POLARIZATION, KINETOCHORE MOVEMENTS, AND BIVALENT STRUCTURE IN THE MEIOSIS OF MALE MANTIDS

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Abstract
Bouquet formation, kinetochore movements, and bivalent structure in [male] meiosis are described for the following spp. Stagmomantis Carolina, Para-tenodera sinensis, Liturgousa annulipes, Chroeradodis rhombicollis, and Angela guianensis. Bouquet formation is a special process, distinct from relic orientation, and involves special activities of "chromosome ends, division centers, and nuclear membrane. The initial separation of homologous kinetochores in meiotic bivalents is independent of the spindle and appears to be autonomous to the kinetochores. The pre-metaphase poleward movement of kinetochores and the stretching of the meiotic chromosomes are due in part to elongation of the spindle and in part to another factor or factors which may include kinetochore repulsion, kinetochore-center attraction, and activity of the half spindle components. Three separable factors in the association of homologues in meiotic bivalents are distinguished: 1) lateral attraction, independent of chiasmata and variously localized in different bivalents; 2) terminal attraction, independent of chiasmata in certain bivalents and in others following chiasma terminalization; and 3) chiasmata. Closely related species, and different bivalents within a species, vary in which of these factors are operative. Males of Stagmomantis Carolina from Virginia and from Barro Colorado Island, C. Z., otherwise identical, differ in the time of spindle formation relative to the stage of bivalent development.