Prevalence of mutualism in a simple model of microbial co-evolution

Evolutionary transitions among ecological interactions are widely known, although their detailed dynamics remain absent for most population models. Adaptive dynamics has been used to illustrate how the parameters of population models might shift through evolution but within an ecological regime. Here we use adaptive dynamics combined with a generalised logistic model of population dynamics to show that transitions of ecological interactions might appear as a consequence of evolution. To this purpose, we introduce a two-microbial toy model in which population parameters are determined by a bookkeeping of resources taken from (and excreted to) the environment, as well as from the byproducts of the other species. Despite its simplicity, this model exhibits all sorts of ecological transitions, some of which resemble those found in nature. Overall, the model shows a clear trend toward the emergence of mutualism.

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Natural Trypanosoma cruzi infection in dogs of endemic areas of the Argentine Republic

Revista do Instituto de Medicina Tropical de São Paulo ◽

10.1590/s0036-46651989000200001 ◽

1989 ◽

Vol 31 (2) ◽

pp. 63-70 ◽

Cited By ~ 11

Author(s):

Marta A. Lauricella ◽

Angel J. Sinagra ◽

Irene Paulone ◽

Adelina R. Riarte ◽

Eisa L. Segura

Keyword(s):

Population Dynamics ◽

Rural Area ◽

Human Population ◽

The Other ◽

Population Parameters ◽

Sedentary Population ◽

Infection Pattern ◽

Canine Population ◽

Argentine Republic ◽

Cruzi Infection

The population dynamics and the prevalence of chagasic infection of 352 dogs living in 108 rural houses infested by triatomines were studied. The region was divided into three sections according to increasing distances to an urban area. Each animal was identified by means of its particular characteristics and built, and its owners gave information about its habits. By means of xenodiagnosis, serology and ECG studies, prevalences of infection, parasitological-serological correlation, percentage of altered electrocardiographic outlines and percentage of houses with parasitemic dogs, were determined. The rural area showed a characteristic T. cruzi infection pattern and differences in the canine population parameters with respect to the other areas were observed: a higher proportion of puppies than adult dogs, a more sedentary population, higher prevalences of infection, as measured by xenodiagnosis, in dogs, and the highest proportion of bedroom insects infected with T. cruzi. It is assumed that the sedentary characteristics of the human population in that rural area impinge in the blood offer to the triatomine population, and the high percentage of parasitemic dogs of the area, contribute to the rise of "kissing ougs" infected with T. cruzi found in bedrooms.

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The influence of two wildfires and biological control agents on the population dynamics of Melaleuca quinquenervia in a seasonally inundated wetland

Invasive Plant Science and Management ◽

10.1017/inp.2021.4 ◽

2021 ◽

Vol 14 (1) ◽

pp. 3-8

Author(s):

Philip W. Tipping ◽

Melissa R. Martin ◽

Jeremiah R. Foley ◽

Ryan M. Pierce ◽

Lyn A. Gettys

Keyword(s):

Biological Control ◽

Population Dynamics ◽

Seedling Recruitment ◽

Additional Treatment ◽

Seed Rain ◽

The Other ◽

Melaleuca Quinquenervia ◽

Biological Control Agents ◽

Seedling Mortality ◽

Sapling Growth

AbstractThe potential of Melaleuca quinquenervia (Cav.) S.T. Blake to reinvade cleared areas was evaluated over a 13-yr period that included two wildfires and the introduction of biological control agents. The first wildfire occurred in 1998 and was followed by a mean of 591.5 recruited seedlings m−2. Recruits from that fire were cleared 7 yr later in July 2005 for a second experiment to evaluate seedling recruitment into cleared areas. Seed rain, seedling recruitment and mortality, and sapling growth rates were measured in four plots located around individual large reproductive trees. A second natural wildfire in 2007 burned through those plots, leading to increases in seed rain followed by a pulse in recruitment of 21.04 seedlings m−2, 96.5% fewer than after the 1998 fire. Recruits in half of the plots around each tree were then treated with regular applications of an insecticide to restrict herbivory by biological control agents, while herbivory was not restricted in the other half. There was no difference in seedling mortality between treatments 1,083 d post-fire (2007) with 96.6% seedling mortality in the unrestricted herbivory treatment and 89.4% mortality in the restricted herbivory treatment. Recruits subjected to the restricted herbivory treatment grew taller than those in the unrestricted herbivory treatment, 101.3 cm versus 37.4 cm. Many of the recruits were attacked by the biological control agents, which slowed their growth. Although solitary M. quinquenervia trees retain some capacity to reinvade areas under specific circumstances, there was a downward trend in their overall invasiveness at this site, with progressively smaller recruitment cohorts due to biological control agents. Land managers should prioritize removing large reproductive trees over treating recently recruited populations, which can be left for many years for the biological control agents to suppress before any additional treatment would be needed.

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Population parameters and the relationships between environmental factors and abundance of the Acetes americanus shrimp (Dendrobranchiata: Sergestidae) near a coastal upwelling region of Brazil

Brazilian Journal of Oceanography ◽

10.1590/s1679-87592015086206303 ◽

2015 ◽

Vol 63 (3) ◽

pp. 229-238

Author(s):

Ana Paula Freitas dos Santos ◽

Sabrina Morilhas Simões ◽

Gabriel Lucas Bochini ◽

Cinthia Helena Costa ◽

Rogerio Caetano da Costa

Keyword(s):

Population Dynamics ◽

Sexual Dimorphism ◽

Environmental Factors ◽

Primary Productivity ◽

Low Temperatures ◽

Coastal Upwelling ◽

Statistical Correlation ◽

Individual Growth ◽

Otter Trawl ◽

Population Parameters

AbstractThe population dynamics of Acetes americanus was investigated, focusing on the sex ratio, individual growth, longevity, recruitment and relationship between abundance and environmental factors in the region of Macaé, strongly influenced by coastal upwelling. Otter trawl net samplings were performed from July 2010 to June 2011 at two points (5 m and 15 m). Nearly 19,500 specimens, predominantly females (77.15%), were captured. Their sizes, larger than that of males, indicated sexual dimorphism. Shrimps at lower latitudes present larger sizes and longer longevity than those from higher latitudes. This difference is probably due to low temperatures and high primary productivity. Though no statistical correlation was found between abundance and environmental factors, the species was more abundant in temperatures closer to 20.0º C and in months with high chlorophyll-a levels. Due to the peculiar characteristics of this region, A. americanusshowed greater differences in size and longevity than individuals sampled in other studies undertaken in the continental shelf of Southeast Brazil.

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The population dynamics of metacercariae of Apatemon gracilis (Trematoda: Digenea) in three species of lake-dwelling leeches

Parasitology ◽

10.1017/s0031182000081221 ◽

1986 ◽

Vol 93 (3) ◽

pp. 517-530 ◽

Cited By ~ 8

Author(s):

S. M. Spelling ◽

J. O. Young

Keyword(s):

Population Dynamics ◽

Relative Density ◽

Sexual Maturity ◽

Egg Production ◽

Seasonal Pattern ◽

Distinct Pattern ◽

The Other ◽

Mean Intensity ◽

Density Values ◽

Host Mortality

SUMMARYMonthly samples of the leeches Erpobdella octoculata, Glossiphonia complanata and Helobdella stagnalis were taken over a two-year period from an eutrophic, English lake to detect metacercariae of the trematode, Apatemon gracilis. In each cohort of each of the three leeches, prevalence was low in young individuals, rose to a peak in autumn/winter, and then declined until the cohort had almost died out; in E. octoculata and H. stagnalis a final brief increase occurred. Mean intensity and relative density values followed a similar seasonal pattern of change to that of prevalence in these last two species, but in G. complanata values fluctuated irregularly with no distinct pattern. The frequency distribution of the parasite in G. complanata was highly over-dispersed, but less so in the other two species. Infected E. octoculata reached sexual maturity. The parasite reduced egg production in G. complanata and H. stagnalis, but only by maximum values of 2·5 and 9% respectively. This reduction in fecundity is low compared to the subsequent high mortality, at 95% or more, of newly recruited young from as yet unidentified causes. Parasite-related host mortality was difficult to assess in young leeches, but there was some evidence for its occurrence in older leeches of E. octoculata and H. stagnalis. However, this is unlikely to play a prominent role in the control and regulation of lacustrine leech populations.

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Quantifying the effect of genetic, environmental and individual demographic stochastic variability for population dynamics in Plantago lanceolata

Scientific Reports ◽

10.1038/s41598-021-02468-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ulrich K. Steiner ◽

Shripad Tuljapurkar ◽

Deborah A. Roach

Keyword(s):

Population Dynamics ◽

Population Growth ◽

Population Change ◽

Adaptive Dynamics ◽

Plantago Lanceolata ◽

Environmental Parameters ◽

Experimental Population ◽

Stochastic Variation ◽

Survival And Reproduction ◽

Stochastic Events

AbstractSimple demographic events, the survival and reproduction of individuals, drive population dynamics. These demographic events are influenced by genetic and environmental parameters, and are the focus of many evolutionary and ecological investigations that aim to predict and understand population change. However, such a focus often neglects the stochastic events that individuals experience throughout their lives. These stochastic events also influence survival and reproduction and thereby evolutionary and ecological dynamics. Here, we illustrate the influence of such non-selective demographic variability on population dynamics using population projection models of an experimental population of Plantago lanceolata. Our analysis shows that the variability in survival and reproduction among individuals is largely due to demographic stochastic variation with only modest effects of differences in environment, genes, and their interaction. Common expectations of population growth, based on expected lifetime reproduction and generation time, can be misleading when demographic stochastic variation is large. Large demographic stochastic variation exhibited within genotypes can lower population growth and slow evolutionary adaptive dynamics. Our results accompany recent investigations that call for more focus on stochastic variation in fitness components, such as survival, reproduction, and functional traits, rather than dismissal of this variation as uninformative noise.

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How Quickly are Road-killed Snakes Scavenged? Implications for Underestimates of Road Mortality

Journal of North Carolina Academy of Science ◽

10.7572/2167-5880-127.2.184 ◽

2011 ◽

Vol 127 (2) ◽

pp. 184-188 ◽

Cited By ~ 3

Author(s):

BRETT A. DEGREGORIO ◽

THOMAS E. HANCOCK ◽

DAVID J. KURZ ◽

SAM YUE

Keyword(s):

United States ◽

Population Dynamics ◽

Community Composition ◽

The United States ◽

The Other ◽

Road Mortality ◽

Correction Factors ◽

Significant Extent ◽

Removal Time ◽

Maritime Forest

Abstract Annually, millions of snakes are killed on roads in the United States. Because of their potential abundance and ease of collection, many researchers have used road-killed snakes to examine community composition, movement patterns, and population dynamics. However, few previous studies have accounted for snake carcasses that are removed from roads by scavengers. Snake carcasses were placed at randomly selected locations along 2 km of road, one traversing maritime forest and the other surrounded by dune habitat. Carcasses in forested habitat were removed more often (100% vs 40%) and more quickly (8 hr vs 11 hr) than those placed in dune habitat. Half of the carcasses (50%) were removed within eight hours of placement and all carcasses were removed at night. Species and size of carcasses did not affect removal time. Removal time and scavenging intensity of snake carcasses most likely varies across regions and habitats. Furthermore, because scavenging appears to occur quickly and to such a significant extent, it may confound results of studies examining patterns of road-mortality. Thus, investigators that use data from road-killed snakes would benefit from a concurrent investigation of scavenging and application of appropriate correction factors to avoid underestimation of snake mortality.

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Articulatory setting, articulatory symmetry, and production mechanisms for Catalan consonant sequences

Romance Phonetics and Phonology ◽

10.1093/oso/9780198739401.003.0009 ◽

2018 ◽

pp. 146-158

Author(s):

Daniel Recasens ◽

Meritxell Mira

Keyword(s):

The Other ◽

Clear Trend ◽

Acoustic Data ◽

Production Strategies ◽

Production Mechanisms ◽

Level Analysis

This study reports articulatory and acoustic data for three Catalan dialects (Eastern, Western, Valencian), showing that the sequences /tsʃ/ and /sʃ/, and /tʃs/ and /ʃs/, are implemented through analogous production mechanisms and therefore that fricative+fricative and affricate+fricative sequences behave symmetrically at the articulatory level. Analysis results also reveal a clear trend for regressive assimilation in the case of /(t)sʃ/ and for blending or a two-target realization in the case of /(t)ʃs/; differences in degree of articulatory complexity among the segmental sequences under analysis account for these production strategies. Moreover, the final phonetic outcome is strongly dependent on the dialect-dependent articulatory differences in fricative articulation; thus, in Valencian, /(t)sʃ / may undergo regressive assimilation or blending and /(t)ʃs/ regressive assimilation, owing to a more anterior lingual constriction for /ʃ/ than in the other dialects.

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Linnaeus, Carl von (1707–78)

Routledge Encyclopedia of Philosophy ◽

10.4324/9780415249126-q059-1 ◽

2018 ◽

Author(s):

P.F. Stevens

Keyword(s):

Classification System ◽

Natural System ◽

The Other ◽

European Countries ◽

Ecological Interactions ◽

Wide Range ◽

Divine Retribution ◽

The World ◽

Artificial Classification

Linnaeus was educated in Sweden, and became a doctor of medicine in Harderwijk, Holland, in 1735. He visited other European countries then, but he never left Sweden after his return in 1738. After practising as a physician in Stockholm, he moved to Uppsala University as professor of medicine and botany in 1741. He articulated four different but complementary ways of understanding nature – through two kinds of classification, and through what can be called developmental and functional/ecological interactions. Linnaeus is best known for his classificatory work, for which he received material from all over the world. His classificatory precepts are elaborated in the Philosophia botanica of 1751, an enlarged version of the 365 aphorisms of his Fundamenta botanica of 1735; the other aspects of his work are diffused through his writings. His artificial classification system, initially very popular, was replaced by the ’natural’ system, more slowly in botany than in zoology, and more slowly in England than in some other countries. Current biological nomenclature is based on his Species plantarum, edition 1 (for plants), and Systema naturae, edition 10 (for animals). His codification of botanical terms remains influential. Almost 200 dissertations, most written by Linnaeus, were defended by his students. In these and other less well-known works, including the unpublished Nemesis divina (Stories of Divine Retribution), he covered a wide range of subjects. Quinarian thinking is noticeable in Linnaeus’ work – there are five ranks in systems, five years’ growth in flowers – and in some of the occult works that he knew. He also shows a strong combinatorial bent and a tendency to draw close analogies between the parts of animals and plants.

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Contrasting effects of the onset of spring on reproductive success of Arctic-nesting geese

The Auk ◽

10.1093/auk/ukz063 ◽

2019 ◽

Vol 137 (1) ◽

Cited By ~ 4

Author(s):

Bart A Nolet ◽

Kees H T Schreven ◽

Michiel P Boom ◽

Thomas K Lameris

Keyword(s):

Population Dynamics ◽

Late Onset ◽

The Other ◽

Second Phase ◽

Combined Effects ◽

Negative Effects ◽

Early Snowmelt ◽

The One ◽

Winter Flocks ◽

Breeding Propensity

Abstract Breeding output of geese, measured as the proportion of juveniles in autumn or winter flocks, is lower in years with a late onset of spring in some species, but higher in at least one other species. Here we argue that this is because the timing of spring affects different stages of the reproductive cycle differently in different species. Because the effects on 2 different stages are opposite, the combined effects can result in either a positive or a negative overall effect. These stages are the pre-laying, laying, and nesting phase on the one hand; and the hatchling, fledgling, and juvenile phase on the other hand. The first phase is predominantly positively affected by an early snowmelt, with higher breeding propensity, clutch size, and nest success. The second phase in contrast is negatively affected by early snowmelt because of a mismatch with a nutrient food peak, leading to slow gosling growth and reduced survival. We argue that recognition of this chain of events is crucial when one wants to predict goose productivity and eventually goose population dynamics. In a rapidly warming Arctic, the negative effects of a mismatch might become increasingly important.

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