Sibling egg cannibalism by neonates of the Colorado potato beetle, Leptinotarsa decemlineata
Item
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Title
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Sibling egg cannibalism by neonates of the Colorado potato beetle, Leptinotarsa decemlineata
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Identifier
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d_2009_2013:bbd99075d9fc:11773
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identifier
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12425
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Creator
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Collie, Karyn Renae,
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Contributor
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Mitchell B. Baker
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Date
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2013
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Language
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English
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Publisher
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City University of New York.
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Subject
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Behavioral sciences | Entomology | Ecology | competition | costs of pesticide resistance | geographic variation | inclusive fitness | kin recognition | kin selection
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Abstract
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Cannibalism reduces competition and provides nutritional benefits. However, when cannibalism involves kin, the benefits obtained must balance inclusive fitness losses, and cannibals should be under selection to avoid killing close relatives. Since cannibalism reduces competition, it may also be higher in populations with greater population density. Neonates of the Colorado potato beetle (CPB), Leptinotarsa decemlineata, readily consume eggs within their natal clutch, which is a combination of full and half siblings, before assessing resource availability, suggesting an evolutionary response to potential resource limitation that should vary with competition between populations. CPB is also a crop pest that rapidly develops resistance to pesticides, but pesticide resistance can result in fitness costs in the absence of pesticide exposure; these costs may be mediated by cannibalism. To explore the fitness consequences of cannibalism, I fed neonates with only potato foliage or with eggs and potato foliage and measured growth and development rates. I used individuals from pesticide-susceptible and pesticide-resistant populations to test for costs of resistance and whether there is an interaction between the benefits of cannibalism and resistance. To determine whether neonates avoid killing relatives, I tested whether hatchlings recognize kin, whether they prefer inviable to viable eggs, and whether egg development is a cue for viability. To explore geographic variation in cannibalism, I studied three CPB populations and a population of L. undecimlineata on their native host plants in Mexico to assess differences in competition and cannibalism propensity. Cannibals gained mass and developed more quickly than noncannibals. When mortality risk is high, this decreased development time can reduce the mortality risk sufficiently to balance the inclusive fitness loss of eating a half sibling. There were costs of pesticide resistance, but the benefits of cannibalism reduced many of these costs. Neonates preferred eating eggs from another population, but they did not distinguish among eggs from their own population based on relatedness. They did, however, preferentially consume inviable eggs but did not use egg development as a cue for viability. Cannibalism rates were usually higher in the populations with the highest egg densities, although interspecific comparisons did not show the same pattern.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Biology
