scholarly journals Effects of Temperature Variability on Egg Mass and Clutch Size in Great Tits

The Condor ◽  
2005 ◽  
Vol 107 (3) ◽  
pp. 710-714 ◽  
Author(s):  
Christopher J. Pendlebury ◽  
David M. Bryant
Keyword(s):  
Clutch Size ◽  
Climate Changes ◽  
Wild Population ◽  
Parus Major ◽  
Egg Laying ◽  
Egg Mass ◽  
Ambient Temperatures ◽  
Mean Temperature ◽  
Effects Of Temperature ◽  
Thermal Variability

Abstract Models of climate change generally predict rising mean global temperatures combined with greater variability in some regions. While relationships between mean temperature and several reproductive parameters are well documented, the effect of day-to-day variation in ambient temperature has received little attention. In our study, temperature variation had no significant effects on clutch size in a wild population of Great Tits (Parus major). In contrast, egg mass tended to be smaller when ambient temperatures during the week prior to laying were more variable. We suggest that variable temperatures may be disadvantageous to an egg-laying bird. Thermal variability should therefore be considered as a discrete factor, distinct from mean temperature, when assessing the consequences of climate changes for breeding birds. Efectos de la Variabilidad de la Temperatura sobre la Masa del Huevo y el Tamaño de la Nidada en Parus major Resumen. Los modelos de cambio climático generalmente predicen un aumento en la temperatura media global, junto con una mayor variabilidad en algunas regiones. Mientras que la relación entre la temperatura media y varios parámetros reproductivos está bien documentada, el efecto de la variación de la temperatura ambiente de un día a otro ha recibido poca atención. La variación en la temperatura no tuvo efectos significativos en nuestro estudio del tamaño de la nidada en una población silvestre de Parus major. En contraste, la masa del huevo tendió a ser menor cuando las temperaturas ambiente durante la semana previa a la puesta fueron más variables. Sugerimos que las temperaturas variables podrían ser desventajosas para un ave que está poniendo huevos. La variación térmica debería por lo tanto ser considerada como un factor discreto, diferente de la temperatura media, cuando se evalúan las consecuencias del cambio climático para las aves reproductivas.

scholarly journals Reproductive suppression in female cooperatively breeding cichlids

2008 ◽  
Vol 4 (6) ◽  
pp. 606-609 ◽  
Author(s):  
Dik Heg
Keyword(s):  
Clutch Size ◽  
Group Living ◽  
Egg Laying ◽  
Alloparental Care ◽  
Large Female ◽  
Egg Mass ◽  
Small Female ◽  
Reproductive Suppression ◽  
Cooperatively Breeding ◽  
Female Subordinate

Suppression by dominants of female subordinate reproduction has been found in many vertebrate social groups, but has rarely been shown experimentally. Here experimental evidence is provided for reproductive suppression in the group-living Lake Tanganyika cichlid Neolamprologus pulcher . Within groups of three unrelated females, suppression was due to medium- and small-sized females laying less frequently compared with large females, and compared with medium females in control pairs. Clutch size and average egg mass of all females depended on body size, but not on rank. In a second step, a large female was removed from the group and a very small female was added to keep the group size constant. The medium females immediately seized the dominant breeding position in the group and started to reproduce as frequently as control pairs, whereas clutch size and egg mass did not change. These results show that female subordinate cichlids are reproductively capable, but apparently suppressed with respect to egg laying. Nevertheless, some reproduction is tolerated, possibly to ensure continued alloparental care by subordinate females.

Annual variation in common eider egg size: effects of temperature, clutch size, laying date, and laying sequence

1995 ◽  
Vol 73 (9) ◽  
pp. 1579-1587 ◽  
Author(s):  
Gregory J. Robertson
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Annual Variation ◽  
Size Variation ◽  
Egg Laying ◽  
Laying Date ◽  
Somateria Mollissima ◽  
Ambient Temperatures ◽  
Common Eiders ◽  
N 93

Annual variation in volumes of eggs laid by common eiders (Somateria mollissima sedentaria) nesting at La Pérouse Bay, Manitoba (58°43′N, 93°27′W), was studied over 3 years (1991–1993). Temperatures during the egg-laying period were higher in 1991 than in 1992 and 1993. However, the eiders began nesting in 1993 at the same time as in 1991, whereas in 1992 the eiders began laying approximately 2 weeks later. Eiders laid significantly smaller clutches in 1992 than in the other 2 years. Egg size did not correlate with clutch size or laying date in any year. However, eiders laid smaller eggs in 1992 and 1993 than in 1991. In five egg clutches, the pattern of intraclutch egg-size variation was different among years. The last laid eggs of five egg clutches were disproportionately smaller in 1992 and 1993 (cold years) than those laid in 1991. Minimum daily temperatures before the egg-laying period (during rapid yolk development) were positively correlated with egg size. However, this effect was not significant when year and egg sequence were controlled for. Egg-size variation was correlated with the overall ambient temperatures during the laying period, whereas annual clutch-size variation was correlated with laying date, suggesting that the proximate mechanisms affecting clutch and egg size are different.

scholarly journals Reproductive traits of the gray ratsnake Ptyas korros from three geographically distinct populations

2012 ◽  
Vol 58 (6) ◽  
pp. 820-827 ◽  
Author(s):  
Long-Hui Lin ◽  
Fei Mao ◽  
Ce Chen ◽  
Xiang Ji
Keyword(s):  
Clutch Size ◽  
Egg Size ◽  
Reproductive Output ◽  
Reproductive Traits ◽  
Egg Laying ◽  
Laying Date ◽  
Egg Mass ◽  
Size Number ◽  
Female Reproductive Traits ◽  
Clutch Mass

Abstract We collected gravid gray rat snakes Ptyas korros from three geographically distinct populations in China, Chenzhou (CZ), Jiangshan (JS) and Dinghai (DH), to study geographical variation in female reproductive traits. Egg-laying dates differed among the three populations such that at the most northern latitude egg-laying was latest, and earliest at the most southern lati-tutde. Clutch size, clutch mass, egg mass, egg shape, within clutch variability in egg sizes and relative clutch mass differed among the three populations, whereas post-oviposition body mass did not. Except for egg-laying date, none of the traits examined varied in a geographically continuous trend. CZ and DH females, although separated by a distance of approximately 1100 km as the crow flies, were similar in nearly all traits examined. JS females were distinguished from CZ and DH females by their higher fecundity (clutch size), greater reproductive output (clutch mass) and more rounded eggs. Our data do not validate the prediction that larger offspring should be produced in colder localities. The absence of an egg size-number trade-off in each of the three populations presumably suggests that P. korros is among species where eggs are well optimized for size within a population.

Genomic dissection of variation in clutch size and egg mass in a wild great tit (Parus major) population

2013 ◽  
Vol 22 (15) ◽  
pp. 3949-3962 ◽  
Author(s):  
Anna W. Santure ◽  
Isabelle De Cauwer ◽  
Matthew R. Robinson ◽  
Jocelyn Poissant ◽  
Ben C. Sheldon ◽  
...  
Keyword(s):  
Clutch Size ◽  
Parus Major ◽  
Great Tit ◽  
Egg Mass

scholarly journals Dietary carotenoid supplementation facilitates egg laying in a wild passerine

2019 ◽  
Author(s):  
Jorge García-Campa ◽  
Wendt Müller ◽  
Sonia González-Braojos ◽  
Emilio García-Juárez ◽  
Judith Morales
Keyword(s):  
Embryonic Development ◽  
Clutch Size ◽  
Egg Production ◽  
Egg Quality ◽  
Antioxidant Properties ◽  
Egg Laying ◽  
Egg Mass ◽  
Blue Tit ◽  
Trade Off ◽  
Dietary Carotenoid

During egg laying, female birds face a trade-off between self-maintenance and investment into current reproduction. Providing eggs with resources is energetically demanding, since in most species females lay one egg per day. However, the costs of egg laying not only relate to energetic requirements, but also depend on the availability of specific resources that are vital for egg production and embryonic development. One of these compounds are carotenoids, pigments with antioxidant properties and immuno-stimulatory functions, which are crucial during embryonic development. In this study, we explore how carotenoid availability alleviates this trade-off and facilitates egg laying in the blue tit. Blue tit females lay one egg per day and have the largest clutch size of all European passerines. We performed a lutein supplementation experiment, and measured potential consequences for egg laying capacity and egg quality. We found that lutein-supplemented females had less laying interruptions and thus completed their clutch faster than control females. No effects of treatment were found on the onset of egg laying or clutch size. Experimentally enhanced carotenoid availability did not elevate yolk carotenoid levels or egg mass, but negatively affected eggshell thickness. Our results provide hence evidence on the limiting role of carotenoids during egg laying, However, the benefits of laying faster following lutein supplementation were counterbalanced by a lower accumulation of calcium in the eggshell. Thus, even though single components may constrain egg laying, it is the combined availability of a range of different resources which ultimately determines egg quality and thus embryonic development.

scholarly journals Individual and Resource-Dependent Variation in Ability to Lay Supranormal Clutches in Response to Egg Removal

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 481-489
Author(s):  
Tony D. Williams ◽  
Melinda Miller
Keyword(s):  
Clutch Size ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Egg Laying ◽  
Interindividual Variation ◽  
Egg Mass ◽  
Systematic Change ◽  
High Quality ◽  
Quality Diet ◽  
Egg Removal

Abstract We investigated individual and resource-dependent variation in ability of female Zebra Finches (Taeniopygia guttata) to lay supranormal clutches in response to egg removal, and effect of continuous laying on (1) egg composition and (2) plasma yolk precursor levels. Egg removal significantly increased the number of eggs that individual females laid, but that response was diet-dependent: on a high-quality (egg-supplemented) diet, females laid 12.4 ± 1.0 more eggs compared with their pretreatment clutch size; whereas on the low-quality (seed-only) diet, females laid only 4.9 ± 1.2 more eggs. Removal clutch size (i.e. total number of eggs laid in response to egg removal) was positively correlated with pretreatment mean egg mass and clutch size on the low-quality diet, but not on the high-quality diet. That suggests that there is interindividual variation in egg-laying ability (“large-egg” females had a greater capacity to respond to egg removal than “small-egg” females), but that higher resource levels can overcome individual differences. Egg mass did not vary with laying sequence in supra-normal clutches (up to 22 eggs); however, there was a significant decrease (6%) in yolk protein content of additional eggs that was apparent by the tenth egg laid (i.e. only 4–5 more than the normal clutch size). Plasma levels of the two yolk precursors, vitellogenin and very-low-density lipoprotein (VLDL), were independent of diet and did not differ in individual birds at the 1 egg stage versus the 14 egg stage. However, there was a systematic change in relationship between yolk lipid content and plasma VLDL levels, from nonsignificant for third-laid eggs to significant and positive for sixteenth-laid eggs. We propose a possible mechanism linking female condition and egg-laying ability: good quality females, capable of laying extended clutches, are able to maintain production of generic VLDL for their own metabolic needs, as well as producing yolk-targeted VLDL, whereas poor quality females are not.

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.

scholarly journals Predation risk affects egg mass but not egg steroid hormone concentrations in yellow-legged gulls

2018 ◽  
Vol 65 (4) ◽  
pp. 401-408 ◽  
Author(s):  
Cristina Daniela Possenti ◽  
Alexandra Bea Bentz ◽  
Andrea Romano ◽  
Marco Parolini ◽  
Manuela Caprioli ◽  
...  
Keyword(s):  
Predation Risk ◽  
Clutch Size ◽  
Experimental Treatment ◽  
Egg Laying ◽  
Egg Mass ◽  
Reproductive Decisions ◽  
Lethal Effects ◽  
Cascading Effects ◽  
Larus Michahellis ◽  
And Behavior

AbstractPredators have both direct, consumptive effects on their prey and non-lethal effects on physiology and behavior, including reproductive decisions, with cascading effects on prey ecology and evolution. Here, we experimentally tested such non-lethal effects of exposure to increased predation risk on clutch size, egg mass, and the concentration of yolk steroid hormones in the yellow-legged gull Larus michahellis. We simulated increased predation risk by displaying stuffed predators (adult fox Vulpes vulpes, and adult buzzard Buteo buteo) to breeding adults before egg laying. The concentration of corticosterone, which has been shown to increase under exposure to maternal predation risk in other species, and of testosterone did not differ between eggs from mothers exposed to the predators and eggs from control mothers (i.e., eggs exposed to a novel object of similar size and position to the stuffed predators). The concentration of the two hormones negatively covaried. Clutch size did not vary according to experimental treatment, whereas egg mass was markedly larger in clutches from nests exposed to predators than in clutches from control nests. By increasing egg mass, mothers may reduce the risk of cooling of the eggs when incubation is impeded by predators, boost energy reserves, reduce post-natal detectability caused by food solicitation, and/or enhance development at hatching, thus increasing the chances of offspring survival. In general, our results are inconsistent with most of the few previous studies on similar non-lethal predator effects and suggest that such effects may vary among species according to ecological conditions, social behavior, and developmental mode.

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