Of all the creatures on the earth, none are more resilient, more stubborn, more tenacious, and more opposed to change than the order of the isopod. While many view the isopods as “the species time forgot,” an isopod can range from a whole variety of niches and evolutionary positions. From detritivores to omnivores, parasites to bottom feeders, aquatic to land-dwelling, the size of a grain of rice to the size of a house cat, this swiss army knife of an order can be found in abundance all across our planet. Isopods can also date all the way back to the Carboniferous Era, around 300 million years ago! This paper will describe the general anatomy of isopods and what makes them all relatives. It will also include the roles that the various isopod species possess within the ecosystems they reside and the unique traits and features of some isopod species, mainly the giant isopod. It will conclude with an overview of the care and keeping of an isopod as a pet and the cultural relevance of this adaptable creature.
Isopods are a form of crustaceans and currently hold the title as the most morphologically diverse of the crustacean orders. They can range in size from microscopic to a yard long. Many people identify isopods with the pillbug, or roly poly. However the pillbug it is not a “bug” in the common sense at all. It is odd to think that a roly poly is more closely related to a lobster than a ladybug. Isopods have an innate ability to thrive in practically every environment, often making adaptations as needed. Pillbugs were once only found in Europe, but due to international trade, they can now be found throughout the world. They have now become instrumental in the proper care of compost and soil.
However, the isopod is not just found on land. They are more commonly found in the sea where they serve a similar purpose to their much smaller relatives by eating away at fish carcuses. The eating habits of the isopod range from constantly snacking all the way to being able to surviving four years without a single bite. This shows the amazing potential for adaptability and evolution that the isopod has achieved.
All isopods have bodies that are segmented into three distinct sections: the head, the pereon, and the pleon. The head has two pair of antenna and a compound eye. One of the only other animals that have been observed to have compound eyes are felines. The compound eyes of the underwater isopod can be so fine-tuned that they can see in pitch black water. They are so sensitive that if they see one glimpse of sunlight it can cause irreparable damage. This makes the transportation of live underwater isopods nearly impossible without causing damage to their ocular nerves. Isopods use the flagellum on their antennae to detect sound and smell. They have a pair of mandibles on their head which are used in the consumption of matter. Their long, chitinous, bodies possess seven perepods on each side which are used as their walking legs. The legs are segmented into six sections. The basis, which is similar to a hip joint connects to the pereon. The ischium, is similar to the femur and connects to the basis. The merus carpus can be seen as the upper and lower knee, respectively and helps to control movement. The final two parts of the perepods are the propotis, which is similar to the human shin, and the dactylus, which comes together in a sharp point and acts as a foot. The rear of the isopod is composed of a short abdominal section known as the pleon and the pleoteson, which joins the pereon and pleon together.
The isopod are rarely observed having any inherent predators. Their thick outer layer deters most forms of attack and their mandibles can cause serious damage if given the chance. However, this does not prevent humans from consuming them as delicacies in certain regions. The isopods prey depends heavily on their niche and habitat. On land they are detrivores, however, in the ocean they appear to be more brazen in their selection of prey. Some isopods can be observed latching onto the outside of fish, like a parasite. Other, smaller isopods, have the fascinating skill of entering a larger fish’s mouth through its gills, eating its tongue. The isopod then locates itself where the tongue once was allowing it to directly eat the food that the fish should be eating without having to do any of the work. It appears that they do not always eat the tongue for sustenance but for tactical reason of getting a few meals out of the fish before it passes.
The Bathynomous Giganteus or giant isopod, is the titans of the isopods. The giant isopod is the most reckless and arguably the coolest of them all. They are the most well-known because of their gargantuan size of around a yard long. They live around 500 meters underwater, traversing the ocean floor. Since resources are scarce on the seafloor, they have adapted for spending incredible amounts of time without consuming any energy. They are in a constant state of partial hibernation, storing a huge amount of energy in the liver to be processed when needed. When the isopod does eat, it stuffs itself. It has been found to be consuming whale caracuses on the sea bed so as to prevent the whale’s remains from muddying the water. They can also munch on slow moving migratory animals such as the sea sponge and sea cucumber. The giant isopod has even been observed attacking live animals. One famous isopod was filmed killing a shark in captivity. Giant isopods have four sets of jaws which are efficient in tearing prey into little bits. Giant isopods are certainly very civil though, always making sure to eat one at a time and never fighting over food. They are also not very picky eaters. Three giant isopods retrieved from the Southern Gulf were found to have injected large amounts of plastics.
Giant isopods have the largest eggs of any marine invertebrates. The females hold 20-30 eggs in a pouch called the marsupian. The male isopods inject his sperm into the female after the female molts. The eggs measure around 51” in diameter. Females do not eat while they are brooding, instead they bury themselves in sediment to save energy and protect the eggs. The manca, or juvenile giant isopods, do not have a larval stage. At birth they are three to four inches long and look exactly like the adult giant isopod. A final fun fact about giant isopod is that they curl up when they are threatened, just like pill bugs.
Many hobbyists have taken to keeping isopods as pets, either as a secondary or primary inhabitant in vivariums. Isopod behavior can be an interesting to observe for enthusiasts. When an isopod is comfortable it moves more slowly. However, when its environment changes due to temperature, humidity, light, or space, it walks more quickly until it reaches a comfortable setting and then slows its pace. Additionally, isopods tend to cluster in groups to conserve moisture. Isopods in captivity tend to eat a wide variety of foods including hand crushed leaves and foods rich in calcium, vitamins, and minerals. The detritus of more complex animals can be consumed by the isopods although that has very few added nutrients. Foods to avoid when caring for an isopod pet are items like fish flakes, rice, cereal, or dog food. Though the isopods can eat all of these they have been shown to cause unwanted results such as attracting flying pests, detritivorous mites, and fungi. Habitats for the isopod pet can either be filled with water or not. The range of different vivarium to house them vary greatly depending on based on the enthusiast’s aesthetic preference.
Isopods have quickly gained a cult following, both here and abroad. Most people who know about isopods only know of their existence from the internet and the various trends they have inspired. Japan, for instance, went through a massive isopod phase when giant isopod phone cases were being sold regularly. Certain Asian countries have gone to eating giant isopods as a delicacy, serving them in a whole manner of different ways. Most patrons say that the giant isopod “tastes like chicken.” Isopods have also had their 15 minutes of fame here in the States. Many memes were created in honor of them, mainly the giant isopod as there is nothing odder than a “giant roly poly.” However, not all of the attention they are getting is positive. Just last year a Melbourne, Australian teen was viciously attacked by a cluster of swarming cirolanid isopods. They chewed up the teen’s legs while he was out swimming. This particular strain of isopods has been observed boring into the hearts of sharks and other huge predators, almost as if to help Mother Nature along with her timing. Probably the most famous isopod in recent history is known simply as “No. 1”. No. 1 was a giant isopod who resided at Japan’s Toba Aquarium. He is known for his hunger strike that lasted five years. During this time he learned to cleverly fool his caretakers into thinking he was eating by toying with the food he was given. He refused to eat a single crumb up until he death in 2015. Little else is know about the Ghandi of the Deep but it is safe to assume that whatever reform he was trying to have pass sadly went unnoticed.
In conclusion, the isopod is the only creature to hold the title of most stubborn and most adaptable at the same time. They have a slew of responsibilities, all of them essential to the wellbeing of our ecosystems. They also have certain distinctions that make them hard to miss. For more information about isopods please refer to any number of the hit songs written about them on the album Songs About Giant Isopods.