Genetic evidence links invasive monk parakeet populations in the United States to the international pet trade

Timothy F Wright,Michael A Russello,Michael L Avery

doi:10.1186/1471-2148-8-217

Abstract

BackgroundSevere ecological and economic impacts caused by some invasive species make it imperative to understand the attributes that permit them to spread. A notorious crop pest across its native range in South America, the monk parakeet (Myiopsitta monachus) has become established on four other continents, including growing populations in the United States. As a critical first step to studying mechanisms of invasion success in this species, here we elucidated the geographical and taxonomic history of the North American invasions of the monk parakeet. Specifically, we conducted a genetic assessment of current monk parakeet taxonomy based on mitochondrial DNA control region sequences from 73 museum specimens. These data supported comparative analyses of mtDNA lineage diversity in the native and naturalized ranges of the monk parakeet and allowed for identification of putative source populations.ResultsThere was no molecular character support for the M. m. calita, M. m. cotorra, and M. m. monachus subspecies, while the Bolivian M. m. luchsi was monophyletic and diagnosably distinct. Three haplotypes sampled in the native range were detected within invasive populations in Florida, Connecticut, New Jersey and Rhode Island, the two most common of which were unique to M. m. monachus samples from eastern Argentina and bordering areas in Brazil and Uruguay.ConclusionThe lack of discrete morphological character differences in tandem with the results presented here suggest that M. m. calita, M. m. cotorra and M. m. monachus are in need of formal taxonomic revision. The genetic distinctiveness of M. m. luchsi is consistent with previous recommendations of allospecies status for this taxon. The geographic origins of haplotypes sampled in the four U.S. populations are concordant with trapping records from the mid-20th century and suggest that propagule pressure exerted by the international pet bird trade contributed to the establishment of invasive populations in the United States.

Highlights

Severe ecological and economic impacts caused by some invasive species make it imperative to understand the attributes that permit them to spread
As the accuracy of monk parakeet taxonomy has been questioned, we initially conducted a genetic assessment of the biological validity of the four currently recognized subspecies of M. monachus by way of historical DNA analysis from museum specimens collected throughout the native range. This broad sampling of mitochondrial DNA lineage diversity in the endemic range provides a reference database by which to infer the origin and extent of Sampling Toepad tissue was obtained from 73 museum specimens of Myiopsitta monachus representing all four subspecies (M. m. calita, n = 9; M. m. cotorra, n = 16; M. m. luchsi, n = 14; M. m. monachus, n = 38) courtesy of the American Museum of Natural History (AMNH)
Within subspecies variation A total of 17 mitochondrial DNA (mtDNA) control region (CR) haplotypes were recovered among the 77 individuals sampled from across the native range of the four described subspecies of M. monachus (GenBank Accession No EU545521-EU545537)

Summary

Introduction

Severe ecological and economic impacts caused by some invasive species make it imperative to understand the attributes that permit them to spread. We conducted a genetic assessment of current monk parakeet taxonomy based on mitochondrial DNA control region sequences from 73 museum specimens. These data supported comparative analyses of mtDNA lineage diversity in the native and naturalized ranges of the monk parakeet and allowed for identification of putative source populations. The severe ecological and economic impacts of invasive species render it imperative to understand the attributes that permit them to establish and spread within their expanded ranges. The monk parakeet (Myiopsitta monachus) is one of the most successful parrot invaders [4] It has been historically regarded as an agricultural pest in its native range in South America, as noted by Charles Darwin during his voyage on the H.M.S. Beagle:

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