Pollinator Behaviour on a Food‐Deceptive Orchid Calypso bulbosa and Coflowering Species

Abstract

Food deception as a pollination strategy has inspired many studies over the last few decades. Pollinator deception has evolved in many orchids possibly to enhance outcrossing. Food-deceptive orchids usually have low pollinator visitation rates as compared to rewarding species. They may benefit in visitations from the presence (magnet-species hypothesis) or, alternatively, absence of coflowering rewarding species (competition hypothesis). We present data on pollinator visitations on a deceptive, terrestrial orchid Calypso bulbosa, a species with a single flower per plant and whose flowering period partly overlaps with rewarding, early flowering willows (Salix sp.) and later-flowering bilberry (Vaccinium myrtillus). When surveying inactive bumblebee queens on willows in cool weather, about 7% of them carried Calypso pollinia. Most common bumblebee species appeared to visit and thus pollinate Calypso. Bumblebees typically visited one to three Calypso flowers before flying away, providing some support for the outcrossing hypothesis. We conclude that, regarding the pollinations strategy, both magnet-species and competition hypotheses have a role in the pollination of Calypso, but on different spatial scales. On a large scale rewarding species are important for attracting pollinators to a given region, but on a small scale absence of competition ensures sufficient pollination rate for the deceptive orchid.

Ecological factors affecting the fitness of the threatened orchid Anacamptis robusta (Orchidaceae): Habitat disturbance, interactions with a co‐flowering rewarding orchid and hybridization events

“…Anacamptis coriophora can attract pollinators through scent and nectar reward, and its visitation rate is higher than nectarless species (Smithson 2006). For this reason, despite A. coriophora may act as magnet species for A. robusta , our results show that individuals of A. robusta with a higher fruit set were found the furthest away from individuals of A. coriophora, indicating a probable reduction in pollinators caused by the A. coriophora attracting mechanisms, as reported for other species (Tuomi et al 2015). These results support that there are only a few hybrids in the study area, despite the high abundance of both parental species.…”

Male and female reproductive success in natural and anthropogenic populations of Malaxis monophyllos (L.) Sw. (Orchidaceae)

“…These results agree with the phenology of potential pollinators from the Mycetophyllide family which have the first peak of appearance in June, when they become active after the winter-spring lull, and before the autumn flush associated with the intensified appearance of fungus fruiting bodies (Rindal et al 2009). Such data confirm that flowering time might be the most important trait affecting the fruit set, especially for orchids which do not offer any reward to pollinators (Sabat & Ackerman 1996;Tuomi et al 2015).…”

Can honey bees discriminate between floral-fragrance isomers?

“…In an ecological scenario, pollinators typically visit two to five flowers of a same deceptive orchid before abandoning the inflorescence (Aguiar, 2014;Jersáková and Johnson, 2006;Johnson et al, 2004;Tuomi et al, 2015). This would be closer to absolute conditioning, as the animal would experience the same stimulus several times, without a different stimulus in between.…”