Skip to main content
ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Crop and Commodity Protection Research » Research » Publications at this Location » Publication #413592
Research Project: Development of New and Improved Surveillance, Detection, Control, and Management Technologies for Fruit Flies and Invasive Pests of Tropical and Subtropical Crops

Location: Tropical Crop and Commodity Protection Research

Title: Understanding the movement and dispersal patterns of released Fopius arisanus (Hymenoptera: Braconidae) parasitoids in a papaya orchard

Author
item EITAM, AVRAHAM - Animal And Plant Health Inspection Service (APHIS)
item Stockton, Dara
item Vargas, Roger

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2024
Publication Date: 4/18/2024
Citation: Eitam, A., Stockton, D.G., Vargas, R.I. 2024. Understanding the movement and dispersal patterns of released Fopius arisanus (Hymenoptera: Braconidae) parasitoids in a papaya orchard. Environmental Entomology. https://doi.org/10.1093/ee/nvae029.
DOI: https://doi.org/10.1093/ee/nvae029

Interpretive Summary: Fruit flies in Hawaii and other pacific island nations have traditionally been managed using augmentative biological control releases of small parasitic wasps. This study investigated the dispersal parameters of one parasitoid species, Fopius arisanus, on the big island of Hawaii during 2006. The study found that recurrent releases at least weekly, spaced within 30 m, were required to achieve optimal control of fruit fly pests. Both parasitism and trap captures were in agreement that parasitoid numbers were extremely low after only 1 week and greater than 30 m from the release point. This suggests that single releases that do not spread the parasitoids over large distances may be ineffective at managing fruit fly incursions, since parasitoid movement itself is limited. The study did show that wind direction can affect dispersal, and also found a positive relationship between barometric pressure and parasitism rates, factors that can help inform the implementation of future augmentative releases.

Technical Abstract: Implementation of augmentative biological control requires estimates of parasitoid dispersal from the release point, in order to determine the appropriate release density, spacing, and timing of releases. This study evaluated the movement patterns of mass-reared parasitoids (F. arisanus) after release in a papaya orchard near Kalapana, HI. The wasps were released from central point and dispersal was monitored over time using parasitism in sentinel fruit and trap captures at 40 points radiating out from the center (15-240 m). The releases were conducted four times during Jun, July, Sept, and Nov 2006. The data showed that there were large declines in dispersal of the wasps by distance with the greatest percent parasitism occurring closest to the release point, within 30 m. Parasitism was also greatest within the first 24 h of the release. After 1 week, parasitism decreased from 46% to less than 1% at 15 m. Males were captured in greater numbers than females in our sticky sphere traps, and the number of trap captures was greatest in the SE, S, and SW regions of our trapping location. This corresponds to the prevailing wind direction in that location, but we also found that temperature and atmospheric pressure were associated with differences in dispersal, with negative and positive correlations, respectively. This is the first report of dispersal metrics for F. arisanus.