Scientists date the origin of the cacao tree to 10 million years ago

Selected coverage: Science Magazine, The Times Scotland, Daily Mail, Tech Times, Live Science,

With Shauna Hay, Royal Botanic Garden Edinburgh, UK

New research shows that cacao trees evolved around 10 million years ago, earlier than previously believed. Considerable genetic variation might remain to be discovered among wild cacao populations, which could be crossbred with cultivated cacao for greater resistance to disease and climate change.

Chocolate, produced from seeds of the cacao tree Theobroma cacao, is one of the most popular flavors in the world, with sales around 100$ billion dollars per year. Yet, as worldwide demand increases, there are fears the industry will fail to cope with growing public hunger for the product. The main problem, common to many crops, is the lack of genetic variation in cultivated cacao, which makes it vulnerable to pests and blights. Lack of genetic variation also puts cacao trees at risk from climate change, jeopardizing the long-term sustainability of the industry.

Now, however, new research suggests the cacao tree is much older than previously realised — and may have close relations capable of sustaining our sweet-toothed appetites.

“Studies of the evolutionary history of economically important groups are vital to develop agricultural industries, and demonstrate the importance of conserving biodiversity to contribute towards sustainable development. Here we show for the first time that the source of chocolate, Theobroma cacao, is remarkably old for an Amazonian plant species,” says Dr James Richardson, a tropical botanist at the Royal Botanic Garden Edinburgh, UK, and lead author of the study.

Together with researchers from the University of Rosario and the University of the Andes in Colombia, the University of Miami, USA, and the United States Department of Agriculture (USDA), Richardson found that Theobroma cacao is one of the oldest species in the genus Theobroma, having evolved around 10 million years ago. At the time, the Andes were not yet fully elevated, which explains why cacao trees today occur on both sides of the Andes.

The species’ early evolutionary origin is good news: it suggests that cacao has had enough time to diversify genetically, with each wild population adapting to its local habitat. Wild populations of cacao across the Americas may therefore be treasure troves of genetic variation, which could be bred into cultivated strains to make the latter more resistant to disease and climate change, and perhaps even create new flavors of chocolate.

“After ten million years of evolution we should not be surprised to see a large amount of variation within the species, some of which might exhibit novel flavours or forms that are resistant to diseases. These varieties may contribute towards improving a developing chocolate industry,” says James Richardson.

The researchers already plan to return to South America to sample all species related to cacao and investigate the characteristics of their native populations.

“We hope to highlight the importance of conserving biodiversity so that it can be used to augment and safeguard the agricultural sector. By understanding the diversification processes of chocolate and its relatives we can contribute to the development of the industry and demonstrate that this truly is the Age of Chocolate,” says coauthor Dr Santiago Madriñán of the University of the Andes in Bogotá, Colombia.

The study is published in the open-access journal Frontiers in Ecology and Evolution.

EurekAlert! PR: http://www.eurekalert.org/pub_releases/2015-11/f-sdt110515.php

Study: http://journal.frontiersin.org/article/10.3389/fevo.2015.00120/full

Unlike people, monkeys aren’t fooled by expensive brands

Selected coverage: Le Monde, Yale News, L’Obs, Yahoo, Discover Magazine, Sydney Morning Herald, Herald Scotland, Daily Mail, Tech Times

In at least one respect, Capuchin monkeys are smarter than humans — they don’t assume a higher price tag means better quality, according to a new Yale study appearing in the open-access journal Frontiers in Psychology.

People consistently tend to confuse the price of a good with its quality. For instance, one study showed that people think a wine labeled with an expensive price tag tastes better than the same wine labeled with a cheaper price tag. In other studies, people thought a painkiller worked better when they paid a higher price for it.

The Yale study shows that monkeys don’t buy that premise, although they share other irrational behaviors with their human relatives.

“We know that capuchin monkeys share a number of our own economic biases. Our previous work has shown that monkeys are loss-averse, irrational when it comes to dealing with risk, and even prone to rationalizing their own decisions, just like humans,” said Laurie Santos, a psychologist at Yale University and senior author of the study. “But this is one of the first domains we’ve tested in which monkeys show more rational behavior than humans do.”

Rhia Catapano, a former Yale undergraduate who ran the study as part of her senior honors thesis, along with Santos and colleagues designed a series of four experiments to test whether capuchins would prefer higher-priced but equivalent items. They taught monkeys to make choices in an experimental market and to buy novel foods at different prices. Control studies showed that monkeys understood the differences in price between the foods. But when the researchers tested whether monkeys preferred the taste of the higher-priced goods, they were surprised to find that the monkeys didn’t show the same bias as humans.

Santos and colleagues think that differences in the response of humans and capuchins could stem from the different experiences that monkeys and people have with markets and how they behave.

“For humans, higher price tags often signal that other people like a particular good.” Santos noted. “Our richer social experiences with markets might be the very thing that leads us — and not monkeys — astray in this case.”

EurekAlert! PR: http://www.eurekalert.org/pub_releases/2014-12/yu-upm120114.php

Study: http://journal.frontiersin.org/article/10.3389/fpsyg.2014.01330/full