Grasshoppers are jumping insects known for their powerful hind legs and herbivorous diet. Unlike mammals or birds, a grasshopper is not born live but begins its life cycle inside an egg, emerging through incomplete metamorphosis. This developmental path involves three main stages: the egg, the nymph, and the adult, bypassing the larval and pupal stages seen in many other insects.
Reproduction and Egg Deposition
The cycle begins with mating, typically during the late summer and early autumn. Following fertilization, the female uses a specialized structure at the end of her abdomen, called an ovipositor, to bore a hole into the soil. She often chooses firm, undisturbed ground or sand, extending her abdomen deep into the ground to create a secure chamber.
As she lays her eggs, they are bundled together into a structure called an egg pod. This pod is created by encasing the eggs in a protective, frothy, sticky substance that hardens upon exposure to the soil.
This hardened, waterproof secretion provides insulation and camouflage, protecting the embryos from predators and harsh weather, especially through the winter. A single egg pod can contain 10 to 300 rice-shaped eggs, depending on the species. Many females lay multiple pods throughout the season before the cold weather ends their life cycle.
The Incubation Period and Hatching
The period spent within the egg is the longest stage, often lasting through the entire winter season. In temperate climates, embryos typically enter diapause, a state of suspended development, shortly after the eggs are laid in the fall. This mechanism halts growth, preventing hatching when food is scarce and temperatures are low.
Diapause is broken by prolonged exposure to low ground temperatures during the winter. Development resumes in the spring once the soil temperature warms sufficiently, often reaching 50 to 55 degrees Fahrenheit. This timing ensures the nymphs hatch when tender, young plant foliage is readily available for feeding.
The embryo undergoes several developmental stages inside the egg, sometimes including a 180-degree rotation of its body axis. When emergence arrives, the young grasshopper is called a pronymph, possessing a temporary, membranous casing. The pronymph forces its way out of the egg and up through the soil plug of the egg pod, often using a temporary head-pulsing organ. Upon reaching the surface, the pronymph immediately sheds its outer membrane in a mini-molt, emerging as a first-stage nymph.
Growth and Development (The Nymph Stage)
Once hatched, the nymph closely resembles a miniature adult, though it lacks fully developed wings and reproductive organs. Nymphs immediately begin feeding on soft vegetation and must grow rapidly by repeatedly shedding their rigid outer skeleton, a process known as molting.
Each stage between molts is called an instar; a grasshopper typically progresses through five to six instars before reaching its final adult form. During the nymphal stage, which lasts between 40 and 60 days, the developing insect’s wings appear as small, external wing pads. With each successive molt, these wing pads become larger and more defined.
The nymphal period is characterized by intense feeding and growth. The duration of each instar depends on environmental factors like temperature and food availability. The final molt, known as the imaginal molt, transforms the nymph into a sexually mature adult with fully functional wings, completing its incomplete metamorphosis.