Spiderlings, or hatchlings, represent a distinct life stage with feeding habits significantly different from those of adult spiders. Their minuscule size dictates unique challenges in acquiring nutrition, requiring specialized initial food sources and hunting strategies scaled to their environment. The journey from a newly hatched arachnid to a self-sufficient hunter involves a rapid shift in diet and behavior, moving from passive internal reserves to active, highly specific predation.
The First Meal: Initial Nutritional Sources
For many species, a spiderling’s first source of nutrition is an internal, passive one, sustaining them through the first few days of life before they disperse. Upon hatching, the spiderling absorbs the residual yolk material remaining from the egg stage, providing a nutrient-rich foundation for early development. This internalized reserve allows them to complete their first molt, often while still inside the protective egg sac, without needing to immediately search for external food.
Some spider species exhibit more complex maternal provisioning strategies to support this early stage. The mother may lay non-viable eggs, known as trophic eggs, which the spiderlings consume to gain extra protein and fat. This practice can greatly increase a hatchling’s chances of survival once it ventures out. In extreme cases, such as with the African social spider, the mother offers herself entirely, a process called matriphagy, ensuring her offspring receive a massive nutritional boost.
Active Hunting and Prey Selection
Once spiderlings disperse from the egg sac, their diet shifts entirely to external sources, focusing on prey that matches their exceedingly small size. Newly independent hatchlings are limited to feeding on microscopic arthropods and other invertebrates, as they lack the strength and venom capacity to subdue larger insects. Their prey must be manageable, often consisting of organisms smaller than a millimeter.
Common prey includes springtails (Collembola), which are abundant in leaf litter and soil, as well as various species of mites and aphids. A spiderling’s success depends heavily on the ratio of its own body size to that of its potential meal. As spiderlings molt and grow larger, their prey base expands from tiny mites to small fly larvae or fruit flies (Drosophila), allowing them to tackle progressively larger insects.
Hunting methods among spiderlings vary significantly, reflecting the diverse strategies of their species. Spiderlings of web-building species, such as orb weavers, construct miniature versions of their adult webs, which act as passive traps for minute flying or crawling prey. Conversely, the young of hunting spiders, such as jumping spiders and wolf spiders, actively stalk and pounce on their prey, relying on superior eyesight and speed to secure a meal.
How Spiderlings Consume Their Food
Regardless of whether a spiderling is a passive trapper or an active hunter, consuming prey involves a specialized biological event known as external digestion. Spiders have a narrow gut that prevents them from ingesting solid food, necessitating the liquefaction of their prey before consumption. This process begins when the spiderling uses its chelicerae, or fangs, to inject both venom and a cocktail of digestive enzymes into the captured arthropod.
The enzymes break down the prey’s internal tissues, turning the contents into a nutrient-rich liquid within the insect’s exoskeleton. In many cases, the spiderling uses its chelicerae to crush or shred the prey, creating a pulpy mass while continually flooding it with digestive fluid. Some spiders may even pump the digestive fluid back and forth to ensure maximum breakdown.
Once the prey’s insides are fully liquefied, the spiderling uses a muscular organ called the sucking stomach to draw the resulting liquid “soup” into its foregut. Specialized filters within the mouth cavity ensure that only liquid is ingested, leaving behind the hollow, indigestible exoskeleton. This method allows the tiny spiderling to efficiently extract all necessary nutrients from a meal.