Beyond four decades of Elaeidobius kamerunicus Faust (Coleoptera: Curculionidae) in the Malaysian oil palm industry: a review

Abstract

Oil palm (Elaeis guineensis Jacq) is an economically important crop in South-east Asia, especially in Malaysia and Indonesia. In Malaysia, oil palm is the most profitable commodity in the agriculture sector. The future of oil palm lies in obtaining a higher yield that is aligned and directed towards achieving the Sustainable Development Goals (SDG) by 2030. Elaeidobius kamerunicus was introduced into Malaysia during the late 1980s to boost the production of oil palm fruit bunches. Almost 40 years since the introduction of E. kamerunicus, significant improvements have been witnessed in the increase of oil palm yield. Nevertheless, the current concern in the oil palm sector is regarding the decreasing of fruit set that may be affected by E. kamerunicus. The weevil population plays a crucial factor in the pollination of oil palm. Several factors had been reported to reduce the weevil population such as natural enemies, interaction with local insects, pesticides, climate and male inflorescence. These factors have been addressed in this article based on various studies conducted since the first investigation in Cameroon by Syed in 1977. The role of the pollinator in terms of its biology, behaviour and pollination mechanism is also described in this article, together with the population management of the weevils. This review article will provide a summary of the current state of Elaeidobius kamerunicus in Malaysia and other neighbouring oil palm-producing countries.

Even small forest patches increase bee visits to flowers in an oil palm plantation landscape

“…Many food crops require animal pollination to maximize fruit set, size, and quality (Ollerton et al, 2011). Even oil palm is primarily pollinated by African weevils ( Elaeidobius kamerunicus Faust) that increase fruit set and yield (Caudwell, 2001; Zulkefli et al, 2021). Wild pollinators in particular contribute to the productivity and viability of many crops (Garibaldi et al, 2013) and thus to food security and nutrition (Ellis et al, 2015; Garibaldi et al, 2016).…”

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

“…The spatial organization of a landscape greatly impacts the survival and dispersal ability of most pollinator species, as resource availabilities are affected by spatial establishment and functional connectivity [ 112 , 113 ]. The spatial pattern of species, including insect pollinators, is influenced by biotic interactions such as competition, predation, and parasitism [ 10 , 12 , 40 , 114 ]. The efficiency of animal-mediated pollination services is significantly impacted by biotic interactions, such as competition between pollinators [ 80 , 115 ].…”

“…The efficiency of animal-mediated pollination services is significantly impacted by biotic interactions, such as competition between pollinators [ 80 , 115 ]. For instance, E. kamerunicus is also influenced by these biotic interactions, including predatory threats and parasitism [ 12 , 40 ].…”

“…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 ]. The population development of E. kamerunicus was reported to be faster during the rainy season, thus suggesting that it could be combined with other insect pollinators to maintain pollination activity during the rainy season [ 34 , 40 , 52 ].…”

Integrated Pest Management (IPM) in Oil Palm, Elaeis guineensis Jacq.

“…In terms of pollinating oil palms, the weevil population is crucial. Weevil populations have been found to be reduced by a number of factors, including climate, pesticides, interactions with other insects in the area, and male inflorescence [12]. The pollinator force of the weevil was sustained at a spread between 3095.2 and 19126.1 weevils per ha.…”