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Phenotypic Plasticity and Maternal Effects. Short-term responses to changing climates?. Changing Thermal Environments. Current Climate Models Predict an Increasingly Warmer World. Organismal response to rising temperatures. Ecological Response. Shifts in Distribution. Δ Phenology.
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Phenotypic Plasticity and Maternal Effects Short-term responses to changing climates?
Changing Thermal Environments Current Climate Models Predict an Increasingly Warmer World
Ecological Response Shifts in Distribution Δ Phenology
Failure to Adapt Extinction Creative Commons/Bart Heird
Another response (short term) Plasticity & Maternal Effects
Adaptive Plasticity in Novel Environments Reaction Norms – low cost to fitness persistence of plasticity φ Normal Range of Developmental Temperatures Novel Low Novel High “Release” of cryptic variation in novel environments. Selection on G x E.. after Ghalambor et al. 2007. Functional Ecology 21:397
BAH, CIB, etc. • Most tests of these hypotheses involve Developmental Plasticity • i.e., irreversible phenotypic changes induced by rearing conditions
Plasticity in Reproduction • How do gravid (pregnant) females respond to warming?
Manipulation of thermal regime experienced by gravid females
Developmental stage is sensitive to thermal conditions experienced by gravid females
Why Females? Females can manipulate the phenotype of her offspring depending on intrinsic and extrinsic conditions Hormones (Cort, Androgens), Tb of dam
How can females affect offspring phenotype? • Hormones • Offspring Provisioning • Incubation Temperatures during embryonic development • Viviparous Lizards • Maternal Tb • Oviparous Lizards • Nest Site Selection
How does elevated CORT effects and costs of immune response mediate offspring quality Altered niche attributes initiate stress response Population dynamics Consequences Extended Warm Spells Rising Temperatures Altered Population Dynamics Maternal Condition Repro- Success/ Offspring Traits Decreasing rainfall Adaptive maternal effects (mainly organizational effect of hormones and immunity products) modify individual strategy and survival later on. One outcome is the induction of offspring phenotypes to cope with novel environments.
Maternal Effects & Developmental Plasticity Stressor Could be Ta CORT Energy Stores ¥ Maternal Survival Clutch Size/Offspring Size Trade-off Dispersal Philopatry Growth Rate Offspring “Quality”
CORT treated lizards remained in shelters longer than controls
Plasticity in Dorsal Pattern Zootoca (=Lacerta) vivipara
Mechanism of Induction Juvenile dorsal pattern affected by: May Ta during Gestation August Ta year before pregnancy x
Significance of Dorsal Pattern Behavior and performance covary with dorsal pattern Brodie 1992 Evolution
Temporal variation in % reticulated morphs Frequency of Reticulate females decreased with elevation only in 2008 “Cool”Year Evidence for plasticity in morphs
Maximum velocity increased with habitat openness F3,349 = 3.05, p < 0.02 Speed differed between years F3,349 = 7.82, p < 0.001 Speed differed between morphs F3,349 = 3.35, p < 0.01
Number of stops increases with habitat openness Reticulate females stopped more frequently than linear females Chi-square = 5.42, P < 0.01
Conclusions • Climate can induce variation in reproductive performance • Variation in conditions experienced by females can affect offspring phenotype • Whether female manipulation benefits offspring depends on conditions at hatching (birth)