Metabolic rate and tethered flight performance of male Bactrocera dorsalis (Hendel) (Diptera : tephritidae) fed nutritional and semiochemical supplements

Abstract

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is an invasive species that has rapidly spread across the African continent, endangering the security of agricultural industries. Integrated pest management tactics such as the male annihilation technique (MAT) are used to suppress B. dorsalis populations in the region. The sterile insect technique (SIT) is being investigated as a viable additional tactic after its successful implementation in other parts of the world. There is evidence to suggest that pre-release nutritional and semiochemical treatments for sterilised males can enhance their competitive performance against wild type males in SIT programmes. This project investigates the impact of a diet enriched with yeast hydrolysate (YH) and/or containing semiochemicals [either methyl eugenol (ME) or eugenol (EU)] on the resting metabolic rate (RMR), flight performance, and body condition of male B. dorsalis. Respirometry revealed that a YH inclusive diet increased average RMR whereas semiochemical feeding decreased average RMR in male B. dorsalis. The analysis of male body condition in B. dorsalis showed that a protein inclusive diet positively influenced wing loading and adult body weight. Tethered flight performance results did not suggest any significant influence on flight performance parameters by dietary or semiochemical treatments. However, the average distance flown by male B. dorsalis was significantly impacted by their recorded wing area. With results indicating that males with larger wings tended to fly farther distances on average. Lipid content analysis indicated that males consuming EU had a reduced average dry weight. These findings could be useful when implementing more climate conscious SIT programs and aid in their parallel applications with MAT programs in the future.