National Geographic Interactive - 02.2020

Extensor muscle

( jumping)

FEMUR

Solitary femur

18% greater volume

Flexor muscle

(bending)

Antenna

Antennal lobe

(smell)

Brain

Eye

Frontal view

FLYING
GREGARIOUS
ADULT
2.5x size

GREGARIOUS

NYMPH

Optic

lobe

(sight) Midbrain

(general

processing)

Foraging

nymphs

Pearl millet

Pennisetum

glaucum

Solitary vs. gregarious brain

Breeding and feeding frenzy

Returning rains provide moist breeding

grounds. New generations form groups

that forage in unison. Once their wings

grow, the herds become flying swarms in

search of more food and habitat.

Flying apocalypse

Although uncommon, a major plague

begins when swarms, often traveling 30 to

60 miles a day, develop over multiple re-

gions. Without intervention, plagues can

last years, until natural die-off occurs.

34

THE DESERT LOCUST

The species with the most economic

impact, the desert locust, threatens one-

fifth of Earth’s land area and one-tenth of

the global population. Over 60 countries

are susceptible to swarms. Locusts in the

solitary phase occupy and breed in smaller

regions. The last major plague, from 1986

to 1989, hit North Africa and the Middle

East. Many swarms died while crossing the

Atlantic; some reached the Caribbean.

RILEY D. CHAMPINE, NGM STAFF. SOURCES: STEPHEN ROGERS, UNIVERSITY OF CAMBRIDGE;

STEPHEN J. SIMPSON, UNIVERSITY OF SYDNEY; KEITH CRESSMAN, FAO DESERT LOCUST INFORMATION SERVICE

A toxic new look

Swarming locusts turn

bright yellow—a warning

to birds, reptiles, and other

predators that they may be

unappetizing or poisonous.

Brain boost

Transition to the gregarious

phase causes the brain—espe-

cially the midbrain—to grow

larger, perhaps for more com-

plex information processing.

Increased endurance

Offspring of gregarious

locusts develop smaller

femurs. Their hops are

shorter but use less energy

to cover the same distance.

ATLANTIC

OCEAN

INDIAN

OCEAN

EUROPE

ASIA

AFRICA

Desert locust

Schistocerca gregaria

Solitary range

Swarming range

Swarm reports

1985–2019