[Behavior of holokinetic chromosomes in the spermatogenesis of bugs]

Chromosomes were studied on the spermatogonial metaphase and on different stages of meiotic division in males of Eurydeme geblery Kol. and E. ventrale Kol. The set of male chromosomes of the above species involves six pairs of autosomes and an XY sex pair, which is commonly the case in Pentatomidae. In the spermatogenesis, division types are reductional for autosomes and equational for sex chromosomes in the first metaphase; but the situation is quite opposite in the second metaphase. The sex chromosomes of bugs undergo a "touch and go" pairing on the metaphase plate of the second spermatocyte, prior to segregating to opposite poles in the anaphase that follows. No constrictions occur along all the chromosomes at mitosis. This, combined with their behaviour at mitosis, may suggest that, likely as in other Hemiptera, the chromosomes are holokinetic. Nevertheless it is of interest to note that in meiosis the chromosomes behave as telocentric. This replacement of the holokinetic orientation by the telokinetic one in the meiosis of some organisms with diffuse centromere is supposed to depend on the phenomen called "construction of the kinetic activation".