POPULATION DENSITY OF Elaeidobius kamerunicus Faust IN DIFFERENT SPIKELET POSITION AT ANTHESISING MALE INFLORESCENCE OF Elaeis guineensis Jacq. IN SABAH AND SARAWAK, MALAYSIA

Abstract

The oil palm male inflorescences provide food source and breeding sites for the pollinating weevil, Elaeidobius kamerunicus (E. kamerunicus). The present study examined the difference in the formation of the oil palm male inflorescences on different soil types, and how the differences affect the population density of E. kamerunicus. Samplings of adult E. kamerunicus and the spikelets of fully-anthesising oil palm male inflorescences were conducted monthly for a period of 18 months at four oil palm plantations on peat and mineral soils in East Malaysia. E. kamerunicus population density in peat soil areas was found to be lower than those in mineral soils (P<0.05). It was also found that the male inflorescences spikelet length in the study sites on peat soil areas were less uniform; spikelets on the upper part of the inflorescence were significantly shorter (= 12.80 cm

Factors Affecting Pollination and Pollinators in Oil Palm Plantations: A Review with an Emphasis on the Elaeidobius kamerunicus Weevil (Coleoptera: Curculionidae)

“…Ref. [ 92 ] suggested that longer spikelets provide more breeding sites and food sources for the weevils. Insufficient male inflorescences may contribute to a decline in the E. kamerunicus population and reduce pollination activity, leading to poor fruit set production [ 89 ].…”

“…[ 118 ] reported that the distribution of rainfall even a month prior to the data collection impacts the flight activity of E. kamerunicus on male inflorescences, especially with rain levels exceeding 500 mm. Changes in the number of rainy days can also alter the pollinating activity of E. kamerunicus since it reduces the pollen load and its viability [ 92 ]. Furthermore, pollen viability is also affected during rainy days.…”

“…Nevertheless, a few other observations documented otherwise, whereby there is a declining pattern in the E. kamerunicus population with a lack of rain [ 34 , 52 , 92 ]. The weevil population increased linearly with higher rainfall distribution, the number of rainy days, and humidity [ 12 ].…”

“…Pollen quantity and availability are also affected by the sex ratio of oil palm inflorescences, which can result in insufficient male inflorescences and negatively impact pollination efficiency [33,92]. Different oil palm varieties produce varying numbers and characteristics of male inflorescences as a source of pollen [90,91,93].…”

Assessment of Oil Palm Pollinating Weevil (Elaeidobius kamerunicus) Population Density in Biparental dura × pisifera Hybrids on Deep Peat-Soil in Perak State, Malaysia

“…Kouakou et al [ 18 ] reported that the population abundance of the pollinator weevil is strongly related to the production of the oil palm fruit-set. Male and female inflorescences both emit a distinctive aniseed scent to attract the EK pollinator for pollination [ 19 , 20 ].…”