Changes in habitat characteristics are known to have profound effects on biotic communities and their functional traits. In the context of an urban-rural gradient, urbanisation drastically alters ...abiotic characteristics, e.g., by increasing environmental temperatures and through light pollution. These abiotic changes significantly impact the functional traits of organisms, particularly insects. Furthermore, changes in habitat characteristics also drive changes in the behavioural traits of animals, allowing them to adapt and thrive in new environments. In our study, we focused on the synanthropic ant species Lasius niger as a model organism. We conducted nocturnal field observations and complemented them with laboratory experiments to investigate the influence of night warming (NW) associated with Urban Heat Islands (UHI), light pollution (ALAN), and habitat type on ant foraging behaviour. In addition, we investigated the influence of elevated temperatures on brood development and worker mortality. Our findings revealed that urban populations of L. niger were generally more active during the night compared to their rural counterparts, although the magnitude of this difference varied with specific city characteristics. In laboratory settings, higher temperatures and continuous illumination were associated with increased activity level in ants, again differing between urban and rural populations. Rural ants exhibited more locomotion compared to their urban counterparts when maintained under identical conditions, which might enable them to forage more effectively in a potentially more challenging environment. High temperatures decreased the developmental time of brood from both habitat types and increased worker mortality, although rural colonies were more strongly affected. Overall, our study provides novel insights into the influence of urban environmental stressors on the foraging activity pattern and colony development of ants. Such stressors can be important for the establishment and spread of synanthropic ant species, including invasive ones, and the biotic homogenization of anthropogenic ecosystems.
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•Ant foraging activity was generally higher in urban areas.•In the smaller and cooler cities, ant activity was higher in rural areas.•Results of a laboratory study followed the same trend found in the field study.•Urban locomotory traits suggested adaptations to weaker competitive pressures.•In urban areas, brood developed faster but worker mortality increased.
The reliance on visual cues can vary among ant species living in different habitats, and is mostly influenced by the level of ambient illumination and the morphological adaptations of ant species ...that can determine their period of daily activity. Thus, different illumination regimes might affect ant community composition in habitats with different ambient illumination intensities. Despite this, in the literature, information is scarce about the effects of ambient illumination on ant activity. In the present study, we investigated the effect of ambient illumination intensity on the activity of ant species and their community composition under herbaceous and woody plants in 24 localities from Kyiv and Kyiv region, Ukraine. Our results showed that the ambient illumination properties of the habitat type affect the presence of ant species and the activity of their workers. In open habitats, the maximum ambient illumination had a negative effect, whereas in closed, woody habitats the maximum ambient illumination and tree circumference generally had a positive effect on the number of non-dendrobiotic ant individuals found on individual plants. The dendrobiotic species were less affected by the maximum illumination intensity. Although, in closed habitats, the effect of the previous variables and their interaction had species-specific aspects. Based on the former, we can tell that more structured forest habitats can provide broader illumination intensity ranges, allowing more ant species to coexist. However, similar illumination intensity ranges can lead to overlaps in the activity of ant species under the same illumination conditions, especially in open habitats. The outcomes of these interactions are highly influenced by larger trees that besides lowering illumination intensities, can enhance ant worker activity and promote species coexistence.
The colony performance of social insects is supported by an efficient allocation of tasks among workers in the colony. The division of labor among ant workers is linked to age and caste polyethism, ...however, only a few studies have shown the relationship between workers’ behavioral variation and task performance. In this study, we investigated the task syndrome by testing the relationship between behavioral traits with task performance and
location switching
(switching the performance of tasks from inside to outside the nest) in the same-age workers of
Camponotus vagus
ants. We also investigated the division of labor in workers with and without
location switching
by checking if each caste is characterized by specific behavioral traits or tasks. Moreover, we checked whether the difference in the worker’s body size and its lifespan can influence task performance. Our results support the existence of task syndrome in ant workers by showing how individuals with specific behavioral traits are more likely to perform specific tasks within the colony. Moreover, the time of
location switching
was correlated with the tasks performed by the workers (
brood care
,
selfgrooming
and
walking
) and their behavioral traits (
aggressiveness
and
total distance
). In addition, worker size and lifespan are shown to influence task performance by the workers. Altogether, our study underpins the relationship between the behavioral traits and the task allocation and performance of workers within an ant colony.
Arthropods play an essential role in steppe ecosystems. However, studies testing the overall response of terrestrial arthropods to overgrazing are scarce. The problem is particularly worrisome in ...Central Asia, while, to date, only a very few broader studies have been conducted in this region. We investigated how epigeic terrestrial arthropod assemblages respond to different livestock grazing pressure in two ecozones in SE Mongolia by examining their structure using pitfall traps. We also assessed which groups can be utilised as the most efficient indicators of grazing intensity. Our analyses demonstrated that the habitat type, grazing intensity, and the interaction of these variables had a significant effect on the overall species composition and abundance. However, the grazing intensity caused different changes in the composition of arthropod communities in both studied ecozones. Contrary to the semi-desert, in the steppe habitat, the grazing had the strongest impact in the moderately grazed site. It is most likely because steppe-dwelling species are more sensitive to loss of plant biomass and changes in habitat structure. We also found that the most representative species within and from different groups can react differently to changing grazing intensities, indicating with their presence the characteristics of the respective habitat. Such differences should also be considered when elaborating the management plan of conserved species but also when applying grazing management in different habitat types. Our survey is one of the most comprehensive in Central Asia and should help implement further, more targeted studies in the corresponding habitats.
In meadow steppes and other arid habitats, livestock grazing is one of the most severe causes of desertification and leads to an overall decline in vegetation cover, plant species richness and aboveground biomass, and, consequently, most often negatively affects arthropod diversity.
Although the impact of grazing on arthropod diversity has already been the subject of numerous studies, most of them were focused only on a single or small number of arthropods and were conducted outside Central Asia (e.g., there is only one paper dealing with analyses of several arthropod groups conducted in Mongolia, where over 40% of the human population depends on pastoral livestock production and up to 90% of its territory belongs to various arid areas).
We hypothesise that the overall diversity of different arthropod groups will change according to the grazing intensities, and these changes will depend on the habitat type and will differ between arthropod groups.
Our analyses demonstrated that the habitat type, grazing intensity, and the interaction of these two variables significantly impacted the overall species composition and abundance.
Our results highlight that the different terrestrial arthropod groups and representative species of the most abundant groups can react differently to changes in grazing intensity, and such differences should be considered when elaborating the management plan of conserved species and when applying grazing management in different habitat types.
Our results also highlight that the species diversity alone cannot indicate the changes in species composition along the grazing intensity, and one should also consider the individual needs of specific species while investigating the impact of grazing on arid habitats.
The hierarchical organization of multi-species ant communities can be determined by the colony size and worker density-dependent differences in behaviour, recruitment efficiency, and aggressiveness ...between colonies of different species. In this study, we compared the competitive effects of two territorial wood ant species, Formica rufa and F. polyctena, on the ant species subordinated to them (encounterers and submissives) that nest close-by their mounds. The nests of subordinates were mapped in 10 m2 plots around the mounds of each of the two wood ant species, situated at a distance of 10, 20 and 30 m in four directions. The most abundant subordinate species were two Myrmica species: M. rubra and M. ruginodis. Interestingly, the nests of subordinates had an even diversity, density and distribution along with the distance from the wood ant mounds. The wood ant presence had a species-specific negative effect on some of the subordinate species, which can be in relation with the smaller mound sizes in F. rufa compared to F. polyctena. Based on our results it seems that subordinate species, due to their adaptability, might tolerate the circumstances close-by the wood ant mounds by changes in their strategies, foraging behaviour, and switching to the use of alternative food sources, like corpses of wood ants present in high abundance. Although these might not allow reaching normal colony size and reproduction, they may allow the colonies to survive while maintaining relatively large nest densities.
•Competitive effects of two territorial wood ants, Formica rufa and F. polyctena, were studied.•Nests of subordinate ants had an even diversity, density and distribution close-by the mounds.•Species-specific negative effects can be related to mound size differences among the two wood ants.•Subordinate species might tolerate the circumstances close-by the mounds due to their adaptability.•Adaptations may allow the subordinates to survive while maintaining relatively large nest densities.
This study examined the emergence and characteristics of bilateral asymmetry of the upper limb during development in a medieval agricultural population from Hungary, and investigated the agricultural ...activity-types in a bioarchaeological and biomechanical context. The skeletal remains of 169 nonadult individuals were selected from the cemetery of Bátmonostor-Pusztafalu, providing 134 cases for humeral diameter and length, 70 cases for radial length and 62 cases for ulnar length measurements. Biological age was estimated by using tooth eruption. Age groups were defined on the basis of the development of motor skills in children. Statistical analyses included correlation, Chi-square test, Fisher analysis and ANOVA. Our investigation revealed that the frequency of asymmetry increased significantly during growth with a shift to the right side in all measurements and reached adult-like distribution in early childhood. The bilateral asymmetry increased with age in humeral length, while other measurements revealed no change. The magnitude of asymmetry decreased with age in humeral diameter, but remained constant in other measurements. Our observations strengthen the hypothesis that right-sided asymmetry develops gradually during growth. Our findings also illustrate the effects of medieval agricultural labour on upper limb asymmetry: mechanical loading has various effects during development both on the magnitude and on direction of asymmetry.
The understanding of brain computations requires methods that read out neural activity on different spatial and temporal scales. Following signal propagation and integration across a neuron and ...recording the concerted activity of hundreds of neurons pose distinct challenges, and the design of imaging systems has been mostly focused on tackling one of the two operations. We developed a high-resolution, acousto-optic two-photon microscope with continuous three-dimensional (3D) trajectory and random-access scanning modes that reaches near-cubic-millimeter scan range and can be adapted to imaging different spatial scales. We performed 3D calcium imaging of action potential backpropagation and dendritic spike forward propagation at sub-millisecond temporal resolution in mouse brain slices. We also performed volumetric random-access scanning calcium imaging of spontaneous and visual stimulation-evoked activity in hundreds of neurons of the mouse visual cortex in vivo. These experiments demonstrate the subcellular and network-scale imaging capabilities of our system.
Background
Unraveling the mechanisms of pain in chronic pancreatitis (CP) remains a true challenge. The rapid development of pancreatic surgery in the twentieth century, usage of advanced molecular ...biological techniques, and emergence of clinician-scientists have enabled the elucidation of several mechanisms that lead to the chronic, complicated neuropathic pain syndrome in CP. However, the proper analysis of pain in CP should include three main arms of mechanisms: “peripheral nociception,” “peripheral/pancreatic neuropathy and neuroplasticity,” and “central neuropathy and neuroplasticity.”
Discussion
According to our current knowledge, pain in CP involves sustained sensitization of pancreatic peripheral nociceptors by neurotransmitters and neurotrophic factors following neural damage. This peripheral pancreatic neuropathy leads to intrapancreatic neuroplastic alterations that involve a profound switch in the autonomic innervation of the human pancreas via “neural remodeling.” Furthermore, this neuropathy entails a hyperexcitability of spinal sensory second-order neurons, which are subject to modulation from the brainstem via descending facilitation. Finally, viscerosensory cortical areas react to this central sensitization via spatial reorganization and thus a central neuroplasticity. The present review summarizes the current findings in these arms of mechanisms and introduces a novel concept to consistently describe pain in CP as a “predominantly neuropathic,” “mixed-type” pain.
Dolines are small- to large-sized bowl-shaped depressions of karst surfaces. They may constitute important microrefugia, as thermal inversion often maintains cooler conditions within them. This study ...aimed to identify the effects of large- (macroclimate) and small-scale (slope aspect and vegetation type) environmental factors on cool-adapted plants in karst dolines of East-Central Europe. We also evaluated the potential of these dolines to be microrefugia that mitigate the effects of climate change on cool-adapted plants in both forest and grassland ecosystems.
We compared surveys of plant species composition that were made between 2007 and 2015 in 21 dolines distributed across four mountain ranges (sites) in Hungary and Romania. We examined the effects of environmental factors on the distribution and number of cool-adapted plants on three scales: (1) regional (all sites); (2) within sites and; (3) within dolines. Generalized linear models and non-parametric tests were used for the analyses.
Macroclimate, vegetation type and aspect were all significant predictors of the diversity of cool-adapted plants. More cool-adapted plants were recorded in the coolest site, with only few found in the warmest site. At the warmest site, the distribution of cool-adapted plants was restricted to the deepest parts of dolines. Within sites of intermediate temperature and humidity, the effect of vegetation type and aspect on the diversity of cool-adapted plants was often significant, with more taxa being found in grasslands (versus forests) and on north-facing slopes (versus south-facing slopes).
There is large variation in the number and spatial distribution of cool-adapted plants in karst dolines, which is related to large- and small-scale environmental factors. Both macro- and microrefugia are therefore likely to play important roles in facilitating the persistence of cool-adapted plants under global warming.
Electronic neuromuscular monitoring is not widely used to determine either the reversal requirements for neuromuscular block before extubation of the trachea, or to determine if there is any ...subsequent postoperative residual neuromuscular block (PORNB).
To investigate the incidence of PORNB using acceleromyography after spontaneous recovery of rocuronium-induced block and to compare this with the administration of sugammadex, neostigmine or a placebo.
Partially randomised, partially randomised, placebo-controlled, double-blind, four-group parallel-arm study.
Single-centre study performed between October 2013 and December 2015 in a university hospital.
Of the 134 eligible patients, 128 gave their consent and 125 of these completed the study.
Patients received general anaesthesia with propofol, sevoflurane, fentanyl and rocuronium. Neuromuscular transmission was measured by acceleromyography (TOF-Watch-SX; Organon Teknika B.V., Boxtel, the Netherlands) but the anaesthetist was blind to the results. If the anaesthetist deemed pharmacological reversal to be necessary before extubation of the trachea then patients were assigned randomly to receive either sugammadex (2.0 mg kg), neostigmine (0.05 mg kg) or a placebo. In the postanaesthesia care unit, an independent anaesthetist, unaware of the treatment given, assessed the neuromuscular function using acceleromyography.
The incidence of a normalised train-of-four ratio less than 0.9 on arrival in the recovery room.
In total, 125 patients were recruited. Neuromuscular block was allowed to recover spontaneously in 50 patients, whereas the remainder received either sugammadex (27), neostigmine (26) or placebo (22). The number of cases with PORNB were one (3.7%), four (15%), 13 (26%) and 10 (45%) after sugammadex, neostigmine, spontaneous recovery and placebo, respectively. Sugammadex and neostigmine were more effective than placebo odds ratio (OR): 0.05, 95% confidence interval (CI): 0.005 to 0.403, P = 0.005; OR: 0.22, 95% CI: 0.056 to 0.85, P = 0.028, respectively. Sugammadex performed better than spontaneous recovery (OR: 0.11, 95% CI: 0.014 to 0.89, P = 0.039) unlike neostigmine (OR: 0.52, 95% CI: 0.15 to 1.79, P = 0.297). Yet, antagonism (pooled data) was more effective than spontaneous recovery (OR: 0.3, 95% CI: 0.1 to 0.9, P = 0.03).
Although pharmacological reversal based on clinical signs was superior to spontaneous recovery it did not prevent PORNB, irrespective of the reversal agent.
The study is registered under EUDRACT number 2013-001965-17.
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