Measuring sleep in insects is not an easy task. In many species there are periods of apparent inactivity , but do they sleep like us? A study carried out by the University of Pennsylvania and the California Institute of Neurosciences has revealed that fruit flies do it in such a profound way that, when they are at rest, it is quite difficult to wake them up. Also, if they don’t get enough rest, they show clear symptoms of lack of sleep , and they react the same way people do to caffeine or sleeping pills.
In fact, there is an insect that has a high tolerance to caffeine : it is the coffee borer, Hypothenemus hampei , a tiny beetle that lives in the berries of the plant, where pure caffeine is found at concentrations lethal for most of insects and many other animals. If you were a human, your coffee consumption would be the equivalent of drinking more than 200 espresso a day. The secret of this insect is that it has up to 14 types of bacteria in its guts, which help it tolerate such high doses of caffeine. One of them is Pseudomonas fulva . This bacterium has a gene responsible for it being able to break down caffeine so easily and survive solely on it.
As with humans, effective communication between members of a society is essential for maintaining life in community. That is why night rest is so important also for one type of insect: bees.
They, for their part, are not able to communicate effectively with their peers if they have not been able to take a nap. When the flowers close at night, they sleep with their jaws closed around a stem or twig , which prevents them from falling to the ground. Communication between bees is done in a very sophisticated way. Through a kind of dance, or stimuli such as the smell of pheromones, they inform the individuals of their society where to find food.
Therefore, a “badly rested” bee could spell disaster for collective life and the prosperity of the hive. Life in the hive is very demanding for bees ; drones, for example, are expelled or starved when they are no longer needed (at the end of the reproductive period of virgin queens). On the other hand, worker bees choose larvae less than three days old when they begin to observe that a queen bee is being inefficient.
However, there are thousands of types of bees. Some of them live in community, but others live alone. Those that live in society form colonies of between 15,000 and 80,000 individuals.
Insects are the most abundant type of living being on Earth. In fact, the entire surface of the Earth is covered by insects, except Antarctica, and it is estimated that there are about 10 billion insects per square kilometer on the Earth’s surface. However, despite their abundance, there are still many data on insects that we do not know.
