Electroejaculation and semen buffer evaluation in the microbat Carollia perspicillata

Fasel, Nicolas; Helfenstein, Fabrice; Buff, Samuel; Richner, Heinz

doi:10.1016/j.theriogenology.2014.11.030

Cited by 15 publications

(13 citation statements)

References 36 publications

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“…As found previously (Fasel et al. 2015), a principal component analysis (PCA) on all sperm swimming parameters (excluding the percentage of motile sperm, analyzed separately), identified a first principal component (PC) explaining 53.19% of the variance, which was positively loaded with VCL, VAP, VSL but negatively loaded with BCF, and uncorrelated with the wobble, the number of sperm tracked, and linearity.…”

Section: Methodssupporting

confidence: 66%

Experimental manipulation of reproductive tactics in Seba’s short-tailed bats: consequences on sperm quality and oxidative status

et al. 2019

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To reproduce, males have to fertilize the female’s eggs, sometimes in competition with ejaculates of other males. In species where males display alternative reproductive tactics, whereby territorial males secure mating and non-territorial males have to sneak copulations, the latter might be expected to invest relatively more resources towards sperm quality compared with the territorial males. Sperm cells are especially vulnerable to oxidative stress, which reduces male fertility. Therefore, antioxidant resources are expected to modulate sperm quality, and might be allocated differently between reproductive tactics. To test the link between reproductive tactics, redox profile and sperm quality, we experimentally induced changes in the reproductive tactics of 39 captive males Seba’s short-tailed bats Carollia perspicillata. We monitored the blood and ejaculate oxidative balance, and the sperm quality before, 7 days and 21 days after the manipulation of reproductive tactic. Although ejaculates’ oxidative damage was negatively related to sperm velocity, males exhibited similar blood and ejaculates redox profiles and similar sperm quality, regardless of their reproductive tactic. Possibly, these results arise as a consequence of some constraints having been lifted during the experiment. Our results also suggest that, in Seba’s short-tailed bats, the expression of alternative reproductive tactics is not subjected to strong oxidative constraints. Furthermore, our results could reflect an absence of trade-off between pre- and post-copulatory traits in harem males, as they could be selected to invest both in female attraction and sperm quality, as a consequence of their inability to fully monopolize females.

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Section: Methodssupporting

confidence: 66%

Experimental manipulation of reproductive tactics in Seba’s short-tailed bats: consequences on sperm quality and oxidative status

et al. 2019

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“…Several 2-s videos (median 9, min 1, max 24) of 30 frames/s with a median number of 126.5 sperm track (min 4, max 1133) were then analysed for each session using a CASA plug-in in ImageJ 1.47v (Rasband, National Institute for Health, USA; Wilson-Leedy and Ingermann 2007) to obtain estimates of sperm swimming parameters such as curvilinear velocity (VCL, μm/s) and motility (proportion of moving sperm). The correlation of VCL with other swimming parameters is highly significant in C. perspicillata (Fasel et al 2015). Sperm cells swimming with a higher velocity than non-sperm particles in the sample, i.e.…”

Section: Sperm Mobility Analysismentioning

confidence: 97%

“…Ejaculates were sampled by electro-ejaculation (Fasel et al 2015) on 24 harem 16 peripheral and 19 bachelor males. Males were first anaesthetised using a rodent nosecone nonrebreathing system (Rothacher Medical, CH) of 0.8 l/min oxygen (Carbagas, CH) mixed with 5% of isoflurane (Nicholas Piramal I Ltd, UK) during approximately 5 s, and anaesthesia was maintained with 1 to 2% isoflurane.…”

Section: Ejaculate Collectionmentioning

confidence: 99%

Alternative reproductive tactics, sperm mobility and oxidative stress in Carollia perspicillata (Seba’s short-tailed bat)

Fasel

Wesseling

Fernandez

et al. 2016

Behav Ecol Sociobiol

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In social systems with alternative reproductive tactics, sneakers face a higher level of sperm competition than harem males and hence are predicted to allocate more resources to ejaculates. Antioxidants can protect sperm against oxidative stress, and thus, their allocation to the ejaculate may depend on mating tactic. In this study on the frugivorous bat Carollia perspicillata, we assessed, for harem and sneaker males, four sperm mobility traits, blood and ejaculate markers of the redox balance and the ejaculate to blood ratios of the redox markers. Under higher sperm competition, sneaker males should allocate proportionally more antioxidant resources to the protection of sperm than harem males. In contrast, harem males should favour pre-copulatory functions, which comprise the protection of blood. We found significantly higher sperm velocity and sperm survival in sneakers. There was no correlation between sperm mobility and sperm enzymatic antioxidant activity or ejaculate levels of lipid peroxidation (oxidative damage). Ejaculate levels of lipid peroxidation and sperm survival showed a significantly positive correlation, which could be attributed to the role of reactive oxygen species for sperm capacitation. Harem and sneaker males showed similar levels of redox balance markers in ejaculate and blood. However, harem males showed a higher ratio of oxidized over reduced glutathione in blood, which may indicate higher cellular stress due to higher metabolism. Overall, our findings suggest that sneakers of C. perspicillata compensate for a higher level of sperm competition by higher sperm mobility. Significance statementIn social systems with alternative reproductive tactics, sneakers face higher level of sperm competition than harem males and hence are predicted to allocate more resources to ejaculates. Antioxidants can protect sperm against oxidative stress, and thus, their allocation to the ejaculate may depend on mating tactic. In this study on the frugivorous bat Carollia perspicillata, we found sperm swimming significantly faster and longer in sneaker males compared to harem males. However, traits other than the investigated antioxidant may favour higher sperm mobility. Measured redox pattern in blood of harem males may indicate higher cellular stress due to higher metabolism. Our results provide support to the current sperm competition models at the intraspecific level, which is still debated for internal fertilizers. This study contributes to better understanding the trade-offs and adaptations resulting from alternative reproductive tactics in mammals.

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“…Sperm samples were obtained by electro-stimulation under anesthesia following an established protocol (Fasel et al. 2015; Wesseling et al.…”

Section: Methodsmentioning

confidence: 99%

Penis size and sperm quality, are all bats grey in the dark?

et al. 2018

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Penises play a key role in sperm transport and in stimulating female genitals. This should impact post-copulatory competition, and expose penis characteristics to sexual selective pressures. Studies of male genitalia have repeatedly reported negative static allometries, which mean that, within species, large males have disproportionally small genitals when compared with smaller individuals. Males of some sperm-storing bat species may stand as an exception to such a pattern by arousing from hibernation to copulate with torpid females. The selection for large penises might take place, if a long organ provides advantages during post-copulatory competition and/or if females have evolved mechanisms allowing the choice of sire, relying on characters other than pre-copulatory traits (e.g., penis size). In this study, we measured dimensions of the erected penis in 4 sperm-storing bat species. Furthermore, we collected sperm and evaluated the link between penis dimensions and sperm velocity. Our results revealed steep allometric slopes of the erected penis length in Barbastella barbastellus and an inverse allometry of penis head width in Myotis nattereri. More detailed studies of copulatory behavior are urgently needed to explain the range of observed scaling relations. Furthermore, penis head width correlates with sperm velocity in Plecotus auritus. For this last species, we propose that penis shape might act as a marker of male fertility.

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Electroejaculation and semen buffer evaluation in the microbat Carollia perspicillata

Cited by 15 publications

References 36 publications

Experimental manipulation of reproductive tactics in Seba’s short-tailed bats: consequences on sperm quality and oxidative status

Experimental manipulation of reproductive tactics in Seba’s short-tailed bats: consequences on sperm quality and oxidative status

Alternative reproductive tactics, sperm mobility and oxidative stress in Carollia perspicillata (Seba’s short-tailed bat)

Penis size and sperm quality, are all bats grey in the dark?

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