SEASONAL AND SPATIAL POPULATION LOADS OF A TROPICAL INSECT - THE CASEOF THE COFFEE LEAF-MINER IN MEXICO

1. The effect of weather fluctuations in a tropical rain forest upon a leaf-miner (the coffee leaf-miner Leucoptera coffeella Guerin-Menevil le (Lepidoptera: Lyonetiidae)) was studied in Veracruz, Mexico. The co mbined effect of temperature and precipitation upon the leaf-miner pop ulations was investigated in coffee plantations located along an eleva tion transect and throughout the annual seasons. The effect of plant d iversity, displayed by the presence or absence of shade trees in coffe e plantations, upon the population loads of the leaf-miner was also in vestigated. 2. The leaf-miner population increased significantly durin g the period of intermediate temperature and low precipitation (spring season). Elevation also affected the population load of the insect: l eaf-miner populations were larger at low elevations (where temperature s are high and precipitation low) than at high elevations. 3. Plant st ructural diversity did not affect the population loads of the leaf-min er. 4. The results indicate that the direct and indirect effects of te mperature and precipitation are significant factors in the population dynamics of the coffee leaf-miner. It is suggested that even moderate fluctuations in climatic conditions in tropical and subtropical region s may also play an important role in the dynamics of tropical insect p opulations, similar to that found in temperate zones where climatic fl uctuations are extreme.