Revealed: bushfires and low rainfall caused biting insects to swarm

This article is over 7 months old A new study has found that bushfires and lower-than-normal rainfall were key factors in the rise of large insect populations over the past 40 years. D. parathion,…

Revealed: bushfires and low rainfall caused biting insects to swarm

This article is over 7 months old

A new study has found that bushfires and lower-than-normal rainfall were key factors in the rise of large insect populations over the past 40 years.

D. parathion, also known as the white tick, normally inhabits tropical areas.

Under poor conditions, ticks spread at a rapid rate by luring unwitting animals into their burrows with tick serum – technically a deodorant – but now the diptheria mosquito, which feeds on the tick, seems to be a go-to predator in the north-west of the country.

The study of invasive tick populations in north-west Australia conducted by the CSIRO, showed bushfires and late summer rainfall led to the highest average year-on-year tick density change between 1975 and 2015.

Adrian Bennett, a senior research scientist, said depleting the stock of the vegetation feeding the red-winged blackbird, as well as kelp forests feeding other insects, made them more inclined to be ready for a tick.

“Ticks don’t need ideal conditions to feed on red-winged blackbirds and kelp forests,” he said.

Moose ticks are spread by stray red-winged blackbirds. Photograph: David Phillips/CSIRO

The other major factor came in what the tick likes to call “extreme summer” – when it gets a number of close “windbursts” and has more nutrients to pick from.

Bennett said the ticks spread from the south and east of the north-west, from the Kimberley region further south to Rokeby and the surrounding area in the north, to the north-west Pilbara region to the south.

“It looks like bushfires, because there were fewer late summer storms [in those regions], and one of the things that tick-borrowers like was the feed of the red-winged blackbird and kelp forests – both of those are wiped out by highly extended and severe heatwaves,” he said.

Bennett’s findings could have an impact on some of the state’s largest tourism industries – bushwalking and the asparagus industry – as ticks would have less food supply to latch on to and expand to.

Tick bites can trigger fevers, jaundice and meningitis. A marked reduction in the amount of raw, uncooked asparagus available in early September would have an impact on the northern states’ asparagus industry.

Hopes of finding an effective treatment for tick infections for humans and animals were dashed last year after a trial showed no positive signs of efficacy.

In Australia there are about 20,000 tick bites, or two out of every 1000 people, each year.

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