Browsing by Author "Dudycha, Jeffry L."

Now showing 1 - 4 of 4

Metadata only
Ancient and recent duplications support functional diversity of Daphnia opsins
(Springer, 2017-01) Brandon, Christopher S.; Greenwold, Matthew J.; Dudycha, Jeffry L.
Daphnia pulex has the largest known family of opsins, genes critical for photoreception and vision in animals. This diversity may be functionally redundant, arising from recent processes, or ancient duplications may have been preserved due to distinct functions and independent contributions to fitness. We analyzed opsins in D. pulex and its distant congener Daphnia magna. We identified [...] Copyright 2017 Gale, Cengage Learning. All rights reserved. COPYRIGHT 2017 Springer
Metadata only
Ecological constraints on sensory systems: compound eye size in Daphnia is reduced by resource limitation
(Springer, 2014-08) Brandon, Christopher S.; Dudycha, Jeffry L.
Eye size is an indicator of visual capability, and macroevolutionary patterns reveal that taxa inhabiting dim environments have larger eyes than taxa from bright environments. This suggests that the light environment is a key driver of variation in eye size. Yet other factors not directly linked with visual tasks (i.e., non-sensory factors) may influence eye size. We sought to jointly investigate the roles of sensory (light) and non-sensory factors (food) in determining eye size and ask whether non-sensory factors could constrain visual capabilities. We tested environmental influences on eye size in four species of the freshwater crustacean Daphnia, crossing bright and dim light levels with high and low resource levels. We measured absolute eye size and eye size relative to body size in early and late adulthood. In general, Daphnia reared on low resources had smaller eyes, both absolutely and relatively. In contrast to the dominant macroevolutionary pattern, phenotypic plasticity in response to light was rarely significant. These patterns of phenotypic plasticity were true for overall diameter of the eye and the diameter of individual facets. We conclude that non-sensory environmental factors can influence sensory systems, and in particular, that resource availability may be an important constraint on visual capability.
Metadata only
Population genomics of resource exploitation: insights from gene expression profiles of two Daphnia ecotypes fed alternate resources
(Blackwell Pub. Ltd, 2012-02) Dudycha, Jeffry L.; Brandon, Christopher S.; Deitz, Kevin C.
Consumer-resource interactions are a central issue in evolutionary and community ecology because they play important roles in selection and population regulation. Most consumers encounter resource variation at multiple scales, and respond through phenotypic plasticity in the short term or evolutionary divergence in the long term. The key traits for these responses may influence resource acquisition, assimilation, and/or allocation. To identify relevant candidate genes, we experimentally assayed genome-wide gene expression in pond and lake Daphnia ecotypes exposed to alternate resource environments. [...]
Open Access
Selection on incremental variation of eye size in a wild population of Daphnia
(Blackwell Science, 2015-11) Brandon, Christopher S.; James, T.; Dudycha, Jeffry L.
Several studies of eye morphology have analysed macroevolutionary patterns in the diversity of eyes, and although these studies are often linked to environment or behaviour, they provide only indirect evidence of selection. Specific data to show the microevolutionary potential for adaptation by natural selection in eye morphology have been lacking. We document directional selection on eye size, an important determinant of visual capabilities, in a wild population of the freshwater microcrustacean Daphnia. We show that [...] (© 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.)