It is hypothesized that some host-mediated effects (e.g. host species, deciduous vs. evergreen host) have been key in developing phenological asynchrony in mistletoes. However, few empirically based comprehensive studies of the reproductive phenology of mistletoe have been undertaken, and the extent to which host-mediated effects influence reproductive phenology remains poorly understood.
In a study published in Journal of Plant Ecology, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) investigated the reproductive phenology (flowering and fruiting) of a generalist mistletoe, Dendrophthoe pentandra, for two years to evaluate traits and to explore if host-mediated effects contribute to the phenological asynchrony of the mistletoe.
The researchers conducted fieldwork for two consecutive years (2018 to 2019) in secondary forests with some level of human disturbance in Xishuangbanna, SW China. They studied the reproductive phenological patterns of the generalist mistletoe at plot, site, and host species levels in tropical seasonal rainforests, to understand phenology and phenological asynchrony.
The results showed that D. pentandra has a unimodal seasonal reproductive phenology, where flowering and fruiting coincided with the dry and rainy seasons, respectively. The first flowering date (a phenological event), was significantly influenced by crown area of mistletoe clump and light exposure. Plot, site, and host species were shown to significantly influence mistletoe phenology.
Surprisingly, asynchrony in reproductive phenology did not significantly change when related to the number of host species.
“Our study demonstrated that the number of host species may not necessarily be beneficial for the phenology of a generalist mistletoe to maintain diffuse coevolution,” said Prof. ZHANG Ling of XTBG.
ZHANG Ling Ph.D
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
The haustoria, flowers, and fruits traits of Dendrophthoe pentandra (Image by LI Manru)