Seasonal pattern in food gathering of the weaver ant Oecophylla longinoda (Hymenoptera: Formicidae) in mango orchards in Benin

Abstract

Prey capture and food scavenging activities of Oecophylla longinoda were monitored through regular weekly samplings during two consecutive years (2009–2010) in a large mango orchard of the Borgou Department of Benin, West Africa, a main mango production area located in the Sudan agro-ecological zone. In both years, interspecific competition with other ants occurred mainly during the dry season (January to March) resulting in increased captures of Formicinae, Myrmicinae and Ponerinae. More prey was caught during the rainy season (end April to end October) than during the rest of the year, with Diptera and Coleoptera prey peaking in May and June, respectively, along with the mango season. As insect prey quickly decreased during November to December weaver ants increasingly collected seeds and plant debris. A total of 241 species of insects were captured including 61 species (25.3%) associated with mango and a few with cashew, among which 48 mango pest species (78.7% of species associated with mango tree). Only five species (2.1%) of beneficial insects were captured. It is concluded that the presence of O. longinoda colonies is beneficial to perennial tree cropping systems such as mango and cashew.

Keywords:

• biological control
• Oecophylla longinoda
• Mangifera indica
• seasonality of captures
• nest contents

Acknowledgements

The authors wish to express their thanks to Wallis Zoumarou, his sons and his staff (Parakou-Korobourou) for their support and encouragements given before and during this work. We thank Dr Brian Taylor in determining Formicidae, Dr Jean-François Germain in determining Coccidae, Dr Aristide Adomou in determining Poaceae, and Modjibou Soumanou for his technical help. Thanks are also due to Dr Peter Neuenschwander for review and comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This research was supported by IITA (CGIAR) and CIRAD to whom the authors are also very grateful. This research was part of West African Fruit Fly Initiative (WAFFI) and helped to promote the weaver ant component as a key element of conservative biological control activities within the IPM-package proposed to growers.