The influence of maternal care duration on offspring phenotypes in African cichlids

The first environment that an individual experiences is created by its parents and, for many species, the female parent has a particularly central role in caring for offspring throughout early development. Through maternal care, mothers can shape how their offspring interact with the environment and increase offspring growth and survival. Maternal care quality, as a measure of number of positive interactions, and duration, as a measure of length of time until individuals are independent, varies among individual females, possibly resulting in variation in offspring phenotypes. Investigating the effects of variation in maternal care quality or duration can provide insights into how and why offspring phenotypic variation develops. Examining maternal care effects can then increase our understanding of phenotypic variation that may affect how individuals interact with and succeed in their environment. An individual’s morphological development is at least partially influenced by its environment, and morphology can in turn shape the interaction between an individual and its environment. To begin to understand how the maternal environment influences morphological development, I investigated how natural and artificial variation in maternal mouthbrooding duration alters craniofacial shape in four African cichlid species (Chapter Two). Craniofacial shape is an important morphological trait for food acquisition, which can be highly species specific. Using geometric morphometric techniques, I found that craniofacial shape became less convex as maternal care duration decreased, but that this relationship was most pronounced in species with a generalist diet. These findings indicate that duration of maternal care may be related to food acquisition and preferences, which could lead to differential success in unpredictable environments. Behavioural traits such as boldness and aggression can be important for growth, reproduction and survival. Behavioural development can be influenced by maternal care, which also influences brain development. Brain morphology has been linked to specific behaviours, though it is not understood what role maternal care has in the development of this link. I examined the relationship between reduced maternal mouthbrooding duration and brain anatomy and the relationships among morphological variation in brain volume and behaviours (Chapters Three and Four). I also examined how a reproductively essential trait, aggression between males in a competitive environment, is related to maternal care duration (Chapter Four). Overall, I found that maternal care duration was not directly related to behaviour or brain volume in adult offspring. However, individuals reared under different maternal care durations exhibited different sets of correlated behaviours. Aggression and inactivity in reduced care individuals was positively associated with the volume of the hypothalamus, while aggression, shyness and lack of exploration in full care individuals was negatively associated with the hypothalamus (Chapter Three). Further investigation of the relationship between aggressive behaviours and the hypothalamus indicated that a greater number of bites per second was negatively associated with the volume of the hypothalamus (Chapter Four). Taken together these results suggest that maternal care duration influences the relationship between the hypothalamus and aggression. Additionally, I examined the associations among bi-parental presence during early development and aggression in sub-adult offspring (Chapter Five). Parental absence did not have a direct relationship with offspring timidity or fight escalation but did relate to offspring size and offspring size, in turn, was associated with escalation. The results of Chapters Three, Four and Five suggest that maternal care duration may be related to boldness and aggression, though it may be through different mechanisms (i.e. brain anatomy or offspring size). Furthermore, Chapters Four and Five indicated that individuals with reduced duration of parental care had greater variation in the expression of behaviours than individuals receiving full care. These differences in ranges of phenotypic variation between treatment groups, suggest that increased maternal care duration may restrict phenotypic variation and reduce plasticity within stable environments. Overall, these results suggest that variation in maternal care is related to variation in offspring development and can alter how individuals interact with their environment. Individual phenotypic variation, in terms of morphology and behaviour, is shaped by some of the earliest experiences individuals have with their environment. The morphological and behavioural variation observed could alter how individuals acquire food, protect resources such as shelter and mates, and could potentially extend to reproductive success. These findings suggest that maternal care, as the first environment offspring experience is exceedingly important to how individuals develop and interact with their environment. Furthermore, variation in maternal care duration among females may serve as pathway through which evolution may occur, due to resulting in phenotypic variation and plasticity in offspring

Reduced exploration capacity despite brain volume increase in warm-acclimated common minnow

While evidence suggests that warming may impact cognition of ectotherms, the underlying mechanisms remain poorly understood. A possible but rarely considered mechanism is that the metabolic response of ectotherms to warming is associated with changes in brain morphology and function. Here, we compared aerobic metabolism, brain volume, boldness and accuracy of maze solving of common minnows (Phoxinus phoxinus) acclimated for 8 months to either their current optimal natural (14°C) or warm (20°C) water temperature. Metabolic rates indicated increased energy expenditure in warm-acclimated fish, but also at least partial thermal compensation as warm-acclimated fish maintained high aerobic scope. Warm-acclimated fish had larger brains than cool-acclimated fish. The volume of the dorsal medulla relative to the overall brain size was larger in warm- than in cool-acclimated fish, but the proportion of other brain regions did not differ between the temperature treatments. Warm-acclimated fish did not differ in boldness but made more errors than cool-acclimated fish in exploring the maze across four trials. Inter-individual differences in the number of exploration errors were repeatable across the four trials of the maze test. Our findings suggest that in warm environments, maintaining a high aerobic scope, which is important for the performance of physically demanding tasks, can come at the cost of changes in brain morphology and impairment of the capacity to explore novel environments. This trade-off could have strong fitness implications for wild ectotherms

Oil exposure alters social group cohesion in fish

Many animal taxa live in groups to increase foraging and reproductive success and aid in predator avoidance. For fish, a large proportion of species spend all or part of their lives in groups, with group coordination playing an important role in the emergent benefits of group-living. Group cohesion can be altered by an array of factors, including exposure to toxic environmental contaminants. Oil spills are one of the most serious forms of pollution in aquatic systems, and while a range of effects of acute oil exposure on animal physiology have been demonstrated, sub-lethal effects on animal behavior are relatively under-studied. Here we used an open-field behavioral assay to explore influence of acute oil exposure on social behavior in a gregarious fish native to the Gulf of Mexico, Atlantic croaker (Micropogonias undulatus). We used two oil concentrations (0.7% and 2% oil dilution, or 6.0 ± 0.9 and 32.9 ± 5.9 μg l−1 ΣPAH50 respectively) and assays were performed when all members of a group were exposed, when only one member was exposed, and when no individuals were exposed. Shoal cohesion, as assessed via mean neighbor distance, showed significant impairment following acute exposure to 2% oil. Fish in oil-exposed groups also showed reduced voluntary movement speed. Importantly, overall group cohesion was disrupted when even one fish within a shoal was exposed to 2% oil, and the behavior of unexposed in mixed groups, in terms of movement speed and proximity to the arena wall, was affected by the presence of these exposed fish. These results demonstrate that oil exposure can have adverse effects on fish behavior that may lead to reduced ecological success

Defining and modeling known adverse outcome pathways: Domoic acid and neuronal signaling as a case study

An adverse outcome pathway (AOP) is a sequence of key events from a molecular-level initiating event and an ensuing cascade of steps to an adverse outcome with population-level significance. To implement a predictive strategy for ecotoxicology, the multiscale nature of an AOP requires computational models to link salient processes (e.g., in chemical uptake, toxicokinetics, toxicodynamics, and population dynamics). A case study with domoic acid was used to demonstrate strategies and enable generic recommendations for developing computational models in an effort to move toward a toxicity testing paradigm focused on toxicity pathway perturbations applicable to ecological risk assessment. Domoic acid, an algal toxin with adverse effects on both wildlife and humans, is a potent agonist for kainate receptors (ionotropic glutamate receptors whose activation leads to the influx of Na + and Ca 2+ ). Increased Ca 2+ concentrations result in neuronal excitotoxicity and cell death, primarily in the hippocampus, which produces seizures, impairs learning and memory, and alters behavior in some species. Altered neuronal Ca 2+ is a key process in domoic acid toxicity, which can be evaluated in vitro. Furthermore, results of these assays would be amenable to mechanistic modeling for identifying domoic acid concentrations and Ca 2+ perturbations that are normal, adaptive, or clearly toxic. In vitro assays with outputs amenable to measurement in exposed populations can link in vitro to in vivo conditions, and toxicokinetic information will aid in linking in vitro results to the individual organism. Development of an AOP required an iterative process with three important outcomes: a critically reviewed, stressor-specific AOP; identification of key processes suitable for evaluation with in vitro assays; and strategies for model development. Environ. Toxicol. Chem. 2011;30:9–21. © 2010 SETACPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78481/1/373_ftp.pd

Development and Validation of a Symptom-Based Activity Index for Adults With Eosinophilic Esophagitis

Standardized instruments are needed to assess the activity of eosinophilic esophagitis (EoE), to provide endpoints for clinical trials and observational studies. We aimed to develop and validate a patient-reported outcome (PRO) instrument and score, based on items that could account for variations in patients’ assessments of disease severity. We also evaluated relationships between patients’ assessment of disease severity and EoE-associated endoscopic, histologic, and laboratory findings

Sorghum jalapense

https://thekeep.eiu.edu/herbarium_specimens_byname/18743/thumbnail.jp

Gomphrena decumbens Moq.

https://thekeep.eiu.edu/herbarium_specimens_byname/8023/thumbnail.jp

Cyperus planifolius Rich.

https://thekeep.eiu.edu/herbarium_specimens_byname/8024/thumbnail.jp

Sporobolus muralis (Raddi) Hitchc. & Chase

https://thekeep.eiu.edu/herbarium_specimens_byname/8025/thumbnail.jp