Pollination and reproductive biology of Byrsonima pachyphylla and B. verbascifolia (Malpighiaceae)

Abstract

The reproductive biology of Byrsonima pachyphylla and B. verbascifolia in the Brazilian state of Tocantins in the Cerrado biome (Savanna) is described unprecedentedly in this work. This genus belongs to the Malpighiaceae family, which is one of the main sources of resources for bees. Inflorescences of each species were collected for analysis of morphometry and other floral characteristics at Fazenda São Judas Tadeu (10° 48’ 31’’ S and 48° 26’ 52’’ W), located in the municipality of Porto Nacional, Tocantins, Brazil. Floral visitors were observed directly in the field during the peak flowering period. The analysis of the reproductive system was carried out through manual cross-pollination, manual self-pollination, spontaneous self-pollination, apomixis, and natural pollination (control group). The floral characteristics are related to the melittophily syndrome. The bees Centris aenea, C. fuscata, C. sponsa, and C. vittata, were the effective pollinators. Trigona spinipes, Xylocopa frontalis, X. suspecta, Epicharis flava, Augochlora mendax and Apis mellifera performed occasional and sternotribic pollination. Reproductive tests of B. pachyphylla showed fruiting success of 40% by manual cross-pollination and 53% by natural pollination (control group), while through spontaneous self-pollination, manual self-pollination and apomixis there was no reproductive success. For B. verbascifolia, 33% of fruits formed by spontaneous self-pollination, 43% by manual self-pollination, 60% by manual cross- pollination and 63% in the control group, while by apomixis there was no reproductive success. B. pachyphylla is self-compatible and B. verbascifolia is self-incompatible and they both depend on pollinators to ensure their reproductive success