Photo credit: Dr. Zhanqi Chen
Birds don’t do it, bees don’t do it, even educated fleas don’t do it. When it comes to babies drinking milk, breastfeeding probably comes to mind. If you’re Australian, or well versed in biology, you might also think of marsupials (which, although they produce milk, should you drink it?). If you really spend your time reading up on milk-producing animals, then you might even know about a few breastless members of the Milk Club, like cockroaches.
Thanks to Dr. Zhanqi Chen of the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences, you can now add spiders to your List of Things That Suckle.
On 30 November, Dr. Chen and his colleagues published their discovery of Toxeus magnus, an ant-mimicking jumping spider (pictured above) that not suckles its young in the journal Science.
Not only did the scientists observe the spiders feeding milk to their young, but in a remarkable first, the spider mothers continued to care for their young into adulthood. According to Chen and his colleagues, spiderlings remained in the nest, nursing on their mother’s milk for nearly 40 days, shortly before reaching sexual maturity.
The authors suggest that the adult offspring continue to derive health benefits from the milk, although they don’t yet know what these specific benefits are, as the spiders can thrive perfectly well without it.
The authors observed that although the mothers treated all juveniles the same, only daughters were allowed to return to the breeding nest after sexual maturity. This suggests that the mothers’ care and nursing is important in maintaining enough adult female offspring to maintain a healthy population.
This remarkable discovery shows that mammal-like milk production and parental care has evolved well beyond the usual furry suspects. Now have fun trying to forget about cockroach milk.