Trypanosomatids Detected in the Invasive Avian Parasite Philornis downsi (Diptera: Muscidae) in the Galapagos Islands.

Courtney L Pike,María Piedad Lincango,Patricia G Parker,Charlotte E Causton

doi:10.3390/insects11070422

Courtney L Pike, María Piedad Lincango + Show 2 more

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https://doi.org/10.3390/insects11070422

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Abstract

Alien insect species may present a multifaceted threat to ecosystems into which they are introduced. In addition to the direct damage they may cause, they may also bring novel diseases and parasites and/or have the capacity to vector microorganisms that are already established in the ecosystem and are causing harm. Damage caused by ectoparasitic larvae of the invasive fly, Philornis downsi (Dodge and Aitken) to nestlings of endemic birds in the Galapagos Islands is well documented, but nothing is known about whether this fly is itself associated with parasites or pathogens. In this study, diagnostic molecular methods indicated the presence of insect trypanosomatids in P. downsi; to our knowledge, this is the first record of insect trypanosomatids associated with Philornis species. Phylogenetic estimates and evolutionary distances indicate these species are most closely related to the Crithidia and Blastocrithidia genera, which are not currently reported in the Galapagos Islands. The prevalence of trypanosomatids indicates either P. downsi arrived with its own parasites or that it is a highly suitable host for trypanosomatids already found in the Galapagos Islands, or both. We recommend further studies to determine the origin of the trypanosomatid infections to better evaluate threats to endemic fauna of the Galapagos Islands.

Highlights

Worldwide, parasites and disease are recognized threats to wildlife health [1,2,3,4]
Our study provides the first evidence of infection of Philornis species with insect-specific trypanosomatids
Neither of the most closely genetically related genera detected in P. downsi, Crithidia and Blastocrithidia, have previously been reported in the Galapagos Islands

Summary

Introduction

Parasites and disease are recognized threats to wildlife health [1,2,3,4]. Philornis downsi (Dodge and Aitken), a known dipteran parasite of passerine birds in the Neotropics [12], was first recorded in the Galapagos Islands in the 1960s [13]. This fly has become invasive, successfully colonizing at least 15 islands in the Galapagos archipelago, bringing serious consequences to the native avian fauna due to the blood-feeding behavior of its ectoparasitic larvae [14,15,16]. While many studies have been conducted on the fly’s effects on birds e.g., [17,18], studies on its associations with

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