The Karyotype of the parasitoid Chelonus insularis cresson (Hymenoptera, braconidae, cheloninae).

The Karyotype of chelonus insularis (Hymenoptera, Braconidae Cheloninae) is described. The males show an haploid number of seven chromosomes and the females a diploid number of fourteen chromosomes, confirming haplo-diploid sex determination. Comparisons of these results with karyotypes of other species of the same family were done and a possible mechanism involved in the karyotype evolution of this species is discussed

Genetic characterization of some neoponera (Hymenoptera: Formicidae) populations within the foetida species complex

The foetida species complex comprises 13 Neotropical species in the ant genus Neoponera Emery (1901). Neoponera villosa Fabricius (1804) , Neoponera inversa Smith (1858), Neoponera bactronica Fernandes, Oliveira & Delabie (2013), and Neoponera curvinodis (Forel, 1899) have had an ambiguous taxonomic status for more than two decades. In southern Bahia, Brazil, these four species are frequently found in sympatry. Here we used Bayesian Inference and maximum likelihood analyses of COI and 16S mtDNA sequence data and conventional cytogenetic data together with observations on morphology to characterize sympatric populations of N. villosa, N. inversa, N. bactronica, and N. curvinodis. Our results showed marked differences in the karyotype of these ants. Both N. curvinodis and N. inversa have chromosome number of 2n = 30. Their chromosome composition, however, is distinct, which indicates that N. curvinodis is more closely related to N. bactronica. These four species clustered into three distinct groups. The close relationship between N. bactronica and N. curvinodis deserves further investigation since it has not been fully resolved here. Our results confirm that N. inversa, N. villosa, N. bactronica + N. curvinodis indeed represent four distinct taxa within the foetida species complex

Chromosome numbers and C-banding in two wasp species of the genus Polistes (Hymenoptera Polistine, Polistini)

A cytogenetic study was performed on 2 waps species of the tribe polistini, including the determination of chromosome number and the detection of thterochromatin by C-banding technique.Polistes (Epicnemius) cinerascens presents n=27, 2n=54 chromosomes of the meta- sub- and acrocentric types; heterochromatin has a varied distribution: in and around the centromere in chromosomes: sometimes on one of the majority of the arms or on almost throughout the entire chromosomes.Poliste (Aphanilopterus) versicolor versicolor presents n=31, 2n=62 meta- and submetacentric chromosomes; heterochromatin is distributed on one of the chromosome arms.Une étude cytogénétique a été développée chez deux espèces de guêpes de la tribu Polistini comprenant la détermination du nombre de chromosomes et aussi la détection de l'hétérochromatine par l'emploi de la technique de la bande C.Polister (Epicnemius) cinerascens possède n=27, 2n=54, comprenant des chromosomes des types meta- subet acrocentriques; l'heterochromatine a une localisation diverisifiée: dans le centromére au long du chrosmosome.Polistes (Aphanilopterus) versicolor versicolor possède n=31, soit 2n=62 chromosomes des type meta-et submétacentriques; l'hétérochromatine et distribuée sur l'un des bras du chromosome

Hsc-FA and NOR bandings on chromosomes of the giant ant Dinoponera lucida Emery, 1901 (Hymenoptera: Formicidae)

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Estrogen deficiency leads to apoptosis in dopaminergic neurons in the medial preoptic area and arcuate nucleus of male mice

The aromatase knockout (ArKO) mouse is unable to synthesize estrogens. Immunohistochemical studies on active caspase-3 and tyrosine hydroxylase (TH) revealed apoptosis of dopaminergic neurons in the medial preoptic area (MPO) and arcuate nucleus (Arc) of the hypothalamus of 1-year-old (1yo) male ArKO mice while no active caspase-3 was detected in wild type (WT). Furthermore, the number of TH-positive cells in the MPO and caudal Arc was significantly decreased in 1yo ArKO compared to WT. RNase protection assays support the presence of apoptosis in 1yo ArKO hypothalamus, revealing an up-regulation of pro-apoptotic genes: FASL, FADD, and caspase-8. Concomitantly, the ratio of bcl-2-related anti-apoptotic genes to pro-apoptotic genes in the hypothalamus of 1yo ArKO mice was significantly down-regulated. Previously, we have reported that no such changes were observed in the hypothalamus of female ArKO mice. Thus, we have provided direct evidence that estrogen is required to maintain the survival and functional integrity of dopaminergic neurons in the MPO and Arc of male, but not female mice

Integration of a B chromosome into the A genome of a wasp, revisited.

A previous study showed that in the haplodiploid solitary wasp Trypoxylon albitarse, most individuals carry one B chromosome per haploid genome, the same dosage as the standard (A) chromosomes, indicating a possible regularization of B-chromosome meiotic behaviour and its integration into the A genome. In a new sampling, we have analysed 15 populations (including 9 out of the 10 previously analysed) to test the evolution of this integration process. The new results provide a direct report of the invasion process in the Porto Firme population, where B frequency has dramatically increased in only four generations. In the populations from the Viçosa region, however, B frequency has remained stable, although the principal B type, the metacentric one, has increased in frequency at the expense of the acrocentric one in several populations. The implications of these new results on the hypothesis of the integration of these B chromosomes, as regular members of the A genome, are discussed