Ecologia e biologia reprodutiva de Evolvulus pterocaulon (Convolvulaceae) condicionada pelo ambiente no Cerrado

Abstract

The Cerrado is the second largest biome in the national territory, and it is an important phytophysiognomy that has been suffering from degradation caused by human activity. Anthropogenic changes generate changes in the landscape, creating different environmental conditions, such as temperature, humidity and sunlight, causing important ecological interactions to be affected, such as pollination, responsible for the maintenance of local communities. Convolvulaceae is an important family for maintenance of plant communities and their pollinators, so in this work we evaluate the ecology and reproductive biology of Evolvulus pterocaulon conditioned by different environments of the Cerrado. For that, five specific objectives were elaborated: (1) to investigate the phenology of the species; (2) to determine the biology and phenology of the flower; (3) to understand reproductive biology; (4) to find out if there is a difference in natural fruiting conditioned by floral visitors present in four nearby areas; (5) to know the role of floral visitors. The species showed annual flowering during the rainy season and highly synchronized among individuals. E. pterocauolon flowers have anthesis from 6:30 am with pollen already available, but the stigma is receptive only after about 30 min. and flower lasts until 12:00. The dish-shaped corolla with exposed and easily accessible pollen makes the flower generalist and accessed by several insects. The reproductive system was self-incompatible, making the species dependent on pollinators for its fruiting. Bees were considered effective pollinators for their proper behavior and their high frequency in flowers. Flies were considered occasional pollinators for not always touching the stigma, and butterflies were considered unsuitable for pollination because of their rare visits and lack of contact with the reproductive parts. The species proved to be able to fruit and maintain itself both in natural areas and in altered environments, sustaining in both the same guild of pollinating insects.