Reproductive and Somatic Effort Distribution of a plant parasite on its host and Reproductive and...
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Distribution of a plant parasite on its host and Reproductive and Somatic Effort BIOL 3060
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Transcript of Reproductive and Somatic Effort Distribution of a plant parasite on its host and Reproductive and...
Distribution of a plant parasite on its host
and
Reproductive and Somatic Effort
BIOL 3060
Distribution of a plant parasite on its host: gall distribution on the flowering dogwood, Cornus florida
Flowering dogwood, Cornus florida
Midge fly, Resseliella clavula
Purpose• To determine the distribution of
midge galls on dogwood trees and to investigate some environmental factors that might influence distribution.
Questions1) How are the galls distributed spatially?
• Random vs. clumped vs. uniform
2) Could # or distribution of galls be related to:• Size/age of the plant? Nearest neighbor
distance? Sunny versus shady microhabitat?
P1: Random Distribution
• Parasites are randomly distributed within the environment. If midges flew until they “hit” a dogwood haphazardly …
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# Parasites
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P2: Even Distribution
• “Regular”: Organisms are evenly spaced in the environment. In our case, every tree would have the same number of galls. This would suggest that the parasites are competing for the trees.
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P3: Clumped Distribution
• Most trees have few parasites, and some a lot.
• Typically associated with:– disease outbreaks– tree densities (“contagious”)– age-related effects
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• Tree size• Older and infirm trees might be more
likely to be attacked by the midge parasite.
• Distance to nearest neighbor• If trees are close together, they might be
more likely to attract galls.
• Collect gall data in two habitats• Some microhabitats might be better for
galls than others.
Environmental Factors We are Measuring
Dogwood Identification (Winter)
Flower buds(reproductive)
Leaf bud(somatic)
Both
Bark: dark brown with squarish, scaly blocks.
Young trees will be smooth and not as distinctive.
Terminal Buds
Examples of different numbers of bud scales
Dogwood with two bud scales. Twigs are slender, green or purple.
Leaf Scars
Dogwood leaf scars are opposite, small, and encircle twig.
Example of alternate leaf scars
Opposite leaf scars
Terminal bud
Dogwood Identification
Flowers: white, four petals (spring)
Fruit: bright red, in clusters (late summer, fall)
Leaves: opposite, veins curved
