ISSN / EISSN : 1570-7555 / 1570-7563
Published by: Brill Academic Publishers (10.1163)
Total articles ≅ 605
Latest articles in this journal
Animal Biology, Volume 71, pp 423-426; https://doi.org/10.1163/15707563-217104ci
Animal Biology, Volume 71, pp 375-388; https://doi.org/10.1163/15707563-bja10060
We tracked thirteen giant otters from three different groups in the Balbina Hydroelectric Reservoir. One of them was a transient animal, while the others were living in groups of five and seven individuals. Travelling was the most frequent behaviour, both for the transient otter (>40%) and group otters (46%). Diurnal resting was the longest-lasting behaviour. Most giant otter behaviour in the reservoir showed little difference when compared with the behaviour of giant otters living in nondammed areas, indicating a significant degree of resilience of this species. However, otters in the reservoir spent more time travelling, probably because their territory sizes were much greater than the territories of giant otters in nondammed areas. The frequency of fishing was similar to what has been recorded elsewhere, suggesting that current fish density and availability in the reservoir is similar to what is observed in nondammed areas. Nevertheless, otters in Balbina spent more time fishing than those in nondammed areas, which alternatively could suggest that fish density in the reservoir was low and could be compensated by increasing the time spent fishing. The high frequency of intraspecific kleptoparasitism observed in this study (62%) is noteworthy, although virtually undocumented for this species. This is the first study of giant otter behaviour in a hydroelectric reservoir that can be used for the conservation of this endangered species in man-made lakes.
Animal Biology, Volume 71, pp 407-421; https://doi.org/10.1163/15707563-bja10062
The set-point hypothesis states that there is a biological control method in mammals that actively regulates weight toward a predetermined set weight for each individual, which may occur by regulation of energy intake or energy expenditure. In order to investigate the effects of low temperature on body mass regulation in Eothenomys olitor, body mass, body fat mass, food intake, resting metabolic rate (RMR), non-shivering thermogenesis (NST), serum leptin levels, morphology, biochemical indexes of liver and brown adipose tissue (BAT) and hypothalamic neuropeptide genes expression were measured during cold acclimatization. The results showed that there was no significant difference in body mass, but food intake, RMR and NST increased during cold acclimatization. Cytochrome c oxidase (COX) and α-glycerophosphate oxidase (α-GPO) activities in liver and BAT were significantly enhanced during cold acclimatization, and triiodothyronine (T3) and thyroxine (T4) levels in serum were significantly higher than those in the control group. Serum leptin levels decreased after cold acclimatization. Low temperature significantly increased the expression of neuropeptide Y (NPY) and agouti-related peptide (AgRP), while it decreased cocaine- and amphetamine-regulated transcript peptide (CART) and pro-opiomelanocortin (POMC) expressions. All of the above results suggested that body mass in E. olitor can remain relatively stable at low temperature, which conforms to the ‘set-point hypothesis’. However, the species showed differences with sympatric species, such as E. miletus, Apodemus chevrieri and Tupaia belangeri. Moreover, E. olitor can cope with low temperature by increasing its metabolic rate and thermogenesis properties.
Animal Biology, Volume 71, pp 389-405; https://doi.org/10.1163/15707563-bja10061
The results of a craniometric analysis of the bank vole (Myodes glareolus) were evaluated in this study. Twenty cranial variables were measured and evaluated on 149 skulls (78 males, 71 females) with respect to sex and age. The main aim of this study was to test the sexual dimorphism in skull size. Overall, our results showed that on average, the values for adult and subadult females of M. glareolus were higher than for males. Results presented here thus reveal sexual differences in the measured cranial traits, most expressed for the length of the mandible and the height of the mandible. The effect size was very large for the length of the first upper molar. Comparison of our results with those from other countries confirmed that there are regional differences. These findings highlight the need for craniometric analysis of species also at the regional level.
Animal Biology, Volume 71, pp 349-360; https://doi.org/10.1163/15707563-bja10057
Paradactylodon persicus gorganensis is a critically endangered salamander found in northeastern Iran which faces increasing major anthropogenic threats such as agriculture, industry and mining. The aim of the current study is to identify key environmental variables associated with the species’ presence. Also, measuring and comparing the water quality parameters in habitats where P. p. gorganensis is present and absent are the other aims of the study. The results indicate that high pH and dissolved oxygen values have a negative effect on the species’ presence, while its presence was strongly correlated with low mean water temperatures. The species’ range in response to the climate change will shift to the south and east, where areas of high elevation occur, because the species favors cold habitats. This study indicates that it will be particularly important to evaluate the whole range where P. p. gorganensis exists when preparing conservation action plans. It is recommended that ex-situ conservation programs are incorporated into conservation planning for the species, because the number of individuals in the wild is so low and their future viability is fragile.
Animal Biology, Volume 71, pp 361-373; https://doi.org/10.1163/15707563-bja10059
Domestic geese can reduce the amount of food intake when brooding. Because of the reduction in food intake, the total number of microorganisms in the gut is also reduced. Will this affect the goose’s thinking and make the goose stop brooding and eat food? We hypothesize that gut microbiota affects the brain through a brain–gut peptide and further regulates the breeding behavior of geese. In this study, we evaluated the microbiome related to the goose and transcription groups of brooding and egg production periods. The changes and differences in gut microbiota and gene expression of female geese in different reproduction periods were analyzed, and the possible interaction between them was explored. The results showed that the relative abundance of Faecalibacterium with a growth-promoting effect in the cecum was higher in the egg production group than in the brooding group. Microbial metabolic pathways with significant differences between the two groups were also enriched in the secondary functional groups with different gut microbiota metabolism. The downregulated genes in the egg production group were mainly related to energy metabolism, such as ATP synthesis-related genes. These results suggest that the brooding group’s gut microbiota can make relevant changes according to the reproduction stage of the goose. Since the amount of food taken in is reduced, it can promote the decomposition of the host’s fat. Simultaneously, insulin is also used to deliver messages to the brain; it is necessary to end the brooding behavior at an appropriate time and for eating to start.
Animal Biology, Volume 71, pp 329-347; https://doi.org/10.1163/15707563-bja10058
Organisms face numerous environmental stressors, which can affect developmental precision, including symmetry of various physical characteristics. Fluctuating asymmetry (FA) has therefore been suggested as a simple and efficient tool for assessing sub-lethal stress levels. We analyzed FA in two sympatric lizard species (Iberolacerta horvathi and Podarcis muralis) to determine potential effects of interspecific competition and urbanization, as proxies of stress, taking into account sexual dimorphism and environmental conditions. We sampled 16 syntopic and allotopic populations and used geometric morphometrics of head morphology. We detected significant but mixed effects on the head asymmetry from the environment and the syntopic occurrence that differed between species. P. muralis lizards had more asymmetric heads at higher altitudes, while I. horvathi lizards did at mid altitudes, which may be explained by P. muralis experiencing environmental stress of colder conditions at higher altitudes. The mid-altitude effect on asymmetries in I. horvathi might be explained by a lower availability of stony walls and higher abundance of P. muralis, thus higher competition. The asymmetry of supraciliary granules was affected by the presence of other species. However, lizards from allotopic populations attained larger asymmetries compared to lizards from syntopic populations, which was the opposite from what was expected. There was no effect of urbanization in P. muralis, which could be due to relatively low pollution and habitat degradation in study locations. Overall, we highlighted the possibility of using lizards and FA for bioindication of environmental stressors and especially improved the knowledge gap in the research of biotic stressors.
Animal Biology, Volume 71, pp 279-296; https://doi.org/10.1163/15707563-bja10055
Elevation and anthropopression are important factors affecting terrestrial water bear dynamics. In the present study, we characterize the taxonomic composition, diversity, and community structure of tardigrades along an elevational gradient with different anthropopression in Alturas de Boniato, Santiago de Cuba. Samples were collected in four sampling sites and all tardigrades were extracted. Alpha diversity indices were calculated. Hierarchical community organization was determined and variation among sampling sites was calculated using the Jaccard index for beta diversity. Some variables that influenced composition and taxon diversity were also evaluated. A total of 413 tardigrades belonging to seven taxa and five eggs were found. The most abundant taxa were Paramacrobiotus sp., Macrobiotus sp. and Milnesium sp. 1. Differences between sampling sites were largely due to turnover, especially at the higher-elevation sites. Nesting characterized the lower-elevation sites. The variables that had the greatest influence on species composition were anthropopression and a mixture of various macro- and microenvironmental variables.
Animal Biology, Volume 71, pp 297-310; https://doi.org/10.1163/15707563-bja10053
Animals with complex life cycles, such as amphibians, shift their habitats when they metamorphose. Metamorphosing traits (e.g., size at, and timing of, metamorphosis) at an early stage can affect the growth, reproduction, and survival in the adult stage. Thus, metamorphosing traits are important factors that affect the fitness of the individuals. Although size at metamorphosis in the field has been investigated in amphibians, its relationship with environmental factors has been scarce. We aimed to quantify variations in the mass at metamorphosis of a stream frog, Odorrana splendida, among multiple streams, and show the relationship of these variations with environmental conditions. We searched for metamorphs in 11 field streams and measured their body size. We then examined the relationship between environmental conditions of each stream and the mass at metamorphosis to reveal the factors determining the mass. We found 229 metamorphs over three years. The estimated mass at metamorphosis ranged from 0.17 g to 1.44 g, with a coefficient of variation among streams of 0.38. The size at metamorphosis significantly differed among streams, and was found to be positively affected by water temperature and chlorophyll a concentration, and negatively affected by altitude, slope gradient, and the number of adult calls. We showed that O. splendida has a large variation in mass at metamorphosis within and among natural streams. A lower mass at metamorphosis may correlate with scarce food resources in the stream and higher competition during the larval stages, resulting from a higher number of mating adults.
Animal Biology, Volume 71, pp 261-278; https://doi.org/10.1163/15707563-bja10054
Social group is associated with life-history traits and can predict brain size variation in cooperative primates and some other mammal groups, but such explicit relationships remain enigmatic in cooperatively breeding birds. Indeed, some compositions of social group in cooperative species (e.g., helper number and group size) would affect the fitness of breeders by providing alloparental care. Here, we conducted comparative tests of the relationship between the social group and both life-history traits and brain size across 197 species of cooperatively breeding birds using phylogenetically controlled comparative analyses. We did not find any correlations between helper numbers and both life-history traits and brain size. However, we found that maximum group size was positively associated with clutch size. Moreover, average group size has positive associations with body mass and relative brain size. Our findings suggest that helper numbers cannot promote variation in relative brain size, while larger groups may predict bigger brains in cooperatively breeding birds.