"The battle between plants and insects increases the number of habitats in the rainforest," thus increasing the diversity of trees living there, says biology doctoral student Paul Fine, first author of the study published July 30 in the journal Science.
Study co-author Phyllis Coley, a biology professor at the University of Utah, says the research sheds light on the amazing diversity of species in tropical rainforests.
"Understanding diversity is a holy grail in ecology," Coley said. "Part of diversity is how many species you can pack into a given habitat, but part is how many different habitats exist that can harbor different species" an issue clarified by the study.
Fine and Coley conducted the study with Italo Mesones, a student at the National University of the Peruvian Amazon in Iquitos. The study was Fine's Utah doctoral thesis, which he completed while also working at Chicago's Field Museum of Natural History.
Some trees grow on red clay, others on white sand
In the Peruvian rainforest, many trees live on fertile red clay soil, while others live on nutrient-poor white sand soils. In the new study, the scientists transplanted red clay tree species onto white sand soil, and transplanted white sand tree species onto red clay soil. Net-covered enclosures were built around half the transplanted trees to protect them from insects. Other transplanted trees were left unprotected.
Trees that normally grow on red clay soil thrived when transplanted onto white sand soil but only if protected from hungry insects, which included grasshoppers, beetles, caterpillars and various sap-sucking insects such