the dragon with A jet engine bum
Which bug is the greatest superhero?
Dragonfly expert Jessica Ware answers
Three people, one big question. In this edition: superbugs
Jessica Ware’s 3-minute noodles
“These insects have a great origin story. Dragonflies and damselflies live in freshwater as juveniles, breathing underwater with gills, and then they emerge and spend their adult lives on land – a dramatic transition! But they don’t live long as adults – the majority of their lives are spent as juveniles in the water. Some species spend four or five years in the water as juveniles while others only live there for four to six weeks. The adult stage is generally three months long regardless of the species.
Beat this – jet engine bums! Juvenile dragonflies breathe out of their bums and can suck water in then expel it for jet propulsion. Hard to imagine, but true! They have rectal gills, and water is brought in for them to get oxygen to breathe. But, when startled, or when hunting, they can let a larger volume of water into their rectal cavity and then expel it in a rapid swoosh. That thrust can be used to propel them when lunging to catch prey or when swimming away from a predator.
Dragonflies are trend setters. Only a few animals fly (birds, bats, pterosaurs, insects) and of those that do, insects did it first. Dragonflies and damselflies are remarkable insects. They form the order Odonata, and are the earliest branch in the winged insect section of the tree of life. As such, they are neat to study as their flight style is slightly different from other insects, and that gives us insight into the evolution of early flying styles.
Super sight, fight and flight. These insects use interception style flight, where they cut off their prey at the pass, rather than flying to where they first spotted their meal, which is a neat style of hunting. Dragonflies are predators, and as adults they eat flies, butterflies, whatever they can catch really – and they hunt on the wing. As juveniles, they eat insect larvae and also small fish and tadpoles. Their eyes see several colours, and they’re highly visual predators. They’re fast too, some migrating thousands of kilometres. They are voracious predators and they eat the things we can’t stand, like mosquitoes and biting flies, plus they are terrific food themselves as prey for birds, frogs, fish and other animals. They are harmless to humans – they don’t bite people, they do not sting, and they are not aggressive.
Some species can even change their colour, either to blend in with their surroundings or to regulate their temperature. They have colour pigment that can migrate in their cells, so after mating, for example in Argia apicalis, the males can turn from bright pale blue to deep purple. This might allow them to absorb heat or to be less visible to their predators – namely frogs, fish and birds.
They’re masters of dealing with hostile conditions. There are over 6,500 species, and between them they live in a wide range of habitats. Some, like Erythrodiplax bernice, survive living in brackish or salty water while Somatochlora sahlbergi live in the Arctic Circle and can remain frozen for periods of time as juveniles. Others, like Pantala flavescens have been found in extremely arid conditions in the Namibian desert, while Pachydiplax longipennis have been found in urban cities, even laying eggs in swimming pools. There are around the same number of species of dragonflies and damselflies as there are mammals, so it’s not surprising to see them in different habitats – just as you wouldn’t expect polar bears, jungle cats and kangaroos to live side-by-side. I am always amazed by how much variation there is among these species. There is not one single “dragonfly” way of life, each species has a slight variation in their traits and behaviours.
Dragonflies are climate canaries, as they usually move to new areas when they become hospitable, and leave areas when conditions are not as favourable. Not all species can do this; some might instead go locally extinct.
Ready to hear about their unique reproductive strategies? Buckle up. Females mate multiple times and can store sperm in their bodies in special sperm storage organs. Males have evolved a secondary reproductive apparatus that scrapes out the previous male’s sperm in what’s presumably an attempt to ensure paternity. They have been around a lot longer than us – likely over 250 million years – so they hold a lot of history in their lineage!
The Dragonfly sounds like a legitimate superhero name. If Hollywood put this character on screen, they’d be a goodie, for sure! They’d be a super-fast hero, with laser-sighted vision, and who could catch just about any bad guy – but they would eat the bad guy immediately, likely while flying, and so there would be no day in court, I guess.
We need dragonflies. Without them, flies would not have this predator to suppress their populations, so it wouldn’t be much fun. Plus, birds and other animals that rely on dragonflies for food would lack that diet staple and so they would likely suffer.
What’s so good about this?
We need to start seeing bugs as superheroes, and that’s exactly what these three insect-lovers are doing. If we get to understand the brilliant work bugs are doing to keep our planet healthy, perhaps we’ll be better equipped to help them thrive.
Are you curious about the amazing superpowers of the dragonfly – and other bugs? You can find out more from the World Dragonfly Association and the Dragonfly Society of the Americas. Follow @JessicaLWareLab and @jessicaleeware42.
Meet the writer
When she’s not pretending to be a beaver holding back the rivers, Katie Dancey-Downs is a freelance writer and journalist with a passion for human stories, nature and culture. She’s travelled the world to report on issues such as vegan activism in Toronto, regenerative farming in India, and the destruction of Sacred Natural Sites in Kenya. She can usually be found with her head in a book, stomping through the forest, or wishing she looked cool on a surfboard. Follow @Katie_Dancey.