Status Specific Tailoring of Sperm Behavior in an External Fertilizer

Egeland, Torvald Blikra; Rudolfsen, Geir; Nordeide, Jarle Tryti; Folstad, Ivar

doi:10.3389/fevo.2016.00135

Cited by 9 publications

(18 citation statements)

References 61 publications

(99 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, Arctic charr (Salvelinus alpinus) sperm from dominant males had greater motility in ovarian fluid (Egeland et al 2016). This increased mobility could be cryptic female choice, via ovarian fluid, for dominant male sperm or dominant male sperm could simply be better at moving through ovarian fluid (Egeland et al 2016); however, the experiment could not disentangle the two competing hypotheses. Makiguchi et al (2016b) found that ovarian fluid differentially affects the sperm of precocious parr and anadromous masu salmon (Oncorhynchus masu).…”

Section: Post-spawning Sexual Selectionmentioning

confidence: 99%

Advancing mate choice studies in salmonids

Auld

Noakes

Banks

2019

Rev Fish Biol Fisheries

View full text Add to dashboard Cite

Mate choice in most organisms is not random, but determined by a suite of interacting traits and environmental factors. While the selective pressures underlying differences in mate choice between species, populations, individuals and even within individuals has been gaining interest, there still remains unexplained variation in mate preferences especially in non-model systems. Despite being of social, environmental and economic importance there is comparatively little known about how salmonids and other tetraploids make mate choice decisions in the wild and the resultant reproductive success (i.e. the number of offspring which survive to sexual maturity). Resolving questions related to salmonid mate choice is of particular importance given that humans have been supplementing salmon populations through aquaculture for decades. Despite these efforts, hatchery produced fish have lower reproductive success relative to their wild counterparts and salmon populations are declining. Most studies on mate choice and reproductive success in salmonids focus on body size and major histocompatibility complex based choice. However, mate choice can also be affected by other factors including other genetic factors, predation risk and social environment. Here, we (a) synthesize what is presently known about mate choice and reproductive success in salmonids, (b) identify gaps in knowledge and areas where there is a lack of consensus in results, and (c) suggest interdisciplinary ways of advancing our understanding of mate choice in salmonids and other polyploids.

show abstract

Section: Post-spawning Sexual Selectionmentioning

confidence: 99%

Advancing mate choice studies in salmonids

Auld

Noakes

Banks

2019

Rev Fish Biol Fisheries

View full text Add to dashboard Cite

show abstract

“…Guarding and synchronized spawning by the dominant male may thus leave fewer unfertilized eggs available for the sneaker males, and the eggs will also be more dispersed and difficult to fertilize. Yet, sperm competition occurs when sneaker males try to fertilize a limited number of dispersed, unfertilized eggs (Birkhead & Møller, ; Egeland, Rudolfsen, Nordeide, & Folstad, ; Sørum et al., ).…”

Section: Introductionmentioning

confidence: 99%

Spawning behavior of Arctic charr (Salvelinus alpinus): Spawning synchrony, vibrational communication, and mate guarding

Brattli

Egeland

Nordeide

et al. 2018

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

A mismatch in synchrony between male and female gamete release in external fertilizers can result in reduced or failed fertilization, sperm competition, and reduced paternity. In Arctic charr (Salvelinus alpinus), males can adopt either a guard or sneak tactic resulting in both pre‐ and postcopulatory competition between males with alternative reproduction tactics. Here, spawning behavior of free‐living Arctic charr was video‐recorded, and their reproductive behavior was analyzed. From evaluating 157 spawning events, we observed that females mainly spawned with a guarding male and that the female and the guarding male synchronized timing of gamete release under sperm competition. Although sneakers spawned with higher synchrony than the guarding male in single‐male spawning events, the average sneaker released his milt less synchronized with the female than the guarding male under sperm competition. Approximately 50% of the recorded spawning events occurred under sperm competition, where each event included an average of 2.7 males. Additionally, sneakers were more exposed to sperm competition than guarding males. An influx of males, in close proximity to the female, occurred during the behavioral sequences leading up to egg release, but this influx seemed not dependent on egg release, suggesting that something else than gonadal product attracts sneaker males to the spawning female. Just before and during the actual release of gametes, the spawning couple vibrates their bodies in close contact and it seems likely that this vibrational communication between the spawning couple, which results in a larger amplitude sound wave than seen under regular courting, reveals time of gamete release to sneaker males. Thus, vibrational communication may enable synchrony between the guarding male and the female, and this might be traded against the cost of higher detectability from surrounding sneaker males, eavesdropping in close proximity.

show abstract

“…This is contrary to Egeland et al () who reported relative sperm velocity and motility as the best predictor of male fertilization success in charr from our study population. In the latter study, the two males whose sperm were competing to fertilize eggs in vitro were caged together for four days prior to fertilizations in order to deliberately produce one dominant male with low sperm velocity and one subordinate male with high sperm velocity (see also Egeland et al, ; Rudolfsen et al, ). This “production” of large differences in sperm velocity might explain the contrasting effects of sperm velocity on paternity in the two studies.…”

Section: Discussionmentioning

confidence: 99%

“…In our studied charr population, 76.5% of the ejaculates experience sperm competition and the mean number of males releasing milt in each spawning event is 2.6, suggesting a high level of sperm competition (Sørum et al, ). Sperm velocity and sperm density differ predictably between males adopting dominant or subordinate spawning strategies; that is, subordinates have more sperm with higher velocity in water, yet lower velocity in OF, than dominants (Egeland et al, ; Rudolfsen et al, ). Additionally, velocity of sperm in ejaculates has also been shown to influence fertilization success under sperm competition (Egeland, Rudolfsen, & JT, Folstad I., ; Liljedal et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…That is, OF of individual females specifically promote sperm velocity of certain males over others, suggesting that OF may be a medium in which females exert cryptic female choice (Beirão, Purchase, Wringe, & Fleming, 2015;Dietrich et al, 2008;Nordeide, 2007;Rosengrave et al, 2008;Urbach et al, 2005). Recent studies on external fertilizers have demonstrated that OF may reduce the velocity of sperm from subordinate males relative to that of dominant males (Egeland, Rudolfsen, Nordeide, & Folstad, 2016;Lehnert, Butts, et al, 2017;Makiguchi, Torao, Kojima, & Pitcher, 2016). Thus, subordinates, who invest more resources in their sperm and usually show the highest sperm velocity in water, have lower gains from their investments in sperm velocity than dominant males when sperm enter the OF surrounding eggs.…”

mentioning

confidence: 99%

See 1 more Smart Citation

No support for cryptic choice by ovarian fluid in an external fertilizer

Kleppe

Nordeide

Rudolfsen

et al. 2018

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

Whether the ovarian fluid (OF) represents a selective environment influencing cryptic female choice was tested using an external fertilizer experiencing intense sperm competition and large effects of OF on sperm swimming behavior—the Arctic charr (Salvelinus alpinus). We physically separated the OF from the eggs of reproductively active females and reintroduced either their own OF or fluid from another female to the eggs. The eggs were then fertilized in vitro in a replicated split‐brood design with sperm from two males under synchronized sperm competition trials, while also measuring sperm velocity of the individual males in the individual OFs. We found large effects of males, but no effect of females (i.e., eggs) on paternity, determined from microsatellites. More important, we found no effect of OF treatments on the relative paternity of the two competing males in each pair. This experimental setup does not provide support for the hypothesis that OF plays an important role as medium for cryptic female choice in charr. Power analyses revealed that our sample size is large enough to detect medium‐sized changes in relative paternity (medium‐sized effect sizes), but not large enough to detect small changes in relative paternity. More studies are needed before a conclusion can be drawn about OF's potential influence on paternity under sperm competition—even in charr.

show abstract

Status Specific Tailoring of Sperm Behavior in an External Fertilizer

Cited by 9 publications

References 61 publications

Advancing mate choice studies in salmonids

Advancing mate choice studies in salmonids

Spawning behavior of Arctic charr (Salvelinus alpinus): Spawning synchrony, vibrational communication, and mate guarding

No support for cryptic choice by ovarian fluid in an external fertilizer

Contact Info

Product

Resources

About