# Establishing the distribution of Carpophilus truncatus in Australia using an integrative approach for an emerging global pest

## TL;DR

This study tracks the spread of a harmful beetle in Australia using historical data, fieldwork, and modeling to better manage its impact on crops.

## Contribution

The study introduces an integrative approach combining historical records, field trapping, thermal trials, and modeling to map pest distribution.

## Key findings

- Carpophilus truncatus is more widespread in Australia than previously known.
- Historical records show the beetle's presence in Australia predates commercial almond farming by a century.
- The study's methods can be used globally for emerging pests in a changing climate.

## Abstract

The nitidulid beetle Carpophilus truncatus is rapidly becoming a major pest of nut crops around the world. This insect first infested Australian almonds in 2013 and has since escalated to be the preeminent insect pest for the industry. Data pertaining to C. truncatus distribution are scant, but without awareness of its origin, distribution, and ecological factors that influence distribution, efforts to understand and manage the insect as a pest are stymied. Here, we employ an integrative approach to gain a multifaceted understanding of the distribution of C. truncatus in Australia. Methods employed were (1) reviewing historical records in insect collections to establish the presence of C. truncatus prior to commercial almond horticulture, (2) field trapping of insects to establish presence in regions of interest, (3) laboratory trials to determine the thermal limits of the organism, and (4) correlative species distribution modelling to describe its current distribution. We find that C. truncatus is more widespread across Australia than was previously known, with historical records preceding commercial almond production in Australia by a century. The methods developed in this study can be applied elsewhere in the world where C. truncatus is an emerging pest, or to novel pest species as they arise with increasing frequency in a globalised and warming world.