If you think your ungrateful kids just take and take and take, wait until you hear about the miscreant youths of the desert spider Stegodyphus lineatus. After tirelessly chucking up the contents of their guts to feed the hungry mouths of their young, Mom’s make the ultimate, second to none sacrifice in the name of motherhood: They serve themselves up as dinner for the little’uns. How disgustingly chivalrous.
Interestingly, according to a new study, it turns out that the mother’s internal anatomy begins to turn into a gloopy liquid before the greedy beggars have even hatched, all in preparation for her consumption. Because why force your kids to waste energy chewing when they can slurp you down like a smoothie, right? Alongside being repulsively interesting, the researchers report that this is the first demonstration of the mechanism underlying suicidal maternal care not just in spiders, but across all arthropods so far studied. The study has been published in The Journal of Arachnology.
Stegodyphus lineatus is a subsocial spider that can be found spinning capture webs between twigs on bushes in the Negev desert, southern Israel. Females construct loosely woven webs, according to Israel Cohen Institute for Biological Control researcher Mor Salomon, who told Science News that they somewhat resemble a ping-pong net. These webs, which are only around 30 centimeters wide, are attached to a cone-shaped silk retreat that the female decorates with debris and the carcasses of her prey.
Within this tiny cave, the female constructs a small, hockey puck-shaped structure stuffed with up to 80 eggs. If a male does not come along and perform infanticide, detaching the egg sac with his mouthparts and subsequently tossing it to the ground, then the spiderlings will hatch inside this cave. Trapped inside, the mother then pierces the silk so that they can escape and then spends the next two weeks caring for them, regurgitating up her previous dinners for them to dine on.
But it turns out the goo she vomits up is not just composed of food; the researchers discovered that her guts start to degrade whilst the egg sac is incubating, forming part of the regurgitated fluid. When the spiderlings emerge, her gut tissues are already partly liquefied, but this process intensifies as she begins to chuck up her innards to feed her young. Impressively, she regurgitates 41% of her body mass to feed her offspring.
Next, something even more disturbing happens: The baby spiders puncture her abdomen with their mouthparts, or chelicerae, and begin to gorge on her guts. The researchers even prodded females during this process and they withdrew their legs, demonstrating that they are being eaten alive. Of course, when the spiderlings are done with her, she is very much dead.
From these observations, the researchers conclude that the mother’s guts undergoes gradual degradation in order to maximize the nutritional potential of her body, ultimately allowing her offspring to completely devour her body.