2011 Student Research Conference:
24th Annual Student Research Conference

What Gall! How Consistent is Prey and Natural Selection by Downy Woodpeckers on Goldenrod Galls Through the Winter?
John H. Kimbrough
Dr. Peter Goldman, Faculty Mentor

We examined the trophic relationship between Downy Woodpeckers (Picoides pubescens), ball gall flies (Eurosta soladiginis), goldenrods (Solidago altissima), and the parasitoid wasp Eurytoma gigantea. During winter, woodpeckers prey upon the larvae of the ball gall fly which are encased in galls in the stems of goldenrods, preferring larger galls. Wasps lay their eggs on developing fly larvae and eventually devour the host and emerge from the gall. We characterized the gall size selection by Downy Woodpeckers in two old field habitats in northeast Missouri and found that woodpeckers preferentially select the largest available galls throughout winter, even though the average size of available galls decreases as the season progresses. We experimentally added holes to galls to mimic the exit hole of wasps to determine if woodpeckers respond to visual cues when selecting galls to excavate. There was no significant difference in the frequency of excavation between experimental and control galls.

Keywords: Downy woodpecker, ecology , natural selection , trophic interactions, parasitoid, galls , old field habitats, goldenrods


Presentation Type: Poster

Session: 3-2
Location: Georgian Room - SUB
Time: 4:30

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