Difference Between Locusts and Cicadas

Main Difference – Locusts vs Cicadas

Locusts and cicadas are two types of invertebrates found in the environment. Both locusts and cicadas are large insects, feeding on plants. Both insects are capable of making noise to attract female insects. But, cicadas are considered as the loudest insects. The main difference between locusts and cicadas is that locusts are a group of grasshoppers, which reach a swarming phase whereas cicadas are a family of true bugs with sucking mouth parts. 

Key Areas Covered

1. Locusts – Facts, Characteristics, and Behaviour
      – Definition, Features, Significance
2. Cicadas –  Facts, Characteristics, and Behaviour
      – Definition, Features, Significance
3. What are the Similarities Between Locusts and Cicadas
      – Outline of Common Features
4. What is the Difference Between Locusts and Cicadas
      – Comparison of Common Features

Key Terms: Annual Cicadas, Acrididae, Cicadas, Cicadidiae, Gregarious Phase Locusts, Insects, Locusts, Locusts Swarms, Magicicada, Periodical Cicadas, Plague, Proto-Periodical Cicadas, Solitary Phase Locusts

Locusts – Facts, Characteristics and Behaviour

Locusts are short-horned grasshoppers belonging to the family Acrididae. Typically, locusts are solitary. But, they can increase in number, changing their behavior and the habitat to become gregarious. The gregarious phase of locusts is referred to as the swarming phase. The sporadic appearance and disappearance of locust swarms are described by the phase theory. Both solitary and gregarious phases of the plague species can be differentiated by the coloration, form, physiology, and behavior. In the solitary phase, locusts have a color, matching their surroundings and they live individually. These types of locusts are less active and have low metabolic rates. The wings of the solitary phase nymph are short and they have long legs, narrow pronotum, and a large head. The solitary phase adult locust is shown in figure 1.

Figure 1: Locusta migrotoria (solitary phase)

The adults in solitary phase have long wings, broader shoulders, and saddle-shaped pronotum. When many solitary phase locusts are present, these locusts undergo physiological changes and produce offspring of gregarious phase. The gregarious locusts have a black and yellow or orange coloration in a pattern and they gather in a large group. These types of locusts are very active and they have high metabolic rates. After producing a dense population of locusts, the majority of the local population shifts to gregarious migratory phase. Again, the gregarious phase locusts produce an offspring of solitary locusts. The formation of gregarious phase locusts is a physiological response of locusts to violent fluctuations in the environment. The long distance dispersal of locust swarms occurs with the help of the front winds of the storms or high-level jet stream winds.

Figure 2:  Locusta migrotoria (gregarious phase)

The control of the locust plague is almost impossible. Still, by applying insecticides, using insecticidal baits and hopperdozers and destroying egg masses, the plague can be controlled. The gregarious phase locust is shown in figure 2. 

Cicadas – Facts, Characteristics, and Behaviour

Cicadas are a type of insects, whose male insects make buzzing and clicking noises by flexing their tymbals. The tymbals are drum-like organs found in the abdomen of the insect. The smooth muscles connected to the tymbals pull the tymbals in and out rapidly, making a noise. The noise is intensified by the abdomen of the insect. The majority of cicadas are found in the family Cicadidiae. The cicadas are the actual cousins of crickets. The cicadas have a beak, which can be used to suck fluids in the xylem of plants. The female cicadas produce rice-shaped eggs. Once the eggs hatch, the cicada that comes out looks like a small white ant. The cicada lives underground, feeding root sap around 2 to 17 years. After that, the cicadas nymph emerges and sheds its exoskeleton. Then the adult skin is hardened and new wings emerge from the body. The adult cicada is referred to as imagoes. A cicada nymph is shown in figure 3.

Figure 3: Cicada nymph

The life cycle of the cicada can be found in three types; annual, periodical, and proto-periodical. In every year, swamp cicadas emerge in the United States and Australia at the beginning of the summer. The periodical cicadas such as Magicicada septendecim emerge every 17 years. The proto-periodical cicadas are a type of annual cicadas, but many years, they emerge in large numbers.

Figure 4:  Magicicada

Over 3,390 species of cicadas can be identified around the world. The largest species of cicadas is Magicicada septendecim and it is native to Malaysia. The loudest cicada is Neotibicen pronotalis found in North America and it can achieve 108.9 decibels. The Magicicada is considered as the long lived periodical cicada, which is found in Georgia, North and South Carolina. The Magicicada is also mistakenly known as locusts. An adult Magicicada is shown in figure 4. 

Similarities Between Locusts and Cicadas

• Both locusts and cicadas are two types of large insects, which are herbivores in the diet.
• Both locusts and cicadas have three pairs of legs.
• Both insects are capable of producing sound.
• Both locusts and cicadas can be solitary creatures.
• Both can undergo a swarming phase.

Difference Between Locusts and Cicadas

Definition

Locusts: Locusts are large, tropical grasshoppers, that are typically solitary, but from time to time, they migrate as vast destructive swarms.

Cicadas: Cicadas are large homopterous insects with long transparent wings, whose male insect produces a loud noise.

Family

Locusts: Locusts belong to the family  Acrididae.

Cicadas: Cicadas belong to the family Cicadidiae.

Order

Locusts: Locusts belong to the order Orthoptera.

Cicadas: Cicadas belong to the order Hemiptera.

Average Lifespan

Locusts: The average life span of the locusts is several months.

Cicadas: The average life span of cicadas is up to 17 years.

Size

Locusts: Locusts are 0.5 to 3 inches long.

Cicadas: Cicadas are 0.75 to 2.25 inches long.

Mouth Parts

Locusts: Locusts comprise chewing mouth parts.

Cicadas: Cicadas comprise proboscis in their mouth to suck fluids of plants.

Legs

Locusts: Locusts have one pair of long, hind legs.

Cicadas: Cicadas have three pairs of legs in the same length.

Wings

Locusts: Locusts have two pairs of wings.

Cicadas: Cicadas have long transparent wings.

Feed on

Locusts: Locusts feed on crops.

Cicadas: Cicadas feed on the xylem of plants.

Destructive Plagues

Locusts: Locusts produce destructive plagues.

Cicadas: Cicadas do not produce destructive plagues.

Noise

Locusts: Locusts make noise by vibrating the hind legs against their forewings.

Cicadas: Cicadas make noise with the aid of tymbals.

Conclusion

Locusts and cicadas are two types of noise making insects, which produce swarming phases. However, the swarming phase of the locusts is a destructive plunge. The locusts are like grasshoppers and cicadas are like crickets. The main difference between locusts and cicadas is the behavior of each insect in their swarming phase.

Reference:

1. “Locust.” Encyclopædia Britannica. Encyclopædia Britannica, inc., n.d. Web. Available here. 16 July 2017. 
2. “Cicada News, Facts, Lifecycle & Sounds.” Cicada Mania. N.p., n.d. Web. Available here. 16 July 2017. 

Image Courtesy:

1. “Locusta migratoria” By Matsumomushi – Self-photographed (Public Domain) via Commons Wikimedia
2. “Locusta migratoria (gregarious phase) (5012171245)” By Gilles San Martin from Namur, Belgium – Uploaded by Jacopo Werther (CC BY-SA 2.0) via Commons Wikimedia
3. “A Cicada nymph sits on leaf before hibernating for 16 years” By USDAgov – (Public Domain) via Commons Wikimedia
4. “In the early spring of 2013 the eastern half of the U.S. will see and hear the emergence of the 17-year Cicada (Magicicada) (Pic 2)” By USDAgov – (Public Domain) via Commons Wikimedia