Moths Visiting the Flowers of the OrchidPlatanthera japonica

Abstract

There are approximately 24,500 orchid species already reported, and they are one of the most diverse angiosperm families (Dressler, 2005). Orchids are biologically complex, and as such are proposed as an appealing way to study many of our most fundamental questions on biology. Orchid flowers allow researchers to study the development and evolution of pollination biology and flower forms, as they showcase a great example of the close relationship between plants and their pollinators (Duttke et al., 2012). The orchid’s floral complexity is one of the key factors in the rapid species radiation (Waterman and Bidartondo, 2008). For example, some of the features found on orchids—such as nocturnally emitted fragrance, whitish colorations, and long narrow spurs—are clues to pollination by moths (Hapeman and Inoue, 1997). Despite the great interest in orchid biology and diversity, little is known about their pollination biology in many taxa (Widmer et al., 2000). Therefore, it is primarily important to increase the observations of orchid pollinations in order to expand our understanding of the specificity of orchid-pollinator interactions. It is, unfortunately, challenging to directly observe pollination events in orchids. This is because during a flowering season, the proportion of flowers visited is generally low (Neiland and Wilcock, 1995). The long life-span of individual flowers combined with low population densities con tri butes to making pollination observation particularly time-consuming and tedious (Wid mer et al., 2000). It appears that Platanthera has become extremely diversified, both in its pollination system and its floral form (Hapeman and Inoue, 1997). Platanthera flow ers range in color from purple or orange to green and white. They may have a “fringed” appearance due to the elaborate dissections of the petals and labellum. All species have a nectar spur on the lip, the length of which may be greater than 4cm in some taxa (Hapeman and Inoue, 1997). Though most of the species are pollinated by pyralid and noctuid moths, pollination by mosquitoes, bees, butterflies, beetles and flies have also been observed (Inoue, 1983; Inoue, 1985; Hapeman and Inoue, 1997). The diverse pollination systems within Pla tan thera corresponds to most of the Orchidaceae’s non-deceptive pollination types (Van Der Pijl and Dodson, 1966). Phylogenetic analysis suggests that Pla tanthera’s basal condition can involve generalized pollination by pyralid and noctuid moths, while hawkmoth (Sphigidae) polli nation—which requires only minimal modification from the green to the greenish-white floral syndrome found in most 78 ENTOMOLOGICAL NEWS