Entomologist Marcel Dicke retires: “Insects are truly fascinating creatures”

Did you know that we unknowingly consume around 500 grams of insects every year? Traces of ground-up insects can be found in processed foods such as peanut butter and tomato soup. But Dicke believes that eating insects deliberately has many benefits: “They’re healthy, packed with proteins and minerals, and offer a solution to feeding the growing global population with more sustainable animal proteins. Current meat production methods are largely unsustainable and insufficient. In Europe and North America, we consume far more animal protein than is good for both ourselves and the planet. Around 70% of all farmland is currently used for meat production, mostly to grow animal feed. This is inefficient and contributes significantly to climate change.”

In contrast, producing insects as a source of animal protein is much more sustainable. Insects require only a fraction of the space and resources compared to livestock such as cattle and pigs. For instance, fly larvae can be reared on by-products from the food sector. Moreover, insect farming generates far lower greenhouse gas emissions per kilogram of product than traditional meat production. Even their waste is valuable. “The droppings and shed skins of insects are rich in nitrogen and improve soil quality,” Dicke explains. “They enhance the soil’s microbial composition, promote plant growth and pollination, and make crops more resistant to diseases and pests. By integrating insects into our food system, we can make it more sustainable through a circular approach.” According to Dicke, this offers a promising pathway to a future where sustainability and food security go hand in hand.

Insects are indispensable

Marcel Dicke grew up at the outskirts of Rotterdam, where he spent his childhood exploring nature in search of plants and animals. His interest in biology was sparked at high school, and during his university studies his fascination with insects and their role in ecosystems grew deeper. “Insects are everywhere,” says Dicke. “They make up the majority of Earth’s biodiversity. They pollinate flowers, recycle organic waste, and 80% of bird species rely on insects for food.” With evident enthusiasm, he adds, “Take parasitoid wasps, for example. These insects are widely used in sustainable crop protection. The females lay their eggs in or on pest insects. The larvae that hatch then consume the pests. And here’s the fascinating part: the female can decide whether her offspring will be male or female. A fertilised egg becomes a daughter, while an unfertilised egg develops into a son.”

From aversion to acceptance

Not everyone shares Dicke’s enthusiasm for insects, particularly when it comes to eating them. “People in the Netherlands aren’t used to seeing insects on their plates,” he admits. “But that’s actually quite strange, as insects were part of the diet here not so long ago. In France and Germany, for instance, maybeetle soup – reminiscent of lobster bisque – was served until the mid-19th century. Today, many people find the idea unappealing, but fried dragonfly larvae with mint, for example, are absolutely delicious.”

For insects to play a serious role in the food chain, more than just a shift in consumer behaviour is required. The agricultural system also needs to be restructured. Dicke notes that the industry is still in its infancy. “The production costs of insects for animal feed are currently comparable to fishmeal but higher than soy. Innovations and scaling up production could help bring these costs down.”

A scenario study Dicke conducted with Chinese researchers shows that replacing soy with insects as a protein source could make food production in a large country like China climate-neutral. “Political factors, such as the authorisation of insects as food, also play a crucial role,” he adds. “The European Food Safety Authority (EFSA) has now approved mealworms and crickets for human consumption. I’m pleased to see progress, but there’s still a long way to go.”

Encouraging society to embrace insects as food requires further research into various aspects, Dicke argues. At Wageningen University & Research, researchers from different disciplines collaborate to tackle this challenge. Many factors must be considered: sustainability, health, animal welfare (for both farm animals and insects), economic feasibility, and, of course, taste. “Bringing all these aspects together is essential for understanding how to incorporate insects into a sustainable food chain.”

Progress is being made, Dicke notes. “You might not see whole insects in supermarkets yet, but they can be incorporated into food products. That’s probably the best way to help people become accustomed to them.”

Plants cry for help

After studying at Leiden University, Marcel Dicke moved to Wageningen to research chemical ecology - the role of odours in interactions between mites and plants. During his PhD research, he made a groundbreaking discovery: plants “cry for help” when attacked by herbivorous spider mites. Bean plants, for example, release a complex blend of scents that attract predatory mites - the natural enemies of spider mites. Dicke was the first to publish this finding, but the scientific community was initially sceptical. “People didn’t believe plants could do such a thing,” he recalls. But he wasn’t deterred. “I kept answering colleagues’ questions and conducting new experiments. The results were clear: plants can indeed cry for help. That process of addressing scepticism through research honed my skills as a scientist. When people doubt something, I work even harder to prove what’s possible.”

Marcel Dicke looks back on his career with gratitude, reflecting on the fruitful collaborations he’s had with many colleagues. “Collaboration is the foundation of good science,” he emphasises. For 22 years, he led Wageningen’s Laboratory of Entomology. A career highlight was receiving the prestigious Spinoza Prize in 2007 for his research on plant-insect interactions. “That recognition is an honour, but for me, it’s even more important to pass on my knowledge to younger researchers.”

Sharing knowledge and inspiring wonder

Even after his retirement, Dicke plans to continue teaching. “I want to share my enthusiasm and sense of wonder. When I show students a photo of the black soldier fly, I point out the intricate colour patterns in its eyes. I hope to spark their interest in this beautiful and important field. He concludes with an inspiring message for the next generation of researchers. “Follow your passion. That’s essential, especially in these polarised times when science is under pressure, for instance due to budget cuts. Keep believing in the future and stay committed. Don’t let people who say something is impossible discourage you. As Nelson Mandela beautifully said: Everything seems impossible until it’s done.”