Noctuid moths as potential hybridization agents for Platanthera orchids

Abstract

abstract. Zoophilous flowering plants communicate with pollinators to ensure pollen transfer. Pin-pointing which species are effective pollinators is not only essential to better understand plant-pollinator networks, but equally so to better understand the potential of hybridization in plant systems, such as in orchids. As a case study, we studied two sympatric populations of the congeneric orchids Platanthera bifolia and P. chlorantha in order to assess their nocturnal pollinators by checking which moth species carried pollinaria, and of which orchid species. Moths carrying Platanthera pollinaria were photographed and identified. The carried pollinaria were identified and counted, and their attachment position on the moth's head was scored. Based on these observations we show that three species of noctuid moths visited the Platanthera inflorescences. Although Noctua pronuba visited P. chlorantha, only Cucullia umbratica and Autographa gamma turned out to be potential pollinators for both orchid species. As such, we here demonstrate that the latter two noctuids have high potential to facilitate hybridization among these two orchid species, especially so in sympatric populations.

Peer Review #2 of "Characterization of sympatric Platanthera bifolia and Platanthera chlorantha (Orchidaceae) populations with intermediate plants (v0.1)"

“…Indeed, a noctuid species, namely Cucullia umbratica, was observed as a pollinator of intermediate individuals (Claessens et al 2008). The same species was also observed by us, visiting and pollinating intermediate as well as P. bifolia and P. chlorantha individuals, in the same populations as studied in this article (Esposito et al 2017).…”

Characterization of sympatricPlatanthera bifoliaandPlatanthera chlorantha(Orchidaceae) populations with intermediate plants

“…Indeed, a noctuid species, namely Cucullia umbratica , was observed as a pollinator of intermediate individuals ( Claessens, Gravendeel & Kleynen, 2008 ). The same species was also observed by us, visiting and pollinating intermediate as well as P. bifolia and P. chlorantha individuals, in the same populations as studied in this article ( Esposito, Merckx & Tyteca, 2017 ).…”

Nectar composition in moth-pollinated Platanthera bifolia and P. chlorantha and its importance for reproductive success

“…Our interest stems from the fact that this species pair is a suitable model system to study co-evolutionary processes. The main differences between the two Platanthera species are column structure and connected with this structure's pollinaria attachment (tongue attachment in P. bifolia and eye attachment in P. chlorantha) as well as the ethological mechanism, resulting from the differential attraction of pollinators due to differences in floral scent chemistry (Nilsson 1983(Nilsson , 1985Esposito et al 2017). These differences result in moths that belong to the noctuids being better adapted to pollinate P. chlorantha, while sphingids are the main pollinators of P. bifolia, although both Platanthera species may share the main pollinators (Nilsson 1983).…”