More examples of breakdown the 1:1 partner specificity between figs and fig wasps

Botanical Studies - Tập 62 - Trang 1-12 - 2021
Hui Yu1,2,3, Yaolin Liao1, Yufen Cheng1, Yongxia Jia1, Stephen G. Compton4
1Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, China
2Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
3Centre for Plant Ecology, CAS Core Botanical Gardens, Guangzhou, China
4School of Biology, University of Leeds, Leeds, UK

Tóm tắt

The obligate mutualism between fig trees (Ficus, Moraceae) and pollinating fig wasps (Agaonidae) is a model system for studying co-evolution due to its perceived extreme specificity, but recent studies have reported a number of examples of trees pollinated by more than one fig wasp or sharing pollinators with other trees. This will make the potential of pollen flow between species and hybridization more likely though only few fig hybrids in nature have been found. We reared pollinator fig wasps from figs of 13 Chinese fig tree species and established their identity using genetic methods in order to investigate the extent to which they were supporting more than one species of pollinator (co-pollinator). Our results showed (1) pollinator sharing was frequent among closely-related dioecious species (where pollinator offspring and seeds develop on different trees); (2) that where two pollinator species were developing in figs of one host species there was usually one fig wasp with prominent rate than the other. An exception was F. triloba, where its two pollinators were equally abundant; (3) the extent of co-pollinator within one fig species is related to the dispersal ability of them which is stronger in dioecious figs, especially in small species. Our results gave more examples to the breakdown of extreme specificity, which suggest that host expansion events where pollinators reproduce in figs other than those of their usual hosts are not uncommon among fig wasps associated with dioecious hosts. Because closely related trees typically have closely related pollinators that have a very similar appearance, the extent of pollinator-sharing has probably been underestimated. Any pollinators that enter female figs carrying heterospecific pollen could potentially generate hybrid seed, and the extent of hybridization and its significance may also have been underestimated.

Tài liệu tham khảo

Berg CC (1990) Reproduction and evolution of Ficus (Moraceae): traits connected with the adequate rearing of pollinators. Mem New York Bot Gard 55:169–185

Condit IJ (1950) An interspecific hybrid in Ficus. J Hered 41:165–168

Harrison RD (2005) Figs and the diversity of tropical rainforests. Bioscience 55:1053–1064

Janzen DH (1979) How to be a fig. Ann Rev Ecol Syst 10:13–51

Jousselin E, van Noort S, Berry V, Rasplus RY, Rønsted N, Erasmus JC et al (2008) One fig to bind them all: host conservatism in a fig wasp community unraveled by conspeciation analyses among pollinating and nonpollinating fig wasps. Evolution 62:1777–1797

Lopez-Vaamonde C, Rasplus JY, Weiblen G, Cook JM (2001) DNA-based phylogenies of fig wasps: partial cocladogenesis between pollinators and parasites. Mol Phylogenet Evol 21:55–71

Patel A, Hossaert-McKey M, McKey D (1993) Ficus-pollinator reserch in India: past, present and future. Curr Sci 65:243–253

van Noort S, Ware AB, Compton SG (1989) Pollinator-specific volatile attractants released from the figs of Ficus burtt-davyi. S Afr J Sci 85:323–324

Wiebes JT (1993) Agaonidae (Hymenoptera Chalcidoidea) and Ficus (Moraceae): fig wasps and their figs, XI (Blastophaga) s.l. Proc Kon Ned Akad Wet Ser C 96:347–367

Yu H, Zhao NX, Chen YZ, Deng Y, Yao JY, Ye HG (2006) Phenology and reproductive model of a common fig (Ficus hirta Vahl.) in Guangzhou. Bot Stud 47:435–441

Zhang T, Jandér CK, Huang JF, Wang B, Zhao JB, Miao BG et al (2021) The evolution of parasitism from mutualism in wasps pollinating the fig, Ficus microcarpa, in Yunnan Province. China PNAS 118:e2021148118

Zhou ZH, Gilbert MG (2003) Moraceae Flora of China 5:21–73