No abstract

Mosquito larval ecology is prerequisite for determining the larval abundance and species assemblage in mosquito control program. The study explored the association of five mosquito species with their breeding habitat diversity and species distribution in three selected parks from May to October, 2015. A total of 3217 mosquito larvae were reported from six breeding habitats, namely tree hole, leaf axils, water bottle, tire, drain and coconut shell. The frequency of the three species (Ae. aegypti, Ae. albopictus and Ar. subalbatus) coexistence was higher in tree holes (82.4%) than that of the other coexisting species. Pearson Chi-square result revealed that the association of species was significantly dependent on the breeding habitats. ANOVA further suggested that mosquito density varied across habitats where among the highest density of Cx. quinquefasciatus (3.87 ± 0.22) found in drain, followed by both Ae. albopictus (2.02 ± 0.17) and Ar. subalbatus (0.50 ± 0.09) in tree holes and Ae. aegypti (1.25 ± 0.23) in coconut shell. Cx. tritaeniorhynchus occurred in drain with the least observed density (0.03 ± 0.01). CCA results suggested that Aedes species were likely preferred to oviposit in shaded habitats where pH was associated with Ae. albopictus and dissolved oxygen was with Ae. aegypti and Ar. subalbatus. Culex species were positively associated with the habitats characterizing muddy bottom and emerging vegetation but not with any of the physico-chemical parameters. These findings concluded that ecological factors influence mosquito species to favor their breeding habitats can be helpful in controlling targeted vector species as well as the mosquito borne diseases.

The wild rice gene pool, i.e., AA-genome, in Australia is geographically and genetically distinct from that in Asia. Two distinct taxa are found growing together in northern Australia, Oryza meridionalis (including annual and perennial forms) and an Oryza rufipogon like taxa that have been shown to have a chloroplast genome sequence that is closer to that of O. meridionalis than to O. rufipogon from Asia. Rare plants of intermediate morphology have been observed in the wild despite a reported reproductive barrier between these two species. We now report the resequencing of plants from 26 populations including both taxa and putative hybrids. A comparison of chloroplast and nuclear genome sequences indicated re-combinations that demonstrated hybridisation in both directions. Individuals with intermediate morphology had high nuclear genome heterozygosity consistent with a hybrid origin. An examination of specific genes (e.g., starch biosynthesis genes) revealed the presence of heterozygotes with alleles from both parents suggesting that some wild plants were early generation hybrids. These plants may have low cross-fertility preserving the continuation of the two distinct species. Repeated backcrossing of these rare hybrids to one parent would explain the plants exhibiting chloroplast capture. These observations suggest that reticulate evolution is continuing in wild Oryza populations and may have been a key process in rice evolution and domestication.