Preliminary studies on alternative substrate for multiplication of African palm weevil under captive management

Abstract

The dearth of animal protein in Nigeria and the need for environmental friendly animal protein productionnecessitates the use of edible insects as an alternative protein source. To ensure the sustainability of edible insects, a cost-effective captive method of rearing needs to be devised. This study was designed to investigate alternative culture media for rearing African palm weevil Rhynchophorus phoenicis under captive management. One hundred and sixty eight palm weevils collected from ‘Mgbo swamp’ in Ebenebe town, Anambra State, were used for the study. The larvae were randomly assigned to eight different culture media (coconut fibre, coconut fibre with palm wine, sawdust of mahogany, sawdust of mahogany with palm wine, palm frond petiole, palm bunch midrib, sugarcanetops (SCT), spoilt watermelon (SWM)). Survivability, growth performance in terms of weight gain and increasein linear body measurements (within 10 weeks) as well as pupation of the larvae (within 35-40 days after the first 10 weeks) were monitored and used as indices of the suitability of each of the culture media. The result showedthat the larva thrived better in SWM and SCT but failed to pupate in SWM. The statistical analysis of the growth performance showed a significant difference (P0.05) for the linear body measurement: 4.80±0.230 cm body length increases and 1.1±0.058 cm for body width increases for larvae on SWM, while those on SCT recorded 4.183±0.0601 cm body length increasesand 1.033±0.033 cm body width increases. Cocoon formation and pupation was not observed in the larva in the SWM in the 40-day period of observation