What is the Difference between a Cicada and a Locust

Cicadas vs. Locusts: Understanding the Differences

Cicadas and locusts are often confused, but they are distinct insects with different classifications, appearances, lifecycles, and behaviors. Understanding these differences helps explain why they look alike to the casual observer but act very differently in nature. Recognizing these distinctions is important for both ecological studies and agricultural practices.

Taxonomy and Classification

• Cicadas are true bugs in the order Hemiptera, family Cicadidae, and are most famous for their loud mating calls produced by structures on the abdomen called tymbals. Locusts are a form of grasshopper within the order Orthoptera, typically associated with the family Acrididae and the phenomenon of swarming. In short, cicadas are true bugs, while locusts are a type of grasshopper.^[5][9]
• Both groups play unique roles in their ecosystems, and understanding their classification can help in conservation efforts.

Appearance and Anatomy

• Cicadas have broad, shield-shaped bodies, large compound eyes, and clear membranous wings with visible venation. Locusts resemble other grasshoppers, with strong hind legs built for jumping, and they can vary in color but often display earth-toned patterns that help them blend with vegetation. The visual differences reflect their different evolutionary lineages and life histories.^[3][5]
• These adaptations serve critical functions; for example, the coloration of locusts can provide camouflage from predators, while cicadas' distinctive body shape helps them in sound production.

Sound Production and Communication

• Male cicadas create very loud, distinctive sounds using tymbals on their abdomen to attract females and defend territory. Locusts generate sound primarily through stridulation, rubbing legs against wings or body parts to communicate within swarms and coordinate mating in crowding conditions. The purpose of the sounds differs: cicada calls are largely about mate attraction and predator deterrence via predator satiation, while locust sounds help maintain swarm cohesion and mate locating within the group.^[1][5]
• The sounds produced by each group are crucial for their survival, serving both reproductive and social functions that are essential in their respective environments.

Life Cycles and Swarming Behavior

• Cicadas have long, species-specific life cycles, often with periodic emergences that can be 2, 13, or 17 years depending on the species and region. Locusts exhibit swarming behavior when environmental conditions trigger a dramatic shift from solitary to gregarious phases; these swarms can include billions of individuals and travel long distances, driven by food availability and weather. Cicada emergences are predictable and cyclical, whereas locust swarms are irregular and tied to ecological triggers such as drought followed by vegetation abundance.^[1][5]
• The implications of these life cycles are significant; for instance, cicadas can provide a burst of nutrients to the ecosystem upon their emergence, while locust swarms can lead to immediate agricultural crises.

Ecological Impacts

• Cicadas emerge in large numbers but usually for short bursts and leave behind exuviae (the shed skins) on trees; their primary ecological impact is soil aeration from nymphs and providing a pulse of nutrients when they die. Locust swarms can cause extensive crop and vegetation damage over large areas, potentially leading to food security concerns in affected regions. The scale of impact for locusts is generally much greater in terms of economic and agricultural effects than typical cicada emergences.^[5][1]
• This difference highlights the varying roles each insect plays in their environments; while cicadas contribute positively to soil health, locusts can pose significant threats to agricultural productivity.

Common Misconceptions

• A frequent misconception is that cicadas and locusts are the same insect. While both can produce loud sounds and appear in large numbers at times, their taxonomy, life histories, and behaviors are fundamentally different. In many regions, resources and outreach materials explicitly distinguish cicadas as Hemiptera and locusts as a form of grasshopper, clarifying the true relationship between the two.^[7][9]
• Educational efforts are crucial in dispelling these myths, as understanding the differences can lead to better management practices in both urban and agricultural settings.

Quick Reference Cheat Sheet

Illustrative Example

• In a temperate park, you might hear a cicada chorus on a warm afternoon, a chorus produced by many males signaling mates in a cyclical, species-specific pattern. In a nearby agricultural region, a locust outbreak could involve swarms flying across fields, consuming vegetation rapidly and altering the landscape for weeks. These contrasting scenarios illustrate how the two insects occupy different ecological roles despite superficial similarities in appearance and vocalizations. Understanding these roles is essential for both ecological balance and agricultural management.