Genomic analysis of Tibetan ground tits identifies molecular adaptations associated with cooperative breeding

Cooperative breeding is a sophisticated altruistic social behavior that helps social animals to adapt to harsh environments.The Tibetan ground tit,Pseudopodoces humilis,is a high-altitude bird endemic to the Tibetan plateau.Recently,it has become an exciting system for studying the evolution of facultative cooperative breeding.To test for molecular adaptations associated with cooperative breeding,we resequenced the whole genome of ground tits from 6 wild populations that display remarkable variation in the frequency of cooperative breeding.Population structure analyses showed that the 6 populations were divided into 4 lineages,which is congruent with the major geographical distribution of the sampling sites.Using genome-wide selective sweep analysis,we identified putative positively selected genes(PSGs)in groups of tits that displayed high and low cooperative breeding rates.The total number of PSGs varied from 146 to 722 in high cooperative breeding rate populations,and from 272 to 752 in low cooperative breeding rate populations.Functional enrichment analysis of these PSGs identified several significantly enriched ontologies related to oxytocin signaling,estrogen signaling,and insulin secretion.PSGs involved in these functional ontologies suggest that molecular adaptations in hormonal regulation may have played important roles in shaping the evolution of cooperative breeding in the ground tit.Taken together,our study provides candidate genes and functional ontologies involved in molecular adaptations associated with cooperative breeding in Tibetan ground tits,and calls for a better understanding of the genetic roles in the evolution of cooperative breeding.

Breeding ecology of ground tits in northeastern Tibetan plateau, with special reference to cooperative breeding system

Data on breeding ecology of a color-band marked population of the ground tit Parus humilis were collected in north Qinghai on the Tibetan plateau, during 2008 and 2009. In spring the birds excavated 0.8-3.2 m long nesting burrows under the ground. First-egg laying occurred between late April and late June during which a pair produced one brood. Incubation was done by female alone for 15-16 days and nestling-feeding by both sexes and helpers in any for 23-25 days. Average brood size at fledging was 5.8 （＋ 1.4 SD, 3-8） and all the 27 observed nesting attempts fledged at least one young. At the population level, brood sex ratio did not differ from 1：1. The birds are a territory-living resident, with annual resight rates being 48% （22 of 46） in adult breeders and 10% （7 of 67） in yearlings. Pairs were socially monogamous, of which 23% （9 of 40） contained one and some- times two male helpers, most likely being philopatric sons of the breeders. The formation of cooperative groups is similar to the population in central Tibet but differs from that in south Guansu where breeding ground tits exhibit a high level of annual turnover

Breeding ecology of two sympatric laughingthrushes(Trochalopteron milnei and Garrulax berthemyi)in southwestern China

Here we documented up-to-date information on breeding ecology of Buffy Laughingthrush(Garrulax berthemyi),an endemic species of China,and a sympatric coordinal Red-tailed Laughingthrush(Trochalopteron milnei),in southwestern China.Furthermore,we compared breeding ecology of these two sympatric species.No significant differences were found in clutch size,egg size,nest size,nest height,nest habitat and predation rate between these two species except nests depth,nests cover and eggs color.The Red-tailed Laughingthrush nestlings differed from those of the Buffy Laughingthrush in gape morphology and the extent of down.Observation of breeding behavior showed that cooperative breeding might exist in the population of Buffy Laughingthrush.

Complementary interactions between indirect and direct fitness in a cooperatively breeding

Altruism is difficult to explain evolutionarily and to understand it,there is a need to quantify the benefits and costs to altruists.Hamilton’s theory of kin selection argues that altruism can persist if the costs to altruists are offset by indirect fitness payoffs from helping related recipients.Nevertheless,helping nonkin is also common and in such situations,the costs must be compensated for by direct benefits.While previous researchers tended to evaluate the indirect and direct fitness in isolation,we expect that they have a complementary interaction where altruists are associated with recipients of different relatedness within a population.The prediction is tested with 12years of data on lifetime reproductive success for a cooperatively breeding bird,Tibetan ground tits Pseudopodoces humilis.Helpers who helped distantly related recipients gained significantly lower indirect benefits than those who helped closely related recipients,but the opposite was true for direct fitness,thereby making these helpers have an equal inclusive fitness.Helping efforts were independent of helpers’relatedness to recipients,but those helping distantly related recipients were more likely to inherit the resident territory,which could be responsible for their high direct reproductive success.Our findings provide an explanatory model for the widespread coexistence of altruists and recipients with varying relatedness within a single population.

Operating in Tandem Chinese experts in Sao Tome and Principe cooperate with local farmers to raise medical standards in the breeding industry

Santomean pig farmer Simao Vicente was hopeful when he came to ask Zou Rui for help. His pig was suffering from hernia, and Zou, a 42-year-old Chinese agricultural expert working in Sao Tomé and Príncipe, was the only person on the island who could provide emergency surgery.