What pollinators see does not match what they smell: Absence of color-fragrance association in the deceptive orchid Ionopsis utricularioides
Author
Aguiar, João Marcelo Robazzi Bignelli Valente
* & Programa de P´os-Graduaçao ˜ em Ecologia, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, 13083 - 865, Brazil
Author
Ferreira, Gabriel de Souza
Senckenberg Centre for Human Evolution and Palaeoenvironment (HEP) at the Eberhard Karls Universit ¨ at Tübingen, Sigwartstr. 10, 72076, Tübingen, Germany
Author
Sanches, Patricia Alessandra
Universidade de S ˜ ao Paulo, Escola Superior de Agricultura “ Luiz de Queiroz ” (ESALQ), Departamento de Entomologia e Acarologia, Piracicaba, SP, 13418 - 900, Brazil & Department of Environmental Systems Science, Swiss Federal Institute of Technology (ETH Zürich), 8092, Zürich, Switzerland
Author
Simões Bento, Mauricio José
Universidade de São Paulo, Escola Superior de Agricultura “ Luiz de Queiroz ” (ESALQ), Departamento de Entomologia e Acarologia, Piracicaba, SP, 13418 - 900, Brazil
Author
Sazima, Marlies
Departamento de Botânica, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, 13083 - 865, Brazil
text
Phytochemistry
2021
112591
2021-02-28
182
1
10
http://dx.doi.org/10.1016/j.phytochem.2020.112591
journal article
10.1016/j.phytochem.2020.112591
1873-3700
8291529
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.