Study: Smelling Sense is Similar in Humans, Insects

Locusts farmed for human consumption are seen at the Kreca breeding facility in Ermelo, the Netherlands. Reuters
Locusts farmed for human consumption are seen at the Kreca breeding facility in Ermelo, the Netherlands. Reuters
TT
20

Study: Smelling Sense is Similar in Humans, Insects

Locusts farmed for human consumption are seen at the Kreca breeding facility in Ermelo, the Netherlands. Reuters
Locusts farmed for human consumption are seen at the Kreca breeding facility in Ermelo, the Netherlands. Reuters

A research team from the Norwegian University of Science and Technology (NTNU) found that the process of "olfactory information" is similar in humans and insects.

By using the brain of a cotton bollworm as a model, the branching patterns and coding mechanisms the researchers detected in the small model brain seem to be relevant not only for insects, but also for mammals—which include people. The findings were published in the journal eLife on October 10.

"We find striking similarities in the structure and function of the olfactory system across different organisms. The similarities are probably related to the fact that the olfactory system is evolutionarily the oldest of all sensory systems," said Xi Chu, a researcher in Chemosensory Laboratory at NTNU and senior author on the study.

The researchers studied second-order olfactory neurons in male cotton bollworms. The males carry signals from the primary olfactory center to other areas of the brain, where the signals are further interpreted to provide the correct responses. They're strangely similar to neurons, called mitral cells, in humans and other mammals.

"When we smell something, it's because certain molecules that are dispersed in the air first activate sensory neurons in the olfactory epithelium. This is an area in the nose that captures odor molecules and carries them further into the brain's primary olfactory center. Here, the sensory terminals form a kind of map, so neurons that have the same type of olfactory receptor accumulate within spherical structures called glomeruli," Chu explained.

"Insects have a similar system of sensory olfactory neurons that form glomeruli in their antennal lobes. The similarity also applies to second-order olfactory neurons that send signals from the primary olfactory center to higher-order areas," he added.

The various odors are represented in the form of a collection of non-overlapping glomeruli in the primary olfactory center. But they are arranged in a quite different way in the subsequent second-order centers. In both insects and humans, the terminals of second-order olfactory neurons cover relatively large areas that partly overlap, he explained.



Pamplona Holds Opening Bull Run during San Fermín Festival

Participants run ahead of bulls during the first "encierro" (bull-run) of the San Fermin festival in Pamplona, northern Spain, on July 7, 2025. (Photo by JORGE GUERRERO / AFP)
Participants run ahead of bulls during the first "encierro" (bull-run) of the San Fermin festival in Pamplona, northern Spain, on July 7, 2025. (Photo by JORGE GUERRERO / AFP)
TT
20

Pamplona Holds Opening Bull Run during San Fermín Festival

Participants run ahead of bulls during the first "encierro" (bull-run) of the San Fermin festival in Pamplona, northern Spain, on July 7, 2025. (Photo by JORGE GUERRERO / AFP)
Participants run ahead of bulls during the first "encierro" (bull-run) of the San Fermin festival in Pamplona, northern Spain, on July 7, 2025. (Photo by JORGE GUERRERO / AFP)

Thousands of daredevils ran, skidded and tumbled out of the way of six charging bulls at the opening run of the San Fermín festival Monday.

It was the first of nine morning runs during the famous celebrations held in the northern Spanish city of Pamplona.

The bulls pounded along the twisting cobblestone streets after being led by six steers. Up to 4,000 runners take part in each bull run, which takes place over 846 meters (2,775 feet) and can last three to four minutes.

Most runners wear the traditional garb of white trousers and shirt with red sash and neckerchief. The expert Spanish runners try to sprint just in front of the bull's horns for a few death-defying seconds while egging the animal on with a rolled newspaper.

Thousands of spectators watch from balconies and wooden barricades along the course. Millions more follow the visceral spectacle on live television.

Unofficial records say at least 15 people have died in the bull runs over the past century. The deadliest day on record was July 13, 1980, when four runners were killed by two bulls. The last death was in 2009.

The rest of each day is for eating, drinking, dancing and cultural entertainment, including bull fights where the animals that run in the morning are slain in the bull ring by professional matadors each afternoon.

The festival was made internationally famous by Ernest Hemingway’s classic 1926 novel “The Sun Also Rises” about American bohemians wasting away in Europe.