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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGY AND MANAGEMENT OF GRASSHOPPERS AND OTHER INSECT PESTS IN THE NORTHERN GREAT PLAINS Title: Immune Response of Mormon Crickets that Survived Infection by Beauveria Bassiana

Authors
item Srygley, Robert
item Jaronski, Stefan

Submitted to: Psyche
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 28, 2010
Publication Date: September 7, 2010
Repository URL: http://hdl.handle.net/10113/44673
Citation: Srygley, R.B., Jaronski, S. 2010. Immune Response of Mormon Crickets that Survived Infection by Beauveria Bassiana. Psyche. Vol. 2011, 5 pp., Article ID 849038, DOI:10.1155/2011/849038.

Interpretive Summary: Beauveria bassiana is a fungus that infects Mormon crickets (Anabrus simplex Haldeman) and other grasshopper pests. B. bassiana strain GHA has been developed as a biological control agent. To measure the dose-dependent response of Mormon crickets to fungal attack, we applied B. bassiana strain GHA topically to adults using doses of 51,300 to 1.75 million conidia in sunflower oil, with oil only as a control. After three weeks, we assessed the survivors’ hemolymph for fungal cells, and measured the activities of two components of the Mormon crickets’ immunity: active phenoloxidase (PO) and lysozyme. Mortality increased and the body mass of survivors decreased with conidial dose. Survivors had elevated levels of PO relative to the controls. Survivors with fungal cells visible in their hemolymph did not differ in PO activity from those with clear hemolymph. We conclude that circulating PO may be an important enzymatic defense against Beauveria infection, and that it is associated with attempted clearing of Beauveria blastospores and hyphae from Mormon cricket hemolymph.

Technical Abstract: Beauveria bassiana is an entomopathogenic Ascomycete fungus that serves as a biological control agent of Mormon crickets (Anabrus simplex Haldeman) and other grasshopper pests. To measure the dose dependent response of Mormon crickets to fungal attack, we applied B. bassiana strain GHA topically to adults using doses of 5.13x104 to 1.75x106 conidia in sunflower oil, with oil only as a control. After three weeks, we assessed the survivors’ hemolymph for fungal cells, active phenoloxidase (PO), and lysozyme. Mortality increased and body mass of survivors decreased with conidial dose. Survivors elevated PO activity to the same level independent of dose. Those with fungal cells visible in their hemolymph did not differ in PO activity from those with clear hemolymph. We conclude that circulating PO may be an important enzymatic defense against Beauveria infection, and that it is associated with attempted clearing of Beauveria blastospores and hyphae from Mormon cricket hemolymph.

Last Modified: 12/18/2014
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