Morisaka, T. and R. Connor (2007): Predation by killer whales (Orcinus orca)
and the evolution of whistle loss and narrow-band high frequency clicks in
odontocetes. Journal of Evolutionary Biology 20 (4), 1439-1458.
Abstract: A disparate selection of toothed whales (Odontoceti) share
striking features of their acoustic repertoires including the absence of
whistles and high frequency but weak (low peak-to-peak source level) clicks
that have a relatively long duration and a narrow bandwidth. The
non-whistling, high frequency click species include members of the family
Phocoenidae, members of one genus of delphinids, Cephalorhynchus, the pygmy
sperm whale, Kogia breviceps, and apparently the sole member of the family
Pontoporiidae. Our review supports the 'acoustic crypsis' hypothesis that
killer whale predation risk was the primary selective factor favouring an
echolocation and communication system in cephalorhynchids, phocoenids and
possibly Pontoporiidae and Kogiidae restricted to sounds that killer whales
hear poorly or not at all (< 2 and > 100 kHz).
URL:
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1420-9101.2007.01336.x
For reprints please contact: Tadamichi Morisaka
Routtu, J.,Mazzi, D., Van der Linde, K., Mirol, P., Butlin, R. K. and A.
Hoikkala (2007): The extent of variation in male song, wing and genital
characters among allopatric Drosophila montana populations. Journal of
Evolutionary Biology 20 (4), 1591-1601.
Abstract: Drosophila montana, a species of the Drosophila virilis group, has
distributed around the northern hemisphere. Phylogeographic analyses of two
North American and one Eurasian population of this species offer a good
background for the studies on the extent of variation in phenotypic traits
between populations as well as for tracing the selection pressures likely to
play a role in character divergence. In the present paper, we studied
variation in the male courtship song, wing and genital characters among
flies from Colorado (USA), Vancouver (Canada) and Oulanka (Finland)
populations. The phenotypic divergence among populations did not coincide
with the extent of their genetic divergence, suggesting that the characters
are not evolving neutrally. Divergence in phenotypic traits was especially
high between the Colorado and Vancouver populations, which are closer to
each other in terms of their mtDNA genotypes than they are to the Oulanka
population. The males of the Colorado population showed high divergence
especially in song traits and the males of the Vancouver population in wing
characters. Among the male song traits, two characters known to be under
sexual selection and a trait important in species recognition differed
clearly between populations, implying a history of directional and/or
diversifying rather than balancing selection. The population divergence in
wing characters is likely to have been enhanced by natural selection
associated with environmental factors, whereas the male genitalia traits may
have been influenced by sexual selection and/or sexual conflict.
URL:
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1420-9101.2007.01323.x
For reprints please contact: J. Routtu
Kind regards
Sonja
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University of Vienna, Dept. of Behavioural Biology
Sonja Amoser
PhD
Althanstrasse 14
1090 Vienna
Austria
tel: +43 (1) 4277 54467
fax: +43 (1) 4277 54506
mobile: +43 (664) 500 61 06
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