Millipedes, fascinating arthropods with segmented bodies and many legs, are often encountered in gardens and moist environments. They play a significant role in ecosystems as decomposers, breaking down decaying organic matter. While adult millipedes are easily recognizable, their young undergo a remarkable transformation, appearing quite different from their mature counterparts.
Appearance of Young Millipedes
Newly hatched millipedes, known as hatchlings or first instars, are small and delicate. They measure a few millimeters in length, making them difficult to spot without close inspection. Their coloration is often pale, translucent or whitish, which contrasts with the darker, more defined hues of adult millipedes.
A distinctive feature of these young millipedes is their limited number of legs and body segments. When they first emerge from their eggs, they possess only three pairs of legs, followed by up to four legless segments. This gives them a somewhat “worm-like” appearance, as their body seems disproportionately long compared to their initial leg count. Their body shape is generally cylindrical and rounded, similar to that of adult millipedes.
Growth and Molting Stages
Millipedes grow through a process called molting, where they shed their rigid outer exoskeleton. This shedding allows them to increase in size and develop further. During this vulnerable period, young millipedes burrow into the soil or substrate for protection, and they sometimes consume their discarded exoskeleton to regain nutrients.
With each successive molt, the appearance of a young millipede changes noticeably. They gradually increase in overall length and girth. New body segments and additional pairs of legs are added with every molt, a developmental process known as anamorphosis. As they progress through these numerous instar stages, their coloration also begins to deepen and solidify, eventually acquiring the characteristic pigmentation of their species. This continuous transformation, often taking several months to years, leads to full adulthood.
Identifying Young Millipedes
Distinguishing young millipedes from other small invertebrates requires observing a few key characteristics. A primary identifier is the arrangement of their legs: millipedes, even in their early stages, have two pairs of short legs per body segment, positioned directly underneath their rounded bodies. This contrasts with centipedes, which have only one pair of legs per segment, extending from the sides of their flatter bodies.
Another differentiating factor is their movement. Young millipedes move slowly and deliberately, exhibiting a wave-like motion of their many legs. Centipedes, conversely, are faster and more agile. If disturbed, a young millipede curls into a tight coil, protecting its softer underside, while a centipede scurries away quickly. Furthermore, millipedes, including their young, primarily feed on decaying plant matter, unlike carnivorous centipedes. These combined traits allow for accurate identification of young millipedes in their natural habitats.