Reproductive success of male bank voles (Clethrionomys glareolus): the effect of operational sex ratio and body size

2007 ◽  
Vol 61 (12) ◽  
pp. 1911-1918 ◽  
Author(s):  
Ines Klemme ◽  
Hannu Ylönen ◽  
Jana A. Eccard
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Sex Ratio ◽  
Clethrionomys Glareolus ◽  
Operational Sex Ratio ◽  
Bank Voles

The effects of body size, ownership and sex-ratio on the precopulatory mate guarding of Caprella penantis (Crustacea: Amphipoda)

2009 ◽  
Vol 90 (2) ◽  
pp. 275-279 ◽  
Author(s):  
Fumio Takeshita ◽  
Yasuhisa Henmi
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Laboratory Experiments ◽  
Mate Guarding ◽  
Operational Sex Ratio ◽  
Receptive Female ◽  
Type I ◽  
Male Body ◽  
Precopulatory Mate Guarding ◽  
Secondary Factor

Precopulatory mate guarding behaviour of the skeleton shrimp Caprella penantis is described. Moreover, the effects of body size, ownership and sex-ratio on mate guarding were examined experimentally in the laboratory. In the field population, the operational sex-ratio was male-biased. Guarding pairs, which were collected from the field, continued guarding for an average of 350 minutes in the laboratory, indicating that the normal guarding duration is approximately 10 hours. In this species, two guarding types were found: Type O and Type I-like. In Type O guarding, the male would fold the female into a horseshoe shape, whilst the male held the female parallel to him in Type I-like guarding. In the laboratory experiments, male body size was the most important factor affecting competition for a receptive female; ownership was the secondary factor. Guarding duration was prolonged when the sex-ratio was male-biased. Thus, the precopulatory mate guarding behaviour of C. penantis is influenced by several factors, such as body size, ownership and sex-ratio.

scholarly journals Phenotypic and environmental predictors of reproductive success in painted turtles

2020 ◽  
Author(s):  
Jessica M. Judson ◽  
Luke A. Hoekstra ◽  
Kaitlyn G. Holden ◽  
Fredric J. Janzen
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Mate Choice ◽  
Sex Ratio ◽  
Sex Ratios ◽  
Female Mate Choice ◽  
Painted Turtles ◽  
Weak Evidence ◽  
Adult Sex Ratio ◽  
Siring Success

ABSTRACTSexual selection is often assumed to elicit sexually dimorphic traits. However, most work on this assumption in tetrapod vertebrates has focused on birds. In this field experiment, we assessed relationships between both sexually dimorphic (body size, claw length) and non-dimorphic traits (forelimb stripe color, baseline corticosterone concentrations) and reproductive success in adult painted turtles to explicate the roles of these phenotypes in mate choice and the evolution of sexual dimorphism. We also modified adult sex ratios in experimental ponds to elucidate the role of biased sex ratios on reproductive success, which is a timely test of the potential threat of biased sex ratios on population persistence in a species with temperature-dependent sex determination. We found no strong influence of male phenotypes on male siring success, but female body size and baseline corticosterone concentrations predicted female clutch sizes. We find weak evidence that adult sex ratio influences male siring success, with a male-biased sex ratio producing lower male siring success than a female-biased sex ratio. This study offers evidence that female mate choice may not be an important selective force on male phenotypes, but that instead selection occurs on female phenotypes, particularly body size and corticosterone concentrations. Further, biased adult sex ratios can influence reproductive success of both sexes. Finally, the use of Kompetitive Allele Specific PCR (KASP) was highly successful in parentage analysis, which adds reptiles to the growing list of taxa successfully genotyped with this new technology.Lay SummaryFemale painted turtles aren’t choosy about traits of their mates. In a field experiment, we find that male traits do not predict male fitness, but key female traits (body size and stress levels) do predict female reproductive success. Further, we find weak evidence that adult sex ratio influences individual fitness in this species with environmental sex determination. Ultimately, we reject the long-assumed importance of female mate choice in this freshwater turtle.

Proximate mechanisms responsible for random mating by size in the Himalayan toad Duttaphrynus himalayanus

2020 ◽  
pp. 1-13
Author(s):  
Lixia Zhang ◽  
Yongsun Sheng ◽  
Xiangyu Yuan ◽  
Fei Yu ◽  
Xueting Zhong ◽  
...  
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Female Body ◽  
Random Mating ◽  
Apparent Size ◽  
Operational Sex Ratio ◽  
Female Body Size ◽  
Short Period ◽  
Significant Difference ◽  
Duttaphrynus Himalayanus

Abstract Exploring the mechanisms that affect mating pattern with respect to body size has implications for understanding the evolution of sexual selection. Theory predicts that the absence of a relationship between female body size and fecundity, unbiased operational sex ratio, and a short breeding season will lead to random mating by body size in anuran amphibians. We tested these predictions in the Himalayan toad Duttaphrynus himalayanus inhabiting southeastern Tibet. Our study did not detect any correlation between female body size and number of eggs laid, nor was there a significant difference in the sex ratio of toads captured from the breeding site. In addition, the toads were reproductive for only a short period, from late April to early May (typical of an explosively breeding species). As expected, we detected a weak but not significant relationship between body size of amplexing males and females. Our results revealed no apparent size-assortative pairing in the study population of the Himalayan toad and may contribute to an increasing body of literature on mating patterns in relation to body size in animals with indeterminate growth.

Younger bank voles are more vulnerable to avian predation

2008 ◽  
Vol 86 (9) ◽  
pp. 1074-1078 ◽  
Author(s):  
Taru Meri ◽  
Matti Halonen ◽  
Tapio Mappes ◽  
Jukka Suhonen
Keyword(s):  
Sex Ratio ◽  
Clethrionomys Glareolus ◽  
Selective Predation ◽  
Field Sample ◽  
Avian Predator ◽  
Avian Predation ◽  
Bank Voles ◽  
Significant Difference ◽  
Total Impact ◽  
Selection Of

The importance of predation on prey populations is mainly determined by the number of eaten prey. However, the total impact of predation might also be determined by the selection of certain prey individuals, e.g., different sexes or age categories. Here we tested selective predation by an avian predator, the pygmy owl ( Glaucidium passerinum (L., 1758)), on bank voles ( Myodes ( Clethrionomys ) glareolus (Schreber, 1780)). We compared the sex, age, and mass of hoarded prey with the animals snap-trapped from the field. There were no differences in the sex ratio between hoarded bank voles and those available in the field. However, hoarded voles were significantly younger than ones in the field sample. There was no statistically significant difference in mass between animals from larders and from the field. We suggest that the greater vulnerability of younger animals to predation might be due to their higher activity, or alternatively, they might be forced to forage in less safe habitats.

Unexpected offspring sex ratios in response to habitat quality in a size-dimorphic bark beetle

1999 ◽  
Vol 77 (4) ◽  
pp. 524-529 ◽  
Author(s):  
Risa D Sargent ◽  
Mary L Reid
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Sex Ratio ◽  
Habitat Quality ◽  
Bark Beetle ◽  
Sex Ratios ◽  
Diploid Species ◽  
Differential Mortality ◽  
Male Reproductive Success ◽  
Offspring Sex

Facultative sex ratio manipulation has been examined in a limited number of diploid species, mainly vertebrates. We tested the prediction that mothers would preferentially place males in conditions conducive to large size in the diploid pine engraver bark beetle, Ips pini. In this species, males are the larger sex and therefore male reproductive success was expected to be more dependent on body size than female reproductive success. Because body size is largely environmentally determined in bark beetles, mothers were expected to alter sex ratios in response to habitat quality. Contrary to predictions, offspring sex ratios tended to be more female biased in situations conducive to large offspring size than in situations producing offspring of small size. We were able to rule out nonadaptive explanations such as differential mortality or development times of males and females, suggesting that the observed pattern is adaptive. This study provides a rare example of sex ratio manipulation in diploid insects. However, the unexpected direction of sex ratio biases suggests that daughters gain a yet unknown benefit from being reared in high-quality conditions that surpasses the fitness that would be gained from producing relatively larger sons.

scholarly journals Effects of litter size on pup defence and weaning success of neighbouring bank vole females

2002 ◽  
Vol 80 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Pernilla Jonsson ◽  
Jep Agrell ◽  
Esa Koskela ◽  
Tapio Mappes
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Litter Size ◽  
Bank Vole ◽  
Dominance Rank ◽  
The Other ◽  
Clethrionomys Glareolus ◽  
Bank Voles ◽  
Litter Size Manipulation

Reproductive success of territorial female mammals depends partly on their capability to defend their young from conspecific intruders. However, how this is related to the characteristics of females and their litter sizes is largely unknown. The defence activity of 25 female bank voles (Clethrionomys glareolus) in relation to the number of offspring was studied in a behavioural arena by manipulating litter sizes (–2 pups or +2 pups). Infanticidal male bank voles were used as intruders–predators. Moreover, the weaning success (weaned at least one offspring or none) of 15 pairs of neighbouring females was investigated in a large indoor runway system. In each pair of females, the litter size of one female was reduced (–2 pups) and the litter size of the other enlarged (+2 pups). Defence activity of females increased with the number of offspring and the mother's size. However, weaning success of neighbours was related only to their body mass, and litter-size manipulation did not affect weaning success. Present results indicate that, although bank vole females increase their defence intensity with an increase in the number of pups, the weaning success of neighbouring females may be primarily determined by their size and dominance rank.

scholarly journals Quantitative measure of sexual selection with respect to the operational sex ratio: a comparison of selection indices

2006 ◽  
Vol 274 (1606) ◽  
pp. 143-150 ◽  
Author(s):  
Suzanne C Mills ◽  
Alessandro Grapputo ◽  
Esa Koskela ◽  
Tapio Mappes
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Selection Index ◽  
Natural Populations ◽  
Quantitative Measure ◽  
Clethrionomys Glareolus ◽  
Operational Sex Ratio ◽  
Plasma Testosterone ◽  
Bank Voles ◽  
Selection Indices

Despite numerous indices proposed to predict the evolution of mating systems, a unified measure of sexual selection has remained elusive. Three previous studies have compared indices of sexual selection under laboratory conditions. Here, we use a genetic study to compare the most widely used measures of sexual selection in natural populations. We explored the mating and reproductive successes of male and female bank voles, Clethrionomys glareolus , across manipulated operational sex ratios (OSRs) by genotyping all adult and pup bank voles on 13 islands using six microsatellite loci. We used Bateman's principles ( I s and I and Bateman gradients) and selection coefficients ( s ′ and β ′) to evaluate, for the first time, the genetic mating system of bank voles and compared these measures with alternative indices of sexual selection (index of monopolization and Morisita's index) across the OSRs. We found that all the sexual selection indices show significant positive intercorrelations for both males and females, suggesting that Bateman's principles are an accurate and a valid measure of the mating system. The Bateman gradient, in particular, provides information over and above that of other sexual selection indices. Male bank voles show a greater potential for sexual selection than females, and Bateman gradients indicate a polygynandrous mating system. Selection coefficients reveal strong selection gradients on male bank vole plasma testosterone level rather than body size.

scholarly journals Long-term fitness benefits of polyandry in a small mammal, the bank vole Clethrionomys glareolus

2008 ◽  
Vol 275 (1638) ◽  
pp. 1095-1100 ◽  
Author(s):  
Ines Klemme ◽  
Hannu Ylönen ◽  
Jana Anja Eccard
Keyword(s):  
Body Size ◽  
Small Mammal ◽  
Bank Vole ◽  
Clethrionomys Glareolus ◽  
Adaptive Function ◽  
Single Male ◽  
Bank Voles ◽  
Fitness Traits ◽  
Fitness Benefits

Polyandry, i.e. mating with multiple males within one reproductive event, is a common female mating strategy but its adaptive function is often unclear. We tested whether polyandrous females gain genetic benefits by comparing fitness traits of monandrous (mated twice with a single male) and polyandrous (mated twice with two different males) female bank voles Clethrionomys glareolus . We raised the offspring in the laboratory until adulthood and measured their body size, before releasing them to outdoor enclosures to overwinter. At the onset of the breeding season in the following spring, we found that offspring of polyandrous females performed significantly better at reproduction than those of monandrous females. This was mainly due to sons of polyandrous females producing significantly more offspring than those of monandrous females. No significant differences were found for offspring body mass or winter survival between the two treatments. Our results appear to provide evidence that bank vole females gain long-term benefits from polyandry.

Some data on the fertility of bank voles (Clethrionomys glareolus britannicus) in the laboratory supporting the hypothesis of induced ovulation

1984 ◽  
Vol 18 (1) ◽  
pp. 33-35 ◽  
Author(s):  
F. O. Ödberg
Keyword(s):  
Sex Ratio ◽  
Clethrionomys Glareolus ◽  
Induced Ovulation ◽  
Bank Voles

83 (40%) litters with an average of 3·42 pups and unbiased sex ratio were born of 207 couples. Fertility and litter average were higher in summer and autumn. Most females were fertilized on the 1st day spent with a male, which supports the mating-induced ovulation hypothesis. Infantile mortality was highest at birth and during the 1st 5 days of life. 26% of the pups died before weaning (day 25), i.e. an average of 1 per litter.

Higher Reproductive Success among Kin Groups of Bank Voles (Clethrionomys Glareolus)

Ecology ◽  
1995 ◽  
Vol 76 (4) ◽  
pp. 1276-1282 ◽  
Author(s):  
Tapio Mappes ◽  
Hannu Ylonen ◽  
Jussi Viitala
Keyword(s):  
Reproductive Success ◽  
Clethrionomys Glareolus ◽  
Bank Voles
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