Mol Ecol. 2017 Apr;26(8):2392-2404. doi: 10.1111/mec.14035. Epub 2017 Mar 6.
- 1
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein-Allee 11, 89069, Ulm, Germany.
- 2
- Institute of Forest Botany and Forest Zoology, Technical University of Dresden, Pienner Straße 7, 01737, Tharandt, Germany.
Abstract
Sexual
selection involving genetically disassortative mate choice is one of
several evolutionary processes that can maintain or enhance population
genetic variability. Examples of reproductive systems in which choosers
(generally females) select mates depending on their major
histocompatibility complex (MHC) genes have been reported for several
vertebrate species. Notably, the role of MHC-dependent choice not in
mating contexts, but in other kinds of social interactions such as in
the establishment of complex social systems, has not yet drawn
significant scientific interest and is virtually absent from the
literature. We have investigated male and female MHC-dependent choice in
an invasive population of North American raccoons (Procyon lotor) in Germany. Both male and female raccoons
rely on olfaction for individual recognition. Males have an unusually
complex social system in which older individuals choose unrelated
younger ones to form stable male coalitions that defend territories and a
monopoly over females. We have confirmed that females perform
MHC-disassortative mate choice and that this behaviour fosters genetic
diversity of offspring. We have also observed that males build
coalitions by choosing male partners depending on their MHC, but in an
assortative manner. This is the first observation of antagonistic
MHC-dependent behaviours among sexes. We show that this is the only
combination of MHC-dependent partner choice that leads to outbreeding.
In the case of introduced raccoons,
such behaviours can act together to promote the invasive potential of
the species by increasing its adaptive genetic divergence.
© 2017 John Wiley & Sons Ltd.
KEYWORDS:
MHC
;
Procyon lotor
; female mate choice; invasion biology; male coalitions
