scholarly journals Copulation with immature females increases male fitness in cannibalistic widow spiders

2016 ◽  
Vol 12 (9) ◽  
pp. 20160516 ◽  
Author(s):  
M. Daniela Biaggio ◽  
Iara Sandomirsky ◽  
Yael Lubin ◽  
Ally R. Harari ◽  
Maydianne C. B. Andrade
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Sperm Storage ◽  
Reproductive Value ◽  
Male Fitness ◽  
Mating Tactic ◽  
Final Moult ◽  
Storage Organs

Copulatory cannibalism of male ‘widow’ spiders (genus Latrodectus ) is a model example of the extreme effects of sexual selection, particularly in L. hasselti and L. geometricus where males typically facilitate cannibalism by females and mate only once. We show that these males can increase their reproductive success by copulating with final-instar, immature females after piercing the female's exoskeleton to access her newly developed sperm storage organs. Females retain sperm through their final moult and have similar fecundity to adult-mated females. This is an adaptive male tactic because immature mating increases insemination success relative to adult mating (which predicts higher paternity) and moreover, rarely ends in cannibalism, so males can mate again. Although successful only during a brief period before the female's final moult, males may employ this tactic when they associate with final-instar females in nature. Consistent with this, one-third of L. hasselti females collected as immatures in nature were already mated. Immature mating alters sexual selection on these otherwise monogynous males, and may explain male traits allowing facultative polygyny in Latrodectus . Since male cohabitation with immature females is common among invertebrates, immature mating may be a widespread, previously unrecognized mating tactic, particularly when unmated females are of high reproductive value.

scholarly journals Do metrics of sexual selection conform to Bateman's principles in a wind-pollinated plant?

2019 ◽  
Vol 286 (1905) ◽  
pp. 20190532 ◽  
Author(s):  
Jeanne Tonnabel ◽  
Patrice David ◽  
John R. Pannell
Keyword(s):  
Spatial Distribution ◽  
Sexual Selection ◽  
Reproductive Success ◽  
Pollen Dispersal ◽  
Male Fitness ◽  
Female Fitness ◽  
Dioecious Plant ◽  
Common Gardens ◽  
Mate Acquisition ◽  
Mercurialis Annua

Bateman's principles posit that male fitness varies more, and relies more on mate acquisition, than female fitness. While Bateman's principles should apply to any organism producing gametes of variable sizes, their application to plants is potentially complicated by the high levels of polyandry suspected for plants, and by variation in the spatial distribution of prospective mates. Here we quantify the intensity of sexual selection by classical Bateman metrics using two common gardens of the wind-pollinated dioecious plant Mercurialis annua . Consistent with Bateman's principles, males displayed significantly positive Bateman gradients (a regression of fitness on mate number), whereas the reproductive success of females was independent of their ability to access mates. A large part of male fitness was explained by their mate number, which in turn was associated with males' abilities to disperse pollen. Our results suggest that sexual selection can act in plant species in much the same way as in many animals, increasing the number of mates through traits that promote pollen dispersal.

scholarly journals Acp36DE is required for uterine conformational changes in mated Drosophila females

2009 ◽  
Vol 106 (37) ◽  
pp. 15796-15800 ◽  
Author(s):  
Frank W. Avila ◽  
Mariana F. Wolfner
Keyword(s):  
Reproductive Success ◽  
Sperm Competition ◽  
Conformational Changes ◽  
Reproductive Tract ◽  
Sperm Storage ◽  
Internal Fertilization ◽  
Content Type ◽  
Storage Organs ◽  
Subsequent Storage ◽  
And Behavior

In a multitude of animals with internal fertilization, including insects and mammals, sperm are stored within a female's reproductive tract after mating. Defects in the process of sperm storage drastically reduce reproductive success. In Drosophila males, “Acp” seminal proteins alter female postmating physiology and behavior, and are necessary for several aspects of sperm storage. For example, Acps cause a series of conformational changes in the mated female's reproductive tract that occur during and immediately after mating. These conformational changes have been hypothesized to aid both in the movement of sperm within the female and in the subsequent storage of those sperm. We used RNAi to systematically knock down several Acps involved in sperm storage to determine whether they played a role in the mating-induced uterine conformational changes. Mates of males lacking the glycoprotein Acp36DE, which is needed for the accumulation of sperm in the storage organs, fail to complete the full sequence of the conformational changes. Our results show that uterine conformational changes are important for proper accumulation of sperm in storage and identify a seminal protein that mediates these changes. Four Acps included in this study, previously shown to affect sperm release from storage (CG9997, CG1656, CG1652, and CG17575), are not necessary for uterine conformational changes to occur. Rather, consistent with their role in later steps of sperm storage, we show here that their presence can affect the outcome of sperm competition situations.

scholarly journals Exceptional long-term sperm storage by a female vertebrate

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252049
Author(s):  
Brenna A. Levine ◽  
Gordon W. Schuett ◽  
Warren Booth
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Genetic Analysis ◽  
Mating Systems ◽  
Sperm Storage ◽  
Male Reproductive Success ◽  
Vertebrate Species ◽  
Paternal Contribution ◽  
Facultative Parthenogenesis

Females of many vertebrate species have the capacity to store sperm within their reproductive tracts for prolonged periods of time. Termed long-term sperm storage, this phenomenon has many important physiological, ecological, and evolutionary implications, particularly to the study of mating systems, including male reproductive success and post-copulatory sexual selection. Reptiles appear particularly predisposed to long-term sperm storage, with records in most major lineages, with a strong emphasis on turtles and squamates (lizards, snakes, but not the amphisbaenians). Because facultative parthenogenesis is a competing hypothesis to explain the production of offspring after prolonged separation from males, the identification of paternal alleles through genetic analysis is essential. However, few studies in snakes have undertaken this. Here, we report on a wild-collected female Western Diamond-backed Rattlesnake, Crotalus atrox, maintained in isolation from the time of capture in September 1999, that produced two healthy litters approximately one and six years post capture. Genetic analysis of the 2005 litter, identified paternal contribution in all offspring, thus rejecting facultative parthenogenesis. We conclude that the duration of long-term sperm storage was approximately 6 years (71 months), making this the longest period over which a female vertebrate has been shown to store sperm that resulted in the production of healthy offspring.

scholarly journals Expression of Mst89B and CG31287 is Needed for Effective Sperm Storage and Egg Fertilization in Drosophila

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 289
Author(s):  
Gurman Grewal ◽  
Bahar Patlar ◽  
Alberto Civetta
Keyword(s):  
Germ Line ◽  
Sperm Storage ◽  
Mature Sperm ◽  
Sperm Production ◽  
Cytogenetic Map ◽  
Egg Hatchability ◽  
Storage Organs ◽  
Competitive Success ◽  
Paternity Success ◽  
And Storage

In Drosophila, male reproductive fitness can be affected by any number of processes, ranging from development of gametes, transfer to and storage of mature sperm within the female sperm storage organs, and utilization of sperm for fertilization. We have previously identified the 89B cytogenetic map position of D. melanogaster as a hub for genes that effect male paternity success when disturbed. Here, we used RNA interference to test 11 genes that are highly expressed in the testes and located within the 89B region for their role in sperm competition and male fecundity when their expression is perturbed. Testes-specific knockdown (KD) of bor and CSN5 resulted in complete sterility, whereas KD of CG31287, Manf and Mst89B, showed a breakdown in sperm competitive success when second to mate (P2 < 0.5) and reduced fecundity in single matings. The low fecundity of Manf KD is explained by a significant reduction in the amount of mature sperm produced. KD of Mst89B and CG31287 does not affect sperm production, sperm transfer into the female bursa or storage within 30 min after mating. Instead, a significant reduction of sperm in female storage is observed 24 h after mating. Egg hatchability 24 h after mating is also drastically reduced for females mated to Mst89B or CG31287 KD males, and this reduction parallels the decrease in fecundity. We show that normal germ-line expression of Mst89B and CG31287 is needed for effective sperm usage and egg fertilization.

scholarly journals Functional morphology of immature mating in a widow spider

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Lenka Sentenská ◽  
Aileen Neumann ◽  
Yael Lubin ◽  
Gabriele Uhl
Keyword(s):  
Sperm Competition ◽  
Storage Conditions ◽  
Sperm Storage ◽  
Sperm Transfer ◽  
Costs And Benefits ◽  
Micro Computed Tomography ◽  
Mating Tactics ◽  
Adult Females ◽  
Storage Organs ◽  
Widow Spider

Abstract Background Mating generally occurs after individuals reach adulthood. In many arthropods including spiders, the adult stage is marked by a final moult after which the genitalia are fully developed and functional. In several widow spider species (genus Latrodectus), however, immature females may mate a few days before they moult to adulthood, i.e. in their late-subadult stage. While the “adult” mating typically results in cannibalism, males survive the “immature” mating. During both “immature” and “adult” matings, males leave parts of their paired copulatory organs within female genitalia, which may act as mating plugs. To study potential costs and benefits of the two mating tactics, we investigated female genital morphology of the brown widow spider, L. geometricus. Light microscopy, histology and micro-computed tomography of early-subadult, late-subadult and adult females were conducted to determine the overall pattern of genital maturation. We compared genitalia of mated late-subadult and adult females to reveal potential differences in the genitalic details that might indicate differential success in sperm transfer and different environments for sperm storage and sperm competition. Results We found that the paired sperm storage organs (spermathecae) and copulatory ducts are developed already in late-subadult females and host sperm after immature mating. However, the thickness of the spermathecal cuticle and the staining of the secretions inside differ significantly between the late-subadult and adult females. In late-subadult females mating plugs were found with higher probability in both spermathecae compared to adult females. Conclusions Sperm transfer in matings with late-subadult females follows the same route as in matings with adult females. The observed differences in the secretions inside the spermathecae of adult and late-subadult females likely reflect different storage conditions for the transferred sperm which may lead to a disadvantage under sperm competition if the subadult female later re-mates with another male. However, since males mating with late-subadult females typically transfer sperm to both spermathecae they might benefit from numerical sperm competition as well as from monopolizing access to the female sperm storage organs. The assessment of re-mating probability and relative paternity will clarify the costs and benefits of the two mating tactics in light of these findings.

More sires may enhance offspring fitness in Northern Map Turtles (Graptemys geographica)

2013 ◽  
Vol 91 (8) ◽  
pp. 581-588 ◽  
Author(s):  
Nicola Banger ◽  
Gabriel Blouin-Demers ◽  
Grégory Bulté ◽  
Stephen C. Lougheed
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Hatching Success ◽  
Locomotor Performance ◽  
Conservative Estimate ◽  
Genetic Quality ◽  
Offspring Fitness ◽  
Sexual Selection Theory ◽  
Map Turtles ◽  
Graptemys Geographica

Sexual selection theory predicts that males should be promiscuous to maximize their reproductive success, while females should be choosy. Yet females of many taxa often produce progeny sired by multiple males, indicating that promiscuity can be important for the reproductive success of females. Promiscuity may enhance the fitness of females if it increases the genetic quality, or the genetic variety, and thus the viability of their offspring. We quantified the number of sires per clutch in a population of Northern Map Turtles (Graptemys geographica (LeSueur, 1817)) in Lake Opinicon, Ontario, Canada, and tested whether the number of sires affects several metrics of viability in hatchlings. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males, but there was no evidence that larger clutches are sired by more males. Clutches sired by more males had higher hatching success and survival, but the differences were not statistically significant. We did not find any effect of the number of sires on hatchling morphology or locomotor performance. Collectively, our results partially support the hypothesis that promiscuity can increase the reproductive success of female Northern Map Turtles.

Size does not matter for male Marbled Salamanders (Ambystoma opacum)

2015 ◽  
Vol 93 (10) ◽  
pp. 735-740
Author(s):  
D.A. Croshaw ◽  
J.H.K. Pechmann
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Reproductive Success ◽  
Large Male ◽  
Male Mating ◽  
Ambystoma Opacum ◽  
Positive Assortative Mating ◽  
Important Trait ◽  
Breeding Groups ◽  
Gravid Females

Understanding the phenotypic attributes that contribute to variance in mating and reproductive success is crucial in the study of evolution by sexual selection. In many animals, body size is an important trait because larger individuals enjoy greater fitness due to the ability to secure more mates and produce more offspring. Among males, this outcome is largely mediated by greater success in competition with rival males and (or) advantages in attractiveness to females. Here we tested the hypothesis that large male Marbled Salamanders (Ambystoma opacum (Gravenhorst, 1807)) mate with more females and produce more offspring than small males. In experimental breeding groups, we included males chosen specifically to represent a range of sizes. After gravid females mated and nested freely, we collected egg clutches and genotyped all adults and samples of hatchlings with highly variable microsatellite markers to assign paternity. Size had little effect on male mating and reproductive success. Breeding males were not bigger than nonbreeding males, mates of polyandrous females were not smaller than those of monogamous females, and there was no evidence for positive assortative mating by size. Although body size did not matter for male Marbled Salamanders, we documented considerable fitness variation and discuss alternative traits that could be undergoing sexual selection.

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