STUDY ON INSECT DIVERSITY AND POLLINATION EFFECT ON THE YIELD OF ELEPHANT APPLE

Abstract

A study was conducted to find out the insect diversity their pollination effect and effect of netting on the yield of elephant apple during the period of June to November 2021 at the Sher-e-Bangla Agricultural University campus, Dhaka. Performance of insect pollination on the yield of elephant apple were investigated and the findings were studied. During observation in total six different species (Apis cerana, Apis dorsata, Xylocopa sp., Vespa sp., Camponotus copressus and Syrphes sp.) five different families of insects namely apidae, Vespidae, anthophoridae, formicidae and syrphidae were found under two orders (Hymenoptera and Diptera) were found as flower visiting insects of elephant apple. Among the different insect pollinators, Apis dorsata was the predominant species found to visit the elephant apple flowers during the entire flowering period. The average population of Apis dorsata was recorded 5.00 insects per flower which represented 47.62% of population of total insect pollinators visiting elephant apple flowers. The number of insect pollinator from Apidae were 2, Vespidae-1, Formicidae-1, Syrphidae-1 and Anthoporidae-1 respectively. The number of insect abundance of these following species were, Apidae-33.33%, Vespidae-16.67%, Formicidae16.67%, Syrphidae16.67%

and Anthoporidae-16.67% respectively as flower visitors. The ShannonWiener diversity index in elephant apple flower for species was 1.119, respectively

with 6 species richness, where the evenness was 0.695. For abundance of different

insect pollinators on Elephant apple flowers taken during the flowering period from

the morning 6.00 am to 7.00 pm once a week at following intervals 6.00-7.00 am,

7.00-9.00

am, 9.00-11.00 am, 11.00- 1.00 pm, 1.00-3.00 pm, 3.00-5.00 pm,the highest foraging duration was recorded for Apis dorsata 1.4 minute per flower. Considering without netting and netting condition, the average number of fruit harvested per branch of elephant apple plant were 7.00 (no.) and 0.00 (no.). Plants with netting and without netting condition, the total weight of fruit per plant of elephant apple plant were 464.00 kg and for netting treatment no fruits were developed and the total yield of elephant apple plant were 92.8 ton per ha. and for netting treatment no fruits were developed.