Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2016
Publication Date: 3/25/2016
Citation: Chang, C.L., Goodman, C.L., Ringbauer Jr., J.A., Geib, S.M., Stanley, D.W. 2016. Larval x-ray irradiation influences protein expression in pupae of the Oriental fruit fly, Bactrocera Dorsalis. Archives of Insect Biochemistry and Physiology. 92(3):192-209. Interpretive Summary: The sterile insect technique (SIT) was developed and used to eradicate the new world screwworm from the southern United States and Mexico, and is now a component of many integrated pest management programs and some area-wide programs, such as the Hawaii fruit fly program. It has been particularly useful in managing tephritid fruit flies, such as the melon fly, Bactrocera cucurbitae. SIT is based on the idea of rearing and sterilizing pest insects, originally by ionizing radiation, and then releasing males into wild populations, where they compete for and mate with wild females. There are concerns with the use and international distribution of radioisotopes for SIT programs, which have led to developing X-ray irradiation protocols to sterilize insects. We considered the possibility that X-ray irradiation exerts sub-lethal impacts aside form sterilizing insects. Such effects may not be directly observable, which led us to the hypothesis that X-ray irradiation in one life stage creates reduced biological fitness and alterations in protein expression in the subsequent stage. We tested our hypothesis by X-ray irradiating larvae of the Oriental fruit fly, Bactrocera dorsalis. There are two major points. One, exposing larvae to X-ray treatments (at 30Gy) led to reduced adult emergence from the corresponding pupae and to strong reductions in fecundity, fertility and flight capacity. Two, the X-ray treatments led to substantial expression changes in 27 pupal proteins (l0 up-regulated ,17 down-regulated). We assorted the 67 spots representing these proteins into three groups, metabolism (22.4% of the spots), development (59.7%) and structure (17.9%). Our interpretation is these X-ray induced changes in biological performance parameters and protein expression indicate their adult counterparts may be disabled in their abilities to successfully compete for and mate with wild females in native habitats.
Technical Abstract: Third instar larvae were exposed to X-ray treatment of the Oriental fruit fly, Bactrocera dorsalis. Irradiated pupae were collected daily. Biological performance parameters of pupae and adults of larvae treated with X-ray irradiation were evaluated. Standard proteomics procedures such as densitometry, SDS gel electrophoresis, qPCR, bioinfomatics search were performed to identify the substantial expression protein changes.