Subsidy Quality Affects Common Riparian Web-Building Spiders: Consequences of Aquatic Contamination and Food Resource

Anthropogenic stressors can affect the emergence of aquatic insects. These insects link aquatic and adjacent terrestrial food webs, serving as high-quality subsidy to terrestrial consumers, such as spiders. While previous studies have demonstrated that changes in the emergence biomass and timing may propagate across ecosystem boundaries, the physiological consequences of altered subsidy quality for spiders are largely unknown. We used a model food chain to study the potential effects of subsidy quality: Tetragnatha spp. were exclusively fed with emergent Chironomus riparius cultured in the absence or presence of either copper (Cu), Bacillus thuringiensis var. israelensis (Bti), or a mixture of synthetic pesticides paired with two basal resources (Spirulina vs. TetraMin (R)) of differing quality in terms of fatty acid (FA) composition. Basal resources shaped the FA profile of chironomids, whereas their effect on the FA profile of spiders decreased, presumably due to the capacity of both chironomids and spiders to modify (dietary) FA. In contrast, aquatic contaminants had negligible effects on prey FA profiles but reduced the content of physiologically important polyunsaturated FAs, such as 20:4n-6 (arachidonic acid) and 20:5n-3 (eicosapentaenoic acid), in spiders by approximately 30% in Cu and Bti treatments. This may have contributed to the statistically significant decline (40%-50%) in spider growth. The observed effects in spiders are likely related to prey nutritional quality because biomass consumption by spiders was, because of our experimental design, constant. Analyses of additional parameters that describe the nutritional quality for consumers such as proteins, carbohydrates, and the retention of contaminants may shed further light on the underlying mechanisms. Our results highlight that aquatic contaminants can affect the physiology of riparian spiders, likely by altering subsidy quality, with potential implications for terrestrial food webs. (c) 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC

Cheetah marking sites are also used by other species for communication : evidence from photographic data in a comparative setup

Many mammalian species communicate via olfactory communication placed at particular locations. The majority of these studies focused on intraspecific communication. More recently, studies have also investigated interspecific communication and recorded prey animals sniffing olfactory cues left by predators and predators investigating or counter-marking cues left by other predator species. The purpose of exchanging olfactory cues within a species community is little understood. Using a comparative study design, we investigated the behaviour of a mammalian community at cheetah marking trees and paired control trees using camera traps on Namibian farmland. We tested the predictions derived from hypotheses regarding the reasons for visits to the marking trees. Cheetah marking trees and control trees were visited 1101 times by 29 mammalian species (excluding cheetahs), with more species recorded at the marking trees than control trees. Two competitively subordinate carnivore species made more visiting and sniffing events, respectively, at cheetah marking trees than control trees, possibly to assess the time since cheetahs were in the area. Two opportunistic scavenger species sniffed more frequently at the marking trees than control trees, perhaps to feed on undigested prey remains in scats. One common prey species of cheetahs had fewer visiting events at the marking trees than control trees, likely to reduce encounters with cheetahs. Further, one species that is rarely preyed by cheetahs marked cheetah marking trees at the same frequency as control trees, suggesting it uses conspicuous sites rather for intraspecific than interspecific communication. Thus, trees used by cheetahs for marking also play an important role in olfactory communication for a variety of mammalian species.Open Access funding enabled and organized by Projekt DEAL. The publication of this article was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – project number 491292795. This study was funded by the Messerli Foundation in Switzerland. Sarah Edwards received a post-doctoral bursary from the University of Pretoria, South Africa.https://link.springer.com/journal/42991hj2023Centre for Wildlife Managemen

Environmentally relevant fungicide levels modify fungal community composition and interactions but not functioning

Aquatic hyphomycetes (AHs), a group of saprotrophic fungi adapted to submerged leaf litter, play key functional roles in stream ecosystems as decomposers and food source for higher trophic levels. Fungicides, controlling fungal pathogens, target evolutionary conserved molecular processes in fungi and contaminate streams via their use in agricultural and urban landscapes. Thus fungicides pose a risk to AHs and the functions they provide. To investigate the impacts of fungicide exposure on the composition and functioning of AH communities, we exposed four AH species in monocultures and mixed cultures to increasing fungicide concentrations (0, 5, 50, 500, and 2500 mg/L). We assessed the biomass of each species via quantitative real-time PCR. Moreover, leaf decomposition was investigated. In monocultures, none of the species was affected at environmentally relevant fungicide levels (5 and 50 mg/L). The two most tolerant species were able to colonize and decompose leaves even at very high fungicide levels (>= 500 mg/L), although less efficiently. In mixed cultures, changes in leaf decomposition reflected the response pattern of the species most tolerant in monocultures. Accordingly, the decomposition process may be safeguarded by tolerant species in combination with functional redundancy. In all fungicide treatments, however, sensitive species were displaced and interactions between fungi changed from complementarity to competition. As AH community composition determines leaves' nutritional quality for consumers, the data suggest that fungicide exposures rather induce bottom-up effects in food webs than impairments in leaf decomposition. (C) 2021 The Author(s). Published by Elsevier Ltd

Communication hubs of an asocial cat are the source of a human - carnivore conflict and key to its solution

Human%wildlife conflicts occur worldwide. Although many nonlethal mitigation solutions are available, they rarely use the behavioral ecology of the conflict species to derive effective and long-lasting solutions. Here, we use a long-term study with 106 GPS-collared free-ranging cheetahs (Acinonyx jubatus) to demonstrate how new insights into the socio-spatial organization of this species provide the key for such a solution. GPS-collared territory holders marked and defended communication hubs (CHs) in the core area of their territories. The CHs/territories were distributed in a regular pattern across the landscape such that they were not contiguous with each other but separated by a surrounding matrix. They were kept in this way by successive territory holders, thus maintaining this overdispersed distribution. The CHs were also visited by nonterritorial cheetah males and females for information exchange, thus forming hotspots of cheetah activity and presence. We hypothesized that the CHs pose an increased predation risk to young calves for cattle farmers in Namibia. In an experimental approach, farmers shifted cattle herds away from the CHs during the calving season. This drastically reduced their calf losses by cheetahs because cheetahs did not follow the herds but instead preyed on naturally occurring local wildlife prey in the CHs. This implies that in the cheetah system, there are %problem areas,% the CHs, rather than %problem individuals.% The incorporation of the behavioral ecology of conflict species opens promising areas to search for solutions in other conflict species with nonhomogenous space use

Concepts in mature T-cell lymphomas - highlights from an international joint symposium on T-cell immunology and oncology

Growing attention in mature T-cell lymphomas/leukemias (MTCL) is committed to more accurate and meaningful classifications, improved pathogenetic concepts and expanded therapeutic options. This requires considerations of the immunologic concepts of T-cell homeostasis and the specifics of T-cell receptor (TCR) affinities and signaling. Scientists from various disciplines established the CONTROL-T research unit and in an international conference on MTCL they brought together experts from T-cell immunity, oncology, immunotherapy and systems biology. We report here meeting highlights on the covered topics of diagnostic pitfalls, implications by the new WHO classification, insights from discovered genomic lesions as well as TCR-centric concepts of cellular dynamics in host defense, auto-immunity and tumorigenic clonal escape, including predictions to be derived from in vivo imaging and mathematical modeling. Presentations on novel treatment approaches were supplemented by strategies of optimizing T-cell immunotherapies. Work packages, that in joint efforts would advance the field of MTCL more efficiently, are identified

Siponimod (BAF-312) Attenuates Perihemorrhagic Edema And Improves Survival in Experimental Intracerebral Hemorrhage

Background and Purpose- Perihemorrhagic edema (PHE) is associated with poor outcome after intracerebral hemorrhage (ICH). Infiltration of immune cells is considered a major contributor of PHE. Recent studies suggest that immunomodulation via S1PR (sphingosine-1-phosphate receptor) modulators improve outcome in ICH. Siponimod, a selective modulator of sphingosine 1-phosphate receptors type 1 and type 5, demonstrated an excellent safety profile in a large study of patients with multiple sclerosis. Here, we investigated the impact of siponimod treatment on perihemorrhagic edema, neurological deficits, and survival in a mouse model of ICH. Methods- ICH was induced by intracranial injection of 0.075 U of bacterial collagenase in 123 mice. Mice were randomly assigned to different treatment groups: vehicle, siponimod given as a single dosage 30 minutes after the operation or given 3x for 3 consecutive days starting 30 minutes after operation. The primary outcome of our study was evolution of PHE measured by magnetic resonance-imaging on T2-maps 72 hours after ICH, secondary outcomes included evolution of PHE 24 hours after ICH, survival and neurological deficits, as well as effects on circulating blood cells and body weight. Results- Siponimod significantly reduced PHE measured by magnetic resonance imaging (P=0.021) as well as wet-dry method (P=0.04) 72 hours after ICH. Evaluation of PHE 24 hours after ICH showed a tendency toward attenuated brain edema in the low-dosage group (P=0.08). Multiple treatments with siponimod significantly improved neurological deficits measured by Garcia Score (P=0.03). Survival at day 10 was improved in mice treated with multiple dosages of siponimod (P=0.037). Mice treated with siponimod showed a reduced weight loss after ICH (P=0.036). Conclusions- Siponimod (BAF-312) attenuated PHE after ICH, increased survival, and reduced ICH-induced sensorimotor deficits in our experimental ICH-model. Findings encourage further investigation of inflammatory modulators as well as the translation of BAF-312 to a human study of ICH patients