Sex-based differences in the adaptive value of social behavior contrasted against morphology and environment.

The adaptive nature of sociality has long been a central question in ecology and evolution. However, the relative importance of social behavior for fitness, compared to morphology and environment, remains largely unknown. We assessed the importance of sociality for fitness (lamb production and survival) in a population of mark6d bighorn sheep (Ovis canadensis) over 16 years (n = 1022 sheep-years). We constructed social networks from observations (n = 38,350) of group membership (n = 3150 groups). We then tested whether consistent individual differences in social behavior (centrality) exist and evaluated their relative importance compared to factors known to affect fitness: mass, age, parental effects, and population density. Sheep exhibited consistent individual differences in social centrality. Controlling for maternal carryover effects and age, the positive effect of centrality in a social network on adult female lamb production and survival was equal or greater than the effect of body mass or population density. Social centrality had less effect on male survival and no effect on adult male lamb production or lamb survival. Through its effect on lamb production and survival, sociality in fission-fusion animal societies may ultimately influence population dynamics equally or more than morphological or environmental effects.

Disruptive viability selection on adult exploratory behaviour in eastern chipmunks.

Heterogeneous forces of selection associated with fluctuating environments are recognized as important factors involved in the maintenance of inter-individual phenotypic variance within populations. Consistent behavioural differences over time and across situations (e.g. personality) are increasingly cited as examples of individual variation observed within populations. However, the suggestion that heterogeneous selective pressures target different animal personalities remains largely untested in the wild. In this 5-year study, we investigated the dynamics of viability selection on a personality trait, exploration, in a population of eastern chipmunks (Tamias striatus) experiencing substantial seasonal variations in weather conditions and food availability associated with masting trees. Contrary to our expectations, we found no evidence of fluctuating selection on exploration. Instead, we found strong disruptive viability selection on adult exploration behaviour, independent of seasonal variations. Individuals with either low or high exploration scores were almost twice as likely to survive over a 6-month period compared with individuals with intermediate scores. We found no evidence of viability selection on juvenile exploration. Our results highlight that disruptive selection might play an important role in the maintenance of phenotypic variance of wild populations through its effect on different personality types across temporally varying environmental conditions.

Low heritabilities, but genetic and maternal correlations between red squirrel behaviours.

Consistent individual differences in behaviour, and behavioural correlations within and across contexts, are referred to as animal personalities. These patterns of variation have been identified in many animal taxa and are likely to have important ecological and evolutionary consequences. Despite their importance, genetic and environmental sources of variation in personalities have rarely been characterized in wild populations. We used a Bayesian animal model approach to estimate genetic parameters for aggression, activity and docility in North American red squirrels (Tamiasciurus hudsonicus). We found support for low heritabilities (0.08-0.12), and cohort effects (0.07-0.09), as well as low to moderate maternal effects (0.07-0.15) and permanent environmental effects (0.08-0.16). Finally, we found evidence of a substantial positive genetic correlation (0.68) and maternal effects correlation (0.58) between activity and aggression providing evidence of genetically based behavioural correlations in red squirrels. These results provide evidence for the presence of heritable variation in red squirrel behaviour, but also emphasize the role of other sources of variation, including maternal effects, in shaping patterns of variation and covariation in behavioural traits.

Phenotypic variation in urban environments: mechanisms and implications.

In the past decade, numerous studies have explored how urbanisation affects the mean phenotypes of populations, but it remains unknown how urbanisation impacts phenotypic variation, a key target of selection that shapes, and is shaped by, eco-evolutionary processes. Our review suggests that urbanisation may often increase intraspecific phenotypic variation through several processes; a conclusion aligned with results from our illustrative analysis on tit morphology across 13 European city/forest population pairs. Urban-driven changes in phenotypic variation will have immense implications for urban populations and communities, particularly through urbanisation's effects on individual fitness, species interactions, and conservation. We call here for studies that incorporate phenotypic variation in urban eco-evolutionary research alongside advances in theory.

Evidence of multiple paternity and mate selection for inbreeding avoidance in wild eastern chipmunks.

Mate selection for inbreeding avoidance is documented in several taxa. In mammals, most conclusive evidence comes from captive experiments that control for the availability of mates and for the level of genetic relatedness between mating partners. However, the importance of mate selection for inbreeding avoidance as a determinant of siring success in the wild has rarely been addressed. We followed the reproduction of a wild population of eastern chipmunks (Tamias striatus) during five breeding seasons between 2006 and 2009. Using molecular tools and parentage assignment methods, we found that multiple paternity (among polytocous litters) varied from 25% in an early-spring breeding season when less than a quarter of females in the population were reproductively active to 100% across three summer breeding seasons and one spring breeding season when more than 85% of females were reproductively active. Genetically related parents were common in this population and produced less heterozygous offspring. Furthermore, litters with multiple sires showed a higher average relatedness among partners than litters with only a single sire. In multiply sired litters, however, males that were more closely related to their partners sired fewer offspring. Our results corroborate findings from captive experiments and suggest that selection for inbreeding avoidance can be an important determinant of reproductive success in wild mammals.

Genetic correlation between resting metabolic rate and exploratory behaviour in deer mice (Peromyscus maniculatus).

According to the 'pace-of-life' syndrome hypothesis, differences in resting metabolic rate (RMR) should be genetically associated with exploratory behaviour. A large number of studies reported significant heritability for both RMR and exploratory behaviour, but the genetic correlation between the two has yet to be documented. We used a quantitative genetic approach to decompose the phenotypic (co)variance of several metabolic and behavioural measures into components of additive genetic, common environment and permanent environment variance in captive deer mice. We found significant additive genetic variance for two mass-independent metabolic measures (RMR and the average metabolic rate throughout the respirometry run) and two behavioural measures (time spent in centre and distance moved in a novel environment). We also detected positive additive genetic correlation between mass-independent RMR and distance moved (r(A) = 0.78 ± 0.23). Our results suggest that RMR and exploratory behaviour are functionally integrated traits in deer mice, providing empirical support for one of the connections within the pace-of-life syndrome hypothesis.

Male personality, life-history strategies and reproductive success in a promiscuous mammal.

Recent theoretical work suggests that personality is a component of life history, but links between personality and either age-dependent reproductive success or life-history strategy are yet to be established. Using quantitative genetic analyses on a long-term pedigree we estimated indices of boldness and docility for 105 bighorn sheep rams (Ovis canadensis), born between 1983 and 1999, and compared these indices to their reproductive history from 2 years of age until death. Docility and boldness were highly heritable and negatively genetically correlated. Docile and bold rams survived longer than indocile and shy rams. Docility and boldness had a weak negative effect on reproductive success early in life, but a strong positive effect on older rams. Our findings highlight an important role of personality on reproductive success and suggest that personality could be an important component of life-history strategy.

Animal temperament and human disturbance: implications for the response of wildlife to tourism.

Studies on the response of wildlife to human disturbance generally focus on demographic changes or on physiological and behavioural modifications directly related to stress response. Yet fewer studies have explored whether the distribution of individual animals in response to human disturbance is influenced by temperament. Temperament represents the consistency of responses of individuals in reaction to novel or challenging situations. Individuals are thus assumed to express highly consistent behaviour-hormonal response under specific stress conditions. In this study, we investigate the relations between exploration, grooming-scanning continuum, emotionality, and docility of individual Eastern chipmunks (Tamias striatus) and location of their burrow respective to frequentation by humans. We then assess the relationship between cortisol accumulated in the hair and both temperament and frequentation by humans. Explorative or docile chipmunks were more common in frequented areas. Hair cortisol increased with docility, but was not related to human frequentation. These results indicate that temperament may cause animals to distribute themselves in a non-random way in response to human disturbance. Integrating temperament into studies of the stress response of wildlife to humans could therefore help us understand the impact of tourism on wildlife.

Investigation of a stripline transmission line structure for gyromagnetic nonlinear transmission line high power microwave sources.

A stripline gyromagnetic nonlinear transmission line (NLTL) was constructed out of yttrium iron garnet ferrite and tested at charge voltages of 35 kV-55 kV with bias fields ranging from 10 kA/m to 20 kA/m. Typically, high power gyromagnetic NLTLs are constructed in a coaxial geometry. While this approach has many advantages, including a uniform transverse electromagnetic (TEM) mode, simple interconnection between components, and the ability to use oil or pressurized gas as an insulator, the coaxial implementation suffers from complexity of construction, especially when using a solid insulator. By moving to a simpler transmission line geometry, NLTLs can be constructed more easily and arrayed on a single substrate. This work represents a first step in exploring the suitability of various transmission line structures, such as microstrips and coplanar waveguides. The resulting high power microwave (HPM) source operates in ultra high frequency (UHF) band with an average bandwidth of 40.1% and peak rf power from 2 MW to 12.7 MW.

Characteristics of a four element gyromagnetic nonlinear transmission line array high power microwave source.

In this paper, a solid-state four element array gyromagnetic nonlinear transmission line high power microwave system is presented as well as a detailed description of its subsystems and general output capabilities. This frequency agile S-band source is easily adjusted from 2-4 GHz by way of a DC driven biasing magnetic field and is capable of generating electric fields of 7.8 kV/m at 10 m correlating to 4.2 MW of RF power with pulse repetition frequencies up to 1 kHz. Beam steering of the array at angles of ±16.7° is also demonstrated, and the associated general radiation pattern is detailed.

Material selection of a ferrimagnetic loaded coaxial delay line for phasing gyromagnetic nonlinear transmission lines.

Implementing nonlinear transmission line (NLTL) technology in the design of a high power microwave source has the benefits of producing a comparatively small and lightweight solid-state system where the emission frequency is easily tuned. Usually, smaller in physical size, single NLTLs may produce significantly less power than its vacuum based counterparts. However, combining individual NLTL outputs electrically or in free-space is an attractive solution to achieve greater output power. This paper discusses a method for aligning a four element NLTL antenna array with coaxial geometry using easily adjustable temporal delay lines. These delay lines, sometimes referred to as pulse shock lines or pulse sharpening lines, are placed serially in front of the main NLTL line. The propagation velocity in each delay line is set by the voltage amplitude of an incident pulse as well as the magnetic field bias. Each is adjustable although for the system described in this paper, the voltage is held constant while the bias is changed through applying an external DC magnetic field of varying magnitude. Three different ferrimagnetic materials are placed in the temporal delay line to evaluate which yields the greatest range of electrical delay with the least amount of variability from consecutive shots.

Estimating genetic correlations in natural populations in the absence of pedigree information: accuracy and precision of the Lynch method.

Usually, genetic correlations are estimated from breeding designs in the laboratory or greenhouse. However, estimates of the genetic correlation for natural populations are lacking, mostly because pedigrees of wild individuals are rarely known. Recently Lynch (1999) proposed a formula to estimate the genetic correlation in the absence of data on pedigree. This method has been shown to be particularly accurate provided a large sample size and a minimum (20%) proportion of relatives. Lynch (1999) proposed the use of the bootstrap to estimate standard errors associated with genetic correlations, but did not test the reliability of such a method. We tested the bootstrap and showed the jackknife can provide valid estimates of the genetic correlation calculated with the Lynch formula. The occurrence of undefined estimates, combined with the high number of replicates involved in the bootstrap, means there is a high probability of obtaining a biased upward, incomplete bootstrap, even when there is a high fraction of related pairs in a sample. It is easier to obtain complete jackknife estimates for which all the pseudovalues have been defined. We therefore recommend the use of the jackknife to estimate the genetic correlation with the Lynch formula. Provided data can be collected for more than two individuals at each location, we propose a group sampling method that produces low standard errors associated with the jackknife, even when there is a low fraction of relatives in a sample.

Lifetime selection on heritable life-history traits in a natural population of red squirrels.

Despite their importance in evolutionary biology, heritability and the strength of natural selection have rarely been estimated in wild populations of iteroparous species or have usually been limited to one particular event during an organism's lifetime. Using an animal-model restricted maximum likelihood and phenotypic selection models, we estimated quantitative genetic parameters and the strength of lifetime selection on parturition date and litter size at birth in a natural population of North American red squirrels, Tamiasciurus hudsonicus. Litter size at birth and parturition date had low heritabilities (h2 = 0.15 and 0.16, respectively). We considered potential effects of temporal environmental covariances between phenotypes and fitness and of spatial environmental heterogeneity in estimates of selection. Selection favored early breeders and females that produced litter sizes close to the population average. Stabilizing selection on litter size at birth may occur because of a trade-off between number of offspring produced per litter and offspring survival or a trade-off between a female's fecundity and her future reproductive success and survival.

Xanthogranulomatous gastritis: association with xanthogranulomatous cholecystitis.

A case of xanthogranulomatous inflammation of the gastric wall is reported. The lesion was associated with adherent xanthogranulomatous cholecystitis and simulated, clinically, a malignant neoplasm. Histologically, foamy histiocytes, multi-nucleated giant cells, other inflammatory cells, fibrous reaction with spindle cells and cholesterol clefts were found.

Heritability of body mass varies with age and season in wild bighorn sheep

Heritabilities (h2) of body mass at different ages and seasons were estimated using offspring-mother regression and restricted maximum likelihood (REML) methods for bighorn sheep on Ram Mountain, Alberta. Both methods resulted in similar estimates of h2 for adults, but for lambs and yearlings heritability was underestimated by offspring-mother regression relative to REML, possibly because of higher maternal-effects bias for offspring-mother regression. Heritabilities of body mass in bighorn were similar to published estimates for domestic sheep. Heritability estimated by offspring-mother regression increased after 2 years of age. The REML method suggested that heritability was moderate for lambs and yearlings, very low at 2 years of age, and increased afterwards. The increase in heritability with age was attributed to declining negative maternal effects. Very low h2 estimates at 2 years of age, obtained with both methods, appeared to be caused by a combination of high environmental variance and very low genetic variance. Body mass of bighorn sheep has a pronounced seasonal cycle, and h2 was lower in June than in September for 2-year-olds and older sheep, and associated with both lower VA and higher VE in spring.

Ductal adenoma of the breast. An immunohistochemical study of five cases.

The immunohistochemical features of 5 ductal adenomas of the breast were investigated. The tumours were composed by tubular glands lined by cells with both luminal and basal/myoepithelial immunophenotypes. Tubules were encircled by an intact basement membrane as demonstrated by staining for laminin and type IV collagen. Areas of dense fibrosis, a usual finding in these lesions, stained for fibronectin, type III collagen and contained vimentin and actin positive spindle cells, consistent with myofibroblasts. These observations confirm a double epithelial and myoepithelial differentiation in these lesions and seem to support the suggestion that ductal adenomas result from sclerosis of ductal papillomas.

Nursing behaviour and mother-lamb relationships in mouflon under fluctuating population densities.

The mouflon population of the subantarctic Kerguelen archipelago undergoes periodic die-offs and shows marked interannual variations in density. This situation allowed us to investigate nursing behaviour and mother-lamb relationships under contrasting population densities during three successive years, centred on a crash year (1992). Poor diet quality and high neonatal mortality characterised the pre-crash year (1991). During the crash year, neonatal mortality was high at the onset of the lambing season, but young survival increased rapidly when environmental conditions improved. Diet quality was high and neonatal mortality was reduced in 1993 (post-crash). Total suckling duration was constant between years, but the higher frequency of unsuccessful suckling attempts and allosuckling attempts in 1991 suggested a limitation of maternal expenditure for that year. Lambs grazed earlier, played less, spent less time resting and had lower growth rates in 1991 than in other years. These results suggest a greater mother-offspring conflict when food resources were limited. Adverse environmental conditions may affect females' condition and constrain maternal expenditure. However, maternal expenditure increased as soon as diet quality improved, suggesting that females adjusted maternal care by tracking environmental conditions.

The basement membranes in sarcomatoid carcinomas. An immunohistochemical study.

AIMS: Eight sarcomatoid carcinomas from various anatomical locations were investigated by immunohistochemical staining to laminin, type IV collagen and heparan sulfate proteoglycan, to study the characteristics of basement membranes at the interface between carcinomatous and sarcomatous tissues. METHODS: Paraffin wax embedded tissue sections from representative tumor samples have been stained with specific antibodies, using the peroxidase-antiperoxidase technique. RESULTS: In all cases several interruptions or discontinuities of the basement membrane staining pattern were seen. In 4 cases, larger defects or complete loss of staining was also noted. At these places, the boundaries between carcinomatous and sarcomatous tissue were often blurred. CONCLUSIONS: Disruption and loss of basement membranes at interface between carcinomatous and sarcomatous tissues is a frequent finding in sarcomatoid carcinomas. These changes could be consistent with an epithelial origin of the sarcomatous component in these tumors by means of an epithelial-mesenchymal conversion mechanism.

Human dirofilariasis in Italy: a new case in the spermatic cord.

A new case of human dirofilariasis associated with Dirofilaria (Nochtiella) repens (Nematoda, Filarioidea, Onchocercidae) located in the spermatic cord is reported in a 71-year-old man from the province of Campobasso (Central Italy). When clinical signs pointed to a testicular tumor, a monolateral orchifuniculectomy was performed. According to the scientific literature, this case appears to be exceptional in its location, being only the eighth such case recorded in the world until now. The nematode, as well as the presence of vectors suitable for its transmission, had already been observed both in dogs and in humans (3 subcutaneous cases) in the same geographical area.

[Late pancreatic metastasis of renal carcinoma. Description of 2 cases and review of the literature]. / Metastasi pancreatica tardiva di carcinoma renale. Descrizione di due casi e revisione della letteratura.

Authors report two cases of pancreatic metastasis from renal clear cell carcinoma, discovered in a 62 years-old-man and in a 73 years-old woman, respectively 17 and 11 years after undergoing curative nephrectomy for primary tumor. Immunological forces and slow doubling times of tumor may explain this type of late recurrence, whereas, the endocrine status is lacking in importance. The risk of a recurrence of tumour ten years or later after nephrectomy suggests a lifelong follow-up of patients with an history of renal cell carcinoma.