Entomophil pollination of oil palm in West Africa - preliminary research. (Paper presented at the Poster Session).

The arrival frequency of the insects on the flowers reflects an important activity on the female inflorescences. This activity has been studied and compared on male and female inflorescences, at half-hourly intervals and during several periods in the year. This has shown that a preponderant species at one time can be replaced by another species during the year as function of the climatic conditions. The insects are very seldom found on the hybrids Elaeis guineensis x E. melanococca studied, but were notably present on E. melanococca. The percentage of fertile fruits on the hybrid studied was quite low while on Elaeis melanococca, it was at least 25%. This difference in fertile fruit (although the pollen production on hybrids and E. melanococca is low) reflects the presence or absence of the insects. When a female inflorescence was enclosed in a cage (with mosquito net with large sticks) and treated each day with a concentrated solution of Propoxcur to avoid the arrival of all insects on the flower, a low percentage of fertile fruit was obtained i.e. 29.8% to 34.9% in comparison with the control of 55.7% to 66.8%. This shows that the insects must play a role that is not negligible in the pollination. Thus pollen dispersion is not only by the wind. This confirms the fact that insects play a relatively important role in pollination of oil palm. This role is dependent not only on one preponderant species but on several species whose populations change during the year. At the same time, some of the insects are harmful for the bunches. Therefore, more complete studies have to be undertaken on the different species found on the inflorescences in West Africa in order to know perfectly their efficacy as pollinators before they are used deliberately in other countries.