Thai Plant Mimics Figs to Deceive Wasps and Reward Flies for Pollination

A rare plant species discovered in Thailand uses a sophisticated dual strategy, mimicking fig fruit to deceive pollinating wasps while offering a legitimate breeding reward to flies, according to a study published in the journal New Phytologist.

The plant, Heterostemma ficoides, belongs to the Apocynaceae family and produces flowers that strikingly resemble closed fig inflorescences, known as syconiums. While figs engage in a well-documented mutualistic relationship with fig wasps, where insects provide pollination in exchange for a safe breeding site, the researchers investigated whether this plant acts as a deceptive mimic.

Chemical Deception and Wasp Attraction

Over five years of field observations, scientists analyzed the volatile chemical compounds released by the flowers. The scent profile contained 22 volatile compounds closely matching those of real figs, successfully tricking Kradibia fig wasps into entering the blossoms. However, unlike real figs, the deceptive flowers do not offer ovaries for the wasps to lay eggs, leaving the duped insects without a reproductive payoff.

Despite the deception, the wasps occasionally contribute to pollination. Researchers found dead wasps carrying pollen loads inside the flowers, designating them as secondary pollinators that visit the plants when true figs are unavailable.

Mutualism with Flies

While wasps experience deception, flies from the Megaselia genus benefit from a true mutualistic partnership. These flies mate on the flower surfaces, lay their eggs inside, and successfully rear their larvae. Frequent visits by the flies, coupled with pollen grains found on their mouthparts, identify them as the plant's primary pollinators.

Lead researcher Arunrat Kijio noted that the findings demonstrate how a single flower can integrate two contrasting pollination strategies—deception and mutualism—to exploit different insects for reproductive success.