Copulation duration and probability of insemination in Anthocoris whitei (Hemiptera: Anthocoridae) as a function of male body size

2001 ◽  
Vol 133 (1) ◽  
pp. 109-117 ◽  
Author(s):  
David R. Horton ◽  
Tamera M. Lewis ◽  
Tonya Hinojosa
Keyword(s):  
Body Size ◽  
Relative Size ◽  
Copulation Duration ◽  
Male Body ◽  
Male Size ◽  
Male And Female ◽  
Female Body Size ◽  
Duration Of Copulation ◽  
Two Temperatures ◽  
Increasing Temperature

AbstractThe influence of male and female body size on copulation duration and probability of insemination was determined for Anthocoris whitei Reuter allowed to mate at two temperatures. Copulation duration decreased significantly with increasing male length or increasing relative size (male length divided by female length). Female length had no effect on copulation duration. We interrupted copulation at 20 or 40 min at both 25 and 15 °C to determine the interacting effects of male size, temperature, and copulation duration on probability of insemination. Insemination probabilities increased with increasing male size, increasing temperature, and increased duration of copulation. Large males were more successful than small males at inseminating females at cool temperatures and for severely shortened copulations. Results are consistent with the hypothesis that males of this species experience physical difficulties either in achieving intromission or in forcing sperm through the aedeagus, and that larger body size in males lessens these difficulties.

scholarly journals Mate Choice and Copulation Frequency in the Burying BeetleNicrophorus quadripunctatus(Coleoptera: Silphidae): Effect of Male Body Size and Presence of a Rival

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Seizi Suzuki
Keyword(s):  
Body Size ◽  
Mate Choice ◽  
Significant Interaction ◽  
Copulation Duration ◽  
Male Body ◽  
Male Size ◽  
High Quality ◽  
Male Body Size ◽  
Rival Male

It is widely assumed that there exists a competition between males for mating and that females prefer males with elaborate male traits. Further, such traits are considered to be synonymous with high quality in terms of benefits to females. The number and duration of copulations and the frequency of mate refusal between large and smallNicrophorus quadripunctatusmales were examined both for single males and for two males competing. The number of copulations was not affected by the size of the male or by the presence of a rival, but there was a significant interaction such that large males increased their number of copulations when a small rival was present. Copulation duration was not affected by male size but was shortened by a rival male. Females rejected copulation attempts of small males more often than of large males, whether the males were alone or paired with a rival. These results suggest that large males have two advantages: they win contests between males and are preferred by females.

Geographic variation in body size and sexual size dimorphism of North American Ratsnakes (Pantherophis spp. s.l.)

2018 ◽  
Vol 96 (11) ◽  
pp. 1196-1202 ◽  
Author(s):  
Brett A. DeGregorio ◽  
Gabriel Blouin-Demers ◽  
Gerardo L.F. Carfagno ◽  
J. Whitfield Gibbons ◽  
Stephen J. Mullin ◽  
...  
Keyword(s):  
Body Size ◽  
Large Scale ◽  
Sexual Size Dimorphism ◽  
Size Variation ◽  
Sexually Dimorphic ◽  
Male Body ◽  
Complex Species ◽  
Size Dimorphism ◽  
Body Size Variation ◽  
Female Body Size

Because body size affects nearly all facets of an organism’s life history, ecologists have long been interested in large-scale patterns of body-size variation, as well as why those large-scale patterns often differ between sexes. We explored body-size variation across the range of the sexually dimorphic Ratsnake complex (species of the genus Pantherophis Fitzinger, 1843 s.l.; formerly Elaphe obsoleta (Say in James, 1823)) in North America. We specifically explored whether variation in body size followed latitudinal patterns or varied with climatic variables. We found that body size did not conform to a climatic or latitudinal gradient, but instead, some of the populations with the largest snakes occurred near the core of the geographic range and some with the smallest occurred near the northern, western, and southern peripheries of the range. Males averaged 14% larger than females, although the degree of sexual size dimorphism varied between populations (range: 2%–25%). There was a weak trend for male body size to change in relation to temperature, whereas female body size did not. Our results indicate that relationships between climate and an ectotherm’s body size are more complicated than linear latitudinal clines and likely differ for males and females.

scholarly journals Brood Sex Ratios are Related to Male Size but not to Attractiveness in Common Yellowthroats (Geothlypis Trichas)

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 176-184 ◽  
Author(s):  
Betsy Abroe ◽  
Julia C. Garvin ◽  
Marc C. Pedersen ◽  
Linda A. Whittingham ◽  
Peter O. Dunn
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Reproductive Value ◽  
Male Body ◽  
Male Size ◽  
Common Yellowthroat ◽  
Geothlypis Trichas ◽  
The Common ◽  
Fitness Benefits ◽  
Male Ornament

Abstract When the reproductive value of sons differs from that of daughters, selection will favor broods biased toward the sex that can provide greater fitness benefits. In species where female choice is based on male ornamentation, females mated to highly ornamented males may experience a reproductive advantage by skewing the brood sex ratio toward sons. In the Common Yellowthroat (Geothlypis trichas), males with larger black facial masks are more likely to gain a social mate and sire extrapair young and, as a result, have increased seasonal reproductive success. Females mated to larger-masked males could benefit if they produced more sons. Given that larger- masked males are preferred as extrapair sires, females may also benefit by producing more extrapair sons. We tested these hypotheses during a five-year study of Common Yellowthroats in Wisconsin. Contrary to our predictions, females did not produce more sons when mated to males with larger masks, and extrapair young were not more likely to be male. However, sons were more likely to be sired by males with longer tarsi, which suggests that females may respond to male body size rather than to male ornament size. El Cociente de Sexos en las Nidadas Está Relacionado con el Tamaño de los Machos pero no con el Atractivo en Geothlypis trichas

Variation in reproductive characteristics of the stream frog Colostethus trinitatis on the island of Trinidad

1995 ◽  
Vol 11 (4) ◽  
pp. 603-618 ◽  
Author(s):  
Clive P. Cummins ◽  
Mary J. S. Swan
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Adult Female ◽  
Physical Environment ◽  
Male Body ◽  
Selective Predation ◽  
Reproductive Characteristics ◽  
Female Body Size ◽  
Forest Stream ◽  
Proximate Causes

ABSTRACTWe compared reproductive characteristics of the dendrobatid frog Colostethus trinitatis at the Tamana cave in the Central Range hills and at five forest stream sites in the Northern Range hills of Trinidad. There were significant differences between sites in adult female body size, intraovarian clutch size (in absolute terms and relative to body size) and the size of tadpoles carried by male frogs. Clutch sizes ranged from 6 to 13 in the Northern Range samples and from 12 to 26 at Tamana. Adult male body size was similar at all sites. Tadpoles carried by male C. trinitatis at Tamana were significantly smaller (mean length 14.2 mm) than those carried by males at the five Northern range sites (mean length 16.4–16.7 mm). The smallest clutches and largest tadpoles were found at Mount St Benedict, where there was evidence of size-selective predation on tadpoles by fish. Tamana, where clutches were large and tadpoles small, differed from the Northern Range sites in terms of the physical environment (cave vs forest) and the abundance of invertebrates. We discuss possible ultimate and proximate causes of the differences in clutch size and tadpole size, particularly size-selective predation and availability of food.

Monogamy in the European Starling

Behaviour ◽  
1992 ◽  
Vol 120 (3-4) ◽  
pp. 262-285 ◽  
Author(s):  
Innes Cuthill ◽  
Jonathan Wright
Keyword(s):  
Body Size ◽  
Experimental Studies ◽  
Nest Defence ◽  
Female Size ◽  
European Starlings ◽  
Male And Female ◽  
Female Body Size ◽  
Relative Contribution ◽  
Provisioning Rate ◽  
Male Display

AbstractRecent theoretical and experimental studies appear to provide a comprehensive explanation for the evolutionary, and short-term, stability of biparental care in birds. However, much of the intraspecific variation in the absolute and relative contribution by the male and female remains to be explained. Most studies of the natural variation across pairs reveal positive correlations between the level of male and female nest defence or brood provisioning, but some species show negative relations, or between-season variability in the direction of the relationship. This study examines the determinants of male and female provisioning rate in monogamous European starlings (Sturnus vulgaris), in terms of the patterns of male display, pairing patterns, laying phenology and clutch attributes. There was assortative pairing by body size and, controlling for female body size, larger males attracted relatively fecund mates. Males that sang relatively more, controlling for these body size effects, were paired with females that laid earlier. Female nest provisioning rates to experimentally standardized broods were positively correlated with female size, but male provisioning rates were unrelated to either song or any other attributes of themselves or their mates.

Egg size, prey size, and sexual size dimorphism in digger wasps (Hymenoptera: Sphecidae)

1985 ◽  
Vol 63 (9) ◽  
pp. 2187-2193 ◽  
Author(s):  
Kevin M. O'Neill
Keyword(s):  
Body Size ◽  
Selection Pressure ◽  
Sexual Size Dimorphism ◽  
Species Selection ◽  
Male Size ◽  
Size Dimorphism ◽  
Female Body Size ◽  
Mean Size ◽  
Males And Females ◽  
Apparent Association

Female digger wasps invest substantially in each of their offspring, laying relatively few, large eggs and providing the young with the insect prey on which they depend for food. In a study of six species in the genera Philanthus, Bembecinus, and Bembix, it was found that within each species, there is a positive correlation between female body size and both the size of their ovarial eggs and the size of the prey they provision. In five of the six species, females were larger than males on average. It is suggested that the apparent association between body size and certain aspects of parental investment by females may provide the directional selection pressure that results in the evolution of sexual size dimorphism in digger wasps. In one species, males and females have the same mean size, probably because, in this species, selection pressure on male size is similar to that on females.

scholarly journals Male size does not correlate with fertilization success in two bufonid toads that show size-assortative mating

2013 ◽  
Vol 59 (6) ◽  
pp. 740-746 ◽  
Author(s):  
Xiao-Li Fan ◽  
Zhi-Hua Lin ◽  
Xiang Ji
Keyword(s):  
Body Size ◽  
Assortative Mating ◽  
Clutch Size ◽  
Egg Size ◽  
Dry Mass ◽  
Fertilization Success ◽  
Male Body ◽  
Mating Pattern ◽  
Male Size ◽  
Male Preference

Abstract We examined sexual size dimorphism (SSD), mating pattern, fertilization efficiency and female reproductive traits in two bufonid toads (Bufo gargarizans and Duttaphrynus melanostictus) to test the idea that importance of male body size for egg fertilization success depends on the mating pattern. Female-biased SSD was evident only in D. melanostictus. Female B. gar-garizans laid fewer larger eggs nearly three months earlier than did female D. melanostictus. Fertilization efficiencies on average were higher in B. gargarizans (95%) than in D. melanostictus (91%). Though differing in the degree of SSD, body size, breeding season, clutch size, egg size and fertilization efficiency, the two toads were similar in four aspects: (1) both showed size-assortative mating; (2) females did not tradeoff egg size against egg number; (3) male size, clutch size and clutch dry mass were greater in male-larger than in female-larger pairs after accounting for female snout-vent length (SVL); and (4) the ratio of male to female SVL did not affect fertilization efficiency. Our data show that: (1) a female preference for large males is likely not important in terms of egg fertilization success; (2) a male preference for large females is likely important because larger females are more fecund; and (3) size-assortative mating arises from a male preference for large females. Our study demonstrates that male size is not always important for egg fertilization success in anurans that show size-assortative mating.

scholarly journals Benefits of size dimorphism and copulatory silk wrapping in the sexually cannibalistic nursery web spider, Pisaurina mira

2016 ◽  
Vol 12 (2) ◽  
pp. 20150957 ◽  
Author(s):  
Alissa G. Anderson ◽  
Eileen A. Hebets
Keyword(s):  
Body Size ◽  
Relative Size ◽  
Male Reproductive Success ◽  
Male Fitness ◽  
Male Size ◽  
Treatment Groups ◽  
Web Spider ◽  
Sexually Selected Traits ◽  
Mate Acquisition ◽  
Selected Traits

In sexually cannibalistic animals, male fitness is influenced not only by successful mate acquisition and egg fertilization, but also by avoiding being eaten. In the cannibalistic nursery web spider, Pisaurina mira , the legs of mature males are longer in relation to their body size than those of females, and males use these legs to aid in wrapping a female's legs with silk prior to and during copulation. We hypothesized that elongated male legs and silk wrapping provide benefits to males, in part through a reduced likelihood of sexual cannibalism. To test this, we paired females of random size with males from one of two treatment groups—those capable of silk wrapping versus those incapable of silk wrapping. We found that males with relatively longer legs and larger body size were more likely to mate and were less likely to be cannibalized prior to copulation. Regardless of relative size, males capable of silk wrapping were less likely to be cannibalized during or following copulation and had more opportunities for sperm transfer (i.e. pedipalpal insertions). Our results suggest that male size and copulatory silk wrapping are sexually selected traits benefiting male reproductive success.

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