Two little bees flying in the desert? Explore the bee habitat in the desert oasis

Produced by: Science Popularization China

Author: Wu Yu

Producer: China Science Expo

Two little bees flying among the flowers...

(Photo source: veer photo gallery)

Hiding your achievements and fame

When people mention bees, the first thing that comes to mind may be that they collect honey and sting people, but in fact, the more important role of bees is that they can pollinate many wild flowering plants in the world, including many economic crops that are vital to humans.

Nearly 90% of wild flowering plant species worldwide rely to some extent on animal-mediated pollination for reproduction, and bees are considered the most important crop pollinator group worldwide. There are approximately 20,000 species of bees worldwide, and approximately 1,400 species in China.

The reason why bees can become important crop pollinators is that they have a high pollination efficiency. Their pollination efficiency is mainly related to the following factors:

First, the process of bees collecting nectar is a mutually beneficial symbiotic relationship, in which the bees get food and the plants complete the reproductive process; second, the bees' bodies are covered with branched hairs, which enable pollen grains to attach and transport effectively, facilitating pollination and pollination; finally, bees tend to collect nectar and pollen from specific flower species because their body structure has adapted to these flower species, which can greatly improve collection efficiency.

Bees collecting pollen

(Image source: Wikipedia)

Bee pollination can not only directly improve the product and quality of crops, but also maintain the balance and biodiversity of the ecosystem. However, since bees always need flowers to collect nectar, many people may subconsciously think that the place with the most bee species diversity may be in the warm and humid tropics.

But counterintuitively, after collecting distribution information data on more than 20,000 species of bees worldwide and conducting statistical analysis, some researchers were surprised to find that under certain circumstances, the number of bee populations in arid areas is higher than that in tropical areas.

You are a bee, it is a sand

Why are there more species of bees in desert areas?

As we all know, deserts are almost completely unsuitable for plant growth: deserts cannot provide soil conditions for plant growth, and desert soil is mainly sandy, which makes it difficult to retain water and fertilizer, and is very barren; in addition, the amount of precipitation in deserts is pitifully small, and the water evaporates very quickly, and the relative humidity is low; in addition, the temperature in deserts is an extreme case of continental climate, with very high temperatures during the day due to direct sunlight, and the ground temperature drops very quickly at night, even to below 0°C. As a result, the temperature difference between day and night in deserts is very large, and can be as high as 50°C or more.

Since bees need to collect nectar, the key condition for the existence of more types of bees in the desert must be the existence of more types of flowers in the desert. The existence of flowers requires the following conditions: suitable growth temperature, sufficient light, sufficient water and substrate soil for flower growth.

Of these conditions, the only one that the desert can satisfy is light! This also seems very counterintuitive.

So is there a situation where the desert can simultaneously meet several conditions for flowers to grow and bloom?

Of course there is, and that is the "timely rain" in the desert.

When certain climatic conditions are met, it will rain heavily in the desert, and the amount of rainwater will be sufficient. The arrival of rainwater will completely change the situation in the desert. Part of the rainfall will be converted into water vapor and rise into clouds, blocking the sun from directly hitting the surface and controlling the ground temperature rise process. At night, because water vapor is also a strong greenhouse gas, it will help the desert maintain temperature, thereby reducing the temperature difference between day and night in the desert. The ground in the desert absorbs a lot of water, resulting in an increase in its ability to retain water and fertilizer, creating soil conditions for the growth of flowers.

When the "timely rain" comes, the temperature, light, water and soil conditions are all there, and everything is ready, so the seeds underground in the desert begin to stir. Plants that have adapted to the desert environment can quickly germinate and bloom in a short period of time, and they can attract animals from hundreds of kilometers away to come for food. Bees, a hardworking little animal, are extremely sensitive to the surrounding environment and can quickly sense these signals and then reach the desert as quickly as possible, so different types of bees gather in the desert.

Although there are more trees in tropical areas, the food they provide to bees is limited. In the desert, the climate and environment change frequently, and the distribution of resources varies from year to year, so there may be more new species. With more species, bees naturally have more food choices. Therefore, under certain conditions, the number of bee species in desert areas is more than that in tropical areas.

Desert is OK, but living in the desert is not OK

The reason why many different species of bees like to live in the desert is ultimately because there is an environment in the desert that is suitable for the survival of bees at a certain period of time - there are many flowers.

However, with the impact of human activities, environmental degradation and climate warming, the interdependent ecological relationship between bees and plants has been destroyed. Studies have shown that species abundance and geographical distribution are related to climate change, and the number of bumblebee species has decreased significantly with abnormal temperature changes.

Secondly, the overuse of chemical pesticides has also led to the disappearance of a large number of bees. After bees are exposed to pesticides, there may be the following results: pesticides directly kill bees; pesticides affect the bees' nervous system and cause metabolic disorders, change their behavior patterns, and make it impossible for them to find the hive; make it difficult for them to avoid natural enemies or die due to difficulty in finding food.

The invasion of alien species also breaks the original balance of the ecosystem, thus affecting the survival of native species. For example, due to the impact of Italian honey bees, the population of Chinese honey bees has decreased by more than 80%.

(Photo source: veer photo gallery)

Bees are indispensable to us. A large number of crops and plants need bee pollination to continue to reproduce. If the number of bees continues to decrease, without bee pollination, the shape of some fruits and vegetables will be easily deformed, and the pollen of many plants will not be spread, resulting in a sharp decline in the number of certain plants in the region. Nutritious crops such as fruits, nuts and many vegetables will gradually fail to grow effectively, which may eventually lead to an imbalance in human diet.

Conclusion

After learning about their "strange habit" of liking the desert, we should also remember that they don't like to live in the desert. Let's take action together to protect bees and maintain the balance of the ecosystem.

References:

[1]Orr, Michael C et al. “Global Patterns and Drivers of Bee Distribution.” Current biology : CB vol. 31,3 (2021): 451-458.e4. doi:10.1016/j.cub.2020.10.053

[2]Karp, Daniel S et al. “Crop pests and predators exhibit inconsistent responses to surrounding landscape composition.” Proceedings of the National Academy of Sciences of the United States of America vol. 115,33 (2018): E7863-E7870. doi:10.1073/pnas.1800042115

[3]Requier, Fabrice et al. “Bee and non-bee pollinator importance for local food security.” Trends in ecology & evolution vol. 38,2 (2023): 196-205. doi:10.1016/j.tree.2022.10.006

[4]Houghton, John Theodore et al. “Climate change 2001: the scientific basis.” Foreign Affairs 81 (2002): 208.

[5]Garibaldi, Lucas A et al. “Policies for Ecological Intensification of Crop Production.” Trends in ecology & evolution vol. 34,4 (2019): 282-286. doi:10.1016/j.tree.2019.01.003

[6]Soroye, Peter et al. “Climate change contributes to widespread declines among bumble bees across continents.” Science (New York, NY) vol. 367,6478 (2020): 685-688. doi:10.1126/science.aax8591