Many of these places are already suffering, due to wars and pre-existing hunger. The blocking of the Strait of Hormuz has made fertiliser scarce just as many farmers need it for their next crop cycles (its reopening, announced on June 14th by Donald Trump, America’s president, is uncertain and comes too late). The European Commission has warned of humanitarian disasters in African countries including Chad, Somalia, South Sudan and Sudan, as well as Ecuador, Haiti and Venezuela. There are ways to blunt the impact: planting drought-tolerant seeds, for instance, or storing fodder and water for livestock. But the time to start is now. ■ Curious about the world? To enjoy our mind-expanding science coverage, sign up to Simply Science, our weekly subscriber-only newsletter. This article was downloaded by zlibrary from https://www.economist.com//science-and-technology/2026/06/16/the-coming-el-nino- could-be-the-strongest-ever-recorded

Science & technology | Sweet teeth The chocolate industry is built on the labour of bloodsucking midges Researchers have now confirmed how cacao plants are pollinated June 18th 2026 The world’s chocolate industry boasts revenues of more than $140bn. In recent years the market for cacao beans, the crucial ingredient, has often been tight. In April 2024, after poor harvests in West Africa, the price passed $10,000 per tonne for the first time. Although it has fallen back since, it remains significantly higher than earlier in the decade. A good time, then, for the world’s farmers to try to boost their harvests. One way would be to pollinate their existing plants more efficiently, so as to produce more of them in the next generation. There is a problem, though: no one has been quite sure how cocoa plants are pollinated. Now, though, work by Eliza Van de Sande, a PhD student at Vrije University in Brussels, and

published in Basic and Applied Ecology, suggests that a group of tiny blood- sucking midges are essential to the process. Many plants rely for pollination on an evolutionary bargain with animals. The plant produces high-energy nectar that entices animals (usually insects) to visit. But to get it, an animal must venture inside a flower. As it does it gets covered in pollen, while also shedding pollen stuck to it by other plants. Farmers often try to enhance the process by making their farms attractive to pollinating insects. The reason cacao pollinators have remained mysterious is mostly because of anatomy. Cacao flowers are very small, structurally complicated and hidden by hoods that make it tricky to see what is going on inside. To make matters worse, many of the visitors to cacao plants are minute fly species that are notoriously hard to identify. Ms Van de Sande and her colleagues observed insects visiting cacao flowers on farms in Malaysia and French Guiana. Rather than simply counting the visitors, as most previous studies had done, the team opened and inspected the flowers. Any insects inside were observed to work out whether they were interacting with the reproductive parts of the flower. The insects were then captured and checked to see if they were carrying cacao pollen. Ants, bees and midges all turned up inside the flowers. But of the 449 insects that the researchers collected, 439 were midges. Of those, 185 were biting midges that were often seen interacting with plant reproductive organs and were covered in cacao pollen about a third of the time. Few of the other bugs showed much evidence of doing anything for pollination. Those results strongly suggest that biting midges are the dominant force behind cacao pollination. They might therefore be a useful focus of efforts to enhance production. Ms Van de Sande and her colleagues also found that the midges were far more active when it was cool and humid. That could be bad news for cacao farmers, because—thanks to climate change—many of their plantations have been getting warmer and drier. Luckily, they have options. Ms Van de Sande points out that “agroforestry” techniques, in which native trees are grown on plantations to provide shade,

lower temperatures and increase humidity could be one way to encourage more pollinators to move in. Admittedly, trying to encourage more bloodsucking midges might be a hard sell for farmers themselves. But it might improve their yields. ■ Curious about the world? To enjoy our mind-expanding science coverage, sign up to Simply Science, our weekly subscriber-only newsletter. This article was downloaded by zlibrary from https://www.economist.com//science-and-technology/2026/06/17/the-chocolate- industry-is-built-on-the-labour-of-bloodsucking-midges

Science & technology | Leavesdropping How plants keep tabs on the competition They grow faster when their rivals are doing the same June 18th 2026 Given their slow growth and sessile lives, the idea of plants battling one another may seem fanciful. Yet they do. They fight for access to water, nutrients and pollinators. Since one plant’s leaves are another’s shade, growing towards the sun can be a duel to the death. As in any conflict, espionage helps. A paper published in the Journal of Experimental Botany reveals how plants engage in it. Botanists have known for years that plants can communicate with each other. One way is via chemicals known as volatile organic compounds (VOCs). When plants are attacked by pests, for instance, the composition of the VOCs they release changes. Previous work has shown that this drives nearby plants to raise their own defences in anticipation of being attacked in

turn. What has gone unexplored is whether plants detect VOCs released by their neighbours when they are healthy. So Velemir Ninkovic, an ecologist at the Swedish University of Agricultural Sciences, decided to run an experiment. With a team of colleagues, Dr Ninkovic planted three varieties of barley that grow at different rates—one quickly, one slowly and one at a middling pace. The plants were put in growing chambers next to one another, but with no way for them to shade their neighbours. The only connection that the plants had to one another was through one-way air vents that connected their growing containers. These allowed the researchers to blow air from one chamber to the next, and to monitor the effect that this had on the plants over 25 days. The results were striking. The slow-growing barley grew more quickly when it was exposed to air from the chambers of its fast-growing cousins, producing 20% more biomass than when it was placed next to slower- growing plants. This, Dr Ninkovic surmises, is because the slow-growing plants were detecting the compounds released by their neighbours and realising that, in the wild at least, they would be at risk of getting shaded out if they did not get a shift on. Fast-growing plants exposed to air from the chambers of their slow-growing cousins reacted in the opposite way. With less need to race for the sun, they cut their growth rates notably. (The plants with intermediate growth rates had no significant effects on their neighbours.) Dissection of these plants and genetic analysis of their tissues revealed more details about exactly what was going on. While the laggards were switching resources towards growth, the speedsters were able to spend more of theirs on metabolically expensive defensive measures, such as churning out chemicals that make their leaves unpalatable to herbivores. Barley plants, in other words, can chemically eavesdrop on their competitors, and tweak their own growing strategies accordingly. Farmers are already experimenting with using VOCs to boost productivity. Dr Ninkovic’s results suggest they may be able to nudge crops to produce protective compounds if pests are expected to arrive, as well as inducing them to grow more quickly to boost yields when risks are low. ■

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Science & technology | Well Informed A new drug targets one of cancer’s master switches The pancreatic-cancer drug could be the first of an entirely new class of treatments June 18th 2026 Scientists are not usually an excitable bunch. So when many thousands of them gave a standing ovation at a conference in Chicago, it meant something special had happened. The applause was for the results of clinical trials of a drug called daraxonrasib, developed by Revolution Medicines, a company based in California. It is designed to treat pancreatic cancer. The drug almost doubled median survival times from 6.7 months to 13.2 months. This victory over one of the most challenging cancers was an emotional moment for many.

The drug is not a cure. Cancers often develop resistance to targeted drugs such as daraxonrasib. Instead, its promise for patients is that, when used alongside other treatments, it might buy them months more life. Pancreatic cancers are aggressive and usually symptomless. They are mostly diagnosed after they have already spread around the body. Few patients survive longer than a year. Pancreatic cancers are also resistant toinhi immunotherapy, a class of treatment that encourages the body’s immune system to fight tumours, and which has had great success in many other areas of oncology. A mutation in a protein called KRAS, which drives most pancreatic cancers, creates an environment around the tumour that is hostile to immune cells. Daraxonrasib is expected to speed its way through approval in America. Although it was given in the trial to patients who had already tried chemotherapy, it seems likely to become a first-line treatment for the disease. The drug works by inhibiting KRAS. Other work suggests this also changes the environment around tumours in ways that might make them more susceptible to immunotherapy. If that theory proves correct, it could improve survival times still further. There is a bigger story. KRAS is a molecular switch in the cell that is heavily involved in cell division. It can be either off or on. A single mutation can leave it jammed on, endlessly signalling to cells that they should multiply—and endless growth is the defining pathology of cancer. Stopping KRAS might help in other sorts of tumour where the same mutation drives the disease. Candidates include some colorectal and lung cancers and, to a lesser degree, endometrial, small bowel and stomach cancers. What is more, KRAS is just one of a family of “oncogenes”—those often involved in cancers—that are collectively known as RAS mutations. Daraxonrasib could, in theory, work to some degree on other RAS-driven cancers such as multiple myeloma, a type of blood cancer. RAS mutations are found in 20% of all cancers, accounting for about 3.4m cases of cancer around the world every year. They have been a promising target since their discovery in 1982. But the structure of the proteins produced by the genes has few molecular chinks into which drugs might get their hooks. For four decades they were considered “undruggable”—but no longer.