Does the niche breadth or trade‐off hypothesis explain the abundance–occupancy relationship in avian Haemosporidia?

Abstract

Two hypotheses have been proposed to explain the abundance-occupancy relationship (AOR) in parasites. The niche breadth hypothesis suggests that host generalists are more abundant and efficient at colonizing different host communities than specialists. The trade-off hypothesis argues that host specialists achieve high density across their hosts' ranges, whereas generalists incur the high cost of adaptation to diverse immuno-defence systems. We tested these hypotheses using 386 haemosporidian cytochrome-b lineages (1894 sequences) recovered from 2318 birds of 103 species sampled in NW Africa, NW Iberia, W Greater Caucasus and Transcaucasia. The number of regions occupied by lineages was associated with their frequency suggesting the presence of AOR in avian Haemosporidia. However, neither hypothesis provided a better explanation for the AOR. Although the host generalist Plasmodium SGS1 was over three times more abundant than other widespread lineages, both host specialists and generalists were successful in colonizing all study regions and achieved high overall prevalence.

Integrating coalescent species delimitation with analysis of host specificity reveals extensive cryptic diversity despite minimal mitochondrial divergence in the malaria parasite genus Leucocytozoon

“…In particular, a “one base pair rule” whereby a single base pair difference in the cytb barcoding fragment indicates reproductive isolation has become a popular means with which to delimit species in macroecological studies of haemosporidian diversity [35, 36, 78] despite mixed support for the rule [22, 79, 80]. We recovered support for 21 species of Leucocytozoon despite studying 28 cytb haplotypes, several of which differed by a single base pair.…”

Differences in host species relationships and biogeographic influences produce contrasting patterns of prevalence, community composition and genetic structure in two genera of avian malaria parasites in southern Melanesia

“…Drovetski et al . () found examples of both strategies in haemosporidian lineages in continental Northern Hemisphere locations that share many host species. In southern Melanesia, parasites that infected more species did achieve relatively wider distributions; however, four of these lineages achieved these distributions by infecting Zosterops species only (VN3P, VN1Ha, NC2H and VN3H).…”

“…Moreover, differences in host specialization may influence the number of hosts that can be utilized by parasites and therefore shape prevalence and geographic range of a parasite (Hellgren, Pérez‐Tris & Bensch ; Drovetski et al . ; Medeiros, Ellis & Ricklefs ). To examine the factors that are important in determining parasite distributions and hence their potential impacts on hosts, a host community perspective is required, where a group of pathogens is examined across a suite of co‐occurring host species.…”

Age, but not sex and seasonality, influence Haemosporida prevalence in White-banded Tanagers (Neothraupis fasciata) from central Brazil

“…In addition, molecular studies of avian malaria parasite assemblages have changed the view that blood parasites are usually host specialists (Ricklefs et al 2005;Fecchio et al 2013;Svensson-Coelho et al 2013;Clark et al 2014). For example, not only can a bird species harbor multiple lineages of Plasmodium and Haemoproteus, but a single haemosporidian lineage is capable of infecting multiple host species across its geographic range (Valkiūnas 2005;Drovetski et al 2014). …”