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Ovulation order mediates a trade-off between pre-hatching and post-hatching viability in an altricial bird.

Sockman KW - PLoS ONE (2008)

Bottom Line: However, this perspective ignores the potential effect of laying order on pre-hatching viability, an effect which some studies suggest should offset the effect of laying order on post-hatching viability.This effect of laying order on pre-hatching viability seemed to offset that on post-hatching viability, and, consistently, maternal investment in egg size varied little if at all with respect to laying order.These results suggest that ovulation order mediates a trade-off between pre-hatching and post-hatching viability and should encourage a re-evaluation of the solitary role post-embryonic survival often plays when researchers make assumptions about the value of propagules based on the order in which they are produced.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America. kws@unc.edu

ABSTRACT
Simultaneously dependent siblings often compete for parentally provided resources. This competition may lead to mortality, the probability of which may be a function, in part, of the individual offspring's production order. In birds, serial ovulation followed by hatching asynchrony of simultaneous dependents leads to differences in post-hatching survival that largely depend on ovulation (laying) order. This has led to the widespread assumption that early-laid eggs are of greater value and therefore should possess different maternally manipulated characteristics than later-laid eggs. However, this perspective ignores the potential effect of laying order on pre-hatching viability, an effect which some studies suggest should offset the effect of laying order on post-hatching viability. I examined the relationship between laying order and hatching and fledging probability in wild, free-living Lincoln's sparrows (Melospiza lincolnii). In broods with complete hatching success, first-laid and therefore first-hatched offspring had the highest probability of fledging, and fledging probability declined with increasing laying order. However, first-laid eggs were less likely than later-laid eggs to hatch. This effect of laying order on pre-hatching viability seemed to offset that on post-hatching viability, and, consistently, maternal investment in egg size varied little if at all with respect to laying order. These results suggest that ovulation order mediates a trade-off between pre-hatching and post-hatching viability and should encourage a re-evaluation of the solitary role post-embryonic survival often plays when researchers make assumptions about the value of propagules based on the order in which they are produced.

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Relationship between laying order and hatching and then fledging probability in Lincoln's sparrows propagules.Numbers of propagules in each category are indicated at the base of bars.
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pone-0001785-g004: Relationship between laying order and hatching and then fledging probability in Lincoln's sparrows propagules.Numbers of propagules in each category are indicated at the base of bars.

Mentions: The results so far raise the possibility that the elevation in pre-hatching viability offsets the decline in post-hatching viability with the transition from first- to middle-ovulated propagules, potentially making it no more likely that first-laid propagules would remain viable through the complete nesting cycle than later-laid propagules would. I analyzed probability to remain viable from laying through hatching and then fledging, with egg (N = 137) nested within brood (N = 60) and with the independent contrasts for laying order as predictors. I also included date of clutch initiation, egg volume, and the independent contrasts for clutch size and year as predictors to control for these potential effects. Probability of hatching and then fledging did not change with respect to laying order (Table 1) and hovered around 0.35 regardless of laying order (Figure 4). Interestingly, probability of surviving through to fledging declined with date of clutch initiation, declined from 2005 to 2006, and then increased from 2006 to 2007 (Table 1). I found no effect of clutch size or egg volume.


Ovulation order mediates a trade-off between pre-hatching and post-hatching viability in an altricial bird.

Sockman KW - PLoS ONE (2008)

Relationship between laying order and hatching and then fledging probability in Lincoln's sparrows propagules.Numbers of propagules in each category are indicated at the base of bars.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2262150&req=5

pone-0001785-g004: Relationship between laying order and hatching and then fledging probability in Lincoln's sparrows propagules.Numbers of propagules in each category are indicated at the base of bars.
Mentions: The results so far raise the possibility that the elevation in pre-hatching viability offsets the decline in post-hatching viability with the transition from first- to middle-ovulated propagules, potentially making it no more likely that first-laid propagules would remain viable through the complete nesting cycle than later-laid propagules would. I analyzed probability to remain viable from laying through hatching and then fledging, with egg (N = 137) nested within brood (N = 60) and with the independent contrasts for laying order as predictors. I also included date of clutch initiation, egg volume, and the independent contrasts for clutch size and year as predictors to control for these potential effects. Probability of hatching and then fledging did not change with respect to laying order (Table 1) and hovered around 0.35 regardless of laying order (Figure 4). Interestingly, probability of surviving through to fledging declined with date of clutch initiation, declined from 2005 to 2006, and then increased from 2006 to 2007 (Table 1). I found no effect of clutch size or egg volume.

Bottom Line: However, this perspective ignores the potential effect of laying order on pre-hatching viability, an effect which some studies suggest should offset the effect of laying order on post-hatching viability.This effect of laying order on pre-hatching viability seemed to offset that on post-hatching viability, and, consistently, maternal investment in egg size varied little if at all with respect to laying order.These results suggest that ovulation order mediates a trade-off between pre-hatching and post-hatching viability and should encourage a re-evaluation of the solitary role post-embryonic survival often plays when researchers make assumptions about the value of propagules based on the order in which they are produced.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America. kws@unc.edu

ABSTRACT
Simultaneously dependent siblings often compete for parentally provided resources. This competition may lead to mortality, the probability of which may be a function, in part, of the individual offspring's production order. In birds, serial ovulation followed by hatching asynchrony of simultaneous dependents leads to differences in post-hatching survival that largely depend on ovulation (laying) order. This has led to the widespread assumption that early-laid eggs are of greater value and therefore should possess different maternally manipulated characteristics than later-laid eggs. However, this perspective ignores the potential effect of laying order on pre-hatching viability, an effect which some studies suggest should offset the effect of laying order on post-hatching viability. I examined the relationship between laying order and hatching and fledging probability in wild, free-living Lincoln's sparrows (Melospiza lincolnii). In broods with complete hatching success, first-laid and therefore first-hatched offspring had the highest probability of fledging, and fledging probability declined with increasing laying order. However, first-laid eggs were less likely than later-laid eggs to hatch. This effect of laying order on pre-hatching viability seemed to offset that on post-hatching viability, and, consistently, maternal investment in egg size varied little if at all with respect to laying order. These results suggest that ovulation order mediates a trade-off between pre-hatching and post-hatching viability and should encourage a re-evaluation of the solitary role post-embryonic survival often plays when researchers make assumptions about the value of propagules based on the order in which they are produced.

Show MeSH
Related in: MedlinePlus