Without insect pollination, many plant species – including crops – cannot reproduce. Bumble bees are of particular importance, but as new research shows, their livelihood could be affected by malnutrition.
Bees are an important factor for our environment and our sustenance. Without insect pollination, many plant species – including various crops – cannot reproduce.
“Bee mortality therefore affects food supply for human beings,” stated Professor Sara Leonhardt, in a statement. All of the worldwide more than 20,000 bee species need to be considered. Among these, bumble bees are of particular importance besides the famous honey bee.
“Bees obtain most of their nutrients from their main food sources, which are nectar and pollen. While nectar is mainly a source of carbohydrates, pollen contains most of the other necessary nutrients: proteins, fat, minerals and vitamins. Until today, most bee researchers assumed that bees, like other herbivores, mainly consider the protein content when choosing their food,” Professor Leonhardt explained.
Using a two-step mechanistical approach that included learning and feeding experiments, the group established a new way to literally keep a close eye on the feeding habits of insects. As a first step, learning experiments helped the scientists to establish the bumble bees’ preference for certain nutrients.
A small amount of fatty acids was added to pollen to increase its fat content. The researchers found that bumble bees could clearly differentiate between normal pollen and pollen with increased fat content and did show a clear preference for normal pollen. Surprisingly, the bumble bees made no clear distinction when the pollen amino acid content was altered in the same way.
Subsequent feeding experiments looked at which nutrients actually affect the bumble bees’ foraging behavior and what the consequences are for their survival and reproductive capabilities.
“The more fat the pollen contained, the less the bumble bees consumed that pollen,” Leonhardt concluded. Bumble bees actually accepted death over having to consume the high-fat pollen. The work group therefore concluded that fat in pollen adversely affects the bumble bees’ reproductive capabilities and survival, which is why it is being avoided.
