Higher mean temperatures as associated with climate change can have a severe impact on plants and animals by disrupting their mutually beneficial relationship: The pasque flower (Pulsatilla vulgaris), for example, is very sensitive to rising temperatures by flowering earlier each year, whereas one of its major pollinators, a solitary bee species, does not quite keep pace by hatching earlier.
Higher mean temperatures as associated with climate change can have a severe impact on plants and animals by disrupting their mutually beneficial relationship: The pasque flower (Pulsatilla vulgaris), for example, is very sensitive to rising temperatures by flowering earlier each year, whereas one of its major pollinators, a solitary bee species, does not quite keep pace by hatching earlier. In the worst case, this may cause the seed production of the plant to decrease and impair reproduction while requiring the bee to switch to other plants to forage on to compensate for the lack of food supply.
This is the key finding of a new study conducted by scientists from the University of Würzburg which has been published in the journal Plos One. Dr. Andrea Holzschuh from the Department of Animal Ecology and Tropical Biology (Zoology III) and PhD student, Sandra Kehrberger, were in charge of the study.
The times of flowering and hatching must coincide
"We studied the impact of temperature on two solitary bee species that emerge in spring and on Pulsatilla vulgaris, one of the earliest flowering plants," Sandra Kehrberger describes their experiment. The scientists were particularly interested in how different temperatures in winter and spring affect the hatching time of the European orchard bee (Osmia cornuta) and of the red mason bee (Osmia bicornis) as well as the onset of flowering in the pasque flower.
The phenological synchrony of the two events, hatching and flowering, is crucial in the life of both plant and bee: "For solitary bees, it is all about the correct timing of hatching in spring when the growing season starts since already a short period of time without flowering plants that provide food can have negative consequences for the bees' survival and the number of offspring," Andrea Holzschuh explains. But the timely onset of flowering is also essential for plant species that flower at the beginning of the growing season and rely on solitary pollinators. "A lack of pollinators can have serious consequences for the plants and their reproductive success," Sandra Kehrberger adds.
Read more at University of Würzburg
Image: The scientists performed their experiment on chalk grasslands as shown here. The wooden post is fitted with hatching tubes complete with bee cocoons and nesting structures. (Credit: Sandra Kehrberger)
