Ionopsis utricularioides, (Sw.) Lindl. (Sw.) Lindl.

Aguiar, João Marcelo Robazzi Bignelli Valente, Ferreira, Gabriel de Souza, Sanches, Patricia Alessandra, Simões Bento, Mauricio José & Sazima, Marlies, 2021, What pollinators see does not match what they smell: Absence of color-fragrance association in the deceptive orchid Ionopsis utricularioides, Phytochemistry (112591) 182, pp. 1-10 : 2

2.1. What is the scent composition of I. utricularioides ?

Eighteen different volatile components were found in the flowers of I. utricularioides . Floral volatile composition and concentrations of each compound varied between individuals ( Table 1 ), as also recorded for several other deceptive orchids (Delle-Vedove et al., 2011; Dormont et al, 2014, 2019; Juillet and Scopece, 2010; Salzmann et al., 2007a, 2007b; Salzmann and Schiestl, 2007). As expected by the bee-pollination deceptive mechanism of I. utricularioides ( Aguiar and Pansarin, 2019) , many compounds in the orchid’ s fragrance are known to be important in pollinators’ attraction in other bee-pollinated plants, such as phenylacetaldehyde ( Knauer and Schiestl, 2015; Theis, 2006; Waelti et al., 2008) and limonene, one of the most common volatiles emitted by flowers ( Benelli et al., 2017; Erasto and Viljoen, 2008; Knudsen et al., 1993). β- ocimene, the major compound found in the fragrance of I. utricularioides , with an average emission of 52.6 ± 13.7 ng μl 1 (mean ± S.E.) and occurring in 80% of the sampled individuals ( Table 1 ), is also very common in rewarding flowers pollinated by insects (Farr´e-Armengol et al., 2017; Knudsen et al., 2006). Farr´e-Armengol et al. (2017) proposed an interesting hypothesis that, given its recurrence and abundance in floral fragrances, β- ocimene would act as a general global floral signal to many plants in a community. In this context, other minor compounds could ensure the scent specificity needed for pollination (Farr´e-Armengol et al., 2017), as pollinators, especially bees, can detect minor changes in floral fragrance composition ( Locatelli et al., 2016; Raguso, 2008). In the generalized food deceptive pollination context of I. utricularioides ( Aguiar and Pansarin, 2019) , β- ocimene could, thus, act as a global sign to attract pollinators, and bees could also perceive the variability derived from the other minor compounds of this orchid’ s scent. However, further behavioral or electrophysiological studies are needed to corroborate this hypothesis.