Stink bugs, recognized by their distinctive shield-shaped bodies and the unpleasant odor they release when disturbed, are common insects found in gardens and occasionally indoors. The brown marmorated stink bug, an invasive species, has become particularly prevalent in North America, feeding on various fruits, vegetables, and ornamental plants. Understanding their life cycle, especially their egg-laying habits, is helpful for managing their populations.
When Stink Bugs Lay Their Eggs
Stink bugs typically begin their egg-laying activities in the warmer months of late spring and early summer. This period, generally from May through August, aligns with rising temperatures and abundant plant growth. Adult stink bugs emerge from their overwintering sites in early spring, seeking mates to initiate this reproductive phase. A single female stink bug can lay up to 500 eggs in her lifetime, often producing several batches. In warmer climates, multiple generations of stink bugs can occur within a single year, sometimes up to three or four, due to the rapid life cycle and extended warm periods.
Where Stink Bugs Lay Their Eggs and What They Look Like
Female stink bugs carefully select locations for their eggs, primarily choosing the undersides of leaves or plant stems. This strategic placement helps protect the eggs from predators and harsh environmental conditions. They are not particularly selective about the plant species, laying eggs on a wide variety of fruits, vegetables, and ornamental plants, including apple and peach trees, beans, corn, and tomatoes. While less common, they may also lay eggs indoors in sheltered spots if they infiltrate homes.
Stink bug eggs are small, typically about 1 millimeter across, and have a distinctive barrel shape. Their color can vary, appearing light green, pale yellow, or white when first laid. As they develop and approach hatching, the eggs may darken slightly, sometimes turning gray or black. The eggs are usually laid in neat, symmetrical clusters or rows, with each cluster containing between 20 to 30 eggs.
The Stink Bug Egg Hatching Process
The eggs undergo an incubation period. This period is relatively short, typically lasting about 4 to 7 days, though it can vary based on temperature and humidity. Warmer conditions generally accelerate the hatching process. When ready, the eggs hatch into young stink bugs known as nymphs.
Newly hatched nymphs are small, wingless, and often differ in appearance from adult stink bugs. For instance, the first-stage brown marmorated stink bug nymphs are typically orange or red in color and remain clustered around their empty egg shells. As they grow, nymphs progress through five developmental stages, called instars, shedding their skin with each stage. They increase in size and change in coloration during these stages, gradually beginning to resemble the adult form, though they will not develop wings until their final molt into adulthood.