A recent study has uncovered a unique predatory behavior of web-spinning spiders in China: they force male fireflies trapped in their webs to glow like females, thereby attracting more male fireflies into their nets.
Unique predatory behavior of web-spinning spiders in China. (Photo: nytimes.com)
The study, published in the journal Current Biology on August 19, marks the first time scientists have observed such a “manipulative” behavior in spiders. The research team, led by biologists Fang Tianhua from Huazhong Agricultural University and Daiqin Li from the National University of Singapore, conducted the study after Fang observed a type of spider in Wuhan, China, that exclusively caught male fireflies.
The experiment was carried out in Hubei Province, China, focusing on the species Araneus ventricosus and the firefly Abscondita terminalis. Researchers analyzed 161 spider webs in natural settings under various conditions. Results showed that webs with glowing male fireflies and the presence of spiders caught up to 7 male fireflies, while webs without spiders caught a maximum of only 2.
Notably, the spiders exhibited different behaviors depending on the glowing ability of the fireflies. When the fireflies were still glowing, the spiders only wrapped them in silk and bit them to keep them alive, allowing them to continue glowing. However, if the fireflies did not glow, the spiders would eat them immediately.
Analysis of the light patterns revealed that the trapped male fireflies only used one of their two “lights” on their bodies to mimic the glow of females. Researchers hypothesized that the spider’s venom might inhibit oxygen supply to the fireflies’ light-producing organs or affect the function of neurotransmitters, leading to changes in their glowing behavior.
“This is a truly fascinating study,” commented Sara Lewis, an honorary professor of biology at Tufts University, who was not involved in the research. She noted that male fireflies sometimes alter their glow patterns to stand out from other males, but this new study is the first to document a glow pattern change potentially induced by a predator.
In the animal kingdom, some predators can manipulate their environment or alter their own behavior to lure more prey. However, according to Lewis, the phenomenon of a predator changing the behavior of its prey to attract additional prey is rare. The closest example is some parasitic species that can change the behavior of their hosts, such as the “zombie-ant fungus” (Ophiocordyceps unilateralis). This fungus infects ants and forces them to climb vegetation, aiding the fungus’s growth.
This research opens new avenues for understanding the complex predatory behaviors of spiders. However, experts believe further studies are needed to determine the causal relationship between spider venom and changes in the glowing patterns of fireflies.
