Are Cicadas and Locusts the Same Thing?

Cicadas and Locusts: Understanding the Differences

Cicadas and locusts are not the same insect, though they share a broad family resemblance as medium-sized hemipterans that can attract attention when numbers are high. In short: cicadas are not locusts, and locust swarms are not a universal fate for cicadas. This article untangles their differences in biology, behavior, and ecological impact.

What They Are and Where They Fit In

• Cicadas belong to the superfamily Cicadoidea within the order Hemiptera, known for their distinctive singing males and periodic or annual life cycles that take years to emerge above ground. Cicadas are recognized for their unique life cycle, which can be fascinating to study. Locusts are not a single species but a behavioral form taken by certain short-horned grasshoppers (family Acrididae) that can swarm under environmental triggers. In essence, cicadas are true bugs with a unique life cycle; locusts are grasshoppers that can become swarming contenders under the right conditions. This distinction matters for understanding their ecology and how humans manage their effects on ecosystems and agriculture.

Life Cycles and Development

• Cicadas spend the majority of their lives underground as nymphs, feeding on sap from tree roots, before emerging synchronously as adults. Their emergence often occurs in large numbers, creating a spectacular natural event. Some species have lengthy underground phases (periodical cicadas), while others emerge annually, but all share a metamorphosis from nymph to winged adult. Locusts, by contrast, typically have shorter, more conventional grasshopper lifespans, and their populations can surge into swarms when drought paired with vegetation growth creates favorable feeding opportunities. The key contrast is duration and triggering conditions for above-ground life stages. Understanding these life cycles is crucial for predicting population dynamics and potential impacts on agriculture.

Behavior and Signals

• Males of cicadas produce extremely loud sounds using specialized structures on their abdomen to attract mates, a signal that also functions in predator deterrence through sheer numbers and the spectacle of mass emergences. These calls can be heard from quite a distance and are a hallmark of summer in many regions. Locusts communicate and coordinate within swarms through different acoustic and visual cues that help maintain cohesion during migration, with swarming behavior driven by density-dependent phase changes. In short, cicadas rely on loud calls to mate, while locust swarms rely on collective movement and density cues for survival and propagation. This aspect of behavior is essential for understanding how each insect interacts with its environment and other species.

Appearance and Identification

• Cicadas are generally larger, with robust bodies, prominent eyes, and membranous wings that reveal a distinctive veining pattern. Their coloration can vary significantly among species, making them visually striking. Locusts resemble other grasshoppers but may exhibit dramatic color or size changes when shifting from a solitary to a gregarious phase during swarming. This transformation can be quite remarkable and is a key feature of their adaptability. Exuviae (the shed skins left behind after the nymphal molt) of cicadas are often easy to spot on tree trunks, while locust molts are more subdued in the environment due to their ground-dwelling life stages. Identification hinges on family traits and life history rather than a single telltale feature. Being able to identify these insects can help in conservation efforts and pest management.

Ecological and Human Impacts

• Cicada emergences can influence local predator-prey dynamics and nutrient cycling, providing a feast for birds and other animals while temporarily increasing soil aeration and litter input. Their emergence also contributes to the ecosystem by enriching the soil with nutrients. Locust swarms are a well-known agricultural threat, capable of devastating crops over vast areas when outbreaks occur, prompting monitoring and control efforts by agricultural and governmental bodies. The economic impact of locust swarms can be severe, affecting food security and livelihoods. Thus, cicadas and locusts affect ecosystems and human livelihoods in very different ways, rooted in their distinct biology and behavior.

Common Misconceptions

• The terms cicada and locust are often used interchangeably in everyday language, but they refer to different insects with separate evolutionary lineages and life strategies. This confusion can lead to misunderstandings about their ecological roles. Locusts are not a separate species but a behavioral state some grasshoppers adopt; cicadas are a specialized group with unique life cycles and vocalizations. Recognizing these differences helps people understand ecological roles, potential impacts, and appropriate management approaches. Clarifying these misconceptions is important for effective communication about these insects.

Bottom Line

• Cicadas and locusts are not the same thing. They belong to different insect groups, follow different life cycles, and display contrasting behaviors and ecological roles. Clear identification is essential for appreciating their biology and for making sense of their impacts on environments and human activities. This distinction helps avoid alarm or misinformed pest management when either insect appears in local landscapes. Understanding these differences can lead to better coexistence with these fascinating creatures.

Cited context: Distinctions between cicadas and locusts are drawn from general entomological understandings of life cycles, behavior, and ecology, including sources that discuss differences in signaling, swarming behavior, and ecological impacts.^[1][7][9]