Snail sperm production characteristics vary with sperm competition risk

Oppliger, Anne; Hosken, David J.; Ribi, Georg

doi:10.1098/rspb.1998.0468

Cited by 86 publications

(83 citation statements)

References 47 publications

(68 reference statements)

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“…In addition, although we looked over five copulations, trade-offs may only be detected over a lifetime. A negative association between sperm size and number is a key assumption of sperm competition theory (Pizzari and Parker, 2009), but one for which there is only limited support (for example, see Pitnick, 1996;Oppliger et al, 1998). This is, at least, partly because of the difficulties in assessing the predicted negative association (Pitnick, 1996;Pizzari and Parker, 2009), but in any case, we find no evidence indicative of a trade-off-with the caveats given above, which make the test rather weak.…”

Section: Discussioncontrasting

confidence: 56%

Response to selection and realized heritability of sperm length in the yellow dung fly (Scathophaga stercoraria)

Dobler

Hosken

2009

Heredity

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Sperm length shows considerable phenotypic variation both inter-and intra-specifically, but a general explanation for this variation is lacking. In addition, our understanding of the genetic variation underlying sperm length variation is also limited because there have been few studies on the genetics of sperm size. One factor that could explain the variation in sperm length is that length influences sperm competitiveness, and there is some evidence for this. However, in yellow dung flies (Scathophaga stercoraria), microevolutionary responses to experimental variation at levels of sperm competition indicate that sperm length does not influence sperm competitiveness, although this lack of response may simply indicate sperm length lacks evolutionary potential (that is, it is constrained in some way), in spite of evidence that sperm length is heritable. Here we report on a laboratory study, in which we artificially selected upwards and downwards on sperm length in S. stercoraria. We found that sperm length significantly diverged after four generations of selection, but the response to selection was asymmetrical: upward selection generated a rapid response, but downward did not. We estimated the realized heritability of sperm length to be approximately 50%, which is consistent with previous sire-son estimates. We also assessed the fertility of males from upward and downward lines and found they did not differ. Results are discussed in the context of sperm competition.

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Section: Discussioncontrasting

confidence: 56%

Response to selection and realized heritability of sperm length in the yellow dung fly (Scathophaga stercoraria)

Dobler

Hosken

2009

Heredity

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“…This is carried out to manipulate male perception of the immediate SCI in the subsequent test copulation. Such an experimental design is encountered frequently (Gage & Barnard, 1996;Oppliger et al, 1998;Evans & Magurran, 1999b;Schaus & Sakaluk, 2001;Candolin & Reynolds, 2002;Evans et al, 2003;Pizzarri et al, 2003). However, manipulating male perception of immediate SC in this way possibly also affects male perception of mean SC.…”

Section: Pitfall 1: Testing Mean and Immediate Responsesmentioning

confidence: 99%

“…Oppliger et al, 1998;Evans & Magurran, 1999b;Evans et al, 2003;Reinhardt & Arlt, 2003). With sex ratio manipulation we do not mean the manipulation of immediate SCI by, e.g.…”

Section: Pitfall 4: the Possible Consequences Of Sex Ratio Manipulationmentioning

confidence: 99%

Pitfalls in experiments testing predictions from sperm competition theory

Engqvist

Reinhold

2005

J of Evolutionary Biology

110

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As females of many species mate with more than one male, ejaculates often face competition from the sperm of other males. In recent years, numerous papers have been published on theoretical predictions of evolutionary, behavioural and physiological responses to variation in the strength of sperm competition (SC). These theoretical predictions have also been extensively tested. However, although predictions from SC theory are relatively straightforward, extra caution has to be paid in the design of experiments testing them. One difficulty is for example to disentangle immediate and mean SC risk and intensity. Without carefully designed experiments, it is also very easy to simultaneously increase SC risk and the probability of intense SC – a situation for which we currently have no clear predictions, as the theoretical models to date only assume variation in either SC risk or intensity. In this paper, we discuss these and some other pitfalls related to manipulations of SC risk and intensity and suggest how to avoid them.

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“…It has previously been shown for several species that sperm characteristics, such as sperm density, milt volume or flagellum length, vary according to different mating tactics of males (Leach & Montgomerie, 2000;Neff et al, S P E R M C H A R A C T E R I S T I C S I N P E R C H 2003; Aspbury & Gabor, 2004) or according to the expected sperm competition intensity (Oppliger et al, 1998;Uglem et al, 2002). In Atlantic salmon Salmo salar L., for example, no difference in flagellum length could been found between parr and anadromous males (Vladic et al, 2002), but parr males showed higher sperm density, higher investment in gonads and more motile sperm 10 s after initiation than anadromous males (Vladic & Ja¨rvi, 2001).…”

Section: S P E R M C H a R A C T E R I S T I C S I N P E R C H 1897mentioning

confidence: 99%