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.

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.

scholarly journals Size-dependent male mating tactics and their morphological correlates in Poecilia gillii

2020 ◽  
Vol 131 (4) ◽  
pp. 880-897
Author(s):  
Andrew I Furness ◽  
Andres Hagmayer ◽  
Bart J A Pollux
Keyword(s):  
Body Size ◽  
Reproductive Strategies ◽  
Mating Behaviour ◽  
A Priori ◽  
Male Mating ◽  
Mating Tactics ◽  
Male Size ◽  
Size Dependent ◽  
Chemical Factors ◽  
Size And Morphology

Abstract Male alternative reproductive strategies are found in some species of most major animal taxa but are especially widespread in fishes. Mature males of the shortfin molly, Poecilia gillii, display extensive variation in size and morphology. We devised a field test of a priori hypotheses regarding the interrelationships between male size, coloration, morphology and mating tactics. Males did not occur in discrete size classes, but instead occurred in a size and morphological continuum. Large males exhibited darker and more orange-coloured dorsal and caudal fins, whereas small males exhibited lighter and more inconspicuous fin coloration. Furthermore, larger males had proportionately deeper bodies, larger dorsal and caudal fins and shorter gonopodia than smaller males. Our field study of male mating behaviour revealed a lack of courtship in this species, and similar levels of mating attempts (gonopodial thrusts) irrespective of male size. Instead, small males were significantly more likely to chase females than were large males. In contrast, large males exhibited higher rates of gonoporal nibbling (a likely means by which males determine, through chemical factors, whether a female is carrying fertilizable ova) and higher likelihood of chasing other males away. In total, we found evidence for the predicted associations between male size, coloration, morphology and mating behaviour. These associations appear likely to maximize mating success for males of a given body size and phenotype.

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.

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 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.

No experimental effects of parasite load on male mating behaviour and reproductive success

2011 ◽  
Vol 82 (4) ◽  
pp. 673-682 ◽  
Author(s):  
Shirley Raveh ◽  
Dik Heg ◽  
F. Stephen Dobson ◽  
David W. Coltman ◽  
Jamieson C. Gorrell ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Mating Behaviour ◽  
Parasite Load ◽  
Male Mating
Sign in / Sign up

Export Citation Format

Share Document