Infiltration by alien predators into invertebrate food webs in Hawaii: a molecular approach.

Area of Science:

• Ecology
• Conservation Biology
• Molecular Biology

Background:

• Alien invertebrate predators are introduced to Hawaii for pest control, primarily in agricultural lowlands.
• Assessing their impact on native food webs in pristine upland areas is crucial for conservation.
• Endemic Lepidoptera species, such as Scotorythra and Eupithecia, are of significant conservation concern.

Purpose of the Study:

• To develop and validate molecular techniques for assessing the dietary impact of alien predators on native Hawaiian Lepidoptera.
• To quantify predator-prey interactions within native food webs in upland ecosystems.
• To establish a framework for using molecular gut analysis in arthropod conservation.

Main Methods:

• Field surveys to assess alien predator densities in the Alakai Swamp, Kaua'i.
• Laboratory experiments using endemic Lepidoptera (Scotorythra, Eupithecia) and alien predators (Halmus chalybeus, Curinus coeruleus).
• Development of prey-specific Polymerase Chain Reaction (PCR) primers targeting mitochondrial DNA (COI gene) for detecting Lepidoptera DNA in predator guts.

Main Results:

• Alien predators, including Halmus chalybeus and Curinus coeruleus, were found in upland areas.
• Successful detection of Lepidoptera DNA in the guts of alien predators up to 24 hours after feeding.
• Developed species-specific PCR primers capable of identifying specific endemic Lepidoptera genera and species.

Conclusions:

• Molecular gut analysis is a viable and effective tool for monitoring alien predator diets and their impact on native arthropods.
• This methodology provides a robust framework for future arthropod conservation ecology and food web research in Hawaii and globally.
• Quantifying these interactions is essential for understanding and mitigating threats to endemic species.