Similar Body Size Research Articles

Medium-Term Pulmonary Function Test After Thoracoscopic Lobectomy and Segmentectomy for Congenital Lung Malformation: A Comparative Study With Normal Control.

Purpose: This study aimed to compare the outcomes and pulmonary function test (PFT) of thoracoscopic segmentectomy and lobectomy in infants with congenital lung malformation and study the result of PFT on a medium-term basis.Methods: The clinical data of 19 infants with congenital lung malformation who underwent thoracoscopic surgery in our hospital from January 2018 to March 2019 were retrospectively studied; these infants were paired with another 19 infants who underwent thoracoscopic lobectomy during the same period using propensity score matching. Age-matched healthy individuals with similar body sizes were recruited for PFT as the control group. Patient characteristics, postoperative PFT, and outcomes were extracted for statistical analysis.Results: The average length of hospital stay did not significantly differ between segmentectomy and lobectomy groups. The segmentectomy group had more chest tube drainage than the lobectomy group. PFT 1 month after the operation showed that the tidal volume of the lobectomy group was lower than that of the segmentectomy group. Time to peak expiratory flow/time of expiration and peak flow/terminal airway velocity (V25%) indicated small airway dysfunction in the lobectomy group, and no obvious abnormalities were found in “time of inspiratory/time of expiration” in either group. Reexamination of pulmonary function 2 years after the operation showed that the small airway function of the segmentectomy group returned to normal, and no significant difference in pulmonary function was noted among the three groups.Conclusion: The short-term pulmonary function recovery was better after segmentectomy than after lobectomy. Patients who underwent thoracoscopic lobectomy and segmentectomy have normal lung function 2 years after the operation.

Seasonal occurrence of Japanese pygmy octopus Octopus parvus in the intertidal zone

The Japanese pygmy octopus, Octopus parvus, is a small octopus that commonly occurs along the coast of southern Japan; however, the ecological information is limited. This study investigated the annual seasonal occurrence of O. parvus in the intertidal zone of Fukue Island, Nagasaki, Japan, and examined its growth, maturation, and feeding habits. We found 140 individuals in the intertidal zone from August to January, and zero from March to July. During the emergence period, they appear to move from the high to low intertidal zone, and subsequently migrate to the subtidal zone. During low tide at night in the intertidal zone, we observed that the octopuses actively captured and fed on prey, such as fish, crabs, hermit crabs, shrimp, gastropods, and bivalves. The body size of collected individuals increased significantly from summer to winter. Both males and females were found to be characterized by similar body sizes and growth, although gonadal development occurred earlier in males. However, no mating or brooding behaviors were observed during the course of the study. Our observations thus indicate that O. parvus uses intertidal zones as feeding grounds for rapid growth and maturation, and may thereafter move to the subtidal zone for spawning.

Plasticity and flexibility in the anti-predator responses of treefrog tadpoles

Tadpoles can respond to perceived predation risk by adjusting their life history, morphology, and behavior in an adaptive way. Adaptive phenotypic plasticity can evolve by natural selection only if there is variation in reaction norms and if this variation is, at least in part, heritable. To provide insights into the evolution of adaptive phenotypic plasticity, we analyzed the environmental and parental components of variation in predator-induced life history (age and size at metamorphosis), morphology (tail depth), and behavior of Italian treefrog tadpoles (Hyla intermedia). Using an incomplete factorial design, we raised tadpoles either with or without caged predators (dragonfly larvae, gen. Aeshna) and, successively, we tested them in experimental arenas either with or without caged predators. Results provided strong evidence for an environmental effect on all three sets of characters. Tadpoles raised with caged predators (dragonfly larvae, gen. Aeshna) metamorphosed earlier (but at a similar body size) and developed deeper tails than their fullsib siblings raised without predators. In the experimental arenas, all tadpoles, independent of their experience, flexibly changed their activity and position, depending on whether the cage was empty or contained the predator. Tadpoles of the two experimental groups, however, showed different responses: those raised with predators were always less active than their predator-naive siblings and differences slightly increased in the presence of predators. Besides this strong environmental component of phenotypic variation, results provided evidence also for parental and parental-by-environment effects, which were strong on life-history, but weak on morphology and behavior. Interestingly, additive parental effects were explained mainly by dams. This supports the hypothesis that phenotypic plasticity might mainly depend on maternal effects and that it might be the expression of condition-dependent mechanisms.Significance statementAnimals, by plastically adjusting their phenotypes to the local environments, can often sensibly improve their chances of survival, suggesting the hypothesis that phenotypic plasticity evolved by natural selection. We test this hypothesis in the Italian treefrog tadpoles, by investigating the heritable variation in the plastic response to predators (dragonfly larvae). Using an incomplete factorial common-garden experiment, we showed that tadpoles raised with predators metamorphosed earlier (but at similar body size), developed deeper tails, and were less active than their siblings raised without predators. The plastic response varied among families, but variation showed a stronger maternal than paternal component. This suggests that plasticity might largely depend on epigenetic factors and be the expression of condition-dependent mechanisms.

Response to exploitation and life history characteristics of two Acanthurus fish species with divergent mating behaviour along the Kenyan coastline

In reef ecosystems, vulnerability to exploitation is species-specific and may vary with natural abundance, life history characteristics, or ease of capture. Therefore, understanding the growth parameters and exploitation rate of individual species is important, because application of a uniform management strategy in species with different responses or vulnerability to exploitation can be inappropriate. In this study, growth parameters (length at first maturity, length at optimum yield, asymptotic length, growth constant, and growth performance index) and mortality from two Acanthurus fish species were compared, to deduce whether differences in species-specific traits (spawning mating behaviour) could lead to differences in exploitation rate. Despite comparable estimates of the von Bertalanffy asymptotic length (L∞) in the two species [A. triostegus (27.9–29.6) and A. leucosternon (26.1–27.4)], the growth coefficient constant (K) estimates for A. triostegus (0.85–1.23) were almost three to fivefold higher than those of A. leucosternon (0.29–0.38), suggesting that A. triostegus attains its maximum length faster than A. leucosternon. Length at first maturity (Lm), length at optimum yield (Lopt), and exploitation rate (E) were also different between the two species, specifically indicating exploitation beyond the sustainable yield in A. triostegus but not in A. leucosternon. The finding of a higher exploitation rate in A. triostegus as compared to A. leucosternon could suggest that regardless of similar body sizes, the former is more susceptible to exploitation.

The effects of warming on red blood cell carbonic anhydrase activity and respiratory performance in a marine fish

Measures of fitness are valuable tools to predict species' responses to environmental changes, like increased water temperature. Aerobic scope (AS) is a measure of an individual's capacity for aerobic processes, and frequently used as a proxy for fitness. However, AS is complicated by individual variation found not only within a species, but within similar body sizes as well. Maximum metabolic rate (MMR), one of the factors determining AS, is constrained by an individual's ability to deliver and extract oxygen (O2) at the tissues. Recently, data has shown that red blood cell carbonic anhydrase (RBC CA) is rate-limiting for O2 delivery in red drum (Sciaenops ocellatus). We hypothesized increased temperature impacts MMR and RBC CA activity in a similar manner, and that an individual's RBC CA activity drives individual variation in AS. Red drum were acutely exposed to increased temperature (+6 °C; 22 °C to 28 °C) for 24 h prior to exhaustive exercise and intermittent-flow respirometry at 28 °C. RBC CA activity was measured before temperature exposure and after aerobic performance. Due to enzymatic thermal sensitivity, acute warming increased individual RBC CA activity by 36%, while there was no significant change in the control (22 °C) treatment. Interestingly, average MMR of the acute warming treatment was 36% greater than that of control drum. However, we found no relationships between individual RBC CA activity and their respective MMR and AS at either temperature. While warming similarly affects RBC CA activity and MMR, RBC CA activity is not a predictor of individual MMR.

Do exotic poeciliids affect the distribution or trophic niche of native fishes? Absence of evidence from Hong Kong streams

Abstract Exotic poeciliids have been reported to reduce abundance and richness of native fishes and, more generally, constrain the trophic niches of native counterparts. However, understanding of the consequences of poeciliids on native fishes in tropical streams is limited. We conducted a survey of lowland streams in Hong Kong during 2018–19 to document the prevalence of poeciliids and look for signs that they had affected the distribution of native fishes. Overall, 31 native and 15 exotic fishes were recorded during the survey. Exotics occurred at 37 out of 45 survey sites, with poeciliids present at 35 sites. Richness of poeciliids or other exotic fishes had no correlation with the number of native species at each site. Moreover, native fish assemblages appeared unaffected by poeciliids, which might reflect a legacy of stream pollution. By comparing nine streams where the presence and composition of poeciliids varied, we investigated whether the mosquitofish (Gambusia affinis) alone, and in combination with the guppy (Poecilia reticulata), swordtail (Xiphophorus hellerii), and variable platy (Xiphophorus variatus), affected the trophic niche of native half‐banded barb (Puntius semifasciolatus: Cyprinidae) which has a similar body size to the poeciliids, as quantified by gut content and stable‐isotope analysis. We also tested whether the trophic niche of the mosquitofish was affected by the three other poeciliids. Gut‐content analysis indicated that the half‐handed barb fed on aquatic invertebrates, while the mosquitofish ate mainly terrestrial insects. The three other poeciliids were predominately primary consumers. The mosquitofish, alone or in combination with other poeciliids, had no detectable effects on the dietary or isotopic niche of the barb, nor was the niche of the mosquitofish influenced by the presence of other poeciliids. Limited dietary overlap and differences in microhabitat use were likely to account for the absence of a detectable niche shift by the barb where poeciliids were present.

The Perception of Malaysian Rural and Urban Indigenous Women on Body Image

This study investigates the perception of body image among indigenous women in Peninsular Malaysia. Using a sample drawn from urban (n=38) and rural (n=21) settings, the study engages participants who are more or less socio-economically acculturated to mainstream society in order to explore different attitudes to body image, and anxiety level about social physique between rural and urban women. Rural indigenous women registered a higher level of body dissatisfaction than their urban counterparts. However, there was no significant difference in attitudes towards body image between indigenous women in both locations. Due to a degree of presumed acculturation to western ideals of body image, urban indigenous women who were not underweight showed a higher anxiety level concerning their physique than those from rural areas with a similar body size. It was also found that a higher level of body dissatisfaction correlated with a poorer body image among indigenous women in Malaysia.

Do predatory adult odonates estimate their adult prey odonates’ body size and dispersal ability to proceed with a successful attack?

Predator-prey encounters are one of the most challenging behaviors that animals engage in and play a key role in structuring trophic linkages within food webs. Empirical studies suggest that predators (except pathogens, parasites, and parasitoids) tend to be larger in body size and have better dispersal ability than their prey items; however, when predators prey upon members of the same taxonomic group, it is unclear whether such relationships exist between predators and their prey items since both groups may have similar body sizes and dispersal abilities. Adult odonates can be used to test this as they prey upon other odonates within the same suborder, family, genus or species, although such records are uncommon. Using a dataset collected from Sri Lanka and India from 2012 to 2020, this study identified three types of predation behaviors between two suborders of Odonata, i.e., (i) Anisoptera (dragonflies) prey upon Anisoptera, (ii) Anisoptera prey upon Zygoptera (damselflies), and (iii) Zygoptera prey upon Zygoptera. There was no evidence of Anisoptera predation by Zygoptera. Study results showed strong evidence that there is a significant difference in body size (i.e., body length) and dispersal ability (i.e., hind-wing length) between adult predatory odonates and adult prey odonates for all three types of predations. This may indicate that predatory odonates estimate other odonate prey precisely to proceed with a successful attack.

Sparring dynamics and individual laterality in male South African giraffes

AbstractSparring by male giraffes has been commonly reported since its first description in 1958 and is believed to play a role in establishing male dominance hierarchies. However, despite being often documented, quantitative investigations of sparring behaviour are currently lacking. Here, we investigate the factors affecting the frequency, duration and intensity of sparring bouts in a population of giraffes Giraffa camelopardalis giraffa living on a private fenced reserve in Limpopo, South Africa. We show that sparring bouts were most frequently observed in young adults, and between males that were more evenly matched in size. Sparring bouts between males of similar body size were also characterised by being of high intensity and of short duration. Taken together, these results support the suggestion that sparring functions principally to provide maturing males a means of testing their competitive ability without escalating to full‐scale fights. Additionally, mature bulls intervened on young adults possibly to disable any winner effect achieved by the latter, with the most dominant bull being responsible for the majority of interventions. For the first time, we also show that individuals displayed strong laterality when engaged in sparring: individuals consistently preferred delivering blows from either their left or right side, and these preferences dictated the orientation of sparring bouts (whether head‐to‐head or head‐to‐tail). Lastly, we show that sparring displayed a seasonal peak which coincided with the onset of the wet season and possibly reflected the increased aggregation of males at this time. A more nuanced understanding of how social and environmental factors shape interactions among individuals, such as sparring, will improve our understanding and management of this charismatic animal.

Quantifying the effects of intraspecific variation on predator feeding rates through nonlinear averaging

Abstract Theory suggests that intraspecific trait variation will alter species interaction strengths through nonlinear averaging when interaction strengths are nonlinear functions of individuals' traits. This effect is expected to be widespread, yet what factors mediate its magnitude in nature and hence its potential effects on ecosystems and communities are unclear. We sought to quantify how nonlinear predator functional responses, variation in prey densities and counteracting variation in attack rates and handling times among predator individuals of similar body size alter their population‐level feeding rates through nonlinear averaging in a natural system, and to determine the processes influencing the net magnitude of this effect. We used a field caging experiment in the rocky intertidal of Oregon, USA to quantify attack‐rate variation and feeding rates of the whelk Nucella ostrina on its barnacle and mussel prey. We also used empirically parameterized simulations to examine the effects of handling‐time variation among individuals on population‐level feeding rates. Within cages, individual attack‐rate variation reduced population‐level whelk feeding rates. However, the magnitude of this reduction differed among prey species and cages depending on cage‐specific magnitudes of attack‐rate variation and functional‐response nonlinearity. The inferred effects of handling‐time variation among individuals were of smaller magnitude than those of attack‐rate variation, yet counteracted them to cause a net weakening of the effect of individual attack‐rate variation on population‐level feeding rates. Across cages, attack‐rate and prey‐density variation had non‐additive effects that produced greater feeding‐rate reductions at the experiment scale relative to the cage scale. Our results indicate that the effects of trait variation via nonlinear averaging depend critically on the features of systems that determine the magnitudes of nonlinearities and trait variation. Because of counteracting trait variation, nonlinear‐averaging effects may be quite complex, involving both the variances and covariances of all traits and environmental variables influencing the ecological process of interest. A free Plain Language Summary can be found within the Supporting Information of this article.

Study on contour feathers growth of White-rumped Shama during fledgling phase

White-rumped Shama (Copsychus malabaricus) has become a favorite pet among Indonesian bird keepers lately. A champion bird with beautiful chirps and colours would be valued high. There are very limited scientific information on its species, and this study results will enrich the biological data. The purpose of this study was to trace and record white-rumped shama contour feathers growth including feather types and changes of size during fledgling phase. There were 8 mixed sex chicks (a crossbreed of Medan x North Bengkulu) aged 30 days with similar body weight and size used in this study. Daily individual observation on parameters were conducted from day-1 of nurturing until chick’s individual first moulting day. Observation results showed that contour feathers on white-rumped shama chicks body which easily to observed were retrices and remiges. Then, based on anatomical feather during pledgling phase on chick’s part of forehead, nape, chest, back, wing and tail we recorded 3 types of feathers which were filoplumae, plumulae and plumae. Average of retrices length and width in tail were 69.62 mm and 11.10 mm per chick, and average of remiges primarie length and width in wing were 63.32 mm and 9.74 mm per chick, respectively. Researchers found that as similar as to other species of aves, the size of White-rumped Shama retrices is longer and wider than remiges.

Carpal Shape Variation Between Pan and Gorilla Mirrors That of Other Mammals With Similar Body Size Differences

Chimpanzees, bonobos (Pan), and gorillas (Gorilla) are the only extant knuckle-walking primates. Two hypotheses have been proposed to explain the evolution of knuckle-walking in Pan and Gorilla. The knuckle-walking hypothesis holds that the last common ancestor of Pan, Gorilla, and Homo knuckle-walked. The alternative hypothesis holds that Pan and Gorilla evolved knuckle-walking independently. One unresolved issue is that, despite sharing knuckle-walking as a common locomotor mode, Pan and Gorilla exhibit different carpal morphologies. This morphological variation has been used to support the theory that Pan and Gorilla evolved knuckle-walking independently. To date, however, little work has focused on the effect of body mass on this functional complex. Here, we compare shape changes in the carpals of Pan and Gorilla to those of other quadrupedal mammals with similar body size differences. If morphological trends in the carpus of Pan and Gorilla mirror those of other mammals with similar body mass variation, then carpal variation in African apes may be attributed to differences in body mass, rather than the independent evolution of knuckle-walking. More specifically, we hypothesize that the carpals of high body mass taxa will be relatively proximo-distally shorter and medio-laterally/antero-posteriorly wider than those of low body mass taxa. The capitate, hamate, and triquetrum of high and low body mass taxa from the mammalian families Hominidae, Cercopithecidae, Bovidae, Canidae, and Myrmecophagidae were surface scanned. A weighted spherical harmonic (SPHARM) analysis was used to quantify the shape of each carpal. During the SPHARM analysis, surface models were mapped onto the surface of a sphere, and then decomposed into a weighted sum of spherical harmonic functions. Shape variation of each carpal (within each mammalian family) was summarized using a principal component analysis (PCA) of coefficients from spherical harmonic functions. The log-centroid size of each surface model was added to each PCA to determine the effect of size on shape variation. Shape changes were visualized by comparing surface models of the average specimen from species with the highest and lowest body mass within each family. Species separate by body mass in all PC plots, and comparison of average specimen surface models indicates that across all mammalian families included in the analysis, the capitate, hamate, and triquetrum exhibit similar shape changes between high and low body mass taxa (i.e., the carpals of high body mass taxa are proximo-distally shorter and medio-laterally wider than those of low body mass taxa). These distinctions are likely caused by the need to accommodate the higher forelimb loading associated with an increase in body mass. Furthermore, because these patterns of shape change are seen in the carpals of multiple mammalian families, morphological variation in the carpals of chimpanzees and gorillas is more likely due to differences in body size than the independent evolution of knuckle-walking.

Porcine models of acute kidney injury.

Pigs represent a potentially attractive model for medical research. Similar body size and physiological patterns of kidney injury that more closely mimic those described in humans make larger animals attractive for experimentation. Using larger animals, including pigs, to investigate the pathogenesis of acute kidney injury (AKI) also serves as an experimental bridge, narrowing the gap between clinical disease and preclinical discoveries. This article compares the advantages and disadvantages of large versus small AKI animal models and provides a comprehensive overview of the development and application of porcine models of AKI induced by clinically relevant insults, including ischemia-reperfusion, sepsis, and nephrotoxin exposure. The primary focus of this review is to evaluate the use of pigs for AKI studies by current investigators, including areas where more information is needed.

Social and spatial patterns of two Afromontane crag lizards (Pseudocordylus spp.) in the Maloti‐Drakensberg Mountains, South Africa

AbstractUnderstanding the evolution of vertebrate sociality requires comparative data on social associations across the vertebrate phylogeny. In the case of group‐living lizards (i.e. species that live in stable social aggregations often associated with a shared resource), most work has focused on the Egerniinae in Australia, resulting in a taxonomic and geographic skew to our understanding of reptile sociality. The African cordylid lizards (Cordylidae) are also a promising system to study the evolution of sociality because grouping behaviour varies across the clade. Here, we studied the conspecific grouping behaviour of two crag lizards, Pseudocordylus langi and P. melanotus subviridis that occur at high elevations in the Maloti‐Drakensberg Mountains of South Africa. To better understand their social organisation and mating system, we also present data on their spatial distribution, sexual dimorphism, and bite force. Both Pseudocordylus spp. were sexually dimorphic in morphology (males had larger heads than females of similar body size), colouration (males were more colourful) and female P. langi had a weaker bite force than males. Both P. langi and P. m. subviridis were associated with rocky habitat on the mountainside (e.g. cliffs, rock buttresses, and rock outcrops) and both were spaced apart and rarely in groups (79% of P. langi and 90% of P. m. subviridis were observed alone). Based on our findings, we hypothesise that both Pseudocordylus spp. have a territorial social structure and a polygynous mating system. This novel natural history information about crag lizards supports the assertion that Cordylidae is another model system for examining the evolution of sociality.

Sex-Specific Population Differences in Resting Metabolism Are Associated with Intraspecific Variation in Sexual Size Dimorphism of Brown Anoles.

AbstractSexual size dimorphism can vary in direction and magnitude across populations, but the extent to which such intraspecific variation is associated with sex and population differences in underlying metabolic processes is unclear. We compared resting metabolic rates (RMRs) of brown anole lizards (Anolis sagrei) from two island populations in the Bahamas (Eleuthera and Great Exuma) that differ in the magnitude of male-biased sexual size dimorphism. Whereas females from each population exhibit similar growth rates and body sizes, males from Great Exuma grow more quickly and attain larger body sizes than males from Eleuthera. We found that these population differences in growth of males persisted in captivity. Therefore, we predicted that males from each population would differ in RMR, whereas females would not. Consistent with this prediction, we found that RMR of males from Eleuthera was higher than that of males from Great Exuma, particularly at higher temperatures. As predicted, RMR of females did not differ between populations. Despite this apparent sex-specific trade-off between growth rate and RMR at the population level, we found a positive relationship between growth rate and RMR at the individual level. The fact that Great Exuma males maintain lower RMR than Eleuthera males, despite their greater absolute growth rates and the positive relationship between RMR and growth rate across individuals, suggests that Great Exuma males may have lower baseline metabolic demands and/or greater growth efficiency than Eleuthera males. Our results call attention to sex-specific divergence in metabolism as a potential mechanism for intraspecific divergence in sexual size dimorphism.

Size is not everything: differing activity and foraging patterns between the sexes in a monomorphic mammal

Animals balance foraging with other activities, and activity patterns may differ between sexes due to differing physical requirements and reproductive investments. Sex-specific behavioural differences are common in sexually dimorphic mammals, but have received limited research attention in monomorphic mammals where the sexes are similar in body size. Eurasian beavers (Castor fiber) are obligate monogamous and monomorphic mammals and a good model species to study sex-specific differences. As females increase energy expenditure during reproduction, we hypothesized differing seasonal activity budgets, circadian activity rhythms and foraging patterns between male and reproducing female beavers. To test this hypothesis, we equipped adult beavers with VHF transmitters (N=41; 16 female, 25 male) and observed them throughout their active period at night from spring to late summer. Occurrence of their main activities (foraging, travelling and being in lodge) and use of food items (trees/shrubs, aquatic vegetation and herbs/grasses) were modelled to investigate sex-specific seasonal activity budgets and circadian activity rhythms. The sexes did not differ in time spent foraging across the season or night, but during spring, females resided more in the lodge and travelled less. Males and females both foraged on aquatic vegetation during spring, but females used this food source also during late summer, whereas males mostly foraged on trees/shrubs throughout the year. We conclude that seasonal activity budgets and foraging differ subtly between the sexes, which may relate to different energy budgets associated with reproduction and nutritional requirements. Such subtle seasonal behavioural adaptions may be vital for survival and reproduction of monomorphic species.Significance statementActivity budgets and foraging patterns of animals are key to their survival and may differ between males and females with different body sizes and physical requirements. In monomorphic species, where males and females have similar body sizes, fewer differences are expected, but may still be pronounced during certain times of the year. We modelled sex-specific seasonal activity budgets and circadian activity rhythms and use of food items in a monomorphic mammal, the Eurasian beaver. By treating season and time of day as a continuous variable rather than modelling differences within distinct predefined periods, we identified subtle sex-specific seasonal trends in activity budgets and use of food items.

A Strepsipteran parasite extends the lifespan of workers in a social wasp

In social wasps, female lifespan depends on caste and colony tasks: workers usually live a few weeks while queens as long as 1 year. Polistes dominula paper wasps infected by the strepsipteran parasite Xenos vesparum avoid all colony tasks, cluster on vegetation where parasite dispersal and mating occur, hibernate and infect the next generation of wasp larvae. Here, we compared the survival rate of infected and uninfected wasp workers. Workers’ survival was significantly affected by parasite sex: two-third of workers parasitized by a X. vesparum female survived and overwintered like future queens did, while all workers infected by a X. vesparum male died during the summer, like uninfected workers that we used as controls. We measured a set of host and parasite traits possibly associated with the observed lifespan extension. Infected overwintering workers had larger fat bodies than infected workers that died in the summer, but they had similar body size and ovary development. Furthermore, we recorded a positive correlation between parasite and host body sizes. We hypothesize that the manipulation of worker’s longevity operated by X. vesparum enhances parasite’s fitness: if workers infected by a female overwinter, they can spread infective parasite larvae in the spring like parasitized gynes do, thus contributing to parasite transmission.

COMUNIDADES DE PARÁSITOS DE PATAGONOTOTHEN TESSELLATA (RICHARDSON, 1845) (PISCES: NOTOTHENIIDAE) DE CHILE AUSTRAL: ¿QUÉ TAN DETERMINANTE ES EL SEXO DEL HOSPEDERO?

El conocimiento de comunidades de parásitos es muy abundante en peces marinos; sin embargo, hay varias especies que tienen escasa información parasitológica, como es el caso de Patagonotothen tessellata (Richardson, 1845), que posee una amplia distribución y abundancia en la Patagonia. Este estudio tuvo como objetivos determinar la composición comunitaria de parásitos en P. tessellata, y determinar el efecto del sexo de los hospederos en la composición parasítica a través de los descriptores poblacionales y comunitarios de parásitos. En enero de 2018 se recolectaron 118 ejemplares de P. tessellata en dos localidades cercanas entre sí, Muelle Prat y Muelle Remota, Puerto Natales, Chile Austral. En los peces capturados se encontró un total de 13 especies de parásitos, principalmente del Phylum Nematoda y Acanthocephala, de los cuales el nemátodo Pseudodelphis sp. seguido por el acantocéfalo Hypoechinorhynchus magellanicus (Szidat, 1950) fueron los de mayor prevalencia (78,8% y 53,4%, respectivamente) y abundancia (7,18 ± 17,95 y 7,30 ± 15,21, respectivamente). Se determinó que hospederos machos y hembras tenían iguales tamaños corporales y la misma correlación positiva entre peso-longitud, además, no se observaron diferencias significativas en composición y carga parasitaria. Mientras que el género de los peces tampoco afectó la composición parasítica para P. tessellata, pues, no hubo diferencias significativas en la prevalencia ni en la abundancia promedio de las especies de parásitos entre hospederos machos y hembras. Estos resultados indican la semejanza en las comunidades de parásitos entre sexos de P. tessellata y dan a presumir de que las condiciones del hábitat o la dieta de este pez son similares entre machos y hembras. De este modo, ambos grupos estarían expuestos a la infección de las mismas especies parásitas y en similares condiciones ambientales.

Goats show higher behavioural flexibility than sheep in a spatial detour task.

The ability to adapt to changing environments is crucial for survival and has evolved based on socio-ecological factors. Goats and sheep are closely related, with similar social structures, body sizes and domestication levels, but different feeding ecologies, i.e. goats are browsers and sheep are grazers. We investigated whether goats' reliance on more patchily distributed food sources predicted an increased behavioural flexibility compared to sheep. We tested 21 goats and 28 sheep in a spatial A-not-B detour task. Subjects had to navigate around a straight barrier through a gap at its edge. After one, two, three or four of these initial A trials, the gap was moved to the opposite end and subjects performed four B trials. Behaviourally more flexible individuals should move through the new gap faster, while those less behaviourally flexible should show greater perseveration. While both species showed an accuracy reduction following the change of the gap position, goats recovered from this perseveration error from the second B trial onwards, whereas sheep did so only in the fourth B trial, indicating differences in behavioural flexibility between the species. This higher degree of flexibility in goats compared to sheep could be linked to differences in their foraging strategies.

Body size perception, knowledge about obesity and factors associated with lifestyle change among patients, health care professionals and public health experts

BackgroundThe attitudes towards obesity may have an important role on healthier behavior. The goal of the present study was to explore the attitudes towards obesity and to investigate how these attitudes were associated with lifestyle-changing behavior among the patients attending primary care centers, health care professionals and public health experts.MethodsThis cross-sectional survey study was performed in 10 primary care offices in different regions in Lithuania and in 2 public health institutions. Nine hundred thirty-four patients, 97 nurses, 65 physicians and 30 public health experts have filled the questionnaire about attitudes towards obesity and presented data about lifestyle-changing activities during last 12 months. The attitudes were compared between different respondent groups and factors associated with healthier behaviors were analyzed among overweight/obese individuals in our study population.ResultsParticipants failed to visually recognize correct figure corresponding to male and female with obesity. Majority of respondents’ perceived obesity as a risk factor for heart diseases and diabetes but had less knowledge about other diseases associated with weight. About one third of respondents changed their lifestyle during last 12 months. Overweight individuals with age < 45 years (OR 1.64, 1.06–2.55; p = 0.025) were more likely and those who overestimated current weight (OR 0.44, 0.20–0.96; p = 0.036) less likely to change their lifestyle. Disappointment with their current weight (OR 2.57, 1.36–4.84; p = 0.003) was associated with healthier behavior among participants with obesity.ConclusionParticipants had similar body size perception and knowledge about obesity. Younger age had significant association with lifestyle changing behavior among overweight individuals and disappointment with current weight among obese participants.