Stick Bugs, also known as Stick insects or walking sticks, are one of the insect worlds masters of disguise. Often referred to as ‘nature’s camouflage experts,’ they are truly a wonder in the insect world.
These insects are both numerous and diverse. With approximately 3,000 species worldwide – a number which regularly changes – they belong to the order scientifically known as Phasmatodea in which there are many various families and genera. Some even have subspecies, making them an incredibly diverse group of insects.
Stick insects can be found on every continent in the world except Antarctica and range in size from the miniscule to the massive.
Appearance & Characteristics of Stick Insects
Stick insects are a diverse group when it comes to size. Males are often smaller, and in the case of the tiny Timema cristinae measures just about 0.46 inches. In contrast, the formidable Phobaeticus kirbyi can stretch up to 12.9 inches. Females often outsize their male counterparts.
Their primary colors, green or brown, aid in their camouflage, but nature has painted some of them in brilliant hues or adorned them with stripes. Some are a magnificent blue, which does little to keep them hidden, but is very attractive. While many flaunt wings, others boast spines and tubercles, adding to their unique appearance.
For the vast majority, their uncanny resemblance to twigs and branches is their primary defence mechanism, making them nearly invisible to predators. There is no finer example of nature imitating nature, than with these insects.
Some species have characteristics that provide both Primary Defence (preventative) and Secondary Defence (during an active attack). Camouflage being the main primary defence mechanism, but where this fails, some will open up their bodies as large as they can, flash vibrant colour and/or make a loud, alarming noise to try and scare away their attacker.
Distribution – Location and Habitat
Stick insects predominantly exist in the tropical and subtropical regions around the globe. However, a few adventurous species have ventured into temperate zones. The only continent on which they don’t exist naturally is Antarctica, but you won’t find any living native in the Patagonia region of South America either.
Most species can be found in the northern countries of South America and South-Eastern Asia. Borneo has the most diverse range of anywhere in the world, with over 300 species living on the island.
These insects find solace in forests and grasslands, where they can easily blend with the foliage. Being nocturnal, they prefer to stay hidden under plants during the day, coming out only when the world sleeps.
The Lifestyle & Behaviour of Stick Insects
Mimicry and camouflage are their primary survival tactics. When threatened, many stick insects play dead, hoping to deter their predators. Some even go to the extent of shedding a limb if it means escaping a predator’s grasp!
Many develop growth on their bodies to replicate the plants on which they live, and some can even change colour to match any changes in their environment. Such as when moving to different plants, or changes in season.
Others might use their spiny legs as weapons, swiping at threats. The North American species, Anisomorpha buprestoides, has a unique defense mechanism—it emits a foul-smelling fluid to deter predators.
Others, such as the young nymphs of Spiny Leaf Insects, or Giant Prickly Stick Insects, are known to curl up their abdomen to take on the appearance of a scorpion or an ant. This is another defence mechanism to deter any would be predators from what they might perceive as a more dangerous meal.
Their whole lives seem to revolve around different patters of antipredator behaviours from their eartly nymph stages, right into adulthood.
Diet & Nutrition of Stick Insects
Being herbivores, stick insects have a simple diet: leaves. They are not very picky and will consume a variety of leaves, depending on their habitat. This diet helps them in their camouflage, as consuming leaves often gives them a colour similar to their environment.
Predators & Threats to Stick Insects
Their impeccable camouflage skills mean stick insects have fewer natural predators. Birds, reptiles, and larger insects might sometimes spot and feast on them. Because of the diversity in their range and habitat, the species of predator do change from region to region.
Parasitic Wasps are perhaps their biggest natural enemy. Indeed in some areas where stick bugs infestations are causing harm to some tree species, introducing these natural enemies is one of the methods that have been trialled in an effort to reduce the problem.
Humans pose a different kind of threat. The pet trade has seen a surge in the demand for stick insects, and many enthusiasts even frame their carcasses, similar to butterflies. That being said, the vast majority of stick insects have stable populations.
Stick Insects Reproduction & Lifespan
While they are mostly viviparous insects – reproducing by laying eggs – many species, like the Giant Malaysian Leaf Insect, have evolved to reproduce asexually through parthenogenesis. This means females can lay eggs without needing to mate with males.
The female will usually burry the eggs into a small prepared hole, or onto a leaf directly by using a substrate. Depending on the species, they can lay between 100 to 1000 eggs in a hatch. On average, the eggs take about 20 to 30 days to hatch, but some species can take up to 70 days.
Stick bug species that exists outside the tropics, in the northern or southerly temperate regions can actually pause their development over winter, through a process called diapause. This is a similar process to that seen in some reptile species and mammals such as the polar bear.
After the eggs hatch, stick insects start out as small nymphs and will undergo several molts before taking on their mature adult form. This cycle of development is similar to metamorphosis. After each molt, they shed their exoskeleton and eat it, both for nutrition and to cover their tracks. For most, this process can take several months, but for those with a shorter lifespan, they will take their adult form in a matter of weeks.
In the wild, stick insects can live for up to 3 years, though some species average closer to a few months.
Population Status and Conservation
While many species are thriving, the overall population dynamics of stick insects remain a mystery. With increasing human interference, climate change and habitat destruction, those that live in close proximity to humans are the most likely to encounter problems.
Across the abundant species, the IUCN red list status ranges widely between ‘Data Deficient’ for species such as the Muddy Stick Insect, to ‘Near Threatened’ for species such as the Cigar Stick Insect. For most, there is just not enough information to make accurate statements on security. But for some of those that have well defined habitats, we know the environmental and human impact on these populations.
We know that insect populations in general are in mass decline, so it is only fair to assume that despite the deficiency in data, that this means for stick bugs too.
5 Fun Stick Insect Facts for Kids
- Some stick insects sway back and forth, mimicking a twig moving in the wind.
- They can regenerate lost limbs during their molting process.
- The largest stick insect ever found stretched over 20 inches with its legs out!
- They have been around for a long time, with fossil records dating back to the Early Cretaceous period.
- Some stick insects can produce a defensive spray that can deter predators.
4 Large Stick Insects You Can Keep as Pets
Of all the known species of stick bug out there, around 300 of the different species have been commonly kept in captivity, either in laboratories or as pets. Here are some of the most interesting large examples.
Giant Prickly Stick Insect (Extatosoma tiaratum)
Originating from Australia, the Giant Prickly Stick Insect – also known as the spiny leaf insect – is a favorite among insect enthusiasts. Not to be confused with the Giant Spiny Stick Insect (Eurycantha calcarata) which is native to New Guinea and the Solomon Islands.
Female members of this species can grow impressively up to 6.3 inches. In contrast, males are smaller, measuring around 4 inches. What makes the females stand out is their thick abdomen adorned with thorny appendages, giving them a unique appearance. Males, on the other hand, have a slender build, resembling a twig.
These insects are beginner-friendly, requiring minimal care. Their ease of breeding makes them popular among hobbyists, and observing a colony of Giant Prickly Stick Insects can be a fascinating experience.
Giant Malaysian Leaf Insect (Pulchriphyllium giganteum)
This species is a real masterpiece of nature. Shaped and colored like a leaf, the Giant Malaysian Leaf Insect is a marvel of natural mimicry. They even replicate the veins and color variations found on real leaves.
Adult females can reach a size of 4 inches. Initially, when discovered in 1984, it was believed that only females existed and reproduced asexually (parthenogenesis). However, the first male was identified in 1994. In captivity, you’ll mostly find females that reproduce without males. While they are a sight to behold, they require a bit more care and attention compared to other stick insects.
Metallic Stick Insect (Archrioptera manga)
A native of Madagascar, the Metallic Stick Insect is a shimmering beauty. Its blue metallic hue sets it apart from other stick insects. They can stretch impressively up to 9 inches. Despite their vibrant colors, which often indicate danger in the animal kingdom, they are completely harmless. However, their bodies are adorned with spiny appendages, which can be a bit prickly to the touch.
They’re relatively easy to care for and breed, making them a favourite among those who want a colourful addition to their insect collection.
Malayan Jungle Nymph (Heteropteryx dilatata)
If you’re looking for a sturdy and vibrant stick insect, the Malayan Jungle Nymph is your best bet. Females can grow up to 5.9 inches and have a robust build. Their bright lime or yellowish-green bodies, contrasted with darker red edges, make them a visual delight. The females are adorned with imposing thorns around their bodies and legs.
Despite their intimidating appearance, they’re quite gentle and easy to handle. However, if you’re looking to breed them, patience is key. Their eggs can take almost a year to hatch!