Physical characteristics of stick insects
- skin type
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Stick insects have evolved a remarkable ability to blend in with their surroundings.
Slow, sedentary and wary of predators, the humble stick insect strives to be as inconspicuous as possible. Thanks to one of the most effective camouflage systems on the planet, even determined and keen predators have a hard time spotting stick insects in the wild. Its camouflage system sometimes makes it look like a walking plant!
3 unbelievable facts !
- Stick insects are among the longest insects in the world. The stick insect found in China in 2014 measured 24.5 inches (62.4 cm)!
- Certain species of stick insects can reproduce without a mate. This form of reproduction is known as parthenogenesis and produces an exact duplicate of the mother!
- It is estimated that there are more than 3,000 species of stick insects worldwide! As recently as 2019, scientists discovered two brightly colored species in Madagascar.
scientific name and history
The scientific name of the stick insect order is Phasmatodea , which is derived from the Greek word phasma, meaning ghost, apparition or ghost. This is reflected in the animals' strange ethereal disappearing behavior. Because stick insects represent an entire order (a major taxonomic level below Insecta), stick insects encompass a truly large number of species. It is estimated that there are more than 3,000 species of stick insects worldwide!
Given how little is known about stick insect evolution, their taxonomic system is still in flux. Scientists are working on how to classify all stick insect species into different biological families. What is known is that the first identifiable members of its class arose approximately 201-145 million years ago. Modern prototypes appeared 145-66 million years ago.
appearance and behavior
A stick insect's entire life is devoted almost entirely to crypsis' unique strategy: the ability to blend into its natural environment, which may include different kinds of bark, moss, leaves, lichens, and twigs. What sets the stick insect apart from other mimic species, however, is that its camouflage is more than just an outward affectation. The insect actually camouflages itself as a twig or leaf of its host plant. Evidence suggests it has even honed its ability to mimic the motion of a tree branch swaying in the wind to fend off particularly keen predators.
Given the large number of species within the Fusaridae order, stick insects can exhibit a variety of morphological sizes. The smallest known species — Timema cristinae in North America — is just half an inch across, according to National Geographic. The largest species – the daunting Phryganistria chinensis Zhao in China – is more than two feet long! Just for comparison, a typical adult foot is about 12 inches long. Stick insects are sexually dimorphic, so on average, females are considerably larger than males.
Despite the wide variation in size between species, stick insects do share many common features, including elongated antennae, compound eyes, cylindrical or flattened bodies, multiple movable mouthparts, segmented legs, and short or Highly shrunken wings. While typical stick insects look fairly drab green or brown, certain species are wrapped in bright and conspicuous shades of yellow or red to signal to predators how unappetizing their taste is. In fact, the males of a new species recently discovered in Madagascar turn blue during mating season.
Some truly bizarre stick insect species display a variety of unexpected traits, including well-developed wings, sharp spines on the legs, false buds, lichen-like growths, and the ability to change pigmentation to adapt to their surroundings. These defense mechanisms are tuned to help it live a life of relative solitude in harsh environments.
Stick insects are widely distributed in temperate, tropical and subtropical regions of all continents except Antarctica. They live almost exclusively in grasslands, woodlands, and forests. The greatest number of stick insect species are found in South America and Southeast Asia, but a disproportionate number appear to occupy the large island of Borneo in the Pacific Ocean. Borneo is home to a wide variety of rare and diverse animal species, many of which are found nowhere else in the world.
In order to avoid predation, stick insects are mainly nocturnal in nature. They spend most of their time lying motionless on or under plants, only coming out to feed at night. Many species seem to be well adapted or at least to some extent selected for their host plants (which also tend to serve as food sources).
Regardless of the species, all stick insects share a common preference for leaves. Their powerful mandibles are perfect for carving and cutting away the tough exterior of plants, making them easier to eat. Some evidence suggests that the stick insect is an integral part of local ecosystems as it removes and recycles old plant material. Their feces also contain enough digested plant matter to be a food source for other animals. However, if the stick insect is present in sufficient numbers, it can cause severe foliage loss in localized areas. This could damage local nature reserves and parks in some parts of the world.
Predators and Threats
Stick insects are low on the food chain. It is constantly at risk of becoming prey for birds, primates, reptiles, spiders, small mammals and even other insects. Bats are perhaps the most dangerous predators. Their echolocation easily negates the insect's greatest strengths, its camouflage and sneakiness.
If its shell is blown, the stick insect may fall back on another of its many defense mechanisms to deter a hungry predator. While each species may be different, common traits may include sharp spines used to attack predators, noxious odors expelled from glands, and even nasty chemicals in the blood, which it forces through the exoskeleton seam. Some species have the ability to detach or amputate limbs at joints where they are grasped by predators. This phenomenon, known as limb autotomy, is only a temporary setback, as the insects regrow the missing limb over time.
If all else fails, the stick insect may resort to the ever-proven tactic of trying to startle or scare away predators by being loud or aggressive. The presence of colored wings or unusual features can enhance the effectiveness of this display. If the predator is momentarily confused, the stick insect will drop off and hide in the bushes to evade detection.
Despite their global ubiquity, stick insects can be vulnerable to habitat destruction, pesticide use, and human encroachment. Without the protection of plants or trees, stick insects are vulnerable to predators.
Reproduction, Babies and Longevity
Reproduction of stick insects is perhaps the most complex aspect of their existence. Reproduction begins with long and protracted courtships that may last days or even weeks at a time. During these uninterrupted mating sessions, the insects will remain attached to each other and rarely let go. Because stick insects don't necessarily rely on visual cues, they release chemicals in the air to attract mates.
Many stick insects have the remarkable ability to produce female offspring from unfertilized eggs in the absence of any males. This type of asexual reproduction is called parthenogenesis. It produces an exact copy of the mother. While some species may prefer to reproduce almost exclusively this way, breeding methods are known to fluctuate within populations over time. The origin of sexual reproduction is unknown, so the emergence of parthenogenesis as a reproductive strategy is a highly unusual phenomenon that has aroused the curiosity of many scientists.
Regardless of the reproductive utility of parthenogenesis, a single female stick insect can eventually lay hundreds of eggs in a short period of time. Because eggs are highly vulnerable to predators, stick insects have evolved a variety of strategies to deal with the threat. Females may choose to place each egg far apart on the ground below, or lay eggs in hard-to-reach discrete hiding spots, or even attach the eggs to leaves or plants.
One particularly remarkable strategy deployed by some species involves a mutually beneficial relationship with ants. The ants, attracted by the nutritional value of the surface fat capsules, actually carry the unhatched eggs back to their nest, protecting it from predators. Young stick insects will leave the ant colony after hatching. Despite these protective measures, many eggs are lost to predators.
Stick insects rely on a method of reproduction called hemimetabolic. This is an incomplete form of metamorphosis in which the insect's life cycle goes through three distinct stages. The first stage of the life cycle occurs entirely within the egg, with developmental cycles ranging from a few months to a year.
Once a stick insect emerges from its egg, it begins the second stage of its life cycle: the nymph stage, in which the insect resembles a young version of a mature insect. The stick insect can't transform all at once — it lacks the pupal stage common to many other insects — so the larva must grow gradually through a series of intermediate stages to reach full maturity. At various times throughout the process, the insect sheds the old exoskeleton and then creates a brand new one. The time between molts is called the first instar.
The nymph does not simply discard its old exoskeleton, but continues to consume it. This is done for two reasons. First, the exoskeleton is an excellent source of protein. Second, the insect can hide all evidence of its molting from observant predators.
After several molts, the stick insect will eventually enter its third and final adult stage. It takes about three months to a year to reach this mature stage. If a stick insect survives to adulthood, its average lifespan is generally between two and three years.
Phasmatodea are found in large numbers all over the world. While the vast majority of stick insect populations remain healthy, a significant number are critically endangered. Of all the endangered stick insects, perhaps the most famous is Dryococelus australis – commonly known as Lord Howe Island stick insect or tree lobster. The species once thought to be extinct was rediscovered in 2001. Now Melbourne Zoo, San Diego Zoo and other zoos around the world are slowly bringing it back from the brink.
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Stick Insect FAQs (Frequently Asked Questions)
Can Stick Insects Hurt You?
Stick insects do not pose much danger to humans. However, especially if you plan to keep one as a pet, it is still wise to treat it with caution. Some species have sharp spines that may suck blood. Even rarer are the stick insects, which release a chemical that causes burning or stinging in the eyes or mouth. They are mostly confined to a few regions of the world, such as Peru.
Where do stick insects live?
Stick insects spend the vast majority of their lives in plans and trees, which they depend on for subsistence, protection and reproduction.
What is the evolutionary history of stick insects?
From the limited evidence in the fossil record, stick insects appear to have evolved to mimic their surroundings at least 126 million years ago. This occurred around the same time as the earliest birds and mammals evolved, which may indicate that insects evolved camouflage to avoid detection by visually-oriented predators. The three unearthed 126-million-year-old fossils look similar to ginkgo leaves that originated in China and Mongolia, around the same time. In a curious evolutionary quirk, there is evidence that stick insects lose and then partially regain their wings.
Can stick insects be kept as pets?
Stick insects are kept as pets. In general, stick insects are pretty much harmless (see the FAQ on "Can stick insects hurt you?" above), won't infest a house if they escape, and have a limited lifespan. Importantly, stick insects can cause ecological damage if introduced into non-native areas. Therefore, if you plan to keep stick insects as pets, exercise caution and do not introduce them to new environments as a non-native species.
Are stick insects herbivores, carnivores, or omnivores?
Stick insects are herbivores, which means they eat plants.
To which kingdom do stick insects belong?
Stick insects belong to the animal kingdom.
What kind of stick insects are they?
Stick insects belong to the class Insecta.
What order do stick insects belong to?
Stick insects belong to the order Phytophthora.
What type of mulch do stick insects have?
Stick insects are covered in shells.
What do stick insects eat?
Stick insects eat leaves, plants and berries.
Who are the natural enemies of stick insects?
Natural enemies of stick insects include birds, rodents, and reptiles.
What is the average litter size for stick insects?
The average litter size of stick insects is 1,000.
Any fun facts about stick insects?
There are more than 3,000 species of stick insects!
What is the scientific name of stick insects?
The scientific name for stick insects is stick insects.
How many species of stick insects are there?
There are 3,000 species of stick insects.
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- David Burnie, Dorling Kindersley (2011) Animals, The Definitive Visual Guide to the World's Wildlife
- Tom Jackson, Lorenz Books (2007) Encyclopedia of World Animals
- David Burney, Kingfisher (2011) The Animal Encyclopedia of Kingfishers
- Richard Mackay, University of California Press (2009) Atlas of Threatened Species
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