Trypanosomatids associated in the alimentary canal of Bagrada hilaris (Hemiptera: Pentatomidae)

Authors: Grodowitz, Michael; Gundersen-Rindal, Dawn; ELLIOT, BRAD - Former ARS Employee; Evans, Richard; Sparks, Michael; REED, DARCY - Retired Non ARS Employee; Miles, Godfrey; Allen, Margaret - Meg; PERRING, THOMAS - University Of California

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2021
Publication Date: 1/22/2022
Citation: Grodowitz, M.J., Gundersen, D.E., Elliot, B., Evans, R.M., Sparks, M., Reed, D.A., Miles, G.P., Allen, M.L., Perring, T.M. 2022. Trypanosomatids associated in the alimentary canal of Bagrada hilaris (Hemiptera: Pentatomidae). Journal of Insect Science. 22(1):1-6. https://doi.org/10.1093/jisesa/ieab110.
DOI: https://doi.org/10.1093/jisesa/ieab110

Interpretive Summary: This manuscript describes the identification of a flagellated protozoan associated in the gut of an invasive stinkbug Bagrada hilaris. Experimentation included identification using morphology and molecular methods, culturing, and observations on potential mechanisms on transmission.

Technical Abstract: Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae), native to Africa, India, and Asia, is an invasive pest of several economically important agricultural crops in the U.S. First reported in 2008 in southern California, its range has expanded and is currently found in central California and southern Nevada, east to western and central Texas, and south to northern Mexico and more recently in Minnesota. It primarily feeds on plants in the Brassicaceae but possesses a relatively large host range, feeding and damaging corn (Zea mays L.), kale (Brassica oleracea L.), arugula (Eruca vesicaria (L.) Cav.), sunflower (Helianthus annuus L.), among others. During investigations into developing a physiological age-grading system for B. hilaris a flagellated protozoan was discovered in the alimentary canal in relatively large numbers in many individuals. This manuscript defines experimentation describing general characteristics, morphology, identification using morphology and molecular analyses, life history, culturing, and reproduction/transmission of a trypanosome observed in the alimentary canal of B. hilaris. The trypanosome appears similar to trypanosomes identified in other stinkbug species and has been tentatively identified as a species in the Blastocrithidia genus (potentially Blastocrithidia papi, a species found in the firebug - Pyrrhochoris apterus (Linnaeus, 1758) (Hemiptera: Pyrrhocoridae)). Identification was based on morphological characteristics as well as genetic analysis, though given the general belief that most trypanosomes are monoxenous additional molecular research will be needed to conclusively identify the species. Attempts at culturing were only minimally successful with increases in numbers occurring for only three days with subsequent large decreases occurring thereafter. There is a possibility that rapid decreases in pH may be partially the cause for limited success. Reproductive strategies were not fully described by experimentation but may include cyst formation, development of rosettes and fission, especially for the smaller and squatter morphological type found in older culture samples.