DNA metabarcoding reveals diet composition of invasive rats and mice in Hawaiian forests

Sara M.E. Gabrielson, Rebecca L. Mau, Erika Dittmar, J. Patrick Kelley, Corey E. Tarwater, Donald R. Drake, Jinelle H. Sperry, Jeffrey T. Foster

Research output: Contribution to journalArticlepeer-review

Abstract

Rodents are among the most widespread and problematic invasive animals on islands worldwide contributing to declining endemic island biota through predation and disruption of mutualisms. Identifying what rodents eat is critically important to understanding their effects on ecosystems. We used DNA metabarcoding to identify the diets of three invasive rodents in Hawaiian forests: house mouse (Mus musculus), black rat (Rattus rattus), and Pacific rat (Rattus exulans). These rodents primarily eat invertebrates and plants, but previous diet studies have provided only a limited understanding of the diet breadth by relying on morphological identification methods. We opportunistically collected fecal samples from rodents trapped at seven forest sites across Oʻahu, Hawaiʻi for two years. Plant and invertebrate diet items were identified from DNA extracted from fecal samples using rbcL and COI primers, respectively. Intact seeds were identified using a dissecting microscope to quantify potential contributions to seed dispersal. All rodent species ate primarily plants and invertebrates of introduced species. However, some native taxa of conservation importance were identified. Neither the rodent species nor the sites drove patterns of diet composition, suggesting that diet variation may be determined by opportunistic foraging or intraspecific variation. Black rat fecal samples contained intact seeds more frequently than house mouse samples, but surprisingly, when samples contained seeds, black rats and house mice both defecated hundreds of introduced seeds, likely contributing to seed dispersal. Conservation efforts targeting invasive rodent control should specifically include house mice and should monitor introduced prey items to prevent predation release of unwanted introduced species.

Original languageEnglish (US)
Pages (from-to)79-105
Number of pages27
JournalBiological Invasions
Volume26
Issue number1
DOIs
StatePublished - Jan 2024

Keywords

  • Hawaiian Islands
  • Invasion biology
  • Invasive rodents
  • Next-generation sequencing
  • Seed dispersal
  • Seed predation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology

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