Speculative biology
Abstract
We are all well aware that honey bees play a special role in life on planet Earth. Besides the well-beloved honey products, these insects are important as pollinators of a variety of crop plants, used for food by humanity. At the beginning of the second millennia, however, a large decline in the bee population raised serious concerns about the future of the planet. The current study explores several scenarios in the case of the complete extinction of honey bees.
Why do bees go extinct?
It is true that the occurrence of the so-called Colony collapse disorder among honey bees (especially Apis melifera) is becoming a global threat to food production. Although scientists do not have a conclusive answer to what is the cause of this phenomenon, a variety of causes can be easily underlined.
The extensive use of insecticides to combat herbivores along with other pesticides has led to the unwanted decline in the bee population due to toxicity. Apparently, with appropriate regulation and good timing of application, this problem could be partially solved.
A much more significant threat is the numerous pests, ranging from viruses and bacteria to fungi, unicellular parasites, and mites. Because the domestic honey bees are social animals, living in colonies, they are much more susceptible to parasitic diseases.
Finally, some purely genetic reasons could also lead to the decline of the species. A decrease in genetic diversity, caused by selection programs would eventually lead to lower adaptability and greater sensitivity to environmental factors, parasites, etc.
What would be the impact of bees’ extinction?
Obviously, the extinction of honey bees will be a slow process rather than an overnight event and will have a dramatic impact on life. However, it will not cause the “extinction of all human food”. First of all, the domestic honey bees are several species of approximately 20 000 bees species. As previously discussed, domestic honey bees are much more susceptible to diseases, and even in the worst scenario, we cannot assume that all bee species will go extinct at the same time.
There are no plant species that are exclusively pollinated by the domestic honey bee and most of them are also pollinated by other insect species (flies, moths, and beetles), as well as birds and other animals. However, the extinction of honey bees will probably lead to a decrease in pollination frequency and accordingly to yield, especially in some orchard trees such as apples, cherries, and related.
If no measures are taken, such plant species will gradually lose their importance in agriculture and will not be cultivated anymore, although it is not very probable they will go completely extinct. However, a scenario in which some of the last blooming trees, especially of the Prunus genus such as the famous Japanese cherries will become a rare touristic attraction, doomed to extinction is not to be underestimated.
It should be also noted that some of the most important crop plants are either wind-pollinated (like maize, wheat, and rice) or are predominantly propagated vegetatively (like potatoes). Therefore, we must assume that the complete extinction of all insect pollinators will cause a sharp decline of many plant species, but will not lead to the end of life on Earth. In fact, such mass extinction of insects will trigger significant evolutionary events.
Ecological compensation
Extinction of a large group of pollinators will lead to a chain of events, eventually leading to extinction or decrease in diversity of numerous other organismal groups. Accordingly, this will open some significant ecological gaps and opportunities for other organismal groups to fill them in compensatory events.
The rise of wind-pollinated plants
Considering the serious decline of insect-pollinated plant species, we must expect an increasing dominance of wind-pollinated plants. There are successful groups of anemophiles, such as the wide variety of grasses and some trees like oaks and alders. Some insect-pollinated plants might even evolve and become wind-pollinated. Generally, the co-evolution of plants and pollinators was a continuous process for over 100 million years and most entomophilous plants are so specialized they will not easily adapt to a new situation. This is largely because the structure of the flowers is quite different. Others, however, seemed to convert to wind pollination or exploit both strategies. Generally, a switch to wind pollination will require larger amounts of pollen and more accessible flowers, while the production of nectar and the color will not be needed anymore.
New pollinators needed
Known plant pollinators belong to a few Orders. These are mainly insects (butterflies, flies, bees, beetles), birds (hummingbirds, honeybirds, and sunbirds), and mammals (mainly bats, but also rodents, primates, and possums). Apparently, the ability to fly is a wanted, though not a compulsory feature of the potential pollinator.
The extinction of honey bees will open a significant ecological gap for competing pollinators. These will be mostly nectarivorous animals. Most possibly other insect species like flies and butterflies will increase in number, but the big question is whether there is another organismal group with the potential to fill the ecological niche.
Artificial solutions
The human bees
It may sound ridiculous, but some people are fully capable of adopting the cause to ensure the pollination of important plant species. This means that thousands of volunteers will need to collect pollen and transfer it using ear sticks or specially-designed equipment during the blooming season. This will correspond to the overall enthusiasm for a healthier and natural lifestyle in recent years. Such culture would evolve further into organizations, similar to sects, with their own holidays, festivals, and rituals. However, this could not be a permanent solution and the organizations for flower pollination will slowly decline in 30 to 40 years.
Pollinating drones
Actually, this idea is not quite new. Pollinating drones were proven to be very effective and could be developed into highly sophisticated machinery. A possibility to name is to construct autonomous drones with solar batteries (Fig. 1). They could offer several advantages over natural pollinators:
- Selectivity – while natural pollination is more or less an accidental event, drones could be programmed for targeted pollination. Thus, the purity of genotypes could be preserved, when needed, or specific cross-pollination in selection programs could be maintained.
- Improvement – pollination drones are not supposed to be limited to entomophiles. They could also collect pollen and pollinate anemophiles, such as some of the most important crop plants (g. wheat, rice, maize), significantly increasing the effectiveness of pollination and breeding programs.
- Defense – simultaneously with pollination, the drones could also identify or actively fight against pathogens and herbivores. For example, they can be used to remove aphids or spray fungicides,
- Research – the ability of drones to deliver samples to laboratories will offer the opportunity for much more effective monitoring of genetic diversity, viral spread, etc.
Figure 1. A possible concept for an autonomous pollination drone is highly influenced by the anatomy of an actual bee. 1 – cameras, used for identification of -target flowers; 2 – propellers; 3 – sun batteries; 4 – pesticide reservoir; 5 – pesticide sprayers; 6 – pollen collectors; 7 – sample collectors.
Developing self-pollinated varieties
The important role of bees and other pollinators is to transfer the pollen from one flower to another flower, which is compatible. Generally, fruit trees are self-incompatible, meaning that the pollen cannot successfully fertilize the female gametophyte of the same flower, of another flower on the same tree, or another tree, which is closely related. The genetic basis of self-incompatibility was extensively studied and the genes (S-genes), responsible for this were identified, meaning that through genetic engineering the self-incompatibility could be overcome.
In such a way, new, self-pollinated varieties could be developed, thus ensuring that the role of pollinators would diminish. The rate of pollination without bees will be much lower and the quality of fruits will be most possibly negatively affected, but still, research in this direction will be extensive.
Conclusions
A world without bees will be definitely a world, very different from what we are accustomed to. The extinction of a single species will be detrimental to many others, both plants and animals, but will also trigger evolutionary events. The impact on humanity will be also enormous, although not devastating and humanity itself will develop strategies to oppose this. Either in a negative way or not, the world will be changed.