Fluctuating asymmetry (FA) has been proposed as a tool to measure levels of stress experienced by populations of organisms during development. To be of value as a biomarker to highlight conditions at particular sites, it is important that variation in FA is due to environmental (eg pollution) variation and not genetic variation among populations and families, in other words heritability for FA should be very close to zero. A full-sib design was set up in which families of Culex pipiens mosquitoes collected from the field were reared at three different developmental temperatures. The effects of temperature and family on developmental rate, egg to adult survival and four wing morphological measures were assessed. There was both a temperature and a family effect on development rate and survival. Temperature affected all four wing traits, but an influence of family was
Abstract. Fluctuating asymmetry (FA) of bilaterally symmetrical organisms has been introduced as a promising indicator of envi ronmental stress. Stress factors reported to contribute to developmental stability include inbreeding and the presence of resistance genes. In the current study we examined the effect of stress derived from high developmental temperatures, resistance genes and low genetic variation on life history variables and wing FA in Culexpipiens mosquitoes. Three strains were compared: two inbred labo ratory strains sharing a similar genetic background but differing in that one strain contained organophosphate (OP) resistance genes, and a third strain that was an outbred OP resistant field strain recently collected from India. There were no strong and general trends that suggested that the OP resistant lab strain was less fit than the OP susceptible strain, although there were some specific among strain differences for some treatments. Fluctuating asymmetry (FA) of wing traits was higher in the laboratory strains than the field strain, suggesting that inbreeding may cause elevated FA in the study species. There was no evidence that the resistance genes were associated with increased wing FA. Wing FA increased with increasing developmental temperature in females, but the association was less strong in males. There was a significant difference between the sexes in this respect. The results are discussed with refer ence to the value ofFA as a biomonitor of environmental stress.
Botswana has in the recent past 10 years made tremendous progress in the control of malaria and this informed reorientation from malaria control to malaria elimination by the year 2020. This progress is attributed to improved case management, and scale-up of key vector control interventions; indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). However, insecticide resistance, outdoor biting and resting, and predisposing human behaviour, such as staying outdoors or sleeping outdoors without the use of protective measures, pose a challenge to the realization of the full impact of LLINs and IRS. This, together with the paucity of entomological data, inadequate resources and weak community participation for vector control programme implementation delayed attainment of Botswana's goal of malaria elimination. Also, the Botswana National Malaria Programme (NMP) experiences the lack of intersectoral collaborations and operational research for evidence-based decision making. This case study focuses on the vector control aspect of malaria elimination by identifying challenges and explores opportunities that could be taken advantage of to benefit the NMP to optimize and augment the current vector control interventions to achieve malaria elimination by the year 2030 as per the Global Technical Strategy for Malaria 2016-2030 targets. The authors emphasize the need for timely and quality entomological surveillance, operational research and integrated vector management.
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