The adaptive significance and prevalence of courtship feeding in Hawaiian swordtail crickets

dc.contributor.advisorShaw, Kerryen_US
dc.contributor.authordeCarvalho, Tagideen_US
dc.contributor.departmentBiologyen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2008-10-11T05:43:06Z
dc.date.available2008-10-11T05:43:06Z
dc.date.issued2008-06-04en_US
dc.description.abstractMales of many insect species feed their partner during courtship and mating. Studies of male nutrient donation in various systems have established that nuptial feeding has evolved mostly through sexual selection. Although there is extensive diversity in form, the function of nuptial gifts is typically limited to either facilitating copulation or increasing ejaculate transfer, depending on the time at which the gift is consumed by females. Unlike other insects, the Hawaiian swordtail cricket Laupala (Gryllidae: Trigonidiinae) exhibits serial transfer of nuptial gifts. Males transfer multiple spermless 'micro' spermatophores over several hours before mating at the end of the day (i.e. before the transfer of a single sperm-containing 'macro' spermatophore). By experimental manipulation of male microspermatophore donation, I tested several hypotheses pertaining to the adaptive significance of nuptial gifts in this system. I found that microspermatophore transfer improves insemination, by causing the female reproductive tract to take in more sperm. This result reveals a previously undocumented function for premating nuptial gift donation among insects. Enhanced sperm transfer due to microspermatophore donation may represent male manipulation or an internal mechanism of post-copulatory choice by females. I also performed experimental manipulation of male photoperiod to investigate how time and gender influence nuptial gift production and mating behavior. I found that the timing of mating is limited in males but not females and that the time of pair formation has consequences for the degree of nuptial gift donation, which suggests that both mating timing and microspermatophore number is important for male reproductive success. Finally, I observed the mating behavior of several trigonidiine taxa for a comparative analysis of sexual behavior and found that other genera also utilize spermless microspermatophores, which suggests that microspermatophore donation may be a common nuptial gift strategy among swordtail crickets. The elaborate nuptial feeding behavior of Hawaiian swordtail crickets prior to mating represents a newly discovered strategy to increase male insemination success rather than mating success. Based on this unexpected result, it is worth exploring whether courtship behaviors in other cricket or insect mating systems have also evolved to increase sperm uptake.en_US
dc.format.extent1049661 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/1903/8501
dc.language.isoen_US
dc.subject.pqcontrolledBiology, Generalen_US
dc.subject.pquncontrollednuptial feedingen_US
dc.subject.pquncontrolledsexual selectionen_US
dc.subject.pquncontrolledcricketsen_US
dc.subject.pquncontrolledmating behavioren_US
dc.subject.pquncontrolledspermatophoresen_US
dc.subject.pquncontrolledcircadian rhythmen_US
dc.titleThe adaptive significance and prevalence of courtship feeding in Hawaiian swordtail cricketsen_US
dc.typeDissertationen_US

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