Cytogenetic Features of Human Head and Body Lice (Phthiraptera: Pediculidae).

The genus Pediculus L. that parasitize humans comprise two subspecies: the head lice Pediculus humanus capitis De Geer and the body lice Pediculus humanus humanus De Geer. Despite the 200 yr of the first description of these two species, there is still a long debate about their taxonomic status.

Complementary sex determination in the parasitic wasp Diachasmimorpha longicaudata.

We studied the sex determination in Diachasmimorpha longicaudata, a parasitoid braconid wasp widely used as biological control agent of fruit pest tephritid flies. We tested the complementary sex determination hypothesis (CSD) known in at least 60 species of Hymenoptera. According to CSD, male or female development depends on the allelic composition of one sex locus (single-locus CSD) or multiple sex loci (multiple-locus CSD).

Heterochromatin characterization and ribosomal gene location in two monotypic genera of bloodsucker bugs (Cimicidae, Heteroptera) with holokinetic chromosomes and achiasmatic male meiosis.

Members of the family Cimicidae (Heteroptera: Cimicomorpha) are temporary bloodsuckers on birds and bats as primary hosts and humans as secondary hosts. Acanthocrios furnarii (2n=12=10+XY, male) and Psitticimex uritui (2n=31=28+X1X2Y, male) are two monotypic genera of the subfamily Haematosiphoninae, which have achiasmatic male meiosis of collochore type. Here, we examined chromatin organization and constitution of cimicid holokinetic chromosomes by determining the amount, composition and distribution of constitutive heterochromatin, and number and location of nucleolus organizer regions (NORs) in both species.

The significance of cytogenetics for the study of karyotype evolution and taxonomy of water bugs (Heteroptera, Belostomatidae) native to Argentina.

Male meiosis behaviour and heterochromatin characterization of three big water bug species were studied. Belostoma dentatum (Mayr, 1863), Belostoma elongatum Montandon, 1908 and Belostoma gestroi Montandon, 1903 possess 2n = 26 + X1X2Y (male). In these species, male meiosis is similar to that previously observed in Belostoma Latreille, 1807.

Cytogenetic study in a mutant of Triatoma infestans (Hemiptera: Reduviidae) carrying a spontaneous autosomal fusion and an extra chromosome.

Triatomainfestans (2n = 20 A + XY, male) is a blood-sucking bug and the most important vector of Chagas disease in the Southern Cone countries. A cytogenetic analysis of 14 individuals from the Argentine Gran Chaco has revealed the presence of a naturally heterozygous for an autosomal fusion. The fusion heterozygote (2n = 19 A + 1 extra chromosome + XY, male) presented an autosomal trivalent, 8 bivalents, the X and Y sex univalents, and a minute extra chromosome at meiosis I.