Mosquito Communities and Avian Malaria Prevalence in Silvereyes (Zosterops lateralis) Within Forest Edge and Interior Habitats in a New Zealand Regional Park

Abstract

Forest fragmentation and agricultural development are important anthropogenic landscape alterations affecting the disease dynamics of malarial parasites (Plasmodium spp.), largely through their effects on vector communities. We compared vector abundance and species composition at two forest edge sites abutting pastureland and two forest interior sites in New Zealand, while simultaneously assessing avian malaria prevalence in silvereyes (Zosterops lateralis). Twenty-two of 240 (9.2%) individual silvereyes captured across all sites tested positive for avian malaria, and Plasmodium prevalence was nearly identical in edge and interior habitats. A total of 580 mosquito specimens were trapped across all sites. These comprised five different species: the introduced Aedes notoscriptus and Culex quinquefasciatus; the native A. antipodeus, C. asteliae and C.pervigilans. The known avian malaria vector C. quinquefasciatus was only recorded in the forest edge (mostly at ground level). In contrast, the probable vector C. pervigilans was abundant and widespread in both edge and interior sites. Although frequently caught in ground traps, more C. pervigilans specimens were captured in the canopy. This study shows that avian malaria prevalence among silvereyes appeared to be unaffected by forest fragmentation, at least at the scale assessed. Introduced mosquito species were almost completely absent from the forest interior, and thus our study provides further circumstantial evidence that native mosquito species (in particular C. pervigilans) play an important role in avian malaria transmission in New Zealand.

Correlates of blood parasitism in a threatened marshland passerine: infection by kinetoplastids of the genus Trypanosoma is related to landscape metrics of habitat edge

“…Core area of habitat (positively) and edge density (negatively) were found to be related to bird abundance in a grassland passerine (Herse et al ., 2018). Within-species research on blood parasite infection in relation to habitat edge and fragmentation all concerned forest habitats and showed negative (Pérez-Rodríguez et al ., 2018), positive (Laurance et al ., 2013) or no associations (Sebaio et al ., 2010; Gudex-Cross et al ., 2015). This area clearly requires more research, especially in birds of open habitats.…”

“…Also, habitat fragmentation and heterogeneity are expected to affect parasite infection in birds, through increased edge effects and the introduction of new parasite lineages by species occupying ecotones and areas between fragments (Loye and Carroll, 1995; Holmes, 1996). However, studies that addressed the relationship between habitat fragmentation/edge and blood parasite infection in birds are scarce, focused solely on forest habitats and only two of them involved intraspecific comparisons (Sebaio et al ., 2010; Laurance et al ., 2013; Gudex-Cross et al ., 2015; Pérez-Rodríguez et al ., 2018). For example, in a forest passerine, the Antillean Bullfinch ( Loxigilla noctis ), prevalence of two hemosporidian lineages is positively related to variables describing habitat fragmentation and amount of edge (Pérez-Rodríguez et al ., 2018).…”

Manifold habitat effects on the prevalence and diversity of avian blood parasites

“…A recent study in New Zealand documented mosquito diversity and avian malaria prevalence at forest interior and forest edge sites. Although malaria prevalence in silvereyes ( Zosterops lateralis ) did not differ significantly among the sites, the authors found that introduced mosquitoes ( C. quinquefasciatus ) were not found in the forest interiors, but native mosquitoes were found in both habitats ( Gudex-Cross et al., 2015 ). More work is needed in this system to ascertain the vector responsible for transmission, but the results are an important step in examining the distributions of disease vectors with regard to deforestation.…”

Habitat fragmentation, not habitat loss, drives the prevalence of blood parasites in a Caribbean passerine

“…The main vectors of the two considered parasite genera differ: Plasmodium spp. Although several studies have analyzed how avian haemosporidian richness and prevalence (that is, the number of different parasites, and the proportion of infected hosts, per locality) are linked to a number of forest traits, either directly (Chasar et al 2009, Laurance et al 2013, Hernández-Lara et al 2017 or through the study of their vectors (Reiter and LaPointe 2007, Abella-Medrano et al 2015, Gudex-Cross et al 2015, studies on how habitat loss and fragmentation may determine their natural dynamics are scarce and offer inconclusive results (Sebaio et al 2010, references reviewed in Sehgal 2015, Ferreira et al 2017). (Santiago-Alarcon et al 2012).…”

“…These parasites have been extensively studied both because they are an effective study model of human malaria (Garamszegi 2011), and for their own deleterious effects on birds, which include negative effects on individual survival (Martínez-de la Puente et al 2010, Krams et al 2013 and reproduction (Marzal et al 2005, Knowles et al 2010, pathogenic outbreaks among captive birds (Olias et al 2011, Scaglione et al 2016, and extinction of endemic insular species following the accidental introduction of exotic parasites (Samuel et al 2015). Although several studies have analyzed how avian haemosporidian richness and prevalence (that is, the number of different parasites, and the proportion of infected hosts, per locality) are linked to a number of forest traits, either directly (Chasar et al 2009, Laurance et al 2013, Hernández-Lara et al 2017 or through the study of their vectors (Reiter and LaPointe 2007, Abella-Medrano et al 2015, Gudex-Cross et al 2015, studies on how habitat loss and fragmentation may determine their natural dynamics are scarce and offer inconclusive results (Sebaio et al 2010, references reviewed in Sehgal 2015, Ferreira et al 2017). In addition, and to the best of our knowledge, they all rely only on comparisons between disturbed/undisturbed sampling localities, lacking from accurate descriptions of the processes linked to habitat fragmentation.…”