Alternative Male Mating Tactics in a Thrips: Effects of Sex Ratio Variation and Body Size

1988 ◽  
Vol 119 (1) ◽  
pp. 83 ◽  
Author(s):  
Bernard J. Crespi
2020 ◽  
Vol 131 (4) ◽  
pp. 880-897
Author(s):  
Andrew I Furness ◽  
Andres Hagmayer ◽  
Bart J A Pollux

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.


Behaviour ◽  
2010 ◽  
Vol 147 (11) ◽  
pp. 1431-1442 ◽  
Author(s):  
James Cureton II ◽  
Raelynn Deaton ◽  
Rachel Martin

AbstractShort term fluctuations in operational sex ratio (OSR) and density can strongly influence male mating, often exacerbating conflict between males and females. Livebearing fishes of the genus Gambusia are ideal for investigating sexual conflict because males of all sizes mate coercively. In this study, we tested how short-term fluctuations in OSR and density influence coercive male mating behaviours. Specifically, we tested the prediction that as OSR becomes more female biased, males will mate with all available females. In contrast, as OSR becomes more male biased, male aggression will inhibit mating frequency. As predicted, males mated with more females as the number of available females increased. Moreover, males were less aggressive as the proportion of females increased and more aggressive as the number of males increased. This resulted in an inverse relationship between mating and aggression with OSR and density. Coercive males attempt to maximize their reproductive success by mating with all available females, which supports classic theory on the impact of OSR and density on reproductive activity.


1992 ◽  
Vol 70 (9) ◽  
pp. 1652-1655 ◽  
Author(s):  
William D. Brown ◽  
Ruth Stanford

Male blister beetles Nemognatha nitidula employ alternative postmating tactics. Females oviposit on the underside of closed thistle buds, and males actively search these sites for potential mates. Males at the oviposition site guard their mates for an extended period after mating, whereas males that secure copulations at open flowers (the foraging site) forgo mate guarding. On average, guarded females were larger than both females that mated at the foraging site and nonguarded females at the oviposition site. This suggests that a male's choice of mating tactic is contingent on female body size. However, larger females take longer to oviposit, and so a large-phenotype bias among guarded females may be a consequence of males remaining with mates until all eggs are laid. This was not the case; males often terminated guarding before oviposition ended, and there was no correlation between length of the guarding period and female body size. Thus, male mating tactics in this blister beetle vary with both the female's location (which is indicative of her readiness to oviposit) and her body size.


2005 ◽  
Vol 16 (3) ◽  
pp. 541-549 ◽  
Author(s):  
Damian C. Lidgard ◽  
Daryl J. Boness ◽  
W. Don Bowen ◽  
Jim I. McMillan

2003 ◽  
Vol 81 (7) ◽  
pp. 1257-1268 ◽  
Author(s):  
Adrienne I Kovach ◽  
Roger A Powell

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.


2021 ◽  
Author(s):  
Konrad Lipkowski ◽  
Sophie Steigerwald ◽  
Lisa M Schulte ◽  
Carolin Sommer-Trembo ◽  
Jonas Jourdan

Abstract The extent of male mate choosiness is driven by a trade-off between various environmental factors associated with the costs of mate acquisition, quality assessment and opportunity costs. Our knowledge about natural variation in male mate choosiness across different populations of the same species, however, remains limited. In this study, we compared male mate choosiness across 10 natural populations of the freshwater amphipod Gammarus roeselii (Gervais 1835), a species with overall high male mating investments, and evaluated the relative influence of population density and sex ratio (both affecting mate availability) on male mate choosiness. We investigated amplexus establishment after separating mating pairs and presenting focal males with a novel, size-matched female from the same population. Our analysis revealed considerable effects of sex ratio and (to a lesser extent) population density on time until amplexus establishment (choosiness). Male amphipods are able to perceive variable social conditions (e.g., sex ratio) and modify their mating strategy accordingly: We found choosiness to be reduced in increasingly male-biased populations, whereas selectivity increases when sex ratio becomes female biased. With this, our study expands our limited knowledge on natural variations in male mate choosiness and illustrates the importance of sex ratio (i.e., level of competition) for male mating decisions in natural environments. Accounting for variation in sex ratios, therefore, allows envisioning a distinctive variation of choosiness in natural populations and highlights the importance of considering social background information in future behavioral studies.


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