Karyogamy and meiosis in an Amblyospora sp. (Microspora) in the mosquito Culex salinarius

Abstract

Stages of merogony and sporogony are illustrated in photomicrographs of lacto-aecto-orcein stained smears of an undescribed species of Amblyospora in male Culex salinarius larvae. Karyogamy was observed to take place in diplokaryotic meronts followed by an unusual meiosis-like process in young sporonts. Karyogamy was confirmed by DNA measurements in the nuclei of meronts. DNA measurements at mingling indicate that tetrads may not be formed during “pachytene.” Therefore, structures previously reported to be synaptonemal complexes and meiotic configurations of chromosomes may not actually represent true pachytene chromosomes. It is further shown that karyogamy has been either misplaced or overlooked by numerous investigators and that the behavior of chromosomes during the meiosis-like process was misinterpreted by previous researchers studying chromosomes in microsporidian sporonts.