Electron microscopic observations on wound-healing in larvae of the mosquito Armigeres subalbatus (Diptera : Culicidae)

The wound-healing processes in the mosquito Armigeres subalbatus(Coquillett )were observed with electron microscopy. The initial reaction involved woun d contraction and aggregation of injured surface tissues, cell debris and m ovement of granulocytes toward the wound. Granulocytes first aggregated aro und the surface of the wound and many filamentous filopodia protruded to co nnect with cytoplasmic strands. These strands were then interconnected to f orm a network coagulum resulting in wound closure to prevent body fluid los s. Granulocytes lysed on the wound-site and released granular materials aro und the wound, inducing localized clot formation. These results suggested t hat wound-healing in this mosquito species involved both humoral and cellul ar reactions. The latter reaction involved the movement of plasmatocytes to the basement membrane of the epidermis beneath the wound-site and epitheli al cells regeneration. Our observations revealed that wound-healing in A. s ubalbatus involves the wound contraction, formation of a temporary cellular clump, scar formation, basement membrane formation, and reepithelializatio n. The larvae neither discarded the wound scar nor secreted a new cuticle u ntil the next molting. Based on the ultrastructural observations, it is sug gested that the wound-healing reaction in A. subalbatus was probably a typi cal response employed by other members of the family Culicidae.