Study On The Anti-parasitism Strategies Of A Potential Host Of The Common Cuckoo-the Daurian Redstart(Phoenicurus Auroreus)

Avian brood parasitism is a special reproductive behavior in birds.Parasitic birds lay their eggs in the nests of other species and leave the foster parents(hosts)to rear chicks for them.Anti-parasitism is an important evolved adaptation for hosts under parasitic pressure.In this study,nesting,egg laying,hatching,and brooding behaviors of Daurian Redstart(Phoenicurus auroreus)were systematically studied through measuring of nest site selection,breeding time,egg color mutation,egg recognizition,parasite discrimination,nest defense,and fledgling feeding habits to reveal the low parasitism rate of Daurian Redstart breeding in Liaoning Province.The results are as follows:(1)A total of 44 valid nest-site data were collected in 2017.Principal components analysis showed that the major factors behind nest-site selection were nest entrance,spatial location,sunshine,human disturbance,nest security,and nest concealment.The nests are generally narrow gaps that can prevent parasitoids from entering the spawning,and the nests are high in concealment.The Daurian Redstart prefers living together with human while most of their nests are close to buildings and roads.(2)The first-egg laying date of the Daurian Redstart and breeding date of the Common cuckoo were surveyed.Results showed that the peak spawning of the Daurian Redstart was significantly earlier than the arrival time of the Common cuckoo.Furthermore,the egg laying and brooding time of the Daurian Redstart were significantly shorter than the other passerine birds.(3)During the experiment,a total of 44 nests egg colors were collected.The Daurian Redstart population in Liaoning had two egg color mutations that were cyan and white.The ratio of nests producing white eggs to nests producing green eggs was close to 1:1.Genotyping experiments showed that there were different at Cytb and COI in two egg colors indicated the Daurian Redstart in this area is composed of two population lines.(4)Rejection behaviors were collected during the experimental process(n=33).The rejection rate of the Daurian Redstart in Liaoning province to blue mimetic egg was 83.84%,which was significantly higher than that of other area.The main way to model eggs is to pull the eggs out of the nest.(5)A total of 19 nests defense and 24 nest Cuckoo specimen identification data were collected.The local Daurian Redstart showed aggressive defense behaviors,while they did not exhibit identification ability toward cuckoos in the presence.The response to the specimen was unresponsive or whispered,and the response intensity of the female was higher than the male?s.However,the males have a stronger alertness than females in the oviparous period.(6)A videos of the brooding period of the Daurian Redstart were recorded(n=16).The video analysis showed that the average frequency of brooding was 11.388 times per hour,and the frequency was relatively higher than the other passerine birds.There are nearly 18% of hitin-bearing beetle in the nestling food,which are indigestible for cuckoo.In conclusion,our studies showed that the nest site of the Northern Redstart has anti-parasitic characteristics,and the two egg color mutations,strong egg recognition capability make it extremely difficult to parasites.The egg laying and brooding time of most Daurian Redstart in Liaoning province cleverly avoided the breeding period of the big cuckoo.The food composition of the fledgling chicks is also a special anti-parasitic strategy.These behaviors of Daurian Redstart have some anti-parasite parasitic meaning.It is the important reason for the low parasitism rate of the Daurian Redstart in Liaoning Province.