This minuscule bug lives dangerously, possibly spending its whole life cycle on a spider’s web.
The insect species – which is new to science – is a variety of web-loving true bug. These tiny, carnivorous insects nimbly crawl along silk threads, largely ignored by their comparatively immense arachnid hosts.
Since the 2020s, at China Agricultural University in Beijing and his colleagues have been studying web-loving bugs in China.
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“They are rare, they occur in low numbers and their behaviour is quite unusual,” says Xiong. Web-loving bugs are scattered across most tropical regions but nearly 80 per cent of the species are each known from only a single location, he says.
During fieldwork in Fujian province in September 2025, Xiong found tiny, millimetre-long insects – barely bigger than grains of table salt – living in the tangled homes of funnel web spiders. He collected them and brought them into the lab for identification and further study.
After comparing the physical features of the tiny reddish bugs to the few known web-loving bug species, Xiong and his team determined they belonged to an undescribed species, which they named Heissophila sinica. The bugs are smaller than their closest relatives, which live predominantly in South-East Asia.
Web-loving bugs capitalise on an ephemeral microhabitat made by spiders and a few other silk-weaving arthropods. In H. sinica, the size difference between the spider and the bugs may keep them from being targeted as food.
“They do not avoid the [spider] at all,” says Xiong. “On the contrary, they like to follow it about and circle around it, for reasons we do not yet understand.”
The bugs feed on the scraps left after the spider eats, and they also eat up web-dwelling mites – some of which are spider parasites.
“When the spider moults, [the bugs] gather round and drink the spider’s body fluids,” Xiong says. He and his colleagues aren’t yet sure whether the bugs mostly help or hinder the spiders. Another option is that they have largely do neither, which would make the bugs commensal organisms.
The insects may live their entire lives on the spider’s web. The team has found eggs, juveniles and adults on the web simultaneously. It’s still unclear precisely how the bugs manage to climb around on the silk without becoming stuck, but Xiong says it may come down to the insects’ unusual feet, which have just two simple claws and lack many of the other structures found in other insects’ feet.
at the American Museum of Natural History in New York lauds the research team for the fieldwork efforts and for documenting the natural history of such bizarre and diminutive insects.
“None of this [work] is straightforward, including finding the spiders and their burrows or observing these tiny bugs under what are oftentimes less than ideal conditions,” he says.
Xiong and his colleagues plan to increase their efforts collecting web-loving bugs in China and neighbouring regions to gather genetic data to help them better understand the evolution of these mysterious spider web tenants.
ZooKeys
