If insect diversity were to disappear, a vital part of the system that supports us would be lost. Nature would change, and our diet would have to change with it. Pollinator robots would not be able to compensate for the absence of insects.
In early 2019, The Guardian, a British newspaper, anxiously wrote that the world’s insects might disappear within a century if their populations continue to shrink at current rates. But even though scientiﬁc studies conﬁrm the decline of insects, they will not disappear altogether. On the other hand, habitats, diversity and numbers are changing dramatically. If insects cease to perform many of the services they currently provide to nature and to humans, what would the world look like?
Most plants are reliant on insects because their ﬂowers are not self-pollinating, and their pollen is not carried by the wind. Without insects, global nutrition would be less varied. Insects transfer pollen from one ﬂower to another, and ensure the exchange of genetic material between plants of the same species. This enables the plants to produce seed and fruit, and over generations to adapt to a changing environment.
If pollen is transferred between fewer ﬂowers, plants that rely on pollination by insects develop fewer seeds and fruit. Harvests of maize, rice and wheat, the most important staple crops, are not at risk because their pollination does not depend on insects. But yields of many fruits and vegetables would suffer. These crops are an important source of vitamins and nutrients. Production of cherries could fall by 40 percent, and of almonds by 90 percent.
Some types of vegetables, such as cucumbers and pumpkins, might almost disappear. Around 6 percent of the total volume of cultivated plants would be lost, according to some estimates. Producers in Germany alone would lose around 1.3 billion euros a year. A development of this kind would further exacerbate the problem of ensuring an adequate and balanced diet for humanity worldwide.
Cross-pollination (by insects or the wind) stimulates many plants to produce greater quantities of certain vitamins and minerals. Without pollination by insects, the composition of nutrients in foods would change. This is especially worrying in developing countries, where people cannot simply take food supplements to obtain the missing nutrients as in industrialized countries.
To counteract this situation, plantings could be pollinated by hand, and robot bees could be used in polytunnels. Certain crops, such as apples, pumpkins, cherries and kiwis, are already being pollinated by hand in over 20 countries, including China, Korea, Pakistan and Japan, as well as Argentina, Chile, New Zealand and Italy. Some varieties of apples, pears and pumpkins set fruit without having to be pollinated by insects. This characteristic could be expanded through breeding and used widely to maintain harvests.
An unpollinated pear blossom that develops into a fruit has no seeds – a phenomenon called parthenocarpy. This commonly occurs through the mechanical stimulation of the carpel (the female reproductive part of the ﬂower). This and similar processes have disadvantages: a seedless apple contains less calcium and rots more quickly than one with seeds. In strawberries too, pollination by insects has a decisive inﬂuence on hormonal processes in the developing fruit – resulting in a better-tasting and longer-lasting fruit.
Greenhouses or polytunnels eliminate the wind, so tomatoes grown in them have to be “buzz pollinated”. Because they are effective pollinators, bees are often introduced into these structures. The bees vibrate their wings at a particular frequency, causing the tomato ﬂowers to release their pollen. Humans can use an electric toothbrush to imitate this effect. In an insect-free world, one where bumblebees have also fallen by the wayside, robot bees might be able to take over the buzz pollination.
That is not yet possible, but engineers are already working on technical solutions. The ecology of pollination differs markedly from one plant species to another, and building suitable robot bees for all of them will not be possible. Wild plants take on a wide range of forms and occur in stands of different mixed-species. Robots would have to learn to recognize each species and adapt their pollination mechanism to each one.
Technology is still a long way from replacing the complexity of ecological systems with artiﬁcial intelligence. Many ﬂowering species in meadows rely on insect pollination; without their six-legged friends, there would simply be no more species-rich ﬂowering meadows. Meadows and pastures would consist only of self-pollinating and wind-pollinated grasses.
Grazing would also be much more difﬁcult. Along with earthworms and microorganisms, insect larvae help prevent erosion by stabilizing the soil. Without them, cattle would slip and slide around in wet weather. Insects are also indispensable in decomposing manure.
Without specialist dung beetles, the ground would be littered with ageing cowpats. This ecological problem has already occurred once before: at the start of the 19th century, when cattle were introduced to Australia, there were no native dung beetles. It was only after they were imported that the problem was solved.