Biodiversité des insectes pollinisateurs et leur activité de butinage sur les fleurs de Théobroma Cacao L. (Malvaceae) à Nkolbisson (Yaoundé)

Abstract

At Nkolbisson (Yaoundé, Cameroon) in 2015, during the short raining season (march-june) and short dry season (july-august), Theobroma cacao L. (Malvaceae) flowers were observed. The study of foraging behavior of insects and determining of their impact on the yields of pods realised. For this plant species, four blocks were determined from the presence banana pseudostems and for each block two different treatment were made by the presence or absence of insect protection. The activity of foraging and pollination by ants was evaluated. fruiting rate, the number of seeds per fruit and the percentage of normal seeds (well developed) were evaluated. 11 families species recorded on Theobroma cacao flowers, Formicidae, Milichidae Aphididae and occupy the 1st, 2nd and 3rd rows with 51.25%, 11.25% and 10.00% of 80 visits respectively. Formicidae attending Theobroma cacao to collect nectar and pollen.The average length of a flower tour from 1 to 5 min. Comparing the performance of the flowers left open-pollinated (in treatments with pseudostems) than free flowers (in treatments without pseudostems), it appeared that anthophilous insects have a positive impact on the fruiting of Theobroma cacaofrom 10% to 55%. Furthermore, treatment with chemical pesticides should be avoided during the flowering period of the plant studied, so as not to threaten pollinators. If the fight against pests is essential, it is recommended to use integrated pest management, including protection Apoidea and other pollinating insects.