LANDSCAPE SURROUNDING HUMAN-SETTLEMENTS AND ANOPHELES-ALBIMANUS (DIPTERA, CULICIDAE) ABUNDANCE IN SOUTHERN CHIAPAS, MEXICO

Landscape characteristics that may influence important components of t he Anopheles albimanus Wiedemann life cycle, including potential breed ing sites, suitable diurnal resting sites, and possible sources of blo od meals, were analyzed at 14 villages in a malarious area of southern Mexico. An. albimanus adults were collected weekly in each village us ing UV-light traps between July 1991 and August 1992. Based on rainfal l, the study was divided into 6 seasonal periods. Villages were consid ered to have high mosquito abundance when >5 mosquitoes per trap per n ight were collected during any 1 of the 6 seasonal periods. The extens ion and frequency of 11 land cover types surrounding villages were det ermined using aerial photographs and subsequently verified through fie ld surveys. Elevation was the main landscape feature that separated vi llages with low and high mosquito abundance. All villages with high mo squito abundance were below 25 m. Transitional and mangrove land cover were found only in the high mosquito abundance group. Flooded areas a s potential breeding sites and potential adult resting sites in unmana ged pastures were significantly more frequent in areas surrounding vil lages with high mosquito abundance. No significant differences in dens ity of cattle and horses were found among village groups. Overall, sur rounding breeding sites located at low elevations in flooded unmanaged pastures seemed to be the most important determinants of An. albimanu s adult abundance in the villages.