Submitted to: Arthropod Structure and Development
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/4/2013
Publication Date: 3/19/2013
Citation: Gerling, D., Blackburn, M.B. 2013. Immature development of Eretmocerus mundus (Hymenoptera: Aphelinidae). Arthropod Structure and Development. 42:309-314. Interpretive Summary: The tiny wasp, Eretmocerus mundus, is a parasite of whiteflies which cause extensive damage to many species of cultivated plants. These wasps could contribute to the development of novel insect control methods, if only the complex mechanisms by which they manipulate their host insect's life processes were better understood. Using histological methods and light microscopy we have studied the unique life history of these parasites and how they affect their hosts. The immature wasps induce the growth of a capsule formed by the epidermal cells of the whitefly, which appears to protect the wasp from the immune system of the host. The salivary glands of the young wasps are unusually large, suggesting that they are crucial to capsule formation and maintenance. When the parasite enters its final immature stage, the capsule disintegrates along with other host epidermal structures, leaving the parasite full contact with host tissues. The results of our study will benefit other scientists studying how these parasitic wasps control the development of their host whiteflies.
Technical Abstract: The development from egg to pupation was followed for the wasp Eretmocerus mundus parasitizing the whitefly Bemisia tabaci. This, first time study covered the histological developments and changes that the different parasitoid and host tissues have undergone during parasitism. In this work we elucidated and described structural details, heretofore only superficially mentioned in the literature. These include the presence and apparent function of very large salivary glands that probably produce materials that help regulate the host decomposition and parasitoid nutrition. Also, the gut of all instars is devoid of both peritrophic membrane and microvilli and, in the early instars has squamous rather than columnar epithelial cells. In difference from many other parasitoids, the larva usually does not come into contact with the host tissues and does not devour its entire host during development. The possible reasons for the developmental mechanisms, as well as the functions of the host capsule that envelopes the parasitoid are discussed.