About This Project

Parasitoid diversity is rapidly declining in La Selva Costa Rica, yet many species remain undescribed limiting our ability to understand how local extinction of parasitoids will impact ecosystem function and stability. Here, we explore the hypothesis that increased frequency of extreme weather events negatively affects tropical plant-insect-parasitoid interactions by measuring the impact of flooding on parasitism rates and interaction diversity.

Ask the Scientists

What is the context of this research?

We have over 20-years of data cataloguing interaction diversity among tropical host plant, lepidopteran herbivore and parasitoid species. We are concerned because our most recent analyses indicate staggering declines in parasitism rates and parasitoid diversity in Costa Rica. The time period in which we see this decline, we also see increased frequency of extreme precipitation events. We hypothesize that the change in climate in tropical ecosystems is resulting in declines in parasitism rates and parasitoid species diversity (Stireman et al. 2005). To test this, we need to expand our existing inventory of plant-caterpillar-parasitoid interactions at our two tropical sites: Yanayacu Biological Station in Ecuador and La Selva Biological Station in Costa Rica.

What is the significance of this project?

Parasitoid diversity is rapidly declining in La Selva Costa Rica. Amidst the fact that more than half of all described terrestrial organisms are involved in plant-insect-parasitoid interactions, data cataloguing tropical parasitoid species is scarce. Most specimens to date are singleton observations which do not provide enough data to calculate diversity and cataloguing interaction diversity requires the labor and time intensive task of collecting and rearing caterpillars for parasitoids. Thus, long-term data collected in this study will enable us to assess the impact of extreme weather events on ecological services and ecosystem stability provided by parasitoids. This will guide predictions on the impact of global climate change on ecological communities.

What are the goals of the project?

We will begin collection February 14th at La Selva and continue to collect samples through the year at both sites with the help of our field techs: Humberto and Wilmer. We will collect larval parasitoids from the lepidopteran hosts and adult parasitoids using malaise traps to document as many new and rare species of parasitic Hymenoptera and Diptera. We will sample various life history stages to understand population dynamics. Lastly, we will determine gene flow of focal parasitoids from natural forests to surrounding agriculture to help quantify loss of ecosystem services associated with loss of biodiversity. Our long term goal includes augmenting a one-of-a-kind dataset on tropical insect interactions so that we may continue to explore patterns of biodiversity.