Male Reproductive Success is Correlated With Blood Parasite Levels and Body Condition in the Promiscuous Aquatic Warbler (Acrocephalus Paludicola)

The Aquatic Warbler (Acrocephalus paludicola) has a unique mating system. Males are free of any parental duties and can fertilize many females during a single breeding season. Females also usually copulate with more than one male, and nestlings in a single nest may be sired by as many as five males. Paternal success of 33 Aquatic Warbler males in a Polish population was determined by microsatellite polymerase-chain-reaction analysis. Males infected by blood parasites (trypanosomes) sired fewer offspring, weighed less, and probably arrived later to breeding grounds than uninfected males. Number of nestlings sired by a male correlated positively with its fat deposits and wing length. These findings indicate that male body condition directly influences paternal success. Number of sired nestlings per individual male ranged from one to eight. Reproductive success among males was uneven, with six males (18%) fathering 44% of nestlings in the study area. Males with high reproductive success arrived at the breeding grounds earlier in spring than males with low reproductive success.

Genetic analysis of male reproductive contributions in Chamaelirium luteum (L.) gray (Liliaceae).

Genealogical analysis is a powerful tool for analysis of reproductive performance in both natural and captive populations, but assignment of paternity has always been a stumbling block for this sort of work. Statistical methods for determining paternity have undergone several phases of development, ranging from straightforward genetic exclusion to assignment of paternity based on genetic likelihood criteria. In the present study, we present a genetic likelihood-based iterative procedure for fractional allocation of paternity within a progeny pool and apply this method to a population of Chamaelirium luteum, a dioecious member of the Liliaceae. Results from this analysis clearly demonstrate that different males make unequal contributions to the overall progeny pool, with many males contributing essentially nothing to the next generation. Furthermore, the distribution of paternal success among males shows a highly significant departure from (Poisson) randomness. The results from the present analysis were compared with earlier results obtained from the same data set, using likelihood-based categorical paternity assignments. The general biological pattern revealed by the two analyses is the same, but the estimates of reproductive success are only modestly (though significantly) correlated. The iterative procedure makes more complete use of the data and generates a more sharply resolved distribution of male reproductive success.