Effects of body size divergence on male mating tactics in the ground beetle Carabus japonicus

Evolution ◽  
2021 ◽  
Author(s):  
Yutaka Okuzaki
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.


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.


Biologia ◽  
2017 ◽  
Vol 72 (9) ◽  
Author(s):  
Aleksandra Cvetkovska-Gjorgjievska ◽  
Slavčo Hristovski ◽  
Dana Prelić ◽  
Lucija Šerić Jelaska ◽  
Valentina Slavevska-Stamenković ◽  
...  

AbstractCarabid fauna is not sufficiently explored in Central and Western Balkan areas, especially in mountain ecosystems with unique biodiversity which is a result of specific environmental factors and geologic history. Furthermore, distribution of species and adaptation to varying environmental parameters change along the altitudinal gradients. All this highlights the need for biodiversity and ecological studies in order to assess the state of the mountain ecosystems and conservation significance. Carabids as good bioindicator group can be used as a tool for monitoring those changes. The aim of this study was to analyse the differences of body size distribution and mean individual biomass (MIB) of ground beetle assemblages as a response of changing conditions and vegetation types along an altitudinal gradient on Belasitsa Mountain in south Macedonia. Both parameters significantly decreased with increasing altitude and were consequently associated with the vegetation type. Larger bodied individuals and higher values of MIB were recorded in the white oak and oriental hornbeam forest stands with the values decreasing in sessile oak forests towards submontane and montane beech forest stands. This research yielded first list of carabid species inhabiting Belasitsa Mountain with insight of carabid body length and biomass distribution along altitudinal gradient.


2005 ◽  
Vol 83 (12) ◽  
pp. 1638-1642 ◽  
Author(s):  
Albrecht I Schulte-Hostedde ◽  
Gary Burness

Sperm competition results in the evolution of ejaculate characteristics such as high sperm density, high motility, and fast sperm swimming speed. A fundamental assumption of sperm competition theory is that ejaculates with high motility and fast-swimming sperm have an advantage with respect to fertilization success. We tested this assumption by studying the fertilization dynamics of alternative mating tactics (cuckolders and parentals) of male bluegill (Lepomis macrochirus Rafinesque, 1819). Sneakers (cuckolders) have faster swimming sperm and a higher proportion of motile sperm immediately following sperm activation than do parentals; however, these variables decline more quickly over time in sneaker sperm than in the sperm of parental males. We used a controlled fertilization experiment to test the prediction that parental males will have higher fertilization success than sneakers late in the sperm activation cycle because of the reduced rate of decline in ejaculate quality over time. We found that as the time from sperm activation increases parental sperm fertilizes more eggs than the sperm of sneakers. Our results support the idea that fertilization success is higher when ejaculates contain a higher proportion of either motile sperm or faster swimming sperm, all else being equal. In addition, after controlling for time from sperm activation, we found a significant bias in fertilization success toward parental males, suggesting that cryptic female choice might play a role in fertilization dynamics.


2012 ◽  
Vol 153 (4) ◽  
pp. 999-1009 ◽  
Author(s):  
D. E. Chamberlain ◽  
M. Bocca ◽  
L. Migliore ◽  
E. Caprio ◽  
A. Rolando

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