein diet may have eaten more food to make up for their protein deficit, which would have confounded nutritional effects in the previous study. Sex differences in nutrient processing were present as would be expected if males and females experience different nutritional requirements for reproduction. Nutrient processing in exoskeleton varied across food treatments in males but not in females. This suggests that males experienced greater protein limitation than females and adjusted their nutrient processing accordingly. Further work is underway to determine how much of each type of food was consumed by individuals in different experimental treatments and during different life stages.
Patrick Lorch (Advisor)
Mark Kershner (Committee Member)
Sean Veney (Committee Member)
68 p.
Animal Sciences; Animals; Behavioral Sciences; Behaviorial Sciences; Biology; Ecology; Entomology; Evolution and Development; Organismal Biology; Zoology
sexual selection; katydid; Orthoptera; Conocephalus; mormon cricket; Bateman gradient; animal behavior; nutrient; nutrient processing; stable isotope; mating call; Tettigoniidae; spermatophore; nuptial gift; mate choice; mate preference; mate condition

Recommended Citations

Citations

  • Trozzo, L. R. (2013). Nutrient Effects on Sexual Selection and Comparison of Mating Calls in Katydids (Tettigoniidae) [Master's thesis, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1366305559

    APA Style (7th edition)

  • Trozzo, Lara. Nutrient Effects on Sexual Selection and Comparison of Mating Calls in Katydids (Tettigoniidae). 2013. Kent State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1366305559.

    MLA Style (8th edition)

  • Trozzo, Lara. "Nutrient Effects on Sexual Selection and Comparison of Mating Calls in Katydids (Tettigoniidae)." Master's thesis, Kent State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1366305559

    Chicago Manual of Style (17th edition)

kent1366305559
545
© 2013, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.