BITING ARTHROPODS: INTEGRATED PEST MANAGEMENT
Location: Mosquito and Fly Research Unit
Title: The morphology and biology of the entomophilic Thripinema fuscum (Tylenchida: Allantonematidae), and the histopathologic effects of parasitism on the host Frankliniella fusca (Thysanoptera: Thripidae)
Submitted to: Journal of Natural History
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 26, 2012
Publication Date: May 1, 2012
Citation: Sims, K., Becnel, J.J., Funderburk, J. 2012. The morphology and biology of the entomophilic Thripinema fuscum (Tylenchida: Allantonematidae), and the histopathologic effects of parasitism on the host Frankliniella fusca (Thysanoptera: Thripidae). Journal of Natural History. 46(17-18):1111-1128.
Interpretive Summary: Natural enemies of insects are important for controlling populations that can become serious pests as well as vectoring disease causing organisms such as viruses. In this study, an Agricultural Research Service scientist in Gainesville, FL and University of Florida researchers conducted detailed histological examinations to investigate the relationships between the insect, parasite and the disease organisms that are vectored. This fundamental knowledge contributes to our basic understanding of these insects and the diseases they vector and will enable the evaluation and development of new control strategies.
Thripinema fuscum is a natural enemy capable of reducing local populations of Frankliniella fusca and reducing transmission of plant diseases vectored by F. fusca. We used light and electron microscopy to detail the in vivo life cycle of the nematode and to determine the effects of parasitism on thrips host tissues. The parasitic T. fuscum female underwent numerous morphological changes upon ingress into the host hoemocoel. She produced eggs within four to five days after ingress and the host hemocoel became packed with eggs and developing juvenile nematodes. Mature juveniles migrated to the hindgut and fully developed juveniles first emerged from the posterior end of the male or female F. fusca nine days post-parasitization. Parasitization induced a displacement of the host alimentary tract, an atrophy of the ovaries and fat body, and an alteration of energy and waste reserves in host tissues. Our observations reveal a specialized relationship showing that this parasite is well adapted to exploit host digestive, reproductive, and excretory systems. This study is a step towards understanding how histopathological alterations induced by T. fuscum influence the ability of F. fusca to transmit disease.