Cris Hochwender
Dr. Cris Hochwender earned his bachelor’s in biology at Cornell College and completed his PhD in biology at the University of Missouri-St. Louis. He has carried out research in the area of evolutionary ecology for 25+ years. His research has explored plant defense against herbivores, plant tolerance to damage, local adaptation of plants, and structuring forces of arthropod herbivore communities. More recently, he has addressed questions that center on restoration ecology. Those questions have involved a tropical forest restoration project in Costa Rica, a local prairie wetland restoration project in Indiana, and management practices of an ancient forest in Indiana.
Dr. Hochwender has taught courses in the Department of Biology and for the Environmental Studies program at the University of Evansville since 2001. While those courses have spanned a broad range of topics, many of his courses have provided perspectives on biostatistics, ecology, evolution, and environmental science.
Other than engaging students in conversations about their academic lives, Dr. H enjoys turning ceramics on the wheel (bowls are the best!), playing racketball, hiking, promoting native plants in flower gardens, and fluffy kittens.
Supervisors: Dr. Robert Marquis at UMSL (graduate advisor) , Dr. Robert Fritz at Vassar (post-doc advisor). , and Clearly, only people named Bob are allowed to supervise me.
Dr. Hochwender has taught courses in the Department of Biology and for the Environmental Studies program at the University of Evansville since 2001. While those courses have spanned a broad range of topics, many of his courses have provided perspectives on biostatistics, ecology, evolution, and environmental science.
Other than engaging students in conversations about their academic lives, Dr. H enjoys turning ceramics on the wheel (bowls are the best!), playing racketball, hiking, promoting native plants in flower gardens, and fluffy kittens.
Supervisors: Dr. Robert Marquis at UMSL (graduate advisor) , Dr. Robert Fritz at Vassar (post-doc advisor). , and Clearly, only people named Bob are allowed to supervise me.
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Papers by Cris Hochwender
• Premise of the study: In dioecious species, selection should favor different leaf sizes in males and females whenever the sexes experience distinct environments or constraints such as different costs of reproduction. We took advantage of a long-term experimental study of Ocotea tenera (Lauraceae), a dioecious understory tree in Monteverde, Costa Rica, to explore leaf size differences between genders and age classes across generations.
• Methods: We measured leaf size in adult trees in a natural population, in their adult F1 offspring in two experimental popula- tions, and in their F2 offspring at the seedling stage. Individual trees were measured at various times over 20 yr.
• Results: Leaves of female trees averaged 8% longer and 12% greater in area than those of males. Leaves were sexually dimor- phic at reproductive maturity. Leaf size declined during the lifetime of most trees. Heritability estimates for leaf length were positive although not statistically significant (h2 = 0.63, SE = 0.48, P = 0.095).
• Conclusions: We ruled out the ecological causation hypothesis for sexual dimorphism in leaf size because male and female trees co-occurred in the same habitats. Sexual dimorphism appeared not to result from genetic or phenotypic correlations with other traits such as height or flower size. Rather, females appear to compensate for higher costs of reproduction and diminished photosynthetic capacity by producing larger leaves. Additive genetic variance in leaf size, a prerequisite for an evolutionary response to selection for sexual dimorphism, was suggested by positive (although only marginally significant) heritability estimates.
• Premise of the study: In dioecious species, selection should favor different leaf sizes in males and females whenever the sexes experience distinct environments or constraints such as different costs of reproduction. We took advantage of a long-term experimental study of Ocotea tenera (Lauraceae), a dioecious understory tree in Monteverde, Costa Rica, to explore leaf size differences between genders and age classes across generations.
• Methods: We measured leaf size in adult trees in a natural population, in their adult F1 offspring in two experimental popula- tions, and in their F2 offspring at the seedling stage. Individual trees were measured at various times over 20 yr.
• Results: Leaves of female trees averaged 8% longer and 12% greater in area than those of males. Leaves were sexually dimor- phic at reproductive maturity. Leaf size declined during the lifetime of most trees. Heritability estimates for leaf length were positive although not statistically significant (h2 = 0.63, SE = 0.48, P = 0.095).
• Conclusions: We ruled out the ecological causation hypothesis for sexual dimorphism in leaf size because male and female trees co-occurred in the same habitats. Sexual dimorphism appeared not to result from genetic or phenotypic correlations with other traits such as height or flower size. Rather, females appear to compensate for higher costs of reproduction and diminished photosynthetic capacity by producing larger leaves. Additive genetic variance in leaf size, a prerequisite for an evolutionary response to selection for sexual dimorphism, was suggested by positive (although only marginally significant) heritability estimates.