scholarly journals Host-Parasite Co-Evolution in Real-Time: Changes in Honey Bee Resistance Mechanisms and Mite Reproductive Strategies

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 120
Author(s):  
Arrigo Moro ◽  
Tjeerd Blacquière ◽  
Delphine Panziera ◽  
Vincent Dietemann ◽  
Peter Neumann
Keyword(s):  
Honey Bee ◽  
Host Resistance ◽  
Reproductive Strategies ◽  
Temporal Variations ◽  
Phenotypic Traits ◽  
Holistic View ◽  
Mite Reproduction ◽  
Adaptive Shifts ◽  
Host Parasite ◽  
Over Time

Co-evolution is a major driving force shaping the outcome of host-parasite interactions over time. After host shifts, the lack of co-evolution can have a drastic impact on novel host populations. Nevertheless, it is known that Western honey bee (Apismellifera) populations can cope with host-shifted ectoparasitic mites (Varroa destructor) by means of natural selection. However, adaptive phenotypic traits of the parasites and temporal variations in host resistance behavior are poorly understood. Here, we show that mites made adaptive shifts in reproductive strategy when associated with resistant hosts and that host resistance traits can change over time. In a fully-crossed field experiment, worker brood cells of local adapted and non-adapted (control) A.mellifera host colonies were infested with mites originating from both types of host colonies. Then, mite reproduction as well as recapping of cells and removal of infested brood (i.e., Varroa Sensitive Hygiene, VSH) by host workers were investigated and compared to data from the same groups of host colonies three years earlier. The data suggest adaptive shifts in mite reproductive strategies, because mites from adapted hosts have higher probabilities of reproduction, but lower fecundity, when infesting their associated hosts than mites in treated colonies. The results confirm that adapted hosts can reduce mite reproductive success. However, neither recapping of cells nor VSH were significantly expressed, even though the latter was significantly expressed in this adapted population three years earlier. This suggests temporal variation in the expression of adaptive host traits. It also appears as if mechanisms not investigated here were responsible for the reduced mite reproduction in the adapted hosts. In conclusion, a holistic view including mite adaptations and studies of the same parasite/host populations over time appears overdue to finally understand the mechanisms enabling survival of V.destructor-infested honey bee host colonies.

scholarly journals Identifying Spatial and Temporal Variations in Concrete Bridges with Ground Penetrating Radar Attributes

2021 ◽  
Vol 13 (9) ◽  
pp. 1846
Author(s):  
Vivek Kumar ◽  
Isabel M. Morris ◽  
Santiago A. Lopez ◽  
Branko Glisic
Keyword(s):  
Compressive Strength ◽  
Ground Penetrating Radar ◽  
Material Properties ◽  
Temporal Variations ◽  
Concrete Bridges ◽  
Spatial And Temporal Variation ◽  
Reflected Waves ◽  
Ground Penetrating ◽  
Over Time

Estimating variations in material properties over space and time is essential for the purposes of structural health monitoring (SHM), mandated inspection, and insurance of civil infrastructure. Properties such as compressive strength evolve over time and are reflective of the overall condition of the aging infrastructure. Concrete structures pose an additional challenge due to the inherent spatial variability of material properties over large length scales. In recent years, nondestructive approaches such as rebound hammer and ultrasonic velocity have been used to determine the in situ material properties of concrete with a focus on the compressive strength. However, these methods require personnel expertise, careful data collection, and high investment. This paper presents a novel approach using ground penetrating radar (GPR) to estimate the variability of in situ material properties over time and space for assessment of concrete bridges. The results show that attributes (or features) of the GPR data such as raw average amplitudes can be used to identify differences in compressive strength across the deck of a concrete bridge. Attributes such as instantaneous amplitudes and intensity of reflected waves are useful in predicting the material properties such as compressive strength, porosity, and density. For compressive strength, one alternative approach of the Maturity Index (MI) was used to estimate the present values and compare with GPR estimated values. The results show that GPR attributes could be successfully used for identifying spatial and temporal variation of concrete properties. Finally, discussions are presented regarding their suitability and limitations for field applications.

scholarly journals Dynamic capabilities as (workable) management systems theory

2018 ◽  
Vol 24 (3) ◽  
pp. 359-368 ◽  
Author(s):  
David J Teece
Keyword(s):  
Systems Theory ◽  
Dynamic Capabilities ◽  
Systems Approach ◽  
Business Environment ◽  
Academic Disciplines ◽  
Management Systems ◽  
Holistic View ◽  
Individual Enterprise ◽  
Management Leadership ◽  
Over Time

AbstractIn management studies, systems theory is an underexplored construct consistent with the dynamic capabilities framework. The systems approach received attention from management scholars in the middle of the last century, but, since then, has been largely abandoned. Meanwhile, academic disciplines have continued to narrow their focus. The capabilities and systems frameworks both adopt a holistic view that calls for all elements of an organization to be in alignment, and both recognize the importance of some form of learning for the purpose of adaptation. Dynamic capabilities go further by recognizing that organizations not only adapt to the business environment, they often try to shape it, too. While systems theory emphasizes internal stability over time and homogeneity across similar systems, dynamic capabilities include an explicit role for management/leadership that allows systemic change to start from within, which is the source of heterogeneity across firms. Dynamic capabilities are part of a system that includes resources and strategy. Together they determine the degree of competitive advantage an individual enterprise can gain over its rivals.

scholarly journals Tick-Borne Encephalitis Virus: Seasonal and Annual Variation of Epidemiological Parameters Related to Nymph-to-Larva Transmission and Exposure of Small Mammals

Pathogens ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 518
Author(s):  
Laure Bournez ◽  
Gerald Umhang ◽  
Marie Moinet ◽  
Céline Richomme ◽  
Jean-Michel Demerson ◽  
...  
Keyword(s):  
Small Mammals ◽  
Temporal Variations ◽  
Encephalitis Virus ◽  
Myodes Glareolus ◽  
Mountain Forest ◽  
Annual Variations ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus ◽  
Over Time ◽  
Epidemiological Parameters

A greater knowledge of the ecology of the natural foci of tick-borne encephalitis virus (TBEV) is essential to better assess the temporal variations of the risk of tick-borne encephalitis for humans. To describe the seasonal and inter-annual variations of the TBEV-cycle and the epidemiological parameters related to TBEV nymph-to-larva transmission, exposure of small mammals to TBEV, and tick aggregation on small mammals, a longitudinal survey in ticks and small mammals was conducted over a 3-year period in a mountain forest in Alsace, eastern France. TBEV prevalence in questing nymphs was lower in 2013 than in 2012 and 2014, probably because small mammals (Myodes glareolus and Apodemus flavicollis) were more abundant in 2012, which reduced tick aggregation and co-feeding transmission between ticks. The prevalence of TBEV in questing nymphs was higher in autumn than spring. Despite these variations in prevalence, the density of infected questing nymphs was constant over time, leading to a constant risk for humans. The seroprevalence of small mammals was also constant over time, although the proportion of rodents infested with ticks varied between years and seasons. Our results draw attention to the importance of considering the complex relationship between small mammal densities, tick aggregation on small mammals, density of infected questing nymphs, and prevalence of infected nymphs in order to forecast the risk of TBEV for humans.

Community-Level Interactions and Disease Dynamics

2021 ◽  
pp. 145-170
Author(s):  
Karen D. McCoy
Keyword(s):  
Local Area ◽  
Community Level ◽  
Disease Dynamics ◽  
Biological Communities ◽  
Natural Systems ◽  
Parasite Communities ◽  
Almost All ◽  
Host Parasite ◽  
Natural Communities ◽  
Over Time

An ecological community includes all individuals of all species that interact within a single patch or local area of habitat. Understanding the outcome of host–parasite interactions and predicting disease dynamics is particularly challenging at this biological scale because the different component species interact both directly and indirectly in complex ways. Current shifts in biodiversity due to global change, and its associated modifications to biological communities, will alter these interactions, including the probability of disease emergence, its dynamics over time, and its community-level consequences. Birds are integral component species of almost all natural communities. Due to their ubiquity and specific life history traits, they are defining actors in the ecology, evolution, and epidemiology of parasitic species. To better understand this role, this chapter examines the relative importance of birds and parasites in natural communities, revisiting basic notions in community ecology. The impact of changes in diversity for disease dynamics, including the debate surrounding dilution and amplification effects are specifically addressed. By considering the intrinsic complexities of natural communities, the importance of combining data from host and parasite communities to better understand how natural systems function over time and space is highlighted. The different elements in each section of the chapter are illustrated with brief, concrete examples from avian species, with a detailed example from marine bird communities in which Lyme disease bacteria circulate.

Tropical rock coasts

2012 ◽  
Vol 37 (2) ◽  
pp. 206-226 ◽  
Author(s):  
Cherith A. Moses
Keyword(s):  
Climate Change ◽  
Temporal Variations ◽  
Future Research ◽  
Published Data ◽  
Time And Space ◽  
Erosion Rates ◽  
The Tropics ◽  
Over Time ◽  
Impacts Of Climate Change

Rock coasts are widespread in the tropics and exhibit particular morphologies that may be specific to their tropical, micro-tidal location. Notches are particularly well developed, often linked to onshore cliffs and fronted by subhorizontal platforms. Through a review of previously published data across the tropics, average cliff face erosion rates are calculated as 2.15 ± 2.62 mm a−1, intertidal erosion rates 3.03 ± 7.50 mm a−1 and subtidal erosion rates 0.96 ± 0.44 mm a−1. Intertidal erosion rates are variable within and across latitudinal ranges: within 10°N and S of the equator average rates are 1.42 ± 1.22 mm a−1; between latitudes of 10°and 20°, 0.88 ± 1.16 mm a−1 and between latitudes of 20°and 30°, 2.04 ± 2.57 mm a−1. A consideration of temporal variations in intertidal erosion rates provides insights into the potential impacts of climate change on the erosion dynamics of rock coasts in the tropics. This paper highlights some of the interactions over time and space between process and measurement that continue to limit our understanding of, and ability to model, the erosion dynamics of tropical rock coasts. It concludes by identifying potentially fruitful areas for future research.

scholarly journals Chronic exposure to neonicotinoids reduces honey bee health near corn crops

Science ◽  
2017 ◽  
Vol 356 (6345) ◽  
pp. 1395-1397 ◽  
Author(s):  
N. Tsvetkov ◽  
O. Samson-Robert ◽  
K. Sood ◽  
H. S. Patel ◽  
D. A. Malena ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Honey Bee ◽  
Honey Bees ◽  
Chronic Exposure ◽  
Social Immunity ◽  
Active Season ◽  
Bee Health ◽  
Honey Bee Health ◽  
Over Time

Experiments linking neonicotinoids and declining bee health have been criticized for not simulating realistic exposure. Here we quantified the duration and magnitude of neonicotinoid exposure in Canada’s corn-growing regions and used these data to design realistic experiments to investigate the effect of such insecticides on honey bees. Colonies near corn were naturally exposed to neonicotinoids for up to 4 months—the majority of the honey bee’s active season. Realistic experiments showed that neonicotinoids increased worker mortality and were associated with declines in social immunity and increased queenlessness over time. We also discovered that the acute toxicity of neonicotinoids to honey bees doubles in the presence of a commonly encountered fungicide. Our work demonstrates that field-realistic exposure to neonicotinoids can reduce honey bee health in corn-growing regions.

The evolution of business ethics in India

2014 ◽  
Vol 41 (11) ◽  
pp. 1073-1086 ◽  
Author(s):  
Ron Berger ◽  
Ram Herstein
Keyword(s):  
Business Ethics ◽  
Environmental Changes ◽  
Evolutionary Process ◽  
Business Culture ◽  
Conceptual Approach ◽  
Ethical Business ◽  
Holistic View ◽  
Content Type ◽  
Greco Roman ◽  
Over Time

Purpose – Religion and culture can influence ethical behavior in business. It is suggested that there has been and continues to be, a deep interrelationship between religion, business ethics, and economic activity in India. As India is becoming a major global economic business partner, understanding its unique ethical business infrastructure is gaining in importance. The purpose of this paper is to intend to further the understanding of Indian (“Vendantic”) business ethics, as opposed to Greco – Roman business ethics, as the foundation of business culture in India. This paper further elaborates on the evolution of business ethics and its implications on doing business in and with Indian companies. Design/methodology/approach – The authors undertook a conceptual approach in order to understand the evolutionary process of Indian business ethics in a holistic view in order to understand better its workings and effect on business interaction. Findings – The paper explains the constructs of business ethics in India and shows its evolution over time. Originality/value – This original theoretical paper examines the evolution of Indian business ethics over time in line with environmental changes in the Indian business landscape.

scholarly journals Spatially cascading effect of perturbations in experimental meta-ecosystems

2016 ◽  
Vol 283 (1838) ◽  
pp. 20161496 ◽  
Author(s):  
Eric Harvey ◽  
Isabelle Gounand ◽  
Pravin Ganesanandamoorthy ◽  
Florian Altermatt
Keyword(s):  
Population Dynamics ◽  
Community Dynamics ◽  
Local Community ◽  
Local Population ◽  
Temporal Variations ◽  
Landscape Scale ◽  
Cascading Effect ◽  
Regional Dynamics ◽  
The Relationship ◽  
Over Time

Ecosystems are linked to neighbouring ecosystems not only by dispersal, but also by the movement of subsidy. Such subsidy couplings between ecosystems have important landscape-scale implications because perturbations in one ecosystem may affect community structure and functioning in neighbouring ecosystems via increased/decreased subsidies. Here, we combine a general theoretical approach based on harvesting theory and a two-patch protist meta-ecosystem experiment to test the effect of regional perturbations on local community dynamics. We first characterized the relationship between the perturbation regime and local population demography on detritus production using a mathematical model. We then experimentally simulated a perturbation gradient affecting connected ecosystems simultaneously, thus altering cross-ecosystem subsidy exchanges. We demonstrate that the perturbation regime can interact with local population dynamics to trigger unexpected temporal variations in subsidy pulses from one ecosystem to another. High perturbation intensity initially led to the highest level of subsidy flows; however, the level of perturbation interacted with population dynamics to generate a crash in subsidy exchange over time. Both theoretical and experimental results show that a perturbation regime interacting with local community dynamics can induce a collapse in population levels for recipient ecosystems. These results call for integrative management of human-altered landscapes that takes into account regional dynamics of both species and resource flows.

Sign in / Sign up

Export Citation Format

Share Document