Bees 'mummified' over 3,000 years ago discovered in southwest Portugal

X-ray micro-CT of a male Eucera inside its nest. (Fernando Muñiz)

Bees that existed during the time of the pharaohs that were found 'mummified' inside cocoons in Portugal could hold some clues to combatting climate change, researchers say.

A recent study, published in the journal Palaeontology, found the Eucera bees preserved in their brood cells dating to the end of the last major 'ice age' in southwest Portugal.

Scientists said they also found remnants of a pollen that revealed the bees' preference for one type of plant.

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The study described the bees' state of fossilization as 'extremely rare,' considering the skeleton of this insect's type decomposes easily and these date back 3,000 years.

Researchers said this level of conservation makes it easier to identify the type of bee, sex, and the pollen left by the mother when creating the cocoon.

The study also further highlighted how bees are an important group of pollinating insects and include over 20,000 different species. Around three quarters of all wild bee species nest in the soil and spent most of their life cycle underground, the study said, which ensures the preservation of their nesting habitats.

"We know that bees pollinate 70 per cent of the crops that people eat and 30 per cent of food for livestock. Human activity, such as intensive farming, the use of pesticides and insecticides and climate change are creating a situation where one in every ten species of bees is in danger of extinction in Europe," said University of Seville professor and study researcher Fernando Muñiz in a news release Thursday.

The study said while how the bees died is unknown, a shortage of oxygen caused by sudden flooding and a subsequent drop in nightly temperature is likely the cause.

Portugal's southwest coast experienced slightly colder periods with greater rainfall during winter when these bees existed, and researchers said those were favourable climate conditions to preserve these fossils.

Researcher Carlos Neto de Carvalho said this recent discovery may help understand strategies for resilience in the face of climate change, "such as comparing the ecological imbalances caused by natural parameters and the current ones and the way in which they are affecting the bee species of today."