Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Why do insects stop ’breathing’?

15.02.2005


To avoid damage from too much oxygen, say researchers, challenging previous theories



The moth (Attacus atlas), above, and its pupa that Bradley and Hetz used for their experiments.



A new study investigating the respiratory system of insects may have solved a mystery that has intrigued physiologists for decades: why insects routinely stop breathing for minutes at a time.

Challenging previous theories, researchers at UC Irvine and Humboldt University propose that insects such as grasshoppers, moths, butterflies, some types of fruit flies, beetles and bugs close off their respiratory systems periodically to keep out excess oxygen, thus preventing damage to their tissues.


Timothy Bradley, professor of ecology and evolutionary biology at UCI, and Stefan Hetz, assistant professor of physiology at Humboldt University, Germany, report their findings in the Feb. 3 issue of Nature.

The insect respiratory system is designed to accommodate occasions when the insect is active. For example, a grasshopper is most active when it flies. When the grasshopper is inactive and resting, however, it continues to breathe in oxygen at the same high volume it uses while flying. The result is excess internal oxygen that can cause oxidative damage – the destruction of biomaterial due to excess oxygen – to tissues. To protect their bodies, insects like grasshoppers discontinue breathing.

“We propose that most insects stop breathing in order to lower their internal oxygen concentration to physiologically safe levels, and that they then substantially reduce gas exchange to maintain the oxygen at these safe values,” Bradley said. “This hypothesis explains the respiratory pattern of insects in different environments in ways that previous models can’t.”

Two previous models for explaining why insects punctuate their breathing with periods of closure are (1) such discontinuous breathing reduces water loss and (2) it enables insects to rid their bodies of carbon dioxide, respiration’s byproduct, when the insects are underground. As is true for miners, insects, while underground, are faced with high-carbon-dioxide and low-oxygen amounts, necessitating a better ventilation system. While oxygen is essential for their cells to produce energy, the removal of carbon dioxide from their bodies is equally important to prevent its toxic buildup in tissues.

“Even in our own case, our bodies have to supply oxygen to our tissues, but they must also keep out excess oxygen to prevent oxidative damage to the tissues. This damage is closely related to aging. Hence, perhaps, the many anti-oxidative creams flooding the market to combat aging. The concentration of oxygen in the air we breathe is toxic to us. Indeed, fruit flies, which have been studied closely for decades, die sooner from aging in a high-oxygen environment.”

Insects take in oxygen through spiracles – tubes connected to openings in their sides. In their study, the researchers inserted fine tubes into the spiracles of a moth to measure not only how much carbon dioxide the moth released but also the concentration of oxygen in its trachea, the series of tubes that carry air directly to cells for gas exchange. Using a respirometer (an instrument for measuring respiration that consists of a chamber with a flow-through air system), they monitored the moth’s breathing pattern. The chamber, which housed the moth being studied, was filled first with air that had been freed of carbon dioxide. Next, a device measured when and how much carbon dioxide originated from the insect.

Bradley explained that insects typically maintain 4-5 kilopascals of oxygen in their respiratory systems, 4-5 times lower than the normal oxygen concentration in the atmosphere. In a normal oxygen-concentration environment, the insect breathes for a period of time and releases a burst of carbon dioxide. It then closes its respiratory system, blocking off more intake of oxygen, to maintain the internal oxygen concentration at 4-5 kilopascals, the right oxygen concentration for its body. In a low-oxygen environment, the insect opens its respiratory system for longer periods of time; when it closes the system, it does so for only a very short time. In a stream of air with high oxygen on the other hand, the respiratory system opens briefly and then closes firmly for a long time. “In other words, insects are actively keeping oxygen out and doing it in a way that shows they know how to measure oxygen,” Bradley said. “Their behavior indicates they are regulating oxygen.”

Bradley and Hetz will next work on developing a comprehensive model of insect breathing. “We’d like to expand our present model to explain all aspects of insect breathing. And we’d like to examine insects that do not show this pattern – for example, desert beetles. While we have shown that insects monitor oxygen precisely, we do not know how that happens or which tissues and cells are involved. Once we’re equipped with a better knowledge of the insect breathing pattern it could shed light on when pesticides should be used to control insects – crucial for the agricultural industry.”

The research was funded by a grant to Bradley from the National Science Foundation.

About the University of California, Irvine: The University of California, Irvine is a top-ranked public university dedicated to research, scholarship and community service. Founded in 1965, UCI is among the fastest-growing University of California campuses, with more than 24,000 undergraduate and graduate students and about 1,400 faculty members. The second-largest employer in dynamic Orange County, UCI contributes an annual economic impact of $3 billion.

Iqbal Pittalwala | EurekAlert!
Further information:
http://www.uci.edu

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

Metallic nanoparticles will help to determine the percentage of volatile compounds

20.10.2017 | Materials Sciences

Shallow soils promote savannas in South America

20.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>