Kīpahulu Valley, Haleakalā National Park, Maui, Field and Lab-based eDNA Proof-of-concept Study for the Detection of Culex quinquefaciatus 2022-2025

A leading contributor to the decline of Hawaiian forest birds is avian malaria caused by the protozoan parasite Plasmodium relictum and that is transmitted by the Southern House Mosquito (Culex quinquefasciatus). For conservation purposes, landscape-scale mosquito control techniques are being considered to disrupt the malaria disease cycle in key Hawaiian forest bird habitats. The implementation of mosquito control strategies is predicated upon knowledge of mosquito distribution and breeding sites, which can be assessed through adult trapping and larval surveys. However, visual searches within aquatic habitats may miss the time-period following the emergence of adults from pupae, at which point seasonal abundance of mosquitoes may be at peak levels. Environmental DNA (eDNA) may be used as a non-invasive surveillance tool to complement traditional mosquito monitoring techniques, potentially providing a broader window of time to assess whether ephemeral water sources serve as mosquito breeding grounds despite the lack of visual confirmation of larvae. In this study two types of experiments, one field- and one lab-based, were conducted to evaluate the suitability of eDNA as a technique to detect Culex quinquefasciatus. For field evaluation, 195 water samples, including negative controls, were taken in the field from a variety of water sources in two primary locations, Delta and Palikea Camps, within native forests of Kīpahulu Valley, Haleakalā National Park, Maui, during 2022 and 2023. As proof in principle, sampled water sources included unoccupied pools in addition to those with visible mosquito larvae of two species, Culex quinquefasciatus and Aedes japonicus. The eDNA was collected from water sources using three different filtering techniques and filter types. Data describing the field sampling conditions included water body source dimensions, substrate type, depth at which water was filtered, volume of water filtered, water filter type, field larval observations, eDNA extraction method, and quantitative polymerase chain reaction (qPCR) amplification results for the Culex eDNA assay during 2023-2024. The qPCR assay was used on field collected water samples, field negative controls, and extraction blanks to test for the presence of Culex eDNA shed into natural water sources. The laboratory experiment data consists of quantitative PCR results derived from a targeted assay to detect the presence of Culex quinquefasciatus eDNA shed under controlled laboratory conditions. Water samples from the three replicate container systems were collected throughout the developmental life stages of Culex quinquefasciatus, from egg rafts to beyond adult emergence (n=40), negative control water samples taken alongside experiment samples (n=18), and blank samples as controls during the DNA extraction process (n=2).

[
  "010:12"
]

[
  "geospatial"
]