Fly pollination in Cypripedium
Charles Darwin used orchid flowers as model systems to explain the evolution of functional morphology and adaptations. However, Darwin did not accept C. K. Sprengel’s concept of pollination-by-deceit, in which floral stimuli attracts pollinators but the flower fails to reward the pollinator. Recent theories insist that floral mimesis or deception appears to drive speciation in the majority of lineages within the terrestrial Orchidaceae. Historically, the genus Cypripedium has been regarded as a model lineage of nonrewarding orchid flowers that tempoirarily trap their pollinators but the majority of species studied, to date, are bee-pollinated. However, China is the center of biodiversity for Cypripedium and the southwestern mountains of China represent the hotspot of diversity for endemic Cypripedium spp. Recent studies indicate that, at least, five Cypripedium species found there are pollinated by flies exploiting a suite of attractant characters known as myophily. Previously, we described a new mode of deceptive pollination in Cypripedium fargesii (This is part of my PhD project). This nectarless, critically endangered endemic requires fungus-eating (mycophagic) flies for pollination/fertilization of seeds. Unlike most deceptive orchids, the flower is not the only deceptive organ. In fact, the blackish hairy spotted leaves combine with the floral pigmentation patttern and musty floral scent lure flies that, under normal circumstance, would feed on the fungal exudates of infected vegetation. Theoretically, the leaf and flower mimesis of fungus-infected foliage probably represents a “bridge” between generalist food mimesis, in most Cypripedium spp., and full mimicry of fungal fruiting bodies (sporocarps). Based on molecular evidence, Cypripedium fargesii has three-five “sister species” so closely related that they are all now placed in Section Trigonopedia, all found in the same, but broad, southwestern hotspot in China. All of these species have similar pigmentation patterns on their leaves and flowers as C. fargesii. Field and lab work is required to show whether the same mode of deceptive pollination persists throughout Section Trigonopedia? Do all species attract the same fly species? Based on my PhD dissertation project of C. fargesii, from 2012, I began to conduct a morphometric, quantitative and biochemical study to compare pollination modes within the Trigonopedia lineage to determine evolutionary trends.
Charles Darwin used orchid flowers as model systems to explain the evolution of functional morphology and adaptations. However, Darwin did not accept C. K. Sprengel’s concept of pollination-by-deceit, in which floral stimuli attracts pollinators but the flower fails to reward the pollinator. Recent theories insist that floral mimesis or deception appears to drive speciation in the majority of lineages within the terrestrial Orchidaceae. Historically, the genus Cypripedium has been regarded as a model lineage of nonrewarding orchid flowers that tempoirarily trap their pollinators but the majority of species studied, to date, are bee-pollinated. However, China is the center of biodiversity for Cypripedium and the southwestern mountains of China represent the hotspot of diversity for endemic Cypripedium spp. Recent studies indicate that, at least, five Cypripedium species found there are pollinated by flies exploiting a suite of attractant characters known as myophily. Previously, we described a new mode of deceptive pollination in Cypripedium fargesii (This is part of my PhD project). This nectarless, critically endangered endemic requires fungus-eating (mycophagic) flies for pollination/fertilization of seeds. Unlike most deceptive orchids, the flower is not the only deceptive organ. In fact, the blackish hairy spotted leaves combine with the floral pigmentation patttern and musty floral scent lure flies that, under normal circumstance, would feed on the fungal exudates of infected vegetation. Theoretically, the leaf and flower mimesis of fungus-infected foliage probably represents a “bridge” between generalist food mimesis, in most Cypripedium spp., and full mimicry of fungal fruiting bodies (sporocarps). Based on molecular evidence, Cypripedium fargesii has three-five “sister species” so closely related that they are all now placed in Section Trigonopedia, all found in the same, but broad, southwestern hotspot in China. All of these species have similar pigmentation patterns on their leaves and flowers as C. fargesii. Field and lab work is required to show whether the same mode of deceptive pollination persists throughout Section Trigonopedia? Do all species attract the same fly species? Based on my PhD dissertation project of C. fargesii, from 2012, I began to conduct a morphometric, quantitative and biochemical study to compare pollination modes within the Trigonopedia lineage to determine evolutionary trends.
Calanthe yaoshanensis and its pollinators (Ren., et al., 2014)
New species Calanthe yaoshanensis and its pollination biology
The genus Calanthe with about 150 species, is globally distributed in tropical and subtropical areas. Lepidopteran pollination is to be expected in Calanthe, namely its floral syndrome is likely adapted to pollination by moths or butterflies. Butterflies pollination is conformed by limited observations in Calanthe, and large-sized bee pollination is also recorded. The biodiversity hotspot of the mountains of southwestern China is one of the centers of diversity for this genus. It is here we find most alpine Calanthe species are no spur or short spurred, which contrary to lepidopteran pollination hypothesis. In this study, we focus on a nectarless alpine C. yaoshanensis to address what pollinators are pollinated for it, and to elucidate its pollination mechanism.
The genus Calanthe with about 150 species, is globally distributed in tropical and subtropical areas. Lepidopteran pollination is to be expected in Calanthe, namely its floral syndrome is likely adapted to pollination by moths or butterflies. Butterflies pollination is conformed by limited observations in Calanthe, and large-sized bee pollination is also recorded. The biodiversity hotspot of the mountains of southwestern China is one of the centers of diversity for this genus. It is here we find most alpine Calanthe species are no spur or short spurred, which contrary to lepidopteran pollination hypothesis. In this study, we focus on a nectarless alpine C. yaoshanensis to address what pollinators are pollinated for it, and to elucidate its pollination mechanism.
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Insect pollination and breeding system of medicinal/crop plants in southwestern China
I and my lab member mainly focus on edible and medicinal crops of Yunnan in southwestern China. In this region, species diversity is extremely high presumed to be a center of origin/variation for economically important plants used for food and medicine. Our long-term goals are to study these plant and insect taxa to understand the patterns and consequences of pollinator deficit. We ask the following questions: 1) Do these plants (domesticated vs. wild) depend on pollinators to reproduce? 2) What are the most important pollinators of these crops and/or their wild relatives? 3) How important are wild pollinator species for maximizing yield in Chinese crops compared to domesticated Apis species? |
