Egg-size variation in the bluethroat (Luscinia s. svecica): constraints and adaptation

Lifjeld, Jan T.; Johnsen, Arild; Petitguyot, T.

doi:10.1007/s10336-005-0086-5

Cited by 16 publications

(13 citation statements)

References 36 publications

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“…Slagsvold and Lifjeld 1988;Qvarnström et al 2000;Nilsson 2000;Lifjeld et al 2005). Such changes are generally interpreted as an adaptive response to seasonally changing prospects of the oVspring (Drent and Daan 1980;Daan et al 1990;Rowe et al 1994).…”

Section: Introductionmentioning

confidence: 97%

“…For example, seasonal decline in clutch size, which is common in many bird species, may be a strategic adjustment to declining food supply late during the breeding season and to seasonally declining survival prospects of Xedglings (e.g. Slagsvold and Lifjeld 1988;Winkler and Allen 1996;Nilsson 2000;Lifjeld et al 2005). Similarly, hatching asynchrony, which creates a size hierarchy and, hence, competitive asynchrony among siblings often increases with the progress of the breeding season (e.g.…”

Section: Introductionmentioning

confidence: 97%

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Maternal androgens in the pied flycatcher: timing of breeding and within-female consistency

2007

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Maternal hormones can have substantial phenotypic effects in the progeny of many vertebrates. It has been proposed that mothers adaptively adjust hormone levels experienced by particular young to optimize their reproductive output. In birds, systematic variation in egg hormone levels has been related to different female reproductive strategies. Because in many bird species prospects of the offspring change seasonally and with brood number, strategic adjustment of yolk androgen levels would be expected. To test this idea, we induced pied flycatcher (Ficedula hypoleuca) females to nest twice during the same season by removing their first clutches shortly after clutch completion. We collected eggs of first and replacement clutches to measure yolk concentrations of androstenedione (A4) and testosterone (T) and captured the females that laid these clutches for phenotypic measurements. Although average egg androgen levels were remarkably consistent within females, hormone patterns differed considerably between first and replacement clutches. Eggs of replacement clutches were heavier with larger yolks compared to first clutches, but they contained on average lower levels of androgens. Within clutches, androgen concentration increased over the laying sequence in the first clutch, but decreased or remained more constant over the laying sequence in the replacement clutch. Mean yolk T, but not A4 levels, were negatively associated with laying date for both breeding attempts. Moreover, females in good body condition produced eggs containing lower levels of androgens than females in poor condition. Our results are consistent with the idea that differences in yolk androgen levels may be one mechanism underlying seasonal variation in reproductive success and it is possible that changes in egg androgen patterns may reflect a change in female reproductive strategy. High within-female consistency also highlights the possibility that there may be some underlying genetic variation in yolk androgen levels.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

Maternal androgens in the pied flycatcher: timing of breeding and within-female consistency

2007

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“…It can probably be explained by good environmental conditions and/or good quality females, which other authors offer as a plausible explanation (e.g. Järvinen 1996, Lifjeld et al 2005.…”

Section: Disscusionmentioning

confidence: 99%

“…According to Encabo et al (2001), a pos- itive relationship between average egg size and average clutch size would have meant that, in good years, the birds produce large clutches of big eggs, while small clutches of small eggs would be produced in bad years. Furthermore, females in good condition after clutch completion tended to have larger clutches and laid significantly larger eggs in clutches than females in poor condition (Lifjeld et al 2005). All previous researches on trade-off hypothesis in Croatia have illustrated non-significant relationship between clutch size and egg size (Great Tit Parus major, Dolenec et al 2005; Hooded Crow Corvus corone cornix, Dolenec 2006; Tree Sparrow Passer montanus, Dolenec et al 2007;Common Starling Sturnus vulgaris, Dolenec et al 2008 andPied Wagtail Motacilla alba, Dolenec 2011).…”

Section: Disscusionmentioning

confidence: 99%

Is there a trade-off between clutch size and egg volume in Magpie Pica pica in northwestern Croatia?

Dolenec¹

2016

Larus

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A negative relationship, or trade-off, between egg size (egg volume or egg mass) and clutch size is a central component of life-history theory. This paper presents evidence for a relationship between clutch size and egg volume (egg size) of the Magpie (Pica pica). Magpies are common and sedentary birds in study area. Egg characteristics were recorded in Mokrice rural area (46°00'N, 15°55'E), northwestern Croatia; carried out during the breeding season (April-May) in the year 2012. I have not detected any negative correlation (trade-off) between mean estimated egg volume (egg size) and clutch size in the Magpie. The results indicate that, in researched Magpie population, in northwestern Croatia, there is a positively significant correlation between clutch size and egg volume. It can probably be explained by good environmental conditions and/or good quality females, which other authors offer as a plausible explanation. In conclusion, these results do not seem to support the prediction based on the theory of optimal egg/clutch size concerning the inverse relationship between egg size and clutch size.

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“…This is because egg size is only one of the traits that may be affected by climate warming (Both and Visser, 2005), among many others that may be phenotypically and genetically correlated with it (e.g. individual size or condition; see Potti, 1993;Smith et al, 1993;Williams, 1994;Christians, 2002;Yom-Tov, 2001;Lifjeld et al, 2005). Furthermore, adjustment of egg size to changes in environmental phenology, if any, will depend to a certain degree on a previous adjustment of bird phenology to the phenology of the changing environment.…”

Section: Introductionmentioning

confidence: 99%

Temperature during egg formation and the effect of climate warming on egg size in a small songbird

Potti

2008

Acta Oecologica

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Keywords:Breeding phenology revealed that despite females consistently laying larger eggs when they experienced warmer temperatures during the prelaying and laying periods, there was an overall negative response -i.e. decreasing egg volume and breadth with increasing spring (May) average temperatures -across individuals. This trend is hypothesised to be caused by the mismatched breeding phenology, in relation to climate warming, of this population. Except in the unlikely cases of populations capable of perfectly synchronising their phenology to changes in their environment, maladjustments are likely for traits such as egg size, which depend strongly on female condition. Slight changes or absence thereof in breeding dates may be followed by mismatched dates, in terms of food abundance, for optimal egg formation, which would be reflected in smaller average egg size, contrary to early predictions on the effects of climate warming on bird egg size..

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Egg-size variation in the bluethroat (Luscinia s. svecica): constraints and adaptation

Cited by 16 publications

References 36 publications

Maternal androgens in the pied flycatcher: timing of breeding and within-female consistency

Maternal androgens in the pied flycatcher: timing of breeding and within-female consistency

Is there a trade-off between clutch size and egg volume in Magpie Pica pica in northwestern Croatia?

Temperature during egg formation and the effect of climate warming on egg size in a small songbird

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