Enhanced oviposition in the insidious flower bug, orius insidiosus (Hemiptera: Anthocoridae) with a partially purified nutritional factor from prey eggs

The insidious flower bug, Orius insidiosus (Say), can be maintained on a minimal artificial diet composed of brewers yeast, soy protein hydrolysate and chicken yolk. However, egg production is poor even though the level of protein in the diet exceeds the amount consumed by adults that are fed insect eggs and have higher levels of egg production. We therefore fractionated eggs of the almond moth, Ephestia kuehniella Zeller by preparative isoelectric focusing and bioassayed the resultant fractions in test diets. Ovipositional rates were evaluated using a short 1-week bioassay. Adult predators were placed on the diets the third day after eclosion, allowed to feed for six days, and then provided with an oviposition substrate for 24 h on day seven. Egg production significantly increased only in a fraction with an isoelectric point of pH 5. SDS-PAGE revealed the presence of several Commassie blue-stained bands; however, the nature of the factor is unknown. These results point to a fecundity factor required by females of O. insidiosus for egg laying that potentially may be used to supplement artificial diets for Orius species by commercial producers of beneficial insects.