Location: Fruit and Tree Nut ResearchTitle: An insect pupal cell with antimicrobial properties Author
|Shapiro Ilan, David|
Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2014
Publication Date: 1/1/2015
Citation: Shapiro Ilan, D.I., Mizell, R.F. 2015. An insect pupal cell with antimicrobial properties. Journal of Invertebrate Pathology. 124:114-116. Interpretive Summary: Just like humans and other animals, insects can get sick. In fact, in the soil there are many disease-causing agents that can attack insects and kill them. Therefore, insects have developed various ways to defend themselves such as manually removing disease-causing spores or initiating an internal immune response. In this study, we investigated a new way that insects might protect themselves against infection. We focused on the pecan weevil, which is a key pest of pecans that spends most of its two or three year life cycle in the soil. When the weevil is in the soil it forms a pupal cell. We hypothesized that the pupal cell would have antimicrobial properties, which would help the insect defend against harmful pathogens. Our hypothesis was correct; soil from the pupal cell was suppressive to a fungal pathogen that commonly infects pecan weevil. We think that this is the first time anyone found that a pupal cell possesses antimicrobial properties. The research is important because it helps us understand how insects defend themselves against diseases. The findings could help us find ways to better combat pests, or help us find ways to keep beneficial insects (such as bees) healthy. Additional research is needed to determine exactly how the pupal cell suppresses disease causing agents.
Technical Abstract: Soil-dwelling insects have developed various defense mechanisms to defend against pathogen infection. The pecan weevil, Curculio caryae, spends two to three years in the soil inside an earthen cell. We hypothesized that the cell may possess antimicrobial properties. In a laboratory study, we tested the hypothesis using the fungus Beauveria bassiana as a model. B. bassiana is a common endemic pathogen of C. caryae. We compared the number of colony-forming-units on selective media when B. bassiana was exposed to autoclaved soil, non-autoclaved soil, or soil from a C. caryae pupal cell. Relative to other treatments and controls, results indicated that soil from C. caryae cells was suppressive to B. bassiana. To our knowledge this is the first report of antimicrobial properties being associated with and insect soil cell. The findings expand our knowledge of host-pathogen relationships. Additional research is needed to determine the basis for the suppressive effects observed.