Ecological variations in adult life table attributes of Aedes aegypti (L.) from the desert and coastal regions of India.

The ecological variation in biological and adult life-table attributes of two populations of Aedes aegypti (Diptera: Culicidae) from the desert (Jodhpur) and coastal (Kolkata) regions of India are assessed to understand the reproductive and survival strategies. The results showed that females lived longer than males in both strains. The desert strain was more r-strategist because of its higher intrinsic rate of increase (rm  = 0.23), finite rate of increase (λ = 1.25), lower life expectancy of males (7.9 days) and females (14.4 days), mean generation time (T = 19.2 days) and doubling time (DT = 3.0 days). However, there was no difference in net reproductive rate (R0 ) between the desert and coastal strains. The coastal strain showed a longer female life expectancy (22.0 days) than the desert strain (14.4 days). However, the fecundity (eggs/female/day) was lower in the coastal strain (11.4) than in the desert strain (15.1). Conclusively, the desert (Jodhpur) strain is adapted to a better r-strategy than the coastal (Kolkata) strain of Ae. aegypti, which might be helpful to flourish in harsh environmental conditions. This study may provide accurate predictions of Ae. aegypti population dynamics for vector management.

Prevalence of mouthpart sensilla and protease producing symbiotic gut bacteria in the forensic fly Chrysomya megacephala (Fabricius, 1794): Insight from foraging to digestion.

The blow fly, Chrysomya megacephala (Fabricius, 1794) is a globally prevalent forensically important species that helps to estimate accurate postmortem interval since the death. This fly occasionally causes cutaneous myiasis and transmits several pathogenic bacteria. To understand their ability of corpse detection and digestion of protein-rich meal, the present study describes the mouthpart sensilla and assessment of protease producing symbiotic gut bacteria. Scanning electron microscopy (SEM) showed the prevalence of trichoid sensilla (Tr), basiconic sensilla (Ba) and microtrichia (Mr) on labellar lobes, haustellum and maxillary palps of mouthparts. Bacterial particles of both rod (small and large) and spherical shaped were detected in the gut of C. megacephala using SEM. The bacterial density was higher on the foregut and midgut in comparison to the hindgut. From 72 bacterial isolates, 10 isolates from the foregut region showed considerable protease-producing efficacy ranging between 3.98 - 6.83 GHR and 9.73 - 34.68 U/ml protease. Among these, the most promising protease-producing bacterial isolate showed 16S rDNA sequence similarity (99.85%) with Chryseobacterium artocarpi DNA. This bacterium was the first report from flies. The findings of the study might help in better understanding of the role of sensilla in host perception and foregut symbiotic bacterial association in protein digestion in C. megacephala.

Life table, survival and fecundity parameters of Aedes albopictus (Diptera: Culicidae) strains from desert and coastal regions of India.

The Asian tiger mosquito, Aedes albopictus (Skuse, 1895) is the anthropophilic and day-biter mosquito, residing in peridomestic habitats and is responsible for vector-borne diseases, i.e., chikungunya and dengue. The knowledge of mosquito life demographics is very important to provide a foundation for a successful vector control program. In the present study, a comparative adult life table, survival, and fecundity parameters were evaluated on desert (Jodhpur, Rajasthan) and coastal (Kolkata, West Bengal) strains of Aedes albopictus (Diptera: Culicidae) from India under the standard laboratory conditions. The results showed significant differences between these strains for the life expectancy of males, fecundity (total eggs/cohort and eggs/female life span), oviposition days, intrinsic rate of increase (rm), finite rate of increase (λ), and doubling time (DT). Female mosquitoes lived longer than the males in both strains. Significant differences were observed in the net reproductive rate (R0) between Kolkata and Jodhpur strains. The coastal (Kolkata) strain showed a longer male life expectancy (5.6 days) than the desert strain (4.0 days). However, the fecundity (eggs/female lifespan) was higher in Kolkata (360.2) than the Jodhpur strain (229.7). The Kolkata strain showed higher R0, rm, λ, and the lower T, DT than the Jodhpur strain. Conclusively, the results indicate that the coastal strain of Ae. albopictus is more r-strategist than the desert strain. This study may help in the precise prediction of Ae. albopictus population dynamics surviving in these geographical areas for vector management.

Ion Conduction and Its Activation in Hydrated Solid Polyelectrolyte Complexes.

For the first time, temperature-dependent conductivities at constant water content for a series of solid polyelectrolyte complexes with varying mixing ratios of anionic poly(sodium 4-styrene sulfonate) and poly(diallyldimethylammonium chloride) are presented. For water absorption, the samples are first equilibrated at an ambient temperature and at fixed relative humidity (RH). During the conductivity measurements, the so achieved water content of the samples is kept constant. At all of the hydration levels, the dc conductivities of the hydrated polyelectrolyte complexes (PEC) display Arrhenius behavior with activation enthalpies that are significantly lower than those of dry complexes. The activation enthalpy decreases linearly with water content. The lower activation enthalpies in case of hydrated as compared to dried complexes are attributed to a lowering of the energy barriers for ion motion. Finally, it is shown that the temperature-dependent conductivity spectra at constant water content obey the time-temperature superposition principle. Additionally, temperature-dependent conductivities at constant water content are compared to data sets determined in a separate study with constant RH at all of the temperatures. For the latter case, the influence of the type of alkali ion is also considered. Using the broad variety of data sets, the influences of water content and temperature on the conductivity mechanism can be separated from each other.