title: Some like it hot: a differential response to changing temperatures by the malaria vectorsAnopheles funestusandAn. gambiaes.l.
abstract: BACKGROUND
  With the possible implications of global warming, the effect of temperature on the dynamics of malaria vectors in Africa has become a subject of increasing interest. Information from the field is, however, relatively sparse. We describe the effect of ambient temperature over a five-year period on the dynamics ofAn. funestusandAn. gambiaes.l., collected from a single village in southern Mozambique where temperatures varied from a night-time minimum of 6 °C in the cool season to a daytime maximum of 35 °C in the hot season.
  
  
  RESULTS
  Mean daily air temperatures varied from 34 °C to 20 °C and soil temperatures varied from 26 °C to 12 °C. Diurnal variation was greatest in the cooler months of the year and were greater in air temperatures than soil temperatures. During the study 301, 705 femaleAn. funestuswere collected in 6,043 light-trap collections, 161, 466 in 7,397 exit collections and 16, 995 in 1,315 resting collections. The equivalent numbers forAn. gambiaes.l. are 72,475 in light-traps, 33, 868 in exit collections and 5,333 from indoor resting collections. Numbers of mosquito were greatest in the warmer months. Numbers ofAn. gambiaes.l. went through a one hundredfold change (from a mean of 0.14 mosquitoes a night to 14) whereas numbers ofAn. funestusmerely doubled (from a mean of 20 to 40 a night). The highest environmental correlations and mosquito numbers were between mean air temperature (r2= 0.52 forAn. funestusand 0.77 forAn. gambiaes.l.). Numbers of mosquito collected were not related to rainfall with lags of up to four weeks. Numbers of both gravid and unfedAn. gambiaecomplex females in exit collections continued to increase at all temperatures recorded but gravid females ofAn. funestusdecreased at temperatures above 28 °C. Overall the numbers of gravid and unfedAn. funestuscollected in exit collections were not correlated (p= 0.07). For an unknown reason the number ofAn. gambiaes.l. fell below monitoring thresholds during the study.
  
  
  CONCLUSIONS
  Mean air temperature was the most important environmental parameter affecting both vectors in this part of Mozambique. Numbers ofAn. gambiaes.l. increased at all temperatures recorded whilstAn. funestusappeared to be adversely affected by temperatures of 28 °C and above. These differences may influence the distribution of the vectors as the planet warms.
authors.affiliation: Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Rua da Junqueira, Global Health and Tropical Medicine, GHTM, Lisbon, Portugal; MOZDAN (Mozambican-Danish Rural Malaria Initiative), Morrumbene, Inhambane Province, Mozambique; Centre for Health Research and Development, University of Copenhagen, Copenhagen, Denmark; National Institute of Health, Maputo, Mozambique.
authors.forename: Jacques Derek
authors.initials: JD
authors.lastname: Charlwood
keywords: Anopheles funestus; Anopheles gambiae s.l.; Exit collection; Gravid; Light-trap; Mozambique; Population dynamics; Rainfall; Temperature; Unfed