scholarly journals Behavioural responses to con- and heterospecific alarm cues by an alien and a coexisting native fish

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Piotr Kłosiński ◽  
Jarosław Kobak ◽  
Mateusz Augustyniak ◽  
Roman Pawlak ◽  
Łukasz Jermacz ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Invasion Success ◽  
Ecological Niches ◽  
Skin Extract ◽  
Phylogenetic Distance ◽  
Alarm Cues ◽  
Sympatric Populations ◽  
Social Distancing ◽  
Interspecific Differences ◽  
Reduced Mobility

AbstractThe monkey goby Neogobius fluviatilis is an invasive Ponto-Caspian fish that enters habitats of the native gudgeon Gobio gobio in European freshwaters, likely belonging to the same prey guild. Their abilities to detect and avoid predation have been poorly understood, although these traits may contribute to the competitive advantage and drive the invasion success of the goby. We tested intra- and interspecific responses of fish from sympatric populations to damage-released alarm cues (skin extract) in laboratory. Both species of fish responded to conspecific and heterospecific cues, but their responses to conspecifics were more diverse (changed social distancing among individuals, reduced vertical and horizontal movement) than those elicited by heterospecifics (changed social distancing only). Moreover, the fish differed in their anti-predation behaviour: the gudgeon increased whilst the monkey goby decreased inter-individual distances and only the gudgeon exhibited thigmotaxis and reduced mobility in response to the conspecific cues. Interspecific differences show that the species exhibit distant anti-predation strategies. This might be associated with their phylogenetic distance and/or higher differentiation of their ecological niches than commonly assumed. Besides, our results suggest that alien species be included in the interspecific exchange of information in local fish assemblages.

Does habitat complexity influence the ability of fathead minnows to learn heterospecific chemical alarm cues?

2003 ◽  
Vol 81 (5) ◽  
pp. 923-927 ◽  
Author(s):  
M S Pollock ◽  
D P Chivers
Keyword(s):  
Habitat Complexity ◽  
Complex Structure ◽  
Pimephales Promelas ◽  
Ecological Factors ◽  
Habitat Characteristics ◽  
Predatory Fish ◽  
Skin Extract ◽  
Alarm Cues ◽  
Fathead Minnows ◽  
Chemical Alarm Cues

Numerous aquatic animals release chemical cues when attacked by a predator. These cues "warn" other individuals of danger and have been termed alarm cues. Cross-species responses to alarm cues are common and in some cases result from learned recognition. However, little is known about the ecological factors that could influence this learned recognition. The current study focuses on the role of habitat complexity in the learning of heterospecific alarm cues. We introduced brook stickleback (Culaea inconstans) into outdoor pools containing fathead minnows (Pimephales promelas) naïve to stickleback. The pools all contained a predatory fish (northern pike, Esox lucius) but varied in habitat characteristics. Pools representing high-complexity habitats had a large amount of structure to obscure the visual environment, while pools representing low-complexity habitats had minimal structure. After 8 days, fish were removed from the pools and behavioural assays were conducted in the laboratory. We tested the minnows for a response to either stickleback skin extract (experimental) or swordtail (Xiphophorus helleri) skin extract (control) and found that minnows conditioned in pools with little structure had learned to recognize stickleback alarm cues, while those from pools with complex structure did not recognize stickleback alarm cues.

scholarly journals How effective are social distancing policies? Evidence on the fight against COVID-19

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257363
Author(s):  
Ulrich Glogowsky ◽  
Emanuel Hansen ◽  
Simeon Schächtele
Keyword(s):  
Event Study ◽  
Rural Areas ◽  
Point Estimate ◽  
Social Distancing ◽  
Reduced Mobility

To fight the spread of COVID-19, many countries implemented social distancing policies. This is the first paper that examines the effects of the German social distancing policies on behavior and the epidemic’s spread. Exploiting the staggered timing of COVID-19 outbreaks in extended event-study models, we find that the policies heavily reduced mobility and contagion. In comparison to a no-social-distancing benchmark, within three weeks, the policies avoided 84% of the potential COVID-19 cases (point estimate: 499.3K) and 66% of the potential fatalities (5.4K). The policies’ relative effects were smaller for individuals above 60 and in rural areas.

scholarly journals Towards unravelling Wolbachia global exchange: a contribution from the Bicyclus and Mylothris butterflies in the Afrotropics

2020 ◽  
Author(s):  
Anne Duplouy ◽  
Robin Pranter ◽  
Haydon Warren-Gash ◽  
Robert Tropek ◽  
Niklas Wahlberg
Keyword(s):  
Central Africa ◽  
Ecological Factors ◽  
Life Cycles ◽  
Ecological Niches ◽  
Phylogenetic Distance ◽  
Insect Communities ◽  
Arthropod Species ◽  
Global Pandemic ◽  
Forest Regions ◽  
Global Exchange

Abstract Background Phylogenetically closely related strains of maternally inherited endosymbiotic bacteria are often found in phylogenetically divergent, and geographically distant insect host species. The interspecies transfer of the symbiont Wolbachia has been thought to have occurred repeatedly, facilitating its observed global pandemic. Few ecological interactions have been proposed as potential routes for the horizontal transfer of Wolbachia within natural insect communities. These routes are however likely to act only at the local scale, but how they may support the global distribution of some Wolbachia strains remains unclear. Results Here, we characterize the Wolbachia diversity in butterflies from the tropical forest regions of central Africa to discuss transfer at both local and global scales. We show that numerous species from both the Mylothris (family Pieridae) and Bicyclus (family Nymphalidae) butterfly genera are infected with similar Wolbachia strains, despite only minor interclade contacts across the life cycles of the species within their partially overlapping ecological niches. The phylogenetic distance and differences in resource use between these genera rule out the role of ancestry, hybridization, and shared host-plants in the interspecies transfer of the symbiont. Furthermore, we could not identify any shared ecological factors to explain the presence of the strains in other arthropod species from other habitats, or even ecoregions. Conclusion Only the systematic surveys of the Wolbachia strains from entire species communities may offer the material currently lacking for understanding how Wolbachia may transfer between highly different and unrelated hosts, as well as across environmental scales.

Understanding the ecological niche to elucidate spatial strategies of the southernmost Tupinambis lizards

2013 ◽  
Vol 34 (4) ◽  
pp. 551-565 ◽  
Author(s):  
Sofía Lanfri ◽  
Valeria Di Cola ◽  
Sergio Naretto ◽  
Margarita Chiaraviglio ◽  
Gabriela Cardozo
Keyword(s):  
Species Distribution ◽  
Evolutionary Biology ◽  
Species Distribution Models ◽  
Regional Scale ◽  
Distribution Patterns ◽  
Niche Differentiation ◽  
Ecological Niches ◽  
Distribution Models ◽  
Interspecific Differences ◽  
Spatial Strategies

Understanding factors that shape ranges of species is central in evolutionary biology. Species distribution models have become important tools to test biogeographical, ecological and evolutionary hypotheses. Moreover, from an ecological and evolutionary perspective, these models help to elucidate the spatial strategies of species at a regional scale. We modelled species distributions of two phylogenetically, geographically and ecologically close Tupinambis species (Teiidae) that occupy the southernmost area of the genus distribution in South America. We hypothesized that similarities between these species might have induced spatial strategies at the species level, such as niche differentiation and divergence of distribution patterns at a regional scale. Using logistic regression and MaxEnt we obtained species distribution models that revealed interspecific differences in habitat requirements, such as environmental temperature, precipitation and altitude. Moreover, the models obtained suggest that although the ecological niches of Tupinambis merianae and T. rufescens are different, these species might co-occur in a large contact zone. We propose that niche plasticity could be the mechanism enabling their co-occurrence. Therefore, the approach used here allowed us to understand the spatial strategies of two Tupinambis lizards at a regional scale.

Research Insights: How Much Has Human Mobility Been Reduced by Social Distancing Policies in Latin America and the Caribbean?

2021 ◽  
Author(s):  
Daniel Aromi ◽  
María Paula Bonel ◽  
Julian P. Cristia ◽  
Martín Llada ◽  
Juan I. Pereira ◽  
...  
Keyword(s):  
Latin America ◽  
Human Mobility ◽  
School Closures ◽  
Social Distancing ◽  
Public Events ◽  
Percentage Points ◽  
The Caribbean ◽  
Reduced Mobility ◽  
Over Time

The lockdowns implemented in Latin America and the Caribbean in March 2020 reduced the share of people who travel more than 1 km (about 0.6 miles) per day by 10 percentage points during the 15 days following its implementation. The effects of the lockdowns declined over time: the effect amounted to 12 percentage points during the first week and to 9 percentage points during the second week of the implementation of the lockdowns. In contrast, school closures reduced mobility by only 5 percentage points, and no effects were found for bar and restaurant closures or the cancellation of public events. The results suggest that lockdowns are a tool that can produce reductions in mobility quickly. This is important given the expectation that reduced mobility slows the spread of COVID-19.

Hydration traits in cephalolichen members of the epiphytic old forest genus Lobaria (s. lat.)

2017 ◽  
Vol 49 (5) ◽  
pp. 493-506 ◽  
Author(s):  
Sara LONGINOTTI ◽  
Knut Asbjørn SOLHAUG ◽  
Yngvar GAUSLAA
Keyword(s):  
Light Intensity ◽  
The Other ◽  
Deciduous Tree ◽  
Ecological Niches ◽  
Sympatric Populations ◽  
Widespread Species ◽  
External Water ◽  
Southern Norway ◽  
Species Specific ◽  
Water Holding

AbstractThis study aims to quantify the size-dependency of important hydration traits in Lobaria amplissima, L. pulmonaria and L. virens sampled in sympatric populations on deciduous tree trunks in southern Norway, and to discuss possible implications of species-specific traits for the ecological niches of these old forest cephalolichens. Traits measured were thallus size (area and mass), specific thallus mass (STM), internal (WHCinternal) and external water-holding capacity (WHCexternal), and water content (WC) after shaking and after blotting. Lobaria amplissima had the highest WHCinternal, 2·6 times higher than L. pulmonaria with the lowest WHCinternal. WHCinternal, driven by STM, strongly depended on size. WHCexternal was 28% (L. virens) to 47% (L. pulmonaria) of the WHCinternal. Unlike WHCinternal, WHCexternal did not depend on thallus area, meaning that WHCexternal is proportionally higher for smaller compared with larger thalli. The most widespread species, L. pulmonaria, benefits from a flexible hydration strategy due to low STM, facilitating the use of more diverse water sources than the other two species that depend more on rain, particularly L. amplissima with the highest STM and thus relatively high WHCinternal. For L. virens, a combination of less specialized hydration traits and a low tolerance to higher light intensity probably jeopardizes its survival outside rainforest habitats.

Dolphin sympatric ecology in a tropical fjord: habitat partitioning by bathymetry and topography as a strategy to coexist

2007 ◽  
Vol 87 (5) ◽  
pp. 1327-1335 ◽  
Author(s):  
Lenin Oviedo
Keyword(s):  
Habitat Use ◽  
Bottlenose Dolphins ◽  
Marine Ecosystem ◽  
Sympatric Species ◽  
Ecological Niches ◽  
Habitat Partitioning ◽  
Sympatric Populations ◽  
Pacific Waters ◽  
Stenella Attenuata ◽  
Niche Factor

Sympatric species need to avoid pervasive competition to counter its suppressor effects. Dietary divergence and habitat partitioning are strategies for coexistence. Golfo Dulce is a tropical fjord located in the southern Pacific waters of Costa Rica. This embayment is characterized by the mixture of neritic and oceanic-like features. Sympatric populations of spotted and bottlenose dolphins share this particular marine ecosystem. To analyse the means of coexistence among both dolphin populations, an approach using the marginality and specialization indices of ecological niche factor analysis was used to establish separation between realized niches of both species. Habitat partitioning is sustained by difference in habitat use; bathymetry and topography separated both species' ecological niches. Dietary divergence could not be concluded because of lack of accurate dietary information. Nevertheless, it is likely to be separated by consumption of demersal prey by Tursiops truncatus, and pelagic prey by Stenella attenuata, accordingly with the differences in habitat use. Golfo Dulce could be perceived as an area of conservation importance: a geographical unit considered to contain special conservation values for both dolphin species.

scholarly journals Gene-centric intra- and inter-clade recombination in a context ofEsche-richia colisubpopulations

2017 ◽  
Author(s):  
Yu Kang ◽  
Xing Shi ◽  
Lina Yuan ◽  
Yanan Chu ◽  
Fei Chen ◽  
...  
Keyword(s):  
Early Stage ◽  
Critical Role ◽  
Ecological Niches ◽  
Phylogenetic Distance ◽  
Bacterial Genomes ◽  
Genetic Barrier ◽  
Ecological Fitness ◽  
E Coli ◽  
Genome Wide ◽  
Species Evolution

ABSTRACTRecombination is one of the most important mechanisms of prokaryotic species evolution but its exact roles are still in debate. Here we try to infer genome-wide recombination events within a species uti-lizing a dataset of 104 complete genomes ofEscherichia colifrom diverse origins, among which 45 from world-wide animal-hosts are in-house sequenced using SMRT (single-molecular real time) technology.Two major clades are identified based on evidences of ecological and physiological characteristics, as well as distinct genomic features implying scarce inter-clade genetic exchange. By comparing the synteny of identical fragments genome-widely searched for each genome pair, we achieve a fine-scale map of re-combination within the population. The recombination is rather extensive within clade, which is able to break linkages between genes but does not interrupt core genome framework and primary metabolic port-folios possibly due to natural selection for physiological compatibility and ecological fitness. Meanwhile,the recombination between clades declines drastically as the phylogenetic distance increases, generally 10-fold reduced than those of the intra-clade, which establishes genetic barrier between clades. These empirical data of recombination suggest its critical role in the early stage of speciation, where recombina-tion rate differs according to phylogentic distance. The extensive intra-clade recombination coheres sister strains into a quasi-sexual group and optimizes genes or alleles to streamline physiological activities,whereas shapely declined inter-clade recombination split the population into clades adaptive to divergent ecological niches.Significance StatementRoles of recombination in species evolution have been debated for decades due to difficulties in inferring recombination events during the early stage of speciation, especially when recombination is always complicated by frequent gene transfer events of bacterial genomes. Based on 104 high-quality completeE. coligenomes, we infer gene-centric dynamics of recombination in the formation of twoE. coliclades or subpopulations, and recombination is found to be rather intensive in a within-clade fashion, which forces them to be quasi-sexual. The recombination events can be mapped among individual genomes in the context of genes and their variations; decreased between-clade and increased intra-claderecombination engender a genetic barrier that further encourages clade-specific secondary metabolic portfolios for better environmental adaptation. Recombination is thus a major force that accelerates bacterial evolution to fit ecological diversity.

scholarly journals Genomic signals of admixture and reinforcement between two closely related species of European sepsid flies

2020 ◽  
Author(s):  
Athene Giesen ◽  
Wolf U. Blanckenhorn ◽  
Martin A. Schäfer ◽  
Kentaro K. Shimizu ◽  
Rie Shimizu-Inatsugi ◽  
...  
Keyword(s):  
Gene Flow ◽  
Dna Sequence ◽  
Species Boundaries ◽  
Adaptive Divergence ◽  
Sympatric Populations ◽  
Interspecific Gene Flow ◽  
Natural Systems ◽  
Sequence Identity ◽  
Interspecific Differences ◽  
Genome Wide

ABSTRACTInterspecific gene flow by hybridization may weaken species barriers and adaptive divergence, but can also initiate reinforcement of reproductive isolation trough natural and sexual selection. The extent of interspecific gene flow and its consequences for the initiation and maintenance of species barriers in natural systems remain poorly understood, however. To assess genome-wide patterns of gene flow between the two closely related European dung fly species Sepsis cynipsea and Sepsis neocynipsea (Diptera: Sepsidae), we tested for historical gene flow with the aid of ABBA-BABA test using whole-genome resequencing data from pooled DNA of male specimens originating from natural and laboratory populations. We contrasted genome-wide variation in DNA sequence differences between samples from sympatric populations of the two species in France and Switzerland with that of interspecific differences between pairs of samples involving allopatric populations from Estonia and Italy. In the French Cevennes, we detected a relative excess of DNA sequence identity, suggesting interspecific gene flow in sympatry. In contrast, at two sites in Switzerland, we observed a relative depletion of DNA sequence identity compatible with reinforcement of species boundaries in sympatry. Our results suggest that the species boundaries between S. cynipsea and S. neocynipsea in Europe depend on the eco-geographic context.

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