Tuesday, September 28, 2010

Ecology: Locusts & Serotonin

Australian farmers having just recovered from one of the longest period of drought in recent memory are bracing themselves for another ecological effect of the return of the rainfall: locusts.

The drought caused a decline in the number of birds and other insects that normally feed on baby locusts. The rain also provided ideal breeding condition for locusts.

September being spring in Australia is when the locusts hatch and there are clear indications that the locusts will swarm.

Widespread high density hatching of eggs and the development of nymphal bands is expected during spring in the Central West, Far Southwest and Riverina regions of New South Wales, the Northwest and North Central regions of Victoria, and the Northeast and Murray Valley regions of South Australia. More localised high density hatchings are likely in Far West New South Wales, Southwest Queensland and the Far North and Southeast regions of South Australia.

Currently spraying with pesticides is the only means of control and they are not without problems.

“Some pesticides in use today are especially dangerous to wildlife. Two insecticides, carbofuran and diazinon, were involved in 55% of all bird incidents."

Earlier in 2009, scientists discovered that serotonin is the neurotransmitter that initiated the swarming behaviour in locusts:

Martin Enserink on 29 January 2009

Serotonin, the brain chemical involved in depression, anger, and a variety of other human behaviors, turns out to have another surprising role: It transforms desert locusts from solitary, innocuous bugs into swarming, voracious pests that can ravage orchards and fields in a matter of hours. The findings, published in tomorrow's issue of Science, could point the way to new locust-control methods that don't rely on insecticides.
Tom Fayle /National Geographic

Most of the time, the desert locust (Schistocerca gregaria) is a bland, greenish insect that lives an inconspicuous life, shunning other members of its species and flying only by night. But when their densities reach a certain threshold, locusts become gregarious: They seek out one another's company, start reproducing explosively, and eventually form massive swarms that can move thousands of kilometers beyond their usual habitats and create havoc of biblical proportions.

 The behavior changes are accompanied by a complete physical makeover, taking several generations, during which the insects first turn pink and eventually black and bright yellow.

.    Read the full article here>>>>.

It may be some time before we can make use of this new found knowledge!!!

Interesting facts from another website:     >>>> video

  • The 2010/11 locust season is predicted to be the worst outbreak in at least 30 years.
  • A swarm covering one kilometre can eat up to 10 tonnes of vegetation per day.
  • If 100 hectares of locust bands are not effectively controlled they may develop into 1,000 hectares of adult swarms.
  • Past campaigns have shown that for every $1,000 spent controlling locusts, at least $20,000 worth of crops and pastures have been saved.
  • Australian plague locusts generally mature within two weeks of becoming adult.
  • Females can commence egg laying 4-7 days after maturing.
  • In summer, eggs can hatch within 14–16 days.
  • Female locusts lay eggs in batches, called pods, in the soil and each pod can contain up to 60 eggs.
  • Locust “bands” can contain up to 15,000 hoppers per square metre at the front of the band.
  • Swarms generally fly within 15 m of the ground and frequently at less than 3m and often appear to roll across the countryside.
  • Swarms can infest areas up to 50 km2.
  • Locusts can migrate up to 600 km or more in a single night.
  • People in several countries eat locusts. Locusts are rich in protein and can be stir-fried, roasted or boiled.
  • A swarm of locusts, covering 1 kilometre (km)2, could contain anything from 4 million to over 50 million individual locusts.

1 comment:

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