Oviposition biology, behavior, and avocado cultivar preferences of Heilipus lauri Boheman (Coleoptera: Curculionidae).

Abstract

Heilipus lauri is a specialist avocado seed feeding weevil native to parts of México and is an invasive pest in Colombia. This weevil is considered an incursion risk because possible unintended introductions into areas outside of its native range can result in establishment, which threatens avocado production in invaded regions. Despite being a well-recognized pest of avocados, relatively little is known about oviposition biology, behavior, and cultivar preferences of this weevil. Field studies in commercial Hass avocado orchards in México and laboratory studies in a quarantine facility in California (USA) indicated that H. lauri prefers to oviposit into middle and bottom thirds of fruit. In the laboratory, an average of 1.7 eggs (range 1-6 eggs) are laid over a 24-h period in oviposition chambers by individual females. Conspecifics add eggs to these clutches, with up to 17 eggs being recorded in 1 oviposition chamber. This finding suggests that H. lauri does not use an oviposition deterring pheromone. Female weevils readily oviposit in artificial holes representing mechanical wounds on fruit. In comparison to the commercially dominant Hass variety, fruit from Lamb Hass and G22, a native Guatemalan variety, and to a lesser extent Gem, may be less preferred for oviposition when females have a choice of fruit in which to oviposit. Videography studies indicated that H. lauri exhibits predominantly diurnal activity with respect to oviposition behaviors, feeding, and walking.