EGG-SHELLS OF MALLOPHAGANS AND ANOPLURANS (INSECTA, PHTHIRAPTERA) - MORPHOGENESIS OF SPECIALIZED REGIONS AND THE RELATION TO F-ACTIN CYTOSKELETON OF FOLLICULAR CELLS

The egg shells of investigated phthirapterans consist of three basic e lements: an anterior operculum, a main egg shell and a posterior hydro pyle, In some species these elements show further regional specializat ions: bristles and projections that facilitate attachment to feathers of the host, micropyles and aeropylar openings. All of the egg shell s pecializations are formed by distinct subpopulations of follicular cel ls, Staining with rhodamine-conjugated phalloidin has revealed that th ese subpopulations significantly differ in the distribution of microfi laments (F-actin), In this respect four morphological categories of th e follicular cells have been distinguished: (1) cells devoid of proces ses and microvilli, with basal arrays of microfilaments, responsible f or the secretion of a flat chorion; (2) cells devoid of processes and microvilli, separated by intercellular spaces, with basal arrays of mi crofilaments, responsible for the secretion of attachment structures; (3) cells equipped with actin-containing processes, responsible for th e formation of micropyles or aeropyles, and (4) cells equipped with bu ndles of microvilli, responsible for the formation of hydropyles.