Anti-parasitism Strategy Of Sympatric Brown Breasted Bulbul(Pycnonotus Xanthorrhous)and Collared Finchbill(Spizixos Semitorques)in Difference Breeding Period

Avian brood parasitism is a text book of coevolution researching in biology ecology.Hosts evolved variety antiparasitism strategies to minimize of the cost of cuckoo parasitic,and the coevolution between cuckoo and its hosts throughout the whole breeding process of hosts.In this study,the relationship of coevolution between two sympatric Pycnonotidae and their potential parasites had been investigated,and discussing the Pycnonotidae ecology adaption for brood parasitic in their nesting,incubating and nestling period.The main results and conclusions as follow:1.We studied the nest site selection of two Pycnonotidae species in Kuankuoshui National nature reserve in Guizhou province during bird breeding of 2014-2016(Apr.-Aug.).The result shows that the forest edge provide the most of cuckoo perches in study area and the host nest which close to the forest edge may enduring more risk of parasitism.Brown breasted Bulbul(Pycnonotus xanthorrhous)more like to building nests near to the people habitat and far away from forest edge than Collared Finchbill(Spizixos semitorques).The breeding density of Bulbul is higher than Finchbill,shows in that the neighbors in shorter distance.So,the Bulbul nesting site selection is taken more advantage to avoid parasitic risk than Finchbill.By the way,the Finchbill nest tend to close to human habitat as breeding season gose by.2.The egg recognizes ability and mechanism were studied by artificial model eggs.The result shows that the percentage of rejected non mimicry model eggs of Bulbul and Finchbill are 63.63%(n=66)and 100%(n=10),respectively.The ability of Finchbill is stronger than Bulbul's.Both of Bulbul and Finchbill rejecting alien eggs by true mechanism,but the mechanism of Bulbul is incompletion as the results of coevolution with its potential parasites.And the nest sanitation of Bulbul is makes no impact on its behavior of egg rejection.Bulbul also can't recognize its own eggs which had painting blue,black and fluorescence color,but Finchbill can rejected this painting eggs in the percentage of 66.67%(n=18),27.78%(n=18)and(45.45%(n=22),respectively.There is significant difference in the rejection of painted blue and fluorescence eggs of Finchbill,shows that Finchbill may be sensitive in the wave length of yellow and red.In the studies of cuckoo eggshell thickness,the result shows that the cuckoos in Kuankuoshui area had no evolved more strong eggshell.3.In the cross-fostering experiments,Bulbul and Finchbill can fed 23.53%(n=17)alien hosts nestling successful,but both of them were not discriminated the alien chicks,also did not show abnormal reaction to the single chick.Brown breasted Bulbul can't fed Large Hawk-Cuckoo nestlings successful by the reason of the fruit diet during nestling period.Bulbul should extend its nestling period base on the nestling growth situation,and does not abandon the chick when beyond its normal feeding period.And 88%(n=25)of hosts are consistency with its parasites in begging behavior,shows that the coevolution relationship of cuckoo and its hosts in Kuankuoshui reserve.4.We confirmed the strategy blocking hypothesis by testing the interaction between ability of discriminate of alien eggs and cuckoo adults dummies in Bulbul population.Our result shows that the ability of recognize of model eggs and cuckoo adults dummies is positive correlation(F1,64=9.27,P=0.003),the result does not support the strategy blocking hypothesis.Bulbul takes difference reaction to the cuckoo dummies in incubation and nestling period,it can recognized the cuckoo,besra and dove dummies in incubation period,but does not in nestling period.This result shows Bulbul could judge difference risk in difference brood period.We studied the interaction between egg recognize ability and flight initiation distance(FID)during Bulbul parent incubating on its nest,but the result shows that there is no remarkably correlative.In conclusion,this dissertation comparative analyses the difference of anti-parasitic stratagies of two sympatric Pycnonotidae species which under the same parasitic press.And we did research into many adaptive characters of them,including nest site selection,egg recognition,chick rejection and so on.We also first performance the strategy blocking is inexistence in the Bulbul population basing on the relationship of nest defense and egg recognition.