March 1 2018

5:00 pm 1100 TLSB

EcoEvoPub Series

Graduate Student Presentations


Shawn McEachin
Department of Ecology and Evolutionary Biology, UCLA

“Effects of microhabitat selection on interspecific aggression in male rubyspot damselflies (Calopterygidae: Hetaerina)”

Interspecific interference competition is common among phenotypically similar species in sympatry. Selection may favor mechanisms that reduce interspecific aggression when species do not compete for a limited resource. Reduced levels of interspecific aggression can arise through a reduction in heterospecific encounter rates via microhabitat partitioning. I explore the relationship between the levels of aggression between species of male rubyspot damselflies (Hetaerina) and microhabitat utilization. Preliminary evidence suggests a negative correlation between levels of aggression and microhabitat overlap between species. Differences in microhabitat utilization may be the result of responses to competitive interactions, differences in innate microhabitat preference, or chance differences based on where males happen to settle (e.g. conspecific attraction). I discuss experiments to determine which of these mechanisms are used by rubyspot males during microhabitat selection, and the implications of microhabitat partitioning on levels of aggression between species.

Guilherme Casas Gonalves
Department of Ecology and Evolutionary Biology, UCLA

"Apparent competition and temperature: from organismal traits to community persistence"

Enemy mediated interactions, or apparent competition have been shown to happen in many different environments and taxa, and to be a relevant factor in many systems both as a community assembly mechanism and in pest control. However, despite the prevalence of apparent competition in nature, mathematical models show that coexistence can be hard to achieve without the action of some external factor, such as spatial or temporal variation. Heterogeneity in the thermal environment in particular has been shown to affect apparent competition in ecologically relevant ways. Differences in the thermal response of resource species have been shown to be a possible mechanism for enemy release on one of the apparent competitors in natural systems. In order to assess how apparent competition is affected by temperature variation and differences in trait thermal responses, I use a trait-based mathematical model that mechanistically incorporates the known trait temperature reaction curves for ectotherms. I analyze the invasibility criteria for apparent competitors and derive a condition for mutual invasibility based on the parameters of the trait temperature response curves. I then use this condition to assess how differences between species promote or hinder the species ability to coexist.

Thursday, March 1, 2018
1100 Terasaki Life Sciences Building











































































































































































































































































































































































































































































































































































































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