The Effects of Caffeine on Mealworms

Caffeine is a naturally-occurring alkaline substance that occurs in plants. While it's commonly known as a quick source of energy for humans--drinks like tea and coffee contain quantities of caffeine--in nature, it actually acts as a defense mechanism for some plants. Plants produce caffeine to paralyze or kill insects that feed on their leaves or stems. In order to understand the effect of caffeine in nature, scientists study the metabolic reactions when caffeine is consumed by insects like mealworms.

Death

• Extreme doses of caffeine can cause death of mealworms, as their systems will be unable to process and remove the stimulant. Doses of moderate levels of caffeine may cause some mealworms in an experimental group to die, while others less susceptible to the drug will survive.

Developmental Impact

• Mealworms are the larvae stage of a type of beetle. The introduction of caffeine into the meal worm's diet can affect how quickly they progress through this developmental stage. Generally, mealworms with a high-caffeine diet take longer to enter a metamorphosis than a control group of worms.

Activity Levels

• This will come as no surprise to anyone used to a cup of coffee to start the day, but caffeine increases the activity level of mealworms. Both the metabolic rate (the rate at which food is broken down and consumed by an organism) and movements of the mealworms increase. But this added activity comes at a heavy cost. Generally, mealworms that are more active also have shorter life spans than their less-manic counterparts.

Size

• Though the link between caffeine and growth is tenuous in humans, mealworm experiments demonstrate that caffeine consumption can act to stunt growth. Mealworms fed on a diet of caffeine generally are smaller than usual, with less body weight.