Plants attract their pollinators, among other things, with the scent of their flowers. Scientists from the University of Salzburg have investigated what happens when global warming affects these odors. They simulated a warming of five degrees Celsius and observed the effects on various crops and insect species.
The effects were strongest for strawberries: their floral scent was no longer perceptible, with correspondingly negative consequences for crop yields, the Austrian Science Fund FWF reported on Monday.
In his Lise Meitner project, funded by the FWF, Brazilian entomologist Guaraci Duran Cordeiro, in collaboration with Stefan Dötterl, head of the Working Group on Plant Ecology and the Botanical Garden in Salzburg, examined how warming affects the relationship between beneficial plants of three plants. families and pollinators. Specifically, it concerned buckwheat, rapeseed and strawberries, but also western honey bees, dark bumblebees (photo below) and red mason bees.
Complex floral scents analysed
First, the floral scent intensity and chemical composition of the three crops were analyzed using gas chromatography and mass spectrometry for the two temperature scenarios “optimal” and “plus five degrees”. “There are very complex floral scents made up of as many as 200 chemical components. After all, rapeseed and buckwheat have about twenty components, and the scent of strawberry blossoms has five,” Cordeiro said in an FWF broadcast.
The odor components from both scenarios were then synthetically recreated and tested on the antennae of the pollinating insects to determine whether they elicit a physiological response. Since it is the main ingredients of the fragrances that elicit the strongest response from the insects, the researchers are clear: The fewer ingredients a floral scent has and the more sensitive the main ingredients are to heat, the less likely the plant is in the face of climate change. .
The rapeseed clearly has a good hand here, the chemical cues from its odors remained unaffected even in the elevated temperature scenario. Although buckwheat had a significantly reduced odor intensity in the “plus five degrees” scenario, the composition of the chemical signal remained recognizable to the pollinators, according to the researchers.
No strawberry smell at five degrees plus
The strawberries, on the other hand, couldn’t keep up with the Earth’s climate: at plus five degrees Celsius, they no longer produced a perceptible floral scent. So they could not be found by bees, bumblebees and the like. “Lower attractiveness of the flowers to pollinators could negatively impact ecosystem functioning and crop yields,” the researchers write in a paper currently published as a preprint only.
Although visual stimuli are also important for attracting pollinators, the researchers emphasize that these alone are often not enough. For example, Cordeiro specifically studied nocturnal bees, for whom the scent of flowers is an important sensory clue to their host flowers. Typically, bees are diurnal, but about one percent of the described species are nocturnal — and these are effective pollinators of regional fruit crops in Brazil, for example, the researcher writes in an article published in the journal Agronomy.
Source: Krone
I’m Wayne Wickman, a professional journalist and author for Today Times Live. My specialty is covering global news and current events, offering readers a unique perspective on the world’s most pressing issues. I’m passionate about storytelling and helping people stay informed on the goings-on of our planet.
