An international research team in Morocco has discovered a potentially new blow fly species thriving within a termite colony. These larvae have evolved astonishing adaptations to infiltrate the colony, including a rear end shaped like a termite’s head, antennae-like tentacles, and the ability to mimic the colony’s scent. This remarkable camouflage allows the larvae to evade detection by soldier termites, who typically eliminate intruders, and even receive care from the colony’s workers.
This discovery was a serendipitous one, as biologist Roger Vila from the Institute of Evolutionary Biology explained in a Spanish National Research Council statement. The team, primarily focused on butterflies and ants, stumbled upon the larvae while searching for ants during a period of heavy rain. Three larvae were found within a termite mound, unlike any they had ever seen. Subsequent expeditions to the same area yielded only two more larvae, highlighting the rarity of this species.
A study published in Current Biology details the larvae’s “termite mask”—a rear appendage shaped like a termite head, complete with non-functional antennae and palps that perfectly mimic the size of those found on large harvester termites. The larvae’s breathing holes, or spiracles, further enhance the disguise by resembling eyes on the termite mask. This adaptation is particularly clever given that harvester termites, unlike other termite species, have functional eyes due to their foraging activities at dusk.
Termites rely on scent and touch for identification, using their antennae to communicate within the colony. The fly larvae have evolved antenna-like tentacles along their bodies, likely facilitating interaction with multiple termites simultaneously. Furthermore, chemical analysis revealed that the larvae’s scent is indistinguishable from that of the termites in the colony they inhabit, providing a crucial chemical disguise that allows them to integrate seamlessly into the termite society.
Observations in a laboratory setting revealed that the larvae often positioned themselves in the busiest areas of the termite nest, where they were groomed and possibly even fed by the unwitting termites. However, the larvae’s diet remains unknown, and their adult form remains a mystery, as the observed larvae died before metamorphosis. The researchers speculate that crucial elements of the symbiotic relationship between the termites and the flies may have been lost in the laboratory transfer.
While humpback flies also exhibit masking behaviors to mimic termites, they do so in their adult stage, unlike these newly discovered larvae. The evolutionary divergence between blow flies and humpback flies predates the split between humans and mice by millions of years. This vast timeframe reinforces the researchers’ confidence in their discovery of a new case of social integration evolution.
The new fly belongs to the genus Rhyncomya. Given the absence of similar behavior in other known Rhyncomya flies, the researchers believe this species’ unique lifestyle likely evolved rapidly. This groundbreaking discovery marks the first documented observation of a blow fly larva successfully living in disguise among termites, a testament to the power of natural selection and adaptation.
