The Life Cycle of the Root Borer,Oryctes agamemnon, Under Laboratory Conditions

Abstract

The root borer, Oryctes agamemnon Burmeister (Coleoptera: Scarabaeidae), has become a serious pest of date palm trees in southwest Tunisia. Under natural conditions, mated females lay eggs in different parts of palm tree: between the hairy roots, all along the stem at the leaf axils and at the base of cut branches. Larvae bore into targeted places of the plant and were never seen outside. Pupation takes place in the plant and emergence of the adults begins in June. Larval feeding causes extensive damage to the respiratory roots. To examine the life cycle more closely, the O. agamemnon life cycle was studied under laboratory conditions. Different larval stages were collected from infested oases in Tozeur and placed in plastic boxes with natural food that was collected from the oases. After emergence, adults were paired in opaque plastic boxes for mating with the same food substrate which also served as an oviposition site. Eggs were collected daily and isolated in new boxes. Hatched eggs were recorded. The number of larval instars was determined by measuring the width of cephalic capsules. Under laboratory conditions (23 ± 2'C and 55 ± 6% RH)embryogenesis took 14.3 ± 1.42 days and the first, second and third larval instars were 33.1 ± 2.69, 63.88 ± 6.6 and 118.3 ± 13.38 days respectively. The pupal period lasted 24.1 ± 3.02 days and the adult 65.27 ± 9.48 days. These facts indicated that O. agamemnon is univoltine.

Use of Light Traps and Differing Light Color to Investigate Seasonal Abundance of the Date Palm Pest, <I>Oryctes agamemnon arabicus</I> (Coleoptera: Scarabaeidae)

“…These results offer good evidence that O. agamemnon arabicus in the UAE undergo only one generation per year. These Þndings are in agreement with the results of the life span study conducted by Soltani et al (2008) in which O. agamemnon arabicus was reported to be a univoltine insect requiring Ϸ 6 mo of feeding during its larval stages. Our Þeld and laboratory observations (M.A.A., unpublished data) are supportive of the long duration needed for larval development.…”

“…Agamemnon arabicus larvae bore into the trunk and feed on the roots of date palm trees can cause considerable damage (Gassouma 1991, Soltani et al 2008. Damaged areas (wounds) on the tree trunk can attract females of the red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), the most detrimental date palm insect pest in UAE, which lay eggs in the wounds.…”

Description of the third larval instar and pupa of Geniates barbatus Kirby (Coleoptera, Scarabaeidae, Rutelinae)

“…It is not known if the larva killed the individual being consumed, but active sporadic cannibalism behavior has been reported for some scarab larvae (e.g. Soltani et al 2008). On the other hand, some scarab larvae seem to attack and kill other larvae without feeding on them (e.g.…”

Some biological aspects of Leucothyreus femoratus (Burmeister) (Coleoptera, Scarabaeidae), in oil palm plantations from Colombia

“…One possible reason might be cannibalism observed during the study, especially in third instar larvae that consume smaller individuals and pupae. Similar antagonistic behavior involving severe attacks on the abdomen and locomotor appendages was observed in Oryctes agamemnon (Burmeister) (Soltani et al, 2008). It is unknown whether this insect shows similar behavior under natural conditions.…”