As anyone who’s lived in a terrible student apartment can attest, cockroaches are just as interested in your food as you are, if not more so. Turns out, Keith Richards’ post-apocalyptic army has a particularly strong sweet tooth—strong enough to defeat the brains and brawn of the human-run pest control industry!
This happened through a unique and circuitous route. Male German cockroaches secrete a sticky, maltose-filled residue on their abdomens to attract interested mates. When a female consumes the goo, it converts to delicious glucose in contact with her saliva, all while she gets in the perfect position for the male to mate with her—next generation achieved. The pest-control industry took advantage of this fact since the 1980s, creating a whole raft of glucose-based poison bait traps to lure hungry (and lustful) roaches to their doom. As a result, research later showed, a strain of cockroaches started tasting glucose as repellently bitter, turning them off the traps—and the males offering the standard mating goo. But all was not lost for all those cockroach babies yearning to be born. Enter evolution.
“Males that also avoid glucose possess genetic mutations that allow them to make gooey gifts composed mostly of a more complex sugar called maltotriose, which the female’s saliva cannot as readily break down into glucose. With no glucose to turn them off, the females stick around for the males to do their thing. Moreover, these males get into a mating position much more quickly than those that offer typical glucose gifts, the researchers found. Together, these adaptations help glucose-averse cockroaches successfully mate, which should make roaches that avoid sugary bait more and more common.”
This turn of events is documented in the most recent Proceedings of the Royal Society B. And while it’s excellent news for Blatella germanica, it’s terrible for us: pest control needs to pivot from the sure bet of sugar traps soon, or our kitchens will be overrun by roaches not just immune to their charms, but outright disgusted by them. I do try to hold a healthy respect for those canny survivors. And I am in awe of the chutzpah it takes to evolve aversion to glucose—a nearly ubiquitous fuel for life forms on earth. But as someone who has a kitchen at home and at work, I hope any and all cockroaches enjoy their maltotriose-eating and baby-having as far away from me as possible!