Plastering mud around the entrance hole affects the estimation of threat levels from nest predators in Eurasian Nuthatches

Background:For cavity-nesting birds,the nest entrance plays an important role in preventing predators from accessing nests.Several species of nuthatches use mud to narrow the entrance of cavities.In theory,the smaller the entrance hole size,the more effective it is against predators;however,few studies have tested whether narrowing the entrance hole size can affect the estimation of threat levels from nest predators in cavity-nesting birds.Methods:Using dummy experiments,we tested whether Eurasian Nuthatches(Sitta europaea,narrow the entrance hole of cavities)and Cinereous Tits(Parus cinereus,do not narrow the entrance hole,as a control)perform different nest defence behaviours against Common Chipmunks(Tamias sibiricus,small nest predator)and Red Squirrels(Sciurus vulgaris,larger nest predator).Results:Both nuthatches and tits exhibited stronger response behaviours(high dummy response scores)against chipmunks than against squirrels.Compared with tits,nuthatches exhibited more aggressive behaviours to chipmunks,but their responses to squirrels were similar.Conclusions:Nest defence behaviours of nuthatches to chipmunks differed from tits,and the results suggested that nuthatches might estimate threat levels of nest predators according to their narrowed entrance-hole size.

Hepatic microRNA-126 deficiency restrains liver regeneration through p53 pathway in mice

Dear Editor,Emerging evidences show close associations between miRNAs and liver regeneration.MiR-126 is known as a governor of vascular integrity and angiogenesis.MiR-126 is involved in the self-renewal of hematopoietic stem cells(HSCS)and leukemia stem cells.1,2 MiR-126 also plays a vital role in hepatocellular carcinogenesis,however,the functions of miR-126 in liver regeneration were still unclear.