Conservation physiology (CP) and nutritional ecology (NE) are both integrative sciences that share the fundamental aim of understanding the patterns, mechanisms and consequences of animal responses to changing environments. Here, we explore the high-level similarities and differences between CP and NE, identifying as central themes to both fields the multiple timescales over which animals adapt (and fail to adapt) to their environments, and the need for integrative models to study these processes. At one extreme are the short-term regulatory responses that modulate the state of animals in relation to the environment, which are variously considered under the concepts of homeostasis, homeorhesis, enantiostasis, heterostasis and allostasis. In the longer term are developmental responses, including phenotypic plasticity and transgenerational effects mediated by non-genomic influences such as parental physiology, epigenetic effects and cultural learning. Over a longer timescale still are the cumulative genetic changes that take place in Darwinian evolution. We present examples showing how the adaptive responses of animals across these timescales have been represented in an integrative framework from NE, the geometric framework (GF) for nutrition, and close with an illustration of how GF can be applied to the central issue in CP, animal conservation.
Farewell Spit gannetry in New Zealand. Our results showed intra-and inter-specific variation in the protein, lipid and water composition of prey captured by our sample of 111 Australasian gannets. In addition, we observed significant differences in the Australasian gannets' nutritional niche between seasons. We provide evidence of sex-specific macronutrient foraging strategies in a successful marine predator in the wild. We have shown that in spite of fluctuations in the nutritional composition of foods available to Australasian gannets, males consistently capture prey with higher protein-to-lipid ratios and lower lipid-to-water ratios than females. These results aid to better understand the evolutionary relationship between macronutrient selection and sex-specific traits in wild animals. They also suggest an incentive for these predators to combine individually imbalanced but nutritionally complementary foods to achieve dietary balance, further highlighting the likelihood that prey selection is guided by the balance of macronutrients, rather than energy alone.
Research has shown that if a mother experiences a transitory perturbation to her environment during pregnancy or lactation, there are transgenerational consequences often involving a disordered metabolic phenotype in first generation offspring with recovery across subsequent generations. In contrast, little is known about the nature of the transgenerational response of offspring when a mother experiences a perturbation that is not transitory but instead persists across generations. Our study, using a rat model, subjected the parental generation to a change in environment and concomitant shift from a grain-based to obesogenic diets to generate an adipose phenotype in first generation offspring emulating a common scenario in human urbanisation and migration. We then investigated whether the obese phenotype was stable across generations when maintained in the transitioned environment, and whether dietary macronutrient balance affected the response. We found that second and third generation offspring had a reduced body fat to lean mass ratio and a reduced appetite relative to first generation offspring, irrespective of dietary macronutrient balance. The trajectory of this response is suggestive of a reduction in chronic disease risk across generations. This is one of the first studies, to our knowledge, to investigate the transgenerational response following parental transition to a persistent obesogenic environment, and to demonstrate that successive generations respond differently to this constant environment.
Unfortunately, the second research question was incorrectly published in the "Introduction" and "Results" sections of the original article. The correct question is given below. Do female and male Australasian gannets target different prey combinations? The online version of the original article can be found under
Abstract:Little is known about how diurnal raptors, as apex predators, select their prey. It has been hypothesised that they are opportunistic, taking prey according to availability, and that they select prey based on prey size. The threatened New Zealand falcon or kārearea (Falco novaeseelandiae) is New Zealand's only remaining endemic bird of prey. A previous study on prey caught by kārearea during the breeding season suggested that introduced avian prey were taken more often than expected, and endemic avian prey taken less often than expected, based on their abundance. There is a growing interest in the role that nutrients play in prey selection by predators. We used the nutritional geometry framework in a field study to determine the role that nutritional composition plays in prey choice. We built on an existing dataset to assess whether prey selection by kārearea can be explained based on prey body-mass, abundance, or nutritional characteristics. We determined the protein-to-lipid ratio and ash content of individuals across 16 species of prey and potential prey, including both endemic and introduced species, and modelled these against known prey consumption based on our earlier work. We found limited evidence for selective predation based on nutrient balancing. Instead, the relative abundance of each species in the surrounding habitat and the endemicity of each species were the most important predictors, with species body-mass playing only a minor role in prey choice. To investigate the apparent selection for introduced over endemic prey, future research could compare the behavioural adaptations of endemic birds against their natural predator with behaviours of introduced birds.
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