A caterpillar experiment revealed global insect predation patterns with the help of fake caterpillars. Results of the study showed, not just the predation patterns among insects in various locations across the equator, but also the responsible predators for the trend.
Fake Caterpillar Study
Caterpillars have been found to be quite useful in recent discoveries, but a new study is opting not to use the real thing. A study that was completed with the help of a collaboration between various universities including Oxford University and University of Helsinki in Finland, sheds further light into insect predation activity in areas that are more biologically diverse as well as areas that are not.
What the international team of 40 scientists did was to deploy 2,879 artificial caterpillars in an 11,660-kilometer gradient from the Arctic Circle to Australia. This seemingly strange experiment of leaving fake caterpillars was designed to tempt caterpillar predators into taking a bite out of the decoy, thereby revealing their natural feeding patterns.
The decoys were left in their positions for up to 18 days with the scientists checking in to see whether any predator has taken a bite.
What the researchers found was a pattern of how the world's insects feed on their prey as the decoys that were placed in locations closer to the equator, such as Southeast Asia, showed a much higher chance of being eaten compared to decoys placed in locations farther from the equator.
Though locations with warmer temperatures tend to have a larger biodiversity, results of the study showed a clear pattern that is mirrored on both sides of the equator as well as across elevation levels.
Specifically, they found that the daily chances of being eaten decreased by 2.7 percent for every latitudinal degree away from the equator. Upon checking whether changes in elevation also had an effect on predatory patterns, they also found a 6.6 percent decrease in chances of being eaten with every 100-meter elevation increase.
Essentially, the odds of a caterpillar being eaten increase in locations nearer to the equator and at lower elevations.
Another interesting find of the study points to exactly what type of predator is responsible for most of the bite marks. Though birds and mammals are often seen as the main predators in tropical regions, this particular study showed that arthropods such as ants are the caterpillars' main predators as many of the decoys showed bite marks that are consistent with arthropod bites instead of beak or mammal bite marks.
Results of the study were published in the journal Science, stamping a clear predatory pattern and revealing arthropods as a major driving force in tropical predatory trends.
Authors of the study are hoping that their research provides a significant foundation in understanding the patterns of global ecosystem, and how global biodiversity may change along with changes in the environment.