Avian malaria,haematocrit,and body condition in invasive wetland passerines settled in southwestern Spain

Avian malaria and related haemosporidian parasites can negatively impact fitness in many songbirds.Research on the malaria infection and its physiological costs on their avian hosts is heavily skewed toward native passerines,with exotic species underrepresented.However,introduced species may carry on and spread new pathogens to native species,and play a role on parasite transmission cycle in invaded bird communities as pathogen reservoir.Here,we molecularly assess the prevalence and diversity of haemosporidian parasites in three introduced wetland passerines(the Red Avadavat Amandava amandava,the Yellow-crowned Bishop Euplectes afer,and the Common Waxbill Estrilda astrild)captured during the same season in southwestern Spain.We also explored the relation between parasite infection,body condition,haematocrit,and uropygial gland volume.We detected an overall parasite prevalence of 3.55%,where Common Waxbills showed higher prevalence(6.94%)than Red Avadavats(1.51%).None Yellow-crowned Bishops were infected with haemosporidians.Almost 60%of infections were caused by Leucocytozoon,and about 40%by Plasmodium.We identified four unique lineages of Plasmodium and three of Leucocytozoon.Moreover,91%of the identified host-parasite interactions represented new host records for these haemosporidian parasites.Parasite infection was not related to body condition,haematocrit,and uropygial gland volume of the wetland passerines.Haematocrit values varied seasonally among bird species.Additionally,haematocrit was positively related to body condition in the Yellow-crowned Bishops,but not in the other species.Red Avadavats had higher haematocrit levels than Yellow-crowned Bishops,whereas Common Waxbills showed the lower haematocrit values.The uropygial gland volume was positively correlated with body condition in all bird species.Common Waxbills showed higher uropygial gland volumes related to their body size than birds from other two species.These outcomes highlight the importance of exotic invasive species in the transmission dynamics of haemosporidian parasites.

Extra-pair paternity and antiparasitic defence

Background:Extra-pair paternity(EPP)in birds provides benefits in terms of more offspring,and characteristics for maintenance of this behaviour have been the subject of investigation.Microorganisms are known to be transmitted during mating,especially when mating with multiple partners,and factors reducing this cost of multiple mating are expected.Further,plumage brightness and colour intensity have been shown to be important traits to benefits from multiple mating as predicted by sexual selection.The aim of this study was to investigate the relationship between the rate of extra-pair paternity and the relative size of the uropygial gland at the interspecific level,as the uropygial gland is an exocrine gland hypothesized to produce antiparasitic substances and further identified to affect plumage brightness.Because of the expected benefits of large uropygial gland in scenarios of sexual selection,we predicted a positive correlation with EPP.Methods:We collected information from the literature of uropygial gland size and frequency of extra-pair paternity of 60 avian species of different families and explored the predicted positive correlation between them.We did so with means of comparative analyses that considered phylogenetic relationship as random factor and included body mass as covariate.We used Markov chain Monte Carlo generalized linear mixed models that were weighted by number of nests used to estimate extra-pair paternity.Results:We detected a positive relationship between level of extra-pair paternity and uropygial gland size at an interspecific level.This finding is consistent with the prediction.Conclusions:We discuss the importance of this result in scenarios of sexual selection and argue that the detected relationship may have arisen by utilizing antiparasitic secretions through secondary sexual characters indicating parasite resistance.