Recognition of genital coevolution in mites using multi-microscopy technologies

Authors: COMBITA-HEREDIA, ORLANDO - THE OHIO STATE UNIVERSITY; GULBRONSON, C. - U.S. DEPARTMENT OF AGRICULTURE (USDA); Ochoa, Ronald - Ron; QUINTERO-GUTIERREZ, E.J. - NON ARS EMPLOYEE; Bauchan, Gary; KLOMPEN, HANS - THE OHIO STATE UNIVERSITY

Submitted to: Proceedings of the National Academy of Sciences (PNAS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2020
Publication Date: 8/18/2021
Citation: Combita-Heredia, O., Gulbronson, C., Ochoa, R., Quintero-Gutierrez, E., Bauchan, G.R., Klompen, H. 2021. Recognition of genital coevolution in mites using multi-microscopy technologies. Proceedings of the National Academy of Sciences(PNAS). 16(8):001-019. https://doi.org/10.1371/journal.pone.0254974.
DOI: https://doi.org/10.1371/journal.pone.0254974

Interpretive Summary: Little is known about the intricate reproductive systems of mites associated with dung beetles. The genitalia of the mites are found on the pincer-like mouth parts of the mite. The male mite exhibits a colossal, coiled spring-like structure which unfurls inside the equally complex coiled structure inside the female’s mite lower pincher. Multiple microscopy techniques were used in this study including video stereomicroscopy, fluorescence microscopy, low-temperature scanning electron microscopy (LT-SEM) and confocal laser scanning microscopy (CLSM). All technologies were used to study the external surfaces, however, the CLSM was uniquely successful at imaging internal structures critical for observing female anatomy. These microscopy technologies, along with computerized imaging enhancement techniques, proved that the male reproductive system largely matches the internal spiral structure of the female mites. These studies are valuable for the study of sexual selection among mite species and will be used by mite specialist, entomologists, behavioral scientists, and ecologists

Technical Abstract: Genitalic structures in males and females of Megalolaelaps colossus, mites associated with the dung beetle, Oxysternon conspicillatum, were examined using multiple microscopy techniques including video stereomicroscopy, fluorescence microscopy, low-temperature scanning electron microscopy (LTSEM) and confocal laser scanning microscopy (CLSM). Both LTSEM and CLSM are well suited for obtaining surface images. However, CLSM proved to be a valuable technique for observing internal anatomical structures. The long and coiled spermatodactyl on the chelicera of the males largely matches an internal spiral structure in the females in shape, size and direction, in accordance with expectations under a sexual conflict model. These microscopy technologies, along with computerized imaging enhancement techniques, prove to be important for the study of genitalia of Megalolaelaps colossus enabling the development of hypotheses for the mechanics of mating in these mites.