Temporal and spatial variation in sex-specific abundance of the avian vampire fly (Philornis downsi)

Lauren K Common,Petra Sumasgutner,Sonia Kleindorfer,Rachael Y Dudaniec,Diane Colombelli-Négrel,Shane C Sumasgutner

doi:10.1007/s00436-021-07350-1

Abstract

Understanding the range and behaviour of an invasive species is critical to identify key habitat areas to focus control efforts. Patterns of range use in parasites can differ temporally, across life stages and between sexes. The invasive avian vampire fly, Philornis downsi, spends the larval stage of its life within bird nests, feeding on developing nestlings and causing high levels of mortality and deformation. However, little is known of the ecology and behaviour of the non-parasitic adult fly life stage. Here, we document sex-specific temporal and spatial patterns of abundance of adult avian vampire flies during a single Darwin’s finch breeding season. We analyse fly trapping data collected across 7 weeks in the highlands (N = 405 flies) and lowlands (N = 12 flies) of Floreana Island (Galápagos). Lowland catches occurred later in the season, which supports the hypothesis that flies may migrate from the food-rich highlands to the food-poor lowlands once host breeding has commenced. Fly abundance was not correlated with host nesting density (oviposition site) but was correlated with distance to the agricultural zone (feeding site). We consistently caught more males closer to the agricultural zone and more females further away from the agricultural zone. These sex differences suggest that males may be defending or lekking at feeding sites in the agricultural zone for mating. This temporal and sex-specific habitat use of the avian vampire fly is relevant for developing targeted control methods and provides insight into the behavioural ecology of this introduced parasite on the Galápagos Archipelago.

Highlights

In an era of increasing human and animal global mobility, the proportion of invasive species is rapidly increasing, exacerbated by the effects of climate change, over-exploitation, pollution, and habitat fragmentation (Pelletier and Section Editor: Elizabeth Marie WarburtonColtman 2018)
Understanding sex-specific range use, key resources, and habitat use by populations is critical for developing effective control techniques for invasive species
We found significant differences in temporal patterns of abundance of the invasive avian vampire fly across the Darwin’s finch breeding season and two habitat types on Floreana Island

Summary

Introduction

In an era of increasing human and animal global mobility, the proportion of invasive species is rapidly increasing, exacerbated by the effects of climate change, over-exploitation, pollution, and habitat fragmentation (Pelletier and Section Editor: Elizabeth Marie WarburtonColtman 2018). A single species may occupy and utilise different areas within its range across seasons, life stages, and between sexes (Bierzychudek and Eckhart 1988; Maxwell et al 2019; Ruckstuhl and Neuhaus 2006). Understanding the distribution and behaviour of an introduced species is useful to identify seasonally or geospatially restricted habitat areas to focus control and management efforts (Escobar et al 2019; Mathieu-Bégné et al 2020; Raghavan et al 2019; Woodworth et al 2005). Studies have found selective spatial and temporal habitat use between the sexes (Papadopoulos et al 2003; Sciarretta et al 2018; Warburg and Yuval 1997; Wong and Jim 2018). Sexual conflict and sexual dimorphism have been shown to drive sex-specific distributions in arthropods (Foster and Soluk 2006; Romey and Wallace 2007; Stanley et al 2018).

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Conclusion