To answer the question posed in the title – no, baby spiders do not drink milk. Spiders are not mammals, so they do not produce milk or breastfeed their young. Instead, baby spiders are born ready to hunt and feed themselves.
How do baby spiders eat when they first hatch?
When spider eggs hatch, hundreds or even thousands of tiny spiderlings emerge. These freshly hatched spiders are extremely small, sometimes less than a millimeter long. They are also fragile and vulnerable. But despite their tiny size, spiderlings are essentially miniature versions of adult spiders, with functioning mouths, legs, silk glands, and simple eyes.
Spiderlings do not need to drink milk from their mother. They have the instinct and ability to hunt and feed themselves immediately after hatching. Here are some ways that newly hatched spiderlings find food:
- Eat eggshells – Some spiders may nibble on the eggshell fragments left behind in the egg sac after hatching.
- Eat siblings – Spiderlings of some species will turn cannibalistic, eating unhatched eggs or their own brothers and sisters. This provides nutrition and reduces competition.
- Scavenge pre-killed prey – Mother spiders may provide dead or paralyzed insects in the nest web for the babies to feed on.
- ballooning – This is when tiny spiders spin silk strands and launch themselves into the air to disperse and find new food sources.
- Actively hunt small prey – Despite their extremely small size, spiderlings can take down tiny insects, mites, springtails, and other arthropods soon after hatching.
Even if the mother spider dies before the eggs hatch, the spiderlings have the innate hunting skills and instinct to fend for themselves once they emerge. They do not need parental care.
How do spider mothers care for their young?
Although they do not directly nourish their babies, most spider mothers do provide some degree of care and protection:
- Spin egg sac – Female spiders spin silken egg sacs, often infused with protective chemicals. This creates a safe place for the eggs to incubate until hatching.
- Stand guard – Some female spiders will stand guard over the egg sac, protecting it from predators and parasites.
- Let spiderlings ride – After hatching, young spiders may cling to their mother’s abdomen or back for safety during the early dispersal phase.
- Share web – Spiderlings may live in their mother’s web for a few days after hatching, which provides food sources and safety while they grow stronger.
- No care – Many spiders provide no care at all, abandoning the egg sac right after it is spun and laid.
But in all cases, the mother spider does not actively feed her babies after they emerge. Nurturing her young with milk or regurgitated food goes against the innate solitary and predatory nature of spiders.
Do any arthropods feed their young milk?
Milk is defined as a nutrient-rich secretion from mammary glands that female mammals produce to nourish their offspring. No arthropods, including insects and spiders, possess mammary glands or produce anything that could be defined as milk.
However, some insects and arthropods have evolved ways to nourish their young that bear similarities to milk:
- Pigeon milk – Both male and female pigeons produce a curd-like substance in their crop organ to feed newly hatched squabs. It contains protein, fat, and immune components.
- Cockroach milk – Female cockroaches provision their young with protein crystals secreted from brood sacs. The crystals contain essential amino acids.
- Lacewing milk – Lacewings are insects that secrete a milk-like substance from specialized glands in their reproductive tract to nourish eggs and larvae.
Despite being called ‘milk’, none of these secretions contain the defining mammalian milk proteins, lactose, or casein. They are convergently evolved mimics that serve a similar purpose of nourishing developing young.
Do any spiders exhibit parental care?
While maternal care and feeding of young are rare in spiders, there are a few exceptions where more complex parental care has evolved:
- Wolf spiders – Female wolf spiders allow their spiderlings to ride on their backs for safety. The mother may also share killed prey.
- Jumping spiders – Some jumping spiders regurgitate food to directly feed their spiderlings.
- Lynx spiders – Females guard the egg sac until hatching, then allow the spiderlings to ride on their backs.
- Recluse spiders – Recluse spiders stand guard over the egg sac after it is spun and may share food.
However, direct milk provisioning does not occur in any known spider species. The solitary predatory lifestyle of most spiders likely precludes the evolution of complex food sharing between generations.
Do male spiders provide care for their young?
In most spider species, male spiders do not provide any parental care. Their only role is to mate with the female.
However, in a handful of species, male spider behaviors have been observed that support their offspring:
- Let spiderlings cannibalize them – Male dark fishing spiders allow newly hatched babies to eat parts of their body as a nutrient boost after hatching.
- Share caught prey – Male nursery web spiders capture insects and allow the babies to feed.
- Guard egg sac – Male wolf spiders stand guard over the egg sac until hatching.
- Regurgitate food – Some male caerostris darwini spiders vomit to feed their young.
Even in the rare cases where male spiders do provide care, they do not possess milk or feed babies in the manner that mammalian mothers do. Spider behavior centers around laying eggs and letting offspring fend for themselves.
Conclusion
In summary, baby spiders are independent hunters from the moment they emerge from their eggs. They do not need to drink milk or any other substance provided by a parent to survive. While a few arachnid behaviors mimic mammalian maternal care in limited ways, no spiders actually produce milk or breastfeed. The solitary, predatory nature of spiders means that spiderlings must quickly learn to capture prey on their own in order to eat and grow.