Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Extreme weather decides distribution of insects

Extreme weather caused by climate change in the coming decades is likely to have profound implications for distributions of insects and other invertebrates. This is suggested by a new study of insects in tropical and temperate regions of Australia.

As climate change is progressing, the temperature of our planet increases. This is particularly important for the large group of animals that are cold-blooded (ectothermic), including insects. Their body temperature is ultimately determined by the ambient temperature, and the same therefore applies to the speed and efficiency of their vital biological processes.

Fruit flies have been the model for a study that has shown how climate change may affect insect distribution in the future. (Photo: Ary A. Hoffmann)

Periods of extreme heat and thus drought may be the cause of death for many insects. (Photo: COLOURBOX).

But is it changes in average temperature or frequency of extreme temperature conditions that have the greatest impact on species distribution? This was the questions that a group of Danish and Australian researchers decided to examine in a number of insect species.

Johannes Overgaard, Department of Bioscience, Aarhus University, Denmark, Michael R. Kearney and Ary A. Hoffmann, Melbourne University, Australia, recently published the results of these studies in the journal Global Change Biology. The results demonstrate that it is especially the extreme temperature events that define the distribution of both tropical and temperate species. Thus climate change affects ectotermic animals primarily because more periods of extreme weather are expected in the future.

Fruit flies were modelled

The researchers examined 10 fruit fly species of the genus Drosophila adapted to tropical and temperate regions of Australia. First they examined the temperatures for which the species can sustain growth and reproduction, and then they found the boundaries of tolerance for hot and cold temperatures.

“This is the first time ever where we have been able to compare the effects of extremes and changes in average conditions in a rigorous manner across a group of species”, mentions Ary Hoffmann.

Based on this knowledge and knowledge of the present distribution of the 10 species they then examined if distribution was correlated to the temperatures required for growth and reproduction or rather limited by their tolerance to extreme temperature conditions.

"The answer was unambiguous: it is the species' tolerance to very cold or hot days that define their present distribution," says Johannes Overgaard.

It is therefore the extreme weather events, such as heat waves or extremely cold conditions, which costs the insects their life, not an increase in average temperature.

Periods of extreme heat and thus drought may be the cause of death for many insects. (Photo: COLOURBOX).

Drastic changes in store

With this information in hand, the researchers could then model how distributions are expected to change if climate change continues for the next 100 years.

Most terrestrial animals experience temperature variation on both daily and seasonal time scale, and they are adapted to these conditions. Thus, for a species to maintain its existence under varying temperature conditions there are two simple conditions that must be met. Firstly, the temperature should occasionally be such that the species can grow and reproduce, and secondly, the temperature must never be so extreme that the population's survival is threatened.

In temperate climate for example, there are many species which are adapted to endure low temperatures in the winter, and then grow and reproduce in the summer. In warmer climates, the challenge may be just the opposite. Here, the species might endure high temperatures during the dry hot summer, while growth and reproduction mainly occurs during the mild and wet winter period.

The result was discouraging for all 10 species.

"Climate change will result in fewer cold days and nights, and thus allow species to move toward higher latitudes. However climate change also leads to a higher incidence to extremely hot days and our model therefore predicts that the distribution of these species will be reduced to less than half their present distribution"says Johannes Overgaard.

“In fact, our predictions are that some species would disappear entirely in the next few decades, even when they have a fairly wide distribution that currently covers hundreds of kilometers”, adds Ary Hoffmann.

"Although none of the 10 species studied are normally perceived as either harmful or beneficial organisms for human society, the results indicate that distribution of many insect species will be changed dramatically, and it will probably also apply to many of the species that have particular social or commercial importance ", ends Johannes Overgaard.

Christina Troelsen/Johannes Overgaard | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>