Abstract
Floral displays, influencing attractiveness to insects, increase the number of pollinator visits and the efficiency of each visit in terms of pollen exchange and thus affect the plant reproductive success. Here, we conducted an in situ manipulation experiment to investigate whether the floral modifications affect reproductive success in natural orchid populations of Serapias lingua and Serapias vomeracea. We estimated male and female reproductive success of three treatment groups, disassembly of floral tube, cutting of lip, and painting of the callus surface, in terms of pollinaria removed/deposited and fruit production. Results revealed that phenotypic modification had opposite effects on reproductive success of two examine species. Indeed, reproductive success was significantly increased by the detached of the petals and sepals, and decreased, due to callus painting and lip removal, in S. lingua. On the contrary, unmanipulated plants of S. vomeracea showed significantly higher value of pollinaria removed and deposited and fruit set than manipulated ones. The differences between S. lingua and S. vomeracea agree to the different pollination strategy of examined species. S. vomeracea shows shelter imitation strategy, and thus, the disassembly of tunnel‐like corolla does not allow the insects to use the flower as a refuge, while S. lingua is a sexually deceptive orchid and therefore the opening of the flower made more visible callus (visible at a greater distance) increasing the pollinators attraction. This study provides evidence that pollinators were largely sensitive to the experimental modification of the flower phenotype, which is consistent with the presence of significant selection on individual floral characters. Our experimental investigations of the effects of variation in display on pollinator visitation provide insights into the evolution of floral morphology in orchid with shelter imitation strategy.
Highlights
Flower morphology is known for their remarkable stability among individuals of the same species (Minelli, 2015)
The percentage of fruits produced by the natural populations of examined species (29%–32.3%) is within the ranges reported for nectarless orchids of temperate zones (Neiland & Wilcock, 1998) and is consistent with records for previously papers on Serapias populations (Bellusci, Pellegrino, Palermo, & Musacchio, 2010; Pellegrino, Bellusci, & Palermo, 2015; Pellegrino, Musacchio, Noce, Palermo, & Widmer, 2005)
The number of deposited/exported pollinaria, likewise the number of fruits produced, depended on the treatment involved. These results indicate that the detached of the petals and sepals, the excision of the labellum, and the painting of callus had effect on pollinaria removal or fruit production and on pollinator attraction
Summary
Flower morphology is known for their remarkable stability among individuals of the same species (Minelli, 2015). Several studies showed that visual signals than olfactory cues are the major ones involved in pollinator attraction in both types of food-deceptive strategies (Galizia et al, 2005) Another remarkable deceptive mechanism of pollination is sexual deception of male bees and wasps (Kullenberg, 1961). While an unusual type of deceptive pollination mechanism has been observed in the other Serapias species called shelter imitation strategy (Jersáková et al, 2006) In these cases, the sepals, petals, and lateral lobes of the hypochile form a tunnel-like corolla, varying in diameter and depth among taxa, offering a floral tube to the insects in which they use to rest or sleep under bad or rainy weather conditions (van der Cingel, 1995). We carried out flower manipulation experiments in four natural populations of Serapias vomeracea (Figure 1a) and S. lingua (Figure 1b) in Calabria (Italy) and measured male and female reproductive success over an 8-week flowering period
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
