Ecosystem-scale distribution and phenology of Gonipterini weevils associated with Eucalyptus populnea in Central Queensland, Australia

The Gonipterini tribe (Coleoptera: Curculionidae) contains a number of species of economic significance, including several species of Gonipterus which are invasive pests of eucalypt plantations internationally. However, the inter-specific ecosystem-level interactions and population dynamics of many species are poorly understood within their native range. This study investigated the associations of two species of Oxyops and two species of Gonipterus from Central Queensland, Australia, including their phenology over the course of a year-long survey. A total of 102 Gonipterini weevils were found, with Oxyops fasciculatus being the most abundant. Weevils were only found in 12.1% of the Eucalyptus populnea saplings surveyed; however, saplings containing weevils contained an average of 1.8 weevils. Additionally, 19.6% of weevils were found in close proximity to another weevil at a micro-ecosystem scale (e.g., on the same leaf). Weevil numbers peaked in March at 17.2 adults/acre, with the lowest numbers found in June (3.6 adults/acre). One of the Oxyops species (an undescribed species known only from Central Queensland) was more commonly found on the leaves, compared to Gonipterus cinnamomeus which was more commonly located on the stem or petiole. These results provide insight into the population dynamics, interactions, and spatial and temporal resource partitioning between different Gonipterini species within their native range.