Abstract Detail

Reproductive Processes

Paudel, Babu [1], Li, Qing-Jun [2].

Pollination Ecology of Himalayan alpine ginger (Roscoea species) in Nepal Himalaya.

The genus Roscoea exhibits the suites of floral traits that would fit pollination by long tongued insects, but previous studies in North-Indochinese clades of Roscoea did not find any pollinators with long tongue that matches with the corolla tube of Roscoea. In this study, we hypothesized that selection by long tongued insect is one of the major driving forces for the evolution of long corolla tubed Roscoea from relatively shorter corolla tubed lineage. To test this hypothesis, we explored the pollination biology of five Himalayan Roscoea species (Roscoea alpina, R. auriculata, R. capitata, R. purpurea and R. tumjensis) that represent diverse floral morphology and phenology together with broad altitudinal distribution range within Himalayan clades of Roscoea. Moreover, based on the preliminary evidence of a long tongued fly as a specialized pollinator of R. purpurea, we made observational and experimental studies of natural selection and coevolution between R. purpurea and a long tongued fly (Philoliche longirostris) across the landscape in Nepal Himalayas. All Himalayan Roscoea species studied here are self-compatible but exhibit pollinator dependent breeding system. Except R. alpina which achieves autonomous selfing by the gradual shrinkage of style, rest four Roscoea species lack autonomous selfing. R. purpurea is pollinated by a specialized pollinator, Philoliche longirostris and thus exhibits specialized pollination system and avoids non specialized pollinator by hiding nectar deep inside the corolla tube so that only a long tongued fly can access the secure nectar. While rest of the Roscoea species depend upon generalized pollinators such as bumblebees (Bombus flavescens and B. haemorrhoidalis), a moth (Macroglossum nycteris), butterflies and even a beetle in the absence of a specialized pollinator. Our result also indicates that corolla length of R. purpurea and tongue length of P. longirostris show significant correlation and well-matched mechanical fit across landscape, in a manner consistent with the Darwin’s hypothesis of reciprocal selection. This study provides some novel information on pollination biology of Roscoea species by discovering the yet unknown effective pollinators. Presence of highly specialized pollinator in R. purpurea (one of the ancestral Roscoea species) may indicate that Roscoea species are originally pollinated by long tongued flies. Moreover, finding of species specific reciprocal selection between corolla length of R. purpurea and proboscis length of P. longirostris suggests that selection by long tongued fly is one of the major driving forces for the evolution of long corolla tubed Roscoea species in the Himalayas.

1 - Yunnan University, Lab of Ecology and Evolutionary Biology, 2# North Cui-Hu Road, Kunming, Yunnan, China
2 - Yunnan University, Lab of Ecology and Evolutionary Biology, 2# North Cui-Hu Road, Kunming, China

Keywords:
Alpine ginger
coevolution
Nepal Himalayas
phenotypic selection
pollination syndrome
Roscoea.

Presentation Type: Oral Paper
Session: 30, Reproductive Processes
Location: Fort Worth Ballroom 7/Omni Hotel
Date: Tuesday, June 27th, 2017
Time: 2:45 PM
Number: 30005
Abstract ID:541
Candidate for Awards:None