Document: MAT-3-71-6

Patterns of abundance of a potential facilitator in container insect communities.

DAUGHERTY, M.P.*, S.L.VANRHEIN, M.E.GRAVEL and S.A.JULIANO

Illinois State University, Normal, IL 61790-4120 USA ¹

Abstract:
In container insect communities, leaf scraping scirtid beetles (family scirtidae) are thought to facilitate filter feeding mosquitoes (Aedes triseriatus) by processing course leaf litter into fine particles. Such interactions are known as processing chains because multiple consumer species sequentially utilize one resource at different resource states. Understanding factors that influence the abundance of these beetles may provide information regarding the importance of processing chains in container communities. In this study, we examined how container type (i.e., natural vs. artificial), container size, and resource amount influence the abundance of scirtids. Each month, for 11 months, we non-destructively sampled 12 tree holes and 8 tires, counting all living scirtids and A. triseriatus. We measured maximum container volume, and the initial amount of accumulated plant detritus and sediment for each container. Tree holes supported significantly greater monthly densities in late fall and significantly greater cumulative densities of scirtids than did tires. However, differences in scirtid abundance were not due to inherent differences in container size or resource amount between tree holes and tires. Results of a path analysis suggest that container size exerts strong influences on litter amount and scirtid abundance, but leaf litter amount does not directly affect scirtid abundance. Amount of leaf litter and scirtid abundance appear to be strongly correlated because they are both determined by container size.

Keywords: processing chain, scirtidae, container insect communities

This abstract is being presented at: 10:30 AM in session:
Poster Session #9: Fish, Lakes, Streams and Wetlands.