Influência de fatores bióticos e abióticos na dispersão aérea do ácaro-vermelho-das-palmeiras Raoiella indica Hirst (Acari: Tenuipalpidae)

Abstract

Aerial dispersion is considered the main strategy used by many mites for long distance movements, and can be influenced by biotic and abiotic factors. However, this subject remains poorly explored among Tenuipalpidae mites. The rapid expansion of the invasive species Raoiella indica Hirst in the American territory raised assumptions about the use of wind as an important means in this process. This work aimed to study the aerial dispersion of R. indica under different wind speeds, developmental stages, sexes, mating status, population densities and food conditions in a wind tunnel in the laboratory; and dispersal potential (heights up to 4.8 m from the ground and distances up to 64 from the planting margin), development stages, sexes and influence of climatic conditions through setting adhesive traps in the field. The laboratory results demonstrate that the increase in wind speed brought on increasing dispersion rate of R. indica and the greater the population density, the less the dispersion. Mating status and food conditions did not have a significant influence. The number of mites caught in the field increased with increasing height and distance up to 48 m, then decreased to 64 m. Atmospheric pressure correlated with the total of captured mites; and rainfall, with the dispersion of males, immatures and eggs. The stage of development in which the highest percentage of dispersion occurred was the adult, and females dispersed more than males, in the field and laboratory. Probably, R. indica reached the tropical region of the Americas dispersing long distances through parts of infested plants, then, it spread quickly through the wind.