Diel Patterns of Activity for Insect Pollinators of Two Oil Palm Species (Arecales : Arecaceae)

Abstract

The pollination of two oil palm species, Elaeis guineensis Jacquin and Elaeis oleifera Cortés (Arecales: Arecaceae), depends on a mutualistic relation with insects, which use male inflorescences as a brood site, and visits female inflorescences lured by the emitted odor, which is similar to that of males. Although the activity of visiting the inflorescences by these insects is critical for the adequate natural pollination of the host plant, their activity is poorly documented. In the present study, we determine the diel activity of two specialized pollinator weevils (Coleoptera: Curculionidae) on inflorescences of their respective host-palm: Elaeidobius kamerunicus Faust specialized on E. guineensis, and Grasidius hybridus O’Brien and Beserra specialized on E. oleifera. The average timing of activity was studied by using passive interception traps. Then the pattern and the duration were refined by using aspiration trapping within the active period for each insect species at the male and female inflorescences. All the experiments were conducted in an Ecuadorian oil palm plantation, located close to Amazonian forest. El. kamerunicus and G. hybridus were found to be the pollinators of E. guineensis and E. oleifera, respectively. The two species differed in their diel pattern of activity: E. kamerunicus was active in the morning and G. hybridus during a short period at dusk. For both palm species, insect visits were synchronous on both male and female inflorescences. The synchronicity is discussed as a strategy to maintain the relation mutualistic between partners. These findings increase our understanding of the oil palm pollination system.

Reproductive biology ofSyagrus coronata(Arecaceae): sex‐biased insect visitation and the unusual case of scent emission by peduncular bracts

“…belong to this tribe. In the Neotropics, several other taxa within the tribe also provide economic value to humans, namely Astrocaryum, Attalea , Bactris, Oenocarpus and Syagrus , all of which are primarily beetle‐pollinated (Listabarth 1992, 1996; Silberbauer‐Gottsberger et al 2001; Núñez‐Avellaneda et al 2005; Núñez‐Avellaneda & Rojas 2008; Auffray et al 2015; Núñez‐Avellaneda & Carreño 2017). A conspicuous, woody peduncular bract, also characteristic of cocosoid palms (Dransfield et al 2008), functions as protective cover for insects while visiting the inflorescences (Núñez‐Avellaneda et al 2005).…”

Multilocus phylogeography of the world populations of Elaeidobius kamerunicus (Coleoptera, Curculionidae), pollinator of the palm Elaeis guineensis

“…Palms (Arecaceae) and weevils of the tribe Derelomini (Coleoptera, Curculionidae) have developed a series of close host–pollinator interactions, showing a striking example of mutualistic systems (Franz and Valente, 2006). Palm inflorescences or leaves produce attractive odours for their specific pollinators (Dufay et al ., 2003; Auffray et al ., 2017) and inflorescences provide shelter and food substrate for adults and larvae. In return, weevils provide efficient pollination by flying between male and female inflorescences of their specific host.…”

Revision of the palm-pollinating weevil genus Elaeidobius Kuschel, 1952 (Curculionidae, Curculioninae, Derelomini) with descriptions of two new species

“…On and in flowers of Elaeis guineensis (Arecaceae), the oil palm. Males and females show a peak of flight activity around the inflorescences between 3 and 6 hours after sunrise (Auffray et al 2017).…”