Does Competition for Food Result in Lady Beetle Decline?

Graduate student Denisha Parker is going to determine if native lady beetles that have remained common following the introduction of exotic species have a low degree of dietary niche overlap with their competitors. If this is true, it would aid in our understanding of why some species have declined dramatically following exotic introductions while others have remained. Denisha was recently awarded a highly competitive North Central Region Sustainable Agriculture Research and Education Graduate Student Grant ($11,924) to support her work. She will be collecting two species of lady beetles (checker-spot lady beetle (exotic) and orange spotted lady beetle (native)) from our control and high-diversity wildflower vacant lot plots as well as urban farms using sweep nets and sticky traps. Using molecular gut content analysis she will determine the diet of these species and determine how much overlap exists and if it varies by foraging habitat.

Project Description: Native lady beetles are an important group of urban agricultural predators, but in recent decades many have declined dramatically coinciding with introductions of exotic lady beetle competitors. We will determine if the degree of overlap in predator diet, a form of exploitative competition, explains why some native species have declined while others have remained common following exotic establishment.  Using this information, we can manage greenspaces to both conserve native biodiversity and promote urban farm sustainability.



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