Life history, population genetics and feeding ecology of Caridina cantonensis and C. serrata(decapoda: Atyidae) in Hong Kong streams

In so far as it is associated with declining fertility and increasing mortality, senescence is directly detrimental to reproductive success. Natural selection should therefore act in the direction of postponing or eliminating senescence from the life history. The widespread occurrence of senescence is explained by observing that (i) the force of natural selection is generally weaker at late ages than at early ages, and (ii) the acquisition of greater longevity usually involves some cost. Two convergent theories are the ‘antagonistic pleiotropy’ theory, based in population genetics, and the ‘disposable soma’ theory, based in physiological ecology. The antagonistic pleiotropy theory proposes that certain alleles that are favoured because of beneficial early effects also have deleterious later effects. The disposable soma theory suggests that because of the competing demands of reproduction less effort is invested in the maintenance of somatic tissues than is necessary for indefinite survival.

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Highlights of Medical Entomology, 2020

Journal of Medical Entomology ◽

10.1093/jme/tjab103 ◽

2021 ◽

Author(s):

Chris M Stone

Keyword(s):

Population Genetics ◽

Life History ◽

Environmental Change ◽

Chemical Ecology ◽

Vector Surveillance ◽

Vector Ecology ◽

Medical Entomology ◽

Professional Activities ◽

And Control ◽

Incredible Year

Abstract Medical Entomology as a field is inherently global – thriving on international and interdisciplinary collaborations and affected dramatically by arthropod and pathogen invasions and introductions. This past year also will be remembered as the year in which the SARS-CoV-2 COVID-19 pandemic affected every part of our lives and professional activities and impacted (or changed, sometimes in good ways) our ability to collaborate and detect or respond to invasions. This incredible year is the backdrop for the 2020 Highlights in Medical Entomology. This article highlights the broad scope of approaches and disciplines represented in the 2020 published literature, ranging from sensory and chemical ecology, population genetics, impacts of human-mediated environmental change on vector ecology, life history and the evolution of vector behaviors, to the latest developments in vector surveillance and control.

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Outsourcing for How Long? Factors and Duration of Employing Foreign Live-in Domestic Helpers

Journal of Family Issues ◽

10.1177/0192513x211041982 ◽

2021 ◽

pp. 0192513X2110419

Author(s):

Adam K. L. Cheung

Keyword(s):

Life History ◽

Hong Kong ◽

Discrete Time ◽

Household Survey ◽

Domestic Labor ◽

Logit Models ◽

Cross Sectional ◽

History Data ◽

Life History Data ◽

Domestic Help

A remarkable rise in outsourcing domestic labor has been well documented, but the scope of the existing studies is limited. This study aims at investigating the factors and duration of using live-in domestic help in Hong Kong. The study also aims at disentangling the cross-sectional patterns in using paid domestic help into two different patterns: differential risks in the transition into the practice and the differential risks in the transition out from the practice. This study analyzes retrospective life-history data from a representative household survey ( N = 2003). Discrete-time logit models were employed. The results show that employing live-in helpers is a stable practice that could last for more than a decade. Yet, the factors for using and ending the practice are different. The results show that the flexible outsourcing framework could satisfactorily explain the families employing live-in helpers but is less applicable in explaining the duration of the practice.

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