Lauryn Benedict (2008): Unusually high levels of extrapair paternity in a
duetting songbird with long-term pair bonds. Behav. Ecol. Sociobiol. 62(6),
983-988.
Abstract: Previous studies suggest that extrapair young are very rare or
absent in socially monogamous avian species that produce vocal duets. These
results are generally consistent with functional hypotheses suggesting that
duets may signal commitment between partners, or aid males as a paternity
guard to ensure genetic as well as social monogamy. Additionally, species
that exhibit social monogamy with the same partner across multiple breeding
seasons tend to exhibit low levels of extrapair paternity, so duetting
species that mate for life may be particularly likely to exhibit genetic
monogamy. This study examined the social and genetic mating systems of
California towhees (Pipilo crissalis), a duetting species thought to have
life-long pair bonds. Observation of a color-banded population confirmed
that California towhees exhibit long-term social monogamy. Known social
families were genotyped at four microsatellite loci with high allelic
diversity. Unexpectedly, paternity exclusion indicated that at least 13 of
31 (42%) nests contained extrapair young. All chicks exhibited maternal
alleles, but 21 of 81 (26%) young were not the offspring of social fathers.
Thus, in contrast to previous work, this study documents high frequencies of
extrapair young among socially monogamous duetting birds with long-term pair
bonds.
URL: http://www.springerlink.com/content/e11574k7j7m8j16r/
For reprints please contact Lauryn Benedict (Email:
A. Lemasson, R. A. Palombit and R. Jubin (2008): Friendships between males
and lactating females in a free-ranging group of olive baboons ( Papio
hamadryas anubis ): evidence from playback experiments. Behav. Ecol.
Sociobiol. 62(6), 1027-1035.
Abstract: Close association between an anoestrous female at the time of
lactation and adult male(s) is relatively rare in mammals, but common in
baboons (Papio hamadryas subsp.). The functional significance of these
"friendships" remains unclear, however. In chacma baboons (P. h. griseipes),
friendships are a counter-strategy to infanticide by immigrant males.
Experimental playback of female distress calls in chacma baboons revealed
that male friends are more motivated to protect females and infants than are
control males. Olive baboons (P. h. anubis) also exhibit friendships, but
infanticide is rare, suggesting that friendships provide females with
protection from non-lethal aggression (anti-harassment hypothesis) or serve
to promote male-infant bonds that later benefit the maturing juvenile
(future male caretaker hypothesis). We replicated these playback experiments
on a group of olive baboons to test between these hypotheses and to evaluate
if the lower costs of non-lethal harassment lessens male protective
responsiveness relative to protection from (more costly) infanticide.
Spatial data revealed that most lactating females had one to four friend
males. Relative to non-friends, friend dyads were characterized by higher
rates of allogrooming and infant handling, but less agonism. Female rank was
correlated with the number of male friends. Just as in chacma baboons,
playback of female screams elicited stronger responses from male friends
than control males in support the anti-harassment hypothesis. Compared to
the chacma baboon, male olive baboons appeared to exhibit similarly high
levels of protective solicitude for female friends although they protect
against non-lethal harassment rather than infanticide.
URL: http://www.springerlink.com/content/g645632w42712t41/
For reprints please contact A. Lemasson (Email:
Kind regards
Sonja Amoser
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