Insects like locusts and cicadas are often confused due to their periodic mass appearances and noisy presence. Despite these superficial similarities, they are two very different types of insects with unique biological characteristics and behaviors. This article clarifies the fundamental distinctions between locusts and cicadas.
Understanding Locusts
Locusts are short-horned grasshoppers, classified within the order Orthoptera. Their bodies are elongated, with robust hind legs designed for jumping. They possess two pairs of wings; the forewings are narrow and hardened, protecting the broader, membranous hindwings used for flight.
A defining feature of locusts is their life cycle, which includes both a solitary and a gregarious (swarming) phase. Environmental conditions, such as prolonged dry periods followed by heavy rainfall, can trigger a shift to the gregarious phase, altering their behavior. During this phase, locusts form dense, mobile bands of nymphs and swarms of adults.
Their life cycle from egg to adult often takes three to five months. Locusts primarily feed on vegetation, consuming leaves and tender plant tissues using chewing mouthparts. Their ability to form massive swarms makes them significant agricultural pests, capable of devouring vast amounts of crops.
Understanding Cicadas
Cicadas belong to the order Hemiptera, known as true bugs. They are recognizable by their sturdy bodies, widely set eyes, and short antennae. Adult cicadas have large, transparent wings typically held in a roof-like fashion over their abdomen when at rest.
Male cicadas are renowned for their loud, distinctive songs, produced by specialized organs called tymbals. These drum-like membranes, located on the sides of the abdomen, rapidly buckle inward due to muscle contractions, generating sound waves. The cicada’s hollow abdomen often acts as a resonance chamber, amplifying these sounds.
Cicadas have a unique life cycle characterized by a remarkably long nymphal stage spent underground, feeding on tree root sap. This subterranean period can last for years, with some periodical cicada species emerging only every 13 or 17 years. Annual cicadas typically spend two to five years underground. Adult cicadas feed on tree sap using piercing-sucking mouthparts, which they insert into young twigs and woody shrubs.
Core Differences
Locusts and cicadas diverge significantly in their biological classification and physical characteristics. Locusts are part of the Orthoptera order, sharing traits with grasshoppers, including large hind legs adapted for jumping and hardened forewings. Cicadas, conversely, belong to the Hemiptera order, making them true bugs with robust bodies and transparent wings. Their antennae also differ, with locusts having shorter antennae and cicadas having short, conical antennae.
Their methods of sound production also set them apart. Male locusts produce sound through stridulation, which involves rubbing their legs against their wings or rubbing parts of their wings together. Cicadas, in contrast, generate their loud calls using specialized tymbal organs, which are rapidly vibrating membranes on their abdomen. This difference in mechanism results in distinct types of sounds.
Diet and feeding mechanisms further distinguish these insects. Locusts possess chewing mouthparts, enabling them to consume large quantities of plant foliage and stems. Their diet makes them highly destructive agricultural pests. Cicadas, in contrast, have piercing-sucking mouthparts, which allow them to extract sap from plants. Adult cicadas do not consume solid plant material and cause little damage to mature plants from feeding, though females can damage young trees when laying eggs.
The life cycles and behaviors of locusts and cicadas are markedly different. Locusts have a relatively short life cycle, typically completing development in a few months. They are well-known for their swarming behavior, involving mass migrations. Cicadas, conversely, spend the vast majority of their lives as nymphs underground, some for over a decade, before emerging as adults for a brief period focused on reproduction. Their emergences, while often synchronized and numerous, are generally stationary and do not involve the destructive, migratory swarms seen in locusts.
Ecologically, their impacts also vary. Locusts can devastate crops and vegetation, posing significant threats to agriculture and food security due to their voracious appetites and swarming nature. Cicadas, while noisy and numerous during emergence, are generally considered beneficial or neutral to ecosystems. Their burrowing nymphs aerate the soil, and their decaying bodies contribute nutrients, supporting plant health and providing a temporary food source for predators.