A team of scientists from Academia Sinica in Taiwan and Columbia University in the US has discovered that cooperative groups of burying beetles (Nicrophorus nepalensis) achieve higher breeding success across a range of temperatures, hinting at possible predictions about the ways animal societies and humans adapt to climate change.
Many scientists believe that humans and social insects dominate the earth because of their ability to form cooperative societies. Our ancestors learned to cope with a range of different environments by cooperating with each other - effectively becoming generalists. However, testing the idea that cooperation allows animals to become generalists capable of surviving across a range of surroundings - an idea known as the €social conquest hypothesis€ - is difficult.
The research team examined the ecological consequences of social cooperation among Nicrophorus nepalensis by quantifying the fitness of cooperative and non-cooperative groups at different elevations and temperatures. Feeding their larvae dead animals, the beetles either fight each other to ensure that their own young get exclusive access to the food source, or work together in burying the food to prevent flies and other competitors from discovering it. In addition, at higher elevations temperatures were lower but fewer flies were present, whereas lower elevations had higher temperatures but more flies.
The research, which was published in eLife, revealed that cooperative groups of beetles performed as thermal generalists with similarly high breeding success at all temperatures and elevations, whereas non-cooperative groups yielded higher breeding success only at intermediate temperatures and elevations.
€This study provides the first experimental evidence consistent with the social conquest hypothesis,€ wrote the authors. €Ultimately, studying the ecological consequences of cooperation may not only help us to understand why so many species of social insects have conquered the earth, but also to determine how climate change will affect the success of these and other social species, including our own.€

This insect has nature's highest-pitched call

Katydids (or bushcrickets) are insects known for their acoustic communication, with the male producing sound by rubbing its wings together (stridulation) to attract distant females for mating.
Scientists from the universities of Lincoln, Strathclyde and Toronto located a new genus with three new species of katydid in the rainforests of Colombia and Ecuador. These insects were found to produce the highest ultrasonic calling songs known in nature, with males reaching 150 kHz. The calling frequencies used by most katydids range between 5 kHz and 30 kHz. The nominal human hearing range ends at around 20 kHz. For this reason, the new genus has been named Supersonus.
Dr Fernando Montealegre-Z, from the School of Life Sciences, University of Lincoln, UK, said: "To call distant females, male katydids produce songs by 'stridulation' where one wing (the scraper) rubs against a row of 'teeth' on the other wing. The scraper is next to a vibrating drum that acts like a speaker. The forewings and drums are unusually reduced in size in the Supersonus species, yet they still manage to be highly ultrasonic and very loud."
"Using a combination of state-of-the-art technologies, we found that Supersonus creates a 'closed box' with its right wing in order to radiate sound. Human-made loud speakers also use this system to radiate sound. Large speakers radiate low frequencies, while small speakers emit high frequencies. So, these reduced wings are responsible for tuning their calling songs at such high frequencies."
These insects have lost the ability of flight due to their reduced wing size, so the adoption of extreme ultrasonic frequencies might play a role in avoiding predators, such as bats. Bats can detect their prey's movements using echolocation but can also eavesdrop and detect the calls of singing animals like katydids and frogs. Rainforest katydids have learned to avoid bats by reducing the time spent singing and by evolving an ear that can detect the ultrasonic echolocation calls of the bats. Although some bats can detect 150 kHz, by singing at extreme ultrasonic frequencies, the katydid calls degrade faster with distance so that a flying bat will find it harder to hear the signal.
Dr James Windmill, from the Centre of Ultrasonic Engineering, University of Strathclyde, added: "These insects can produce, and hear, loud ultrasonic calls in air. Understanding how nature's systems do this can give us inspiration for our engineered ultrasonics."
The paper 'Shrinking wings for ultrasonic pitch production: hyper intense ultra-short-wavelength calls in a new genus of neotropical katydids (Orthoptera: Tettigoniidae)' has been published in the international journal PLOS ONE. The research was supported by a grant from the National Geographic Society Global Exploration Fund, a regional grant program for residents of Northern Europe.
"We are delighted that the National Geographic Society's research grant has made it possible for the team to make new scientific advances in the study of bushcrickets. Projects like this give us a better understanding of the insect world," said Joakim Mornef¤lt, Executive Director of the National Geographic Society Global Exploration Fund Northern Europe.

Insects don't use the sun as a compass, but build a mental map to navigate

It has been claimed that bees solve difficult maths problems and that their tiny brains are better than computers.
And now a new study suggests that the insects rely on a built in €sat nav' system to find their way around.
Honeybees make €mental maps' of their home ranges allowing them to pinpoint destinations miles away from their hives.
While humans, sharks and even pigeons are known to use this technique, it was popularly thought that bees rely solely on the sun's position to find their way back to their hive.
Dr James Cheeseman of Auckland University in New Zealand, said: €Only 50 years ago the claim any non-human animal had a cognitive map was deeply controversial because it suggested a computational theory of mind. The question of whether insects do is a frontier question.'
To come up with their finding, scientists captured and anaesthetised honeybees and shifted some of their circadian (body) clocks by six hours to disorientate them.
They fitted them with tiny radar transponders to track their movements after releasing them in a different location.
The researchers reasoned that if the bees did rely on the sun as a compass, then the alteration to their body clocks would disrupt their ability to find their way home.
They found that when the bees with altered body clocks were let out in a field in Brandenburg, Germany, they returned with similar speed and accuracy as those that had not been put to sleep, according to the study published in the journal Proceedings of the National Academy of Sciences.
Dr Cheeseman said: €The results suggest bees may navigate by a mental terrain map in addition to learned sun-compass directions.'
It is known that mammals can navigate areas by making cognitive maps - a mental representation of landmarks like rocks, trees and rows of bushes. But it was unclear as to whether insects possess the same skill.
€The results we report imply the bee is like mammals and birds in that its brain constructs an integrated, metric cognitive map,' he said.
The discovery is remarkable because the brain of the bee is tiny and lacks structures such as the hippocampus, which is used in navigation.
But the insects must somehow construct a type of map that includes information on directions, distances, diverse landmarks, feeding sources and terrain features to permit the complicated computation of an efficient journey home.