Submitted to: Journal of Eukaryotic Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/16/2012
Publication Date: 3/1/2012
Citation: Lord, J.C., Hartzer, K.L., Kambhampati, S. 2012. A nuptially transmitted Ichthyosproean symbiont of Tenebrio molitor (Coleoptera: Tenebrionidae). Journal of Eukaryotic Microbiology. 59(3): 246-250. http://dx.doi.org/10.1111/j.1550-7408.2012.00617.x. Interpretive Summary: The yellow mealworm is a pest of stored grain products, a commercial commodity used for bird and lizard food, and a research model insect. It harbors a unique microbe that has escaped previous detection in spite of intensive study of the insect. We discovered the microbe infecting mealworm nerve chords, fat body, and testes, and we determined that it is transmitted to females during mating with infected males in which spores are bundle into spermatophores (sperm transfer packages). Gene sequencing showed that the organism is not closely related to any known species, but belongs to a group of protists whose evolutionary position is near the animal-fungi divergence. This research will help to understand the biology of an important insect and to develop means to improve its production.
Technical Abstract: The yellow mealworm, Tenebrio molitor, harbors a symbiont that has spores with a thick, laminated wall and infects the fat body and ventral nerve chord of adult and larval beetles. In adult males, there is heavy infection of the epithelial cells of the testes and between testes lobes with occasional penetration of the lobes. Spores are enveloped in the spermatophores when they are formed at the time of mating and transferred to the female’s bursa copulatrix. Infection has not been found in the ovaries. The sequence of the nuclear small subunit rDNA indicates that the symbiont is a member of the Ichthyosporea, a class of protists near the animal–fungi divergence.