Revolutionizing invasive alien species control using behavioural economics and animal cognition

Project Information

COGNITIVE CONTROL

Grant agreement ID: 948181

DOI

10.3030/948181

EC signature date 29 October 2020

Start date 1 April 2021

End date 31 March 2027

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 451 805,00

EU contribution

€ 1 451 805,00

Coordinated by

FREIE UNIVERSITAET BERLIN
Germany

Periodic Reporting for period 3 - COGNITIVE CONTROL (Revolutionizing invasive alien species control using behavioural economics and animal cognition)

Reporting period: 2024-04-01 to 2025-05-31

Summary of the context and overall objectives of the project

Invasive ants are economically damaging and ecologically devastating. They reduce agricultural output, drive out local insect species, and can even disrupt whole ecosystems. Unfortunately, controlling such invasive ants is very difficult, and most eradication attempts have failed. It is not quite clear why eradication is proving so difficult.
The main objective of this project is to understand why invasive ants are proving so hard to control, and developing novel angles of attack against them. Ideas include adding substances (like caffeine) to toxic baits, to make the ants return to them faster or more often, and thus collect more toxins. Other approaches include identifying how ants evade attack by toxic baits - for example, by learning that baits are poisonous after encountering other poisoned ants. Beginning in the laboratory, and moving into the field, we are developing new control approaches and testing them.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Main results acheived so far:

1) Demonstrating that the major invasive ant in Europe (the Argentine ant - Linepithema humile) is an excellent learner.
2) Testing a wide range of psychoactive substances on Argentine ants, to identify some which may improve bait efficacy. Ruling out several psychoactives.
3) Demonstrating that caffeine at specific concentrations improves Argentine ant navigation.
4) Demonstrating that ants begin to avoid odours associated with dead nestmates - perhaps explaining some control failure
5) Demonstrating that Argentine ants actively evade attack by toxicants, through abandonment of toxic food sources.
6) Developing a new, highly sensitive assay for quantifying food preference in ants.
7) Developing a new, highly sensitive assay for quantifying food consumption in small insects such as ants.
8) Uncovering a systematic tolerance to bitter substances in invasive ants.
9) Demonstrating that invasive ants actively abandon toxic baits, through an as-yet unknown mechanism

Further work underway
Work is continuing on understanding the effect of adding toxicants or protein to food sources, on food dissemination patterns in the nest.
Work is continuing on understanding how plants may manipulate pollinators using psychological and behavioural economic techniques.
Work is continuing on developing an automated approach to studying bumblebee choices using robotic flowers.
Work is continuing on understanding how invasive ants trade off sweetness against bitterness, for use in developing psychological manipulations for ants
Work is continuing on understanding the mechanisms behind toxic bait abandonment.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Especially noteworthy progress beyond the state of the art is:
- demonstrating active abandonment of toxic baits. This has very widespread implications for control efforts, and was wholly unexpected - the project arose from field observations.
- Uncovering a systematic tolerance to bitter substances in invasive ants. If this pattern holds in various invasive ant species, it could offer a new approach to reducing off-target impacts of toxic baits. By adding bittering substances to baits, we can prevent off-target insects from consuming them, while still targetting the invasive ants. This discovery was wholly unexpected - the project arose from lab observations.
- The development of a simple and highly sensitive assay for quantifying food acceptance by ants. This tool was developed to support the original objectives of the project, but will be widely useful to both industrial and governmental labs tasked with developing and testing novel control substances.

By the end of the project, we expect the following results:
1) Develop several novel approaches to improving the efficacy of invasive and pest ant control. Currently, the most promising approaches are deploying caffeine in baits, cycling bait flavours, and adding an odour component to baits.
2) Gain a deeper understanding of how insects can be manipulated - either by us, or my other organisms (such as plants). We expect to find that manipulations such as the decoy effect can be used to change preference structures in ants and bees.
3) Demonstrate that bitterness tolerance is an unexpectedly widespread trait in invasive ants.

Invasive Argentine ants feeding on alginate hydrogel baits