Chloé Rosa-Teijeiro leans over a tray filled with saline, her hands steady as she lifts a sliver of chitin from a yellow mealworm beetle no longer than a grain of rice. Inside, the delicate organs float like tiny jewels—Malpighian tubules like fine threads, a golden digestive tract, a soft white mass of fat body. This is the first time anyone has seen the full internal anatomy of Tenebrio molitor in such detail, and it could change the future of sustainable protein farming.
With global demand for meat rising and livestock farming straining the planet’s resources, insects like the yellow mealworm offer a promising alternative. Packed with protein and approved for human consumption in the EU, they require far less land, water, and feed than cattle or poultry. But farming them at scale has been held back by a hidden threat: disease. Densovirus outbreaks have wiped out entire colonies, and until now, farmers had no way to detect illness early—because no one knew what a healthy mealworm’s insides should look like.
That’s where the team at Université de Montréal stepped in. Led by veterinary pathologist Marie-Odile Benoit-Biancamano, with Chloé Rosa-Teijeiro and Fanny Renois, they developed the first standardized dissection protocol for adult yellow mealworms. The breakthrough? Dissecting the insects submerged in saline, mimicking the natural environment of their hemolymph, or insect blood. This keeps tissues intact, prevents drying, and allows for clear, repeatable observations under the microscope. After two months of meticulous work, the team published their findings in the Journal of Veterinary Diagnostic Investigation, complete with annotated images of both male and female anatomy.
What they discovered was surprising. In males, the testes form a flowerlike structure with six follicles and two previously undocumented accessory glands. In females, the spermathecal gland—responsible for nourishing stored sperm—is larger than the sperm storage organ itself, a rare trait that may boost reproductive success. But perhaps the most urgent finding came by accident: even beetles that looked healthy under standard conditions showed signs of infection. Histological analysis revealed granulomas, viral inclusions, and parasite eggs in the Malpighian tubules, fat body, and nervous system.
"We thought the colony was healthy, but that wasn’t exactly the case," Benoit-Biancamano said. That revelation underscores the power of this new tool—not just for science, but for farmers. With a clear anatomical reference, outbreaks can be caught earlier, biosecurity improved, and safer insect protein brought to market. The method uses standard lab equipment, making it accessible, though mastering it takes patience and precision. As Rosa-Teijeiro put it: "It’s like lifting the lid off an extremely fragile box."
Now, the team is turning to the next challenge: mapping diseased specimens. One tiny beetle at a time, they’re building the foundation for a cleaner, greener food system.