What are mole crickets and what do they look like?
Mole crickets are nocturnal insects related to locusts, grasshoppers and other crickets. Their stocky front legs and outward-facing claws resemble those of a mole and are used for burrowing into and tunnelling through soil. Most crickets use their long back legs to jump. Mole crickets spend a lot of time underground so their back legs are shorter. They are used to push soil aside as they dig.
Mole crickets have a brown segmented body. The first segment is enlarged and covers the head to protect it while burrowing. They have two antennae and a soft abdomen with two long cerci – feelers – attached at the end. Both males and females have a pair of wings but it is mostly the females who use them to fly. Mole crickets are a medium sized insect growing up to four centimetres in length.
The Gryllotalpa pluvialis species is native to Australia.
Where do mole crickets live?
Mole crickets live on every continent except Antarctica. Australia's native species lives mostly on the east coast.
Natural habitats include woodlands and damp, rich soils in vegetated areas. Managed habitats include gardens, parklands, well-watered lawns like golf courses, vegetable gardens and compost heaps. Because they disturb lawn and feed on underground grass roots they are considered a pest in many countries.
They dig a maze of tunnels underground where they spend most of their lives feeding, breeding and avoiding predators. Mounds of soil indicate where the tunnel entrances can be found.
What do mole crickets eat?
Mole crickets can be herbivores, carnivores or omnivores. Herbivorous species feed only on the roots of vegetation in their underground tunnels. Carnivorous species feed on worms, grubs, insects and other invertebrates found in the soil. Omnivorous species will eat both.
What eats mole crickets?
Mole crickets are eaten by lizards, birds, toads, beetles and spiders.
Mole crickets are also prey for the blue 'ant' which is actually an Australian parasitic wasp. Female blue ants paralyse the cricket and lay eggs on their bodies. The crickets become an instant food source for the newly hatched wasps.
How are mole crickets adapted to their environment?
Mole crickets have strong, powerful front legs with outward facing claws that are well-adapted for digging underground homes to live in. Their hind legs have no use for jumping as they spend most of their lives underground. Instead they are used for pushing soil out the way as they tunnel and dig. The leg spines assist in digging and plowing through the ground.
The first segment of their bodies is adapted to protect their heads while burrowing, and to assist in pushing through different types of earth.
Adapting to an underground habitat provides some protection from predators especially as there are many tunnels to hide in and many exits to escape from.
If disturbed, mole crickets can squirt a foul smelling liquid from their back end as a defence mechanism.
How do mole crickets reproduce?
Mole crickets mate underground. Males will face inwards and call into the funnel-like entrance to attract females. Facing inwards amplifies their call. Their call is created by rubbing the wings together. Females can distinguish between a moist underground home or a dry one just by listening to the type of sound being produced. Damp soil chambers win the females!
After mating, females will dig a golfball-sized chamber in which to lay a clutch of eggs. The number of eggs laid depends on the species. Most females belonging to the mole cricket species will guard the eggs until hatched and care for the hatchlings.
There are three stages in the life cycle of mole crickets - eggs, nymphs and adults. Nymphs hatch from the eggs after a few weeks. They look like adults but are white, much smaller and have smaller wings. They moult many times as they grow and mature into adults.
