Risk of Sperm Competition Mediates Copulation Duration, but not Paternity, of Male Burying Beetles

Males in many taxa are known to exhibit behavioural plasticity in response to the perceived intensity of sperm competition, reflected in Drosophila melanogaster by increased copulation duration following prior exposure to a rival. We tested the prediction that males do not adjust their copulation effort in response to the presence of a competitor in Drosophila species where there is little or no sperm competition. Contrary to expectations, male plasticity in copulation duration was found in both Drosophila subobscura and Drosophila acanthoptera , species in which females rarely remate. These results are discussed in relation to the adaptive basis of plasticity in these species.

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MOLECULAR GENETIC ANALYSIS OF REMATING FREQUENCIES AND SPERM COMPETITION IN THE SCORPIONFLY PANORPA VULGARIS (IMHOFF AND LABRAM)

Behaviour ◽

10.1163/156853999501784 ◽

1999 ◽

Vol 136 (9) ◽

pp. 1107-1121 ◽

Cited By ~ 24

Author(s):

Thomas Gerken ◽

Jorg Thomas Epplen ◽

Afra Schmidt ◽

Klaus Peter Sauer Conny ◽

Iris Over ◽

...

Keyword(s):

Sperm Competition ◽

Microsatellite Loci ◽

Mating Systems ◽

Molecular Genetic ◽

Molecular Genetic Analysis ◽

Copulation Duration ◽

Selective Force ◽

Microsatellite Typing ◽

In Captivity ◽

Polymorphic Microsatellite

AbstractSperm competition can be a powerful selective force in the evolution of mating systems. The level of sperm competition depends on the remating frequency of females. Several scorpionfly species have been studied with respect to their mating systems. However, remating frequencies and lifetime patterns of sperm usage are completely unknown. Members of the genus Panorpa (Panorpidae: Mecoptera) display a particularly interesting range of mating systems, and Panorpa vulgaris was selected for study. Remating frequencies of wildcaught females were estimated (a) by comparing sperm quantities in females caught early and late in the season with mean number of sperm transferred by males in one copulation, and (b) by polymorphic microsatellite loci. The paternity of offspring produced during the entire lifetime of females in the lab was determined using three polymorphic microsatellite loci. More than 1200 individuals, collected both from wild and from captivity-bred P. vulgaris , were typed for paternity analyses. Microsatellite typing as well as comparison of sperm quantities showed (1) that females mated with several males and (2) that the number of mates increased with progressive lifetime. Some females were observed in captivity during their entire lifetime and the complete mating activities were recorded. Analysis of their offspring showed that females allocate paternity in proportion to male copulation duration. Remating and sperm mixing may allow females to gain "high quality" genes for their offspring when females adjust copulation duration to male quality.

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Ejaculate size variation in the migratory locust, Locusta migratoria

Behaviour ◽

10.1163/156853903321826657 ◽

2003 ◽

Vol 140 (3) ◽

pp. 319-332 ◽

Cited By ~ 7

Author(s):

Debora Arlt ◽

Klaus Reinhardt

Keyword(s):

Sperm Competition ◽

Locusta Migratoria ◽

Good Condition ◽

Size Variation ◽

Copulation Duration ◽

Female Size ◽

Testis Weight ◽

Migratory Locust ◽

Ejaculate Size ◽

Older Males

AbstractSperm competition models suggest that ejaculate size (ES) is adjusted in relation to female fecundity and the risk of sperm competition, depending on the information males have about that risk. We tested these ideas in the migratory locust, Locusta migratoria, a species in which ES may be an important male fitness parameter. Copulation duration was positively correlated with ES. Males did not increase copulation duration but sperm transfer in the presence of competitors during mating. They did so only when they were reared in conditions that allowed female perception prior to mating. Males that prior to mating were kept with other males only did not show ES variation with regard to different sex ratios at mating. Increased female availability did not affect ES. A male size and condition related parameter was not significantly correlated to ES but older males delivered smaller ejaculates. Females of larger size were inseminated larger amounts of sperm. There was a positive correlation between female size and ES only for males of lower condition and lower relative testis weight but not for males of good condition or higher relative testis weight.

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