Insects that rely upon ephemeral resources for feeding and reproduction often respond to a specific compound or suite of compounds in order to effectively exploit a resource. Due to the short-lived and patchy nature of resources like dung, carrion, and decomposing fungi, competitive pressures can be great; therefore, temporal and spatial partitioning are paramount if these ecologically similar species are to coexist. Two species of saprophytic Scarabaeidae were investigated: Ateuchus histeroides, known to prefer dung, and Geotrupes splendidus, an opportunistic species. Wind-tunnel bioassays were performed with dung, carrion, and fungus at 24-hour intervals of decomposition to determine attractiveness in time. Response to dung greatly decreased after 24 hours; however, response to carrion and fungi increased as the substrate aged. Gas chromatography-Mass Spectrometry was used to separate and identify volatile compounds at 24-hour intervals, and synthetic blends of common compounds were tested with selected species using wind-tunnel bioassays. Alcohols, such as 3- & 4-Methyl phenol, sulfides, such as Dimethyl disulfide and Dimethyl trisulfide, and aldehydes, such as Nonanal were found to be potential key compounds in attracting the species of interest. Results suggest that, although these species exhibit feeding preferences, they will respond to a variety of resources.
Species 1: Coleoptera Scrarabaeidae Ateuchus histeroides
Species 2: Coleoptera Scarabaeidae Geotrupes splendidus
Keywords: gas chromatography-mass spectrometry, resource partitioning
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