Comparison of selected parts of larval morphology in some species of the genus Chironomus (Diptera: Chironomidae) using Scanning Electron Microscope

Abstract

Comparison of small sized and weakly chitinized structures such as the labrum (labral setae SI-SIII, labral lamella, tormal bar, pecten epipharings) and the maxilla (maxillary palp, lacinial chaeta) is provided in larvae of Chironomus plumosus, C. balatonicus, C. usenicus C. melanotus, C. acerbiphilus, and C. riparius using Scanning Electron Microscope (SEM). The general morphological structures of the labrum and the maxilla were similar in all of the Chironomus larvae. They differed only in fine details such as labral seta, mainly S I. Seta S I is always plumose on each side and differently figured: elongated in C. balatonicus, C. plumosus, C. melanotus and C. usenicus; rounded in C. acerbiphilus and C. riparius. Some differences were also observed in the shape, length or ratio of lacinial chaetae (LCh I, LCh II). Based on morphological variation in the larvae of some Chironomus species, results indicated that the SEM method is apparently beneficial and useful in the analysis of smaller and weakly chitinized morphological structures such as the labrum and the maxilla.