A meta-analysis of latitudinal variations in life-history traits of roach, Rutilus rutilus, over its geographical range: linear or non-linear relationships?

1. We collated information from the literature on life history traits of the roach (a generalist freshwater fish), and analysed variation in absolute fecundity, von Bertalanffy parameters, and reproductive lifespan in relation to latitude, using both linear and non-linear regression models. We hypothesized that because most life history traits are dependent on growth rate, and growth rate is non-linearly related with temperature, it was likely that when analysed over the whole distribution range of roach, variation in key life history traits would show non-linear patterns with latitude.

Macronutrient balance mediates trade-offs between immune function and life history traits

1. Diet and health are intimately linked and recent studies have found that caloric restriction can affect immune function. However, when given a choice between diets that differ in their macronutrient composition, pathogen-infected individuals can select a diet that improves their survival, suggesting that the nutritional composition of the diet, as well as its calorie content, can play a role in defence against disease. Moreover, as individuals change their diet when infected, it suggests that a diet that is optimal for growth is not optimal for immunity, leading to trade-offs.
2. Currently, our knowledge of the effects of diet on immunity is limited because previous experiments have manipulated either single nutrients or the calorie content of the diet without considering their interactive effects. By simultaneously manipulating both the diet composition (quality) and its caloric density (quantity), in both naive and immune-challenged insects, we asked how do diet quality and quantity influence an individual's ability to mount an immune response? And to what extent are allocation trade-offs driven by quantity- versus quality-based constraints?
3. We restricted individuals to 20 diets varying in their protein and carbohydrate content and used 3D response surfaces to visualize dietary effects on larval growth and immune traits. Our results show that both constitutive and induced immune responses are not limited by the total quantity of nutrients consumed, but rather different traits respond differently to variation in the ratios of macronutrients (diet quality), and peak in different regions of macronutrient space. The preferred dietary composition therefore represents a compromise between the nutritional requirements of growth and immune responses. We also show that a non-pathogenic immune challenge does not affect diet choice, rather immune-challenged insects modify their allocation of nutrients to improve their immune response.
4. Our results indicate that immune traits are affected by the macronutrient content of the diet and that no diet can simultaneously optimize all components of the immune system. To date the emphasis has been on the effects of micronutrients in improving immunity, our findings indicate that this must be widened to include the neglected impact of macronutrients on defence against disease.

Osmoregulatory traits of broad-toothed field mouse (Apodemus mystacinus) populations from different habitats

One mechanism for physiological adjustment of small mammals to different habitats and different seasons is by seasonal acclimatization of their osmoregulatory system. We examined the abilities of broad-toothed field mice (Apodemus mystacinus) from different ecosystems ('sub-alpine' and 'Mediterranean') to cope with salinity stress under short day (SD) and long day (W) photoperiod regimes. We compared urine volume, osmolarity, urea and electrolyte (sodium, potassium and chloride) concentrations. Significant differences were noted in the abilities of mice from the two ecosystems to deal with salinity load; in particular sub-alpine mice produced less concentrated urine than Mediterranean mice with SD- sub-alpine mice seeming to produce particularly dilute urine. Urea concentration generally decreased with increasing salinity, whereas sodium and potassium levels increased, however SD- sub-alpine mice behaved differently and appeared not to be able to excrete electrolytes as effectively as the other groups of mice. Differences observed provide an insight into the kinds of variability that are present within populations inhabiting different ecosystems, thus how populations may be able to respond to potential changes in their environment. Physiological data pertaining to adaptation to increased xeric conditions, as modelled by A. mystacinus, provides valuable information as to how other species may cope with potential climatic challenges.

How trophic interaction strength depends on traits

A key problem in community ecology is to understand how individual-level traits give rise to population-level trophic interactions. Here, we propose a synthetic framework based on ecological considerations to address this question systematically. We derive a general functional form for the dependence of trophic interaction coefficients on trophically relevant quantitative traits of consumers and resources. The derived expression encompasses-and thus allows a unified comparison of-several functional forms previously proposed in the literature. Furthermore, we show how a community's, potentially low-dimensional, effective trophic niche space is related to its higher-dimensional phenotypic trait space. In this manner, we give ecological meaning to the notion of the "dimensionality of trophic niche space." Our framework implies a method for directly measuring this dimensionality. We suggest a procedure for estimating the relevant parameters from empirical data and for verifying that such data matches the assumptions underlying our derivation. © Springer Science+Business Media B.V. 2009.


--------------------------------------------------------------------------------

Reaxys Database Information|

--------------------------------------------------------------------------------

Effect of target slaughter weight on production efficiency, carcass traits and behaviour of restrictively-fed gilts and intact male finisher pigs

The effect of 3 slaughter weights (85.95 or 105 kg) on performance and carcass traits of 481 pigs in single-gender groups of 13 (18 groups of gilts and 19 groups of intact males) was evaluated. Pigs (39.5 +/- 3.3 kg) were fed a liquid diet 3 times daily in a long trough. The behaviour of pigs slaughtered at 105 kg was recorded at 50, 60 and 70 days after the start of the experiment (5 groups of gilts and 4 groups of intact males). Behaviour (active, inactive, feeding) and posture (standing, lying, dog-sitting) of all pigs was recorded at 5-min intervals for 30 min prior to and 1 h after each feeding event. Slaughtering pigs at 95 kg and 105 kg delayed production by 7 and 16 days, respectively, compared to slaughtering at 85 kg (P0.05). Muscle depth increased with increasing slaughter weight (P

The effect of priming on perceptions of dog breed traits

This study examined whether priming cues embedded in mediastyle presentations shaped people's perceptions of specific dog breeds, and in particular, the German shepherd dog (GSD). Two hundred and four adult females were exposed to one of two types of media-style presentation (stories or pictures). Half of the participants in each condition were exposed to versions designed to portray the GSD in a positive light; the remainder to stimuli developed to present the same breed in a negative light. Participants subsequently rated six individual breeds of dog, including the target breed, on a number of traits (e.g., “friendliness,“ “aggression“). Analysis revealed a significant effect of priming on people's perceptions of the GSD. Participants exposed to the negative stimuli perceived this breed as significantly less approachable, and more dangerous and aggressive, than those exposed to the positive stimuli. Priming did not influence the participants' perceptions of other breeds, even those often regarded in a negative light, although there was some evidence of breed-related category-based stereotyping. Overall, results suggest that people's perceptions of dog breeds can be influenced by verbal and visual representations. The results have implications for how dogs are portrayed in the media and other publically available sources of information.

Stereotypes of Age Differences in Personality Traits: Universal and Accurate?

Age trajectories for personality traits are known to be similar across cultures. To address whether stereotypes of age groups reflect these age-related changes in personality, we asked participants in 26 countries (N = 3,323) to rate typical adolescents, adults, and old persons in their own country. Raters across nations tended to share similar beliefs about different age groups; adolescents were seen as impulsive, rebellious, undisciplined, preferring excitement and novelty, whereas old people were consistently considered lower on impulsivity, activity, antagonism, and Openness. These consensual age group stereotypes correlated strongly with published age differences on the five major dimensions of personality and most of 30 specific traits, using as criteria of accuracy both self-reports and observer ratings, different survey methodologies, and data from up to 50 nations. However, personal stereotypes were considerably less accurate, and consensual stereotypes tended to exaggerate differences across age groups.

Are phenotypic traits useful for differentiating among a priori Coregonus taxa?

A key for three putative species apparently found in three geographic areas, i.e. Coregonus clupeoides (in Scotland), Coregonus stigmaticus (in England), and Coregonus pennantii (in Wales) given in a recent review was tested quantitatively using 544 individuals from nine populations. The classification success of the key was very low (27%). It was concluded that there is currently no robust evidence for the recognition of the three putative species. Furthermore, the use of phenotypic characters alone to distinguish putative species in postglacial fish species such as those of the genus Coregonus that show homoplasy in many of these traits is questioned. In the absence of further evidence, it was concluded that a single highly variable species best describes the pattern of phenotypic variation in these U.K. populations. On this basis it is argued that taxonomic subdivision of U.K. European coregonids is inappropriate and that Coregonus lavaretus should prevail as the species name applicable to all populations.

Are systemizing and autistic traits related to talent and interest in mathematics and engineering? Testing some of the central claims of the empathizing-systemizing theory.

In two experiments, we tested some of the central claims of the empathizing-systemizing (E-S) theory. Experiment 1 showed that the systemizing quotient (SQ) was unrelated to performance on a mathematics test, although it was correlated with statistics-related attitudes, self-efficacy, and anxiety. In Experiment 2, systemizing skills, and gender differences in these skills, were more strongly related to spatial thinking styles than to SQ. In fact, when we partialled the effect of spatial thinking styles, SQ was no longer related to systemizing skills. Additionally, there was no relationship between the Autism Spectrum Quotient (AQ) and the SQ, or skills and interest in mathematics and mechanical reasoning. We discuss the implications of our findings for the E-S theory, and for understanding the autistic cognitive profile.

Cooperative traits of technology adoption: Website adoption in Irish credit unions

The purpose of this paper is to examine website adoption and its resultant effects on credit union performance in Ireland. Credit union specific factors influence adoption as does the socio-economic profile of the population from where the credit union draws its membership. Website adoption results in a reduction in the spread between the loan and dividend rate with this primarily driven by a fall in the loan rate. Given that the adoption of a website, albeit with limited functionality, translates into cost benefits this augurs well for the current restructuring process underway for Irish credit unions which has as one of its objectives the upgrade of credit union ICT sophistication.