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Divergence In Thyroid Hormone Concentrations Between Juveniles Of Marine And Stream Ecotypes Of The Threespine Stickleback (Gasterosteus Aculeatus), Jun Kitano, Sean C. Lema
Divergence In Thyroid Hormone Concentrations Between Juveniles Of Marine And Stream Ecotypes Of The Threespine Stickleback (Gasterosteus Aculeatus), Jun Kitano, Sean C. Lema
Sean Lema
Background: Hormones regulate the expression of multiple phenotypic traits. Therefore,
divergence in hormone concentrations may lead to evolutionary changes in the coordinated
physiological and behavioural traits that comprise an organism’s integrated phenotype. Adults
of marine ecotypes of threespine stickleback (Gasterosteus aculeatus) have higher concentrations
of the thyroid hormone thyroxine (T4) than adults of stream-resident ecotypes (Kitano
et al., 2010). Thyroid hormones are well-established mediators of osmoregulation and migratory
behaviours in fish, and the difference in T4 concentrations indicates that changes in thyroid
hormone signalling may underlie the evolutionary and ecological divergence of migratory and
non-migratory ecotypes.
Questions: Is the variation …
Modeling Simultaneous Selection For Resistance And Tolerance In Goldenrod (Solidago Altissima) Across A Range Of Spittlebug Population Densities, Michael J. Wise, Warren G. Abrahamson Ii
Modeling Simultaneous Selection For Resistance And Tolerance In Goldenrod (Solidago Altissima) Across A Range Of Spittlebug Population Densities, Michael J. Wise, Warren G. Abrahamson Ii
Warren G. Abrahamson, II
Plant defenses against herbivory include two main strategies: resistance (to minimize the amount of damage) and tolerance (to minimize the fitness impact of that damage). Recent studies have emphasized the need to consider both strategies simultaneously for a fuller understanding of the evolutionary and ecological dynamics of plant defense against herbivores. We used a combination of a garden study, a greenhouse experiment, and mathematical modeling to investigate resistance to and tolerance of spittlebug damage in the goldenrod Solidago altissima. In contrast to traditional expectations, the genetic correlation between resistance and tolerance was highly positive. Selection gradients indicated that directional selection …
The Effect Of Resource Stress On Goldenrod's Tolerance Of Folivory Depends More On The Identity Of The Stress Than On The Severity Of The Stress, Peter J. March, Michael J. Wise, Warren G. Abrahamson Ii
The Effect Of Resource Stress On Goldenrod's Tolerance Of Folivory Depends More On The Identity Of The Stress Than On The Severity Of The Stress, Peter J. March, Michael J. Wise, Warren G. Abrahamson Ii
Warren G. Abrahamson, II
It is widely accepted that the levels of resources in a plant’s environment can influence the plant’s ability to compensate for (i.e., tolerate) damage by herbivores. However, predicting the direction of the influence has proven difficult. Here, we report on a greenhouse study in which individuals of Solidago altissima were exposed to factorial combinations of light and fertilization levels to investigate how different types of stresses affect plants’ ability to tolerate leaf damage by larvae of the beetle Trirhabda virgata. Shade stress reduced the plants’ tolerance of herbivory, while nutrient stress had no effect on tolerance. These results did not …