Adult Survival of Delphastus catalinae (Coleoptera: Coccinellidae), a Predator of Whiteflies (Hemiptera: Aleyrodidae), on Diets of Whiteflies, Honeydew, and Honey Author(s) :Alvin M. Simmons, Jesusa C. Legaspi, and Benjamin C. Legaspi, Jr. Source: Environmental Entomology, 41(3):669-675. 2012. Published By: Entomological Society of America DOI: http://dx.doi.org/10.1603/EN11247 URL: http://www.bioone.org/doi/full/10.1603/EN11247 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. 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Entomol. 41(3): 669Ð675 (2012); DOI: http://dx.doi.org/10.1603/EN11247 ABSTRACT Delphastus catalinae (Horn) is a coccinellid predator that is commercially sold for the management of whiteßies. 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 whiteßies [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; Ϸ1% survived beyond a week at 26ЊC. Survival using the newly emerged insects was similar between those fed honeydew and honey diets, but those on the whiteßy diet had the greatest survival (Ϸ60% on day 50). However, in the experiment with mixed-aged beetles, adults on honey, and whiteßy diets performed the same over a 21-d experiment. Excluding those on the water diet, survival of beetles on the various diets ranged from Ϸ50Ð80% after 21 d. In an open choice assay across 7 h, D. catalinae adults were found on the whiteßy diet in a much greater incidence than on the other diets, and the number of beetles found on the whiteßy diet increased over time. The data supports that when D. catalinae are employed in greenhouses or Þelds for whiteßy management, during low prey populations, honeydew from the whiteßy can help sustain the popu- lation 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 whiteßies. KEY WORDS Bemisia tabaci, Delphastus catalinae, biological control, predator, diet Whiteßies are important worldwide insect pests. The Parasitoids and predators are often used in green- B-biotype sweetpotato whiteßy, Bemisia tabaci (Gen- houses to help manage whiteßies. Several species of nadius) (also reported as B. argentifolii Bellows & predators are associated with whiteßies, including Perring), and other members of the Bemisia complex Delphastus catalinae (Horn) (Coleoptera: Coccinelli- cause serious problems in crop production (Stansly dae) (Muma 1955, Hoelmer et al. 1993a, Nordlund and and Naranjo 2010). They attack an extensive number Legaspi 1996, Arno´ et al. 2010). D. catalinae is a small of plant species in greenhouse and Þeld production sized (1.4 mm long and 1.2 mm wide, male) obligate systems (Department of Agriculture and Food, Gov- whiteßy predator in the tribe Serangiini (Gordon ernment of Western Australia 2008; Simmons et al. 1994). Some aspects of its potential for the control of 2008a; Abd-Rabou and Simmons 2010) and cause dam- B. tabaci have been demonstrated (Hoelmer et al. age by feeding and by transmitting Ͼ100 plant viruses 1993b, Heinz and Parrella 1994, Liu and Stansly 1999, (Jones 2003). There is interest by the agricultural Lucas et al. 2004). community and general public for growers to produce Whiteßies in the B. tabaci complex are active in crops with as little pesticides as possible. Hence, the use of alternatives to the chemical approach, such as various climates. We reported on critical temperature the use of natural enemies, is an attractive strategy for limits for the survival of D. catalinae (Simmons and the management of whiteßies and other pests. Legaspi 2004, Legaspi et al. 2008) and its overwinter- ing capacity in mild winters of coastal South Carolina and northern Florida (Simmons and Legaspi 2007). This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or recom- Depressed populations of D. catalinae can survive mild mendation for its use by USDA. winters where the low temperatures are commonly 1 Corresponding author, e-mail: [email protected]. above 0ЊC (Simmons and Legaspi 2007). Likewise, 2 USDAÐARS, CMAVE, Center for Biological Control, Florida A&M University, 6383 Mahan Dr., Tallahassee, FL 32308. feral population of its whiteßy prey survives mild win- 3 Employed by state of Florida; contact through 2nd author. ters (Simmons and Elsey 1995). 0046-225X/12/0669Ð0675$04.00/0 ᭧ 2012 Entomological Society of America 670 ENVIRONMENTAL ENTOMOLOGY Vol. 41, no. 3 Feeding on nonprey such as nectars, pollen, sugars, locking seal plastic bag. The bag was zip sealed and and honeydew have been demonstrated to have a cotton Þber was placed around the stem of the plant positive effect on the survivorship of many natural to complete the seal of the bag so that beetles could enemies (e.g., Cottrell and Yeargan 1998, Gourdine et not crawl into the bag. For the water treatment, a al. 2003, Gourdine et al. 2005, Lundgren 2009, Sea- dental wick (Ϸ2 cm long) was saturated with deion- graves 2009). Whiteßies and aphids are well known for ized water and was placed in a 3-cm-diameter dish. their excretion of honeydew, a sticky carbohydrate, Water was used as a check, and a single water station during their feeding on plants. Studies on honeydew was provided to cages of all treatments. For the white- feeding have primarily been focused on Hymenoptera ßy diet treatment, 3Ð4 young collard leaves (Ϸ30Ð60 (e.g., Hardin et al. 2008, Dulaurent et al. 2010, Koch et cm2 per leaf) infested with all stages (but mostly eggs al. 2011). Yet, feeding on honeydew by other insects and nymphs) of B. tabaci were placed on the ßoor of is common (Schutz and Gaugler 1989, Heimpel and each cage. For the honey treatment, 10% honey by Jervis 2005, Wa¨ckers 2005, Lundgren 2009). Moreover, volume in deionized water was used to saturate a some coccinellids have been observed to feed on hon- cotton dental wick (Ϸ2 cm long) in a 3-cm-diameter eydew produced by their prey (Hagen 1962). The dish. Three stations of honey-solution-cotton wicks amount and quality of honeydew produced by B. were provided for the honey treatment cage. For the tabaci can vary based on instar and temperature (Hen- honeydew treatment, an 8.3-cm-diameter petri dish neberry et al. 2001). When biological organisms are top was placed on a greenhouse bench below a B. successfully used to manage populations of whiteßies, tabaci-infested ÔEarly ProliÞcÕ squash (Cucurbita pepo the whiteßy population can resurge from new infes- L.) plant (ßowering stage) for 2Ð3 d to catch honey- tations, from low populations, or both, which escaped dew. Subsequently, two of the petri dishes with hon- attack. After the prey population is decimated, the eydew were provided for the honeydew treatment natural enemy may also die because of little or no food. cage. The tops of all cages were covered with Þne When whiteßies are no longer present, it is not known mesh screen and secured with a pair of rubber bands if remaining honeydew may help sustain the natural around each cage after 20 adult D. catalinae were enemy or not. Moreover, when the whiteßy popula- released in each cage within 24 h after emergence. To tion is scarce or depleted, an alternative food may help obtain a known age of adult beetles, pupae were col- sustain the natural enemy and extend its effectiveness. lected from the colony and held in cages in the lab- Although small size coccinellids are often over- oratory at 26ЊC, and were monitored for emergence. looked, they are important in regulating many ho- A cage for each treatment was then held in an envi- mopterous pests (Hagen 1962). Knowledge of the ronmental chamber (model I-36VL, Percival, Perry, ecology of whiteßy predators will facilitate their role IA) for 50 d at 26ЊC and 80Ð85% RH. Lighting in the as a pest management component. The purpose of this chamber was by ßuorescent bulbs oriented vertically study was to determine any inßuence of selected non- along two opposite walls; the photoperiod regime was whiteßy diets on survival of adult D. catalinae as com- 16:8 (L:D) h. Daily observations were made on sur- pared with its standard whiteßy prey.