"There is genuine paradox and real poetry lurking in the fig, with subulties to exercise an enquiring mind and wonders to uplift an aesthetic one .. But the fig is only one out of millions that all have the same Darwinian grammar and logic - albeit the fig story is amongst the most satisfyingly intricate in evolution." Richard Dawkins, Climbing Mount Improbable (1996)
Mutualism is a close relationship between two individuals of the same or different species where both are benefited. The relationship between species of the genus Ficus and wasps of the family Agaonidae is obligate mutualism- both species require the other for survival. Each of the approx. 750 fig species has a highly specific fig wasp to pollinate it.
How does this work? The fig is not really a fruit, but the bulbous stem of an inflorescence, which contains a cluster of flowers. The figs emit an aroma to attract the females of a specific species of wasp, which enter the fig through a passage called the ostiole. The female wasps pollinate the small flowers inside the fig and attempt to lay eggs in some of them, too. They then die. The pollinated flowers without eggs will develop into seeds, while ovules containing eggs develop into a tissue that the wasp larvae feed on. When larvae hatch, male wasps, which lack wings and have bad eyesight, fertilize the female ones. Female wasps then exit the fig to find other figs to lay their eggs in, taking some pollen along with them, too.
When comparing fig wasps with other related wasp species, researchers have noticed that fig wasps have preserved genes for receptors that detect the aromatic compounds emitted by fig trees, a sign of coevolution of the fig and fig wasp.
Researchers have wondered why wasps do not “cheat” and lay eggs without pollinating the figs but, instead, maintain the mutualism- especially since some wasp species have to actively expend energy to collect pollen. They found, in actively pollinated pairings, if wasps do not carry pollen, trees respond by dropping the figs and killing the offspring.
Work Cited
Harrison, Rhett, et al. “Fig and Fig Wasp Biology: A Perspective from the East.” SYMBIOSIS, vol. 45, 2008, pp. 1–8, dalspace.library.dal.ca/bitstream/handle/10222/78311/VOLUME%2045-NUMBERS%201-3-2008-PAGE%201.pdf?sequence=1. Accessed 5 Nov. 2023.
J.T. Wiebes. “Fig Wasps (Hymenoptera).” Monographiae Biologicae, vol. 42, 1 Jan. 1982, pp. 735–755, https://doi.org/10.1007/978-94-009-8632-9_37. Accessed 5 Nov. 2023.
Langley, Liz. “Why Figs Need Wasps—Here’s How Mutualism Works.” National Geographic, 2020, www.nationalgeographic.com/animals/article/mutualism#:~:text=This%20is%20obligate%20mutualism. Accessed 5 Nov. 2023.
Moisset, Beatriz. “Fig Wasps.” Www.fs.usda.gov, www.fs.usda.gov/wildflowers/pollinators/pollinator-of-the-month/fig_wasp.shtml.
Ramanujan, Krishna. “Trees Strike Back When Wasps’ Efforts Are Fruitless, Biologist Finds.” Ezramagazine.cornell.edu, 2010, ezramagazine.cornell.edu/SPRING10/ResearchSpotlight.html.
Yates, Diana. “Genomic Study Reveals Evolutionary Secrets of Banyan Tree.” News.illinois.edu, 2020, news.illinois.edu/view/6367/1023624754. Accessed 5 Nov. 2023.
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