Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 17, 2008
Publication Date: April 1, 2009
Citation: Shapiro, J.P., Reitz, S.R., Shirk, P.D. 2009. Nutritional manipulation of adult female Orius pumilio (Hemiptera: Anthocoridae) enhances initial predatory performance. Journal of Economic Entomology. 102:500-506. Interpretive Summary: Predatory insects are commonly shipped to growers or other end-users with a rich supply of their prey, often consisting of moth eggs that substitute for the natural prey. One important commercial biological control agent is the small predator, the insidious flower bug. After females molt into their adult stage, they must feed on a rich source of protein before developing eggs of their own. We deprived female bugs of protein for 48 hours by feeding them water or sucrose solution in capsules, both during and after shipment. By doing this prior to feeding on moth eggs, they engorged themselves when finally offered the moth eggs. This was assessed by dissecting digestive tracts and measuring them from digital photographs. Videography confirmed that they preferred to remain with the moth eggs instead of water capsules. Finally, they were offered one of their prey species, the western flower thrips. This procedure led to a 3-4-fold increase in predation on thrips. These findings indicate that growers of ornamentals or vegetables, which are prone to attack by thrips, may benefit by the increased response of unfed bugs. Insectaries may benefit through reduced costs, since less of the expensive prey will be required.
Technical Abstract: Commercial shipments of Orius insidiosus Say (Hemiptera:Anthocoridae) commonly include water and protein, the latter typically supplied by eggs from a moth such as Ephestia kuehniella Zeller. To determine whether alternative dietary conditions for young adult females might improve predation, O. insidiosus adults within 24 h of eclosion were fed on eggs of E. kuehniella plus encapsulated water, encapsulated 5% sucrose only, or encapsulated water only, for feeding periods of 24, 48, or 72 h. Digestive tract morphologies were examined by dissection and digital imaging. Females fed continuously on eggs had digestive tracts that were larger in visible area than those fed continuously on encapsulated sucrose, and areas did not change with the feeding period. When females were pre-fed encapsulated water or sucrose for 24-72 h and then fed on eggs for 3 h, the crops were highly engorged and crop areas were larger than those from females fed continuously on eggs for the same periods, although combined midgut-hindgut areas did not change. During 3-h videographic choice tests following 24, 48, or 72 h feeding on E. kuehniella eggs, females offered a choice of eggs or encapsulated water had no preference for associating with the eggs. In contrast, females pre-fed on encapsulated water or 5% sucrose solution on the same temporal feeding regimen spent a larger portion of the 3-h trial period in contact with eggs, presumably feeding. Those females pre-fed on water or sucrose, shipped overnight, and held for a total of 48 h consumed 3.6- and 4.3-fold more western flower thrips (Frankliniella occidentalis Pergande) in 3 h, respectively, than those pre-fed on E. kuehniella eggs. Survival rates of those pre-fed on sugar or water were comparable to those fed continuously on eggs. The findings suggest that egg-deprivation of females results in greater feeding activity after shipment, with no reduction in fecundity or survivability.