Pizzari, T, Birkhead, TR. Female feral fowl eject sperm of subdominant males. Nature, 405: 787-789
Department of Animal and Plant Sciences, University of Sheffield, UK.Nature (Impact Factor: 41.46). 07/2000; 405(6788):787-9. DOI: 10.1038/35015558
Paternity is often determined by competition between the ejaculates of different males. Males can also use particular behaviours or structures to manipulate how females use sperm. However, the ability of females to bias sperm utilization in favour of preferred males independently of male manipulation has not been demonstrated. Females are predicted to respond differentially to the sperm of different males when the reproductive interests of the sexes differ and when females are coerced into copulating. Here we show that in female feral fowl most copulations are coerced, and that females consistently bias sperm retention in favour of the preferred male phenotype. Females prefer to copulate with dominant males, but when sexually coerced by subordinate males, they manipulate the behaviour of dominant males to reduce the likelihood of insemination. If this fails, females differentially eject ejaculates according to male status in the absence of any male manipulation and preferentially retain the sperm of dominant males.
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- "Convincing positive associations of sperm dumping with particular male traits have been established in few species. The traits include male social dominance in birds (Pizzari and Birkhead 2000) and the sizes and movements of genital sclerites in insects (Córdoba-Aguilar 2006; Rodríguez et al. 2004). Females of P. globosus (Pholcidae) often emit a mass of sperm in an irregular white mass from the female's genitalia near the end of the copulation, or just following copulation (Huber and Eberhard 1997) (Fig. 5.3). "
ABSTRACT: Cryptic female choice (CFC) in spiders may involve several mechanisms to bias paternity including early termination of copulation, remating likelihood, and sperm dumping. In Pholcidae, these mechanisms seem to be very common and will be examined in the present chapter. In the Pholcidae Physocyclus globosus, sperm dumping involves an active role of the female. In contrast, in the Pholcidae Holocnemus pluchei, sperm mass ejection during copulation is mainly under male control. In another haplogyne spider, the Oonopidae Opopaea fosuma, females are able to influence male's chances of rearing their offspring by also exerting CFC by sperm dumping. Among pholcids, rhythmic genitalic movements of the pedipalps (squeezes) during copulation have been interpreted as genitalic copulatory court-ship. Additionally, recent studies have evaluated the possibility that the outcome of male–female copulatory communication affects paternity. Future attention to the behavior of both female and male, and to the possible dialogues during copulation, promises to be a valuable tool in understanding sexual interactions in these spiders.
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- "For example, female scorpionflies, Harpobittacus nigriceps, adapt their remating rate according to the size of the nuptial gift received during the first mating (Thornhill, 1983). In the feral fowl, Gallus gallus, females are more likely to eject sperm after mating with a subordinate, than after mating with a dominant male (Pizzari & Birkhead, 2000). Female black field crickets, "
ABSTRACT: After choosing a first mate, polyandrous females have access to a range of opportunities to bias paternity, such as repeating matings with the preferred male, facilitating fertilization from the best sperm or differentially investing in offspring according to their sire. Female ability to bias paternity after a first mating has been demonstrated in a few species, but unambiguous evidence remains limited by the access to complex behaviours, sperm storage organs and fertilization processes within females. Even when found at the phenotypic level, the potential evolution of any mechanism allowing females to bias paternity other than mate choice remains little explored. Using a large population of pedigreed females, we developed a simple test to determine whether there is additive genetic variation in female ability to bias paternity after a first, chosen, mating. We applied this method in the highly polyandrous Drosophila serrata, giving females the opportunity to successively mate with two males ad libitum. We found that despite high levels of polyandry (females mated more than once per day), the first mate choice was a significant predictor of male total reproductive success. Importantly, there was no detectable genetic variance in female ability to bias paternity beyond mate choice. Therefore, whether or not females can bias paternity before or after copulation, their role on the evolution of sexual male traits is likely to be limited to their first mate choice in D. serrata.
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- "a male-female contest which may be costly for the male as well as the female, and may either attract the attention of rival males, thus triggering a male-male contest (Clutton-Brock and Parker, 1995), or render both parties more vulnerable to predation (Evans et al., 2003; Griffiths et al., 2004; Magurran and Nowak, 1991). Copulation, moreover, is only a means to fertilization and without long-term influence over the female, a coercive male's fertilization prospects are more vulnerable to female counter-tactics such as copulation with alternative males (Emlen and Wrege, 1986) or sperm ejection (Pizzari and Birkhead, 2000). Coercion may, nevertheless, be the only option for subordinate males who are attempting to make the most of a bad situation. "
ABSTRACT: Sexual coercion by males is generally understood to have three forms: forced copulation, harassment and intimidation. We studied Australian brush-turkeys, Alectura lathami, to determine whether some male behaviours toward females at incubation mounds could be classified as aggressive, whether males were attempting sexual coercion and, if so, whether the coercion was successful. We found that some male behaviours toward females were significantly more likely to be followed by the cessation of female mound activity, and hence could be classified as aggressive, while others were significantly more likely to be followed by the commencement of female mound activity, and hence could be classified as enticing. Copulation was preceded by higher rates of male enticement and by higher rates of certain types of male aggression. It therefore seemed that males were attempting sexual coercion. There was little evidence, however, that this combination of coercion and enticement was successful in obtaining copulations. While forced copulation did occur, it was infrequent, and no evidence could be found for intimidation. We conclude that harassment is the primary form of sexual coercion by male brush-turkeys. Although sexual coercion is understood to be a sub-optimal tactic, brush-turkey sexual coercion was employed as a primary tactic by dominant males who owned incubation mounds. One possible explanation for this apparent paradox is that aggression is the default solution for social conflicts in this species, and hence can be interpreted as a behavioural syndrome.
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