As Sydney warms, tropical insects move in


Insects such as the crow butterfly and snake mantis have extended far to the south of their traditional Queensland habitat and scientists believe the gradual warming of temperate Sydney is the cause, reported The Daily Telegraph (13 November 2006 p12).

Former tourist now resident: Australian Museum naturalist Martyn Robinson said the crow or oleander butterfly was once only found in Sydney in the hot summer months and then only if blown down by northerly winds. It is now breeding and living year-round in Sydney. "It used to be news if people found them breeding in Sydney but now it happens all the time," Dr Robinson said.

Telltale signs: Following the hottest October on record and predictions of above-average temperatures for spring and summer, other signs of a warmer, drier Sydney have emerged:

Cicadas, which normally hatch in November, were early this year. Entomologist David Britton said cicadas had been out since October;

Jacaranda trees have bloomed with much more vibrant and abundant flowers; and

• Tropical bee hawk moths, snake mantises and plumbago blue butterflies are being noted in increased numbers.

Birds doing it, why not insects? Macquarie University ecologist Associate Prolessor Lesley Hughes said the permanent presence of tropical insects in Sydney was no surprise. “We do have some reasonable data for birds moving south [from tropical areas] and it’s reasonable for insects to be doing the same thing," she said.

Starting early: Cicadas usually arrive in Sydney in November; however, Australian Museum entomology collection manager David Britton said the insects had been here for weeks.

Beautiful cicada

The Daily Telegraph, 13/11/2006, p.12

Source: Erisk Net  

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