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The National Invasive Ant Surveillance programme (NIAS) detects 10-12 exotic ants per year at Ports and targeted Transitional facilities (devanning sites). With each incursion, the origin of the exotic ants that were detected is unknown, and it is impossible to trace the incursion. Due to the fact that the ants move from the containers to a food source by the time of sampling, there is generally no association of the ants with specific containers. Understanding the relative origin of ant incursions would better inform the risk around surveillance sites and help with selecting transitional facilities for future surveillance. There are thousands of transitional facilities clustered throughout the country and ‘smart’ site selection is needed to target the risk associated with transitional facilities.
At present, risk variables such as first port of origin and volume of containers; commodity type; and sites of previous detections of ants or other insects are used to determine which transitional facilities are surveyed. There is no evidence however, that these variables are important for predicting where ant incursions may occur, and consequently whether they are important for site selection. It would be useful to know if these (and other) variables are key components for site selection, and to identify the etiology of ant arrivals to New Zealand to inform where ant surveillance can be targeted.
The main objective of this project is to develop a better understanding of the patterns of ant arrivals to New Zealand. The project aims to predict risk in relation to sites, and in particular transitional facilities, where ants are more likely to arrive. The development of such risk profiles will enable scientifically defensible rationale to select sites for targeted surveillance within the NIAS program.
The first year of the project has been spent collating and curating data in preparation for the second year, which is the modelling phase. An interim report was produced and provided to MPI (Veronica Herrera) at the end of May. This report included a network diagram describing possible ant pathways into New Zealand, as well as preliminary analysis of some of the datasets collected. The preliminary analysis suggested that the data collected could be used to describe the changing patterns of ant arrivals into New Zealand over time.
Author(s): Stephen E. Lane and Lora Peacock
Published: May 5, 2020
Date added: December 23, 2021