Female Blow Flies As Vertebrate Resource Indicators

Charity G Owings,Christine J Picard,William P Gilhooly,Mary Huffine,Iyun M Adebowale,Nicholas E Manicke,Travis M D Asher,Anais Tuceryan,Christine L Skaggs,Aniruddha Banerjee

doi:10.1038/s41598-019-46758-9

Abstract

Rapid vertebrate diversity evaluation is invaluable for monitoring changing ecosystems worldwide. Wild blow flies naturally recover DNA and chemical signatures from animal carcasses and feces. We demonstrate the power of blow flies as biodiversity monitors through sampling of flies in three environments with varying human influences: Indianapolis, IN and two national parks (the Great Smoky Mountains and Yellowstone). Dissected fly guts underwent vertebrate DNA sequencing (12S and 16S rRNA genes) and fecal metabolite screening. Integrated Nested Laplace Approximation (INLA) was used to determine the most important abiotic factor influencing fly-derived vertebrate richness. In 720 min total sampling time, 28 vertebrate species were identified, with 42% of flies containing vertebrate resources: 23% DNA, 5% feces, and 14% contained both. The species of blow fly used was not important for vertebrate DNA recovery, however the use of female flies versus male flies directly influenced DNA detection. Temperature was statistically relevant across environments in maximizing vertebrate detection (mean = 0.098, sd = 0.048). This method will empower ecologists to test vertebrate community ecology theories previously out of reach due practical challenges associated with traditional sampling.

Highlights

Biodiversity is integral to ecosystem health and stability, and the loss thereof can have dramatic and cascading consequences on a global scale[1,2,3]
As host DNA can be recovered from epithelial cells found on the exterior surface of feces[18], flies can pick up vertebrate DNA in addition to fecal metabolites when feeding on this type of resource
ANOVA revealed a significant difference among the sexes of flies sampled for vertebrate DNA (P = 0.043), with a post-hoc test showing that female P. regina detected significantly more vertebrate species than males (P = 0.038, Fig. 1). 33% of female P. regina tested positive for vertebrate DNA, compared to 21% and 14% in male P. regina and blow flies of other species, respectively

Summary

Introduction

Biodiversity is integral to ecosystem health and stability, and the loss thereof can have dramatic and cascading consequences on a global scale[1,2,3]. Camera trapping requires sensitive image processing, large data capacities, and may carry a body-size bias[8,9,10] Such methods limit the number of taxa or guilds that can be evaluated simultaneously, requiring implementation of several methods (increasing sampling effort and cost) for total community assessment. The black blow fly Phormia regina (Meigen, Diptera: Calliphoridae) was the primary blow fly species of interest in this study This species is highly abundant and one of the most forensically important blow flies in the United States[21,22].

Objectives

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Results

Conclusion