Locusts and cicadas are often confused due to their occasional large appearances and general insect resemblance. However, they are distinctly different species with unique biological characteristics and behaviors. This article clarifies their relationship by exploring their classifications, physical attributes, life cycles, and sound production.
Understanding Locusts
Locusts are short-horned grasshoppers belonging to the family Acrididae, within the order Orthoptera. They have strong hind legs for jumping and chewing mouthparts. Typically solitary, these insects live inconspicuous lives.
Under specific environmental conditions, like drought followed by rapid vegetation growth, locusts undergo a significant behavioral and physiological transformation. This change, often triggered by increased serotonin from crowding and tactile stimulation, leads them to switch from a solitary to a gregarious phase. In this phase, they form large, destructive swarms that travel long distances and consume significant vegetation, including leaves, grasses, and agricultural crops.
Understanding Cicadas
Cicadas are insects classified within the order Hemiptera, specifically the suborder Auchenorrhyncha. They have large, often red, eyes set wide apart, clear membranous wings, and stout bodies. Unlike locusts, cicadas possess piercing-sucking mouthparts, which they use to feed on plant sap by inserting a needle-like stylet into trees and woody shrubs.
Cicadas have a unique life cycle, including a prolonged nymphal stage spent underground. Nymphs can remain buried for 2 to 17 years, feeding on fluids from plant roots. After this extensive subterranean period, they emerge as adults to molt, reproduce, and produce their characteristic loud sounds. Male cicadas create this sound using specialized structures called tymbals, ribbed membranes on their abdomen. Muscles rapidly buckle these tymbals, generating clicks that form their loud buzzing chorus.
Key Distinctions and Shared Traits
Locusts and cicadas, while both insects, are fundamentally different in their biological classification, life cycles, sound production, and feeding habits. Taxonomically, locusts belong to the order Orthoptera, which also includes grasshoppers and crickets. Cicadas, in contrast, are part of the order Hemiptera, commonly known as “true bugs,” a group that includes aphids and leafhoppers. This difference in orders signifies a deep evolutionary divergence.
Their life cycles present a major distinction. Locusts undergo incomplete metamorphosis, with nymphs resembling smaller adults, and are notable for their ability to switch between solitary and gregarious phases, leading to rapid swarming behavior. Cicadas, conversely, are known for their exceptionally long nymphal stages, spending years underground before a synchronized emergence as adults. While cicadas can emerge in large numbers, they do not exhibit the destructive, migratory swarming behavior seen in locusts.
The methods of sound production also differ. Male cicadas produce loud calls by vibrating specialized membranes called tymbals on their abdomen. Locusts, as Orthoptera, typically create sound through stridulation, which involves rubbing body parts together, such as their hind legs against their wings. Their feeding habits are also distinct: locusts have chewing mouthparts and consume plant foliage and crops, leading to significant agricultural damage during swarms. Cicadas possess piercing-sucking mouthparts and feed exclusively on plant sap, typically from tree roots as nymphs and woody plant stems as adults, causing far less damage to mature plants. Despite these differences, both are insects that can appear in large populations and are herbivores, feeding on plant matter in some form.