Ecologia da Reprodução de Myrcia rostrata DC. e Myrcia tomentosa (Aubl.) DC. (Myrtaceae) em Uberlândia, Minas Gerais

Abstract

Myrtaceae is a very common Neotropical family, its evergreen species and fresh fruits are important food sources for vertebrates and invertebrates, in preserved areas as well as degraded ones, which points out its importance to those ecossistems. We studied the reproductive ecology of two species from one of the biggest genus in this family, Myrcia rostrata DC. and Myrcia tomentosa (Aubl) DC., which are easily found in South American forests and Cerrados. Its small hermafrodite flowers are bee-pollinated, as usual for species of Myrtaceae. Pollen is the sole reward offered to small colonial bees (Trigona, Apis, Augocloropsis). M. rostrata has a “multiple bang” flowering strategy while Myrcia tomentosa has a “pulsed bang” one. The flowering period begins after the first spring rains, a common pattem of many Myrtaceae. Floral buds can remain quiescent for over tliree months waiting for the humidity to increase. Pollination experiments indicated these species are preferencial outcrossing, as many Myrtaceae studied, setting more fruits with outbreeding than with self-pollination. High natural fruit-sets observed for both species denoted adequated pollinating Services at Panga Ecological Reserve. However, the reduced pre-emergent reproductive success values observed mainly for M. tomentosa due to larval herbivory inside floral buds, makes more stuiies necessary to clarify this situation.