Science Diary: Caterpillars – Interactions

Invisible Web of the Rainforest

LD: “When we first found out that if we change the interactions inside this one species of plant, that it would effect plant diversity in the rainforest, we didn’t believe the results.”

JM: In a rainforest ecosystem, the relationships between plants and animals are often complex and interdependent. Change one seemingly small thing, and you could easily upset the entire ecosystem. Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside. Lee Dyer is an ecological entomologist at the University of Nevada in Reno, who studies the rainforests of Costa Rica.

LD: “This pepper plant that has a web of interactions within it, alright, so there’s the plant itself, and then there’s these little caterpillars that can actually kill the plant. And then there are these ants that live inside the plant that kill the caterpillars. And then there’s a beetle that kills the ants. The experiments that we did, for the most part involved adding beetles to patches of plants where these beetles didn’t exist. When we did that what happened is they suppressed populations of ants, which normally suppress the caterpillars. So with the ants gone, caterpillar populations exploded and the leaf biomass declined really quickly of this plant. And what happened in this case is that other caterpillars were also released from control by the ants and they ate other species of plants, including plants that were destined to be big trees. They were seedlings of these plants that are normally these huge 40-meter tall trees that extend out from the canopy of the rainforest. The end result was that several years of just barely increasing the population of these beetles changed the diversity of plants in the understory.”

JM: We’ll hear more about the ecology of the rainforest in future programs. You can hear this and previous programs on our podcast. Pulse of the Planet’s Science Diaries are made possible by the National Science Foundation. I’m Jim Metzner.

Science Diary: Caterpillars - Interactions

Tinker with the micro-ecology of just one plant, and you risk altering an entire ecosystem.
Air Date:10/07/2008
Scientist:
Transcript:

Invisible Web of the Rainforest

LD: "When we first found out that if we change the interactions inside this one species of plant, that it would effect plant diversity in the rainforest, we didn't believe the results."

JM: In a rainforest ecosystem, the relationships between plants and animals are often complex and interdependent. Change one seemingly small thing, and you could easily upset the entire ecosystem. Welcome to Pulse of the Planet's Science Diaries, a glimpse of the world of science from the inside. Lee Dyer is an ecological entomologist at the University of Nevada in Reno, who studies the rainforests of Costa Rica.

LD: "This pepper plant that has a web of interactions within it, alright, so there's the plant itself, and then there's these little caterpillars that can actually kill the plant. And then there are these ants that live inside the plant that kill the caterpillars. And then there's a beetle that kills the ants. The experiments that we did, for the most part involved adding beetles to patches of plants where these beetles didn't exist. When we did that what happened is they suppressed populations of ants, which normally suppress the caterpillars. So with the ants gone, caterpillar populations exploded and the leaf biomass declined really quickly of this plant. And what happened in this case is that other caterpillars were also released from control by the ants and they ate other species of plants, including plants that were destined to be big trees. They were seedlings of these plants that are normally these huge 40-meter tall trees that extend out from the canopy of the rainforest. The end result was that several years of just barely increasing the population of these beetles changed the diversity of plants in the understory."

JM: We'll hear more about the ecology of the rainforest in future programs. You can hear this and previous programs on our podcast. Pulse of the Planet's Science Diaries are made possible by the National Science Foundation. I'm Jim Metzner.