To mate or not to mate? Mate preference and fidelity in monogamous Ansell’s mole-rats, Fukomys anselli, Bathyergidae

In: Folia Zoologica, Jg. 61 (2012) ; Nr. 1, S. 71-83
ISSN: 0139-7893
Zeitschriftenaufsatz / Fach: Biologie
Fakultät für Biologie » Allgemeine Zoologie
According to a hypothesis addressing the evolution of eusociality in mole-rats, the female (queen)
is not able to raise her (first) offspring without a mate and thus to found a family. Therefore, we predict that
the reproductive male (king) has to be socially faithful. In this study we tested this prediction and addressed
the related question whether or not the presentation of a new female provokes enhanced sexual interest in male
Ansell’s mole-rats (Fukomys anselli).
We performed behavioral partner preference tests in Ansell’s mole-rats where two animals of choice were
presented to a subject without allowing direct access. The kings spent significantly more time sniffing an unfamiliar
queen or female than their own mate. If given the choice between an unfamiliar queen and her respective
non-reproductive daughter, however, the tested kings significantly preferred the queen. In contrast, queens did
not show a preference for either their own mate, an unrelated unfamiliar king, or a non-reproductive male.
In a second experiment, we allowed the males to access the compartment of an unfamiliar female while their respective
family stayed in an adjacent compartment. Only the non-reproductive adult males seized their chances
to copulate with the unfamiliar female whereas the kings remained faithful. When reversing the test condition
(i.e. females were given access to an unfamiliar male), aggressiveness of the males impeded sexual encounters
in most cases. We recorded only three copulations, all of them between queens and non-reproductive males.
We conclude that the reproductive status is crucial for reproductive decisions. Furthermore, the presence of
family members influences the kings’ behavior. Since in Ansell’s mole-rats, repeated copulations over a longer
period of cohabitation are necessary for ovulation and fertilization, the kings’ sexual fidelity could have been
expected. We postulate that the maintenance of Ansell’s mole-rats’ families depends on the kings’ faithfulness.