Biodiv Sci ›› 2010, Vol. 18 ›› Issue (1): 11-18.DOI: 10.3724/SP.J.1003.2010.011

• Original Papers • Previous Articles     Next Articles

The butterfly Pieris rapae resulting in the reproductive success of two transplanted orchids in a botanical garden

Hongfang Zhang1,3, Liqiang Li2, Zhongjian Liu2, Yibo Luo1,2,*()   

  1. 1 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093
    2 The National Orchid Conservation Center, Shenzhen, Guangdong 518114
    3 Graduate School of the Chinese Academy of Sciences, Beijing 100049
  • Received:2009-06-15 Accepted:2009-12-16 Online:2010-01-20 Published:2010-01-20
  • Contact: Yibo Luo

Abstract:

Ex-situ conservation is an effective measure to prevent extinction of species. In order to learn the plant-pollinator relationship in ex situ habitat and shed insights into the ex situ conservation, we studied the pollination system and reproductive strategy of two orchids Ludisia discolor from Wutong Mountains, Shenzhen and Calanthe argenteo-striata from Malipo, Yunnan in the Botanical Garden of the National Orchid Conservation Center (NOCC), Shenzhen, southeastern China in 2007 and 2008. Both species have inflorescences with many white flowers which have spur with a narrow entrance. The butterfly, Pieris rapae, was their solely legitimate pollinators. The pollinaria of L. discolor were carried on the legs of butterflies, while that of C. argenteo-striata on the proboscis. The pollination efficiency in both orchids was high, and the ratio of pollinaria removal to massulae deposition was 1.14:1 and 0.74:1 in L. discolor and C. argenteo-striata, respectively. In 2007 and 2008, fruit set of open pollination in L. discolor was higher than that in C. argenteo-striata, which could be explained by that the former provides rewards to its pollinators while the latter is deceptive, as well as by that the flowering period of L. discolor was synchronized with the abundance of butterflies, which favored the orchid to exploit its pollinators, whereas the flowering period of C. argenteo-striata was lagged behind the outbreak period of butterflies, which made the flowers suffer insufficient pollinator visitation. Both species were self-compatible but there were no spontaneous autogamy or apomixes. The fruit sets of cross-pollination and self-pollination showed no significant difference. Ludisia discolor and C. argenteo-striata grow well after being transplanted to NOCC, and new seedlings were found near parent plants, indicating the population tended to expand, and the ex situ conservation was feasible. It could be predicted that these two orchids have the potential to establish stable populations in NOCC in the future.

Key words: Ludisia discolor, Calanthe argenteo-striata, ex situ conservation, Pieris rapae, specialized pollination, pollination efficiency, reproductive success