Locust swarm. Photo by Laika ac.
Locust swarm. Photo by Laika ac.

Let’s face it: insects rule the world. Insects make up approximately 80% of the world’s species, and at any given time, scientists estimate 10 quintillion (10,000,000,000,000,000,000) individual insects are thriving. By comparison, there’s roughly 7.4 billion humans currently on Earth, so that says a lot about insect dominance.

But, if 10 quintillion insects distributed worldwide wasn’t enough, there are some places in the world where a sizable chunk of these insects gather together in one place or region, forming stupendous swarms. These massive swarms are impressive, but they can also be devastating. Let’s take a look at some of the biggest swarms in the world.

Bees

Honeybee swarm. Photo by Sichy007.
Honeybee swarm. Photo by Sichy007.

When we think of “swarms”, bees are often at the top of the list. They are colonial in nature, and when threatened, they will attack in great numbers. But bees are among the most beneficial species on this list, pollinating flowers and producing honey. As humans, we rely on bees tremendously.

Nevertheless, bees can be quite dangerous, especially for those who are allergic to their painful stings. In New York City, urban beekeepers are raising millions of bees, and inevitably, amateur beekeepers are allowing some of them to escape. This has caused a multitude of problems, where 10,000 or more bees have swarmed onto stops signs, SUVs, and other objects around the city.

Cicadas

Cicada swarm. Photo by Greg Hume.
Cicada swarm. Photo by Greg Hume.

Cicadas are insects often associated with warm weather, especially the heat of summer. That’s because, in more temperate parts of the world, certain species of cicada live underground for over a decade until they emerge and reproduce in the warmer months.

In the northeast United States, these periodic cicadas are quite common and individual cicadas emerge every 17 years. So, every summer, cicadas that were born 17 years prior finally emerge from the soil and become adults. When this happens, billions of cicadas emerge at once, and the swarms are quite impressive (and loud). In some areas, they can reach 1.5 million cicadas an acre!

Luckily, aside from making a tremendous din, cicadas are not pests. They don’t eat crops (although they occasionally feed upon tree sap); they just want to have sex and die. That’s the whole reason why they’re so loud. Males produce the loud sounds to attract females!

Ants

Argentine ants accessing trap. Photo by Thmazing.
Argentine ants accessing trap. Photo by Thmazing.

Ants are definitely form huge swarms. There is no question about that. But what’s truly impressive about ant swarms is their complexity. Typically, ants form colonies that can consist of millions of individuals, but with the help of humans and global transportation, various species of ants have taken colonialism to the next step.

Much like the colonial empires built by humans, ants have spread across the globe to build their own empires, which are known as supercolonies. For example, Argentine ants are present on nearly every continent, spreading from South America to North America and Europe as well as Japan, Australia, New Zealand, and Hawaii. In the Mediterranean region, one supercolony of Argentine ants encompasses over 3728 miles (6000 kilometers)!

Of course, this can be a huge problem for native species and humans, especially if the ant species are aggressive. Invasive ant species, such as Argentine ants, red fire ants, and yellow crazy ants, are fine in their natural range, but outside of that, they devour native species and invade human residences in huge numbers.

Mayflies

Mayfly swarm. Photo by Kovacs.szilard.
Mayfly swarm. Photo by Kovacs.szilard.

Mayflies are synonymous with “swarm”. Since they spend 99% of their lives as aquatic nymphs underwater, mayflies are generally only seen in their swarming adult form. But, when they do swarm, they blanket the landscape and the sky.

Like the periodic cicadas, which emerge in great numbers from the soil during the warm months every year, mayflies emerge in great numbers from lakes, rivers, and streams. Their adult forms do not have mouthparts, so they cannot feed and, therefore, are not destructive to crops. Instead, they solely exist to have sex and die, which is not unlike the adult cicada’s life cycle.

In North America, every year, the species Hexagenia limbata hatches in great numbers. In this hatch, the total number of mayflies is estimated to be around 18 trillion. That’s more than 3,000 times the number of people on Earth!

Locusts

Plague of locusts on the move. Photo by CSIRO Science Image.
Plague of locusts on the move. Photo by CSIRO Science Image.

Of all insect swarms, the most infamous is the locust. In fact, a swarm/group of locusts is collectively called a “plague”. This name is based off the Biblical passage in which Yahweh unleashed a plague of locusts upon the Egyptians to punish them for enslaving the Israelites.

Of course, even in modern times, a plague of locusts is incredibly destructive, and they can ravage crops. Unlike mayflies and cicadas, which are more interested in sex than food, locusts are VERY hungry, and they devour everything in their wake. This is compounded by the fact that locus swarms are the biggest on Earth.

The Desert locust, Schistocerca gregaria, forms the largest of all insect swarms. In 1954, a swarm in Kenya covered an area of 200km2. The density was estimated at 50 million individuals per km2, which gave the swarm a total number of 10 billion locusts!!!