Proposal: Diversity and Abundance of Natural Enemies: Parasitic Wasps in Urban Forest Fragments

Transcription

1 Proposal: Diversity and Abundance of Natural Enemies: Parasitic Wasps in Urban Forest Fragments Introduction: Biodiversity is fundamental to the sustainability and health of ecosystems. Native insects, for example, play a vital role in ecosystem services in many ways. Natural enemies, in particular (in the form of parasitoids), effectively hinder pest outbreaks and control populations. Natural enemies have saved an estimated $80 billion and $10 billion worldwide in crop and forest damages, respectively (Cracraft & Grifo, 1999). A very diverse and important group of natural enemies are parasitic wasps (Hymenoptera) those of which are vital to the control of pest species in crop and forest systems. These wasps will typically lay their eggs in or on an arthropod host and as the eggs hatch and grow they use their hosts for sustenance (Bonet, 2008). This process reduces the hosts' population size, helping to maintain a healthy and manageable population of the host species (Welsh, 2012). Adult parasitic wasps can also play a major role in parasitizing pest species that feed on and devastate local flora (Royal Entomological Society, 2014). Literature Review: A study by Lassau and Hochuli showed that the greater the complexity of the habitat, the greater the diversity of parasitic wasps. A study by Arnon et al, focused on the order Hymenoptera in old growth forests, and reinforced the study by Lassau and Hochuli, through disturbance having a higher diversity of parasitic wasps. Furthermore, a study by Hilszczanski et al, focused on parasitoids of saproxylic beetles in boreal spruce forests shows that altitude, slope and exposure have an effect on the diversity of parasitic wasps of saproxylic beetles. Current 1

2 literature focuses on the diversity and abundance of the entire order of Hymenoptera, parasitic wasps on specific prey species or in specific forest types such as old growth forests or boreal forests. Hypothesis: Parasitic wasps will have a greater diversity and abundance in habitats with higher disturbance and complexity. The main goal of this research is to measure the diversity and abundance of parasitic wasps, within urban forest fragments located in northern Delaware and southern Pennsylvania. Parasitoids are one of the most numerous and ecologically diverse groups of insects in temperate regions (Hilszczanski et al., 2005). Furthermore, this data will be used to correlate the diversity and abundance to covariates such as surrounding land use, rainfall, and non native flora. Data: In order to conduct this research data will be needed on the FRAME sites selected for specimen collection, including rainfall, non-native flora and surrounding land use. Other data that will be required is for the specimens. Specifically the number of parasitic wasps as well as their families. The data on the FRAME sites, rainfall, non-native flora and surrounding land use, is already available in digital form. However, the data for the specimens is not in digital form. This data will be structured as rasters. 2

3 Methods and Materials: Collection Techniques: In order to obtain the specimens to measure the diversity of the parasitic wasps within forest fragments, specimens will be collected throughout the summer field season. A total of 14 sites have been chosen from the departmental-wide FRAME (Forest Fragments in Managed Ecosystems) project, which monitors urban and suburban forest fragments on a long-term basis in order to identify key components involved with maintaining high biodiversity. FRAME sites are set in a grid of points at 25 meter intervals (except for one site gridded at 50 meter intervals). At each site three bowl traps of differing colors (white, blue and yellow) will be set at five chosen points, for a total of 225 bowls. The bowl traps will be 3.25 ounces and separately colored blue, yellow, or white which attracts the parasitic wasps. Each bowl trap will be filled with a solution consisting of propylene glycol, bleach, and dawn soap, to preserve the specimens. Each site will be sampled every two weeks from the end of March through mid September Specimens will be collected and the bowl traps refilled with the solution upon each visit. The collected specimens will be sorted, pinned, and identified to family. Statistical Analyses: Collected data will be analyzed using diversity indices to quantify the diversity of each family of parasitic wasp at each site. Further analyses will be completed using the statistical software R to correlate the data with surrounding landscape usage, rainfall and non native flora. Once this data has been correlated it will be mapped and expressed using Geographic Information Systems. 3

4 Expected Results: The results of this project will identify abundance and diversity of parasitic wasps in urban deciduous forest fragments. The results will also identify whether the surrounding landscape/land use, rainfall, and non native flora have an effect on the abundance and/or diversity of parasitic wasps in urban forest fragments. Policy Applications: This research will help in determining good habitat for parasitic wasps to help incorporate them into integrated pest management programs (IPMs). Timeline: The field work for this research will begin at the end of March and continue through September (when the parasitic wasps are active). Specific sites will be visited in a rotational order to ensure a sampling period every two weeks. When not collecting specimens in the field, the lab will be utilized for processing specimens and identifying to family. Once all the specimens have been collected, pinned and cataloged, the data will be analyzed using diversity indices and correlated with surrounding landscape, rainfall, and non-native flora of the chosen FRAME locations. Finally, the data will be correlated and mapped using GIS. Timeframe: June 9 - August 14: Summer Scholars: Collection and Identification September: Finish collecting, begin data analyses Mid October: Meet with Thesis Director to discuss preliminary results November 1: Complete "Introduction" and submit to Thesis director for review November 26: Begin mapping results using GIS December 13: Complete "Methods and Materials" and submit to Thesis director for review February 15: Complete "Results" and submit to Thesis director for review 4

5 March 20: Complete "Discussion" and submit to Thesis director for review April 10: Complete revisions for all sections and submit full draft for review May 5: Finish all revisions Budget: Most of the expenses for this research will consist of vials, ethanol, bowls, pins, label paper, and display boxes. These supplies will most likely be available through Dr. Delaney's lab in the Department of Entomology and Wildlife Ecology. Use of GIS and other software is also available through resources at the University of Delaware. Reference List: Arnan, X., Bosch, J., Comas, L., Gracia, M., and Retana, J. (2011). Habitat determinates of abundance, structure and composition of flying Hymenoptera communities in mountain old-growth forests. Insect Conservation and Diversity, 4, doi: /j x Bonet, A. (2008). Parasitoid Wasps, Natural Enemies of Insects. In Tropical Biology and Conservation Management (Vol. VII). Retrieved from Cracraft, J., & Grifo, F. T. (Eds.). (1999). The Living Planet in Crisis: Biodiversity Science and Policy. Chichester, NY: Columbia University Press. Evans, A. V. (2008). Field Guide to Insects and Spiders of North America. New York, NY: Sterling Publishing Co., Inc. Hilszczanski, J., Gibb, H., Hjalten, J., Atlegrim, O., Johansson, T., Pettersson, R., Ball, J., Danell, K., (2005). Parasitoids (Hymenoptera, Ichneumonoidea) of Saproxylic beetles are affected by forest successional stage and dead wood characteristics in boreal spruce forest. Biological Conservation, 126, Lassau, S.A. & Hochuli, D.F. (2005) Wasp community responses to habitat complexity in Sydney sandstone forests. Austral Ecology, 30, Royal Entomological Society. (2014). Parasitoid Wasps (Hymenoptera). Retrieved from Welsh, J. (2012, Mar. 12). Call of the Wild: How Predators Increase Diversity. livescience. Retrieved from 5