Communities of oil palm flower-visiting insects: investigating the covariation of Elaeidobius kamerunicus and other dominant species.

Akhmad Rizali,Fatma Ramadhani Wahyuningtyas,Bambang Tri Rahardjo,Nurindah Nurindah,Yann Clough,Sri Karindah,Bandung Sahari

doi:10.7717/peerj.7464

Abstract

Insects visit flowers not only to forage for nectar or pollen but also to search for hosts or prey, and to look for suitable habitats for breeding sites. In oil palm flowers, it has been documented that not all flower-visiting insects are pollinators, but some insects are recognized as predators, parasitoids or saprophages, which may affect the abundance and persistence of the weevil pollinating oil palm, Elaeidobius kamerunicus. We studied the community of oil palm flower-visiting insects and investigated the covariation between the abundance E. kamerunicus and that of other dominant species. Ecological research was conducted in oil palm plantations with different tree ages in Central Borneo. Our results found that tree age and flower type of oil palm did not influence the abundance and species richness of flower-visiting insects, but significantly affected their species composition. There was a significant positive relationship between the abundance of E. kamerunicus and the fly Scaptodrosophila sp, indicating that these species covariate in oil palm flowers. These findings suggest that understanding the covariation between E. kamerunicus and Scaptodrosophila sp may help develop the conservation strategies for E. kamerunicus to support the sustainable production of oil palm.

Highlights

The presence of insects in oil palm flowers is related to their activity to look for nectar or pollen (Lajis, Hussein & Toia, 1985; Syed, 1979) or to search for prey (Hakim et al, 2017) as well as for suitable habitat for breeding sites (Corley & Tinker, 2003; Moore, 2001)
We studied the community of oil palm flower-visiting insects in oil palm plantation in Central Borneo, Indonesia
Other dominant insects were Diptera, dominated by Scaptodrosophila sp, Hymenoptera which were dominated by ants (Pheidole sp) and Lepidoptera which were dominated by a moth species (Gelechiidae sp) (Table 2, Figs. 2B–2D)

Summary

Introduction

The presence of insects in oil palm flowers is related to their activity to look for nectar or pollen (Lajis, Hussein & Toia, 1985; Syed, 1979) or to search for prey (Hakim et al, 2017) as well as for suitable habitat for breeding sites (Corley & Tinker, 2003; Moore, 2001). The identity of the insects visiting oil palm flowers depends on the geographical region. In Africa, which is the origin area of oil palm plants, the most dominant flower visitors are Elaeidobius kamerunicus, E. plagiatus and E. subvittatus (Coleoptera: Curculionidae): these insects have an important role as a pollinators (Syed, 1979). Communities of oil palm flower-visiting insects: investigating the covariation of Elaeidobius kamerunicus and other dominant species. In Indonesia, since the introduction of E. kamerunicus in 1983, this weevil has become the most abundant oil palm flower-visiting insect, and its presence has been an important contribution to increasing fruit set of oil palm (Susanto, Purba & Prasetyo, 2007)

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Discussion

Conclusion