Every year in the last two weeks of August, the Pacific National Exhibition (or PNE) in Vancouver holds a fair. Although at heart the event is an agricultural fair, it offers a lot more to see than just farm animals. One of the attractions at a recent fair was an exhibition of giant invertebrate models, some of which were animatronic. Observing the exhibition was a fun way for people to learn a little about nature. In this post I share some of my photos of the models as well as facts about the real animals.

The exhibition was named Xtreme Bugs. The name was catchy, but the models represented arthropods and not just bugs. Many people use the word “bug” to mean insect, but the models included a centipede, a spider, a scorpion, and a vinegaroon or whip scorpion, which are not insects. (I’ll write about the spider and the vinegaroon in a future post.) Insects, centipedes, spiders, scorpions, and vinegaroons are invertebrates belonging to the phylum Arthropoda. Arthropods have an external skeleton, or an exoskeleton, as well as a segmented body and jointed appendages.

The Orchid Mantis

The orchid mantis (Hymenopus coronatus) is a beautiful animal that lives in Southeast Asia. The female has a colour that is some combination of pink, yellow, pale green, brown, and white. The colouration varies and is different in the juvenile stage of the mantis and the adult. According to some photos that I’ve seen, the juvenile female looks pinker than the adult one.

The females develop a colour, form, and posture that disguise them from humans as they hide amongst flowers of orchids and other types of blossoms. They sometimes pose on leaves, where they may look like a flower attached to the leaf. The upper part of their back legs are flattened and petal-like, adding to the illusion that they are part of a flower.

The males are much smaller than the females and are brown in colour. They tend to hide more than the females. The appearance of the females means that they don’t have to hide and helps them to catch insects that approach the flower. There is a debate about whether a female is completely disguised, stopping other insects from realizing that she’s present, or whether part of her body is actually used to attract the insects by mimicking something that’s useful to them.

As can be seen in the two photos of real orchid mantises shown below, the first one has a lot of pink on its body while the second one (which was identified as an adult) doesn’t. The second mantis is located approximately in the centre of the photo.

The Peruvian Giant Centipede

Scolopendra gigantea (the Peruvian giant centipede) may reach a length of twelve inches or occasionally even longer. It’s found in South America and the Caribbean and lives in tropical and subtropical forests.

The living animals are red-brown or orange-brown in colour and are carnivores. The model shown below has large fangs that don’t look quite like the real version. The fangs of a real centipede can be seen in the photo of the preserved animal. The two fangs work like pincers.  They are used to attack the prey.

The body of a centipede contains multiple segments and is flattened. Each segment bears a pair of legs. Despite the name “centipede”, no centipede has a hundred legs. The animals always have an odd number of leg pairs.

The pair of legs just behind the head of a centipede have become modified to form the fangs (or forcipules), which inject venom into the prey. The last pair of legs are long and have become sensory structures. The animal has a pair of antennae on its head, which are also sensory structures.

Like all centipedes, the Peruvian giant centipede produces venom and injects it into its prey as it bites. It produces far more venom and eats larger animals than the more familiar house centipede. The bites of small centipedes are unlikely to harm humans, though they may be felt, but the bite of the giant centipede can sometimes be dangerous. The animal eats other arthropods, frogs, lizards, and even small mammals like mice.

The African Fat-Tailed Scorpion

The African fat-tailed scorpion (Androctonus australis) lives in deserts of North Africa, the Middle East, India, and Pakistan. It has a thick and powerful tail. It doesn’t dig a burrow but hides in natural crevices when necessary. The model accurately depicts the strange tail that looks as though it’s decorated with beads or stitches. It also gives an accurate depiction of the curved stinger at the end of the arched tail.

Researchers have found that the scorpion often stays on the surface of the sand as a windstorm arrives instead of seeking shelter. Its exoskeleton apparently isn’t harmed by the force of the sand hitting it. This has interested investigators trying to protect the engines of aircrafts and the blades of helicopters, which are abraded by blowing sand.

Yet when the sand whips by at speeds that would strip paint away from steel, the scorpion is able to scurry off without apparent damage. — The Economist

The African fat-tailed scorpion produces a powerful venom. It’s said to be one of the most dangerous scorpions and to cause several deaths ever year. Despite these scary facts, some people keep the animal as a pet. The animal feeds on invertebrates, lizards, and even rodents. Like the Peruvian giant centipede, it uses its venom to help it catch its prey.

The Japanese Giant Hornet

The Japanese giant hornet (Vespa mandarinia japonica) is also a scary animal, for two reasons. It’s the largest hornet and can give humans a painful sting. It’s also a voracious predator and eats large quantities of insects useful to humans, including honeybees. The animal is a subspecies of the Asian giant hornet,  or Vespa mandarinia.

The hornet’s body is about 1.8 inches long. Some hoax pictures have suggested that it’s much larger. The hornet model at the the PNE was impressively large and certainly lived up to the word “giant”. A sting from the real-life insect is said to be very painful. One sting is reportedly not harmful (unless a person is allergic to the venom), but multiple stings in quick succession may require medical attention.

The Japanese honeybee exhibits some interesting behaviour to protect its hives from the Japanese giant hornet. A mass of honeybees covers the body of the hornet that’s threatening them. This “bee ball” raises the body temperature of the insect, killing it. The European honeybees kept in Japan haven’t developed this protective technique and are susceptible to the hornet’s attack.

The Japanese giant hornet (or the Asian giant hornet, according to some reports) has been found in Europe, where it’s a threat to bee hives. The insect kills honeybees and feeds part of their bodies to its young.

Though I enjoyed looking at the arthropod models at the fair, I appreciated the fact that they stimulated me to think about the real animals most of all. Display boards with illustrations and facts about the animals added to the value of the models. Entertainment and education are a great combination.

References

• Peruvian giant centipede facts from the University of the West Indies
• The orchid mantis mystery from Science Friday
• Information about Adroctonus australis from the Norwegian University of Science and Technology
• An unusual scorpion exoskeleton from The Economist (introduction only)
• A defence against the Japanese giant hornet from the Honeybee Conservancy