Location: Insect Behavior and Biocontrol ResearchTitle: Closely related Wolbachia (Rickettsiales:Rickettsiaceae) recovered from different genera of Mexican Thelytokous figitidae (Hymenoptera) Author
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2013
Publication Date: 6/1/2013
Citation: Davies, A., Sivinski, J.M., Shirk, P.D., Aluja, M. 2013. Closely related Wolbachia (Rickettsiales:Rickettsiaceae) recovered from different genera of Mexican Thelytokous figitidae (Hymenoptera). Florida Entomologist. 96(2):649-653. Interpretive Summary: Tephritid fruit flies attack hundreds of fruits and vegetables and are responsible for trade barriers wherever they occur. The mass-rearing and augmentative release of parasitoids is an effective means of control but relatively expensive. If only females could be produced then production expenses could be cut in half. The bacteria Wolbachia can change male wasps into females and bi-sexual and all female populations of some species occur in nature. However, the infection could have effects other sex-change. Scientists at the USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, in collaboration with colleagues from the Instituto de Ecologia, Xalapa, Vercruz, Mexico, compared sexual and all-female strains of a fruit fly parasitoid to see if the Wolbachia infection influenced life span and fecundity. While infected females produced more daughters when kept in individual cages this was not the case when kept in large groups. Because of their much shortened life spans Wolbachia infected females produced fewer daughters overall. As a result this particular parasitoid is not an attractive candidate for mass-rearing and biological control.
Technical Abstract: Thelytokous parasitoid strains are theoretically advantageous when utilized for biological control, as the absence of males should reduce production costs and potentially increase field efficacy. The maternally inherited intracellular bacterium, Wolbachia pipientis, is capable of inducing thelytokous reproduction, especially in hymenopteran hosts. We utilized morphologically indistinguishable Mexican arrhenotokous and thelytokous Odontosema anastrephae Borgmeier (Hymenoptera: Figitidae) fruit fly parasitoid strains to test the relative utility of each reproductive type for mass rearing. Multilocus sequence typing and antibiotic curing demonstrated that thelytokous O. anastrephae are singly infected with a novel Wolbachia strain likely responsible for parthenogenesis induction. Although uninfected arrhenotokous (W-) O. anastrephae display protandry, average female development time was not different between strains. Estimates of population doubling time were shorter for thelytokous Wolbachia-infected (W+) females when both strains were individually maintained, yet the reverse occurred when strains were reared in groups. This was primarily due to the significantly shorter lifespan of group maintained W+ females, and was in spite of grouped W- females producing more male offspring than those that were individually maintained. For logistical reasons, mass-rearing schemes require parasitoids to be reared in groups, thus, it is unlikely that W+ O. anastrephae would be advantageous relative to W- strains for augmentative release programs. Wolbachia concurrently identified from another thelytokous figitid, Aganaspis alujai Ovruski et al., from the same region are nearly identical to those from O. anastrephae, which has relevance for hypotheses concerning horizontal transmission.