Egg morphology of nine species of Pollenia Robineau-Desvoidy, 1830 (Diptera: Calliphoridae).

Egg morphology of nine species of the cluster fly genus Pollenia Robineau-Desvoidy was studied with scanning electron microscopy. Funnel-shaped micropylar area, chorion covered with centrally depressed hexagons, well developed hatching pleats on the dorsal surface encompassing the median area were found in eggs of all species: P. amentaria (Scopoli), P. angustigena Wainwright, P. atramentaria (Meigen), P. labialis Robineau-Desvoidy, P. mayeri Jacentkovsky, P. pediculata Macquart, P. rudis (Fabricius), P. similis (Jacentkovsky), and P. vagabunda (Meigen). Untypical for Calliphoridae, a dual morphological structure of plastron-bearing area is described here for the first time. On the basis of our observations, all species studied share the presence of a plastron respiratory function on the entire surface between the hatching lines. Differences between species were found in the shape of the longitudinal hatching pleats and the proportion between 'island pattern' and 'hexagonal pattern' of their chorionic surface, and in the intensity of perforation of hexagons of the median area. Comparisons of Pollenia egg morphology with that of other representatives of Calliphoridae revealed its unique structure, allowing easy differentiation from other representatives of the family.