Bee species with larger brains learn better

Having a larger brain has a direct impact on bee learning, a theory already demonstrated in birds and primates, which is highlighted in a study published in the Royal Society Open Science, led by a scientific team from CREAF and the Doñana Biological Station (CSIC).

A bee enclosed in a glass tube, at the end two strips of cardboard, one blue and one yellow, two colours that the bee can distinguish very well, the blue one soaked in sugar, the yellow one in water. Will it know how to associate colour with reward? And if we change species, will it learn the same? Birds and primates have shown that species with bigger brains are smarter, they learn better. Now, the scientific study Brain size predicts learning abilities in bees led by CREAF and the CSIC Doñana Biological Station shows for the first time that this theory also holds true in bees. Bee species with larger brains, both in absolute terms and relative to body size, have a greater capacity for learning.

"There is a huge variation in the size of the brain of bee species, and this can greatly influence their ability to adapt to environmental changes. "

MIGUEL ÁNGEL COLLADO, researcher at the Doñana Biological Station (CSIC) and at CREAF.

Miguel Ángel Collado, researcher at the Doñana Biological Station (CSIC) and CREAF carried out the experiment that corroborates this statement. He performed the test 7 times, changing the position of the strips, with each of the 120 bees collected in fields and gardens in Andalusia, so that they would learn to associate colour with reward. Of the 16 different bee species in total, he found that most species learn to associate a colour with a reward, but those with larger brains do better than those with smaller brains. Confirming that the theory holds true in invertebrates is an important step.  "Although their brains are smaller and simpler than those of vertebrates, we know that there is a huge variation in size between species and that this can greatly influence their ability to adapt to environmental changes," according to Miguel Ángel Collado.

The street university

Bees with larger brains show better cognitive skills and are therefore better adapted to urbanization and changing environmental conditions.

There are more than 20,000 bee species worldwide, but not all of them respond equally to environmental pressures. While some species are drastically reducing their populations, others are thriving in humanised ecosystems. Does brain size play a role in these differences in adaptation? "To survive in a city you have to be very clever, you have to adapt to complex and changing landscapes to locate flowers and nesting sites. So if bees with bigger brains have more cognitive skills, we know that they will be the ones that adapt better to urbanisation or other changing conditions," explains Ignasi Bartomeus, researcher at Doñana Biological Station (CSIC).

"To survive in a city the bee must be very smart, adapt to complex and changing landscapes to locate flowers and nesting areas"

IGNASI BARTOMEUS, researcher at the Doñana Biological Station (CSIC).

Investing in brain tissue is costly, so it only makes sense when there is a benefit. Previous studies have already confirmed that species with higher cognitive demands - for example, specialised bees that need to locate particular floral resources - have evolved to acquire larger brains. "Much remains to be understood, we are only beginning to understand the enormous capacity of small bee brains," concludes Daniel Sol from CREAF.

"Much remains to be understood, we are only beginning to understand the enormous capacity of small bee brains"

DANIEL SOL, researcher at CREAF.

Reference article:

Collado MÁ, Montaner CM, Molina FP, Sol D, Bartomeus I. 2021 Brain size predicts learning abilities in bees. R. Soc. Open Sci. 8: 201940. https://doi.org/10.1098/rsos.201940