Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Australian fire beetle avoids the heat - Its infrared organs warn the insect of hot surfaces

15.02.2018

The Australian jewel beetle Merimna atrata has several heat sensors. Originally it was thought that it uses them to detect forest fires: The insect lays its eggs in the wood of burned eucalyptus trees. Researchers at the University of Bonn were finally able to refute this hypothesis. Instead, the beetle appears to need its heat sensors for a different purpose: to not burn its feet on landing. The study has now been published in the journal PLOS ONE.

The Australian fire beetle is attracted to freshly burnt wood. Experts also call this pyrophilia (“love of fire”). This behavior is not very common in insects. Merimna atrata however has a good reason for this: The dead wood provides plenty of food for the larvae of the beetle, so it uses the wood for oviposition.


The fire beetle is fixed in flight, but still able to turn left and right. Despite of good eyesight, beetles did not change direction when exposed to images of forest fire.

© Helmut Schmitz / University of Bonn

But how does Merimna find a freshly burned area? For some time it has been known that the fire beetle has heat sensors with which it can detect infrared radiation. In a sense, it “sees” hot places in its environment against a cooler background. It was originally believed that the insects use this ability to detect forest fires.

“However, the IR organs in Merimna atrata are relatively insensitive”, Dr. Helmut Schmitz emphasizes. Schmitz is a lecturer at the Institute of Zoology at the University of Bonn; he investigates thermo and infrared reception in the black insects for nearly two decades. “This actually contradicts the assumption that the IR organs enable the beetle to detect fires from a greater distance.”

Beetles stuck with glue

Together with his colleagues, Schmitz has now been able to demonstrate for the first time that these doubts are justified. The scientists designed an ingenious experiment for this purpose. Put simply, they stuck the beetles with their backs to the end of a pin and used this to hang them up. This left the experimental animals with the ability to fly continuously, but without moving forward. “More importantly: They were able to navigate in any direction, i.e. turning right or left”, emphasizes Schmitz.

Then the scientists stimulated the flying beetles with weak infrared radiation from the side. The beetles changed their flight direction in response, but always away from the source and never towards it.

“Merimna’s IR organs are located on both sides of its abdomen; incidentally, this is unique in the animal kingdom”, explains Schmitz. “When we occluded the IR receptors with aluminum foil, the animals no longer reacted to the radiation, but always carried on flying straight ahead. As soon as we removed the foil they displayed their original behavior again.” This observation suggests another use of the heat sensors: “Presumably they help the fire beetles avoid hot spots when approaching an oviposition site such as a freshly burnt branch; these hot spots are not visible with the naked eye to humans and animals during the day,” says Schmitz.

How the animals detect forest fires remains unclear. Even visual stimuli seem to play no role in fire detection, despite Merimna atrata having good eyesight. The researchers tested this hypothesis by showing the beetles slides of large clouds of smoke rising above a forest area. But the insects were completely unimpressed: They never changed their flight direction.

Following the nose

“We therefore assume that Merimna atrata gets its information about an ongoing fire from the smell of smoke”, concludes Helmut Schmitz. This is also important for another reason: Odors can tell you exactly what is actually burning. In contrast, this information cannot be inferred from the heat development or the appearance of a smoke plume. Merimna is very picky: It only lays its eggs in burnt eucalyptus wood and avoids other trees. If the insect was to rely on its IR sense, it would risk being lured into the wrong kind of fires.

Something quite different can be seen with a close European relative; the fire beetles of the genus Melanophila: Their larvae develop in a variety of trees. Heat perception would be quite worthwhile for them. In fact, Melanophila also has infrared sensors, but they are completely different. They can presumably detect infrared radiation even from a long distance: According to measurements and theoretical calculations, Melanophila heat sensors are at least 500 times more sensitive than those of Merimna atrata.

Publication: Marcel Hinz, Adrian Klein, Anke Schmitz and Helmut Schmitz: The impact of infrared radiation in flight control in the Australian “firebeetle” Merimna atrata; PLOS ONE; DOI: 10.1371/journal.pone.0192865

Contact:
PD Dr. Helmut Schmitz
Institute of Zoology at the University of Bonn
Telephone: 0228/73 20 71
Email: h.schmitz@uni-bonn.de

Dr. Andreas Archut | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-bonn.de/

Further reports about: beetle forest fires hot spots infrared radiation insect insects larvae

More articles from Life Sciences:

nachricht Elusive compounds of greenhouse gas isolated by Warwick chemists
18.09.2019 | University of Warwick

nachricht Study gives clues to the origin of Huntington's disease, and a new way to find drugs
18.09.2019 | Rockefeller University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Happy hour for time-resolved crystallography

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.

The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.

Im Focus: Modular OLED light strips

At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.

Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...

Im Focus: Tomorrow´s coolants of choice

Scientists assess the potential of magnetic-cooling materials

Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....

Im Focus: The working of a molecular string phone

Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Potsdam (both in Germany) and the University of Toronto (Canada) have pieced together a detailed time-lapse movie revealing all the major steps during the catalytic cycle of an enzyme. Surprisingly, the communication between the protein units is accomplished via a water-network akin to a string telephone. This communication is aligned with a ‘breathing’ motion, that is the expansion and contraction of the protein.

This time-lapse sequence of structures reveals dynamic motions as a fundamental element in the molecular foundations of biology.

Im Focus: Milestones on the Way to the Nuclear Clock

Two research teams have succeeded simultaneously in measuring the long-sought Thorium nuclear transition, which enables extremely precise nuclear clocks. TU Wien (Vienna) is part of both teams.

If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Society 5.0: putting humans at the heart of digitalisation

10.09.2019 | Event News

Interspeech 2019 conference: Alexa and Siri in Graz

04.09.2019 | Event News

AI for Laser Technology Conference: optimizing the use of lasers with artificial intelligence

29.08.2019 | Event News

 
Latest News

Stroke patients relearning how to walk with peculiar shoe

18.09.2019 | Innovative Products

Statistical inference to mimic the operating manner of highly-experienced crystallographer

18.09.2019 | Physics and Astronomy

Scientists' design discovery doubles conductivity of indium oxide transparent coatings

18.09.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>