Sensory Physiology of mating-related signals

Sensitivity and mating flight times are bound

Vienna/Würzburg – mechentel news – There is evidence of a correlation between general photosensivitiy and sensitivity of speciesspecific mating flight times, so the result of an investigation by Mag Streinzer M. et al. biocentre of the University of Würzburg and Faculty of Life Sciences, University of Vienna. Ranging from dwarfs to giants, the species of honeybees show remarkable differences in body size that have placed evolutionary constrains on the size of sensory organs and the brain. Colonies comprise three adult phenotypes, drones and two female castes, the reproductive queen and sterile workers. The phenotypes differ with respect to tasks and thus selection pressures which additionally constrain the shape of sensory systems. In a first step to explore the variability and interaction between species size-limitations and sex and caste-specific selection pressures in sensory and neural structures in honeybees, we compared eye size, ommatidia number and distribution of facet lens diameters in drones, queens and workers of five species (Apis andreniformis, A. florea, A. dorsata, A. mellifera, A. cerana). In these species, male and female eyes show a consistent sex-specific organization with respect to eye size and regional specialization of facet diameters. Drones possess distinctly enlarged eyes with large dorsal facets. Aside from these general patterns, we found signs of unique adaptations in eyes of A. florea und A. dorsata. In both species, drone eyes are disproportionately enlarged. In the increased eye size results from enlarged facets, a likely adaptation to crepuscular mating flights. In contrast, the relative enlargement of drone eyes results from an increase in ommatidia number, suggesting strong selection for high spatial resolution. Comparison of eye morphology and published mating flight times indicates a correlation between overall light sensitivity and species-specific mating flight times, so the scientists in the February issue 2013 of the journal PLoS one. The correlation suggests an important role of ambient light intensi ties in the regulation of species-specific mating flight times and the evolution of the visual system. Our study further deepens insights into visual adaptations within the genus and opens up future perspectives for research to better understand the timing mechanisms and sensory physiology of mating related signals.

 Authors: Streinzer M, Brockmann A, Nagaraja N, Spaethe J. Correspondence: Department of Behavioral

Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, Germany ; Department
of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria. Study: Sex and
caste-specific variation in compound eye morphology of five honeybee species. Source: PLoS One.
2013;8(2):e57702. doi: 10.1371/journal.pone.0057702. Epub 2013 Feb. Web: http://www.plosone.org/
article/info:doi/10.1371/journal.pone.0057702