Abstract

Life history strategies encompass a suite of co-evolved traits crucial for ensuring an individual's fitness, often evolving from trade-offs between traits competing for the same resources. Adult male crayfish in the Cambaridae family undergo seasonal morphological changes linked to reproductive status, a process called cyclic dimorphism. In this dissertation, we attempt to understand how cyclic dimorphism evolved in non-native northern crayfish (Faxonius virilis). First, in Chapter 1, we review empirical studies that have assessed animal personality across developmental periods. The results show that personality traits tend to be stable within life stages but not across developmental events. In Chapter 2, we examine growth patterns to investigate a potential trade-off between energy allocation for body size growth versus chelae size growth. We show a larger carapace length growth increment in nonreproductive crayfish and a larger growth increment in chelae length in reproductive crayfish. In Chapter 3, we investigate the interaction between behavior and various physiological traits. We find that nonreproductive crayfish had a higher metabolic rate and were in better body condition than reproductive crayfish. We also find that crayfish with higher energy stores tend to be in better body condition. Finally, in Chapter 4 we use two separate crayfish groups to test three hypotheses to understand how energy is used to finance growth. We show that nonreproductive crayfish in the wild tend to consume more food and have more energy stores than reproductive crayfish. We also show that nonreproductive captive crayfish tend to have more energy stores than reproductive crayfish. The work contained in this dissertation contributes to the understanding of the relationship between behavior and physiology and its implications on the evolution of complex life histories.

Degree

PhD

College and Department

Life Sciences; Biology

Rights

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