Dual-Venomed Assassin Bugs Store Their Chemical Arms Separately

A well-fed assassin bug in the lab at the University of Queensland. Photo Credit: Christie Wilcox In one of his journal entries from his time aboard The Beagle, Charles Darwin told of a "great black bug" and how it boldly sucked blood from his finger through its large mouthpart. The creature was likely Triatoma infestans, a kissing bug—one of the almost 7,000 species of assassin bug that are now described. Like its kin, it's armed with an ominous looking proboscis which it uses to slurp up its meals. But the kissing bug is one of only a few assassin bugs with vampiric tastes. Most are much more murderous, preferring to use potent venoms to paralyze a their prey so they can liquify them from the inside out, then suck their soupified meal through their needle-like mouths. It was that behavior which intrigued Andrew Walker, a molecular entomologist and postdoctoral fellow in the Institute for Molecular Bioscience at The University of Queensland. He and his colleagues were curious what the paralyze then liquify-and-slurp venom looked like. "We wanted to see if assassin bugs had venom that was similar in composition to other venomous animals due to convergent evolution, or if the different feeding physiology would result in a different composition," he said. And when their research began, essentially no one has looked at their venoms—"almost nothing was known about them." But what they found was much more surprising: the animals are equipped with two different venoms, which are made and stored in distinct compartments—a first for any venomous animal.