MSc Student (Adv. Nesrine Akkari - NHM, Andreas Wanninger)
Unit for Integrative Zoology, Department of Evolutionary Biology
University of Vienna
Abstract
Lithobiomorph centipedes represent an order of Chilopoda, with a worldwide distribution and a high diversity in temperate continental areas. Some lineages present a pronounced sexual dimorphism reflected in remarkable modifications and structures on the ultimate legs of male specimens, including thickenings, grooves, tubercles, greater glandular systems and sensory structures. Though many of these structures are documented in taxonomic studies, there is not much known about their diversity, detailed morphology and physiological functions. Consequently, our knowledge on their possible role during courtship and mating is scarce. This research aims to present a detailed documentation of these structures that we compare between different systematic groups. Additionally, hypotheses on possible functions for species ecology and reproductive biology will be presented.
For this, we investigate these structures in some selected species of the genera Lithobius Leach, 1814 and Eupolybothrus Verhoeff, 1907, showing different degrees of sexual dimorphism, using light microscopy (LM), scanning electron microscopy (SEM), µ-computed tomography (µ-CT) and histology.
Our results show that the ultimate legs of both sexes are equipped with many sensilla and glands. Different sensilla types and glandular pores are recorded and described. Many sensilla are identified as chemo- or mechanoreceptors indicating a sensory role of the ultimate legs. A special pore type was found to be associated only to male secondary sexual characters. Thickenings and dorsal sulci are present in most of the investigated species, often in both sexes but more prominent in males. Swellings, protuberances pits, grooves, tubercles and nodules often associated with pores and sensilla were only found in males. Secondary sexual characters are present on different legs and on different articles. Additional information obtained with µ-CT helped illustrating the 3-dimensional aspect of the cuticular structure of L. nodulipes Latzel, 1880 and gave a first insight of its internal anatomy. Histological sections revealed information on the sensory and glandular tissue inside the structure.
