Katydids belong to the order of Orthopterans and number more than 6,400 species around the world, 17 of them in Québec! They have powerful hindlegs that they use for jumping, and very long antennae – which incidentally is what distinguishes them from locusts and crickets, whose antennae are short. With their camouflage they look a lot like leaves, making them very difficult to observe in nature.
A first at the Insectarium: exotic katydids!
Exotic katydids are very little known to science. There’s almost no data on the five species that we’re rearing at the moment, all of them hailing from Central America, South America or Asia. As a result, if we want to know more about them we really have to observe them ourselves all the way through their development.
Everything begins with the receipt of a package, sometimes from the other side of the world. It contains a small well-wrapped box in which mysterious little eggs are protectively draped in a piece of cotton. From that moment on, there’s nothing but discovery! Katydid eggs look like minuscule grains of rice, and you have to be careful with them. The first thing you do is some research into the species, and quickly you become aware that information is extremely rare, if not non-existent. So you ask yourself: how long do the eggs take to hatch? Is a katydid a herbivore or a carnivore? How long does it take the species to reach adulthood?
The development of katydids
After a number of weeks, or even months, the eggs hatch. The juveniles are less than one centimeter in size, but their antennae can be as much as six centimeters long! After the hatching, we begin to test different types of food. If the species is carnivorous, it’s simple enough, because it’s just a question of giving it proteins (flakes of fish feed, for example). But if it’s herbivorous, what plant does it feed on? We research, and we test some more. We leave each other notes on the vivariums: this species “likes zucchini and apple,” that species “loves arums.”
The type of the katydids’ food will determine their behavior and the way in which they should be reared. Most katydids can be raised in a group, but for carnivorous katydids, they very often have to be reared individually to avoid cannibalism!
As the weeks go by, katydids are going to molt a number of times, and in the course of their development wings appear and grow with each molt. They change color and shape, and their evolution is wonderful to see. After a few months, we know that our work has borne fruit when the first adults appear.
A curious species: the unicorn katydid
The unicorn katydid, Copiphora cornuta, is a native of South America. No information existed about it. Two adults emerged just recently in our rearing center, the other individuals being still at the juvenile stage. In the course of the molts, a yellow horn appeared on top of the heads of these beautiful green seven-centimeter katydids, which can also display other bright colors like pink and turquoise. We don’t know what the evolutionary role of that horn is – whether it serves as a means of defense, for instance – but it lends the katydid so much character, in addition to piquing our curiosity. A true marvel!