Environment

What Factors Triggered the Extinction of the World's Largest Earwig?

Habitat loss and predation by invasive species are considered the primary causes of the extinction of the Saint Helena earwig.

The World’s Largest Earwig

The largest earwig species ever recorded was the Saint Helena earwig, which could grow up to 3.3 inches in length. The species had a long, dark brown-black colored body with reddish colored legs. It had six legs located on the front portion of its body and was characterized by a large, forked tail, often referred to as a pincher. The Saint Helena earwig, also known as the giant earwig or the Saint Helena striped earwig, could be found on the island of Saint Helena in certain forests, plains, and near seabird colonies on rocky outcroppings. Researchers identified three specific areas that this species inhabited: the Prosperous Bay plain, the Horse Point plain, and the dry areas of the eastern region of the island. Informally, the Saint Helena giant earwig is sometimes called as the “dodo of the dermapteran,” a name that refers to the order of insects to which the species belonged.

Earwigs are an interesting insect species due to their social behavior. Unlike most insects, which are often solitary creatures that care for and provide for themselves, earwigs exhibits familial recognition. This behavior is most noteworthy in earwig mothers, who care for their young in a number of ways, including keeping and protecting the nest of eggs, cleaning the nest and eggs, assisting baby earwigs during the hatching process, feeding young earwigs, and sleeping with baby earwigs in a communal nest. Earwigs typically construct their shelters underground in long and deep tunnels. Researchers report that most earwig species only leave these underground shelters after long periods of rain, and can be spotted on the ground at night.

Discovery of the World’s Largest Earwig

A Danish entomologist was the first scientist to ever collect this species in 1798 in the Saint Helena, a tropical island in the Atlantic Ocean. Despite its record-breaking size, the Saint Helena earwig did not receive attention again until 1913, and then again in 1962, from two ornithologists. The Saint Helena earwig did not receive its scientific name, L. herculeana, until 1965, when it was discovered that the specimen had previously been confused with the L. loveridgei species. Some researchers speculate that this species was largely ignored due to a broad disinterest in earwig species, its confusion with another earwig species, and because it was an endemic species that could only be found on the island of Saint Helena.

An increasing interest in the areas of nature, biodiversity, zoology, and environmental conservation led to a slightly increased interest in this species. Beginning in the 1960’s, more researchers began searching for the Saint Helena earwig, however these efforts were largely unsuccessful. The last sighting of the species was recorded in 1967. In an attempt to publicize its conservation status, the local government designed and released a collectible stamp with an image of the giant earwig in 1982. Just six years later, the London Zoo financed an exploration project in what was one of the final attempts at obtaining a live specimen. Subsequent searches were conducted in 1993 and 2003.

Factors Leading to Extinction of the World’s Largest Earwig

In November of 2014, the International Union for the Conservation of Nature (IUCN) categorized the Saint Helena giant earwig on its Red List as officially extinct. While the organization acknowledges that the insect species may still exist in a very remote location on the island, it stated that all scientific evidence indicates that the insect is extinct. Experts in the field of entomology believe that two factors ultimately led to the extinction of the world’s largest earwig: invasive species and habitat destruction.

Invasive Species

An invasive species is somehow introduced to an ecosystem where it is not considered a native species. Many invasive species are introduced to ecosystems by humans, either intentionally or unintentionally, while others independently migrate to and colonize a new home.

Scientists believe that the Saint Helena giant earwig was forced to compete for survival against several invasive species, including spiders, centipedes, mice, and rats. It is believed that all of these species relied on the giant earwig as a dietary source. In particular, the Scolopendra morsitans centipede was likely the biggest challenge to the giant earwig, providing competition for food and habitat.

Habitat Destruction

Another common factor in the endangerment and extinction of a vast number of animal species is habitat destruction. Habitat destruction occurs when external forces render an ecosystem unfit for the life it once sustained. This factor may be caused by natural occurrences, like flooding or storms, or by human activity, like deforestation and agriculture.

The Saint Helena giant earwig was threatened by two specific instances of habitat destruction, both caused by humans. The first was the deforestation of the gumwood forests, where it was known to inhabit. These forests were destroyed to make way for agricultural endeavors and to clear space for sprawling urbanization. Additionally, the construction industry harvested rocks from coastal areas of the island in order to keep up with increasing demands in development. These coastal rocks housed colonies of both the seabird and the Saint Helena giant earwig.

Lack of Attention Surrounding Its Extinction

Most people can cite at least a few animal species that are either endangered or already extinct, the vast majority of which will be charismatic species, meaning they are easily recognizable and often considered attractive to look at. Some examples of charismatic endangered species include pandas, tigers, and elephants. The general public is less likely to recognize insects or consider their potential extinction.

Given this lack of attention given to insect species, the extinction of the Saint Helena giant earwig was only published in a few media reports. This lack of coverage means that many individuals are still unaware of its conservation status. Critics claim that conservation groups also tend to ignore the plight of insects, focusing instead on bird and mammal species. In fact, the IUCN has identified and recorded the conservation statuses of approximately 100% of identified mammal and bird species in the world and less than 1% of global insect species. However, insects are important in maintaining the balance within ecosystems.

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