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Artificial light at night (ALAN) is spreading worldwide and thereby is increasingly interfering with natural dark-light cycles. Meanwhile, effects of very low intensities of light pollution on animals have rarely been investigated. We explored the effects of low intensity ALAN over seven months in eight experimental bank vole (Myodes glareolus) populations in large grassland enclosures over winter and early breeding season, using LED garden lamps. initial populations consisted of eight individuals (32 animals per hectare) in enclosures with or without ALAN. We found that bank voles under ALAN experienced changes in daily activity patterns and space use behavior, measured by automated radio telemetry. There were no differences in survival and body mass, measured with live trapping, and none in levels of fecal glucocorticoid metabolites. Voles in the ALAN treatment showed higher activity at night during half moon, and had larger day ranges during new moon. Thus, even low levels of light pollution as experienced in remote areas or by sky glow can lead to changes in animal behavior and could have consequences for species interactions. (C) 2018 Elsevier Ltd. All rights reserved.
Migration phenology determines niche use of East Asian buntings (Emberizidae) during stopover
(2018)
Stopover niche utilization of birds during migration has not gained much attention so far, since the majority of the studies focuses on breeding or wintering areas. However, stopover sites are crucial for migratory birds. They are often used by a multitude of species, which could lead to increased competition. In this work, we investigated niche use of 8 migratory and closely related Emberiza bunting species at a stopover site in Far East Russia, situated on the poorly studied East Asian fly-way. We used bird ringing data to evaluate morphological similarity as well as niche overlap on the trophic, spatial, and temporal dimension. Bill morphology was used as a proxy for their trophic niche. We were able to prove that a majority of the species occupies well-defined stopover niches on at least one of the dimensions. Niche breadth and niche overlap differ between spring and autumn season with higher overlap found during spring. Morphological differences are mostly related to overall size and wing pointedness. The temporal dimension is most important for segregation among the studied species. Furthermore, all species seem to exhibit a rather strict and consistent phenological pattern. Their occurrence at the study site is highly correlated with their geographic origin and the length of their migration route. We assume that buntings are able to use available resources opportunistically during stopover, while trying to follow a precise schedule in order to avoid competition and to ensure individual fitness.
Off-grid
(2018)
1. Advances in LED technology combined with solar, storable energy bring light to places remote from electricity grids. Worldwide more than 1.3 billion of people are living off-grid, often in developing regions of high insect biodiversity. In developed countries, dark refuges for wildlife are threatened by ornamental garden lights. Solar powered LEDs (SPLEDs) are cheaply available, dim, and often used to illuminate foot paths, but little is known on their effects on ground living (epigeal) arthropods.
2. We used off-the-shelf garden lamps with a single ‘white’ LED (colour temperature 7250 K) to experimentally investigate effects on attraction and nocturnal activity of ground beetles (Carabidae).
3. We found two disparate and species-specific effects of SPLEDs. (i) Some nocturnal, phototactic species were not reducing activity under illumination and were strongly attracted to lamps (>20-fold increase in captures compared to dark controls). Such species aggregate in lit areas and SPLEDs may become ecological traps, while the species is drawn from nearby, unlit assemblages. (ii) Other nocturnal species were reducing mobility and activity under illumination without being attracted to light, which may cause fitness reduction in lit areas.
4. Both reactions offer mechanistic explanations on how outdoor illumination can change population densities of specific predatory arthropods, which may have cascading effects on epigeal arthropod assemblages. The technology may thus increase the area of artificial light at night (ALAN) impacting insect biodiversity.
5. Measures are needed to mitigate effects, such as adjustment of light colour temperature and automated switch-offs.
The complete mitochondrial genome of the common vole, Microtus arvalis (Rodentia: Arvicolinae)
(2018)
The common vole, Microtus arvalis belongs to the genus Microtus in the subfamily Arvicolinae. In this study, the complete mitochondrial genome of M. arvalis was recovered using shotgun sequencing and an iterative mapping approach using three related species. Phylogenetic analyses using the sequence of 21 arvicoline species place the common vole as a sister species to the East European vole (Microtus levis), but as opposed to previous results we find no support for the recognition of the genus Neodon within the subfamily Arvicolinae, as this is, as well as the genus Lasiopodomys, found within the Microtus genus.
The fast and the flexible
(2018)
The killing of young by unrelated males is widespread in the animal kingdom. In short-lived small rodents, females can mate immediately after delivery (post-partum oestrus) and invest in future reproduction, but infanticide may put the nestlings, their current reproductive investment, at risk. Here, we investigated the behavioural trade-offs between mating interest and nest protection in an arena experiment with bank voles (Myodes glareolus). Non-gravid females (n=33) were housed at one end of a large structured arena with their nestlings. Different scents (cage bedding) were presented to each female in a replicated design. Three combinations of mating opportunities and male-female familiarity were simulated using different scent donors: mating opportunity with the sire of the nestlings with whom the female was familiar; mating opportunity with a male unrelated to the offspring and unfamiliar to the female, thus posing a higher risk to the offspring; and neither risk nor mating opportunity (clean control). Most females investigated male scents, regardless of familiarity, leaving their litter unprotected. During control treatment, females with larger litters spent less time at the scent area, indicating increasing nursing demands or better protection. Females with older litters visited scents more often, suggesting an increased interest in reproduction while they are non-gravid alongside the decreased risk of infanticide for older young. In the presence of unfamiliar scents, females spent more time protecting their nests, supporting the perceived association of unfamiliarity with infanticide risk. Thus, rodent females flexibly allocate time spent between searching for a mate and protecting their nest, which is modulated by their familiarity with a potential intruder.Significance statementInfanticide by conspecific males is an extreme form of sexual conflict and has large costs on females, abolishing their investment into current offspring. In an experimental approach, we exposed lactating female bank voles to different combinations of mating opportunity and familiarity to a (simulated) intruder: (1) the sire of the nestlings with whom the female was familiar and, therefore, potentially less risky in terms of infanticide; (2) a male which was unrelated and unfamiliar to the female and thus posed a higher risk to the offspring; or (3) as a control, cage bedding, which posed neither risk of infanticide nor a mating opportunity. We show that females flexibly allocated pup protection and mating interest based on their familiarity with the male, indicating that the unfamiliar males pose a threat to offspring, which is perceived by the females. Females further adjusted their behaviour to the size and/or age of their current litter, investing more time in male scents when offspring were older, thus balancing future and current investments into reproduction.
The pace-of-life syndrome (POLS) hypothesis posits that life-history characteristics, among individual differences in behavior, and physiological traits have coevolved in response to environmental conditions. This hypothesis has generated much research interest because it provides testable predictions concerning the association between the slow-fast life-history continuum and behavioral and physiological traits. Although humans are among the most well-studied species and similar concepts exist in the human literature, the POLS hypothesis has not yet been directly applied to humans. Therefore, we aimed to (i) test predicted relationships between life history, physiology, and behavior in a human population and (ii) better integrate the POLS hypothesis with other similar concepts. Using data of a representative sample of German adolescents, we extracted maturation status for girls (menarche, n = 791) and boys (voice break, n = 486), and a set of health-related risk-taking behaviors and cardiovascular parameters. Maturation status and health-related risk behavior as well as maturation status and cardiovascular physiology covaried in boys and girls. Fast maturing boys and girls had higher blood pressure and expressed more risk-taking behavior than same-aged slow maturing boys and girls, supporting general predictions of the POLS hypothesis. Only some physiological and behavioral traits were positively correlated, suggesting that behavioral and physiological traits might mediate life-history trade-offs differently. Moreover, some aspects of POLS were sex-specific. Overall, the POLS hypothesis shares many similarities with other conceptual frameworks from the human literature and these concepts should be united more thoroughly to stimulate the study of POLS in humans and other animals. Significance statement The pace-of-life syndrome (POLS) hypothesis suggests that life history, behavioral and physiological traits have coevolved in response to environmental conditions. Here, we tested this link in a representative sample of German adolescents, using data from a large health survey (the KIGGs study) containing information on individual age and state of maturity for girls and boys, and a set of health-related risk-taking behaviors and cardiovascular parameters. We found that fast maturing girls and boys had overall higher blood pressure and expressed more risk-taking behavior than same-aged slow maturing girls and boys. Only some behavioral and physiological traits were positively correlated, suggesting that behavioral and physiological traits might mediate life-history trade-offs differently and not necessarily form a syndrome. Our results demonstrate a general link between life history, physiological and behavioral traits in humans, while simultaneously highlighting a more complex and rich set of relationships, since not all relationships followed predictions by the POLS hypothesis.