The resurgence of malaria in highland regions of Africa, Oceania and recently in South
America underlines the importance of the study of the ecology of highland mosquito vectors of
malaria. Since the incidence of malaria is limited by the distribution of its vectors, the purpose of
this PhD thesis was to examine aspects of the ecology of Anopheles mosquitoes in the Andes of
Ecuador, South America. A historical literature and archival data review (Chapter 2) indicated
that Anopheles pseudopunctipennis transmitted malaria in highland valleys of Ecuador prior to
1950, although it was eliminated through habitat removal and the use of chemical insecticides.
Other anopheline species were previously limited to low-altitude regions, except in a few
unconfirmed cases. A thorough larval collection effort (n=438 attempted collection sites) in all
road-accessible parts of Ecuador except for the lowland Amazon basin was undertaken between
2008 - 2010 (Chapter 3). Larvae were identified morphologically and using molecular techniques
(mitochondrial COl gene), and distribution maps indicated that all five species collected
(Anopheles albimanus, An. pseudopunctipennis, Anopheles punctimacula, Anopheles oswaldoi
s.l. and Anopheles eiseni) were more widespread throughout highland regions than previously
recorded during the 1940s, with higher maximum altitudes for all except An. pseudopunctipennis
(1541 m, 1930 m, 1906 m, 1233 m and 1873 m, respectively). During larval collections, to
characterize species-specific larval habitat, a variety of abiotic and biotic habitat parameters were
measured and compared between species-present and species-absent sites using chi-square tests
and stepwise binary logistic regression analyses (Chapter 4). An. albimanus was significantly
associated with permanent pools with sand substrates and An. pseudopunctipennis with gravel
and boulder substrates. Both species were significantly associated with floating cyanobacterial mats and warmer temperatures, which may limit their presence in cooler highland regions.
Anopheles punctimacula was collected more often than expected from algae-free, shaded pools
with higher-than-average calculated dissolved oxygen. Anopheles oswaldoi s.l., the species
occurring on the Amazonian side of the Andes, was associated with permanent, anthropogenic
habitats such as roadside ditches and ponds. To address the hypothesis that human land use
change is responsible for the emergence of multiple highland Anopheles species by creating
larval habitat, common land uses in the western Andes were surveyed for standing water and
potential larval habitat suitability (Chapter 5). Rivers and road edges provided large amounts of
potentially suitable anopheline habitat in the western Andes, while cattle pasture also created
potentially suitable habitat in irrigation canals and watering ponds. Other common land uses
surveyed (banana farms, sugarcane plantations, mixed tree plantations, and empty lots) were
usually established on steep slopes and had very little standing water present. Using distribution
and larval habitat data, a GIS-based larval habitat distribution model for the common western
species was constructed in ArcGIS v.l 0 (ESRI 2010) using derived data layers from field
measurements and other sources (Chapter 6). The additive model predicted 76.4 - 97.9% of the
field-observed collection localities of An. albimanus, An. pseudopunctipennis and An.
punctimacula, although it could not accurately distinguish between species-absent and speciespresent
sites due to its coarse scale. The model predicted distributional expansion and/or shift of
one or more anopheline species into the following highland valleys with climate warming:
Mira/Chota, Imbabura province, Tumbaco, Pichincha province, Pallatanga and Sibambe,
Chimborazo province, and Yungilla, Azuay province. These valleys may serve as targeted sites
of future monitoring to prevent highland epidemics of malaria. The human perceptions of
malaria and mosquitoes in relation to land management practices were assessed through an interview-based survey (n=262) in both highlands and lowlands, of male and female land owners
and managers of five property types (Chapter 7). Although respondents had a strong
understanding of where the disease occurs in their own country and of the basic relationship
among standing water, mosquitoes and malaria, about half of respondents in potential risk areas
denied the current possibility of malaria infection on their own property. As well, about half of
respondents with potential anopheline larval habitat did not report its presence, likely due to a
highly specific definition of suitable mosquito habitat. Most respondents who are considered at
risk of malaria currently use at least one type of mosquito bite prevention, most commonly bed
nets. In conclusion, this interdisciplinary thesis examines the occurrence of Anopheles species in
the lowland transition area and highlands in Ecuador, from a historic, geographic, ecological and
sociological perspective