scholarly journals Lifetime Reproductive Success of Female Eastern Kingbirds (Tyrannus Tyrannus): Influence of Lifespan, Nest Predation, and Body Size

The Auk ◽  
2007 ◽  
Vol 124 (3) ◽  
pp. 1010-1022 ◽  
Author(s):  
Michael T. Murphy
Keyword(s):  
New York ◽  
Body Size ◽  
Reproductive Success ◽  
Clutch Size ◽  
Small Body ◽  
Cost Of Reproduction ◽  
Large Female ◽  
Lifetime Reproductive Success ◽  
Female Size ◽  
Tyrannus Tyrannus

AbstractI report on the lifetime reproductive success (LRS) of female Eastern Kingbirds (Tyrannus tyrannus) in central New York. I investigated the major correlates of LRS and specifically tested the hypothesis that small body size yields reproductive benefits. Lifetime reproductive success varied widely: 15–20% of females failed to fledge young over their life, whereas 50% of young were fledged by 20% of females. Female lifespan varied between one and eight years, and females that died after one breeding season tended to be smaller-bodied than long-lived females (≥2 seasons). I therefore conducted analyses of LRS for the entire sample and for longer-lived females separately. As in other species, lifespan was the strongest predictor of LRS, followed by the proportion of eggs laid that resulted in fledged young (P). Lifetime reproductive success varied positively with clutch size and, as predicted, inversely with body size (i.e., tarsus length) of females. However, variance partitioning indicated that most variation in LRS was attributable to the effects of lifespan and P, but that a substantial negative covariance existed between lifespan and P. The latter result was consistent with experimental evidence of a cost of reproduction in Eastern Kingbirds. Analysis of the correlates of lifespan, P, and clutch size showed that over a female's lifetime, (1) the longest-lived birds fledged an intermediate proportion of the eggs that they laid, (2) the most productive birds were of intermediate wing length, and (3) females with small tarsi produced the largest clutches and lost the fewest nests to predators. Hence, although lifespan was the dominant influence on LRS, negative effects of large female size appeared to be expressed through the influence of body size on other demographic parameters that contribute to LRS.Éxito Reproductivo Completo de Vida de Hembras de Tyrannus tyrannus: Influencia de la Duración de la Vida, la Depredación de Nidos y el Tamaño Corporal

Maximizing male reproductive success in the broad-headed skink (Eumeces laticeps): preliminary evidence for mate guarding, size-assortative pairing, and opportunistic extra-pair mating

1997 ◽  
Vol 18 (1) ◽  
pp. 59-73 ◽  
Author(s):  
William E. Cooper ◽  
Laurie J. Vitt
Keyword(s):  
Reproductive Success ◽  
Clutch Size ◽  
Mate Guarding ◽  
Preliminary Evidence ◽  
Large Female ◽  
Male Reproductive Success ◽  
Female Size ◽  
Male Preference ◽  
Eumeces Laticeps ◽  
Assortative Pairing

AbstractSeveral lines of evidence suggest that male Eumeces laticeps may increase reproductive success by 1) mating with larger females to increase clutch size, 2) mate guarding to be present during the female's receptive period and/or prevent sperm competition, and 3) engaging in extra-pair copulations. Clutch size increases with female body size, establishing a potential advantage of male preference for large female mates. Mate association lasts up to 8 days and possibly longer, with a mean of nearly 5 days. Males may remain with females during a major portion of the mating season, which preliminary data suggest lasts about two weeks, suggesting that mate-guarding may reduce the level of polygyny. Tethered introductions of intruder males to consort pairs showed that consort males use aggressive behavior to exclude other males from the vicinity of females. Eumeces laticeps exhibits strong positive size-assortative pairing, suggesting the possible importance of male choice of large mates. Female preference for large males could account for this relationship, but only if large females prefer the largest possible males within the acceptable size range and aggressively exclude other females from preferred males. Females are sometimes aggressive to each other, especially near nest sites, but aggression is suppressed by males, as shown by tethered introduction of females to consort pairs. Size-assortative pairing may be based in part on male preference if males can prevent larger females from aggressively excluding smaller ones. In addition to preferentially guarding large females, males not currently guarding mate with any females not large enough to deter them aggressively. A field observation of an extra-pair copulation, responses by consort males to introduced females, and the lack of size preference in the absence of consorts suggest that males may engage opportunistically in extra-pair copulations to increase reproductive success and are not then choosy about female size.

Evolution of sexual dimorphism in the plateau brown frog fails to obey Rensch’s rule

2022 ◽  
pp. 27-33
Author(s):  
Tong Lei Yu
Keyword(s):  
Body Size ◽  
Large Male ◽  
Large Female ◽  
Female Size ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Males And Females ◽  
Brown Frog ◽  
Using Data

Rensch’s rule describes sexual size dimorphism (SSD) that decreases with increasing body size when females are larger than males and SSD that increases when males are larger than females. The plateau brown frog Rana kukunoris, a species endemic to the eastern Tibetan Plateau, exhibits female-biased size dimorphism. Using data on body size from 26 populations and age from 21 populations, we demonstrated that SSD did not increase with increasing mean female snout-vent length (SVL) when controlling for sex-specific age structure, failing to support the Rensch’s rule. Thus, we suggest that fecundity selection (favouring large female size) balances out sexual selection (favouring large male size), which results in a similar divergence between males and females body size. In addition, sex-specific age differences explained most of the variation of SSD across populations.

Body size, age distribution, and reproduction in a northern population of wood turtles (Clemmys insculpta)

1992 ◽  
Vol 70 (3) ◽  
pp. 462-469 ◽  
Author(s):  
Ronald J. Brooks ◽  
Cathy M. Shilton ◽  
Gregory P. Brown ◽  
Norman W. S. Quinn
Keyword(s):  
Body Size ◽  
Clutch Size ◽  
Partial Correlation ◽  
Age Distribution ◽  
Egg Mass ◽  
Female Size ◽  
After Effects ◽  
Mean Width ◽  
Wood Turtles ◽  
Provincial Park

A population of the wood turtle (Clemmys insculpta) was studied on the east side of Algonquin Provincial Park, Ontario, from 1987 to 1990. A total of 77 adults (56 females, 21 males) and 13 juveniles were captured, measured, and individually marked. Age at maturity was 17–18 years at a minimum carapace length of 185 mm for females and 199 mm for males. Our data supported the hypothesis that turtles in northern populations are larger and older at maturity than are those in southern populations. For 21 nests, mean clutch size was 8.8 eggs and egg mass was 96 g. Predators destroyed 15 of 17 nests in 1990, and had injured 60% of adult turtles observed. Therefore, our population had low recruitment, few juveniles, and high levels of predation on nests and adults. Comparisons among females refuted two predictions from optimal egg size theory. Mean width and mass, but not length, of eggs correlated positively with female size, and correlated positively with clutch size, even after effects of body size were removed by partial correlation. However, smaller females in the population had relatively longer eggs than did larger females, whereas the Algonquin females have absolutely smaller eggs than do much smaller females in a New Jersey population.

Variation in incubation length and hatching asynchrony in Eastern Kingbirds: Weather eclipses female effects

The Auk ◽  
2021 ◽  
Author(s):  
Samantha M Gillette ◽  
Amanda L Klehr ◽  
Michael T Murphy
Keyword(s):  
New York ◽  
Clutch Size ◽  
Egg Laying ◽  
Hatching Asynchrony ◽  
Ambient Temperatures ◽  
Temperature And Precipitation ◽  
Incubation Periods ◽  
Tyrannus Tyrannus ◽  
Eastern Kingbird ◽  
Small Clutch

Abstract Incubation length and hatching asynchrony are integral elements of the evolved reproductive strategies of birds. We examined intra- and interpopulation variation in both traits for Eastern Kingbird (Tyrannus tyrannus) populations from New York (NY), Kansas (KS), and Oregon (OR) and found that both incubation length and hatching asynchrony were not repeatable among females, after controlling for a repeatable trait, clutch size. Instead, incubation length and clutch size were influenced by ambient temperature and precipitation. Incubation length exhibited the same median (15 days) and range (13–17 days) at all sites. Model selection results indicated that incubation periods for the smallest and largest clutches were longer in NY than KS when rain was frequent throughout incubation, in replacement nests, and likely when ambient temperatures were low during egg-laying. Full hatching usually required 2 days (but up to 3), with synchronous hatching associated with small clutch sizes, short incubation periods, frequent rain during the egg-laying period, and low ambient temperatures during the first half of incubation. Nestling starvation was uncommon (5–9% of nestlings monitored) and not associated with greater hatching asynchrony. These results indicate that while clutch size, a repeatable female trait, contributed to variation in incubation length and hatching asynchrony in Eastern Kingbirds, weather was a greater source of variation, especially for incubation length.

Influence of female-biased sexual size dimorphism on dominance of female Townsend’s chipmunks

2006 ◽  
Vol 84 (12) ◽  
pp. 1859-1863 ◽  
Author(s):  
A.J. Edelman ◽  
J.L. Koprowski
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
North American ◽  
Sexual Size Dimorphism ◽  
Large Female ◽  
Small Female ◽  
Access To Resources ◽  
Size Dimorphism

Female-biased sexual size dimorphism (SSD), a condition common in North American chipmunks, occurs when females are larger than males in a species. We examined the influence of body size on dominance of captive female Townsend’s chipmunks ( Tamias townsendii Bachman, 1839), a species that exhibits female-biased SSD, in all-female and mixed-sex dyadic encounters. In all-female dyads, large female chipmunks were more frequently dominant over small female opponents. In mixed-sex dyads, large females were always dominant over small males. Female-biased SSD in Townsend’s chipmunks appears to indirectly allow large females to more frequently dominate small female and male conspecifics. Greater dominance could increase reproductive success of large female chipmunks by increasing access to resources.

Body size is associated with yearling breeding and extra-pair mating in the Island Scrub-Jay

The Auk ◽  
2021 ◽  
Author(s):  
Michelle A Desrosiers ◽  
Kathryn M Langin ◽  
W Chris Funk ◽  
T Scott Sillett ◽  
Scott A Morrison ◽  
...  
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Large Body ◽  
Lifetime Reproductive Success ◽  
Large Body Size ◽  
Individual Fitness ◽  
Fitness Advantage ◽  
Breeding Territory ◽  
Pair Mating ◽  
Extra Pair Mating

Abstract Large body size is an important determinant of individual fitness in many animal species, especially in island systems where habitat saturation may result in strong intraspecific competition for mates and breeding territories. Here we show that large body size is associated with benefits to yearling breeding and extra-pair mating in the Island Scrub-Jay (Aphelocoma insularis), endemic to Santa Cruz Island, California. This species is ~20% larger than its mainland congener, consistent with the island syndrome, indicating that body size may be a trait under selection. From 2009 to 2013, we quantified the reproductive success of a marked population of Island Scrub-Jays, tracked which yearlings acquired a breeding territory and bred, and measured the occurrence of extra-pair paternity. Two potential contributors to fitness were positively related to body size. Larger yearling males were more likely to breed, possibly due to greater behavioral dominance during aggressive encounters. Larger males were also less likely to lose paternity to extra-pair males and, anecdotally, extra-pair males were larger than the social male cuckolded. This study provides evidence that larger males may have a fitness advantage over smaller males by breeding earlier and avoiding paternity loss, but estimates of lifetime reproductive success are ultimately needed for Island Scrub-Jays and other long-lived species.

Male body size affects female lifetime reproductive success in a seed beetle

1995 ◽  
Vol 50 (1) ◽  
pp. 281-284 ◽  
Author(s):  
CHARLES W. FOX ◽  
LAURIE A. McLENNAN ◽  
TIMOTHY A. MOUSSEAU
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Lifetime Reproductive Success ◽  
Male Body ◽  
Seed Beetle ◽  
Male Body Size
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