Monthly Archives: July 2014

The polyglot bee

by Piter Kehoma Boll

ResearchBlogging.orgCommunication is essential for humans, and so it is for other animals that live in groups. It is intersting that even though modern humans only came to be about 200,000 years ago, the number of languages which evolved in our species since then is huge. And two people who speak different languages usually cannot understand each other. Even simple hand gestures, like the beckoning sign, meaning “come here”, is rather different between cultures. Most of our communication is not inherited, but rather learned.

Three different ways to say “come here” with gestures. The first two are western style and the last is eastern style. Photos taken from from.onverse.com (left), scmorgan.com (center) and japanpowered.com (right).

Three different ways to say “come here” with gestures. The first two are western style and the last is eastern style. Photos taken from forum.onverse.com (left), scmorgan.com (center) and japanpowered.com (right).

But what about communication in other animals? Is it possible that different languages evolve in separate populations so that one group cannot understand what the other is saying?

One well-known and well-studied form of communication in animals is the honeybee waggle dance, used by honeybees to indicate the location of a food source to others. This dance informs the direction and distance of the food source from the hive in order to guide other bees to the right spot.

 

Scheme of the bee waggle dance. Picture by Wikimedia Common’s user Audriusa.*

Scheme of the bee waggle dance. Picture by Wikimedia Commons’ user Audriusa.*

Basically, what the bee does is to move in a path forming an 8-shaped figure. The angle of the dance in relation to the hive’s orientation indicates the angle of the food source in relation to the sun. The middle part of the dance, which represents the part where the two loops of the 8 overlap, is done with a frenetic waggle. The duration of this waggle part of the dance informs the distance of the food source from the hive.

There are many subspecies of honeybees and the waggle dance may have become different in each of them by evolution, creating different dance languages or dialects. It’s difficult, however, to compare those dialects because they can be adjusted to different conditions in the environment, so two hives must be in the very same environment to be compared. The best way to compare differences would be rearing different bee species in the same hive. But that is difficult because bees tend to attack foreigners as they are easily identified by smell.

Yet after some attempts, a group of scientists from Zhejiang University in China was able to create some mixed hives of European honeybees (Apis mellifera ligustica) and Asian honeybees (Apis cerana cerana). They observed the behavior of individuals from both species in the hive in order to find differences between their dances and how they communicate with each other.

Appis cerana cerana (left) and Apis mellifera ligustica (right). Photos by Wikimedia Commons' User Viriditas* (left) and Charles Lam* (right). Extracted from commons.wikimedia,org

Apis cerana cerana (left) and Apis mellifera ligustica (right). Photos by Wikimedia Commons’ User Viriditas* (left) and by Charles Lam** (right). Extracted from commons.wikimedia,org

The results were impressive. The dances were rather different for each species, but bees retained part of their original dance in mixed hives and changed other part. There was no difference in communicating the direction of food between the species when reared in the mixed hive, but Asian bees showed longer waggle duration than European bees to inform the same distance. Nevertheless, both species were able to understand the dance from individuals of the other species and reach the food source without trouble. Even when another food source in the same direction was closer to the hive, bees chose the more distant source informed in the dance.

It seems then that bees are excellent at understanding foreign languages, but not as good at “speaking” them. They retain a strong accent, but are able to be understood anyway.

Moreover, even though European and Asian bees are estimated to have diverged more than six million years ago, they still can understand each other. This indicates that the waggle dance is a quite conserved behavior.

The waggle dance seems to have a possible genetic part, such as the duration of the waggle, since it wasn’t affected by the mixed environment. But it also has a learned part, such as the information about the direction of food.

Those results raise good questions and indicate a path to follow to study and better understand social learning, i.e., learning from information gathered from other individuals rather than by personal experience.

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References:

Su, S.; Cai, F.; Si, A.; Zhang, S.; Tautz, J. & Chen, S. 2008. East Learns from West: Asiatic Honeybees Can Understand Dance Language of European Honeybees PLoS ONE, 3 (6) DOI: 10.1371/journal.pone.0002365

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These works are licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

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This work is licensed under a Creative Commons Attribution-ShareAlike 2.0 Generic License.

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Filed under Behavior, Ecology, Entomology, Zoology

Elephants don’t have fun painting

by Piter Kehoma Boll

ResearchBlogging.orgElephants are considered animals of high intelligence and social complexity, able to solve puzzles, use tools, show empathy and have self-awareness. Moreover, of course, they have an amazing memory.

When in captivity, elephants use to become stressed and bored, which leads many institutions that have them to develop programs of specific activities for enrichment in order to improve the well-being of these animals.

One of those common activities is painting, where the elephants paint on a canvas while holding a painting brush with their trunks. Despite this and other activities usually being considered good ways to reduce stress in elephants, there are no rigorous studies testing such assumptions.

An elephant painting at Melbourne Zoo. Photo from the original article by English et al., 2014.

An elephant painting at Melbourne Zoo. Photo from the original article by English et al., 2014.

A group of researchers from the University of New England, Australia, decided to test the effects of painting activities on elephants in captivity. They used four Asian elephants from the Melbourne Zoo which were used to the activity of painting.

Each morning, two of the four elephants were taken to the painting area, where one received food and the other painted. The painting sessions lasted less than five minutes.

The behavior of the elephants was monitored some hours before and some hours after the painting sessions and divided in three situations: (1) days in which the elephant painted, (2) days in which the elephant did not paint, but others did, and (3) days in which no elephant painted.

The final results showed that the painting sessions did not alter significantly the behavior of the elephants. There were no evidences of reduction in the stress levels of animals submitted to the painting sessions. Even during the painting, at least two of the elephants did not seem to be very interested in the activity, paying more attention to the keeper than to the canvas.

So we can conclude that painting canvas did not alter the humor of elephants and the activity has the sole purpose of public entertainment and fund raising by selling the canvas. The elephants remain as bored as they have always been in captivity.

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Reference:

English, M.; Kaplan, G. & Rogers, L. 2014. Is painting by elephants in zoos as enriching as we are led to believe? PeerJ, 2 DOI: 10.7717/peerj.471

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