Monitoring Insect Populations in Cocoa Agro-Ecosystems within the Catchment of the Bobiri Forest Reserve in Ghana

P. P. Bosu; K. Frimpong-Anin; M. K. Adjaloo; H. Braimah; W. Oduro; C. E. Annoh; K. Aidoo; P. K. Kwapong

P. P. Bosu Forestry Research Institute of Ghana, Council for Scientific Industrial Research, University P.O. Box 63, Kumasi, Ghana
K. Frimpong-Anin Crops Research Institute, Council for Scientific Industrial Research, P.O. BOX 3785, Fumesua-Kumasi, Ghana
M. K. Adjaloo Technology Consultancy Centre, College of Engineering, KNUST, Kumasi
H. Braimah Crops Research Institute, Council for Scientific Industrial Research, P.O. BOX 3785, Fumesua-Kumasi, Ghana
W. Oduro Faculty of Renewable Natural Resources, Department of Range and Wildlife, KNUST, Kumasi
C. E. Annoh Department of Pharmaceutical Science, School of Applied Sciences, Central University P. O. Box 2305, Tema, Ghana.
K. Aidoo Honey Center, P. O. Box 169, Saltpond, Ghana
P. K. Kwapong Department of Entomology and Wildlife, School of Biological Sciences, University of Cape Coast, Cape Coast, Ghana

Abstract

Population diversity of insects in an ecosystem at any given time is a good indication of their role in ecosystem function, and it helps to facilitate their management. A two-year monitoring survey was conducted in cocoa farms within the catchment of the Bobiri Forest Reserve in Ghana. Pan traps consisting of fluorescent white, blue and yellow plastic bowls were set in 10 cocoa farms spread out in the study area. On each farm, 30 traps consisting of 10 white, 10 yellow and 10 blue were each mounted on a 1m high 5 cm wide PVC pipe stand. Sampling was carried out during the major and minor cocoa flowering seasons in 2011 and 2012, with each sampling session lasting approximately 48 hours. A total of 496 insects were collected at the end of the survey period with yellow and white traps being more attractive to pollinators in the study area. The dominant taxa recorded were Dipterans 177 (35.69%), of which midges constituted 79 (15.9%). There were 175 (35.3%) Hymenopterans, which included 100 (20.2%) ants, 57 (11.5%) stingless bees, 15 (3.0%) wasps, and 3(0.6%) honey bees. There were 77 (15.5%) coleopterans (beetles) and lepidopteran groups recorded and 52 (10.5%) lepidopterans. The primary cocoa pollinator Forcipomyia midge was recorded both in the minor (October-January) and major (April-July) cocoa flowering seasons. Midgesâ€™ population in the cocoa ecosystem proved to be generally high in the wet season. The results suggest differences in the adaptation of resident insects in the cocoa agroecosystem.