Floral visitors and pollen aspects of Jacaranda mimosifolia D. Don (Bignoniaceae) in an urban landscape

Abstract

The reproductive biology of plants in urban environments remains largely unexplored. This study investigated Jacaranda mimosifolia, a species of great landscape relevance in Brazil, focusing on floral visitor diversity and pollen characteristics. Observations were made in two urban areas with different population densities of the species. Visits from bees (Apis mellifera, Bombus sp., Euglossa sp., Trigona sp.) and hummingbirds (Amazilia sp.) were recorded, with Bombus sp. being the main pollinator. Other visitors acted predominantly as “nectar robbers”. An isolated specimen received fewer visits, suggesting that simultaneous flowering of multiple individuals favors a higher visitation rate. The pollen is tricolpate, prolate, perforate, and dispersed as monads, with an average of 1,126 grains per anther and a pollen-ovule ratio of 56:1, typical of species with biotic pollination. Despite the urban context, J. mimosifolia showed a high visitation rate and viable pollen. However, visitor diversity was lower compared to previous studies, highlighting the need for further research on plant reproduction in anthropized environments.