The role of ancestral phenotypic plasticity in evolutionary diversification: population density effects in horned beetles

Many behaviors of insects are stimulated, modified, or modulated by hormones. The principal hormones involved are the same as the ones that control moulting, metamorphosis, and other aspects of development, principally ecdysone and juvenile hormone. In addition, a small handful of neurosecretory hormones are involved in the control of specific behaviors. Because behavior is a plastic trait, this chapter begins by outlining the biology and hormonal control of phenotypic plasticity in insects, and how the hormonal control of behavior fits in with other aspects of the control of phenotypic plasticity. The rest of the chapter is organized around the diversity of behaviors that are known to be controlled by or affected by hormones. These include eclosion and moulting behavior, the synthesis and release of pheromones, migration, parental care, dominance, reproductive behavior, and social behavior.

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Population Density or Populations Size. Which Factor Determines Urban Traffic Congestion?

Sustainability ◽

10.3390/su13084280 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4280

Author(s):

Yu Sang Chang ◽

Sung Jun Jo ◽

Yoo-Taek Lee ◽

Yoonji Lee

Keyword(s):

Population Density ◽

Population Size ◽

Traffic Congestion ◽

Critical Role ◽

Small Population ◽

High Density ◽

Urban Traffic ◽

Contradictory Result ◽

Low Density

A large number of articles have documented that as population density of cities increases, car use declines and public transit use rises. These articles had a significant impact of promoting high-density compact urban development to mitigate traffic congestion. Another approach followed by other researchers used the urban scaling model to indicate that traffic congestion increases as population size of cities increases, thus generating a possible contradictory result. Therefore, this study examines the role of both density and population size on traffic congestion in 164 global cities by the use of Stochastic Impacts by Regression on Population, Affluence and Technology model. We divide 164 cities into the two subgroups of 66 low density cities and 98 high density cities for analysis. The findings from the subgroups analysis indicated a clear-cut difference on the critical role of density in low-density cities and the exclusive role of population size in high-density cities. Furthermore, using threshold regression model, 164 cities are divided into the two regions of large and small population cities to determine population scale advantage of traffic congestion. Our findings highlight the importance of including analysis of subgroups based on density and/or population size in future studies of traffic congestion.

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Adaptation of CERES-Maize model for a better simulation of plant population density effects

Field Crops Research ◽

10.1016/j.fcr.2019.04.017 ◽

2019 ◽

Vol 238 ◽

pp. 27-34 ◽

Cited By ~ 2

Author(s):

R. Cazanga ◽

J.F. Ledent ◽

E. von Bennewitz

Keyword(s):

Population Density ◽

Plant Population ◽

Density Effects ◽

Plant Population Density

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Vertical Migration in Daphnia: The Role of Phenotypic Plasticity in the Migration Pattern for Competing Clones or Species

Oikos ◽

10.2307/3546553 ◽

1998 ◽

Vol 83 (1) ◽

pp. 129 ◽

Cited By ~ 7

Author(s):

H. Boriss ◽

W. Gabriel

Keyword(s):

Phenotypic Plasticity ◽

Vertical Migration ◽

Migration Pattern

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Effect of school reopening on SARS-CoV-2 incidence in a low-prevalence region: Prospective SARS-CoV-2 testing in healthcare workers with primary school-attending children versus without children living at home

Journal of Infection Prevention ◽

10.1177/17571774211012469 ◽

2021 ◽

pp. 175717742110124

Author(s):

Melvin Frie ◽

Lisa M Havinga ◽

Janneke Wiersema-Buist ◽

Charlotte G Veldman ◽

Marjan JT de Vries ◽

...

Keyword(s):

Cohort Study ◽

Population Density ◽

Severe Acute Respiratory Syndrome ◽

Primary School ◽

Primary Schools ◽

Healthcare Workers ◽

Regional Strategies ◽

Low Prevalence ◽

At Home

Coronavirus disease 2019 (COVID-19) often presents asymptomatically or milder in children compared to adults. The role of young children in the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) remains largely unknown. In the Netherlands, the first action of loosening the partial lockdown that had been implemented to reduce SARS-CoV-2 transmission was the reopening of primary schools on 1 May 2020. We subsequently conducted a prospective cohort study among healthcare workers (HCWs) with primary school-attending children versus HCWs without children living at home. We tested each HCW three times for SARS-CoV-2 from May 20 to June 15 2020 at 1-week intervals. In total, 832 nasopharyngeal swabs were taken from 283 HCWs with primary school-attending children living at home and 864 nasopharyngeal swabs from 285 HCWs without children living at home. All nasopharyngeal swabs tested negative for SARS-CoV-2. In our region with a low population density and low SARS-CoV-2 prevalence, reopening of primary schools did not lead to an increase in infections. The results of this study may serve as an example for the implementation of regional strategies to reduce SARS-CoV-2 transmission in countries with large variations in both population density and SARS-CoV-2 prevalence.

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