Biodiversity Pattern of Mosquitoes in Southeastern Senegal, Epidemiological Implication in Arbovirus and Malaria Transmission

Abstract

The composition, density, diversity, and temporal distribution of mosquito species and the influence of temperature, relative humidity, and rainfall on these data were investigated in 50 sites across five land cover classes (forest, savannah, barren, village, and agriculture) in southeastern Senegal. Mosquitoes were collected monthly in each site between June 2009 and March 2011, with three people collecting mosquitoes landing on their legs for one to four consecutive days. In total, 81,219 specimens, belonging to 60 species and 7 genera, were collected. The most abundant species were Aedes furcifer (Edwards) (Diptera: Culicidae) (20.7%), Ae. vittatus (Bigot) (19.5%), Ae. dalzieli (Theobald) (14.7%), and Ae. luteocephalus (Newstead) (13.7%). Ae. dalzieli, Ae. furcifer, Ae. vittatus, Ae. luteocephalus, Ae. taylori Edwards, Ae. africanus (Theobald), Ae. minutus (Theobald), Anopheles coustani Laveran, Culex quinquefasciatus Say, and Mansonia uniformis (Theobald) comprised ≥10% of the total collection, in at least one land cover. The lowest species richness and Brillouin diversity index (HB = 1.55) were observed in the forest-canopy. The urban-indoor fauna showed the highest dissimilarity with other land covers and was most similar to the urban-outdoor fauna following Jaccard and Morisita index. Mosquito abundance peaked in June and October 2009 and July and October 2010. The highest species density was recorded in October. The maximum temperature was correlated positively with mean temperature and negatively with rainfall and relative humidity. Rainfall showed a positive correlation with mosquito abundance and species density. These data will be useful for understanding the transmission of arboviruses and human malaria in the region.

Keywords: arbovirus; biodiversity; land cover class; malaria; mosquitoes.

Fig. 1.

Study area in Kédougou, Senegal. This figure is modified from Diallo et al. (2012b).

Fig. 2.

Individual-based rarefaction curves for mosquitoes collected in different land cover classes, Kédougou, Senegal during June 2009 through March 2010 and May 2010 through March 2011.

Fig. 3.

Cluster analysis using the Morisita and Jaccard indexes between land cover classes in Kédougou, June 2009 through March 2010 and May 2010 through March 2011.

Fig. 4.

Monthly distribution of mosquito diversity indices, mean temperature (°C), relative humidity (%), and rainfall (mm) in Kédougou, June 2009 through March 2010 and May 2010 through March 2011. Error bars in the Brillouin diversity indices indicate 95% confidence intervals. Abundance is measured as mean number of mosquitoes collected per person per evening.