Scientists made an interesting experiment to analyze global predation patterns. They glued fake caterpillars onto plants to see how often they get bitten. The study, published in the journal Science, was meant to show how predation rates vary in different places of the world, and which animals attempted to eat the clay insects.
Looking at the global predation patterns
Any lizard, beetle, bird, and ant that attacked the caterpillars left bites or scratch marks on them. Then, researchers analyzed the marks in a lab in Finland to see who they belonged to and how at risk were the fake insects. Thus, they observed that caterpillars from the equator are 8 times more likely to get eaten compared to the ones living closer to the poles.
This is not the first time scientists used fake caterpillars to study predation incidence in certain areas. Tomas Roslin from the Swedish University of Agricultural Sciences used the same method to how animals exhibit this behavior in Greenland. However, he did not have much luck.
When he talked to other researchers who used the technique, they said it worked. Then they observed that it was a great difference between the places where the dummies were placed. Tomas Roslin places the in Greenland, while another colleague put them in the rainforests in Borneo.
Equator caterpillars get eaten more often than those in colder regions
Therefore, scientists decided to place fake caterpillars in several places around the world to study the global predation patterns. Several scientists from all over the world participated to the experiment and placed clay caterpillars in different regions.
“We’ve known for a really long time that there are more species in the tropics than there are in polar regions. But we don’t have as good of an idea of the geography of interactions between species,” mentioned Will Petry, one of the researchers.
After the caterpillars were recovered, they were carefully placed into individual tubes and sent to the lab in Finland. This is how researchers discovered that predation was more intense in areas near the equator. The number of predators is much bigger there than at the poles, for instance, so more caterpillars get eaten.
Image source: Wikipedia