Investigating Mate Choice in the Dogbane Leaf Beetle, Chrysochus auratus
Location
Turner Gymnasium
Access Type
Open Access
Entry Number
51
Start Date
4-5-2023 12:00 PM
End Date
4-5-2023 1:30 PM
College
Lynchburg College of Arts and Sciences
Department
Biology
Abstract
The dogbane leaf beetle, Chrysochus auratus, is one of the most recognizable beetle species in eastern North America because it is large, brilliantly metallic blue and green, and feeds only on dogbane (Apocynum cannabinum), a plant that produces cardenolides highly toxic to most other plant-feeding insects. Despite being so charismatic, very little is known about the natural history of dogbane leaf beetles. Previous research on these beetles has focused almost exclusively on hybridization with a sister species, the blue milkweed beetle in the western United States. Male and female dogbane leaf beetles are not sexually dimorphic, but they are highly promiscuous and there is some speculation in the literature that males are choosy about the females they mate with. No data, however, have been published to support this, so I investigated their mating behavior for evidence and mechanisms of mate choice. I collected mated pairs of beetles, as well as single male and single female beetles to determine if beetles that were successful at mating differed morphologically from beetles that were not found mating. I compared several measures of body size between mated and unmated beetles within each sex and also tested for positive assortative mating. Results show that while there was no difference in size between mated and unmated males, mated females were significantly larger than unmated females, suggesting that males prefer larger females. There was no evidence of positive assortative mating. Larger females may be attractive to males because they produce more or larger eggs, but such a preference may lead to greater sperm competition among males.
Faculty Mentor(s)
Dr. John Styrsky Dr. Kari Benson
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Investigating Mate Choice in the Dogbane Leaf Beetle, Chrysochus auratus
Turner Gymnasium
The dogbane leaf beetle, Chrysochus auratus, is one of the most recognizable beetle species in eastern North America because it is large, brilliantly metallic blue and green, and feeds only on dogbane (Apocynum cannabinum), a plant that produces cardenolides highly toxic to most other plant-feeding insects. Despite being so charismatic, very little is known about the natural history of dogbane leaf beetles. Previous research on these beetles has focused almost exclusively on hybridization with a sister species, the blue milkweed beetle in the western United States. Male and female dogbane leaf beetles are not sexually dimorphic, but they are highly promiscuous and there is some speculation in the literature that males are choosy about the females they mate with. No data, however, have been published to support this, so I investigated their mating behavior for evidence and mechanisms of mate choice. I collected mated pairs of beetles, as well as single male and single female beetles to determine if beetles that were successful at mating differed morphologically from beetles that were not found mating. I compared several measures of body size between mated and unmated beetles within each sex and also tested for positive assortative mating. Results show that while there was no difference in size between mated and unmated males, mated females were significantly larger than unmated females, suggesting that males prefer larger females. There was no evidence of positive assortative mating. Larger females may be attractive to males because they produce more or larger eggs, but such a preference may lead to greater sperm competition among males.