scholarly journals Urban warming and artificial light alter dormancy in the flesh fly

2021 ◽  
Vol 8 (7) ◽  
pp. 210866
Author(s):  
Ayumu Mukai ◽  
Koki Yamaguchi ◽  
Shin G. Goto

Seasonal changes in temperature and day length are distinct between rural and urban areas due to urban warming and the presence of artificial light at night. Many studies have focused on the impacts of these ubiquitous signatures on daily biological events, but empirical studies on their impacts on insect seasonality are limited. In the present study, we used the flesh fly Sarcophaga similis as a model insect to determine the impacts of urbanization on the incidence and timing of diapause (dormancy), not only in the laboratory but also in rural and urban conditions. In the laboratory, diapause entry was affected by night-time light levels as low as 0.01 lux. We placed fly cages on outdoor shelves in urban and rural areas to determine the timing of diapause entry; it was retarded by approximately four weeks in urban areas relative to that in rural areas. Moreover, almost all flies in the site facing an urban residential area failed to enter diapause, even by late autumn. Although an autumnal low temperature in the urban area would mitigate the negative effect of artificial light at night, strong light pollution seriously disrupts the flesh fly seasonal adaptation.

2018 ◽  
Author(s):  
Nikolas J Willmott ◽  
Jessica Henneken ◽  
Caitlin J Selleck ◽  
Therésa M Jones

The prevalence of artificial light at night (ALAN) is increasing rapidly around the world. The potential physiological costs of this night lighting are often evident in life history shifts. We investigated the effects of chronic night-time exposure to ecologically relevant levels of LED lighting on the life history traits of the nocturnal Australian garden orb-web spider (Eriophora biapicata). We reared spiders under a 12-hour day and either a 12-hour natural darkness (~0 lux) or a 12-hour dim light (~20 lux) night and assessed juvenile development, growth and mortality, and adult reproductive success and survival. We found that exposure to ALAN accelerated juvenile development, resulting in spiders progressing through fewer moults, and maturing earlier and at a smaller size. There was a significant increase in daily juvenile mortality for spiders reared under 20 lux, but the earlier maturation resulted in a comparable number of 0 lux and 20 lux spiders reaching maturity. Exposure to ALAN also considerably reduced the number of eggs produced by females, largely associated with ALAN-induced reductions in body size. Despite previous observations of increased fitness for some orb-weavers in urban areas and near night lighting, it appears that exposure to artificial night lighting may lead to considerable developmental costs. Future research will need to consider the detrimental effects of ALAN combined with foraging benefits when studying nocturnal insectivores that forage around artificial lights.


Author(s):  
Nikolas J Willmott ◽  
Jessica Henneken ◽  
Caitlin J Selleck ◽  
Therésa M Jones

The prevalence of artificial light at night (ALAN) is increasing rapidly around the world. The potential physiological costs of this night lighting are often evident in life history shifts. We investigated the effects of chronic night-time exposure to ecologically relevant levels of LED lighting on the life history traits of the nocturnal Australian garden orb-web spider (Eriophora biapicata). We reared spiders under a 12-hour day and either a 12-hour natural darkness (~0 lux) or a 12-hour dim light (~20 lux) night and assessed juvenile development, growth and mortality, and adult reproductive success and survival. We found that exposure to ALAN accelerated juvenile development, resulting in spiders progressing through fewer moults, and maturing earlier and at a smaller size. There was a significant increase in daily juvenile mortality for spiders reared under 20 lux, but the earlier maturation resulted in a comparable number of 0 lux and 20 lux spiders reaching maturity. Exposure to ALAN also considerably reduced the number of eggs produced by females, largely associated with ALAN-induced reductions in body size. Despite previous observations of increased fitness for some orb-weavers in urban areas and near night lighting, it appears that exposure to artificial night lighting may lead to considerable developmental costs. Future research will need to consider the detrimental effects of ALAN combined with foraging benefits when studying nocturnal insectivores that forage around artificial lights.


2015 ◽  
Vol 282 (1816) ◽  
pp. 20151745 ◽  
Author(s):  
Kylie A. Robert ◽  
John A. Lesku ◽  
Jesko Partecke ◽  
Brian Chambers

Change in day length is an important cue for reproductive activation in seasonally breeding animals to ensure that the timing of greatest maternal investment (e.g. lactation in mammals) coincides with favourable environmental conditions (e.g. peak productivity). However, artificial light at night has the potential to interfere with the perception of such natural cues. Following a 5-year study on two populations of wild marsupial mammals exposed to different night-time levels of anthropogenic light, we show that light pollution in urban environments masks seasonal changes in ambient light cues, suppressing melatonin levels and delaying births in the tammar wallaby. These results highlight a previously unappreciated relationship linking artificial light at night with induced changes in mammalian reproductive physiology, and the potential for larger-scale impacts at the population level.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5599 ◽  
Author(s):  
Nikolas J. Willmott ◽  
Jessica Henneken ◽  
Caitlin J. Selleck ◽  
Therésa M. Jones

The prevalence of artificial light at night (ALAN) is increasing rapidly around the world. The potential physiological costs of this night lighting are often evident in life history shifts. We investigated the effects of chronic night-time exposure to ecologically relevant levels of LED lighting on the life history traits of the nocturnal Australian garden orb-web spider (Eriophora biapicata). We reared spiders under a 12-h day and either a 12-h natural darkness (∼0 lux) or a 12-h dim light (∼20 lux) night and assessed juvenile development, growth and mortality, and adult reproductive success and survival. We found that exposure to ALAN accelerated juvenile development, resulting in spiders progressing through fewer moults, and maturing earlier and at a smaller size. There was a significant increase in daily juvenile mortality for spiders reared under 20 lux, but the earlier maturation resulted in a comparable number of 0 lux and 20 lux spiders reaching maturity. Exposure to ALAN also considerably reduced the number of eggs produced by females, and this was largely associated with ALAN-induced reductions in body size. Despite previous observations of increased fitness for some orb-web spiders in urban areas and near night lighting, it appears that exposure to artificial night lighting may lead to considerable developmental costs. Future research will need to consider the detrimental effects of ALAN combined with foraging benefits when studying nocturnal insectivores that forage around artificial lights.


2020 ◽  
Vol 57 (6) ◽  
pp. 1694-1699 ◽  
Author(s):  
Katie M Westby ◽  
Kim A Medley

Abstract As the planet becomes increasingly urbanized, it is imperative that we understand the ecological and evolutionary consequences of urbanization on species. One common attribute of urbanization that differs from rural areas is the prevalence of artificial light at night (ALAN). For many species, light is one of the most important and reliable environmental cues, largely governing the timing of daily and seasonal activity patterns. Recently, it has been shown that ALAN can alter behavioral, phenological, and physiological traits in diverse taxa. For temperate insects, diapause is an essential trait for winter survival and commences in response to declining daylight hours in the fall. Diapause is under strong selection pressure in the mosquito, Aedes albopictus (Skuse); local adaptation and rapid evolution has been observed along a latitudinal cline. It is unknown how ALAN affects this photosensitive trait or if local adaptation has occurred along an urbanization gradient. Using a common garden experiment, we experimentally demonstrated that simulated ALAN reduces diapause incidence in this species by as much as 40%. There was no difference, however, between urban and rural demes. We also calculated diapause incidence from wild demes in urban areas to determine whether wild populations exhibited lower than predicted incidence compared to estimates from total nocturnal darkness. In early fall, lower than predicted diapause incidence was recorded, but all demes reached nearly 100% diapause before terminating egg laying. It is possible that nocturnal resting behavior in vegetation limits the amount of ALAN exposure this species experiences potentially limiting local adaptation.


Author(s):  
Remus Runcan

According to Romania’s National Rural Development Programme, the socio-economic situation of the rural environment has a large number of weaknesses – among which low access to financial resources for small entrepreneurs and new business initiatives in rural areas and poorly developed entrepreneurial culture, characterized by a lack of basic managerial knowledge – but also a large number of opportunities – among which access of the rural population to lifelong learning and entrepreneurial skills development programmes and entrepreneurs’ access to financial instruments. The population in rural areas depends mainly on agricultural activities which give them subsistence living conditions. The gap between rural and urban areas is due to low income levels and employment rates, hence the need to obtain additional income for the population employed in subsistence and semi-subsistence farming, especially in the context of the depopulation trend. At the same time, the need to stimulate entrepreneurship in rural areas is high and is at a resonance with the need to increase the potential of rural communities from the perspective of landscape, culture, traditional activities and local resources. A solution could be to turn vegetal and / or animal farms into social farms – farms on which people with disabilities (but also adolescents and young people with anxiety, depression, self-harm, suicide, and alexithymia issues) might find a “foster” family, bed and meals in a natural, healthy environment, and share the farm’s activities with the farmer and the farmer’s family: “committing to a regular day / days and times for a mutually agreed period involves complying with any required health and safety practices (including use of protective clothing and equipment), engaging socially with the farm family members and other people working on and around the farm, and taking on tasks which would include working on the land, taking care of animals, or helping out with maintenance and other physical work”


BMJ Open ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. e042762
Author(s):  
Shuai Yuan ◽  
Shao-Hua Xie

ObjectiveThe substantial differences in socioeconomic and lifestyle exposures between urban and rural areas in China may lead to urban–rural disparity in cancer risk. This study aimed to assess the urban–rural disparity in cancer incidence in China.MethodsUsing data from 36 regional cancer registries in China in 2008–2012, we compared the age-standardised incidence rates of cancer by sex and anatomic site between rural and urban areas. We calculated the rate difference and rate ratio comparing rates in rural versus urban areas by sex and cancer type.ResultsThe incidence rate of all cancers in women was slightly lower in rural areas than in urban areas, but the total cancer rate in men was higher in rural areas than in urban areas. The incidence rates in women were higher in rural areas than in urban areas for cancers of the oesophagus, stomach, and liver and biliary passages, but lower for cancers of thyroid and breast. Men residing in rural areas had higher incidence rates for cancers of the oesophagus, stomach, and liver and biliary passages, but lower rates for prostate cancer, lip, oral cavity and pharynx cancer, and colorectal cancer.ConclusionsOur findings suggest substantial urban–rural disparity in cancer incidence in China, which varies across cancer types and the sexes. Cancer prevention strategies should be tailored for common cancers in rural and urban areas.


Author(s):  
Ruchika Agarwala ◽  
Vinod Vasudevan

Research shows that traffic fatality risk is generally higher in rural areas than in urban areas. In developing countries, vehicle ownership and investments in public transportation typically increase with economic growth. These two factors together increase the vehicle population, which in turn affects traffic safety. This paper presents a study focused on the relationship of various factors—including household consumption expenditure data—with traffic fatality in rural and urban areas and thereby aims to fill some of the gaps in the literature. One such gap is the impacts of personal and non-personal modes of travel on traffic safety in rural versus urban areas in developing countries which remains unexplored. An exhaustive panel data modeling approach is adopted. One important finding of this study is that evidence exists of a contrasting relationship between household expenditure and traffic fatality in rural and urban areas. The relationship between household expenditure and traffic fatality is observed to be positive in rural areas and a negative in urban areas. Increases in most expenditure variables, such as fuel, non-personal modes of travel, and two-wheeler expenditures, are found to be associated with an increase in traffic fatality in rural areas.


2017 ◽  
Vol 44 (6) ◽  
pp. 715-731 ◽  
Author(s):  
Ivy Drafor

Purpose The purpose of this paper is to analyse the spatial disparity between rural and urban areas in Ghana using the Ghana Living Standards Survey’s (GLSS) rounds 5 and 6 data to advance the assertion that an endowed rural sector is necessary to promote agricultural development in Ghana. This analysis helps us to know the factors that contribute to the depravity of the rural sectors to inform policy towards development targeting. Design/methodology/approach A multivariate principal component analysis (PCA) and hierarchical cluster analysis were applied to data from the GLSS-5 and GLSS-6 to determine the characteristics of the rural-urban divide in Ghana. Findings The findings reveal that the rural poor also spend 60.3 per cent of their income on food, while the urban dwellers spend 49 per cent, which is an indication of food production capacity. They have low access to information technology facilities, have larger household sizes and lower levels of education. Rural areas depend a lot on firewood for cooking and use solar/dry cell energies and kerosene for lighting which have implications for conserving the environment. Practical implications Developing the rural areas to strengthen agricultural growth and productivity is a necessary condition for eliminating spatial disparities and promoting overall economic development in Ghana. Addressing rural deprivation is important for conserving the environment due to its increased use of fuelwood for cooking. Absence of alternatives to the use of fuelwood weakens the efforts to reduce deforestation. Originality/value The application of PCA to show the factors that contribute to spatial inequality in Ghana using the GLSS-5 and GLSS-6 data is unique. The study provides insights into redefining the framework for national poverty reduction efforts.


2021 ◽  
Vol 48 (2) ◽  
pp. 441-456
Author(s):  
Ashikur Rahman Shome ◽  
Md Mahabub Alam ◽  
Md Fazle Rabbe ◽  
Mohammad Mijanur Rahman ◽  
Mohammad Firoj Jaman

A study on diversity, status, and habitat preference of avifauna was conducted from November 2017 to October 2018 in Magura Sadar upazila, Magura. Data was collected through direct field observations using line-transect method. Field surveys were made for three days per month in both rural and urban sites. A total of 140 species of birds belonged to 18 orders and 48 families were reported. Among the total species, 55% (77 species) were non-passerines and 45% (63 species) passerines with the highest individuals were counted under order Passeriformes. Resident bird species were dominant (106 species, 75.71%) over migratory (34 species, 24.28%) species. Species richness was the highest in the rural areas (124 species, 88.57%) and occurrence was the highest in winter season (97 species, 69.29%). The maximum species were recorded from trees (87 species, 62.14%) as preferred habitat. In this study, in total 4,060 individuals of birds were counted and among them, 51.55% (n=2093) were observed in the rural areas and 48.45% (n=1967) were in the urban areas. The highest number of birds was found in December (10.34%, n=432) and seasonal abundance was the highest in winter (40.15%, n=1630). Abundance was the highest for Common Myna (5.76%, n=234) among all recorded species. Diversity indices showed that the bird species were the most diverse in the rural areas in the winter season and in July. Habitat diversity indices were the highest for trees and birds used different types of habitats at different times for roosting, breeding and feeding. Regarding the observation status, 29.28% species was very common, 4.28% common, 31.42% fairly common, and 35% were few. This baseline data indicate that this study site is significant from the ecological and conservation point of views. Therefore, further research is necessary to understand how this avian diversity is maintained in this ecological setting. Bangladesh J. Zool. 48(2): 441-456, 2020


Sign in / Sign up

Export Citation Format

Share Document