Spatial Heterogeneity in the Abundance and Fecundity of Arctic Mosquitoes

The abundance of mosquitoes is strongly influenced by biotic and abiotic factors that act on the immature (aquatic) and adult (terrestrial) life stages. Rapid changes in land use and climate, which impact aquatic and terrestrial mosquito habitat, necessitate studying the ecological mechanisms, and their interplay with the changing environment, that affect mosquito abundance. These data are crucial for anticipating how environmental change will impact their roles as pests, disease vectors, and in food webs. We studied a population of Arctic mosquitoes (Aedes nigripes, Diptera: Culicidae) in western Greenland, a region experiencing rapid environmental change, to quantify spatial variation in adult abundance and reproduction. Using sweep nets, we collected about sevenfold more mosquitoes within the town of Kangerlussuaq and within a low‐elevation tundra valley compared to three other tundra locations. Dissections of adult female mosquitoes revealed that only 17% were gravid overall, with a range of 7–43% among sites. If gravid, mosquitoes matured an average of 60 eggs per individual—more in larger females. We found no indication of autogenous egg development. Analyses using our field data indicated that spatial variation in adult fecundity and survival of immatures could each account for a 10‐fold range in the per capita growth of mosquito populations. The availability of vertebrate hosts and aquatic habitat is changing in many parts of the Arctic and can be expected to influence Arctic mosquito abundance. In the Arctic, and elsewhere, life‐history data from natural populations of mosquitoes will significantly aid in understanding controls on the abundance of these globally ubiquitous insects

Decay of escherichia coli in soil following the application of biosolids to agricultural land

The decay of Escherichia coli in a sandy loam soil, amended with enhanced and conventionally treated biosolids, was investigated in a field experiment following spring and autumn applications of sewage sludge. Control soils, without the application of biosolids, were also examined to determine the background indigenous populations of E. coli which are present in the environment. The survival of indigenous E. coli and populations of E. coli applied to soil in biosolids, is assessed in relation to environmental factors influencing pathogen-decay processes in soil

Critical adsorption near edges

Symmetry breaking surface fields give rise to nontrivial and long-ranged order parameter profiles for critical systems such as fluids, alloys or magnets confined to wedges. We discuss the properties of the corresponding universal scaling functions of the order parameter profile and the two-point correlation function and determine the critical exponents eta_parallel and eta_perpendicular for the so-called normal transition.Comment: 22 pages, 5 figures, accepted for publication in PR

Survival of immature Anopheles arabiensis (Diptera: Culicidae) in aquatic habitats in Mwea rice irrigation scheme, central Kenya

BACKGROUND: The survivorship and distribution of Anopheles arabiensis larvae and pupae was examined in a rice agro-ecosystem in Mwea Irrigation Scheme, central Kenya, from August 2005 to April 2006, prior to implementation of larval control programme. METHODS: Horizontal life tables were constructed for immatures in semi-field condition. The time spent in the various immature stages was determined and survival established. Vertical life tables were obtained from five paddies sampled by standard dipping technique. RESULTS: Pre-adult developmental time for An. arabiensis in the trays in the experimental set up in the screen house was 11.85 days from eclosion to emergence. The mean duration of each instar stage was estimated to be 1.40 days for first instars, 2.90 days for second instars, 1.85 days for third instars, 3.80 days for fourth instars and 1.90 days for pupae. A total of 590 individuals emerged into adults, giving an overall survivorship from L1 to adult emergence of 69.4%. A total of 4,956 An. arabiensis immatures were collected in 1,400 dips throughout the sampling period. Of these, 55.9% were collected during the tillering stage, 42.5% during the transplanting period and 1.6% during the land preparation stage. There was a significant difference in the An. arabiensis larval densities among the five stages. Also there was significant variation in immature stage composition for each day's collection in each paddy. These results indicate that the survival of the immatures was higher in some paddies than others. The mortality rate during the transplanting was 99.9% and at tillering was 96.6%, while the overall mortality was 98.3%. CONCLUSION: The survival of An. arabiensis immatures was better during the tillering stage of rice growth. Further the survival of immatures in rice fields is influenced by the rice agronomic activities including addition of nitrogenous fertilizers and pesticides. For effective integrated vector management, the application of larvicides should target An. arabiensis larvae at the tillering stage (early vegetative stage of rice) when their survival in the aquatic habitats is high to significantly reduce them and the larvicides should be long-lasting to have a significant impact on the malaria vector productivity on the habitats

Machine-Readable Data Production by the Federal Government

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68228/2/10.1177_000276427601900402.pd

Health Orientation, Beliefs, and Use of Health Services Among Minority, High-risk Expectant Mothers

This article reports on initial findings of a continuing longitudinal study investigating the relationships of health beliefs as conceptualized by the health belief model and the use of well-baby services among first-time black mothers. The health beliefs of mothers about their babies were measured before the babies were born and during their use of the services at the baby's first and sixth-month visits. Mothers in the sample who became nonusers of the well-baby services were also interviewed. This report describes the results of the first interview of the 662 females who composed the sample for the study, including the following characteristics of a minority, high-risk population: health orientation, health beliefs about their unborn babies, and use of health services. These findings are discussed with implications for community health nursing practice with maternal clients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73774/1/j.1525-1446.1988.tb00553.x.pd