Nav: Home

New study changes our view on flying insects

September 29, 2017

WATCH: A tobacco hawkmoth flies in a wind tunnel (https://www.youtube.com/watch?v=4Sgqb8wnQGA)

For the first time, researchers are able to prove that there is an optimal speed for certain insects when they fly. At this speed, they are the most efficient and consume the least amount of energy. Corresponding phenomena have previously been demonstrated in birds, but never among insects.

Previous studies of bumblebees have shown that they consume as much energy in forward flight as when they hover, i.e. remain still in the air. New findings from Lund University in Sweden show that this does not apply to all insects.

Biologist Kajsa Warfvinge, together with her colleagues at Lund University, has studied the large moths known as tobacco hawkmoths or Manduca sexta. The results show that these moths, like birds, consume different amounts of energy depending on their flight speed. Flying really slowly or really fast requires the most effort.

The discovery may help other researchers who study how insects migrate from one environment to another.

"I imagine that our results could be used indirectly to predict how well different species respond to changing temperatures in view of global warming. By knowing how much energy is needed to fly at different speeds, we can calculate how far and fast the animals can travel given a certain amount of energy", says Kajsa Warfvinge.

The experiments were performed in a wind tunnel. Using a specially developed technique known as tomographic PIV, the researchers can record the way the air moves in three dimensions when the tobacco hawkmoth flaps its wings. The vortices left in the air can be seen as the insect's aerodynamic footprint. The vortex strength reflects the amount of kinetic energy added by the insect, which in itself is a measurement of how exerting it is to fly at different speeds.

The results show that classic aviation theory can be applied also to tobacco hawkmoths; that is, it takes a lot of energy to fly slowly (one metre per second), since it is difficult to create lift at these speeds. The same applies when insects fly fast (four metres per second), but here it is the air resistance that makes the flight less efficient from an energy perspective.

"We demonstrate that moths have the same U-shaped relationship between speed and power as birds and aircrafts do. Flying slowly or fast is exhausting and requires more energy. You could say that flying at a moderate speed is optimal. The most energy-efficient speed for these moths is 2-3 metres per second", says Kajsa Warfvinge.

However, the aim and purpose of the flight determines which speed is most beneficial. If the moths want to stay in the air for as long as possible, they should preserve their energy and maintain a speed of about 2.5 metres per second. If the goal is to fly far, they should increase their speed to about 4 metres per second. Despite the air resistance and the fact that they are unable to fly for the same amount of time, this is the optimal speed for long distances.
-end-


Lund University

Related Moths Articles:

New to science New Zealand moths link mythological deities to James Cameron's films
In an unexpected discovery, two species of macro-moths were described as new species endemic to the South Island, New Zealand.
Four new species of plume moths discovered in Bahamas
Deborah Matthews hunts for plume moths in darkness, waiting for the halo of her headlamp to catch a brief flicker.
Russian scientists make discovery that can help remove gypsy moths from forests
The caterpillars of Lymantria dispar or Gypsy Moth are voracious eaters capable of defoliating entire forests.
Deaf moth evolves sound-production as a warning to outwit its predator
A genus of deaf moth has evolved to develop an extraordinary sound-producing structure in its wings to evade its primary predator the bat.
Antennal sensors allow hawkmoths to make quick moves
All insects use vision to control their position in the air when they fly, but they also integrate information from other senses.
Austrian-Danish research team discover as many as 22 new moth species from across Europe
Following a long-year study of the family of twirler moths, scientists from the Tyrolean State Museum, Austria and the Zoological Museum of the University of Copenhagen have discovered a startling total of 44 new species, including as many as 22 species inhabiting various regions throughout Europe.
Moths and magnets could save lives
Rice University bioengineers have combined a virus that infects moths with magnetic nanoparticles to create a potential new therapy for inherited genetic diseases like muscular dystrophy, sickle cell, cystic fibrosis, spinal muscular atrophy and some forms of cancer.
Moths survive bat predation through acoustic camouflage fur
Moths are a mainstay food source for bats, which use echolocation to hunt their prey.
Tropical moths in the mountains are larger
Researchers from Friedrich Schiller University Jena (Germany) and two further universities have measured more than 19,000 tropical moths from 1,100 species to find out whether their size varies with elevation.
The nocturnal pollinators: Scientists reveal the secret life of moths
A new study suggests moths have an important but overlooked ecological role -- dispensing pollen over large distances under the cover of darkness.
More Moths News and Moths Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#542 Climate Doomsday
Have you heard? Climate change. We did it. And it's bad. It's going to be worse. We are already suffering the effects of it in many ways. How should we TALK about the dangers we are facing, though? Should we get people good and scared? Or give them hope? Or both? Host Bethany Brookshire talks with David Wallace-Wells and Sheril Kirschenbaum to find out. This episode is hosted by Bethany Brookshire, science writer from Science News. Related links: Why Climate Disasters Might Not Boost Public Engagement on Climate Change on The New York Times by Andrew Revkin The other kind...
Now Playing: Radiolab

Breaking Bongo
Deep fake videos have the potential to make it impossible to sort fact from fiction. And some have argued that this blackhole of doubt will eventually send truth itself into a death spiral. But a series of recent events in the small African nation of Gabon suggest it's already happening.  Today, we follow a ragtag group of freedom fighters as they troll Gabon's president - Ali Bongo - from afar. Using tweets, videos and the uncertainty they can carry, these insurgents test the limits of using truth to create political change and, confusingly, force us to ask: Can fake news be used for good? This episode was reported and produced by Simon Adler. Support Radiolab today at Radiolab.org/donate.