As you reached our website you can imagine that the answer to this question is YES. And we need to take action to stop this. But which bees are in danger? When we refer to bees most of us think about the honey bee, or in scientific terms to the Apis mellifera. Well, it is now time that you realise that there are more than 20 thousand (!) different species of bees, and the honey bee is just one of these.
The European red list of bees[i] identifies the species of bees that are threatened with extinction on a regional level around Europe. At the moment of the publication in 2014, there were a total of 1965 bee species included in this list. Despite the intense research work done to redeem this list, for more than half of these species (1101) the risk of extinction could not be evaluated due to lack of scientific data.
Surprisingly, also for the well known Honey Bee the risk of extinction is not really clear. This is due to the fact that this species is intensively used for the production of honey all around the world, therefore the number of colonies is still quite high. When we talk about the Honey bee, the problem is therefore not related to the number of individuals present around the globe, but is mostly related to the amount of wild colonies that live in our forests. As a matter of fact, we do not know if this specie still even occurs in the wild nor if these wild colonies would be self-sustaining [i].
But what about the other bees?
As you now finally know, apart from the honey bees there are thousands of different species that help us every day by pollinating our trees and most of our crops. Out of the 864 bees species of which the evaluation was possible, 67 bee species are threatened of extinction. Another 101 are near threatened. This might not seem much, but it means that around 1 out of 10 bees is threatened with extinction. When the data about the other species will be available this number will probably increase.
To understand a bit more about the topic, we should first have a brief look at the taxonomy of bees. While all bees are part of the Hymenoptera order, in Europe 6 different families are present, namely the Andrenide, Apidae (of which the honey bee is a member), Colletidae, Halictidae, Megachilidae and Melittidae. Not surprisingly, in all these families there are some species that are threatened with extinction. Percentage of species threatened with extinction vary between families and range from 2% for the Andrenidae up to 18.9% for the Melittidae. As this percentage might be relatively low for some families, it is quite high for others. As a result, this could lead to a great decrease in biodiversity if most species of a family get extinct.
|Family||6 different In Europe|
State of conservation of wild bees: the example of bumble bees
A good example of the actual situation can be made by having a look at the bumble bees (family apidae, genus bombus) population. There are 68 different species of bumble bees present in Europe. Their state of conservation is well studied and could be taken as a sample to assess the overall situation of the European bees. According to the European red list of bees, 45.6% of the bee species of this genus is having a decline in population while 23.6% are threatened with extinction. These numbers can make us realise that the actual situation could be way worse than what was presented at the beginning of this section.
Around the globe many actions have been taken to stop this decline. Unfortunately at the moment the situation is not improving. The 2020 plan of the European Union to bring the solitary bees out of the risk zone has been declared largely ineffective by the European court of auditors itself [ii]. More actions are needed to stop the bee decline. These need to be a combination of different solutions that jointly tackle the different problems that are leading to a decrease in bee populations.
Why are the bee populations decreasing?
There are many factors influencing the decrease in bee populations. One can of course think about the intense use of agrochemicals in modern agriculture. This is of course true, especially for some pesticides. We will take as an example the insecticides of the class of the neonicotinoids that had become very popular in the last years and that had raised many concerns for its effects on the wild fauna.
This type of insecticide is usually applied on the seeds before sowing or directly on the soil. The insecticide is absorbed by the plant and is transported around all its parts, including the flowers. When applied on the ground, it is absorbed in an enormous amount by the plant and the bees can easily reach a lethal dose when feeding on them. When applied on the seeds, the quantity moving in the plant is reduced and bees get mostly stunned and disoriented, possibly affecting their return to the colony[iii].
A study published on “Science” has also shown that under field conditions, neonicotinoids have a negative effect on Bumble bees colony growth and queen production, with a reduction of 85% in the production of new queens [iv]. For these reasons and many others, many organizations around the world are fighting for banning insecticides dangerous for the bees. Although this is of fundamental importance to counteract the decreasing of the bee populations, it is important to know that this is not the only cause of this problem.
Pesticides yes, but what else?
In a review article published in “Science” in 2015, many different causes of bee decline have been investigated. We will now focus on some of them, such as habitat loss, emerging parasites and pathogens, intensification of agriculture and climate change[v]. We will briefly elaborate on each one of these points to give you a better overview of an emerging problem of the modern era.
The expansions of our cities, the increased amount of agricultural fields and deforestation, had caused a continuous habit loss for many bee species. This is not just due to the amount of available land, but also to connected factors, such as the decrease in diversity of floral sources and the nesting opportunities. In fact, while cities increase in size and agriculture is moving more and more to extensive monoculture fields, the availability of flowers are decreasing and often these food sources are separated by areas extensively covered in concrete present in our cities. In addition, in many gardens of modern houses the practice of using tiles or (plastic) grass carpets is increasing, diminishing even further the possibility of finding a food source for bees when crossing the cities.
Intensification of agriculture
The intensification of agriculture is also having detrimental effects on the bee populations for other reasons. We previously mentioned the problems connected to the use of insecticides, but these are not the only agrochemicals used in modern agriculture. In fact, the use of herbicides also have had detrimental effects on the food sources of the bees, as they also exterminate flower producing plants, limiting again bees food sources. But wait… it doesn’t end here.
Another important change in agriculture since 1940 is connected to the use of synthetic fertilisers in the fields that have substituted the previously used nitrogen fixing plants. Plants such as clover and alfalfa, were not just great to enrich our soils, but were also flowering plants that provided an important food source to bees.
In addition, intensive agriculture of single crops in a specific region, has caused bees to have a very monotonous diet. It might seem not an important factor, but by feeding just one type of crop, bees can develop deficiency in some nutrients or cumulate toxins present in low quantities in some flowers, such as for example the glycoside amygdalin in almonds [v].
Emerging parasites and pathogens
Due to the fundamental importance of bee works in agriculture, many bees species have been farmed and exported all around the globe to increase the yields of agricultural fields. This had also the consequence of exporting new parasites and pathogens that were not originally present in some areas. Parasites as the mite Varroa destructor, that was originally associated with Asian colonies since 1960, have spread across Europe, North and South America and recently even to New Zealand [v]. These mites had become a serious threat to the beekeeping industry, not just due to its parasitizing action, but also due to the spread of various diseases that strongly compromise the viability of the colonies[vi].
Last, but not least, bees also have to face the problem of climate change. Although the effect of climate change on bees is not well understood, it is still possible to make some considerations. For example, we know that some bumblebees are poorly adapted to high temperatures. In Spain a movement of some species uphill was registered, to avoid the high temperatures. This can cause a possible decline in their population numbers in the southern edge of their range. Due to increased temperatures worldwide, this migrating effect could be registered in many other parts of the world. In addition, climate change is also causing an increased amount of natural disasters such as floods, storms and droughts. This could have a detrimental effect on many bees species. For example, flooding could seriously harm bee populations that nest or hibernate underground [v].
In conclusion, how does it feel to be a bee in the modern world?
Clearly, we cannot answer this question. But Marla Spivak in a TedTalk in 2013 gave a very interesting answer [iii]. She compared our modern monoculture agricultural field to enormous food deserts. Then she started thinking about how difficult it could be for bees to get to their food source and return back home at the end of the day. We don’t know how it feels to be infected by a bee virus. But we know how it is to have a flu. So now think… You wake up in the morning with a flu, a giant parasite in your back, food poisoning from the food you ate the day before and then… you have to walk 10 kilometres to cross that gigantic food desert to finally get your daily ration of (poisoned) food. Then think, how long would you survive?
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[i] Nieto, A., Roberts, S. P., Kemp, J., Rasmont, P., Kuhlmann, M., García Criado, M., … & De Meulemeester, T. (2017). European red list of bees.
[iii] TedTalk Marla Spivak (2013). https://www.youtube.com/watch?v=dY7iATJVCso
[iv] Whitehorn, P. R., O’connor, S., Wackers, F. L., & Goulson, D. (2012). Neonicotinoid pesticide reduces bumble bee colony growth and queen production. Science, 336(6079), 351-352.
[v] Goulson, D., Nicholls, E., Botías, C., & Rotheray, E. L. (2015). Bee declines driven by combined stress from parasites, pesticides, and lack of flowers. Science, 347(6229).
[vi] Herrero, S., Millan-Leiva, A., Coll, S., Gonzalez-Martinez, R. M., Parenti, S., & Gonzalez-Cabrera, J. (2019). Identification of new viral variants specific to the honey bee mite Varroa destructor. Experimental and Applied Acarology, 79(2), 157-168.