The effect of female body condition on egg laying in Lesser black-backed gulls Larus fuscus

1. Isolated unmated female body-lice were worn in pillboxes between the skin and the clothes. They were kept constantly on the body but, by a simple device, groups of ten were permitted feeding periods of different length. These groups were fed for 4, 8, 12, 16, 20 and 24 hr. per day respectively. Another group of ten were never allowed to feed after the last moult.2. Some of the figures for egg yield were high. Lice in the 24 hr. group were able to maintain a rate of ten eggs per day for 4−5 days at a time.3. No significant difference in longevity or rate of egg-laying was found to exist between the 12, 16, 20 and 24 hr. groups nor between the 4 and 8 hr. groups but a pronounced and significant difference exists between the 8 and 12 hr. groups. Below 12 hr. there is a sharp fall in longevity and rate of egg production. The unfed group all died, without laying, on the third day.4. The rate of laying as shown by the mode increases progressively with increase in time allowed daily for feeding.5. With regard to the mean eggs per louse the position is less clear. It is felt that the 24 hr. group may differ significantly from the 12, 16 and 20 hr. groups but this is uncertain.

Download Full-text

Nutrient Reserves of Lesser Scaup (Aythya Affinis) During Spring Migration in the Mississippi Flyway: A Test of the Spring Condition Hypothesis

The Auk ◽

10.1093/auk/121.3.917 ◽

2004 ◽

Vol 121 (3) ◽

pp. 917-929 ◽

Cited By ~ 9

Author(s):

Michael J. Anteau ◽

Alan D. Afton

Keyword(s):

Reproductive Success ◽

Body Mass ◽

Body Condition ◽

Female Body ◽

Population Decline ◽

Spring Migration ◽

Aythya Affinis ◽

Lesser Scaup ◽

Nutrient Reserves ◽

Mineral Reserves

AbstractThe continental scaup population (Lesser [Aythya affinis] and Greater [A. marila] combined) has declined markedly since 1978. One hypothesis for the population decline states that reproductive success has decreased because female scaup are arriving on breeding areas in poorer body condition than they did historically (i.e. spring condition hypothesis). We tested one aspect of that hypothesis by comparing body mass and nutrient reserves (lipid, protein, and mineral) of Lesser Scaup at four locations (Louisiana, Illinois, Minnesota, and Manitoba) between the 1980s and 2000s. We found that mean body mass and lipid and mineral reserves of females were 80.0, 52.5, and 3.0 g higher, respectively, in the 2000s than in the 1980s in Louisiana; similarly, body mass and lipid and mineral reserves of males were 108.8, 72.5, and 2.5 g higher, respectively. In Illinois, mean body mass and lipid reserves of females were 88.6 and 56.5 g higher, respectively, in the 2000s than in the 1980s; similarly, body mass and lipid and mineral reserves of males were 80.6, 76.0, and 2.7 g higher, respectively. Mean body mass of females were 58.5 and 58.9 g lower in the 2000s than in the 1980s in Minnesota and Manitoba, respectively; mean body mass of males, similarly, were 40.7 g lower in Minnesota. Mean lipid reserves of females in the 2000s were 28.8 and 27.8 g lower than those in the 1980s in Minnesota and Manitoba, respectively. Mean mineral reserves of females in the 2000s were 3.2 g lower than those in the 1980s in Manitoba. Consequently, females arriving to breed in Manitoba in the 2000s had accumulated lipid reserves for 4.1 fewer eggs and mineral reserves for 0.8 fewer eggs than those arriving to breed there in the 1980s. Accordingly, our results are consistent with the spring condition hypothesis and suggest that female body condition has declined, as reflected by decreases in body mass, lipids, and mineral reserves that could cause reductions in reproductive success and ultimately a population decline.

Download Full-text

Decision letter for "Ambient temperature and female body condition are related to night incubation behavior in wood ducks ( Aix sponsa )"

10.1111/jav.02379/v2/decision1 ◽

2020 ◽

Keyword(s):

Ambient Temperature ◽

Body Condition ◽

Female Body ◽

Aix Sponsa ◽

Incubation Behavior ◽

Wood Ducks

Download Full-text

Review for "Ambient temperature and female body condition are related to night incubation behavior in wood ducks ( Aix sponsa )"

10.1111/jav.02379/v1/review1 ◽

2019 ◽

Author(s):

Denis Deeming

Keyword(s):

Ambient Temperature ◽

Body Condition ◽

Female Body ◽

Aix Sponsa ◽

Incubation Behavior ◽

Wood Ducks

Download Full-text

Effects of Incubation Conditions and Offspring Sex on Embryonic Development and Survival in the Zebra Finch (Taeniopygia Guttata)

The Auk ◽

10.1093/auk/122.4.1239 ◽

2005 ◽

Vol 122 (4) ◽

pp. 1239-1248 ◽

Cited By ~ 1

Author(s):

Helen E. Gorman ◽

Kate J. Orr ◽

Aileen Adam ◽

Ruedi G. Nager

Keyword(s):

Embryonic Development ◽

Body Condition ◽

Egg Quality ◽

Good Condition ◽

Taeniopygia Guttata ◽

Egg Laying ◽

Male And Female ◽

Embryo Mortality ◽

Offspring Fitness ◽

Offspring Sex

AbstractSuboptimal conditions during embryonic development can affect offspring fitness. Both egg quality and incubation behavior can affect hatching success, hatching mass, and subsequent offspring performance. These effects may differ between male and female offspring. We manipulated the prebreeding body condition of Zebra Finches (Taeniopygia guttata), using diets of different protein content. To separate possible effects on egg quality of parental body condition and incubation conditions, we did a cross-fostering experiment. We analyzed embryo survival and hatching mass with respect to body condition of the egg-laying parent, body condition of the incubating foster parent, and offspring sex. Embryos were not affected by the condition of the egg-laying parent. Eggs incubated by parents in better condition suffered less embryo mortality than those incubated by parents in poorer condition, but only when overall embryo mortality was low. Hatching mass was also affected by the incubating foster parent’s body condition. And hatchlings incubated by parents in good condition were heavier than those incubated by parents in poor condition. Female hatchlings from late-laid eggs were heavier, in comparison with the size of the egg from which they hatched, than female hatchlings from earlier-laid eggs. No such effect was found for males. Therefore, male and female embryos may differ in their sensitivity to suboptimal conditions during embryonic development. These results suggest that parental body condition during incubation can affect offspring fitness.Efectos de las Condiciones de Incubación y el Sexo de las Crías sobre el Desarrollo Embrional y la Supervivencia en Taeniopygia guttata

Download Full-text

Factors affecting brood abandonment in gadwalls (Anas strepera)

Canadian Journal of Zoology ◽

10.1139/z99-216 ◽

2000 ◽

Vol 78 (2) ◽

pp. 327-331 ◽

Cited By ~ 4

Author(s):

Michel Gendron ◽

Robert G Clark

Keyword(s):

Body Condition ◽

Brood Size ◽

Female Body ◽

Confounding Factor ◽

Factors Affecting ◽

Proximate Factors ◽

Anas Strepera ◽

Brood Desertion ◽

Brood Success

Brood desertion by radio-equipped female gadwalls (Anas strepera) was examined to test three hypotheses regarding proximate factors responsible for post hatch brood abandonment in waterfowl. Gadwall broods with the greatest duckling mortality, independent of brood size, were more likely to be abandoned, providing support for the "brood-success" hypothesis. Our results do not support the "brood-size" hypothesis, as the size of broods immediately prior to female abandonment was no smaller than the size of broods not abandoned. Although brood fate was not related to female body condition, the "salvage-strategy" hypothesis could not be rejected, because experience was a confounding factor and could not be sampled adequately; younger, possibly less-experienced females were more likely to abandon their broods than older females. Further studies, preferably involving experimental manipulations, are needed to adequately address the full array of hypotheses.

Download Full-text