Variations in size and growth of Great skua Catharacta skua chicks in relation to adult age, hatching date, egg volume, brood size and hatching sequence

2009 ◽  
Vol 199 (1) ◽  
pp. 101-116 ◽  
Author(s):  
R. W. Furness
Keyword(s):  
Brood Size ◽  
Hatching Date ◽  
Egg Volume ◽  
Adult Age

Life cycles of the rhizocephalan Boschmaella japonica Deichmann & Høeg, 1990 (Cirripedia: Chthamalophilidae) and its host barnacle Chthamalus challengeri Hoek, 1883 (Cirripedia: Chthamalidae)

2020 ◽  
Vol 40 (6) ◽  
pp. 825-832 ◽  
Author(s):  
Miku Yabuta ◽  
Jens T Høeg ◽  
Shigeyuki Yamato ◽  
Yoichi Yusa
Keyword(s):  
Life Cycle ◽  
Brood Size ◽  
Life Cycles ◽  
The Body ◽  
Egg Volume ◽  
Size Number ◽  
Rhizocephalan Barnacles ◽  
Western Japan ◽  
Upper Intertidal ◽  
Chthamalus Challengeri

Abstract Although parasitic castration is widespread among rhizocephalan barnacles, Boschmaella japonica Deichmann & Høeg, 1990 does not completely sterilise the host barnacle Chthamalus challengeri Hoek, 1883. As little information is available on the relationships with the host in “barnacle-infesting parasitic barnacles” (family Chthamalophilidae), we studied the life cycles of both B. japonica and C. challengeri and the effects of the parasite on the host reproduction. Specimens of C. challengeri were collected from an upper intertidal shore at Shirahama, Wakayama, western Japan from April 2017 to September 2018 at 1–3 mo intervals. We recorded the body size, number of eggs, egg volume, and the presence of the parasite for each host. Moreover, settlement and growth of C. challengeri were followed in two fixed quadrats. Chthamalus challengeri brooded from February to June. The prevalence of B. japonica was high (often exceeded 10%) from April to July, and was rarely observed from September to next spring. The life cycle of the parasite matched well with that of the host. The parasite reduced the host’s brooding rate and brood size, to the extent that no hosts brooded in 2018.

scholarly journals Effects of Hatching Date and Egg Size on Growth, Recruitment, and Adult Size of Lesser Scaup

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 930-935 ◽  
Author(s):  
Russell D. Dawson ◽  
Robert G. Clark
Keyword(s):  
Selective Advantage ◽  
Breeding Population ◽  
Adult Size ◽  
Hatching Date ◽  
Egg Volume ◽  
Brood Rearing ◽  
Aythya Affinis ◽  
Lesser Scaup ◽  
Local Breeding ◽  
Nutrient Reserves

AbstractEvidence suggests that birds breeding early in the season or laying larger eggs are at a selective advantage because quality and survival of their offspring are higher. We tested whether wild Lesser Scaup (Aythya affinis) hatching early in the season or from larger eggs had enhanced growth as ducklings and larger size or higher probability of recruiting to the local breeding population in years after hatching. After correcting for age at capture, body mass, head length, and culmen of ducklings were inversely related to hatching date, but were unrelated to egg volume. As adults, late-hatched birds had shorter wing lengths (second-year birds only) and tended to have smaller head lengths (all after-hatch year birds) than early hatching birds. We suggest that later-hatching birds are smaller due to increased competition for food during brood rearing. Recruitment probability increased as natal egg volume increased and decreased among birds with later natal hatching dates. We speculate these results are due to higher mortality of ducklings hatched from small eggs, and because early-hatched birds have more time to acquire nutrient reserves that would reduce vulnerability to costs of migration.

scholarly journals Parent–offspring conflict and transition to crèche phase in Chinstrap Penguins (Pygoscelis antarctica)

Polar Biology ◽  
2021 ◽  
Vol 44 (10) ◽  
pp. 1961-1966
Author(s):  
Virginia Morandini ◽  
Javier Viñuela ◽  
Josabel Belliure ◽  
Miguel Ferrer
Keyword(s):  
Parental Investment ◽  
Brood Size ◽  
Parental Behavior ◽  
Conflict Theory ◽  
Hatching Date ◽  
Nest Location ◽  
Decision To Leave ◽  
Pygoscelis Antarctica ◽  
Parental Aggression ◽  
Short Time

AbstractParent–offspring conflict theory predicts that offspring seek to prolong the parental care period, while parents strive to shorten it as much as possible. Transition to the crèche phase in penguins involves changes in the dynamic of parental investment in chicks, and thus may be modulated by interests that benefit parent or offspring. We explored parent–offspring interactions in the Chinstrap Penguin (Pygoscelis antarctica) to understand the influence such interactions would have on transition to crèche phase. We studied the effect of hatching date, nestling age, brood size, and nest location on parent–offspring interactions and the length of the guard phase. All behavioral variables related to nestling demands for parental investment increased as well as parental aggression towards their chicks, with increased nestling age. Brood size showed significant effects on both nestling and parental behavior. Hatching date was negatively correlated with the age at crèche. Consequently, the decision to leave the chicks unguarded seemed to be more based on the condition of adults rather than of the chicks. Given the short time available for breeding in Antarctica and that penguins are long-lived birds with several opportunities to breed, there may be conflicting selective factors between investment in feeding chicks versus extending the period of resource acquisition and storage prior to moult.

Effect of Experimentally Altered Brood Size on Frequency and Timing of Second Clutches in the Great Tit

The Auk ◽  
1987 ◽  
Vol 104 (4) ◽  
pp. 700-706 ◽  
Author(s):  
Henrik G. Smith ◽  
Hans Källander ◽  
Jan-Åke Nilsson
Keyword(s):  
Brood Size ◽  
Parus Major ◽  
Reproductive Development ◽  
Great Tit ◽  
Lower Probability ◽  
Hatching Date ◽  
Fledgling Survival ◽  
First Clutch ◽  
Second Clutch ◽  
Food Depletion

Abstract Brood size in the Great Tit (Parus major) was manipulated (increased, decreased, or unchanged) when nestlings were 5 days old. Both the frequency of second clutches and the interbrood interval were affected. The number of nestlings and hatching date, but not nestling and female mass, differed between first broods followed and not followed by second clutches. Hatching date and the number of nestlings in the first brood explained most of the variation in interbrood interval, whereas female mass did not contribute. Feeding first-brood nestlings and fledglings is an energy-demanding process, and the female may have to allocate resources to brood-feeding at the expense of reproductive development. Furthermore, a larger brood requires a longer period of feeding than a smaller brood. These circumstances probably explain why the size of the first brood affects the timing of the second clutch. Female condition and food depletion of the territory do not seem to be important. Because late second clutches have a lower probability of fledgling survival than do earlier ones-and consequently are of lower value from the female's standpoint-a large first clutch may delay laying to the point that a second clutch is not worthwhile. We conclude that a female's decision whether to lay a second clutch is a strategic one based on the value of the second clutch; a female that "decides" to lay a second clutch starts as quickly as possible.

Reproductive ecology of the velvet swimming crab, Necora puber (Brachyura: Portunidae), at Plymouth

1993 ◽  
Vol 73 (2) ◽  
pp. 379-389 ◽  
Author(s):  
C. P. Norman ◽  
M. B. Jones
Keyword(s):  
Sex Ratio ◽  
Embryonic Development ◽  
Brood Size ◽  
Swimming Crab ◽  
Egg Volume ◽  
The United Kingdom ◽  
South West ◽  
Near Shore ◽  
Brood Number ◽  
South West England

Monthly samples of intertidal and near-shore Necora puber were collected over two years from a commercially unfished area around Plymouth (south-west England). A clear reproductive cycle, consistent between the two years, was observed, and relatively high numbers of ovigerous females were found from January to June. Zoeal release was estimated to occur from April to June. Ovigerous females had developing ovaries, indicating that sequential broods occur. During embryonic development, egg volume increased by 109%, and egg loss was significant, accounting for between 14 and 18.5% of initial brood number. Females suffering limb loss showed a further reduced brood size compared to females with a full limb complement. The sex ratio of immature crabs was 1:1, whereas the ratio for mature crabs was biased to males (1.46:1). Two sperm plugs were observed in 90% of early postmoult mature females, but 10% had only one or no plug intact, suggesting their failure to mate successfully. These results are reviewed in relation to the biogeography of N. puber and with reference to the developing fishery in the United Kingdom.

Attachment and Field Dependence: Individual Differences in Information Processing

2004 ◽  
Vol 9 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Patrizia Vermigli ◽  
Alessandro Toni
Keyword(s):  
Information Processing ◽  
Individual Differences ◽  
Field Dependence ◽  
Attachment Styles ◽  
Close Relationships ◽  
Adult Age ◽  
Males And Females ◽  
Figure Test ◽  
The Relationship ◽  
Measure Field

The present research analyzes the relationship between attachment styles at an adult age and field dependence in order to identify possible individual differences in information processing. The “Experience in Close Relationships” test of Brennan et al. was administered to a sample of 380 individuals (160 males, 220 females), while a subsample of 122 subjects was given the Embedded Figure Test to measure field dependence. Confirming the starting hypothesis, the results have shown that individuals with different attachment styles have a different way of perceiving the figure against the background. Ambivalent and avoidant individuals lie at the two extremes of the same dimension while secure individuals occupy the central part. Significant differences also emerged between males and females.

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