Beyond the limits of light; an application of Super-Resolution Confocal Microscopy (cCLSM) to investigate Eocene amber microfossils

Authors: VORONTSOV, DMITY - Russian Academy Of Sciences; KOLESNIKOV, VASILIV - Tyumen State University; VORONEZHSHAYA, ELENA - Russian Academy Of Sciences; PERKOVSKY, EVGENY - National Academy Of Sciences Of Ukraine; BERTO, MARIELLE - University Of Florida; MOWERY, JOSEPH - US Department Of Agriculture (USDA); Ochoa, Ronald - Ron; KILMOV, PAVEL - Purdue University

Submitted to: Diversity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2023
Publication Date: 3/23/2022
Citation: Vorontsov, D.D., Kolesnikov, V., Voronezhshaya, E.E., Perkovsky, E., Berto, M., Mowery, J., Ochoa, R., Kilmov, P. 2022. Beyond the limits of light; an application of Super-Resolution Confocal Microscopy (cCLSM) to investigate Eocene amber microfossils. Diversity. 13(4):865. https://doi.org/10.3390/life13040865.
DOI: https://doi.org/10.3390/life13040865

Interpretive Summary: Amber fossils, because they are preserved with great fidelity and are relatively common, provide a snap shot in time of the history of evolution on Earth. The oldest amber-preserved arthropod specimens are from around 230 million years ago. This amber material captured a mite associated with insects, the understanding of this association and the comparison with similar mites today may have an impact in the control of beetles associated with fruit trees. The mite in this case is similar to a mite species associated with beetles affecting avocado groves. This information will be useful for scientists, integrated pest management, and field research biocontrol researchers.

Technical Abstract: Amber is known as one of the best sources of fossil organisms preserved with exceptional fidelity. Historically, different methods of imaging have been applied to amber, including optical microscopy and micro-tomography. These methods are sufficient to resolve millimeter-scaled fossils. However, microfossils, such as microarthropods, require a better resolution. Here we describe a non-destructive method of super resolution confocal microscopy (sCLSM) to study amber-preserved microfossils, using a novel astigmatid mite species (genus Histiogaster) from Eocene Rovno amber as a model. We show that the resolution obtained with sCLSM is comparable to that of scanning electron microscopy (SEM) routinely used to study modern mites. We compare sCLSM imaging to other methods that are used to study amber inclusions and emphasize its advantages in examination of unique fossil specimens. Furthermore, we show that the deterioration of amber, which manifests in itself darkening, positively correlates with its increased fluorescence. Our results demonstrate a great potential of the sCLSM method for imaging of the tiniest organisms preserved in amber.