Degree Name

Master of Science (MS)

Semester of Degree Completion

1989

Thesis Director

Kipp C. Kruse

Abstract

Giant waterbugs (Subfamily Belostomatinae) are interesting in that males provide exclusive post-copulatory care of young. This unusual behavior makes this species an excellent study system for investigations of sexual selection theory because in such systems, sex role reversals are predicted. Previous studies indicate that role reversal in giant waterbugs is not complete because males still court females. It is assumed that from this courtship display females can assess male quality and "choose" a superior male. If some males are chosen over others then differential mating success results. This study was undertaken to ascertain some of the factors that affect male mating success in the giant waterbug Belostoma flumineum.

Individual gravid females were given a choice between a relatively large male and a smaller male; a male with breeding experience and a virgin male; and a partially egg-laden male and a completely unencumbered male. Results suggest that size is not a good predictor of male mating success but males with previous breeding experience mated significantly more than virgin males. The latter experiment could have been confounded with age because the experienced males were also older than the virgin males used in these experiments. Finally, males that were completely unencumbered bred significantly more often than partially encumbered males. How these results fit into current sexual selection theory is discussed.

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