Australia a hot-spot for flora and fauna deception

17 December 2013

Researchers at Macquarie University and Auckland University have discovered that biological deception appears to be rampant in Australia, particularly as demonstrated by some of the better-known tricksters, such as cuckoos, orchids and spiders.

Deception in a biological sense refers to the manipulation of behaviour, and is usually accomplished by signals. A classic example of deception comes from bolas spiders, where female spiders mimic the pheromones of female moths, luring male moths into certain death.

Researcher Professor Marie Herberstein says Australia is renowned for its diverse and often curious fauna and flora, and now it seems that Australian plants and animals can’t be trusted either.

Cuckoos are well known for cheating their hosts into looking after the cuckoo brood. While they occur worldwide, Australia appears to have a higher than expected diversity of cuckoo species, and the Australian cuckoo hosts are less able to resist parasitism by cuckoos compared to other regions.

Sexually deceptive orchids mimic female wasps and lure male wasps into pseudocopulations during which the male inadvertently picks up the orchid’s pollen and delivers it to the next fraudulent orchid. This method of reproduction is remarkably common in Australian orchids, having evolved at least six times independently.

Even Australian crab spiders are more devious than their European or North American counterparts. Usually, crab spiders match their body colour to the flower they sit on, ambushing insects that are unable to detect their presence. In Australia however, these crab spiders are highly conspicuous by reflecting UV-light from their body surface. Their UV-rich colour acts as an attractive lure for pollinators who preferentially approach and even land on flowers occupied by these deceptive spiders.

The authors offer several explanations as to why deception, at least in these three examples, seems to be more common in Australia than elsewhere.

“The Australian dry climate and habitat fragmentation due to fire are likely to play a significant role in the evolution of deceptive strategies, especially in birds and orchids,” said Herberstein.

“The long evolutionary isolation of the continent, followed by more recent invasion from Asia, may have also exposed naïve natives to deceptive invaders that have subsequently radiated throughout the continent.

“Finally, the relatively young and non-conformist research culture in Australia may also encourage scientists to search out the obscure and cryptic, and certainly deception falls into that category.”

The authors argue that the combination of environmental, evolutionary and social contexts in Australia create the ‘perfect storm’ for deception.

“We expect that Australia harbors many more cases of deception and other biological curiosities and we encourage researchers to take advantage of the remarkable biology this continent offers.”

The full paper has been published online: Marie E. Herberstein, Heather J. Baldwin,  and Anne C. Gaskett. Deception down under: is Australia a hot spot for deception? Behavioral Ecology (2014) 25 (1): 12-16 first published online December 11, 2013doi:10.1093/beheco/art105

Filed under: Science & nature

Thomisus spectabilis crab spider. Credit: Ron Oldfield

Thomisus spectabilis crab spider. Credit: Ron Oldfield

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