Roosters are nicer to their relatives than to other males

Date: March 29, 2017

Source: Linköping Universitet

Male domestic fowl are less aggressive towards related males than to unrelated males when competing for copulations, according to a new study from Linköping University in Sweden. This finding, which has been published in the scientific journal Behavioral Ecology, suggests that domestic fowl can recognise their kin among individuals in a group, and that their behaviour is different towards kin and non-kin.

Domestic fowl in groups form a strict hierarchy, with one rooster being dominant over the others. The roosters compete for access to hens to mate with, and in this way produce offspring and transmit their genes to the next generation. If a rooster that is lower in the ranking attempts to mate with a hen, the dominant male will often interrupt and abort the mating attempt.

The researchers who conducted the study investigated if roosters not only attempt to produce offspring themselves but also to help relatives to do so. From an evolutionary perspective, this would be a way of ensuring that at least some of the male's genes are transmitted to the next generation. Particularly older males, with reduced reproductive capacity, may be more accepting towards younger relatives mating attempts. Thus, the researchers wanted to determine whether dominant roosters are more permissive towards the attempted matings of subordinate relatives than to those of unrelated lower-ranked males. They divided the chickens into groups with one dominant male and two roosters of lower rank; one of which was brother or son of the dominant male, and one that was unrelated to him. The three roosters were released together with four hens, and the researchers observed their mating behaviour.

Continued

Animals' infections can impact most on relatives, study finds

Date: July 7, 2015

Source: University of Edinburgh

Summary: Disease in wild animals can have a greater impact on the health of others than on the infected animals themselves, a study suggests. Research in families of wild seabirds reveals for the first time how parasite infection in some can have a serious effect on how well their relatives do.

It is not clear why infection in some birds can affect others, but scientists suggest it may affect adults' ability to nurture their young, or that infected chicks may need more care.

The findings could have important implications for the conservation of wild animals, including seabirds, which are under threat.

Scientists from The University Of Edinburgh and the Centre For Ecology And Hydrology studied the impact of disease on families of cormorant-like birds, known as shags, on the Isle of May National Nature Reserve off Scotland's east coast during the breeding season.

They found that worm infection in parent birds or their nestlings impacted most on others in their family group.

Continued ...