Milkweed Bug Life Cycle

Milkweed bugs are insects that feed on the milkweed plants and are found only where milkweed plants grow, hence, the name 'milkweed bugs'. With oblong, orange-red and black bodies, these bugs are found sucking nutrients from the seeds of the milkweed plants. Milkweed bugs have two soft inner wings, which are used to fly. The outer wings present protect the inner wings. Like other insects they have 6 legs, 3 body parts (head, thorax and abdomen) and 2 antennae. However, milkweed bugs, unlike beetles, moths, flies, and butterflies, belong to the true bugs category of insects. This means that milkweed bugs do not possess mouths for biting and chewing food, but feature a tube-like mouth part (proboscis) for sucking fluids.

There are two types of milkweed bugs, large milkweed bug (10-16 millimeters) and small milkweed bug (10-13 millimeters). Both belong to the true bug category and both feed on seeds of the milkweed plants. It is interesting to learn about the small and large milkweed bug's life cycle.

Life Cycle of a Milkweed Bug

Milkweed bugs undergo a simple metamorphosis process, involving an egg, nymph and adult stage in the life cycle process of the milkweed bug. Like the Ladybug, they also do not undergo complete metamorphosis while transforming from an egg to an adult. Let us have a look at the different stages in the life cycle of a milkweed bug.

Egg Stage
Female milkweed bugs lay eggs in small crevices present between pods on the milkweed plant. About 20 eggs a day are laid by the female a day in clusters called 'clutches'. The female lays her eggs in a ball of milkweed seed fluff or under some bark for protection. The female bug can lay about 2000 eggs in her lifetime, which is approximately one month.

Nymph Stage
The eggs hatch after a week at a room temperature comfortable for humans. As soon as eggs hatch, the milkweed bugs are in the nymph stage and appear more like miniature versions of the adult bug. The tiny tots appear like nothing but specks of dust, however, do not be fooled by their size. Their tiny microscopic bodies possess six microscopic legs, 3 tiny body parts and 2 antennae. However, at this stage some adult parts are lacking. Half of the bugs hatching out will be males, while the other half will be females.

A tough exoskeleton is also present protecting the body. This exoskeleton is not flexible and does not allow the nymph to grow further, which is why the milkweed nymph bursts open its exoskeleton and slides out. A new exoskeleton is developed, which is moist and flexible, enabling the nymph to grow to twice its size in just minutes. The new exoskeleton hardens in a few hours and the larger nymph goes about feeding itself and growing.

After a week since the nymphs have hatched, the crispy little transparent exoskeletons are again shed. This process of shedding the exoskeleton, to grow is called molting. Following the molt, the bug appears creamy yellow with bright red antennae and legs. In another few hours the body turns dark orange in color and the legs and antennae turn black again. This process of molting is carried out five times by the milkweed nymph until it becomes a fully mature adult.

Each of these nymphal stages are known as instars. The first instar corresponds to a newly hatched milkweed baby bug, while the fifth instar corresponds to the stage just before adulthood. With each instar stage, the body shape gets transformed. Formation of dark body markings and wings are seen.

Adult Stage
This gradual maturing of the insect is termed incomplete metamorphosis, wherein the bug gets larger and larger until the last molt reveals the adult bug. The entire process of metamorphosis, right from egg to adult takes 4-8 weeks, depending on the temperature of the habitat.

The adult bugs have the tips of their abdomen as black, with a bright orange segment before the tip and tiny black dots on the edges. If the segments following the orange segment has black bands, it is a male. Males are smaller in size as compared to the females. Moreover, females have markings on their ventral side, which helps distinguish males from females.

After a week or more since the bugs have reached adulthood, the bugs mate. During mating, the female and male bug will remain attached end-to-end for a long time. The female begins to lay yellow eggs in clusters of 20, a few days after mating. The adult milkweed bugs may live another 2 months after mating and laying eggs, in a sort of retirement period.

Milkweed bugs stop reproducing in the fall, as the weather gets cold and milkweed plants die. Adult milkweed bugs who have not reproduced enter a stage of hibernation during such weather and use the natural antifreeze in the body to survive the cold months. However, a large number of bugs do not make it through the rough winter months. The milkweed bug's life cycle is truly fascinating!