Manipulating the behaviour of weaver ants, Oecophylla longinoda, to facilitate their integration into a programme for biological control of oriental fruit flies, Bactrocera dorsalis - SWEETS

Issues

Pest control uses large quantities of pesticides, and is therefore a key lever for reducing the use of chemical inputs in agroecosystems. Senegal, like the rest of sub-Saharan Africa, has been invaded by Bactrocera dorsalis, an invasive fruit fly classified as a quarantine pest, which causes serious damage in mango orchards. Infestations of B. dorsalis result in substantial yield losses. Ants of the genus Oecophylla are arboreal ants that are predators of this fly and are spontaneously present in orchards in tropical and subtropical Africa, Asia and Australia. However, in Africa in particular, these ants are often considered as pests by growers.

Description

It is crucial to reduce the negative effects of these ants so that their use as a biological control agent can be extended in Africa. One promising avenue is to provide them with a source of sugar in order to reduce their tending of scale insects, and also to induce other behavioural changes likely to encourage their adoption. This is achieved by installing feeders, devices produced by Biobest containing a sugar solution that rises by capillary action along a wick that the ants can reach.
This research is conducted in the context of a doctorate undertaken by a UCAD (Cheikh Anta Diop University of Dakar, Senegal) student, Philippe Correa. The first stage involves an assessment of the benefits of in situ feeders. The second consists in laboratory experiments that will help to understand the mechanisms involved in the observations made in the field. The final stage is the dissemination of research findings through scientific articles, conference presentations, and a thesis.

Expected changes

The project will result in:
- The development of a feeder, or the extended use of an existing feeder sold by Biobest.
- Better use of the biological control ecosystem service provided by weaver ants, whether in Africa, Asia or Australia, thanks to the dissemination of findings.

Expected impacts

In the long-term, this will enable:

• A reduction in pesticide use in orchards for export;
• An improvement in yields in family farming.