PolinizaÃÃo de Tabebuia Impetiginosa e Jacaranda Rugosa (Bignoniaceae) e o efeito de Pilhadores no seu sucesso reprodutivo no Parque Nacional do Catimbau

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

studied in the National Park of Catimbau, emphasizing the activity of nectar robbers on their reproductive success. The mechanism of stigma closure was also investigated in these and in other three species of this family, Anemopaegma laeve, Arrabidaea limae and Jacaranda irwinii. T. impetiginosa and J. rugosa are self-incompatible species and depends on mediumto large-sized bees, mainly from the tribes Centridini and Euglossini, to be pollinated. Trigona spinipes and species of Xylocopa were the principal nectar robbers, attacking 70% of the flowers. The effect of nectar robbers on the reproductive success of the plants was assessed in experiments where nectar amount was controlled and in experiments where flowers were protected against nectar robbers. Experimental nectar removal, simulating the activity of nectar robbers, resulted in brief flower visits, while addition of artificial nectar doubled the time of a flower visit. The reduction of nectar availability to visitors should, consequently, increase the number of flower visits and flights performed among conspecific individuals, leading to higher rate of cross-pollination. Flowers protected against nectar robbers set more fruits than unprotected flowers, mainly because of the activity of Trigona spinipes. The natural low fruit set observed in the studied population was a result of the destructive behavior of T. spinipes and of the high rate of geitonogamy, associated to the definitive stigma closure after deposition of self or cross conspecific pollen grains. Definitive stigma closure was related to deposition of conspecific viable pollen grains in four of the five species studied

ASSUNTO(S)

pilhadores fechamento estigmÃtico nectar robbers pollination centridini euglossini stigma closure abelhas ecologia bees polinizaÃÃo centridini parque nacional do catimbau euglossini catimbau national park

ACESSO AO ARTIGO

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