Brood XI facts for kids

Brood XI (also called Brood 11) was a group of periodical cicadas that used to appear regularly in the eastern United States. Periodical cicadas are special insects that spend most of their lives underground. They only come out every 13 or 17 years. Brood XI was one of the smallest groups of 17-year cicadas. It was made up of only one type of cicada, called Magicicada septendecim.

This group of cicadas was mostly found in parts of Connecticut, Massachusetts, and Rhode Island. These areas were at the very northern edge of where this type of cicada could live. Brood XI has not been seen since it last appeared in 1954. Because of this, scientists believe it is now extinct.

What are Periodical Cicadas?

Periodical cicadas are unique insects. They are known for their very long life cycles. Most of their lives are spent underground as nymphs. They feed on the sap from tree roots. After 13 or 17 years, they dig their way out of the ground. They then turn into adult cicadas. These adults live for only a few weeks. During this time, they mate and lay eggs. Then they die. The new eggs hatch, and the young cicadas go underground to start the cycle again.

When many cicadas come out at the same time, it is called an "emergence." A "brood" is a specific group of cicadas that emerge in the same year.

Brood XI's Past Appearances

People have reported seeing Brood XI cicadas for a long time. Records go back to the 1700s. For example, they were seen in Sandwich, Massachusetts. In 1835, a person named E. C. Herrick saw them "swarming" in the woods of Tolland County, Connecticut. This means there were very many of them.

By the late 1800s, it became harder to find records of Brood XI. An entomologist (an insect scientist) named George Dimmock saw many of them in Suffield, Connecticut in 1869. He even collected a cicada specimen. But when he looked again 17 years later in the same spot, he could not find any.

In 1903, another scientist, Prof. Alpheus Spring Packard, reported Brood XI in three places in Rhode Island. In one town, Coventry, Rhode Island, the cicadas covered scrub oak trees for a long distance. But when scientists searched again in 1920, they found nothing. By the 1920s, many people thought Brood XI might have already disappeared.

Rediscovery in 1937

To the surprise of many scientists, Brood XI was found again in 1937. Prof. Jerauld Manter from the University of Connecticut heard about cicadas near Willington, Connecticut. This was on June 7, 1937.

When he visited, he found what looked like a healthy group of cicadas. They were in a pasture east of the town. Manter noted that people had heard cicadas in that area in 1903 and 1920. He saw thousands of cicadas on trees. The group covered about 10 acres. However, he also thought that this group was probably "the last remnant" of Brood XI. This meant it might be the only part of the brood left.

The Last Sighting in 1954

The very last time Brood XI cicadas were seen was in 1954. Prof. Manter visited the same spot again. He saw cicadas starting on June 10. But he noticed there were far fewer cicadas than in 1937.

Later that summer, he looked for signs of new eggs. Cicadas lay eggs in tree twigs, which can make the twigs wilt. Unlike in 1937, he found no signs of egg laying or wilting twigs. This led him to believe that the cicadas were close to disappearing forever.

In 1971, scientists searched the same place again. They found no cicadas at all. No one has seen Brood XI since then. Scientists believe that changes to their living areas and other environmental problems caused the brood to become extinct. These areas were already at the edge of where the cicadas could survive.

Could Brood XI Still Exist?

In 1988, an amateur insect enthusiast thought they saw Brood XI near Chaplin, Connecticut. This was close to the Natchaug State Forest. However, this report was later found to be incorrect.

Even though most people think Brood XI is extinct, some scientists still have a small hope. David Marshall from the University of Connecticut has said he "would not be surprised if there are small patches of [Brood XI] that have been missed." He believes this because much of southern New England is not very densely populated. This means there are still many wild areas where a small group of cicadas could live unnoticed.