The invasive parasitic fly Philornis downsi is threatening Little Vermilion Flycatchers on the Galápagos Islands

Avian Conservation and Ecology

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Denis Mosquera¹  Birgit Fessl¹  Eileen Heyer¹  Celina Leuba¹  Erwin Nemeth³  Maria Lorena Rojas¹  Christian Sevilla⁴  Sabine Tebbich² 

[1] Charles Darwin Research Station, Charles Darwin Foundation;Department of Behavioural and Cognitive Biology, University of Vienna;BirdLife Austria;Galápagos National Park Directorate

关键词: alien species;    breeding ecology;    conservation;    decline;    experimental;    host-parasite interactions;    nest;   

DOI  :  10.5751/ACE-02040-170106

学科分类：口腔科学

来源: Resilience Alliance Publications

【 摘 要 】

Populations of several species of birds endemic to the Galápagos Islands have declined during recent decades, including endemic Little Vermilion Flycatchers (Pyrocephalus nanus). Understanding the reasons for the low breeding success of this species is a prerequisite for developing efficient conservation strategies. Studies of sympatric Darwin’s finches suggest two potential reasons: parasitism by the invasive parasitic fly Philornis downsi and extreme climatic events. We investigated the role of each in the breeding success of Little Vermilion Flycatchers during three breeding seasons in the agricultural zone of Isabela Island. We found that Little Vermilion Flycatchers were severely affected by P. downsi, depending on the time of breeding. Nest success was high early in the breeding season (60% were successful) when rates of P. downsi prevalence and intensity were low, but nest success was zero and all nests were infested later in the breeding season. Philornis downsi prevalence and intensity increased with increasing temperature. Both low and high levels of rainfall had a negative effect on nest survival. A parasite removal experiment using insecticide confirmed the detrimental effect of the invasive parasite; nests infested with P. downsi had significantly lower nest success than treated nests. Injection of insecticide into nest bases can be an efficient short-term way to increase the nesting success of Little Vermilion Flycatchers, but finding long-term measures to control the P. downsi population is of utmost importance.

【 授权许可】

CC BY