CELLULAR DEFENSE SYSTEM OF SOME SYNANTHROPIC DIPTERANS INHABITANT
OF BACTERIALLY AGGRESSIVE ENVIRONMENT
T.V. Kind
Department of Entomology, St. Petersburg State University;
e-mail: tatiana.kind@mail.ru
The hemocytic count and defense reaction within 4 families of higher Diptera: Tabanidae, Syrphidae, Muscidae
and Sarcophagidae, whose larvae inhabit bacterially aggressive environment, were investigated. The least
hemocytes types (3) were revealed in Tabanidae and Syrphidae larvae — prohemocytes, plasmatocytes and
prophenoloxydase-containing unstable hyaline cells (oenocytoids). In Sarcophaga crassipalpis and Musca domestica
stable hyaline cells and thrombocytoids or podocytoid-like cells can be added to this set. At the time of
pupariation in Sarcophaga, new generation of prohemocytes is segregated into the hemolymph, which form
small round or spindle-shaped hyaline cells. So, the number of plasmatocyte types in Sarcophaga increase to
six. Typical to Calliphoridae juvenile plasmatocytes in the members of investigated families are absent. Among
the one hemocyte type morphology also can vary, especially in unstable prophenoloxydase hyaline cells. In
Drosophila there are crystal cells containing in the cytoplasm paracrystalloidal inclusions. In Calliphoridae
there are big hyaline cells with homogenous cytoplasm producing circumferential bubbles. Both in Sarcophaga
and Tabanidae they contain in their cytoplasm big globules. However in Sarcophaga they rapidly disintegrate,
while in Tabanidae are maintained unchanged during hours. In Muscidae and Syrphidae prophenoloxydase extrusion
occurs very early and these cells obtain pycnotic nuclei and very liquid cytoplasm with strings of granules.
Thrombocytoids in Musca larvae are represented by big flattened anucleated irregular cytoplasm and «naked
» nuclei and cytoplasmic fragments often with fan-like projections. Plasmatocytes in all species studied are
the cells with pronounced phylopodies. In larvae they contain cytoplasmic catabolic inclusions and in pupa —
fragments of apoptotic tissues. Clearance of hemolymph from alien particles in Sarcophagidae and Muscidae
occur by thrombocytoides, while in Tabanidae by plasmatocyte nodulation. A differing case is Syrphidae where
charcoal injection produce depletion of hemolymph both from particles and all types of hemocytes. So the
specimen of different higher Diptera families can use different schemes of cellular defense reaction.
Key words: Sarcophagidae, Muscidae, Tabanidae, Syrphidae, cellular immunity, hemocytes, phagocytosis,
incapsulation, nodulation
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