Submitted to: Psyche
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2013
Publication Date: 1/4/2014
Citation: Shelby, K., Habibi, J., Puttler, B. 2014. An ultrastructural and fluorescent study of the teratocytes of Microctonus aethiopoides Loan (Hymenoptera: Braconidae) from the hemocoel of host alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae). Psyche. Available: http://dx.doi.org/10.1155/2014/652518. Interpretive Summary: An internal parasitic wasp is one of the best biological agents for controlling weevils that are serious pests of alfalfa. Large, specialized cells, called teratocytes, have always been found associated with those immature wasps that successfully develop within the weevil host. However, very little is known about the structure and function of these teratocytes. For this study, electron microscopic analysis of the internal structure of teratocytes revealed an extensive network of structures that are known to serve the purpose of import, digest, store and export of substances that are the building blocks of living organisms. This discovery of the internal structure within teratocytes strongly suggests that these are highly specialized cells that serve an important metabolic purpose for wasp development. That knowledge can be very useful in assisting scientists attempts to effectively use these parasites to control the weevil.
Technical Abstract: The braconid endoparasitoid Microctonus aethipoides is a koinobiont endoparasitoid of alfalfa weevil adults. After oviposition and subsequent egg maturation, large trophic cells called teratocytes dissociate and are released into the host hemocoel. Teratocytes are present in large numbers and are visible to the naked eye. It is thought that they accumulate host hemocoelic metabolites for later consumption by the parasitoid larvae. We have undertaken a microscopic study of these gargantuan and complex cells. Parasitized adults were dissected into medium, and hemolymph cells were fixed, embedded and cut into 1 um sections. Teratocytes were stained with various specific fluorescent dyes for plasma membrane, Golgi, nuclei, lysosomes, mitochondria and endoplasmic reticulum. Analysis of fluorescent images showed that these cells do not have condensed nuclei ER was abundant around the nuclear envelope. Lysosomes were positioned around the periphery of the nucleus and the Golgi apparatus was significantly enlarged, being located around the nuclear envelope.