Constitutive Heterochromatin Differentiation and Evolutionary Divergence of Karyotype in Oriental Anopheles (Cellia)

Analysis of the mitotic karyotype of two clusters of closely related species of oriental Anopheles, the A . balabacensis and A. maculatus complexes, has revealed interspecific differences in the amount and distribution of constitutive heterochromatin, particularly in sex chromosomes. Such a qualitative diagnosis of heterochromatin is useful in identification of these sibling species. The cytological evidence indicates a significant role of heterochromatin in chromosomal evolution of anopheline mosquitoes. The novel heterochromatin differentiation in sex chromosomes suggests an evolutionary role in the process of species divergence. Furthermore, extensive intraspecific variations of sex chromosome heterochromatin have been observed in natural populations of A . dirus A and B, while chromosomal rearrangement is very rare , if not absent. The gross heterochromatin variation may be correlated with variability in vectorial capacity, which may reflect its functional significance in coevolutionary processes

Parasites of larval black flies (Diptera: Simuliidae) in Thailand

Parasites of larval black flies are reported for the first time from Thailand, including mermithid nematodes(Mermithidae), microsporidian fungi (Zygomycota), and the fungus Coelomycidium simulii Debaisieux (Blastocladiomycetes).The following nine species of black flies were infected with one or more parasites: Simulium asakoae, S. chamlongi,S. chiangmaiense, S. fenestratum, S. feuerborni, S. nakhonense, S. nodosum, S. quinquestriatum, and S. tani. The prevalenceof patent infections per host species per season was 0.1–7.1% for mermithids, 0.1–6.0% for microsporidia, and 0.1–3.0% forC. simulii

Nowa Konstytucja Państwa Litewskiego

Digitalizacja i deponowanie archiwalnych zeszytów RPEiS sfinansowane przez MNiSW w ramach realizacji umowy nr 541/P-DUN/201

The insecticide resistance status of malaria vectors in the Mekong region

<p>Abstract</p> <p>Background</p> <p>Knowledge on insecticide resistance in target species is a basic requirement to guide insecticide use in malaria control programmes. Malaria transmission in the Mekong region is mainly concentrated in forested areas along the country borders, so that decisions on insecticide use should ideally be made at regional level. Consequently, cross-country monitoring of insecticide resistance is indispensable to acquire comparable baseline data on insecticide resistance.</p> <p>Methods</p> <p>A network for the monitoring of insecticide resistance, MALVECASIA, was set up in the Mekong region in order to assess the insecticide resistance status of the major malaria vectors in Cambodia, Laos, Thailand, and Vietnam. From 2003 till 2005, bioassays were performed on adult mosquitoes using the standard WHO susceptibility test with diagnostic concentrations of permethrin 0.75% and DDT 4%. Additional tests were done with pyrethroid insecticides applied by the different national malaria control programmes.</p> <p>Results</p> <p><it>Anopheles dirus s.s</it>., the main vector in forested malaria foci, was susceptible to permethrin. However, in central Vietnam, it showed possible resistance to type II pyrethroids. In the Mekong delta, <it>Anopheles epiroticus </it>was highly resistant to all pyrethroid insecticides tested. It was susceptible to DDT, except near Ho Chi Minh City where it showed possible DDT resistance. In Vietnam, pyrethroid susceptible and tolerant <it>Anopheles minimus s.l</it>. populations were found, whereas <it>An. minimus s.l</it>. from Cambodia, Laos and Thailand were susceptible. Only two <it>An. minimus s.l</it>. populations showed DDT tolerance. <it>Anopheles vagus </it>was found resistant to DDT and to several pyrethroids in Vietnam and Cambodia.</p> <p>Conclusion</p> <p>This is the first large scale, cross-country survey of insecticide resistance in <it>Anopheles </it>species in the Mekong Region. A unique baseline data on insecticide resistance for the Mekong region is now available, which enables the follow-up of trends in susceptibility status in the region and which will serve as the basis for further resistance management. Large differences in insecticide resistance status were observed among species and countries. In Vietnam, insecticide resistance was mainly observed in low or transmission-free areas, hence an immediate change of malaria vector control strategy is not required. Though, resistance management is important because the risk of migration of mosquitoes carrying resistance genes from non-endemic to endemic areas. Moreover, trends in resistance status should be carefully monitored and the impact of existing vector control tools on resistant populations should be assessed.</p

FIGURE 6 in Morphotaxonomy of the Simulium (Simulium) tuberosum species group (Diptera: Simuliidae) in Thailand

FIGURE 6. Antennal sheaths of pupae of Simulium tuberosum group from Thailand. A, S. doipuiense cytoform A. B, S. weji. Scale bars = 0.1 mm. Arrow indicates microtubercles

Wolbachia infections of tephritid fruit flies: molecular evidence for five distinct strains in a single host species

Endosymbiotic bacteria of the genus Wolbachia are widespread among arthropods and can induce cytoplasmic incompatibility, thelytokous parthenogenesis, male-killing or feminization in their hosts. Here, we report phylogenetic relationships of Wolbachia in tephritid fruit flies based on wsp gene sequences. We also report, for the first time, five distinct strains of Wolbachia in Bactrocera ascita sp. B. Four of the five Wolbachia strains found in this species were in the same groups as those found in other tephritid fruit flies, suggesting possible horizontal transmission of Wolbachia from other fruit flies into B. ascita sp. B. The unreliability of wsp-specific group primers demonstrated in this study suggests that these primers might be useful only for preliminary identification of Wolbachia. Final determination of group affiliation needs to be verified with wsp sequence data