ABSTRACT The dependence of commercial crops on pollinators is closely related to their reproductive strategies and has direct impacts on production yields. Fruit production of Averrhoa carambola, the star fruit, is highly dependent on bee pollination. This distylous species may exhibit monomorphism associated with self-compatibility, a condition that may influence its degree of dependence on pollinators for fruit set. We evaluated the floral morphology and mating system of A. carambola and their relationships with pollinator dependence in an apparently pin-monomorphic orchard to address the following questions: Is the orchard indeed pin-monomorphic? Is the orchard self-compatible? Are pollination services sufficient to reach maximum productivity? Is fruit set related to the number of visits? We investigated floral morphometrics, mating system, and pollination following standard methods of plant reproduction research. The orchard exhibited pin-monomorphism and self-compatibility. Herkogamy strongly impaired spontaneous self-pollination, emphasizing the relevance of pollinators to crop yield. Considering that Apis mellifera was the only pollinator observed, and that the orchard showed pollen limitation, we recommend the implementation of pollinator management strategies. Additional studies will be needed to assess if the atypical distyly observed here occurs in other situations.

ABSTRACT Flowers of species of Senna are very morphologically diverse, however, nothing has been reported regarding variation in the presence of a unicarpellate gynoecium, which is characteristic of the group. This study reports the occurrence of a bicarpellate gynoecium in two enantiostylous species of Senna in an area of dry forest (Caatinga) in NE Brazil. Observations of floral morphology and estimates of the proportions of floral morphs in the populations were performed. The species produce three floral types: left (L), right (R) and bicarpellate (B). The proportion of these floral morphs were similar in the populations of Senna macranthera var. micans, but the number of B flowers in populations of S. trachypus was lower than that recorded for L and R flowers. The occurrence of this morphological variation may be related to enhancing pollen capture in both species; in S. trachypus, this variation may also be related to reducing florivory by caterpillars that were observed eating sexual elements of the flowers.

Na literatura tem sido amplamente registrado que aranhas Thomisidae predam visitantes florais de várias espécies de planta. Neste estudo nós apresentamos observações de Croton selowii Baill. (Euphorbiaceae), uma espécie monóica, abrigando aranhas Thomisidae em uma área de restinga de Pernambuco, Brasil. A espécie é visitada por invertebrados de várias ordens e vários deles são predados pelas aranhas, principalmente espécies de Diptera. As aranhas apresentaram um comportamento de esfregar as pernas dianteiras dentro das flores, o que pode ser interpretado como uma estratégia de camuflagem das pernas. Croton selowii parece representar um bom sítio de forrageamento para essas aranhas, pois possui um sistema de polinização generalista, sendo visitado por ampla gama de invertebrados e floresce em um período de baixa disponibilidade de flores na área.

In the literature it has been extensively mentioned that crab spiders (Araneae: Thomisidae) prey on floral visitors of several plant species. Here we present observations of Croton selowii Baill. (Euphorbiaceae), a monoecious species harboring individuals of crab spiders in an area of coastal vegetation of Pernambuco state, Brazil. The species is visited by several invertebrate orders, and some of them were preyed upon by the spiders, mainly Diptera species. The spiders rubbed the forelimbs within the flowers, which may constitute a strategy to camouflage these structures. Croton selowii seems to represent a suitable foraging site for the spiders, because it has a generalist pollination system (thus being visited by a wide range of invertebrate species) and blooms in a period of low flower resource availability in the area.