The coffee plant uses caffeine as a defense mechanism, being toxic to most insects. But not for the coffee berry borer whose extreme tolerance toward the alkaloid makes it the most devastating plague of coffee.
Caffeine is the psychoactive substance most consumed in the world. The caffeine content of coffee varies depending on how you prepare it and mainly on the type of grain, even within the same plant can vary their concentration. In general, an espresso (30 ml) has about 40 mg of caffeine, while a Starbucks’ Venti (about 600 ml) has more than 400 mg. There are sources suggesting that larger amounts of caffeine are safe most healthy adults.
Effects of caffeine depend on the person concerned: those who drink coffee daily can tolerate much greater amount than do occasionally. But ingesting too much caffeine can cause a lot of symptoms, most related to the brain and the digestive system. In fact, someone can die from an overdose of caffeine, but quiet, for that it is necessary to take more than 100 coffees a day.
There is an insect that laughs at your tolerance to caffeine. It is known as the coffee berry borer and its scientific name is Hypothenemus hampei. This beetle is the most caffeine addict creature that exists and lives so quiet in the berries of the coffee plant, where there is pure caffeine at lethal concentrations to most insects and many other animals. If they were human for a moment, it would be equivalent to taking more than 200 express a day, but this bug does it every day and every hour.
The trick to survive this lifestyle is in their own guts, where up to 14 types of bacteria exist, being Pseudomonas fulva the most common. This bacterium has a gen responsible to degrade as easily caffeine and survive only with it.
These beetles, because of its size (0.2 to 0.6 mm in diameter) do not seem a great menace but it is the most serious pest of coffee in the world, creating huge problems for producers. They are making tunnels in the fruit of the coffee plant and laying eggs. The life cycle of these insects lasts 24 to 45 days, and it can be founded over three generations at the same plant.
Researches about pests could help find a way to control this insect, not attacking it directly with pesticides, but pointing to their intestinal microbiota, for example, developing a method that alters its bacteria so that caffeine to be toxic as it is for other insects.