Contribution of thrips to seed production in Habenaria radiata, an orchid morphologically adapted to hawkmoths

Specialized petal with conspicuously fringed margin influences reproductive success in Habenaria radiata (Orchidaceae)

“…Our field studies showed that no thrips‐mediated fruit set occurred in the populations investigated in this study, although thrips occasionally deliver pollen grains to H. radiata stigmas (Shigeta & Suetsugu, 2020). By contrast, the H. radiata pollinarium, or multiple pollinaria, were observed to be attached to the compound eyes of the hawkmoths and skippers, confirming that they are effective pollinators (Figure 1d,e).…”

“…We predicted that the complex lip morphology of H. radiata had evolved to increase its pollinator‐mediated reproductive success. Habenaria radiata is pollinated primarily by nocturnal hawkmoths, Theretra japonica and Theretra nessus (Sphingidae) (Shigeta & Suetsugu, 2020) and diurnal skipper butterflies, Parnara guttata , Polytremis pellucida , and Pelopidas mathias (Hesperiidae) (Ikeuchi et al, 2015; Suetsugu & Tanaka, 2014). The hawkmoths typically hover on the flowers without landing on them, whereas the skippers perch on the flowers when seeking nectar (Ikeuchi et al, 2015; Suetsugu & Tanaka, 2014).…”

Morphological and Genetic Diversities of Habenaria radiata (Orchidaceae) in the Kinki Area, Japan

“…The complex shape of the lips suggests that the lips of H. radiata act as visible markers or landing places. It is known that two skipper species (Pelopidas mathias and P. guttata) and one hawkmoth (Theretra japonica) visit H. radiata flowers and transfer pollinia by attaching them on their head [4][5][6]. We recorded flower visitors with one video camera and found that the hawkmoth (Theretra oldenlandiae) visited several flowers and seemed to suck nectar from spurs while hovering, without landing on the flowers (Movie S1).…”

“…The Japanese name for this plant "Sagi-sou" (meaning an egret plant), which is derived from the lip morphology, and it has been described in many literature works and novels in Japan. The complex lip shape may play a role in attracting pollinators such as skippers and hawkmoths [4][5][6]. It is suggested that H. radiata carries local variation in flower shape in different habitats [7], however quantitative and genetic analyses of the variation have not been performed before.…”