Latitudinal effects on phenology near the northern limit of figs in China

Abstract

The interaction between pollinating wasps and figs is an obligate plant-insect mutualism, and the ca. 750 Ficus species are mainly tropical. Climatic constraints may limit species distributions through their phenology and this seems particularly likely for figs, where phenological mismatches can cause local extinction of the short-lived pollinators. We therefore compared the phenologies of Ficus altissima, F. racemosa and F. semicordata in tropical Xishuangbanna (21°55′N) and subtropical Liuku (25°50′N), SW China, to understand what factors limit fig distributions near their northern limits. All species produced synchronous crops of syconia in Xishuangbanna but production in Liuku was continuous, which may help maintain pollinator populations. However, in general, we found decreased fitness at the northern site: slower syconium development, so fewer crops each year; fewer seeds per syconium (two species); and fewer pollinators and more non-pollinators per syconium, so less pollen is dispersed. This is most easily explained by colder winters, although low humidities may also contribute, and suggests the northern limit is set by temperature constraints on reproductive phenology. If so, the warming predicted for future decades is expected to enhance the fitness of northern populations of figs and, in the longer term, allow them to shift their range limits northwards.

Non‐pollinating cheater wasps benefit from seasonally poor performance of the mutualistic pollinating wasps at the northern limit of the range of Ficus microcarpa

“…In tropical regions, year‐round phenological variation is generally limited, with fig production throughout the year featuring intra‐individual flowering synchrony and inter‐individual asynchrony (Bronstein et al , ). At higher latitudes and at species' range edges, flowering synchrony and wasp and seed production display seasonal fluctuations with concomitant reductions in reproductive success, as measured by seed and female pollinator numbers per fig (Chen et al , ).…”

The plastid genome of a large hemiepiphytic plants Ficus altissima (Moraceae)

“… 2014 ; Chen et al. 2018 ). Adult females of both species share similar biological characteristics but showed different reproductive strategies (Xu et al.…”

Changes in temperature alter competitive interactions and overall structure of fig wasp communities

“…The previous study reported that the survival times of female pollinators were shorter than those of NPFWs, and the short‐lived pollinators is more sensitive to host plant phenology mismatches, so that the community structure of fig wasps is influenced by phenology (Chen et al, 2018, 2020). Our results from multiple regressions show that temperature strongly affects the occurrence and the abundance of all the gall makers (pollinator: Ceratosolen sp.…”

“…However, it is likely that Northern populations are generally ‘slower’ (e.g. longer fig development times and intervals between fruiting) as a direct correlate of decreased temperature (Chen et al, 2018). Therefore, temperature drives these additional factors.…”