What If Gone

Species → Fig wasp

Fig wasp

Ceratosolen spp. (famille Agaonidae)

not assessed by the IUCN, like nearly all fig wasp species — however,…
Extinction risk Not Evaluated
Obligate mutualismTropical forestKeystone speciesPollinatorClimate change
Fig wasp (Ceratosolen spp. (famille Agaonidae))
Photo: Alandmanson, Wikimedia Commons (CC BY 4.0)

What if it disappeared?

Impact High
Over 1 year (Borneo)

A severe drought halted flower production in several fig species, depriving their pollinating wasps — which live only a few days as adults and depend on a nearly continuous supply of receptive figs — of any site to reproduce: several wasp populations went locally extinct, and most had still not returned six months later.

Documented
Detail

Harrison, R.D. (2000). Repercussions of El Niño: drought causes extinction and the breakdown of mutualism in Borneo. Proceedings of the Royal Society B, 267(1446), 911–915.

Each fig species depends almost always on a single wasp species for its pollination, and each wasp can only reproduce in the flowers of its associated fig — an obligate two-way mutualism. The El Niño-related drought broke this cycle by halting flowering in several dioecious fig species; with no receptive figs to lay eggs in, the wasps went locally extinct. Given the high level of endemism among several of these wasps and the extent of the drought, the author notes that some species may have gone extinct entirely, not just locally.

Over 1 year (Borneo)

Without wasps to fertilize them, fig trees aborted their fruit en masse — depriving the forest of one of its only reliable food sources during lean periods; radio-collared sun bears and Bornean bearded pigs were found emaciated or dying during the fruit shortage that followed.

Documented
Detail

Wong, S.T., Servheen, C., Ambu, L. et Norhayati, A. (2005). Impacts of fruit production cycles on Malayan sun bears and bearded pigs in lowland tropical forest of Sabah, Malaysian Borneo. Journal of Tropical Ecology, 21(6), 627–639.

Unlike most tropical trees, which fruit in synchronized, spaced-out pulses ("mast fruiting"), fig trees produce fruit almost continuously thanks to their mutualism with wasps — making them a crucial fallback resource during the long periods when other trees are not fruiting. The removal of this fallback resource, caused by the disappearance of the pollinating wasps, coincides directly with the documented famine episodes among large frugivores in northern Borneo between 1999 and 2000.

By extrapolation

The 1998 episode was temporary and spatially limited — but if fig wasps disappeared permanently over large areas rather than in isolated pockets, the fallback resource that figs represent during lean periods could vanish for good in those areas, with consequences that have never been observed at this scale.

Extrapolated
Detail

Extrapolation à partir de Harrison (2000) et Wong et al. (2005), qui documentent un épisode temporaire et localisé, pas une disparition permanente à grande échelle.

Fig trees are considered a keystone resource precisely because they fruit almost year-round, unlike other tropical trees. No study has been able to observe the consequences of a permanent, widespread loss of pollinating wasps — a scenario necessarily more severe than a one-off drought episode, after which populations were ultimately able to recover through recolonization from unaffected areas.

What's missing to confirm it: No field study documents the consequences of a permanent, widespread extinction of fig wasps — only those, real but temporary and localized, of the 1997-1998 episode.

Documentation

Last verified: August 14, 2026