Abstract
Haemalopinus suis (Anoplura) and Menacanthus stramineus (Mallophaga) have been cytogenetically analyzed. Both species have 2n = 10, holokinetic chromosomes, and achiasmatic male meiosis. Bivalents orientate with their long axis perpendicular to the spindle fibers at melaphase I, and first anaphase is reductional. As in other species of Phthiraptera, male gametogenesis follows a particular pattern: each cell entering meiosis results in a cyst of 64 (in H. suis) and 32 (in M. stramineus) spermatozoa and 64/32 non-functional cells (=pycnotic nuclei). The results are compared with those previously reported for Phthiraptera, and a new terminology for the different stages of male gametogenesis is proposed. The low chromosome number together with the achiasmatic nature of male meiosis and the mitotic divisions that follow meiosis may restrict the potential for genetic variability. This might be related to the high host specificity of these parasites.
Highlights
Haemalopinus suis ( Anoplura) and Menacanlhus stramineus (Mallophaga) have been cytogenetically analyzed
It became evident that chro- CASTER and CANNON 1920; CANNON1922; mosome characteristics and male gametogenesis SHARMAand MALIK1953)
At In order to get a better understanding of gametopresent, the chromosome number of very few spe- genesis in this order, we have studied the spermatocies is known and the chromosome be- genesis in Menacanthus stramineus (Mallophaga) haviour has been described in most of them, many and in Haematopinus suis (Anoplura)
Summary
I unequal rnLtosLs (32/64) Tertiary spermatids + (32/64) Pycnotic nuclei (32/64) Spermatocytes. 1 unequoL mitosis (32/64) Spermatids + (32/64) Pycnotic nuclei - - - + cell of sulphuric ether was injected into the bag to release the ectoparasites. A total number of 80 specimens were analyzed ( 1 second instar, 36 third instars, 29 adult males and 14 adult females). The material was fixed in 3.1 absolute ethanol: glacial acetic acid and transferred to ethanol 70 % and kept at 4°C. Stramineus were classified according to Hereditus 119 (1993) Different developmental stages of M . stramineus were classified according to Hereditus 119 (1993)
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