Guiding lights: Foraging responses of juvenile nocturnal orb‐web spiders to the presence of artificial light at night

The reach of artificial light at night (ALAN) is growing rapidly around the globe, including the increasing use of energy‐efficient LED lights. Many studies document the physiological costs of light at night, but far fewer have focused on the potential benefits for nocturnal insectivores and the likely ecological consequences of shifts in predator–prey relationships. We investigated the effects of ALAN on the foraging behaviour and prey capture success in juvenile Australian garden orb‐web spiders (Eriophora biapicata). Laboratory experiments demonstrated that juvenile spiders were attracted to LED lights when choosing foraging sites, but prey availability was a stronger cue for remaining in a foraging site. Field experiments revealed a significant increase in prey capture rates for webs placed near LED lights. This suggests that any physiological costs of light at night may be offset by the foraging benefits, perhaps partially explaining recently observed increases in the size, fecundity and abundance of some orb‐web spider species in urban environments. Our results highlight the potential long‐term consequences of night lighting in urban ecosystems, through the impact of orb‐web spiders on insect populations.     

Circadian rhythms in screening pigment and invaginating organelles in photoreceptor terminals of the housefly's first optic neuropile

Screening pigment granules occur in the synaptic terminals of photoreceptors in the fly's (Musca domestica, L.) compound eye. The granules resemble ommochrome granules in the overlying photoreceptor cell body. There are also two types of invagination into receptor terminals: capitate projections (from glial cells) and invaginations from neighboring receptor terminals. The number of profiles of these organelles in the first optic neuropile, the lamina, have been counted using single-section quantitative electron microscopic methods. Pigment granules are concentrated proximally in the terminal, toward the brain. The numbers change, increasing during the night (1 h after lights off) up to values more than twice the number 1 h after lights on, apparently by longitudinal migration of granules from the cell body into the terminal. Flies entrained to day/night conditions and then held under constant darkness continue to exhibit changes in the numbers of profiles. Even though overall there were 80–90% fewer granule profiles than under day/night conditions, the numbers attained a peak many times higher at the end of the subjective day. Thus, the changes are endogenous, showing circadian rhythmicity. Although their significance is unknown, these changes parallel previously described circadian rhythms in the receptor terminals and their lamina monopolar-cell targets. The invaginations from receptor terminals were more numerous under day/night conditions than under constant darkness, and cycled in constant darkness, peaking at the end of subjective night. Capitate projections, by contrast, failed to change significantly under the experimental conditions analyzed, a lack of responsiveness they share with photoreceptor tetrad synapses. © 1997 John Wiley & Sons, Inc. J Neurobiol 32: 517–529, 1997     

Seasonal changes in the nocturnal singing routines of Common Nightingales Luscinia megarhynchos

Male Common Nightingales Luscinia megarhynchos famously sing at night. There are two distinct types of nocturnal singing routine (the dusk-to-dawn pattern of variation in song rate): (1) dusk and dawn choruses, with little or no song during the middle of the night; (2) a rapid increase in song rate after dusk, reaching a broad peak in the middle of the night, declining towards dawn, and followed by a dawn chorus. Males sing different nocturnal singing routines at different times in the breeding season. Earlier in the breeding season, most males sing Type 2 routines. Later in the breeding season, most males sing Type 1 routines, as do birds on the wintering grounds. At least some individuals may also sing Type 1 routines during the first few days after their arrival on their breeding territories, before the arrival of females. The main function of nocturnal song appears to be mate attraction. The patterns of variation in song rate over the course of the night are qualitatively similar to those predicted by stochastic dynamic programming (SDP) models of daily singing and foraging routines, for birds that do not forage at night, in circumstances when birds can pair at night (Type 2 routines), and when they cannot (Type 1 routines). The observed seasonal changes in the types of routine sung are also consistent with the predictions of these models.     

N-acetyltransferase activity, hydroxyindole-O-methyltransferase activity, and melatonin levels in the Harderian glands of the female Syrian hamster: changes during the light:dark cycle and the effect of 6-parachlorophenylalanine administration

The activities of NAT and HIOMT and the melatonin content of the Harderian glands of female Syrian hamsters were studied. When hamsters were kept under a light:dark cycle of 14:10 (lights on at 06.00 h), NAT activity exhibited a sharp, short term rise at one hour after lights on. Simultaneously, the activity of HIOMT, which forms melatonin, exhibited a rapid decline. Melatonin levels, like HIOMT activity, also showed a precipitous drop at one hour after light onset. After the respective changes, both NAT and HIOMT activity reverted back to night time levels. Melatonin levels remained depressed for several hours but by 1400 h (8 hours after lights on), nighttime melatonin values were re-established. Treatment of female hamsters with PCPA, a trytophan hydroxylase inhibitor, led to depressed levels of Harderian melatonin without affecting the activities of either NAT or HIOMT.     

The Switch from Low-Pressure Sodium to Light Emitting Diodes Does Not Affect Bat Activity at Street Lights

We used a before-after-control-impact paired design to examine the effects of a switch from low-pressure sodium (LPS) to light emitting diode (LED) street lights on bat activity at twelve sites across southern England. LED lights produce broad spectrum ‘white’ light compared to LPS street lights that emit narrow spectrum, orange light. These spectral differences could influence the abundance of insects at street lights and thereby the activity of the bats that prey on them. Most of the bats flying around the LPS lights were aerial-hawking species, and the species composition of bats remained the same after the switch-over to LED. We found that the switch-over from LPS to LED street lights did not affect the activity (number of bat passes), or the proportion of passes containing feeding buzzes, of those bat species typically found in close proximity to street lights in suburban environments in Britain. This is encouraging from a conservation perspective as many existing street lights are being, or have been, switched to LED before the ecological consequences have been assessed. However, lighting of all spectra studied to date generally has a negative impact on several slow-flying bat species, and LED lights are rarely frequented by these ‘light-intolerant’ bat species.     

Masters of efficiency

Manufacturing jobs may be shifting from the large drug companies to contract organizations as firms re-evaluate their strengths. But scientists with analytical skills and an eye for efficiency can find a job transforming materials into medicines.     

Tonoplast targeting of VHA‐a3 relies on a Rab5‐mediated but Rab7‐independent vacuolar trafficking route

Vacuolar trafficking routes and their regulators have recently drawn lots of attention in plant cell biology.A recent study reported the discovery of a plant-specific vacuolar trafficking route,i.e.,a direct ERto-vacuole route,through analysis of VHA-a3 subcellular targeting,a key component for the tonoplast VATPases.Our recent findings showed that VHA-a3 targets to the tonoplast through a Rab5-mediated but Rab7-independent pathway,shedding new lights on the unconventional vacuolar trafficking route in plant cells.     

The impacts of new street light technologies: experimentally testing the effects on bats of changing from low-pressure sodium to white metal halide

Artificial light at night is a major feature of anthropogenic global change and is increasingly recognized as affecting biodiversity, often negatively. On a global scale, newer technology white lights are replacing orange sodium lights to reduce energy waste. In 2009, Cornwall County Council (UK) commenced replacement of existing low-pressure sodium (LPS) high intensity discharge (HID) street lights with new Phillips CosmoPolis white ceramic metal halide street lights to reduce energy wastage. This changeover provided a unique collaborative opportunity to implement a before-after-control-impact field experiment to investigate the ecological effects of newly installed broad spectrum light technologies. Activity of the bat species Pipistrellus pipistrellus, P. pygmaeus and Nyctalus/Eptesicus spp. was significantly higher at metal halide than LPS lights, as found in other studies of bat activity at old technology (i.e. mercury vapour) white light types. No significant difference was found in feeding attempts per bat pass between light types, though more passes overall were recorded at metal halide lights. Species-specific attraction of bats to the metal halide lights could have cascading effects at lower trophic levels. We highlight the need for further research on possible ecosystem-level effects of light technologies before they are installed on a wide scale.     

Assessment of a new dynamic light regimen in a nuclear power control room without windows on quickly rotating shiftworkers--effects on health, wakefulness, and circadian alignment: a pilot study

The aim of the study was to test whether a new dynamic light regime would improve alertness, sleep, and adaptation to rotating shiftwork. The illumination level in a control room without windows at a nuclear power station was ~200 lux (straight-forward horizontal gaze) using a weak yellow light of 200 lux, 3000 K (Philips Master TLD 36 W 830). New lighting equipment was installed in one area of the control room above the positions of the reactor operators. The new lights were shielded from the control group by a distance of >6 m, and the other operators worked at desks turned away from the new light. The new lights were designed to give three different light exposures: (i) white/blue strong light of 745 lux, 6000 K; (ii) weak yellow light of 650 lux, 4000 K; and (iii) yellow moderate light of 700 lux, 4000 K. In a crossover design, the normal and new light exposures were given during a sequence of three night shifts, two free days, two morning shifts, and one afternoon shift (NNN?+?MMA), with 7 wks between sessions. The operators consisted of two groups; seven reactor operators from seven work teams were at one time exposed to the new equipment and 16 other operators were used as controls. The study was conducted during winter with reduced opportunities of daylight exposure during work, after night work, or before morning work. Operators wore actigraphs, filled in a sleep/wake diary, including ratings of sleepiness on the Karolinska Sleepiness Scale (KSS) every 2 h, and provided saliva samples for analysis of melatonin at work (every 2nd h during one night shift and first 3 h during one morning shift). Results from the wake/sleep diary showed the new light treatment increased alertness during the 2nd night shift (interaction group × light × time, p < .01). Time of waking was delayed in the light condition after the 3rd night shift (group × light, p < .05), but the amount of wake time during the sleep span increased after the 2nd night shift (p < .05), also showing a tendency to affect sleep efficiency (p < .10). Effects on circadian phase were difficult to establish given the small sample size and infrequent sampling of saliva melatonin. Nonetheless, it seems that appropriate dynamic light in rooms without windows during the dark Nordic season may promote alertness, sleep, and better adaptation to quickly rotating shiftwork.     

Stress-induced hyperthermia depends on both time of day and light condition

Rats placed in an environment other than their home cage increase their body temperature (Tb) by more than 1 degree C. This stress-induced hyperthermia is considered to be a fever, in the sense that the Tb rise seems to reflect an upward shift in the level of regulated Tb (set point). The circadian rhythm of Tb also reflects changes in set point. One might therefore expect to see differences in response to such stress during various phases of the light-dark (LD) cycle as Tb fluctuates between L and D. To test this, 3- to 6-month-old male Long-Evans rats were taken from their home cages (12:12 LD) and placed individually in a Plexiglas container for 30 min. Tb and activity were measured via telemetry. In the first experiment, rats were placed in the container during day (from 1 to 3 h after lights on) and night (from 1 to 3 h after lights off), with light on or off during the test. There was a significant Tb rise in response to placement in the container at all times except when the rats were tested during the night with light on in the container; in that condition there was no Tb rise. In the second experiment, the authors determined that 30 min of light in the home cage before the test did not affect Tb: If the light was on in the test situation, hyperthermia was inhibited, and if it was off, hyperthermia was as high as control levels. In the third experiment, to determine whether this effect was time dependent, the test was performed at 4-h intervals, with light on or off during the test. The strongest inhibiting effect of light was in early night. In the fourth experiment, the authors turned the lights on during early night while the rats were in their home cages. This reduced their Tb significantly by less than 0.3 degrees C. The authors conclude that both clock time and light condition during testing are factors affecting the Tb rise in response to stress.     

Day/night food consumption in mice is strain and age-dependent

Food consumption was measured during the day (lights on) and the night (lights off) and compared between one outbred and 9 inbred strains of mice (CBA/Kw, C3H, DBA2, KP, BALB/c, C57BL, B10.Amst, B10.BR, B10.BR Y-del) in age groups 30-60, 60-90, 90-120, and more than 120 days. Outbred mice and animals from B10 sublines ate significantly more during nocturnal darkness. Day and night food consumption was similar in KP animals. In mice from the remaining strains there was an apparent age-related shift from nocturnal towards diurnal eating habits.     

Axonal transport and neuronal transcytosis of trophic factors, tracers, and pathogens

Neurons can specifically internalize macromolecules, such as trophic factors, lectins, toxins, and other pathogens. Upon internalization in terminals, proteins can move retrogradely along axons, or, upon internalization at somatodendritic domains, they can move into an anterograde axonal transport pathway. Release of internalized proteins from neurons after either retrograde or anterograde axonal transport results in transcytosis and trafficking of proteins across multiple synapses. Recent studies of binding properties of several such proteins suggest that pathogens and lectins may utilize existing transport machineries designed for trafficking of trophic factors. Specific pathways may protect trophic factors, pathogens, and toxins from degradation after internalization and may target the trophic or pathogenic cargo for transcytosis after either retrograde or anterograde transport along axons. Elucidating the molecular mechanisms of sorting steps and transport pathways will further our understanding of trophic signaling and could be relevant for an understanding and possible treatment of neurological diseases such as rabies, Alzheimer's disease, and prion encephalopathies. At present, our knowledge is remarkably sparse about the types of receptors used by pathogens for trafficking, the signals that sort trophins or pathogens into recycling or degradation pathways, and the mechanisms that regulate their release from somatodendritic domains or axon terminals. This review intends to draw attention to potential convergences and parallels in trafficking of trophic and pathogenic proteins. It discusses axonal transport/trafficking mechanisms that may help to understand and eventually treat neurological diseases by targeted drug delivery.     

Illegal wildlife trade in the Himalayan region of China

The Himalayan region of China, with its rich biodiversity, used to be important for hunting and collecting of medicinal plants. In the past decades, conservation attitudes and legislation for wildlife conservation have developed rapidly in China. Increasing numbers of species are listed in the state protection list and local protection lists. In the Himalayan region, the area of natural reserves is high accounting for 70% of total area of natural reserves in China. However, wildlife in Himalayan region is suffering from illegal hunting and trade even after China has enforced the China Wildlife Protection Law (CWPL). The illegal wildlife trade and smuggling across Sino-neighbouring country borders and illegal wildlife trade related to domestic use flourish in the region. Although domestic illegal trade has declined in the past ten years, international illegal trade and smuggling continue, and are even expanding, thereby threatening survival of many endangered species such as the Tibetan antelope (Pantholops hodgsoni), Giant panda (Ailuropoda melanoleuca) and Saker Falcon (Falco cherrug). Illegal wildlife trade in the region is attributed to four factors. First, the CWPL is still imperfect, especially concerning illegal trade and smuggling across borders. Second, CWPL is not fully enforced. Third, infrastructure in many nature reserves is undeveloped and human resources are lacking. Fourth, protection is hampered by differences in the laws of neighbouring countries, differences in penalties and in degrees of protection. Furthermore, national legislation is often not fully enforced in areas that are inhabited mainly by tribal and minority communities.     

舟山眼镜蛇对光暗周期加热光源反应所导致的体温变化

用 7条舟山眼镜蛇 (Najaatra)研究动物对光暗周期加热光源反应所导致的体温变化。设计两项实验 ,每项实验历时 9d。实验一光照期覆盖整个白天 ,实验二光照期覆盖整个晚上。眼镜蛇仅在加热光源开启期间进行体温调节 ,但光照期内任何阶段都未发现所有个体同时处于热活动状态。两项实验中热活动个体百分比的时间变化显著 ,实验二热活动个体百分比波动相对大于实验一。在加热光源开启期间 ,实验一热活动眼镜蛇的百分比总体上大于实验二。在两项实验中 ,热活动眼镜蛇体温的时间变化都不显著。实验一热活动眼镜蛇的体温高于实验二 ,而两项实验中不处于热活动状态的眼镜蛇的平均体温无显著差异。实验一热活动眼镜蛇 (31 1±0 8°C)选择的体温上限高于实验二眼镜蛇 (2 6 0± 0 9°C)。在两项实验的任何时间段内 ,眼镜蛇的体温都不低于环境温度。     

Differential response of pineal melatonin levels to light at night in laboratory-raised and wild-captured 13-lined ground squirrels (Spermophilus Tridecemlineatus)

Pineal melatonin levels were compared in laboratory-raised or wild-captured 13-lined ground squirrels (Spermophilus tridecemlineatus) that were either exposed to 10 h of darkness at night or to light which had an irradiance of 400 μW/cm². In laboratory-born squirrels the period of darkness was associated with a gradual rise in pineal melatonin levels with peak values being reached at 0200 h, 6 h after darkness onset. Thereafter, melatonin levels decreased and were back to low daytime levels by 0800 h, 2 h after light onset. The exposure of laboratory-raised animals to an irradiance of 400 μW/cm² during the night totally prevented the nocturnal rise in pineal melatonin levels in these animals. In wild-captured ground squirrels the period of darkness at night was associated with a rapid rise in pineal melatonin such that by 2200 h, 2 h after lights out, peak melatonin values were already attained; additionally, melatonin levels remained high throughout the period of darkness but returned to daytime values by 0800 h. Exposure of wild-captured squirrels to a light irradiance of 400 μW/cm² during the normal dark period was completely incapable of suppressing pineal melatonin levels. The difference in the sensitivity of the pineal gland of laboratory-raised and wild-captured ground squirrels may relate to their previous lighting history.     

Transmigration of macrophages across the choroid plexus epithelium in response to the feline immunodeficiency virus

Although lentiviruses such as human, feline and simian immunodeficiency viruses (HIV, FIV, SIV) rapidly gain access to cerebrospinal fluid (CSF), the mechanisms that control this entry are not well understood. One possibility is that the virus may be carried into the brain by immune cells that traffic across the blood–CSF barrier in the choroid plexus. Since few studies have directly examined macrophage trafficking across the blood–CSF barrier, we established transwell and explant cultures of feline choroid plexus epithelium and measured trafficking in the presence or absence of FIV. Macrophages in co-culture with the epithelium showed significant proliferation and robust trafficking that was dependent on the presence of epithelium. Macrophage migration to the apical surface of the epithelium was particularly robust in the choroid plexus explants where 3-fold increases were seen over the first 24 h. Addition of FIV to the cultures greatly increased the number of surface macrophages without influencing replication. The epithelium in the transwell cultures was also permissive to PBMC trafficking, which increased from 17 to 26% of total cells after exposure to FIV. Thus, the choroid plexus epithelium supports trafficking of both macrophages and PBMCs. FIV significantly enhanced translocation of macrophages and T cells indicating that the choroid plexus epithelium is likely to be an active site of immune cell trafficking in response to infection.     

Abundance patterns of cubozoans on and near the Great Barrier Reef

The ecology of cubozoans is poorly understood and there are few quantitative studies on their distribution patterns. Sampling was designed to test first for variation in abundance with distance across the continental shelf in waters of the Great Barrier Reef, Australia. Second, we tested for the possible influence of islands versus submerged reefs on the abundances of cubozoan jellyfishes. Jellyfishes were collected after attraction to tethered night lights. Additional sampling focused on turbid near-shore waters. Carybdeid jellyfishes were found at mainland, inner, and mid-shelf reefs during summers between 2007 and 2010. No cubozoan medusae were found at outer reef sites. Copula sivickisi and Carukia barnesi were more abundant near reefs with islands than at fully submerged reefs. There was no evidence of lunar periodicity in abundance for these cubozoan taxa. Chironex fleckeri medusae were only found close to shore near the mainland, but they were rarely observed when riverine runoff was high. All taxa were characterized by high spatial and temporal variation and there was some evidence for small populations at spatial scales of less than one kilometer. “Blooms” and related intensity of predation and risk to humans are most likely at small spatial scales.     

Responses of insectivorous bats and nocturnal insects to local changes in street light technology

Artificial light at night is a pervasive anthropogenic stressor for biodiversity. Many fast‐flying insectivorous bat species feed on insects that are attracted to light‐emitting ultraviolet radiation (10–400 nm). Several countries are currently focused on replacing mercury vapour lamps, which emit ultraviolet light, with more cost‐efficient light‐emitting diode (LED) lights, which emit less ultraviolet radiation. This reduction in ultraviolet light may cause declines in insect densities in cities, predatory fast‐flying bats, and some edge‐foraging and slow‐flying bats. Capitalising on a scheme to update streetlights from high ultraviolet mercury vapour to low ultraviolet LED in Sydney, Australia, we measured the activity of individual bat species, the activity of different functional groups and the bat and insect communities, before and after the change in technology. We also surveyed sites with already LED lights, sites with mercury vapour lights and unlit bushland remnants. Species adapted to foraging in cluttered vegetation, and some edge‐space foraging species, were more active in unlit bushland sites than in all lit sites and decreased in activity at lit sites after the change to LED lights. The change to LED streetlights caused a decrease in the fast‐flying Chalinolobus gouldii but not Miniopterus schreibersii oceanensis, the latter being more influenced by seasonal and environmental variables. Insect biomass was not affected by changing light types, but instead was negatively correlated with the moon's percentage illuminance. Changing streetlights to LEDs could result in a decline in some insectivorous bats in cities. This study confirms that unlit urban bushland remnants are important refuges for high bat diversity, particularly for more clutter‐adapted species and some edge‐space foraging species. Preventing light penetration into unlit bushland patches and corridors remains essential to protect the urban bat community.     

Effects of acute cold exposure at night on pineal N-acetyltransferase activity and melatonin content in white-footed mice, Peromyscus leucopus

1. Pineal N-acetyltransferase (NAT) activity in long-day white-footed mice (Peromyscus leucopus) exposed to cold soon after onset of darkness was depressed relative to controls, whereas mice exposed to cold later at night had slightly elevated enzyme activity. 2. NAT activity in short-day mice exposed to cold soon after lights off did not differ from controls. Pineal melatonin in these mice, however, did not rise, as it did in controls. 3. These results suggest that acute cold exposure may modulate NAT activity, which is controlled primarily by the L:D cycle.     

Unemployment and illegal drug use: concordant evidence from a prospective study and national trends.

Data from a previous study of 1036 young people in the Lothian region that indicated an association between unemployment and illegal drug use were examined in more depth to investigate the inter-relation between duration of unemployment and the use of illegal drugs, alcohol, and tobacco. After factors such as social class background and educational qualifications had been taken into account a weak but significant association was found between duration of unemployment and illegal drug use. No such association was found for alcohol or tobacco. Similar results were obtained from an analysis of national statistics related to unemployment and illegal drug use. Both sets of data thus indicate that illegal drug use is moderately associated with unemployment.