CONSEQUENCES OF EGG SIZE FOR OFFSPRING SURVIVAL: A CROSS-FOSTERING EXPERIMENT IN RUDDY DUCKS (OXYURA JAMAICENSIS)

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 384 ◽  
Author(s):  
Jeffrey T. Pelayo ◽  
Robert G. Clark
Keyword(s):  
Egg Size ◽  
Offspring Survival ◽  
Ruddy Ducks ◽  
Cross Fostering ◽  
Oxyura Jamaicensis

scholarly journals Consequences of Egg Size for Offspring Survival: A Cross-Fostering Experiment in Ruddy Ducks (Oxyura Jamaicensis)

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 384-393
Author(s):  
Jeffrey T. Pelayo ◽  
Robert G. Clark
Keyword(s):  
Egg Size ◽  
Hatching Date ◽  
Offspring Survival ◽  
Maternal Influences ◽  
Size Dependent ◽  
Duck Species ◽  
In The Wild ◽  
Ruddy Ducks ◽  
Cross Fostering ◽  
Oxyura Jamaicensis

Abstract In birds, large egg size often enhances subsequent offspring survival, but most previous studies have been unable to separate effects of egg size from other maternal influences. Therefore, we first evaluated variance components of egg size both within and among individual female Ruddy Ducks (Oxyura jamaicensis), and then tested for egg-size-dependent survival of ducklings in the wild by switching complete broods among females. Forty broods consisting of 244 individually color-marked, day-old ducklings of known egg size were given to foster mothers, and survival was monitored to one month. Analysis of mark–resighting data showed that offspring survival was best modeled to include effects of egg size and hatching date; survival probability increased with egg size, but declined with advancing hatching date. Duckling body mass, body size, and body condition measured at hatching were positively correlated with egg size. Unlike most other duck species, and for reasons that are speculative, egg sizes varied within clutches nearly as much as they did among clutches. Selective mortality of small egg phenotypes during the first weeks after hatching likely is the result of smaller duckling size and reduced energy reserves, characteristics that must be particularly unfavorable in adverse environments.

Intraclutch egg-size variation and offspring survival in the Kentish Plover Charadrius alexandrinus

Ibis ◽  
2001 ◽  
Vol 143 (1) ◽  
pp. 17-23 ◽  
Author(s):  
JUAN A. AMAT ◽  
ROSENDO M. FRAGA ◽  
GONZALO M. ARROYO
Keyword(s):  
Egg Size ◽  
Size Variation ◽  
Offspring Survival ◽  
Charadrius Alexandrinus ◽  
Kentish Plover

Overcoming environmental and morphological constraints: egg size and pelvic kinesis in the smallest tortoise, Homopus signatus

2005 ◽  
Vol 83 (10) ◽  
pp. 1343-1352 ◽  
Author(s):  
M D Hofmeyr ◽  
B T Henen ◽  
V J.T Loehr
Keyword(s):  
Body Size ◽  
Southern Africa ◽  
Egg Size ◽  
Reproductive Output ◽  
Selective Advantage ◽  
Arid Environment ◽  
Harsh Environment ◽  
Offspring Survival ◽  
Aridity Gradient ◽  
East West

The small tortoises of southern Africa include the only testudinid taxa that produce single-egg clutches. This group includes the world's smallest tortoise, Homopus signatus (Gmelin, 1789), which inhabits a harsh, arid environment. Climate and body size may influence reproductive output, so we hypothesized that the east–west aridity gradient in southern Africa affects egg and clutch size of the small indigenous tortoises, and that the morphology of H. signatus constrains egg size, preventing the formation of optimal eggs. Here we show that aridity and unpredictable rainfall determine which of these tortoise taxa produce single-egg clutches. Taxa in less predictable environments produce larger eggs relative to body size than do taxa in more predictable environments. Homopus signatus produces the largest egg relative to body size, probably to enhance offspring survival in its harsh environment. Body size, pelvic aperture size, and the narrow anal gap of H. signatus appear to constrain egg size. Despite these constraints, females produce rigid-shelled eggs larger than the pelvic canal and use pelvic kinesis to pass eggs at oviposition; both features are unknown in other chelonians and emphasize the selective advantage of large eggs to H. signatus.

scholarly journals Variation in Size, Composition, and Quality of Ruddy Duck Eggs and Ducklings

The Condor ◽  
2002 ◽  
Vol 104 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Jeffrey T. Pelayo ◽  
Robert G. Clark
Keyword(s):  
Body Size ◽  
Egg Size ◽  
Size Composition ◽  
Egg Mass ◽  
Direct Proportion ◽  
Female Body Size ◽  
Ruddy Duck ◽  
Better Than ◽  
Oxyura Jamaicensis

AbstractTo evaluate why ducklings hatching from large eggs generally survive better than ducklings from small eggs, we quantified egg-size-related variation in composition and quality of eggs and ducklings of wild Ruddy Ducks (Oxyura jamaicensis). Fresh egg mass averaged 74.1 ± 4.3 g (SD), but ranged from 60.5 to 83.8 g. Despite remarkably large egg size relative to adult female body size, and a 1.4-fold difference in mass between the smallest and largest eggs, most egg constituents increased in direct proportion to fresh egg mass, with bigger eggs producing heavier and larger ducklings. However, large ducklings had proportionately larger yolk sac stores than did small ducklings. Thus, large ducklings also had greater total lipid reserves, an advantage that could enable them to survive better than small ducklings during the first few days after hatching.Variación en el Tamaño, Composición y Calidad de los Huevos y Polluelos de Oxyura jamaicensisResumen. Para evaluar por qué los polluelos que eclosionan de huevos grandes sobreviven mejor que polluelos provenientes de huevos pequeños, cuantificamos la variación en la composición y calidad de huevos y polluelos en relación al tamaño del huevo en Oxyura jamaicensis. La masa fresca de los huevos promedió 74.1 ± 4.3 g (DE), pero varió entre 60.5 y 83.8 g. A pesar del gran tamaño de los huevos en relación al tamaño corporal de la hembra, y de una diferencia de 1.4 veces en la masa entre el huevo más pequeño y él más grande, la mayoría de los componentes del huevo aumentaron en proporción directa con la masa fresca del huevo. Huevos más grandes produjeron polluelos más grandes y pesados. Sin embargo, polluelos grandes presentaron relativamente mayores reservas en el saco vitelino que polluelos pequeños. Por lo tanto, los polluelos grandes también presentaron una mayor reserva total de lípidos, ventaja que podría permitirles sobrevivir mejor que a los polluelos más pequeños durante los primeros días luego de la eclosión.

scholarly journals Divergent coevolutionary trajectories in parent–offspring interactions and discrimination against brood parasites revealed by interspecific cross-fostering

2018 ◽  
Vol 5 (6) ◽  
pp. 180189 ◽  
Author(s):  
Alexandra Capodeanu-Nägler ◽  
Elena Ruiz de la Torre ◽  
Anne-Katrin Eggert ◽  
Scott K. Sakaluk ◽  
Sandra Steiger
Keyword(s):  
Interspecific Cross ◽  
Offspring Survival ◽  
Burying Beetles ◽  
Differential Survival ◽  
Closely Related Species ◽  
Brood Parasites ◽  
Nicrophorus Vespilloides ◽  
Nicrophorus Orbicollis ◽  
Direct Recognition ◽  
Cross Fostering

In animal families, parents are expected to adapt to their offspring's traits, and offspring, in turn, are expected to adapt to the environment circumscribed by their parents. However, whether such coevolutionary trajectories differ between closely related species is poorly understood. Here, we employ interspecific cross-fostering in three species of burying beetles, Nicrophorus orbicollis , Nicrophorus pustulatus and Nicrophorus vespilloides , to test for divergent co-adaptation among species with different degrees of offspring dependency on parental care, and to test whether they are able to discriminate against interspecific parasites. We found that offspring survival was always higher when offspring were reared by conspecific rather than heterospecific parents. In the case of N. orbicollis raising N. pustulatus , none of the larvae survived. Overall, these results indicate that parent and offspring traits have diverged between species, and that the differential survival of conspecific and heterospecific larvae is because of improper matching of co-adapted traits, or, in the case of N. orbicollis with larval N. pustulatus , because of selection on parents to recognize and destroy interspecific brood parasites. We suggest that burying beetles experiencing a high risk of brood parasitism have evolved direct recognition mechanisms that enable them to selectively kill larvae of potential brood parasites.

scholarly journals A brood parasite selects for its own egg traits

2013 ◽  
Vol 9 (5) ◽  
pp. 20130573 ◽  
Author(s):  
Claire N. Spottiswoode
Keyword(s):  
Host Species ◽  
Egg Size ◽  
Interference Competition ◽  
Offspring Survival ◽  
Brood Parasite ◽  
Host Nest ◽  
Size And Shape ◽  
Parasitic Female ◽  
Egg Traits

Many brood parasitic birds lay eggs that mimic their hosts' eggs in appearance. This typically arises from selection from discriminating hosts that reject eggs which differ from their own. However, selection on parasitic eggs may also arise from parasites themselves, because it should pay a laying parasitic female to detect and destroy another parasitic egg previously laid in the same host nest by a different female. In this study, I experimentally test the source of selection on greater honeyguide ( Indicator indicator ) egg size and shape, which is correlated with that of its several host species, all of which breed in dark holes. Its commonest host species did not discriminate against experimental eggs that differed from their own in size and shape, but laying female honeyguides preferentially punctured experimental eggs more than host or control eggs. This should improve offspring survival given that multiple parasitism by this species is common, and that honeyguide chicks kill all other nest occupants. Hence, selection on egg size in greater honeyguides parasitizing bee-eaters appears to be imposed not by host defences but by interference competition among parasites themselves.

scholarly journals Juvenile exposure to predator cues induces a larger egg size in fish

2011 ◽  
Vol 279 (1731) ◽  
pp. 1241-1248 ◽  
Author(s):  
Francisca H. I. D. Segers ◽  
Barbara Taborsky
Keyword(s):  
Body Size ◽  
Predation Risk ◽  
Egg Size ◽  
Growth Trajectories ◽  
Egg Mass ◽  
Offspring Survival ◽  
Predator Cues ◽  
Female Body Size ◽  
Natural Predator ◽  
Perceived Predation Risk

When females anticipate a hazardous environment for their offspring, they can increase offspring survival by producing larger young. Early environmental experience determines egg size in different animal taxa. We predicted that a higher perceived predation risk by juveniles would cause an increase in the sizes of eggs that they produce as adults. To test this, we exposed juveniles of the mouthbrooding cichlid Eretmodus cyanostictus in a split-brood experiment either to cues of a natural predator or to a control situation. After maturation, females that had been confronted with predators produced heavier eggs, whereas clutch size itself was not affected by the treatment. This effect cannot be explained by a differential female body size because the predator treatment did not influence growth trajectories. The observed increase of egg mass is likely to be adaptive, as heavier eggs gave rise to larger young and in fish, juvenile predation risk drops sharply with increasing body size. This study provides the first evidence that predator cues perceived by females early in life positively affect egg mass, suggesting that these cues allow her to predict the predation risk for her offspring.

scholarly journals Intralocus conflicts associated with a supergene

2021 ◽  
Author(s):  
Lina Giraldo-Deck ◽  
Jasmine Loveland ◽  
Wolfgang Goymann ◽  
Barbara Tschirren ◽  
Terry Burke ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Reproductive Performance ◽  
Egg Size ◽  
Reproductive Output ◽  
Balancing Selection ◽  
Male Mating ◽  
Captive Population ◽  
Offspring Survival ◽  
Chromosomal Inversions ◽  
Negative Frequency Dependent Selection

Abstract Chromosomal inversions frequently underlie major phenotypic variation maintained by divergent selection within and between sexes. Here we examine whether and how intralocus conflicts contribute to balancing selection stabilizing an autosomal inversion polymorphism in the ruff Calidris pugnax. In this lekking shorebird, three male mating morphs (Independents, Satellites and Faeders) are associated with an inversion-based supergene. We show that in a captive population, Faeder females, who are smaller and whose inversion haplotype has not undergone recombination, have lower average reproductive success in terms of laying rate, egg size and offspring survival than Independent females, who lack the inversion. Satellite females, who carry a recombined inversion haplotype and have intermediate body size, more closely resemble Independent than Faeder females in reproductive performance. We inferred that the lower reproductive output of Faeder females is primarily balanced by higher than average reproductive success of individual Faeder males, driven by negative frequency-dependent selection. These findings suggest that intralocus conflicts may play a major role in the evolution and maintenance of supergene variants.

scholarly journals Dietary ARA Improves COX Activity in Broodstock and Offspring Survival Fitness of a Model Organism (Medaka Oryzias latipes)

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2174
Author(s):  
Agata Kowalska ◽  
Maciej Kamaszewski ◽  
Marta Czarnowska-Kujawska ◽  
Piotr Podlasz ◽  
Radosław K. Kowalski
Keyword(s):  
Sperm Motility ◽  
Egg Size ◽  
Model Organism ◽  
Dietary Exposure ◽  
Hatching Rate ◽  
Offspring Survival ◽  
Feeding Trial ◽  
Total Fatty Acids ◽  
Survival And Growth ◽  
Motility Parameters

A 3-week feeding trial was conducted in medaka broodstock (age five months) to examine the effect of dietary arachidonic acid (ARA) level (range: 4–23 mg g−1 of total fatty acids (TFAs)) on fertility, cyclooxygenase (COX) activity, egg size, sperm motility parameters, hatching rate and weight of hatch, survival and growth of larvae. After spawn induction and dietary exposure to 4 mg ARA g−1 TFA, broodstock were fed a diet containing ARA in the amounts: 4 (continued, as control), 5, 14 and 23 mg g−1 TFA. COX1 activity in the liver and the number of COX2-positive cells in the ovaries was increased in females fed the diets containing the two highest amounts of ARA. The highest sperm motility parameters were observed in males fed a diet containing 23 mg ARA g−1 TFA. The hatchability rate and bodyweight of hatchlings were higher in the group obtained from broodstock fed a diet containing 23 mg ARA g−1 TFA (79% and 0.66 mg fish−1, respectively) compared with 4 mg ARA g−1 TFA (50% and 0.40 mg fish−1). The average mortality of offspring obtained from this group at 7 days post hatching was significantly higher than that of all other groups.

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