Feeding habits, movement, and reproduction of the predatory flat bark beetles Cathartus quadricollis 1 (Coleoptera: Silvanidae) and Leptophloeus sp. (Coleoptera: Laemophloeidae) in Hawaii coffee and 2 macadamia nut

Authors: BRILL EVA - University Of Hawaii; Follett, Peter; KAWABATA, ANDREA - University Of Hawaii

Submitted to: International Journal of Tropical Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2020
Publication Date: 7/13/2020
Citation: Brill Eva, Follett, P.A., Kawabata, A. 2020. Feeding habits, movement, and reproduction of the predatory flat bark beetles Cathartus quadricollis 1 (Coleoptera: Silvanidae) and Leptophloeus sp. (Coleoptera: Laemophloeidae) in Hawaii coffee and 2 macadamia nut. International Journal of Tropical Insect Science. 41:285-294. https://doi.org/10.1007/s42690-020-00205-9.
DOI: https://doi.org/10.1007/s42690-020-00205-9

Interpretive Summary: Flat bark beetles are predators of coffee berry borer (CBB) and other scolytine pests in Hawaii coffee and macadamia nut. Molecular analysis of two flat bark beetles Cathartus quadricollis and Leptophloeus sp. collected from coffee and macadamia nut farms showed they had fed on coffee berry borer, tropical nut borer and black twig borer. Cathartus quadricollis raised and released for augmentative biocontrol of CBB were recaptured at 1, 2 and 7 weeks post-release indicating that they remained where close to the release site. Predation on CBB eggs placed in artificial coffee berries averaged 40% after 48 hours. Flat bark beetle predators are natural enemies of several significant agricultural scolytine pests in Hawaii and have excellent potential for biological control with augmentative releases.

Technical Abstract: Hawaii has a multitude of scolytine (Coleoptera: Curculionidae: Scolitinae) pests including Hypothenemus hampei, coffee berry borer, which is a coffee pest of coffee, Hypothenemus obscurus, tropical nut borer, a significant pest of macadamia nut, and Xylosandrus compactus, black twig borer, a pest of many tropical and ornamental crops. The flat bark beetles, Carthartus quadricollis (Coleoptera: Silvanidae) and Leptophloeus sp. (Coleoptera; Laemophloeidae), are known to predate on coffee berry borer and tropical nut borer but their natural history (feeding habits, reproduction and movement) are poorly understood. Studies were conducted using molecular, field, and laboratory assays to examine 1) flat bark beetle reproduction and movement in coffee and the broader agricultural landscape, 2) establishment of augmentative releases for biological control, and 3) predation rates on H. hampei, H. obscurus and X. compactus. Various life stages of C. quadricollis and Leptophloeus sp. were found in seven different plant species common to the agricultural landscape around coffee farms, suggesting these predators are feeding and reproducing on theses hosts. Molecular analysis indicated that C. quadricollis and Leptophloeus sp. predated on H. hampei, H. obscurus and X. compactus in coffee, macadamia nut, and mixed coffee-macadamia nut farms. Laboratory reared predators were recaptured near release sites on coffee farms at 1, 2, and 7 weeks after augmentative releases. Predation of C. quadricollis on H. hampei eggs placed inside artificial coffee berries in coffee farms was about 40%. Predators C. quadricollis and Leptophloeus sp. are natural enemies of some significant agricultural scolytine pests in Hawaii and have excellent potential for biological control with augmentative releases.