Rearing and Larval Morphometrics of <i>Rhynchophorus phoenicis </i>(<i>Curculionidae</i>, <i>Coleoptera</i>) in Maniema Province, Democratic Republic of Congo

Bioassays were carried out to establish a suitable technique for the rearing of the palm weevil Rhynchophorus phoenicis larvae, the most abundant species of this genus in the region. Insects are common in the local diet. Locally available agricultural by-products were tested. Several morphometric parameters were recorded. Incubation of larvae on a mixture of cassava flour, coconut waste, sugar cane and plantain banana resulted in 65.1% of larvae producing cocoons and 97.8% of cocoons producing weevils. Larvae with small setae on the head capsule produce male weevils, while larvae without these setae produce females. When the feeds in the plastic boxes were packed up to 50% of the volume, the weevil survival rate at age 30 days significantly increased up to 86.7%, as compared to higher and lower box loading. Three innovative treatments based on agricultural co-products available in the region and a control (fresh stipe and oil palm kernel wood) derived from the best results of previous authors were used. On day 35, there was no significant difference between the weights and lengths of larvae fed on mixtures of coconut waste, corn meal and sugarcane and the control. Given the fact that large-scale production based on the host plant does not guarantee the conservation of the ecosystem, especially if we had to scale up to commercial production, we found an alternative feed. Our results will help improve the palm weevil rearing conditions, and the feed and they open up opportunities for the conservation of palm and raffia tree ecosystems.