Simmons Alvin M, Legaspi Jesusa C, Legaspi Benjamin C
U S Vegetable Laboratory, USDA-ARS, Charleston, SC 29414, USA.
Environ Entomol. 2012 Jun;41(3):669-75. doi: 10.1603/EN11247.
Delphastus catalinae (Horn) is a coccinellid predator that is commercially sold for the management of whiteflies. A study was conducted to assay the effect of selected diets on the survival of adult D. catalinae. Treatments of water (as a control), 10% honey, honeydew, and whiteflies [Bemisia tabaci (Gennadius)] were provided to the beetles in laboratory assays. Newly emerged, unfed adult insects were used at the start of a survival experiment with trials lasting 50 d. Another survival experiment used mixed-aged adults from a greenhouse colony, and the trials lasted 21 d. Survival was poor on a diet of solely water; 1% survived beyond a week at 26°C. Survival using the newly emerged insects was similar between those fed honeydew and honey diets, but those on the whitefly diet had the greatest survival (60% on day 50). However, in the experiment with mixed-aged beetles, adults on honey, and whitefly diets performed the same over a 21-d experiment. Excluding those on the water diet, survival of beetles on the various diets ranged from ~50-80% after 21 d. In an open choice assay across 7 h, D. catalinae adults were found on the whitefly diet in a much greater incidence than on the other diets, and the number of beetles found on the whitefly diet increased over time. The data supports that when D. catalinae are employed in greenhouses or fields for whitefly management, during low prey populations, honeydew from the whitefly can help sustain the population of this predator. Moreover, a supplemental food such as a honey solution can help sustain the population of D. catalinae when the prey is decreased to low numbers. These results may help in the development of strategies to enhance the utility of predators for the management of whiteflies.
小黑瓢虫（Delphastus catalinae (Horn)）是一种瓢虫科捕食性昆虫，已商业化销售用于防治粉虱。开展了一项研究，以测定特定食物对成年小黑瓢虫存活的影响。在实验室试验中，为甲虫提供水（作为对照）、10%蜂蜜、蜜露和粉虱[烟粉虱（Bemisia tabaci (Gennadius)）]等处理。在一项持续50天的存活实验开始时，使用刚羽化、未进食的成年昆虫。另一项存活实验使用来自温室种群的不同年龄段成年个体，试验持续21天。仅以水为食物时存活率很低；在26℃下，约1%的个体能存活超过一周。使用刚羽化的昆虫时，取食蜜露和蜂蜜食物的个体存活率相似，但取食粉虱食物的个体存活率最高（第50天时约为60%）。然而，在不同年龄段甲虫的实验中，取食蜂蜜和粉虱食物的成年个体在21天的实验中表现相同。排除以水为食物的个体，21天后，取食各种食物的甲虫存活率在约50 - 80%之间。在一项持续7小时的开放式选择试验中，发现小黑瓢虫成年个体取食粉虱食物的发生率远高于其他食物，且在粉虱食物上发现的甲虫数量随时间增加。数据表明，当在温室或田间利用小黑瓢虫防治粉虱时，在猎物数量较少期间，粉虱分泌的蜜露有助于维持这种捕食者的种群数量。此外，当猎物数量减少到很低时，如蜂蜜溶液等补充食物有助于维持小黑瓢虫的种群数量。这些结果可能有助于制定提高捕食性昆虫防治粉虱效用的策略。
