HEMOCYTES OF THE BLOWFLY CALLIPHORA VICINA AND THEIR DYNAMICS DURING LARVAL
DEVELOPMENT AND METAMORPHOSIS
T. V. Kind
Laboratory of Entomology, Biological Institute of St. Petersburg State University;
e-mail: Tatiana.Kind@paloma.spbu.ru
On the basis of in vitro observation of live cells and examination of stained slid :s of larval and
prepupal Calliphora vicina hemolymph, seven types of hemocytes have been detected: p ohemocytes, stable and
unstable hyaline cells, thrombocytoids, spindle cells, larval plasmatocytes, and plas natocytes I-IV, a. The last
representing sequential stages of one cell line differentiation. Prohemocytes are basic cells, from which other
forms of hemocytes derive outside the hemopoietic tissue, i. e. in free hemolymph. At the last larval instar, three
waves of hemopoiesis occur. Either wave tends to increase the genera number of cells and to change the quality of
hemocyte population. The first wave occurs at the close of larva feeding and is acommpanied by increase in the
number of hyaline hemocytes, thrombocytoids and larval plasmatocytes. The second wave of hemopoiesis occurs after
the larva's crop emptying. In this period the main increase of hemocyte population occurs at the expense of
prohemocytes and plasmatocytes I. The most significant (five-fold) explosion of the population of free hemocytes
takes place at the onset of pupariation and correlates with the rise of ecdysone titer. At the first stage of this
peak, the amount of plasmatocytes I sharply increases. Further on these are rapidly differentiated into
plasmatocytes II and III. After the puparium formation, hemocytes are reduced in number. Plasmatocytes III
phagocytose fragrments of destroyed larval tissues, pass to the stage of plasmatocytes IV (macrophages),
and partially settle īn tissues.
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