Arthropod Biology Impacts of Extended Laboratory Rearing on Female Fitness in Florida Colonies of the Parasitoid Spalangia cameroni (Hymenoptera: Pteromalidae) With an Analysis of Wolbachia Strains E.T. Machtinger, 1,2 C. J. Geden, 3 E. D. LoVullo, 3 and P. D. Shirk 3 1 Department of Entomology and Nematology, University of Florida, PO Box 110620, Gainesville, FL 32611 (irishtangerine@ufl.edu), 2 Corresponding author, e-mail: irishtangerine@ufl.edu, and 3 USDA-ARS, Center for Medical, Agricultural, and Veterinary Entomology, 1600 S. W. 23rd Dr., Gainesville, FL 32608 (chris.geden@ars.usda.gov; Eric.LoVullo@ARS.USDA.GOV; paul.shirk@ars.usda.gov) Received 3 July 2015; Accepted 6 November 2015 Abstract Spalangia cameroni Perkins is used as a biological control agent of filth flies. These parasitoids are reared com- mercially, but little is known about the impact of colony age on host-seeking and life history parameters. Host- seeking in bedding from equine stalls (pine shavings and manure) was analyzed with two colonies, one estab- lished in 2000 and one in 2010 (144 and 24 generations in colony). These two colonies, and a colony established in 2012 colony (4 generations), were analyzed for differences in female longevity and fecundity. Wolbachia were analyzed in each colony to document sequence variants. All wasps collected to start parasitoid colonies were from the same dairy in Gilchrist County, FL, but collected on different dates. Parasitoids from the 2000 col- ony parasitized fewer hosts than ones from the 2010 colony when challenged in a complex environment. Life history parameters were different between individuals in the colonies. Differences in reproductive productivity between the colonies could not be correlated to the presence or sequence variant of Wolbachia. New Wolbachia wsp and ftsZ sequences were identified in these colonies. Multiple strains of Wolbachia were found in each colony, and their presence did not vary among colonies. The invariance in strain presence suggests that Wolbachia strains were not lost during colony maintenance, i.e., lost through selection or random genetic drift. Key words: biological control, Musca domestica, Stomoxys calcitrans, filth fly, parasitoid Commercially produced pupal parasitoids (Hymenoptera: Pteromalidae) are used as biological control agents of filth flies on livestock facilities. The use of pupal parasitoids as part of a control program for house flies (Musca domestica L.) and stable flies (Stomoxys calcitrans (L.)) (Diptera: Muscidae) has become more common as fly resistance to insecticides has increased (Chapman et al. 1993, Marc ¸on et al. 2003, Kaufman et al. 2010, Pitzer et al. 2010, Scott et al. 2013). Spalangia cameroni Perkins is one of the most common commercially available pupal parasitoids. It is not well understood to what exent long-term mass rearing might alter its fitness and host-seeking ability, subsequently affecting fly control. Fecundity, female longevity, and mobility can be quickly altered by rearing in laboratory colonies (Roush 1990, Latter and Mulley 1995) as a result of inbreeding depression, selection, and genetic drift. These alterations can produce individuals that are notably dif- ferent from their wild counterparts (Boller 1972, Vargas and Carey 1989). Filth flies develop in habitats that include decomposing ani- mal waste and organic matter. The loss of genetic variation in small source populations of laboratory colonies may reduce their ability to adapt in changing environments (Bijlsma and Loeschcke 2005), as would be necessary in these highly ephemeral habitats. Compromised fitness associated with long-term mass-rearing may reduce host-seeking ability, compromising subsequent parasitism (Chambers 1977, Dietrick 1981, Hagan 1986, Latter and Mulley 1995). Inbreeding depression in haplodiploid parasitoids has been con- sidered to be minimal because detrimental recessive genes are expressed in males and subsequently deleted (Bruckner 1978, Crozier 1985, Werren 1993, Antolin 1999, Vayssade et al. 2014). However, substantial inbreeding depression has been observed in several species of parasitoids after as few as four generations (Legner 1979, Henter 2003), suggesting that parasitoids are subject to behavioral and physical phenotypic shifts due to genetic drift dur- ing colony rearing. Unlike some other parasitoids, S. cameroni shows no reluctance to mate with siblings and is thus at greater risk for inbreeding depression under intensive laboratory rearing (King and King 1994). V C The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com 1 Annals of the Entomological Society of America, 2015, 1–7 doi: 10.1093/aesa/sav118 Research article Annals of the Entomological Society of America Advance Access published November 27, 2015