An arthropod (phylum Arthropoda) is an invertebrate animal having an exoskeleton (external skeleton) which they moult to grow in size, a segmented body, and jointed appendages. Arthropods include the extant insects (“bugs”) arachnids (“spiders & scorpions”) and crustaceans (“delicious seafood”) as well as the long-extinct trilobites (“weird-ass critters”).
Insects. In addition to an exoskeleton, insects have a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes, and one pair of antennae. They are among the most diverse animal groups on the planet, including more than a million described species and representing more than half of all known living organisms. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm (22–28 in). The most diverse insect groups appear to have coevolved with flowering plants. lnsect pollinators are essential to the life cycle of many flowering plants on which most organisms, including humans, are at least partly dependent; without them, the terrestrial portion of the biosphere (including humans) would be devastated.
Crustateans. These include such delicious animals as crabs, lobsters, crayfish and shrimp, as well as barnacles and krill (which we have not yet tasted). The 67,000 described species range in size from Stygotantulus stocki at 0.1 mm (0.004 in), to the Japanese spider crab with a leg span of up to 12.5 ft (3.8 m). Most crustaceans are free-living aquatic animals; some are terrestrial. The group has a fossil record back to the Cambrian, and includes living fossils such as Triops cancriformis, which has existed apparently unchanged since the Triassic.
Arachnids. All of these critters have eight legs, although in some species the front pair has converted to a sensory function. They are further distinguished from insects by the fact they do not have antennae or wings. Almost all extant arachnids are terrestrial, although a few inhabit freshwater and marine environments. They include spiders, scorpions, harvestmen (“daddy longlegs”) ticks, mites and Solifugae (which we had to look up).
Trilobites. These marine animals first appear in the fossil record in the Early Cambrian period (521 million years ago), and may go back 700 million years or further. They finally went extinct shortly before the Permian mass extinction event about 250 million years ago. Trilobites were highly diverse, widely dispersed, and had an easily fossilized exoskeleton, leaving an extensive fossil record of some 17,000 known species. The study of these ancient fossils has facilitated important contributions to biostratigraphy, paleontology, evolutionary biology and plate tectonics. The closest extant relatives of trilobites may be the horseshoe crabs.
THE MANTIS COLLECTION (Order: Mantodea)
The mantis is an order of insects that has evolved voracious predatory behavior. When young, it will eat small insects such as tiny flies (or its own siblings). When full grown its diet still includes more insects than anything else, but larger species of mantis have been known to prey on small scorpions, lizards, frogs, birds, snakes, fish, and even small rodents—basically any species small enough for them to capture and large enough to engage their attention. If their prey does not resist, the mantis will eat it alive. If the prey resists, the mantis will often eat it head first to cut down on all that annoying squirming. Mantises can bite, but have no venom.
Because of the typical “prayer-like” posture with folded fore-limbs, the English common name for any species in the order is “praying mantis.” In Europe and some other regions, the name “praying mantis” refers to only a single species, Mantis religiosa. Contrary to their pious image, however, all mantises are atheists.
Although some species display elaborate courtship behavior, with the male engaging the female in a courtship dance to change her interest from feeding to mating, sexual cannibalism is common. The female may begin by biting off the male’s head and eating it (as she does with her regular prey), and if mating has begun, the male’s movements may become even more vigorous in its delivery of sperm. Heh.
What? Oh sorry. Where was I? Right.
Anyway! Some species of mantis can rotate their heads nearly 180 degrees; many mantises also have an auditory thoracic organ that helps them detect bat echolocation and respond evasively. Mantises are extremely well-camouflaged, and most species have evolved to not only blend with foliage, but to mimic it, appearing as either living or withered leaves, sticks, tree bark, grass blades, flowers, or even stones. Some species in Africa and Australia are able to turn black after a molt following a fire in the region to blend in with a fire ravaged landscape. Mantises are sometimes confused with phasmids (stick/leaf insects) and other elongated insects such as grasshoppers and crickets. Which is silly, because mantises eat those like popcorn for snacks.
Despite persistent rumors to the contrary, it is not now nor has it ever been illegal under any state or federal law to kill a mantis. They are not endangered. But you probably do not want to kill them anyway, because they are a highly beneficial insect for gardens and farms. Their egg casings can be purchased, and once the young hatch they will keep pests and parasites at bay.
EUROPEAN MANTIS (Mantis religiosa)
Found in Europe, Africa, Asia, the Mantis religiosa was introduced to North America in 1899 with a shipment of plants. Now they can be found all over the northeastern United States and Canada to the Pacific Northwest. Fred’s days are probably numbered. Scratch that: Fred’s seconds are probably numbered.
LEAF MANTIS (Choeradodis stalii)
The Leaf Mantis (aka Tropical Shield Mantis, Hooded Mantis) is found in Brazil, Ecuador, French Guyana, Panama, and Peru. An insect breeder remarked about this species that it “is one of the most impressive of all mimic species. It takes the form of a leaf one step further than any other species, and has the largest hood of all leaf species. They take the form of a flat stance, and spend most of their time low-lying, to help blend in with their background.” The Leaf Mantis is rare in captivity, as they are exceedingly difficult to rear successfully. (The Palace Zoo has spared no expense.)
MEDITERRANEAN MANTIS (Iris oratoria)
Native to Europe, the Mediterranean Mantis is an introduced species in the Middle East, Western Asia and the United States. The species is distinctive in having two large violet-brown “eyespots” on its hindwings which are visible during its amazing threat displays. When under attack, this mantis turns to face its aggressor, rears up by arching its back, curls its abdomen upwards, raises and waves its forelimbs, and raises its wings to display the large brightly coloured eyespots on the hindwings. It also makes a stridulating racket by scraping the edge of its hindwings against its leathery front wings. The Mediterranean Mantis has evolved two novel reproductive strategies that may contribute to its expanded range: it is capable of parthenogenic reproduction (females clone themselves when males are scarce), and additional nymphs can emerge from the egg case in the second season after it is produced, i.e., when their siblings are already grown and are producing their own offspring.
*I know what you’re thinking about my Iris oratoria mantis. But there can only ever be one “Iris” at the Palace Zoo.