Assimetria floral em Centrosema Rotundifolium e seu impacto no número de potenciais polinizadores

Abstract

Floral symmetry is considered an important feature that influences the choice of pollinators. In general, symmetrical flowers are thought to signal more or better resources for pollinators, while asymmetric flowers would indicate developmental problems that could affect the supply of resources. The objectives of the present study were (i) to measure the degree of floating asymmetry in Centrosema rotundifolium (Fabaceae) and (ii) to test experimentally how floral asymmetry affects the number of potential pollinators. Asymmetric flowers are expected to receive fewer potential pollinators than symmetrical flowers. The study was developed in open areas adjacent to the Biosciences Center of the Federal University of Rio Grande do Norte. In the experiment were made blocks with three flowers in which one flower remained with its original symmetry and the others had their symmetry experimentally altered through the partial removal of the left or right petal. Each experimental block was observed during 20 minutes in order to register the floral visitors. Width and height measurements on the right and left side indicate that Centrosema rotundifolium present symmetrical flowers with some degree of floating asymmetry. The main visitors recorded in the period were Lepidoptera and Diptera. Different than expected, the total number of visitors was similar between symmetric or asymmetric flowers, and also did not present differences when Diptera and Lepdoptera were analyzed separately. Our results indicate that floral symmetry may not be used as a signal of quantity and quality of the resource in all plant-pollinator systems.