So small and so rich: diversity of floral resources in miniature Oncidiinae (Orchidaceae) and their relation to pollinators

Abstract

Oncidiinae is one of the most important subtribes among the Neotropical orchids, with an enormous diversity of floral morphology and secretory structures. This subtribe attracts a diverse array of pollinators which explore a variety of floral resources of its flowers. In this paper we provide a detailed investigation of the floral anatomy of 32 species of micro Oncidiinae. We applied histochemical tests in order to determine the diversity of the glands and rewards. The diversity of secretory flower structures and rewards was related to the group of pollinators known for this subtribe. We verified that half of the species (16 species, 50%) secrete oil as a resource, being pollinated by female of solitary bees. Species of some distinct nectar‐secreting genera (four species, 12.5%) are pollinated by a range of nectar‐searching animals. Species of the genus Notylia (four species, 12.5%) release floral perfumes that reward male Euglossini bees. Most of the investigated species (six species, 18.75%) possess osmophores that are involved in pollinator attraction. Two species of Capanemia (6.25%) do not offer any floral reward, suggesting that pollination by food deception is involved. There are strong variations in the anatomy of reward‐producing structures and resources in Oncidiinae. The diversity of floral rewards affects the range of pollinators, which are related to the diversification of this subtribe throughout the Neotropics. The understanding of relationships between Oncidiinae species and their pollinators is crucial to our knowledge of the evolution of pollination systems in this huge plant family represented by the orchids.

Non‐species‐specific pollen transfer and double‐reward production in euglossine‐pollinated Vanilla

“…Lunau 1992; Pansarin & Amaral 2009; Pansarin et al . 2021). During the gathering process, the male euglossines brush the sepal osmophores with their specialized forelegs.…”

“…Furthermore, it is widely accepted that in species pollinated by male euglossines, the fragrance that attracts the bees is a collectable resource (e.g. Lunau 1992;Pansarin & Amaral 2009;Pansarin et al 2021). During the gathering process, the male euglossines brush the sepal osmophores with their specialized forelegs.…”

“…van der Pijl & Dodson 1966; Pansarin & Amaral 2009; Pansarin et al . 2021), how can Vanilla flowers be considered as deceptive; (ii) if male euglossines collect fragrance compounds from sepal osmophores ( e.g . Pansarin & Pansarin 2014; Pansarin 2022), how and why do these long‐tongued hymenopterans perform pollen transfer from euglossinophilous Vanilla if bees need to enter the labellar tube to perform pollination?…”

“…Based these facts, I selected a widely distributed Vanilla species, V. pompona, to answer the following questions: (i) if perfumes are considered a reward for male euglossine bees (e.g. van der Pijl & Dodson 1966;Pansarin & Amaral 2009;Pansarin et al 2021), how can Vanilla flowers be considered as deceptive; (ii) if male euglossines collect fragrance compounds from sepal osmophores (e.g. Pansarin 2022), how and why do these long-tongued hymenopterans perform pollen transfer from euglossinophilous Vanilla if bees need to enter the labellar tube to perform pollination?…”

Interaction between Cymbidium aloifolium and Apis cerana: Incidence of an outlier in modular pollination network of oil flowers

“…The lipidic floral secretion is usually exuded in traces, and yet it seems sufficient in establishing mutualism. Incidentally, the flowers adapted to produce oils also require a specialized plant–pollinator interaction (Pansarin et al, 2020). Being a product of an energy‐demanding biosynthetic pathway, their amount in the flower is small and thus permits fewer floral visits than in those seen in carbohydrate‐rich nectar‐rewarding flowers (Heinrich, 1975; Simpson & Neff, 1981).…”