Components of lifetime reproductive success in communally and solitarily nursing house mice — a laboratory study

Abstract

Under laboratory conditions, communal nursing among familiar and closely related female house mice (Mus domesticus) improved lifetime reproductive success

A reduced propensity to cooperate under enhanced exploitation risk in a social mammal

“…Dominance among the females might determine the order in which they contribute to a communal nest and consequently which of the females is going to benefit more. Laboratory studies, however, did not reveal any signs for behavioural dominance among pairs of cooperating full sisters [24]. As soon as the litters in a communal nest are mixed, females invest according to the total number of pups in the joint nest [28] and have only limited options to prevent exploitation by the social partner.…”

“…Following Kö nig [24], we defined a communal nest as two litters being born within 17 days of each other and being raised in one nest. When litters were more than 17 days apart in age, we did not consider this as a communal nest, because the older litter was no longer fully dependent on milk and had only a small influence on female investment.…”

“…Infanticide towards pups that are not their own has been described for female house mice and other mammals and birds, with females giving birth (or laying eggs) first being more susceptible to infanticide [24,29,30]. Considering that females are unable to discriminate between own and alien offspring, they should only be infanticidal while still pregnant.…”

Communal nursing in wild house mice is not a by-product of group living: Females choose

“…Laboratory studies on mice and rats describe improved growth or survival of own offspring (Sayler and Salmon 1969; Mennella et al 1990; Heiderstadt and Blizard 2011), and even improved lifetime reproductive success for females that nurse communally (König 1993, 1994a). …”

“…Southwick 1955; Sayler and Salmon 1969; Wilkinson and Baker 1988; König 1993; Manning et al 1995). Laboratory studies with wild house mice show mutualistic and direct fitness benefits of communal nursing, which are modified by familiarity and by group size (König 1994a, b). Indeed, females display non-random preferences for social partners when kept in enclosures.…”