One of Kakadu’s iconic species – the brightly-coloured Leichhardts grasshopper is showing healthy populations across a number of survey sites. In 2012 a large, hot bushfire occurred and we expected to see less alyurr the following year. However, in January 2014 there was a huge increase in numbers at one of the regularly surveyed sites – from 13 to 800 individuals.
Such a rapid increase has never been recorded in Kakadu so this is a really interesting occurrence. As there weren’t enough females to have laid that many eggs, it suggests that, unlike most tropical grasshoppers, alyurr eggs may be viable for more than one year. This is exciting news because it means the population may have a better chance of survival in the case of an uncontrolled fire or other event.
Twelve months on, the population at the site had risen again. We think this is because they were eating a plant called Dampiera conospermoides which is completely unrelated to the Pityrodia plants they normally eat. This also seems to be the first record of alyurr using this plant as a major food source.
Annual monitoring of this iconic grasshopper means we can continue learning more about the species, and hopefully help it to flourish.
Dr Dan Wilkins, Kakadu National Park