How to Prepare Spider Sperm for Quantification

Gabel, Eileen; Uhl, Gabriele

doi:10.13156/100.016.0301

Cited by 13 publications

(9 citation statements)

References 4 publications

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“…A). Although no empirical study to our knowledge has explored male allocation in response to sperm use across multiple reproductive events, techniques to count stored sperm have been applied to a range of organisms (e.g., Brillard and Bakst ; Reinhardt and Meister ; Allen et al ; Gabel and Uhl ) and estimates of sperm use u should be relatively easy to obtain. Therefore, in agreement with previous statements (Simmons and Siva‐Jothy ; Simmons ), we argue that sperm utilization inference should not be solely based on patterns of gonadal investment or fertilization success, because they cannot distinguish between alternative mechanisms.…”

Section: Discussionmentioning

confidence: 99%

Female sperm use and storage between fertilization events drive sperm competition and male ejaculate allocation

Requena

Alonzo

2014

Evolution

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Sperm competition theory has traditionally focused on how male allocation responds to female promiscuity, when males compete to fertilize a single clutch of eggs. Here, we develop a model to ask how female sperm use and storage across consecutive reproductive events affect male ejaculate allocation and patterns of mating and paternity. In our model, sperm use (a single parameter under female control) is the main determinant of sperm competition, which alters the effect of female promiscuity on male success and, ultimately, male reproductive allocation. Our theory reproduces the general pattern predicted by existing theory that increased sperm competition favors increased allocation to ejaculates. However, our model predicts a negative correlation between male ejaculate allocation and female promiscuity, challenging the generality of a prevailing expectation of sperm competition theory. Early models assumed that the energetic costs of precopulatory competition and the level of sperm competition are both determined by female promiscuity, which leads to an assumed covariation between these two processes. By modeling precopulatory costs and sperm competition independently, our theoretical framework allows us to examine how male allocation should respond independently to variation in sperm competition and energetic trade-offs in mating systems that have been overlooked in the past. K E Y W O R D S :Male-male competition, male reproductive success, sexual conflict, sexual selection, sperm competition games.

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Section: Discussionmentioning

confidence: 99%

Female sperm use and storage between fertilization events drive sperm competition and male ejaculate allocation

Requena

Alonzo

2014

Evolution

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“…Thus, to improve the homogeneity of the sperm, the samples received ultrasonic treatment in a Misonix XL 2000 sonicator. This was carried out in two sessions of 30 s each at 50% power, with a 30‐second pause in between to avoid overheating of the contents (Gabel & Uhl, ). Prior to counting, the tubes were vortexed on a Vortex‐Genie 2 vortex mixer for 30 s at 70% power.…”

Section: Methodsmentioning

confidence: 99%

One size fits all? Determinants of sperm transfer in a highly dimorphic orb‐web spider

Assis

Foellmer

2016

J of Evolutionary Biology

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The evolutionary significance of widespread hypo-allometric scaling of genital traits in combination with rapid interspecific genital trait divergence has been of key interest to evolutionary biologists for many years and remains poorly understood. Here, we provide a detailed assessment of quantitative genital trait variation in males and females of the sexually highly dimorphic and cannibalistic orb-weaving spider Argiope aurantia. We then test how this trait variation relates to sperm transfer success. In particular, we test specific predictions of the one-size-fits-all and lock-and-key hypotheses for the evolution of genital characters. We use video-taped staged matings in a controlled environment with subsequent morphological microdissections and sperm count analyses. We find little support for the prediction of the one-size-fits-all hypothesis for the evolution of hypo-allometric scaling of genital traits, namely that intermediate trait dimensions confer highest sperm transfer success. Likewise, our findings do not support the prediction of the lock-and-key hypothesis that a tight fit of male and female genital traits mediates highest sperm transfer success. We do, however, detect directional effects of a number of male and female genital characters on sperm transfer, suggesting that genital trait dimensions are commonly under selection in nature. Importantly, even though females are much larger than males, spermatheca size limits the number of sperm transferred, contradicting a previous hypothesis about the evolutionary consequences of genital size dimorphism in extremely size-dimorphic taxa. We also find strong positive effects of male body size and copulation duration on the probability of sperm transfer and the number of sperm transferred, with implications for the evolution of extreme sexual size dimorphism and sexual cannibalism in orb weavers.

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“…For example, for a female of a given size, a slightly larger male may require longer to insert his embolus and transfer sperm than a smaller male. The direct way of determining sperm transfer would have been to examine the females' spermathecae after mating (Bukowski & Christenson, ; Schneider et al ., ; Gabel & Uhl, ), although this is necessarily destructive and our primary aim was the generation of live young. The relationship between insertion duration and sperm transfer in these species warrants further investigation.…”

Section: Discussionmentioning

confidence: 99%

Many a slip: dissecting the causes of reproductive isolation in two species ofTegenariaspiders (Agelenidae)

Oxford

Croucher

2014

Biol J Linn Soc Lond

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Key to our understanding of the mechanisms underlying the process of speciation is the determination of the nature of the barriers to gene flow between related taxa. Species that show zero gene flow in sympatry or parapatry are of little use in this respect. In the present study, we used two closely‐related species of large house spider, Tegenaria saeva and Tegenaria gigantea, which hybridize to a limited extent along a natural contact zone in southern Britain. The species are apparently indistinguishable with respect to habitat utilization and phenology. Laboratory crosses using individuals from both allopatric and parapatric populations suggest that, although male and female courtship, as well as web and cuticular‐borne pheromones, are conserved between the species, mechanical difficulties are experienced during interspecific copulation. Copulation bouts are, on average, significantly shorter during interspecific matings because of these difficulties, and are probably not sufficiently long for effective sperm transfer to take place. In the two cases of successful interspecific crossing, and in subsequent F1 and backcross generations, there are few indications of differential fertility, fecundity or viability, suggesting little post‐zygotic incompatibility. The high success rate of crosses between F1 hybrids and both parental species underlines the principally mechanical barrier to gene flow between these taxa. Once this is breached, there appears to be little impediment to continuing introgression, which could, in some geographical areas at least, ultimately lead to the fusion of the two species. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 355–367.

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How to Prepare Spider Sperm for Quantification

Cited by 13 publications

References 4 publications

Female sperm use and storage between fertilization events drive sperm competition and male ejaculate allocation

Female sperm use and storage between fertilization events drive sperm competition and male ejaculate allocation

One size fits all? Determinants of sperm transfer in a highly dimorphic orb‐web spider

Many a slip: dissecting the causes of reproductive isolation in two species ofTegenariaspiders (Agelenidae)

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