Telipogon peruvianus (Orchidaceae) Flowers Elicit Pre-Mating Behaviour in Eudejeania (Tachinidae) Males for Pollination

Abstract

Several neotropical orchid genera have been proposed as being sexually deceptive; however, this has been carefully tested in only a few cases. The genus Telipogon has long been assumed to be pollinated by male tachinid flies during pseudocopulatory events but no detailed confirmatory reports are available. Here, we have used an array of methods to elucidate the pollination mechanism in Telipogon peruvianus. The species presents flowers that have a mean floral longevity of 33 days and that are self-compatible, although spontaneous self-pollination does not occur. The flowers attract males of four tachinid species but only the males of an undescribed Eudejeania (Eudejeania aff. browni; Tachinidae) species are specific pollinators. Males visit the flowers during the first few hours of the day and the pollination success is very high (42% in one patch) compared with other sexually deceptive species. Female-seeking males are attracted to the flowers but do not attempt copulation with the flowers, as is usually described in sexually deceptive species. Nevertheless, morphological analysis and behavioural tests have shown an imperfect mimicry between flowers and females suggesting that the attractant stimulus is not based only on visual cues, as long thought. Challenging previous conclusions, our chemical analysis has confirmed that flowers of Telipogon release volatile compounds; however, the role of these volatiles in pollinator behaviour remains to be established. Pollinator behaviour and histological analyses indicate that Telipogon flowers possess scent-producing structures throughout the corolla. Our study provides the first confirmed case of (i) a sexually deceptive species in the Onciidinae, (ii) pollination by pre-copulatory behaviour and (iii) pollination by sexual deception involving tachinid flies.

Don’t forget the flies: dipteran diversity and its consequences for floral ecology and evolution

“…Rewardless Andean orchids in the genera Trichoceros and Telipogon have long been suspected of sexual deception, using male tachinid flies as dupes (van der Pijl and Dodson 1966). Recent work by Martel et al (2016) demonstrated that the flowers of Telipogon peruvianus attract male Eudejeania tachinid flies as pollinators. Chemical and behavioral analyses revealed that these flowers mimic both the cuticular hydrocarbon blend used by female Eudejeania flies to attract males and the yellow ray florets of the aster flowers upon which male flies seek mates in montane habitats (Martel et al 2019).…”

A literature review of the pollination strategies and breeding systems in Oncidiinae orchids

“…Floral scents are not solely employed to attract male Euglossini bees. These fragrances are equally important on mechanisms based on deception, acting as a fake signal to mislead insects looking for food or sexual partners (Aguiar 2014;Martel et al 2016). In some cases, these compounds are unnoticeable to the human nose.…”

Looks matter: changes in flower form affect pollination effectiveness in a sexually deceptive orchid

“…In principle, the form of the lip might act as a visual signal to mate-searching males and also ensure the correct alignment between the body of the pollinator and the reproductive parts of the plant (Kullenberg, 1961(Kullenberg, , 1973Phillips et al, 2014;De Jager & Peakall, 2015;G€ ogler et al, 2015;Martel et al, 2016). Selection on the lip form could be thus imposed through both the sensory preferences of the pollinator and the mechanical fit between the pollinator and the lip (De Jager & Peakall, 2015).…”