Efficient Harvesting of Safe Edible Grasshoppers: Evaluation of Modified Drums and Light-Emitting Diode Bulbs for Harvesting Ruspolia differens (Orthoptera: Tettigoniidae) in Uganda

Abstract

Ruspolia differens (Serville) (Orthoptera: Tettigoniidae) is a delicacy in many African countries. It is commonly mass-harvested from the wild using light traps consisting of energy-intensive mercury bulbs which pollute the environment when poorly disposed. The catch is collected using open-ended drums which are inefficient in retaining the insects. The drums also collect nontarget insects including those that produce toxic chemicals (such as pederin) that cause severe burns to human skin. To prevent escape of trapped R. differens, trappers apply potentially hazardous substances like waste cooking oil on the walls of drums. Here, we modified the collection drum by fitting a funnel to retain R. differens; and partitioned it into three compartments with wire meshes of variable sizes to filter nontarget insects. Additionally, we replaced mercury bulbs with light-emitting diode (LED) bulbs which are energy-efficient. We evaluated the performance of the modified R. differens trap (modified drums and LED bulbs) compared to the current collection drums and mercury bulbs. The catch of R. differens in the modified drums was comparable to that of current drums. Nontarget insects were signifi-cantly filtered from the catch collected in modified drums compared to the current drums. Further, LED bulbs of 400 W trapped a comparable quantity of R. differens as 400 W mercury bulbs, but with less than half the consumption of electricity compared to the mercury bulbs. We concluded that modified R. differens light traps have better energy-use efficiency and ensure safety to collectors, processors, and consumers