Sexual Selection in Dung Beetles .2. Female Fecundity as an Estimate of Male Reproductive Success in Relation to Horn Size, and Alternative Behavioral Strategies in Onthophagus-Binodis Thunberg (Scarabaeidae, Onthophagini)

1988 ◽  
Vol 36 (5) ◽  
pp. 521 ◽  
Author(s):  
D Cook
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Mate Guarding ◽  
Mating Strategies ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Behavioral Strategies ◽  
Alternative Tactics ◽  
Female Fecundity ◽  
Similar Body

One component of the reproductive success (fitness) of Onthophagus binodis Thunberg males was estimated by the number of offspring their mate produced relative to male horn and body size. O. binodis males consist of large horned and small hornless morphs. Female fecundity was significantly increased when reproducing with: (1) large horned males compared with small hornless males; (2) the horned morph compared with the hornless morph of males with similar body size. Horned males cooperating with females invest a considerable effort in providing each egg with dung. Hornless males do not appear to assist females after mating. Alternative male mating strategies are predicted under intense intrasexual competition. As hornless O. binodis males persist in large numbers alongside cooperative, mate guarding horned males, selection should favour alternative tactics by hornless males to gain reproductive opportunities.

scholarly journals A Comparative Study of Mating Strategies in Two Species of Philanthus (Hymenoptera: Sphecidae)

1980 ◽  
Vol 4 ◽  
pp. 48-52
Author(s):  
Howard Evans ◽  
Kevin O'Neill
Keyword(s):  
Reproductive Success ◽  
Activity Patterns ◽  
Important Variable ◽  
Mating Strategies ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Male Mating Strategies ◽  
Jackson Hole ◽  
Male Activity

Our work on the reproductive biology of Philanthus pulcher and P. zebratus in Jackson Hole in 1980 was a continuation of a study which had three major objectives. The first was to determine the relationship between female and male activity patterns. As in other species with extensive female-contributed and no male-contributed parental investment, females are a resource necessary for reproductive success of males. Thus, the activity of females in time and space should be an important parameter affecting the evolution of male mating strategies. Our work in this area is being combined with data we have gathered elsewhere on other species of Philanthus (O'Neill and Evans, unpublished). The second objective was to determine what characteristic of males was important in determining reproductive success and the form of the mating strategy. Since our preliminary data on Philanthus indicated that body size may be the most important variable affecting male reproductive success, we concentrated on this aspect of male biology. This report will focus on our results in this area. The third objective was to determine the role of male-produced sex pheromones in the mating system. (* Erratum: pp. 56 and 57 should be 51 and 52 )

scholarly journals Effects of body size on male mating tactics and paternity in black bears, Ursus americanus

2003 ◽  
Vol 81 (7) ◽  
pp. 1257-1268 ◽  
Author(s):  
Adrienne I Kovach ◽  
Roger A Powell
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Dna Analysis ◽  
Ursus Americanus ◽  
Mating Behaviour ◽  
Black Bear ◽  
Lifetime Reproductive Success ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Mating Tactics

The reproductive behaviour of large, solitary mammals is difficult to study. Owing to their secretive nature and wide-ranging habits, aspects of male mating behaviour are poorly documented in solitary than in social species. We used radiotelemetry and microsatellite DNA analysis to investigate the influence of body size on male mating tactics and short-term reproductive success in the black bear, Ursus americanus, a solitary carnivore. We investigated male ranging behaviour and documented male encounters with breeding females to determine whether males employed conditional mating tactics according to their body sizes. We found that male home-range sizes were not positively associated with body size, but encounter rates with breeding females were. Although all males searched widely for females, mating access appeared to be largely determined by fighting ability. Large males encountered more breeding females and had more frequent encounters during the females' estimated receptive periods than did small- and medium-sized males. Paternity was highly skewed toward the three dominant males who fathered 91% of the cubs sampled during the 3-year study. Paternity was correlated with the frequency of male encounters during female receptive periods. Male encounters, however, overestimated the success of medium-sized males and underestimated the overall variance in male reproductive success. Multiple paternity occurred in two of seven litters, indicating that sperm competition is important in black bear mating behaviour. Implications for male lifetime reproductive success are discussed.

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.

scholarly journals The measure and significance of Bateman's principles

2014 ◽  
Vol 281 (1782) ◽  
pp. 20132973 ◽  
Author(s):  
Julie M. Collet ◽  
Rebecca F. Dean ◽  
Kirsty Worley ◽  
David S. Richardson ◽  
Tommaso Pizzari
Keyword(s):  
Reproductive Success ◽  
Mating Success ◽  
Male Reproductive Success ◽  
Female Fecundity ◽  
Male Preference ◽  
Bateman Gradient ◽  
Red Junglefowl ◽  
Experimental Approaches ◽  
Empirical Tests ◽  
Paternity Share

Bateman's principles explain sex roles and sexual dimorphism through sex-specific variance in mating success, reproductive success and their relationships within sexes (Bateman gradients). Empirical tests of these principles, however, have come under intense scrutiny. Here, we experimentally show that in replicate groups of red junglefowl, Gallus gallus , mating and reproductive successes were more variable in males than in females, resulting in a steeper male Bateman gradient, consistent with Bateman's principles. However, we use novel quantitative techniques to reveal that current methods typically overestimate Bateman's principles because they (i) infer mating success indirectly from offspring parentage, and thus miss matings that fail to result in fertilization, and (ii) measure Bateman gradients through the univariate regression of reproductive over mating success, without considering the substantial influence of other components of male reproductive success, namely female fecundity and paternity share. We also find a significant female Bateman gradient but show that this likely emerges as spurious consequences of male preference for fecund females, emphasizing the need for experimental approaches to establish the causal relationship between reproductive and mating success. While providing qualitative support for Bateman's principles, our study demonstrates how current approaches can generate a misleading view of sex differences and roles.

scholarly journals MALE MATING SUCCESS AND FEMALE PREFERENCE FOR MULTIPLE TRAITS IN THE TWOLINE PUPFISH (CYPRINODON BIFASCIATUS)

Behaviour ◽  
2001 ◽  
Vol 138 (10) ◽  
pp. 1303-1318 ◽  
Author(s):  
Murray Itzkowitz ◽  
Anna Ludlow ◽  
David Baird
Keyword(s):  
Body Size ◽  
Laboratory Experiments ◽  
Female Preference ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Male Body ◽  
Male Mating Success ◽  
Substrate Type ◽  
Sandy Substrate ◽  
Cyprinodon Bifasciatus

AbstractSummary Using the twoline pupfish (Cyprinodon bifasciatus), a species with a resource-based polygynous breeding system, we examined male mating success in the wild, and we experimentally investigated effects of male body size and substrate type on female association patterns in the laboratory. Our purpose was to (a) identify the traits contributing to male reproductive success in the field, (b) measure preferences for each trait independently in the laboratory, and (c) determine the relative importance of each trait. Field observations revealed that substrate type was the main determinant of male reproductive success: males defending territories on rocks mated significantly more often than males defending territories on silt or sand. Laboratory experiments supported the field data, and revealed that the female preference for substrate type was independent of male body size effects. When given a choice between two males matched for size but differing in the type of substrates they were defending, females preferred the male on the rocky substrate over the male on the sandy substrate. Laboratory experiments also revealed a female preference for larger males when substrate type was held constant. Finally, when females were presented with a choice between a large male on a sandy substrate and a small male on a rocky substrate, no clear preference emerged. We provide several interpretations for this result, and we argue that both traits may be strong predictors of the male's competitive ability.

scholarly journals Allee effect in polar bears: a potential consequence of polychlorinated biphenyl contamination

2016 ◽  
Vol 283 (1843) ◽  
pp. 20161883 ◽  
Author(s):  
Viola Pavlova ◽  
Jacob Nabe-Nielsen ◽  
Rune Dietz ◽  
Christian Sonne ◽  
Volker Grimm
Keyword(s):  
Reproductive Success ◽  
Population Growth ◽  
Polar Bear ◽  
Allee Effect ◽  
Polychlorinated Biphenyl ◽  
Sperm Quality ◽  
Male Competition ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Polar Bears

Polar bears ( Ursus maritimus ) from East Greenland and Svalbard exhibited very high concentrations of polychlorinated biphenyls (PCBs) in the 1980s and 1990s. In Svalbard, slow population growth during that period was suspected to be linked to PCB contamination. In this case study, we explored how PCBs could have impacted polar bear population growth and/or male reproductive success in Svalbard during the mid-1990s by reducing the fertility of contaminated males. A dose–response relationship linking the effects of PCBs to male polar bear fertility was extrapolated from studies of the effects of PCBs on sperm quality in rodents. Based on this relationship, an individual-based model of bear interactions during the breeding season predicted fertilization success under alternative assumptions regarding male–male competition for females. Contamination reduced pregnancy rates by decreasing the availability of fertile males, thus triggering a mate-finding Allee effect, particularly when male–male competition for females was limited or when infertile males were able to compete with fertile males for females. Comparisons of our model predictions on age-dependent reproductive success of males with published empirical observations revealed that the low representation of 10–14-year-old males among breeding males documented in Svalbard in mid-1990s could have resulted from PCB contamination. We conclude that contamination-related male infertility may lead to a reduction in population growth via an Allee effect. The magnitude of the effect is largely dependent on the population-specific mating system. In eco-toxicological risk assessments, appropriate consideration should therefore be given to negative effects of contaminants on male fertility and male mating behaviour.

Interplay of male traits, male mating strategies and female mate choice in the Asian elephant, Elephas maximus

Behaviour ◽  
2015 ◽  
Vol 152 (7-8) ◽  
pp. 1113-1144 ◽  
Author(s):  
Karpagam Chelliah ◽  
Raman Sukumar
Keyword(s):  
Mate Choice ◽  
Mate Guarding ◽  
Female Mate Choice ◽  
Mating Strategies ◽  
Asian Elephant ◽  
Dominant Male ◽  
Male Mating ◽  
Male Body ◽  
Female Mate ◽  
Male Mating Strategies

Elaborate male traits with no apparent adaptive value may have evolved through female mate discrimination. Tusks are an elaborate male-only trait in the Asian elephant that could potentially influence female mate choice. We examined the effect of male body size, tusk possession and musth status on female mate choice in an Asian elephant population. Large/musth males received positive responses from oestrous females towards courtship significantly more often than did small/non-musth males. Young, tusked non-musth males attempted courtship significantly more often than their tuskless peers, and received more positive responses (though statistically insignificant) than did tuskless males. A positive response did not necessarily translate into mating because of mate-guarding by a dominant male. Female elephants appear to choose mates based primarily on traits such as musth that signal direct fertility benefits through increased sperm received than for traits such as tusks that may signal only indirect fitness benefits.

The Relationships Among Population Density, Individual Size, Mating Tactics, and Reproductive Success in a Hermaphroditic Fish, Serranus Fasciatus

Behaviour ◽  
1990 ◽  
Vol 113 (1-2) ◽  
pp. 57-80 ◽  
Author(s):  
Christopher W. Petersen
Keyword(s):  
Reproductive Success ◽  
Social Group ◽  
Local Density ◽  
Social Systems ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Mating Tactics ◽  
Intermediate Group ◽  
Female Function ◽  
Mating Opportunities

AbstractThe hermaphroditic reef fish Serranus fasciatus exhibits three types of social systems. The size of a social group is correlated with the local density of conspecifics. At very low densities, isolated pairs of individuals reciprocally spawn with each other, achieving equal current reproductive success. At intermediate group sizes, harems form, with the largest individual typically losing all of its female function and becoming a functional male. In harems, subordinate hermaphrodites obtain little male reproductive success through streaking, an alternative male mating tactic. The lone pure male maintains almost total monopolization of male reproductive success in harems, apparently due to aggressive domination of subordinates. At high group sizes, the ability of the male to monopolize all of the matings in a social group decreases, and some of the larger hermaphrodites obtain some male-role reproductive success by pair spawning with smaller subordinate hermaphrodites while continuing to spawn as females with the male. Mating partners stay relatively constant through time, resulting in a pattern of small 'sub-harems' within harems. These mating tactics are consistent with the hypothesis that dominant individuals increase their current reproductive success in this species by restricting male mating opportunities of conspecifics. Subordinate individuals spawn as males when the dominant is unable to restrict interactions between hermaphrodites that are potential mates, or when they successfully streak. The increased male reproductive success of hermaphrodites in isolated pairs and complex harems compared with hermaphrodites in harems appears to be important in maintaining a hermaphroditic subordinate phenotype in this largely non-reciprocating species.

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