Insects have long been a subject of interest since many exhibit social behaviors similar to humans and even have social statuses within their colonies. Apart from that, insects such as bees also make use of fascinating techniques to communicate information with its fellow workers.

Such industrial behavior of insects continue to interest not just scientists but people in general, that bees and ants have even been considered as model workers that children should emulate to better contribute to the growing society. A recent study, however, discovered that ants actually encourage more workers to stay inactive, especially when the colony is large.

Researchers from the Missouri University of Science and Technology published the findings of their study on the energy consumption of ants titled "Heterogeneous activity causes a nonlinear increase in the group energy use of ant workers isolated from queen and brood" in the journal of Insect Science.

According to the study, as an ant colony becomes larger, so does the percentage of ants that remain inactive in an effort to conserve energy and resources.

The Puzzle

Scientists have known for a while that larger colonies tend to spend less energy than smaller ones, but the reason for this remained a mystery until Dr. Chen Hou, assistant professor of biological sciences at Missouri University of S&T and his team of scientists observed several colonies of varying sizes to find the answer.

"It has been a long-standing question in the field as to why large colonies of ants use less per-capita energy than small colonies [...] Both humans and ants face similar problems of allocating resources based on tasks and energy. Understanding how ants spend their energy in relation to their group and why they do so will provide insight [...]," Dr. Hou says.

Ant Work-Life Balance

Hou's team used an advanced computerized vision analysis program developed by his colleague and research team members, Dr. Zhaozheng Yin and Daniel C. St. Clair, to observe ants over a longer period of time and at a higher temporal resolution than previous studies.

Using the data the program collected, the team discovered that walking ants used five times more energy than that of ants standing still.

In a colony consisting of 300 ants, 80 percent of the members were inactive while the 30-member colony had 60 percent inactive members.

The team suggests that the inactivity has to do with conservation of energy and resources. That is, if more ants work, there will be more resources foraged but the colony would also require a larger resource because more energy is expended. The current system in which a big percentage of ants stay inactive would mean that a colony would have a smaller resource, but since a large number of ants don't consume energy, they also don't need to partake in the limited resource.

"It is intuitive that colonies have inactive members, because these members may serve a backup role or buffer, which would be activated when colonies are under stress, such as an urgent need for nest maintenance or defense," Hou says.

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