scholarly journals Surplus nest boxes and the potential for polygyny affect clutch size and offspring sex ratio in house wrens

2006 ◽  
Vol 273 (1595) ◽  
pp. 1751-1757 ◽  
Author(s):  
Natalie S Dubois ◽  
E Dale Kennedy ◽  
Thomas Getty
Keyword(s):  
Reproductive Investment ◽  
Male Reproductive Success ◽  
Offspring Sex Ratio ◽  
House Wrens ◽  
Nest Boxes ◽  
Cavity Nesting ◽  
Offspring Sex ◽  
Investment In Reproduction ◽  
Male House

Females of many species can gain benefits from being choosy about their mates and even exhibit context-dependent investment in reproduction in response to the quality of their breeding situation. Here, we show that if a male house wren is provided with surplus nest boxes in his territory, his mate lays a larger clutch with a significantly higher proportion of sons. This response to a territory characteristic directly associated with male competitive ability, and ultimately to male reproductive success, suggests that male competition over access to high-quality territories with surplus nest boxes (i.e. those able to support polygyny) may influence female reproductive investment decisions. The results of this study have interesting implications, particularly considering the important role that studies of cavity nesting birds utilizing nest boxes have played in advancing our understanding of behaviour, ecology and evolution.

scholarly journals Maternal Condition, Reproductive Investment, and Offspring Sex Ratio in Captive Red Junglefowl (Gallus gallus)

The Auk ◽  
2002 ◽  
Vol 119 (3) ◽  
pp. 840-845 ◽  
Author(s):  
Timothy H. Parker
Keyword(s):  
Reproductive Success ◽  
Egg Size ◽  
Reproductive Investment ◽  
Gallus Gallus ◽  
Male Reproductive Success ◽  
Maternal Condition ◽  
Offspring Sex Ratio ◽  
Red Junglefowl ◽  
Offspring Sex ◽  
The Relationship

Abstract Maternal condition can affect reproductive investment in one or more ways. Captive female Red Junglefowl (Gallus gallus) that were heavier, controlling for tarsus length, produced larger eggs and initiated laying earlier, but did not produce more eggs per clutch. Maternal mass was also a positive predictor of offspring mass. That appears to result from the strong positive relationships between egg size and offspring mass. When the relationship between egg size and offspring mass was statistically controlled, maternal mass no longer predicted offspring mass. Mothers in better condition produced male-biased broods, as predicted when offspring condition depends on maternal condition and when male reproductive success is more dependent than female reproductive success on condition.

Are avian ectoparasites more numerous in nest boxes with old nest material?

1996 ◽  
Vol 74 (10) ◽  
pp. 1819-1825 ◽  
Author(s):  
Wallace B. Rendell ◽  
Nicolaas A. M. Verbeek
Keyword(s):  
Positive Association ◽  
Winter Survival ◽  
Tree Swallow ◽  
Nest Sites ◽  
Nest Boxes ◽  
Cavity Nesting ◽  
Ornithonyssus Sylviarum ◽  
Nest Microclimate ◽  
One Year

Researchers may reduce the numbers of haematophagous ectoparasites in nest boxes of cavity-nesting birds by removing old nests from boxes and, as a result, eliminate an important selective pressure that could influence the results from nest-box studies of birds. We recorded the numbers of parasites in tree swallow (Tachycineta bicolor) boxes in which we manipulated the presence, amount, and quality of old nests. Bird fleas (Ceratophyllus idius) were more numerous in boxes with old nests, and there was a positive correlation between nest volume and flea numbers. In one year, there was a positive association between fowl mite (Ornithonyssus sylviarum) numbers and nest volume; otherwise, fowl mites and blow flies (Protocalliphora sialia) were equally numerous in all nest types. We conclude that ectoparasites whose over-winter survival depends on old nests are more numerous in boxes with old nests, whereas parasites whose over-winter survival is independent of old nests infect nest sites randomly. Also, reinfection and nest microclimate likely contributed to variance in parasite numbers between nest types and years, respectively. We recommend caution when speculating about the possible effects of cleaning boxes on parasites that occur in nests because different species of parasites are not influenced similarly by old nests.

scholarly journals Differential sex allocation in sand lizards: bright males induce daughter production in a species with heteromorphic sex chromosomes

2005 ◽  
Vol 1 (3) ◽  
pp. 378-380 ◽  
Author(s):  
Mats Olsson ◽  
Erik Wapstra ◽  
Tobias Uller
Keyword(s):  
Sex Ratio ◽  
Reproductive Investment ◽  
Experimental Manipulation ◽  
Polymorphism Analysis ◽  
Offspring Sex Ratio ◽  
Heteromorphic Sex Chromosomes ◽  
Offspring Sex ◽  
In The Wild ◽  
Lacerta Agilis ◽  
Energetic Expenditure

In sand lizards ( Lacerta agilis ), males with more and brighter nuptial coloration also have more DNA fragments visualized in restriction fragment length polymorphism analysis of their major histocompatibility complex class I loci (and, hence, are probably more heterozygous at these loci). Such males produce more viable offspring, with a particularly strong viability effect on daughters. This suggests that females should adjust both their reproductive investment and offspring sex ratio in relation to male coloration (i.e. differential allocation). Our results show that experimental manipulation of partner coloration in the wild results in significantly higher maternal effort and a 10% higher proportion of daughters than sons. This supports the hypothesis that females increase their maternal energetic expenditure and adjust their offspring sex ratio in response to high-quality partners. However, it also suggests that this has probably evolved through natural selection for increased offspring viability (primarily through production of daughters), rather than through increased mate attraction (e.g. sexy sons).

Female house wrens value the nest cavity more than exclusive access to males during conflicts with female intruders

Behaviour ◽  
2018 ◽  
Vol 155 (2-3) ◽  
pp. 151-180 ◽  
Author(s):  
Cara A. Krieg ◽  
Thomas Getty
Keyword(s):  
Female Aggression ◽  
Troglodytes Aedon ◽  
High Quality ◽  
House Wren ◽  
Nest Cavity ◽  
House Wrens ◽  
Nest Boxes ◽  
Male Care ◽  
To Receive ◽  
Male House

Abstract Individuals should fight hardest when they stand to lose the most. Whereas males frequently compete for fertile females, females more often compete for high quality males, male care, or resources required to breed. We asked whether established, territorial female house wrens (Troglodytes aedon) challenged by simulated female intruders fight as if they place more value on retaining (1) their nesting cavity or (2) exclusive access to other benefits offered by males. We randomly assigned house wren pairs to receive one or three nest boxes and then assayed female aggression. The relative costs to losing differed between box treatments. For one-box females, the risk of losing the cavity and territory was higher. For three-box females, the risk of losing the cavity may be lower because intruders may be able to settle as secondary females in the supplemental boxes. In this situation, females would lose exclusive access to males and their territories but would still retain the male’s assistance rearing offspring since male house wrens favour their oldest brood. We found that one-box females were significantly more aggressive. This response may be adaptive, as females that switched territories between broods were significantly more likely to lose their entire nest prior to hatching than females that retained the same territory. We interpret our results to mean that female house wrens value the nest cavity more than other benefits from exclusive access to males and their territories. This work contributes to a body of evidence that females often compete for resources required to breed.

scholarly journals Offspring sex ratio varies with clutch size for female house wrens induced to lay supernumerary eggs

2013 ◽  
Vol 25 (1) ◽  
pp. 165-171 ◽  
Author(s):  
E. K. Bowers ◽  
C. F. Thompson ◽  
S. K. Sakaluk
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Offspring Sex Ratio ◽  
House Wrens ◽  
Offspring Sex

scholarly journals Seasonal Variation in Sex Ratios Provides Developmental Advantages in White-tailed Deer, Odocoileus virginianus

2007 ◽  
Vol 121 (4) ◽  
pp. 412
Author(s):  
Sarah T. Saalfeld ◽  
Stephen S. Ditchkoff ◽  
John J. Ozoga ◽  
Michael S. Mitchell
Keyword(s):  
Reproductive Success ◽  
Odocoileus Virginianus ◽  
Mammalian Species ◽  
Sex Ratios ◽  
Reproductive Potential ◽  
Birth Date ◽  
Male Reproductive Success ◽  
Maternal Condition ◽  
Offspring Sex Ratio ◽  
Offspring Sex

Since Trivers and Willard first proposed their hypothesis concerning the adaptive advantages of producing a particular offspring sex in relation to maternal condition in 1973, it has been at the forefront of scientific research concerning sex ratios with most subsequent studies focusing on maternal condition as a key contributor to variations in sex ratios. Another factor that could greatly influence sex ratios, although has been only infrequently examined in mammalian species, is birth date. We investigated how birth date influenced offspring sex ratios in White-tailed Deer (Odocoileus virginianus). Since date of birth can greatly influence an individual’s fitness and reproductive success, we suggest that birth date may be an alternative strategy in determining offspring sex ratios. Since it has been shown that the lifetime reproductive fitness of a mother can be increased by producing a particular sex during a particular time, we hypothesized that more male offspring should be born earlier in the season due to their increased reproductive potential from being born at this time. Offspring born earlier will have a head start in development and therefore have greater potential for increased body size and dominance later in life, traits that greatly influence male reproductive success. In this study, we found that maternal condition did not affect offspring sex ratio in a captive population of White-tailed Deer in Michigan; however, birth date did. We found that more males tended to be born during the second and fourth birthing periods, while more females were born during the first, third and fifth periods. In addition, we found that males born earlier in the season had greater mass the following spring than those born later, a trend that was not as dramatic in females. These results lend moderate support to our hypothesis that in White-tailed Deer offspring sex will tend to vary according to timing of birth and relative reproductive advantages gained by a particular sex being born at that time.

scholarly journals Microclimate Temperatures Impact Nesting Preference in Megachile rotundata (Hymenoptera: Megachilidae)

2020 ◽  
Vol 49 (2) ◽  
pp. 296-303 ◽  
Author(s):  
Elisabeth S Wilson ◽  
Claire E Murphy ◽  
Joseph P Rinehart ◽  
George Yocum ◽  
Julia H Bowsher
Keyword(s):  
Reproductive Investment ◽  
Solitary Bee ◽  
Megachile Rotundata ◽  
Nest Boxes ◽  
The North ◽  
Cavity Nesting ◽  
Alfalfa Field ◽  
3D Printed ◽  
Maximum Temperatures ◽  
Temperature Impacts

Abstract The temperature of the nest influences fitness in cavity-nesting bees. Females may choose nest cavities that mitigate their offspring’s exposure to stressful temperatures. This study aims to understand how cavity temperature impacts the nesting preference of the solitary bee Megachile rotundata (Fabricius) under field conditions. We designed and 3D printed nest boxes that measured the temperatures of 432 cavities. Nest boxes were four-sided with cavity entrances facing northeast, northwest, southeast, and southwest. Nest boxes were placed along an alfalfa field in Fargo, ND and were observed daily for completed nests. Our study found that cavity temperature varied by direction the cavity faced and by the position of the cavity within the nest box. The southwest sides recorded the highest maximum temperatures while the northeast sides recorded the lowest maximum temperatures. Nesting females filled cavities on the north-facing sides faster than cavities on the south-facing sides. The bees preferred to nest in cavities with lower average temperatures during foraging hours, and cavities that faced to the north. The direction the cavity faced was associated with the number of offspring per nest. The southwest-facing cavities had fewer offspring than nests on the northeast side. Our study indicates that the nesting box acts as a microclimate, with temperature varying by position and direction of the cavity. Variation in cavity temperature affected where females chose to nest, but not their reproductive investment.

scholarly journals Male-Biased Offspring Sex Ratio in the House Wren

The Condor ◽  
2002 ◽  
Vol 104 (4) ◽  
pp. 881-885
Author(s):  
Shannon M. Janota ◽  
Sheryl Swartz Soukup ◽  
Charles F. Thompson
Keyword(s):  
Sex Ratio ◽  
Breeding Season ◽  
Good Condition ◽  
Reproductive Value ◽  
Troglodytes Aedon ◽  
Offspring Sex Ratio ◽  
House Wren ◽  
House Wrens ◽  
Offspring Sex ◽  
Sex Ratio Adjustment

AbstractThe sex-ratio adjustment hypothesis predicts that females should modify offspring sex ratios according to the potential reproductive success of their offspring under existing ecological conditions. We tested this hypothesis in the polygynous, sexually size-monomorphic House Wren (Troglodytes aedon). Typically, nestling House Wrens that hatch in the first half of the three-month breeding season are heavier and have higher rates of survival and recruitment than those that hatch in the second half of the season. Therefore, the sex-ratio adjustment hypothesis predicts that early broods should be more male biased than later broods, because males in good condition have higher reproductive value than females. As conditions deteriorate, broods should become less male biased because female offspring have higher reproductive value than males in poor condition. Contrary to expectation, there was no seasonal decrease in offspring condition, and the sex ratio of broods was consistently male biased throughout the breeding season. We conclude that the results are consistent with the sex-ratio adjustment hypothesis, because in the year of this study female House Wrens were able to produce offspring in similar (and presumably good) condition throughout the breeding season; therefore, they continued to produce broods that were significantly male biased.Sesgo hacia Machos en el Cociente de Sexos de la Prole en Troglodytes aedonResumen. La hipótesis sobre el ajuste del cociente de sexos predice que las hembras deberían modificar el cociente de sexos de la prole en relación al éxito potencial reproductivo de la prole bajo las condiciones ecológicas existentes. Evaluamos esta hipótesis en Troglodytes aedon, especie polígina y sin diferencias sexuales de tamaño. Típicamente, los pichones de T. aedon que eclosionan en la primera mitad de la estación reproductiva (que dura tres meses) son más pesados y presentan tasas de supervivencia y reclutamiento más altas que aquellos que eclosionan en la segunda mitad de la estación. De este modo, la hipótesis sobre el ajuste del cociente de sexos predice que las camadas tempranas deberían estar más sesgadas hacia los machos que las camadas más tardías, ya que los machos en buena condición tienen un valor reproductivo más alto que las hembras. A medida que la condición se deteriora, las camadas deberían estar menos sesgadas hacia los machos debido a que los vástagos de sexo femenino tienen un valor reproductivo más alto que los machos en mala condición. Contrariamente a lo esperado, no hubo una disminución estacional en la condición de la prole, y el cociente de sexos de las camadas estuvo consistentemente sesgado hacia los machos a lo largo de la estación de cría. Concluimos que los resultados son consistentes con la hipótesis sobre el ajuste del cociente de sexos, ya que durante el año de este estudio las hembras de T. aedon fueron capaces de producir proles en condiciones similares (y presumiblemente buenas) a lo largo de la estación de cría. De este modo, las hembras continuaron produciendo camadas que estuvieron significativamente sesgadas hacia los machos.

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