Contrasting the seasonal and elevational prevalence of generalist avian haemosporidia in co‐occurring host species

Abstract

Understanding the ecology and evolution of parasites is contingent on identifying the selection pressures they face across their infection landscape. Such a task is made challenging by the fact that these pressures will likely vary across time and space, as a result of seasonal and geographical differences in host susceptibility or transmission opportunities. Avian haemosporidian blood parasites are capable of infecting multiple co‐occurring hosts within their ranges, yet whether their distribution across time and space varies similarly in their different host species remains unclear. Here, we applied a new PCR method to detect avian haemosporidia (genera Haemoproteus, Leucocytozoon, and Plasmodium) and to determine parasite prevalence in two closely related and co‐occurring host species, blue tits (Cyanistes caeruleus, N = 529) and great tits (Parus major, N = 443). Our samples were collected between autumn and spring, along an elevational gradient in the French Pyrenees and over a three‐year period. Most parasites were found to infect both host species, and while these generalist parasites displayed similar elevational patterns of prevalence in the two host species, this was not always the case for seasonal prevalence patterns. For example, Leucocytozoon group A parasites showed inverse seasonal prevalence when comparing between the two host species, being highest in winter and spring in blue tits but higher in autumn in great tits. While Plasmodium relictum prevalence was overall lower in spring relative to winter or autumn in both species, spring prevalence was also lower in blue tits than in great tits. Together, these results reveal how generalist parasites can exhibit host‐specific epidemiology, which is likely to complicate predictions of host–parasite co‐evolution.

A citizen science-based survey of avian mortality focusing on haemosporidian infections in wild passerine birds

“…The positive CISH results with the P. elongatum -specific probe detecting parasite stages in the tissues suggest that this parasite is able to develop in Paridae species. However, assuming that tits are susceptible to P. elongatum GRW06, it remains difficult to explain why P. elongatum GRW06 has been absent in free-living conspecifics sampled in other European localities, despite its prevalence in different sympatric passerines [ 65 – 67 ]. An experimental study showed that certain songbirds, specifically common starlings, are resistant to GRW06 infection [ 68 ].…”

Parasite detection and quantification in avian blood is dependent on storage medium and duration

“…Samples were screened for blood parasite infections at each time point (within 2 days of extraction) using a nested polymerase chain reaction (PCR) method specific to Plasmodium/Haemoproteus (Lynton-Jenkins et al, 2020). This method is a variation of wellestablished Haemosporidian PCR detection techniques (Bensch et al, 2000;Hellgren et al, 2004), implemented here due to the high prevalence of Leucocytozoon parasites in these study popu- Geneious (Geneious® 9.1.5, Kearse et al, 2012), and parasites were identified via BLAST on the MalAvi database (Bensch et al, 2009).…”

“…Beyond the choice of storage medium, an additional methodological consideration shared between all studies is the duration of sample storage prior to DNA extraction (Färnert et al, 1999 ; Permenter et al, 2015 ). This can vary vastly between studies, and yet storage duration prior to extraction typically goes unreported in sampling methodology (e.g., Knowles et al, 2011 ; Loiseau et al, 2013 ; Lynton‐Jenkins et al, 2020 ; van Rooyen et al, 2013 ). As a result, it is often unclear whether DNA was extracted rapidly after blood sampling or whether all extractions took place years later.…”

“…In this study, we used a within‐individual experimental design to explore the impact of storage medium and storage duration on Haemosporidia detectability by PCR and quantification by qPCR. We made use of a host population of Paridae that are known to harbor high prevalence of avian blood parasites belonging to the genera Haemoproteus and Plasmodium (Lynton‐Jenkins et al, 2020 ). We obtained blood samples across a short capture window and split each sample into identical aliquots stored in three different storage mediums to compare PCR and qPCR efficiency when applied to DNA extracts obtained at five time points: 1, 6 months, 1, 2, and 3 years post‐capture.…”

Phylogeographic Patterns of Haemoproteid Assemblages of Selected Avian Hosts: Ecological and Evolutionary Implications

“…The following supporting information can be downloaded at: , Table S1: CCA data; Table S2: PCA data; Table S3: Results of CCA and references to haemoproteid data compiled from the MalAvi database; Table S4: Results of PCA and references to haemoproteid data compiled from the MalAvi database. References [ 3 , 5 , 21 , 24 , 25 , 26 , 33 , 56 , 65 , 69 , 70 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 ] are cited in the supplementary materials.…”