Dennis brought along some brilliant photos he has taken over the years, just a small selection of the ones that have fascinated him the most. With each insect he described, Dennis projected up a larger than life closeup picture to show off the best features. He is very passionate and moved from one to the other very quickly, sharing snippets of information as he went. I have done the best I can to string his information into a report for everyone who missed his brilliant presentation.
Insects occur on every continent in the world, including Antarctica!
Current estimates suggest there are 70,000 insect species in Australia, 20-30 million worldwide. But most are yet to be classified. Of this total less than 1% are pests. Their bad reputation comes because most people only notice them when they are a problem.
3/4 of all species on earth are insects. They have been around for longer than most other species.
Insects are incredibly important to the environment. They are responsible for pollination, seed dispersal, dung burial, recycling and even as food to plants.
If vertebrates disappeared overnight the world would continue on. If insects disappear the ecosystem collapse. They are of incredible importance to our everyday lives!
Meganeura monyi, the forerunner of dragonfly had a wingspan of nearly a metre! This was in the Carboniferous era, an oxygen rich time in which it was far easier to survive with a more primitive respiratory system without lung structures. In fact it was the presence of a diverse range of insects that drove the diversification of flowering plants. They fall into 6 major categories
- Orthoptera– grasshoppers katydids locusts. They appeared 300 million years ago. A local example is the Raspy Cricket in the Grampians. It produces silk from its mouth to join leaves, has long antenna and curved ovipositor as a nymph. But after maturity does not have the long ovipositor.
- Coleoptera– beetles, these were the first important pollinators. Approximately 30,000 species occur in Australia. 1/3 of these are weevils. Botany Bay weevil is present in the Grampians and endemic to large areas across the rest of Australia. It is so named for the area where it was first identified. Not surprising as it was the first place European biologists saw of Australia.
- Lepidoptera– moths and butterflies developed sucking mouthparts and became nectar and pollen feeders. Approximately 20,000 moths (450 of these are butterflies) in Australia. Butterflies fold their wings back behind them, moths lay them flat along their body like a carapace. The Mistletoe moth only feeds on mistletoe, the Crexa moth only feeds on cherry Ballart trees. If these plants are removed from the environment, so are the insects. Is it possible this relationship works the other way? It’s not yet known as there are so many to study, and funding goes towards looking at pest insects mostly.
- Neuroptera are the Lacewings. Antlion lacewings myrmeleontidae, create a cone shaped trap in the ground to capture their prey, usually ants. They flick sand at the ants on the side of the trap so they fall down into the centre where they can be eaten. This flick is one of the fastest actions in the natural world.
- Isoptera includes termites and ants/wasps
- termites deadwood feeders/recyclers 350 species replace large herbivores in Australia, breaking down plant material. They also replace earthworms in dry northern climates. Termites fly, but discard wings when they land. Some termite soldiers have a “glue gun head” to squirt at ants that enter the mound.
- Ants evolved 100 million years ago, with an incredibly complex social structure to their colony. There are 3,000 species identified in Australia. But it could be double that. The workers are sterile females, the highest numbers within the colony. Then there are the breeding male drones, and the smallest number are fertile queens that do all the reproduction. Nuptial flights take place where a complete new colony moves all at once. Males are twice as big as female workers, the queens are twice as big again. Workers don’t fly, but they do get carried sometimes. Ants use a chemical based communication, when they are agitated or injured you can sometimes smell this yourself. A Formic acid smell. They are the first colonisers after bushfires, and a great indicator of environment health. Some ants eat insects, some are herbivores, and some feed on sugars produced by other insects, so they farm them but do not kill them, just consuming their discharge.
- Myrmecia species are the bull ants. Scavengers but will also kill other organisms to eat.
- Funnel ants build the funnel shaped sand castles on entrance of hole, to prevent water entry.
- Inqualine ants live in termite nests and cooperate to gain the benefit of the shelter provided by the mound in a very harsh hot dry climate.
- The Flower Wasps are the ultimate romantic. Males have wings but females don’t. (However the ladies do have a bad sting.) They burrow under ground to lay eggs in living beetle larvae. Males are attracted by the female pheromone and they will carry a female to a flower to mate and gorge on nectar. Instead of taking her flowers, they carry her to the florist! But they are competing with the Scorpion fly, which have incredibly dextrous legs. The male will feed other flies to the female during mating!
- Diamma bicolour, the Blue Ant is actually a wasp. The female sting is intensely painful. They are parasitic on mole crickets, males are too small to carry the female, so they mate on the ground.
- A Spider Hunting Wasp will grip the fangs of a huntsman, hold on tight, and inject a sting to paralyse the spider. It then lays eggs in the living spider in her nest, as a natural nursery with food built in! They are bigger and stronger than huntsman.
- Cuckoo wasps have an armour plated schlerotised carapace. They curl up as a defence from the wasps they invade to lay eggs in their nests. Th Cuckoo wasp larvae hatch first and eat the other wasp larvae. The adults are then providing food to raise the cuckoo wasp and not realising it!
- Diptera are Flies.
- Eucalyptus sawfly species are also known as spitfires. Pergagrapta polita is the common spitfire. The name comes from their defence of vomiting concentrated eucalyptus oil. If this gets into your eyes it creates a strong burning sensation.
- Some flies parasitic on spiders, eat them from inside out. Mantispidae, the mantis fly have parasitic larvae that eat spiders. Bladder flies in Grampians do this
- Chrysopidae, larvae have a jaw looking device that is actually straws for sucking the fluids from their insect prey. They collect the bodies of their food on their back, along with lichen as camouflage.
Aphids are introduced to Australia. This could be why they have become such a garden pest.
There are even some insects who’s larvae produce potassium cyanide as a defence mechanism.