Professor Nigel Andrew

Right now, Australia is undertaking the world’s largest removal of invasive ants. The goal: eradicate fire ants (Solenopsis invicta).
These aggressive South American ants are named for the burning sensation of their sting. They pose risks to many native species – and to human health.
Fire ants have made it to Australia nine times, arriving in cargo ships. Eight times, authorities were able to stamp them out early. But an infestation detected in Brisbane suburb in 2001 has now spread across more than a million hectares of South East Queensland.
Authorities have used broadcast baiting to tackle fire ants, releasing pesticides over massive stretches of land since 2001. This approach works for small outbreaks. But my recent research suggests it may actually be making it easier for fire ants to spread.

Cabbage white butterflies – Pieris rapae – are one of the most common garden visitors across southern and eastern Australia. The butterfly looks elegant in white with black dots on its wings: females have a pair of black spots and males a single spot on each forewing. But their velvety green caterpillars are ravenous beasts on brassicas – the plant family that includes common vegetable crops such as cabbages, cauliflowers, broccoli, kale and bok choy.

The species was accidentally introduced into Melbourne in 1929 from Europe. Since then, cabbage whites have spread all over Australia, finally reaching Perth in 1943.

Because of their caterpillars’ addiction to eating brassicas, it is one of the most pervasive pests of any crop worldwide. Recent conditions have been favourable, resulting in large numbers of cabbage whites.

One female can lay up to 800 eggs. When they hatch, the caterpillars prefer densely planted hosts in moist, warm habitats. The caterpillars’ biomass can double each day, making them one of the fastest-growing cabbage-feeding caterpillars.