The Effect of Differential Reproductive Success on Population Genetic Structure: Correlations of Life History With Matrilines in Humpback Whales of the Gulf of Maine

To examine whether demographic and life-history traits are correlated with genetic structure, we contrasted mtDNA lineages of individual humpback whales (Megaptera novaeangliae) with sighting and reproductive histories of female humpback whales between 1979 and 1995. Maternal lineage haplotypes were obtained for 323 whales, either from direct sequencing of the mtDNA control region (n = 159) or inferred from known relationships along matrilines from the sequenced sample of individuals (n = 164). Sequence variation in the 550 bp of the control region defined a total of 19 maternal lineage haplotypes that formed two main clades. Fecundity increased significantly over the study period among females of several lineages among the two clades. Individual maternal lineages and other clades were characterized by significant variation in fecundity. The detected heterogeneity of reproductive success has the potential to substantially affect the frequency and distribution of maternal lineages found in this population over time. There were significant yearly effects on adult resighting rates and calf survivorship based on examination of sighting histories with varying capture-recapture probability models. These result

Hatching Asynchrony and Brood Reduction in Blue Tits Cyanistes caeruleus may be a Plastic Response to Local Oak Bud Burst and Caterpillar Emergence.

Blue tits exhibit extreme variation in clutch size and hatching asynchrony, which is the focus of this study. This paper reports an in-depth study of breeding blue tits showing that variation in blue tit hatching asynchrony can be explained by a number of phenological variables including particularly, date of bud burst in the local oak tree, which signals caterpillar emergence (34%), also date of first egg (14%) and female weight (8%). Hatching asynchrony explained 9% of the variation in brood mortality in this southern English population. Early incubation relative to clutch completion (incubation asynchrony) in blue tits explained 85% of the variation in hatching asynchrony, differs between years and advanced hatching in early and fledging in late laid eggs. Consequently, because fledging is usually synchronous, hatching asynchrony shortens the total time spent in the nest and explained 28% of the variation in total nesting time from clutch completion to fledging. I present experimental evidence that brood reduction resulting from hatching asynchrony may be particularly adaptive towards the end of the breeding season, with 91% of the variation in the productivity of asynchronously hatched birds being explained by, and increasing with date of hatching. About one fifth of birds delayed daytime incubation until after clutch completion, probably in wait for the caterpillars to appear. Although the delay period was variable, and extended total nesting time it always resulted in synchronous hatching. I propose that blue tits may have evolved plastic responses to environmental cues such as oak bud burst, which causes them to incubate at the optimum time to ensure maximum fledging success and chick fitness