Find research datasets worth reusing

publicNov 2025View details →

Data from: Ejaculate investment differs by population, but not wing morph or perceived sperm competition risk, in Pacific field crickets

Open the record for dataset details and reuse information.

publicMar 2020View details →

Egg-induced changes to sperm phenotypes shape patterns of multivariate selection on ejaculates

Open the record for dataset details and reuse information.

publicNov 2024View details →

Data from: Evolution and co-evolution of the suck behaviour, a postcopulatory female resistance trait that manipulates received ejaculate

Open the record for dataset details and reuse information.

publicDec 2021View details →

Condition dependent seminal fluid gene expression and intergenerational paternal effects on ejaculate quality

Open the record for dataset details and reuse information.

opencc-zeroJul 2020View details →

Data from: Female sperm storage mediates postcopulatory costs and benefits of ejaculate anticipatory plasticity in the guppy

Males of many species evolved the capability of adjusting their ejaculate phenotype in response to social cues to match the expected mating conditions. When females store sperm for prolonged time, the expected fitness return of plastic adjustments of ejaculate phenotype may depend on the interval between mating and fertilization. While, prolonged female sperm storage (FSS) increases the opportunity for sperm competition, as a consequence of the longer temporal overlapping of ejaculates from several males, it may also create variable selective forces on ejaculate phenotype, for example by exposing trade-offs between sperm velocity and sperm survival. We evaluated the relationship between the plasticity of ejaculate quality and FSS in the guppy, Poecilia reticulata, a polyandrous livebearing fish in which females store sperm for several months and where stored sperm contribute significantly to a male's lifelong reproductive success. In this species, males respond to the perception of future mating opportunities by increasing the quantity (number) and quality (swimming velocity) of ready-to-use sperm (an anticipatory response called 'sperm priming'). Here we investigated 1) the effect of sperm priming on in-vitro sperm viability at stripping and its temporal decline (as estimate of sperm survival), and, 2) the in-vitro competitive fertilization success in relation to female sperm storage using artificial insemination. As expected, sperm-primed males produced more numerous and faster sperm, but with a reduced in-vitro sperm viability at stripping and after 4 hours, compared to their counterparts. Artificial insemination revealed that the small (non-significant) advantage of primed sperm when fertilization immediately follows insemination, is reversed when eggs are fertilized by female-stored sperm, weeks after insemination. By suggesting a plastic trade-off between sperm velocity and viability, these results demonstrate that prolonged female sperm storage generates divergent selection pressures on ejaculate phenotype.

opencc-zeroSep 2020View details →

Data from: Post-ejaculation thermal stress causes changes to the RNA profile of sperm in an external fertiliser

Sperm cells experience considerable post-ejaculation environmental variation. However, little is known about whether this affects their molecular composition, likely due to the assumption that sperm are transcriptionally quiescent. Nevertheless, recent evidence shows sperm have distinct RNA profiles that affect fertilisation and embryo viability. Moreover, RNAs are expected to be highly sensitive to extracellular changes. One such group of RNAs are heat shock protein (hsp) transcripts, which function in stress responses and are enriched in sperm. Here, we exploit the tractability of the mussel Mytilus galloprovincialis to exposed paired samples of ejaculated sperm to ambient (19 °C) and increased (25 °C) temperatures, then measure (a) sperm motility phenotypes, and (b) mRNA levels of two target genes (hsp70 and hsp90) and several putative reference genes. We find no phenotypic changes in motility, but reduced mRNA levels for hsp90 and the putative reference gene gapdh at 25 °C. This could reflect either decay of specific RNAs, or changes in translation and degradation rates of transcripts to maintain sperm function under stress. These findings represent the first evidence for changes in sperm RNA profiles due to post-ejaculation environments, and suggest that sperm may be more vulnerable to stress from rising temperatures than currently thought.

opencc-zeroOct 2020View details →

Male-male behavioral interactions drive social-dominance mediated differences in ejaculate traits

Higher social status is expected to result in fitness benefits as it secures access to potential mates. In promiscuous species, male reproductive success is also determined by an individual's ability to compete for fertilization after mating by producing high quality ejaculates. However, the complex relationship between a male's investment in social status and ejaculates remains unclear. Here we examine how male social status influences ejaculate quality under a range of social contexts in the pygmy halfbeak Dermogenys cf. collettei, a small, group-living, internally fertilizing freshwater fish. We show that male social status influences ejaculate traits, both in the presence and absence of females. Dominant males produced faster swimming and more viable sperm, two key determinants of ejaculate quality, but only under conditions with frequent male-male behavioral interactions. When male-male interactions were experimentally reduced through the addition of a refuge, differences in ejaculate traits of dominant and subordinate males disappeared. Furthermore, dominant males were in better condition, growing faster and possessing larger livers, highlighting a possible condition-dependence of competitive traits. Contrary to expectations, female presence or absence did not affect sperm swimming speed or testes mass. Together, these results suggest a positive relationship between social status and ejaculate quality in halfbeaks, and highlight that the strength of behavioral interactions between males is a key driver of social-status dependent differences in ejaculate traits.

opencc-zeroDec 2017View details →

Data from: Multivariate sexual selection on ejaculate traits under sperm competition

The widespread prevalence of sperm competition means that ejaculates face intense sexual selection. However, prior investigations of sexual selection on gametes have been hampered by two difficulties: (1) deriving estimates of relative fitness from sperm competition trials that are comparable across rival male and female genotypes; and (2) obtaining measures of competitive fertilization success that are not confounded by post-zygotic effects. Here, we exploit the experimental tractability of a broadcast spawning marine invertebrate to overcome these challenges and characterise multivariate sexual selection on sperm traits when multiple ejaculates compete. In multi-male spawning events, we tracked real-time success of sperm using fluorescent tags that are visible inside fertilized eggs. We then used multivariate selection analyses to identify patterns of linear and non-linear sexual selection on multiple sperm morphology and motility traits. Specifically, we found non-linear selection against divergent combinations of sperm length, velocity and swimming path linearity. These patterns likely reflect the way different swimming strategies allow sperm to locate and track eggs. Our results demonstrate that there are overall patterns of selection on ejaculates across a biologically realistic range of ejaculate-ejaculate and ejaculate-female interactions; therefore, there is the potential for adaptive evolution of ejaculate traits under sperm competition.

opencc-zeroDec 2016View details →

Data from: Haploid selection within a single ejaculate increases offspring fitness

An inescapable consequence of sex in eukaryotes is the evolution of a biphasic life cycle with alternating diploid and haploid phases. The occurrence of selection during the haploid phase can have far-reaching consequences for fundamental evolutionary processes including the rate of adaptation, the extent of inbreeding depression, and the load of deleterious mutations, as well as for applied research into fertilization technology. Although haploid selection is well established in plants, current dogma assumes that in animals, intact fertile sperm within a single ejaculate are equivalent at siring viable offspring. Using the zebrafish Danio rerio, we show that selection on phenotypic variation among intact fertile sperm within an ejaculate affects offspring fitness. Longer-lived sperm sired embryos with increased survival and a reduced number of apoptotic cells, and adult male offspring exhibited higher fitness. The effect on embryo viability was carried over into the second generation without further selection and was equally strong in both sexes. Sperm pools selected by motile phenotypes differed genetically at numerous sites throughout the genome. Our findings clearly link within-ejaculate variation in sperm phenotype to offspring fitness and sperm genotype in a vertebrate and have major implications for adaptive evolution.

opencc-zeroDec 2015View details →

Data from: Intra-ejaculate sperm selection in female zebra finches

Among internal fertilizers, typically fewer than 1% sperm survive the journey through the oviduct. Several studies suggest that the sperm reaching the ovum—the 'fertilizing set'—comprise a non-random sub-population, but the characteristics of this group remain unclear. We tested whether oviductal selection in birds results in a morphologically distinct subset of sperm, by exploiting the fact that the fertilizing set are trapped by the perivitelline layer of the ovum. We show that these sperm have remarkably low morphological variation, as well as smaller head size and greater tail length, compared with those inseminated. Our study shows that the morphological composition of sperm—rather than length alone—influences success in reaching the ovum.

opencc-zeroDec 2016View details →

Data from: Socially cued seminal fluid gene expression mediates responses in ejaculate quality to sperm competition risk

There is considerable evidence that males will increase the number of sperm ejaculated in response to sperm competition risk. However, whether they have the capacity to adjust seminal fluid components of the ejaculate has received less attention. Male crickets (Teleogryllus oceanicus) have been shown to adjust the viability of sperm in their ejaculate in response to sperm competition risk. Here we show that socially mediated plasticity in sperm viability is probably due, at least in part, to male adjustments in the protein composition of the seminal fluid. Seven seminal fluid protein genes were found to have an increased expression in males exposed to rival calls. Increased expression of these genes was correlated with increased sperm viability in whole ejaculates, and gene knockdown confirmed that at least one of these proteins promotes sperm viability. Our results lend support for recent theoretical models that predict complex responses in male allocation to seminal fluid composition in response to sperm competition risk.

opencc-zeroDec 2016View details →

Data from: Sperm competition risk drives rapid ejaculate adjustments mediated by seminal fluid

In many species, males can make rapid adjustments to ejaculate performance in response to sperm competition risk; however, the mechanisms behind these changes are not understood. Here, we manipulate male social status in an externally fertilising fish, chinook salmon (Oncorhynchus tshawytscha), and find that in less than 48 hr, males can upregulate sperm velocity when faced with an increased risk of sperm competition. Using a series of in vitro sperm manipulation and competition experiments, we show that rapid changes in sperm velocity are mediated by seminal fluid and the effect of seminal fluid on sperm velocity directly impacts paternity share and therefore reproductive success. These combined findings, completely consistent with sperm competition theory, provide unequivocal evidence that sperm competition risk drives plastic adjustment of ejaculate quality, that seminal fluid harbours the mechanism for the rapid adjustment of sperm velocity and that fitness benefits accrue to males from such adjustment.

opencc-zeroDec 2020View details →

Data from: Black goby territorial males adjust their ejaculate's characteristics in response to the presence of sneakers

In many species males can rapidly adjust their ejaculate performance in response to changing levels of sperm competition, an ability that is probably mediated by seminal fluid adaptive plasticity. In the black goby, Gobius niger, female spawning in the nest of a territorial male can last hours, and males attach a viscous ejaculate to the nest roof, from which sperm are slowly released. During spawning, sneaker males attempt to approach the nest and release their sperm, and territorial males intensify their defensive effort at the increasing of sneaking pressure. We show here that territorial males adjust the characteristics of their seminal fluid in response to the number of competitor sneakers. Territorial males produce an ejaculate from which sperm are released at a rate that decreases as the number of surrounding competitor sneakers increases. Field observations showed that multiple sneaking attempts occurred sequentially, forcing territorials to frequently leave the nest. Overall these results suggest that the adjustment of seminal fluid viscosity may guarantee a continuous release of sperm from the ejaculate, although at a lower rate, when the territorial male is engaged in prolonged nest defense possibly minimizing the postcopulatory cost of an increased precopulatory mate guarding.

Figure 6 in Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

Figure 6. Number of mates per male and female in seven groups of five pairs of Euxesta eluta flies, observed in the laboratory for a period of 2 hours.

Figure 3 in Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

Figure 3. Per cent of Euxesta eluta copulating pairs, according to days after adult eclosion. Numbers above the diamonds are the sample sizes of pairs (mated and non-mated) according to age category (days after adult eclosion).

Figure 2. Ethogram depicting a in Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

Figure 2. Ethogram depicting a typical mating sequence of Euxesta mazorca. The ethogram was constructed after 1-hour observations of 11 sexually mature pairs. The ethogram was reconstructed based on records of partial and complete records of mating sequences.

Figure 7 in Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

Figure 7. Mating networks of male and female groups of Euxesta eluta observed in the laboratory. Blue squares represent the males and the red circles represent the females. Arrows correspond to an observed copulation. Thicker arrows correspond to remating between pairs. Unconnected nodes represent individuals that did not mate.

Figure 5 in Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

Figure 5. Number of copulations per male and female for seven groups (replicates) of five pairs of Euxesta eluta flies, observed in the laboratory for a period of 2 hours.

Figure 1. Ethogram depicting a in Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

Figure 1. Ethogram depicting a typical mating sequence of Euxesta eluta. The ethogram was constructed after 1-hour observations of 50 sexually mature pairs. The ethogram was reconstructed based on records of partial and complete records of mating sequences.

Figure 4 in Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

Figure 4. Proportion of observed mating and remating pairs of sexually mature Euxesta eluta according to 1-hour intervals over the day.