Striped mongoose, born in the result of inbreeding, less likely to participate in the care of the offspring. Although help adults greatly increases the chances of inbred cubs survival, then they themselves are reluctant to remain with the kids in burrows and rarely accompany them during the search for food. Thus, it is noted in the article for the journal Ecology Letters, altruistic behavior can not fully compensate for the negative effects of inbreeding.
Most animals try to avoid inbreeding, as it affects the health of offspring. For example, long-tailed tit (Aegithalos caudatus) learn children and parents and not mate with them.
However, in some species, which lead a collective way of life, inbreeding occurs regularly. Scientists suggest that the negative effects of such behavior kompensiruet they have a strong development of altruism. The fact that each individual within the group a lot of shared genes with relatives, which makes the help they benefit from the genetic point of view. First of all it concerns care for others ‘ young.
The hypothesis of an Association of inbreeding with altruism seems logical, however it lacks solid evidence. To find them was decided by the team headed by hazel Nichols (Hazel J. Nichols) from Swansea University.
As the object of study they chose the striped mongooses (Mungos mungo). These small predators from the African Savannah live in groups of 15-20 individuals without a strict hierarchy, which consist mainly of relatives. In reproduction involves many members of the group, and some couples include fathers and daughters or full siblings. According to calculations, the fruits of such unions are about nine percent of the young. They are weaker than dogs and worse multiply, but their survival is not reduced.
Researchers analyzed information about the behavior and relationships of the striped mongoose, which for 21 years was collected in a National Park Queen Elizabeth in Uganda. Here are situated the model area, where always dwells 10-12 family groups of these mammals (a total of about 200 individuals). In the analysis included records about 2023 hours observing mongooses and genetic relationships of 1125 individuals.
For striped mongoose is characterized by two species care for their offspring, including someone else’s: adults can remain with young pups in the den or accompany in search of food when they get a little older. The team focused on the behavior.
It turned out that the care of relatives has a positive effect on weight and survival of inbred young. Unaccompanied until the age of 90 days, survive only a quarter of these kids. However, the help of adults increases this figure to three quarters, this level is characteristic of normal cubs. However, contrary to expectations of researchers, inbred cubs don’t get more adult attention than usual.
Thanks to the help of relatives, the negative effects of inbreeding in pups markedly reduced (though not eliminated entirely). However, when these kids grow up, they themselves are reluctant to participate in the care of the offspring. Observations have shown that inbred individuals of both genders are less likely to remain with the cubs in burrows and inbred males are less likely to accompany them during the search for food. Given that young mongoose two-thirds receive care from males, is a substantial decline.
The authors conclude that altruistic behavior that occurs as a result of family screening indeed reduces the negative effects of inbreeding. However, it can not compensate for them completely: for example, the low level of care for the offspring, which show inbred individuals, reduces the fitness of the entire group.
Rather, there are other mechanisms that maintain a high level of inbreeding in the populations of striped mongooses. According to the authors, this may be a low survival rate of individuals who leave their native group. The result is more profitable for them to stay in the family, even if it may lead to a pairing with close relatives.
The behavior of striped mongooses have long been in the focus of scientists. Only in recent years they found out that among these predators is “macho” and altruistic, and a difficult childhood increases their chances of a long life. In addition, mongoose has detected embryonic signs of culture: young individuals have them adopt the habits of the guardians.
Sergey Knee High