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ARS Home » Research » Publications at this Location » Publication #164590
Title: SPERM STRATIFICATION AND PATERNITY SUCCESS IN RED FLOUR BEETLES

Author
item LEWIS, SARA - TUFTS UNIVERSITY
item KOBEL, ANNIKA - TUFTS UNIVERSITY
item FEDINA, TATYANA - TUFTS UNIVERSITY
item Beeman, Richard

Submitted to: Physiological Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2004
Publication Date: 12/1/2005
Citation: Lewis, S.M., Kobel, A., Fedina, T., Beeman, R.W. 2005. Sperm stratification and paternity success in red flour beetles. Physiological Entomology 30: 303-307.

Interpretive Summary: Mating behavior is an important factor in understanding insect biology. Red flour beetle females are known to remate, but the question of mating frequency and preferential sperm utilization after multiple inseminations has not been adequately addressed. We used visible mutations affecting body shape to determine which progeny of individual females had been sired by various male mates. Females that had mated with three different males in succession showed a preference for sperm utilization from the most recent mating. The third mating displaced most sperm from the immediately preceding (i.e., the second) mating, but was less effective in displacing remaining sperm from the first mating. These results indicate that frequent remating is essential for reproductive success of red flour beetle males.

Technical Abstract: When females are inseminated by multiple males, male paternity success (sperm precedence) is determined by the underlying processes of sperm storage and sperm utilization. Paternity success is typically studied using two-male sperm competition experiments, but this protocol provides limited insight into more realistic scenarios when females are likely to mate with additional males. In this study, we used genetic markers in Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) to determine paternity for multiple sires and to examine temporal patterns of sperm precedence following double and triple matings. Previous studies of sperm transfer and storage in this species provide evidence that multiple matings result in sperm displacement, and this study was designed to determine whether such displacement equally affects all previous mates, or if fertilizations are disproportionately lost by the most recent mates. Over 20 days following triple matings, first males retained significantly higher paternity success (relative to first male paternity in double matings) compared to second males. Thus when females remate, sperm displacement causes differential loss of sperm from the most recent mate. These results support a model of spatial sperm stratification in multiply mated females, and suggest positional advantages for sperm utilization for both first and last mates.