Darwins finches combat introduced nest parasites with fumigated cotton

pre-printIntroduced parasites are a threat to biodiversity when naïve hosts lack effective defenses against such parasites [1]. Several parasites have recently colonized the Galápagos Islands, threatening native bird populations [2]. For example, the introduced parasitic nest fly Philornis downsi (Diptera: Muscidae) has been implicated in the decline of endangered species of Darwin's finches, such as the mangrove finch (Camarhynchus heliobates) [3]. Here, we show that Darwin's finches can be encouraged to "self-fumigate" nests with cotton fibers that have been treated with permethrin. Nests with permethrin-treated cotton had significantly fewer P. downsi than control nests, and nests containing at least one gram of cotton were virtually parasite-free. Nests directly fumigated with permethrin had fewer parasites and fledged more offspring than nests treated with water

Does avian malaria reduce fledging success: an experimental test of the selection hypothesis

pre-printLike many parasites, avian haematozoa are often found at lower infection intensities in older birds than young birds. One explanation, known as the "selection" hypothesis, is that infected young birds die before reaching adulthood, thus removing the highest infection intensities from the host population. We tested this hypothesis in the field by experimentally infecting nestling rock pigeons (Columba livia) with the malaria parasite Haemoproteus columbae. We compared the condition and fledging success of infected nestlings to that of uninfected controls. There was no significant difference in the body mass, fledging success, age at fledging, or post-fledging survival of experimental versus control birds. These results were unexpected, given that long-term studies of older pigeons have demonstrated chronic effects of H. columbae. We conclude that H. columbae has little impact on nestling pigeons, even when they are directly infected with the parasite. Our study provides no support for the selection hypothesis that older birds have lower parasite loads because parasites are removed from the population by infected nestlings dying. To our knowledge, this is the first study to test the impact of avian malaria using experimental inoculations under natural conditions

Winter Ecology of Buggy Creek Virus (Togaviridae, \u3ci\u3eAlphavirus\u3c/i\u3e) in the Central Great Plains

A largely unanswered question in the study of arboviruses is the extent to which virus can overwinter in adult vectors during the cold winter months and resume the transmission cycle in summer. Buggy Creek virus (BCRV; Togaviridae, Alphavirus) is an unusual arbovirus that is vectored primarily by the swallow bug (Hemiptera: Cimicidae: Oeciacus vicarius) and amplified by the ectoparasitic bug’s main avian hosts, the migratory cliff swallow (Petrochelidon pyrrhonota) and resident house sparrow (Passer domesticus). Bugs are sedentary and overwinter in the swallows’ mud nests. We evaluated the prevalence of BCRV and extent of infection in swallow bugs collected at different times in winter (October–early April) in Nebraska and explored other ecological aspects of this virus’s overwintering. BCRV was detected in 17% of bug pools sampled in winter. Virus prevalence in bugs in winter at a site was significantly correlated with virus prevalence at that site the previous summer, but winter prevalence did not predict BCRV prevalence there the following summer. Prevalence was higher in bugs taken from house sparrow nests in winter and (in April) at colony sites where sparrows had been present all winter. Virus detected by reverse transcription (RT)-polymerase chain reaction in winter was less cytopathic than in summer, but viral RNA concentrations of samples in winter were not significantly different from those in summer. Both of the BCRV lineages (A, B) overwintered successfully, with lineage A more common at sites with house sparrows and (in contrast to summer) generally more prevalent in winter than lineage B. BCRV’s ability to overwinter in its adult vector probably reflects its adaptation to the sedentary, long-lived bug and the ecology of the cliff swallow and swallow bug host–parasite system. Its overwintering mechanisms may provide insight into those of other alphaviruses of public health significance for which such mechanisms are poorly known

Winter Ecology of Buggy Creek Virus (Togaviridae, \u3ci\u3eAlphavirus\u3c/i\u3e) in the Central Great Plains

A largely unanswered question in the study of arboviruses is the extent to which virus can overwinter in adult vectors during the cold winter months and resume the transmission cycle in summer. Buggy Creek virus (BCRV; Togaviridae, Alphavirus) is an unusual arbovirus that is vectored primarily by the swallow bug (Hemiptera: Cimicidae: Oeciacus vicarius) and amplified by the ectoparasitic bug’s main avian hosts, the migratory cliff swallow (Petrochelidon pyrrhonota) and resident house sparrow (Passer domesticus). Bugs are sedentary and overwinter in the swallows’ mud nests. We evaluated the prevalence of BCRV and extent of infection in swallow bugs collected at different times in winter (October–early April) in Nebraska and explored other ecological aspects of this virus’s overwintering. BCRV was detected in 17% of bug pools sampled in winter. Virus prevalence in bugs in winter at a site was significantly correlated with virus prevalence at that site the previous summer, but winter prevalence did not predict BCRV prevalence there the following summer. Prevalence was higher in bugs taken from house sparrow nests in winter and (in April) at colony sites where sparrows had been present all winter. Virus detected by reverse transcription (RT)-polymerase chain reaction in winter was less cytopathic than in summer, but viral RNA concentrations of samples in winter were not significantly different from those in summer. Both of the BCRV lineages (A, B) overwintered successfully, with lineage A more common at sites with house sparrows and (in contrast to summer) generally more prevalent in winter than lineage B. BCRV’s ability to overwinter in its adult vector probably reflects its adaptation to the sedentary, long-lived bug and the ecology of the cliff swallow and swallow bug host–parasite system. Its overwintering mechanisms may provide insight into those of other alphaviruses of public health significance for which such mechanisms are poorly known

Global change drivers and the risk of infectious disease

Anthropogenic change is contributing to the rise in emerging infectious diseases, but it remains unclear which global change drivers most increase disease and under what contexts. We amassed a dataset from the literature that includes 1,832 observations of infectious disease responses to global change drivers across 1,202 host-parasite combinations. We found that biodiversity loss, climate change, and introduced species were associated with increases in disease-related endpoints or harm (i.e., enemy release for introduced species), whereas urbanization was associated with decreases in disease endpoints. Natural biodiversity gradients, deforestation, forest fragmentation, and most classes of chemical contaminants had non-significant effects on these endpoints. Overall, these results were consistent across human and non-human diseases. Context-dependent effects of the global change drivers on disease were common and are discussed. These findings will help better target disease management and surveillance efforts towards global change drivers that increase disease.One-Sentence SummaryHere we quantify which global change drivers increase infectious diseases the most to better target global disease management and surveillance efforts

Ectoparasite Abundance and Individual Color Variation in Three Cardueline Finch Species

Advisor: Muir EatonElaborate and/or colorful bird plumages have often been hypothesized to evolve via sexual selection for increased ornamentation. Differences in coloration among individuals can be influenced by a number of variables, including diet, hormones, and disease resistance. Specifically, Hamilton and Zuk 22 (1892) hypothesized a link between an individual’s parasite resistance and more colorful plumage signals, as a mechanism for individuals to advertise their ‘quality’. While much data has accumulated documenting the nutritional and hormonal regulation of various types of plumage coloration, relatively little data exists reporting the effects of parasite load on individual plumage colors (i.e. melanin and carotenoid pigmented feathers). We collected ectoparasites and plumage color data from 24 purple finches (Carpodacus purpureus), 11 pine siskins (Carduelis pinus), and 21 American goldfinches (Carduelis tristis). We found substantial individual variation in both total parasite load and quantified measures of feather coloration, and we report on the association between these variables among individuals within each species.Drake University, Department of Biolog

Data from: An introduced parasitic fly may lead to local extinction of Darwin's finch populations

Introduced pathogens and other parasites are often implicated in host population-level declines and extinctions. However, such claims are rarely supported by rigorous real-time data. Indeed, the threat of introduced parasites often goes unnoticed until after host populations have declined severely. The recent introduction of the parasitic nest fly, Philornis downsi, to the Galápagos Islands provides an opportunity to monitor the current impact of an invasive parasite on endemic land bird populations, including Darwin's finches. In this paper, we present a population viability model to explore the potential long-term effect of P. downsi on Darwin's finch populations. The goal of our study was to determine whether P. downsi has the potential to drive host populations to extinction and whether management efforts are likely to be effective. Our model is based on data from five years of experimental field work documenting the effect of P. downsi on the reproductive success of medium ground finch Geospiza fortis populations on Santa Cruz Island. Under two of the three scenarios tested, the model predicted medium ground finches are at risk of extinction within the next century. However, sensitivity analyses reveal that even a modest reduction in the prevalence of the parasite could improve the stability of finch populations. We discuss the practicality of several management options aimed at achieving this goal. Synthesis and applications. Our study demonstrates the predicted high risk of local extinction of an abundant host species, the medium ground finch G. fortis due to an introduced parasite, P. downsi. However, our study further suggests that careful management practices aimed at reducing parasite prevalence have the potential to significantly lower the risk of host species extinction

DeSimone et al dataset 2014-2016 grouped by nest

These are data on tree swallows and their associated blowfly parasites, in which each row represents one nest. One sheet includes the data, the other sheet includes the descriptions of variables

Description of Brachymeria philornisae sp. n. (Hymenoptera: Chalcididae), a parasitoid of the bird parasite Philornis trinitensis (Diptera: Muscidae) in Tobago, with a review of the sibling species

International audienceIn this paper, we describe and illustrate a new species of parasitoid wasp as Brachymeria philornisae Delvare, sp. nov. The new species was reared from Philornis trinitensis Dodge & Aitken (Diptera: Muscidae) puparia that were found in the nests of the bird species Mimus gilvus (Vieillot) (Mimidae) and Tiaris bicolor (L.) (Thraupidae) in Tobago. The new species is of particular interest as it may be considered a potential biological control agent in locations where Philornis species are invasive, such as the Galapagos Islands. Closely related Brachymeria species had taxonomically ambiguous relationship in the past and are compared and reviewed. The species have been classified in the subgenus Pseudobrachymeria, but are here treated within the newly defined subconica species-group of Brachymeria as part of a sibling species complex designated as the subrugosa complex. Species assigned to the subconica species-group are listed and five, one unnamed, are assigned to the subrugosa complex and their females keyed. Species are separated by qualitative characters and morphometry using distance measurements. Trigonura annulipes Costa Lima is renamed as Brachymeria costalimai Delvare nom. nov. because of secondary homonymy