scholarly journals Biotic interactions govern genetic adaptation to toxicants

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150071 ◽  
Author(s):  
Jeremias Martin Becker ◽  
Matthias Liess
Keyword(s):  
Interspecific Competition ◽  
Intraspecific Competition ◽  
Pesticide Exposure ◽  
Biotic Interactions ◽  
Environmental Stressors ◽  
Genetic Adaptation ◽  
Resistance Allele ◽  
Selective Predation ◽  
Toxic Environment ◽  
Selection For

The genetic recovery of resistant populations released from pesticide exposure is accelerated by the presence of environmental stressors. By contrast, the relevance of environmental stressors for the spread of resistance during pesticide exposure has not been studied. Moreover, the consequences of interactions between different stressors have not been considered. Here we show that stress through intraspecific competition accelerates microevolution, because it enhances fitness differences between adapted and non-adapted individuals. By contrast, stress through interspecific competition or predation reduces intraspecific competition and thereby delays microevolution. This was demonstrated in mosquito populations ( Culex quinquefasciatus ) that were exposed to the pesticide chlorpyrifos. Non-selective predation through harvesting and interspecific competition with Daphnia magna delayed the selection for individuals carrying the ace-1 R resistance allele. Under non-toxic conditions, susceptible individuals without ace-1 R prevailed. Likewise, predation delayed the reverse adaptation of the populations to a non-toxic environment, while the effect of interspecific competition was not significant. Applying a simulation model, we further identified how microevolution is generally determined by the type and degree of competition and predation. We infer that interactions with other species—especially strong in ecosystems with high biodiversity—can delay the development of pesticide resistance.

scholarly journals Effects of Biotic Interactions, Abiotic Environments and Harvesting on the Spread of Hantavirus Infection

MATEMATIKA ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 1-14
Author(s):  
Fauzi Mohamed Yusof ◽  
Mohd Hafiz Mohd ◽  
Yazariah Mohd Yatim ◽  
Ahmad Izani Md. Ismail
Keyword(s):  
Infectious Diseases ◽  
Alien Species ◽  
Interspecific Competition ◽  
Environmental Conditions ◽  
Biocontrol Agent ◽  
Biotic Interactions ◽  
Numerical Continuation ◽  
Hantavirus Infection ◽  
Potential Biocontrol Agent ◽  
Spread Of Infection

In this paper, the combined influences of biotic interactions, environmental components and harvesting strategy on the spread of Hantavirus are investigated. By employing a multi-species model consisting of (susceptible and infected) rodents and alien species, we show that interspecific competition from alien species has an effect in reducing the spread of infection, and this species could be employed as a potential biocontrol agent. Our analysis using numerical continuation and simulation also reveals the conditions under which Hantavirus infection occurs and disappears as the environmental conditions and the intensity of harvesting change. Without harvesting, infection emerges when environments are conducive. Inclusion of moderate harvesting in favourable environments can lead to disappearance of infection among rodent species. However, as the intensity of harvesting increases, this situation can cause extinction of all rodents species and consequently, jeopardise biodiversity. Overall, our results demonstrate how the interplay of different factors can combine to determine the spread of infectious diseases.

Habitat use, interspecific competition and phylogenetic history shape the evolution of claw and toepad morphology in Lesser Antillean anoles

2020 ◽  
Vol 129 (3) ◽  
pp. 630-643 ◽  
Author(s):  
Michael L Yuan ◽  
Catherine Jung ◽  
Marvalee H Wake ◽  
Ian J Wang
Keyword(s):  
Interspecific Competition ◽  
Functional Traits ◽  
Functional Morphology ◽  
Biotic Interactions ◽  
Single Species ◽  
Morphometric Data ◽  
Opposite Pattern ◽  
Geometric Morphometric ◽  
Vegetation Use ◽  
Selective Forces

Abstract Ecologically functional traits are the product of several, at times opposing, selective forces. Thus, ecomorphological patterns can be disrupted locally by biotic interactions, such as competition, and may not be consistent across lineages. Here, we studied the evolution of claws and toepads in relationship to macrohabitat (vegetation), use of structural microhabitat (perch height) and congeneric competition for two distantly related Lesser Antillean anole clades: the Anolis bimaculatus and Anolis roquet series. We collected univariate and geometric morphometric data from 254 individuals across 22 species to test the hypotheses that functional morphology should covary with both vegetation and perch height and that the presence of a competitor may disrupt such covariation. Our data showed predictable associations between morphology and macrohabitat on single-species islands but not when a congeneric competitor was present. The outcomes of competition differed between series, however. In the A. bimaculatus series, species with a sympatric congener diverged in claw and toepad traits consistent with functional predictions, whereas A. roquet series anoles showed either no association between habitat and morphology or the opposite pattern. Our results demonstrated that ecomorphological patterns across macrohabitats can be disrupted by competition-driven microhabitat partitioning and that specific morphological responses to similar ecological pressures can vary between lineages.

Competition betweenElymus elymoidesandTaeniatherum caput-medusae

Weed Science ◽  
1999 ◽  
Vol 47 (6) ◽  
pp. 720-728 ◽  
Author(s):  
David W. Clausnitzer ◽  
Michael M. Borman ◽  
Douglas E. Johnson
Keyword(s):  
Soil Moisture ◽  
Interspecific Competition ◽  
Seed Production ◽  
Intraspecific Competition ◽  
Field Experiments ◽  
Block Design ◽  
Low Oxygen ◽  
Competitive Effects ◽  
Growing Seasons ◽  
Randomized Block Design

Two field experiments were conducted from 1993–1994 through 1995–1996 growing seasons in Harney County, OR, to determine the relative competitive abilities ofElymus elymoides(squirreltail) a native perennial range grass, andTaeniatherum caput-medusae(medusahead), an exotic annual grass weed. The 1993–1994 growing season was very dry, 1994–1995 was dry, and 1995–1996 was wetter than average. One experiment tested seedlings vs. seedlings in each of three seasons. The second experiment tested seedlings plus second- and third-year establishedE. elymoidesplants vs. 77caput-medusaeover 2 yr. Biomass, seed production, and soil moisture utilization 15, 30, 45, and 60 cm deep by the two species were measured. A randomized block design with factorial arrangement was used, with 25 2.25-m2plots per block. Initial seeding densities of each species were 0, 10, 74, 550, and 4,074 seeds m−2in all combinations of density. In the seedling vs. seedling experiment, intraspecific competition by 77caput-medusaeon itself was always significant (P ≤ 0.10) for both biomass and seed production. Interspecific competition byE. elymoidesseedlings onT. caput-medusaebiomass and seed production was not significant (P ≥ 0.10) in 2 of 3 yr and was always less than intraspecific competition by 77caput-medusae. Only 0.4% ofE. elymoidesseed germinated, and no seed was produced in the very dry first year, but 84% of remaining seed was viable for the next year, which had better moisture conditions for germination and establishment. Interspecific competition affected (P ≤ 0.10)E. elymoidesseedling biomass and seed production throughout the study. Intraspecific competition affected (P ≤ 0.10) seedlingE. elymoidesseed production in the dry year but not in the wetter than average year. In the matureE. elymoidesexperiment, intraspecific competition byT. caput-medusaeon weight and seed production per plant was greater than interspecific competition fromE. elymoides. Seedling/matureE. elymoidesreducedT. caput-medusaeweight per plant in the dry year but the effect was not biologically significant. Larger, matureEelymoidesplants produced 600 to 3,000 seeds per plant during the wet year; neither intra- nor interspecific competition was a factor.Taeniatherum caput-medusaewas better able to access deeper soil moisture and was more aggressive at extracting soil moisture than wereE. elymoidesseedlings in the wet year. Cold soils and low oxygen due to wet soils may have restrictedE. elymoidesseedling root activity. MatureE. elymoidesplants did not appear restricted by cold soils or low oxygen. Established second- and third-yearE. elymoidesplants were able to compete for soil moisture down to 45 cm. The generally greater interspecific competitive effects ofT. caput-medusaeonE. elymoidesthan vice versa suggested that it will be difficult to establish anE. elymoidesstand in an existingT. caput-medusaecommunity without first suppressingT. caput-medusae. IndividualE. elymoidesplants did establish and were productive with and withoutT. caput-medusaecompetition.

Plant Water Stress of Soybean (Glycine max) and Common Cocklebur (Xanthium pensylvanicum): A Comparison Under field Conditions

Weed Science ◽  
1979 ◽  
Vol 27 (3) ◽  
pp. 285-289 ◽  
Author(s):  
H. D. Scott ◽  
R. D. Geddes
Keyword(s):  
Glycine Max ◽  
Water Stress ◽  
Interspecific Competition ◽  
Intraspecific Competition ◽  
Vegetative Growth ◽  
Species Differences ◽  
Plant Water ◽  
Plant Water Stress ◽  
Diffusive Resistance ◽  
Early Afternoon

The study was conducted to determine the seasonal and diurnal water stress of soybeans [Glycine max (L.) Merr. ‘Lee 74′] grown under intraspecific competition (competition between plants of the same species) and interspecific competition (competition between plants of different species) with common cocklebur (Xanthium pensylvanicum Wallr.). Midday xylem potentials decreased as the season progressed and were lower in common cocklebur during vegetative growth of soybean and in soybean during reproductive growth. For a given species differences in xylem potential due to mode of competition were small. In the diurnal studies xylem potential for each species decreased to a minimum in the early afternoon but recovered to the original pre-dawn values at night. As the season progressed leaf xylem potential (a) decreased at a greater rate, (b) decreased sooner in the day, and (c) recovered at a slower rate. It was shown that differences in xylem potential between soybean and common cocklebur on a given day were small. Greater diffusive resistance values generally were found with soybean than with common cocklebur and with each species grown under interspecific competition.

Competition between endoparasitic nematodes and effect on biomass of Ammophila arenaria (marram grass) as affected by timing of inoculation and plant age

Nematology ◽  
2005 ◽  
Vol 7 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Wim van der Putten ◽  
Henk Duyts ◽  
E. Pernilla Brinkman
Keyword(s):  
Interspecific Competition ◽  
Intraspecific Competition ◽  
Plant Biomass ◽  
Nematode Species ◽  
Pratylenchus Penetrans ◽  
Agricultural Systems ◽  
Ammophila Arenaria ◽  
Marram Grass ◽  
Natural Dune ◽  
Dune Grass

AbstractWe studied the effects of intra- and interspecific competition on the abundance of endoparasitic nematodes and assessed the consequences for biomass production of the natural dune grass Ammophila arenaria. Pratylenchus penetrans was limited by intraspecific competition and it suppressed the abundance of Heterodera arenaria, whilst the interaction between H. arenaria and Meloidogyne maritima was neutral. Pratylenchus penetrans and H. arenaria reduced plant biomass, whereas M. maritima did not. Plant biomass was not differently affected by adding one or two nematode species. When added to older plants, numbers of H. arenaria and M. maritima were higher but numbers of P. penetrans were lower, resulting in less reduction of plant biomass. We discuss our results on this natural system with respect to patterns of interspecific nematode competition observed in agricultural systems.

Influence of Phosphorus Fertility on Intra- and Interspecific Interference between Lettuce (Lactuca sativa) and Spiny Amaranth (Amaranthus spinosus)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 574-578 ◽  
Author(s):  
James W. Shrefler ◽  
Donn G. Shilling ◽  
Joan A. Dusky ◽  
Barry J. Brecke
Keyword(s):  
Interspecific Competition ◽  
Lactuca Sativa ◽  
Intraspecific Competition ◽  
Relative Yield ◽  
Shoot Biomass ◽  
Low Density ◽  
Yield Analysis ◽  
Amaranthus Spinosus ◽  
Affected Relative

Greenhouse studies were conducted to determine the effect of phosphorus (P) fertility on intra- and interspecific competition between lettuce and spiny amaranth for 4 wk after emergence. Total lettuce shoot biomass per pot and weight per plant increased 39 and 44% in response to increased P fertility, respectively. P fertility had no impact on growth of spiny amaranth. Total shoot biomass of spiny amaranth increased with increasing density from four to eight plants, however, lettuce did not. Total shoot biomass of both species increased as density increased from 4 to 16 plants. Spiny amaranth, but not lettuce, weight per plant decreased in response to intraspecific competition. Reciprocal yield analysis showed that spiny amaranth produced 2.4 times more biomass than lettuce when competing intraspecifically and four times more biomass under interspecific competition. Lettuce weight per plant was not affected. Relative yield analysis indicated that spiny amaranth was more competitive than lettuce regardless of P fertility. However, increased P fertility increased competitiveness of lettuce. Relative crowding coefficients indicated that spiny amaranth at the low density with low P fertility was 33 times more competitive than lettuce. Addition of P caused lettuce and spiny amaranth to be equally competitive at the lowest density; however, at the highest density, spiny amaranth was 4 tunes more competitive than lettuce regardless of additional P.

scholarly journals Biotic interactions are the dominant drivers of phylogenetic and functional structure in bird communities along a tropical elevational gradient

The Auk ◽  
2019 ◽  
Vol 136 (4) ◽  
Author(s):  
Andy J Boyce ◽  
Subir Shakya ◽  
Frederick H Sheldon ◽  
Robert G Moyle ◽  
Thomas E Martin
Keyword(s):  
Community Structure ◽  
Interspecific Competition ◽  
Species Turnover ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Relative Strength ◽  
Resource Acquisition ◽  
Similar Species ◽  
Cold Temperatures ◽  
Tropical Mountains

Abstract Understanding how biotic and abiotic interactions influence community assembly and composition is a fundamental goal in community ecology. Addressing this issue is particularly tractable along elevational gradients in tropical mountains that feature substantial abiotic gradients and rates of species turnover. We examined elevational patterns of avian community structure on 2 mountains in Malaysian Borneo to assess changes in the relative strength of biotic interactions and abiotic constraints. In particular, we used metrics based on (1) phylogenetic relatedness and (2) functional traits associated with both resource acquisition and tolerance of abiotic challenges to identify patterns and causes of elevational differences in community structure. High elevation communities were composed of more phylogenetically and functionally similar species than would be expected by chance. Resource acquisition traits, in particular, were clustered at high elevations, suggesting low resource and habitat diversity were important drivers of those communities. Traits typically associated with tolerance of cold temperatures and low atmospheric pressure showed no elevational patterns. All traits were neutral or overdispersed at low elevations suggesting an absence of strong abiotic filters or an increased influence of interspecific competition. However, relative bill size, which is important for thermoregulation, was larger in low elevation communities, suggesting abiotic factors were also influential there. Regardless of metric, clustered and neutral communities were more frequent than overdispersed communities overall, implying that interspecific competition among close relatives may not be a pervasive driver of elevational distribution and community structure of tropical birds. Overall, our analyses reveal that a diverse set of predominantly biotic factors underlie elevational variation in community structure on tropical mountains.

scholarly journals Behavioural mechanisms of competition in small dasyurid marsupials

2000 ◽  
Vol 48 (5) ◽  
pp. 561 ◽  
Author(s):  
Joanne Righetti ◽  
Barry J. Fox ◽  
David B. Croft
Keyword(s):  
Body Size ◽  
Interspecific Competition ◽  
Intraspecific Competition ◽  
Activity Patterns ◽  
Interference Competition ◽  
Avoidance Behaviour ◽  
Antechinus Stuartii ◽  
Competitive Behaviour ◽  
Spatio Temporal ◽  
Interspecific Comparisons

The competitive behaviour of three species of small dasyurid marsupial, Antechinus swainsonii, Antechinus stuartii and Sminthopsis murina, was assessed in specially designed enclosures and smaller encounter cages, by videotaping the activity of pairs of animals, both as conspecifics and members of different species (except for A. swainsoni versus S. murina). Spatio-temporal analyses revealed differences in activity patterns and interactions within and between the species. Interference competition occurred in all intraspecific and interspecific comparisons tested. Encounter competition was judged to be the mechanism operating as all animals entered into interactions with other individuals. Encounters were particularly prevalent within Antechinus, indicating that they were more social than the relatively solitary Sminthopsis. Avoidance behaviour occurred between the two Antechinus species and this may enable them to coexist, so that this mechanism may be considered to be avoidance competition. The smaller competitor, S. murina, showed avoidance of the larger A. stuartii. Intraspecific competition was judged to be stronger than interspecific competition, but the latter could have more severe consequences, with the death of the smaller species occurring in some situations. This highlighted the asymmetric nature of competition, with body size determining the outcome of interactions between species.

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