This wasp turns spiders into zombie builders (then eats them)
Scheming wasps that ride spiders like horses, turn them into zombies, and then program them to weave stronger webs than normal sounds like science fiction. Unfortunately for the Cyclosa argenteoalba spider, though, it's ghoulish fact, and researchers have discovered that the ichneumon wasps that enslave them are even more controlling than previously thought.
The wasps' parasitic behavior was already known to be devilishly refined. Each wasp larvae clings to a spider, drugging it and then getting it to spin a web on which the controlling insect can develop to maturity.
There's no promise of old age for the spider, however, or even a well-deserved rest after all its construction work.
Once it has completed the web, it's directed to the center by the wasp, where its body is sucked dry by the larvae for nutrients.
What's interesting, though, is how the web the spider weaves differs from its normal, non-zombie web. Japanese scientist Keizo Takasuka and his team discovered that the wasp manipulates its spider steed into producing silk that is 2.7-40x stronger than typical, while the designs are more reflective and include extra reinforcement.
In fact, Takasuka's research – published in The Journal of Experimental Biology – found, the webs the zombie spiders create are more akin to their own "resting web" designs. Such examples are less commonly produced, only when the spider itself wants to shed its skin in safety.
What's still unclear is how the wasp actually directs its worker to switch from regular web design to super-strength. One possibility is a dose of artificially-produced hormone that fools the spider into thinking it's time to shed.