Sociobiology of bank swallows: reproductive strategy of the male.

The function of long tails in female barn swallows {Hirundo rustica): an experimental study

The outermost tail feathers in male barn swallows {Hirundo rustica) are the target of a strong directional female mate preference. The" tait ornament is also expressed in females, since females have considerably longer tails than juveniles, either due to (1) a strong genetic correlation between the characters in the two sexes, or (2) direct sexual selection on females. To discriminate between t...

The Reproductive Benefits of Religiosity Empirical findings of Religion, Reproduction and Female Choice towards a Sociobiology of Religion

Female receptivity, embryonic diapause, and superfetation in the European badger (Meles meles): implications for the reproductive tactics of males and females.

The European badger Meles meles is thought to mate throughout the year with two mating peaks occurring in late winter/spring and summer/autumn. After mating, fertilized ova enter embryonic diapause (delayed implantation) at the blastocyst stage, which lasts up to eleven months. Even if mating is successful, however, the estrous cycle may continue during embryonic diapause, which suggests that f...

The Sociobiology of Sexual and Reproductive Strategies

Evolution occurs by natural selection, and since natural selection operates through differential reproduction, reproduction is the key phenomenon of evolution. Hence alI organisms compete for reproductive success, as a means of maximizing inclusive fitness. However, there are many examples of social animals adopting altruistic behaviour, postponing or even foregoing their own reproduction while...

Variation in the Costs, Benefits, and Frequency of Nest Reuse by Barn Swallows (hirundo Rustica)

ABSTP•CT.--The frequency of nest reuse and the costs and benefits of this behavior were investigated in a population of Barn Swallows (Hirundo rustica) at Delta Marsh, Manitoba, during 1984-1986. Slightly less than half the clutches were laid in old nests, and this proportion did not change seasonally except in one late year when old nests were preferred by late-nesting pairs. The delay between...