Attraction of petrels to artificial lights in the Canary Islands: effects of the moon phase and age class

The extent and intensity of artificial night lighting has increased with urban development worldwide. The resulting light pollution is responsible for mortality among many Procellariiformes species which show nocturnal activity on their breeding grounds. Here, we report light‐induced mortality of Procellariiformes during a 9‐year study (1998–2006) on Tenerife, the largest island of the Canary archipelago. A total of 9880 birds from nine species were found grounded, the majority being Cory’s Shearwaters Calonectris diomedea (93.4%). For this species the majority of grounded birds were fledglings (96.4%), which fall apparently while leaving their nesting colony for the first time; for the smaller species (storm‐petrels) adult birds were more often grounded than fledglings. For almost all species, grounding showed a seasonal pattern linked with their breeding cycle. Certain phases of the moon influenced grounding of Cory’s Shearwater, with the extent of grounding being reduced during phases of full moon. The percentage of fledglings attracted to lights in relation to the fledglings produced annually varied between species and years (0–1.3% for the Madeiran Storm‐petrel Oceanodroma castro; 41–71% for Cory’s Shearwater). Mean adult mortality rates also varied between species (from 0.4% for the European Storm‐petrel Hydrobates pelagicus and the Cory’s Shearwater, to 2.3% for the Manx Shearwater Puffinus puffinus). Here we show that light‐induced mortality rates are of concern, at least for petrels and small shearwaters. Thanks to efforts involving civil cooperation, 95% of grounded birds have been returned to the wild. To minimize the impact of artificial lights on petrels we recommend several conservation measures: continuing rescue campaigns, alteration of light signatures and reduction of light emissions during the fledging peaks. Furthermore, we recommend that a monitoring program for petrel populations be implemented, as well as further studies to assess the fate of released fledglings and continued research to address why petrels are attracted to lights.     

Impacts of “supermoon” events on the physiology of a wild bird

The position of the Moon in relation to the Earth and the Sun gives rise to several predictable cycles, and natural changes in nighttime light intensity are known to cause alterations to physiological processes and behaviors in many animals. The limited research undertaken to date on the physiological responses of animals to the lunar illumination has exclusively focused on the synodic lunar cycle (full moon to full moon, or moon phase) but the moon's orbit—its distance from the Earth—may also be relevant. Every month, the moon moves from apogee, its most distant point from Earth—and then to perigee, its closest point to Earth. Here, we studied wild barnacle geese (Branta leucopsis) to investigate the influence of multiple interacting lunar cycles on the physiology of diurnally active animals. Our study, which uses biologging technology to continually monitor body temperature and heart rate for an entire annual cycle, asks whether there is evidence for a physiological response to natural cycles in lunar brightness in wild birds, particularly “supermoon” phenomena, where perigee coincides with a full moon. There was a three‐way interaction between lunar phase, lunar distance, and cloud cover as predictors of nighttime mean body temperature, such that body temperature was highest on clear nights when the full moon coincided with perigee moon. Our study is the first to report the physiological responses of wild birds to “supermoon” events; the wild geese responded to the combination of two independent lunar cycles, by significantly increasing their body temperature at night. That wild birds respond to natural fluctuations in nighttime ambient light levels support the documented responses of many species to anthropogenic sources of artificial light, that birds seem unable to override. As most biological systems are arguably organized foremost by light, this suggests that any interactions between lunar cycles and local weather conditions could have significant impacts on the energy budgets of birds.     

Celestial moderation of tropical seabird behavior

Most animals, including birds, have cyclic life histories and numerous studies generally conducted on captive animals have shown that photoperiod is the main factor influencing this periodicity. Moon cycles can also affect periodic behavior of birds. Few studies have investigated the influence of these environmental cues in natural settings, and particularly in tropical areas where the change in photoperiod is slight and some bird species keep cyclic behaviors. Using miniaturized light sensors, we simultaneously investigated under natural conditions the influence of photoperiod and moon phases on the migration dates and at-sea activity of a tropical seabird species, the Barau's petrel, throughout its annual cycle. Firstly, we found that birds consistently started their pre- and post-breeding migrations at precise dates corresponding in both cases to a day-duration of 12.5 hours, suggesting a strong influence of the photoperiod in the regulation of migration behavior. We also found that mean population arrival dates to the colony changed from year to year and they were influenced by moon phases. Returns at their colonies occurred around the last full moon of the austral winter, suggesting that moon cycle is used by birds to synchronize their arrival. Secondly, variations of day-time activity were sinusoidal and correlated to seasonal changes of daylength. We thus hypothesize that the photoperiod could directly affect the behavior of the birds at sea. Night-time at-sea activity exhibited a clear cycle of 29.2 days, suggesting that nocturnal foraging was highly regulated by moon phase, particularly during the non-breeding season. To our knowledge, this is the first study to document a mixed regulation of the behavior of a wild bird by photoperiod and moon phases throughout its annual cycle.     

Nest height is affected by lamppost lighting proximity in addition to nestbox size in urban great tits

Both natural and artificial light have proximate influences on many aspects of avian biology, physiology and behaviour. To date artificial light at night is mostly considered as being a nuisance disrupting for instance sleep and reproduction of diurnal species. Here, we investigate if lamppost night lighting affects cavity‐nesting bird species inside their breeding cavity. Nest height in secondary cavity‐nesting species is the result of trade‐offs between several selective forces. Predation is the prevailing force leading birds to build thin nests to increase the distance towards the entrance hole. A thin nest may also limit artificial light exposure at night. Yet, a minimum level of daylight inside nesting cavities is necessary for adequate visual communication and/or offspring development. Against this background, we hypothesised that avian nest‐building behaviour varies in response to a change in night lighting. We monitored nest height of urban great tits Parus major during six years and found that it varied with artificial light proximity. The birds built thinner nests inside nestboxes of various sizes in response to increasing lamppost night light availability at the nest. In large nestboxes, the nests were also thinner when a lamppost was present in the territory. Whether this relationship between artificial night lighting and nest height reflects a positive or negative effect of urbanisation is discussed in the light of recent experimental studies conducted in rural populations by other research groups.     

Remote sensing to map influence of light pollution on Cory’s shearwater in São Miguel Island,Azores Archipelago

Global economic and population growth increase the extent and intensity of artificial night lighting. From an ecological perspective, this is light pollution, which causes changes in reproductive physiology, migration and foraging of many species and ultimately leads to loss of biodiversity. Some seabirds are intimately linked with the light features of their environments because they are nocturnally active. We report light-induced groundings of Cory’s shearwater (Calonectris diomedea) during a 2-year study (2008 and 2009) in São Miguel Island, in the Azores archipelago, and investigate the spatial correlation of locations of grounded birds with an annual composite of remotely sensed stable lights. Results indicate that 16.7% of fledglings are attracted to lights. The exposure of shearwater colonies in the study area to artificial night lighting is low overall. Four colonies account for 87% of the grounded birds. The distance each bird was found from the closest colony was best explained by the ratio of the satellite-measured light levels at the grounding spot to the light levels at the assigned colony of origin. These results demonstrate that satellite-observed nighttime lights are sufficient to assess risk to marine birds at the scale of oceanic islands and indicate their utility for monitoring the effectiveness of programs to manage lighting to reduce risk for these species and conducting global assessments of species vulnerability. To minimize the impact on Cory’s shearwater and other marine birds, we recommend measures such as reduction and control of lighting intensity near colony locations, while continuing and re-enforcing rescue campaigns.     

Environmental factors determining the establishment of the African Long‐legged Buzzard Buteo rufinus cirtensis in Western Europe

Winters have become warmer under the impact of climate change, which has modified the phenology as well as the distribution ranges of birds. The African Long‐legged Buzzard Buteo rufinus cirtensis has recently colonized Europe via the Strait of Gibraltar. We aim to explain the native distribution of this species and to predict favourable areas in newly colonized parts of Europe using geospatial modelling to identify the most influential factors in this process. We applied the favourability function, a generalized linear model describing environmental favourability, for the presence/absence of breeding areas in northern Morocco and the southern Iberian Peninsula, according to a set of variables describing climate, topography, human activity, vegetation and purely spatial trends. A model was built using some known breeding sites in northern Morocco, and was used to forecast future suitable breeding areas in Europe. A second model was built with the available data for northern Morocco and Europe to explain the current distribution of breeding sites. Both models were assessed according to discrimination, calibration and parsimony criteria, and the influence of each factor was analysed using variation partitioning. We conclude that the Iberian Peninsula could provide new suitable areas for the species and facilitate its northward expansion. This result, together with the increasing number of records available, suggests that this species could soon spread throughout Europe. Steady temperatures and abundant but seasonally distributed precipitation showed the strongest predictive power in the models. This indicates a close relationship between the species’ distribution and climate in the study area, and suggests that this species finds its most favourable environments in the Mediterranean biome. Topography and vegetation, specifically cliffs and woods near hunting zones, point to a fine‐scale habitat selection for breeding. As the case of the African Long‐legged Buzzard is not a unique event, our results may be useful to determine whether a northward expansion of the Mediterranean biome could be followed by distribution shifts of bird species that have so far been restricted to Africa.     

Ancestral origins and invasion pathways in a globally invasive bird correlate with climate and influences from bird trade

Invasive species present a major threat to global biodiversity. Understanding genetic patterns and evolutionary processes that reinforce successful establishment is paramount for elucidating mechanisms underlying biological invasions. Among birds, the ring‐necked parakeet (Psittacula krameri) is one of the most successful invasive species, established in over 35 countries. However, little is known about the evolutionary genetic origins of this species and what population genetic signatures tell us about patterns of invasion. We reveal the ancestral origins of populations across the invasive range and explore the potential influence of climate and propagule pressure from the pet trade on observed genetic patterns. Ring‐necked parakeet samples representing the ancestral native range (n = 96) were collected from museum specimens, and modern samples from the invasive range (n = 855) were gathered from across Europe, Mauritius and Seychelles, and sequenced for two mitochondrial DNA markers comprising 868 bp of cytochrome b and control region, and genotyped at 10 microsatellite loci. Invasive populations comprise birds that originate predominantly from Pakistan and northern areas of India. Haplotypes associated with more northerly distribution limits in the ancestral native range were more prevalent in invasive populations in Europe, and the predominance of Asian haplotypes in Europe is consistent with the higher number of Asian birds transported by the pet trade outside the native range. Successful establishment of invasive species is likely to be underpinned by a combination of environmental and anthropogenic influences.     

Capturing American White Ibises in urban South Florida using two novel techniques

As many wildlife species, including wading birds, adapt to anthropogenic landscapes and, in some cases, exhibit altered behaviors, studies that involve capturing birds may require new methods better suited for use in urban areas and to accommodate altered animal behavior. We developed two novel techniques, a leg lasso and flip net, for capturing American White Ibises (Eudocimus albus) in urban environments in southern Florida, and also used a traditional technique (mist‐nets) in non‐urban wetland habitats. The flip net and leg lasso were developed to capture White Ibises habituated to the presence of humans. Ibises were captured in urban and wetland environments from October 2015 to August 2017 in Palm Beach, Broward, and Lee counties, Florida. We captured 6.0 ± 13.5 ibis/h with the flip net, 1.6 ± 0.8 ibis/h with the leg lasso, and 0.5 ± 2.6 ibis/h with mist‐nets. We captured larger (higher mass to tarsus length ratio) birds using the flip net and leg lasso than using mist‐nets, and captured more males with leg lassos than with other two techniques. The novel techniques we used are efficient, cost effective, easy to use, and also potentially useful for capturing other species of birds. Leg lassos and flip nets are also safe to use in populated areas for both birds and humans.     

NIGHT COUNTS OF HARES AND OTHER ANIMALS IN EAST AFRICA

Night counts of hares and other animals were made on a disused airstrip in the Queen Elizabeth National Park, Uganda and on the road between Magadi and Nairobi in Kenya. Lepus crawshayi is the only species of hare which occurs in the Queen Elizabeth Park but L. capensis is also found in Kenya. No regular seasonal fluctuations were found in the number of hares recorded due probably to the continuous breeding of these equatorial species. The number of waterbuck seen in Uganda on moonlit nights was significantly greater than that counted on dark nights. This is not thought to be due to better viewing conditions under a full moon since the phenomenon was not found with other species. The number of hares recorded varied inversely with the number of other mammals present but bore no relationship with the number of birds. It is concluded that night counts can be useful in revealing population trends but not for assessing total numbers or for comparing densities in different areas.     

Polymorphism at the Clock gene predicts phenology of long‐distance migration in birds

Dissecting phenotypic variance in life history traits into its genetic and environmental components is at the focus of evolutionary studies and of pivotal importance to identify the mechanisms and predict the consequences of human‐driven environmental change. The timing of recurrent life history events (phenology) is under strong selection, but the study of the genes that control potential environmental canalization in phenological traits is at its infancy. Candidate genes for circadian behaviour entrained by photoperiod have been screened as potential controllers of phenological variation of breeding and moult in birds, with inconsistent results. Despite photoperiodic control of migration is well established, no study has reported on migration phenology in relation to polymorphism at candidate genes in birds. We analysed variation in spring migration dates within four trans‐Saharan migratory species (Luscinia megarhynchos; Ficedula hypoleuca; Anthus trivialis; Saxicola rubetra) at a Mediterranean island in relation to Clock and Adcyap1 polymorphism. Individuals with larger number of glutamine residues in the poly‐Q region of Clock gene migrated significantly later in one or, respectively, two species depending on sex and whether the within‐individual mean length or the length of the longer Clock allele was considered. The results hinted at dominance of the longer Clock allele. No significant evidence for migration date to covary with Adcyap1 polymorphism emerged. This is the first evidence that migration phenology is associated with Clock in birds. This finding is important for evolutionary studies of migration and sheds light on the mechanisms that drive bird phenological changes and population trends in response to climate change.     

Beyond the landscape: Resistance modelling infers physical and behavioural gene flow barriers to a mobile carnivore across a metropolitan area

Urbanization affects key aspects of wildlife ecology. Dispersal in urban wildlife species may be impacted by geographical barriers but also by a species’ inherent behavioural variability. There are no functional connectivity analyses using continuous individual‐based sampling across an urban‐rural continuum that would allow a thorough assessment of the relative importance of physical and behavioural dispersal barriers. We used 16 microsatellite loci to genotype 374 red foxes (Vulpes vulpes) from the city of Berlin and surrounding rural regions in Brandenburg in order to study genetic structure and dispersal behaviour of a mobile carnivore across the urban‐rural landscape. We assessed functional connectivity by applying an individual‐based landscape genetic optimization procedure. Three commonly used genetic distance measures yielded different model selection results, with only the results of an eigenvector‐based multivariate analysis reasonably explaining genetic differentiation patterns. Genetic clustering methods and landscape resistance modelling supported the presence of an urban population with reduced dispersal across the city border. Artificial structures (railways, motorways) served as main dispersal corridors within the cityscape, yet urban foxes avoided densely built‐up areas. We show that despite their ubiquitous presence in urban areas, their mobility and behavioural plasticity, foxes were affected in their dispersal by anthropogenic presence. Distinguishing between man‐made structures and sites of human activity, rather than between natural and artificial structures, is thus essential for better understanding urban fox dispersal. This differentiation may also help to understand dispersal of other urban wildlife and to predict how behaviour can shape population genetic structure beyond physical barriers.     

Fatal Attraction of Short-Tailed Shearwaters to Artificial Lights

Light pollution is increasing around the world and altering natural nightscapes with potential ecological and evolutionary consequences. A severe ecological perturbation caused by artificial lights is mass mortalities of organisms, including seabird fledglings that are attracted to lights at night on their first flights to the sea. Here, we report on the number of fledging short-tailed shearwaters Ardenna tenuirostris found grounded in evening and morning rescue patrols conducted at Phillip Island, Australia, during a 15-year period (1999–2013). We assessed factors affecting numbers of grounded birds and mortality including date, moon phase, wind direction and speed, number of visitors and holiday periods. We also tested experimentally if birds were attracted to lights by turning the lights off on a section of the road. Of 8871 fledglings found, 39% were dead or dying. This mortality rate was 4–8 times higher than reported elsewhere for other shearwater species, probably because searching for fledglings was part of our systematic rescue effort rather than the opportunistic rescue used elsewhere. Thus, it suggests that light-induced mortality of seabirds is usually underestimated. We rescued more birds (dead and alive) in peak fledging, moonless and windy nights. Mortality increased through the fledging period, in the mornings and with increased traffic on holiday periods. Turning the road lights off decreased the number of grounded birds (dead and alive). While moon, wind and time are uncontrolled natural constraints, we demonstrated that reduction of light pollution and better traffic management can mitigate artificial light-induced mortality.     

Robust geographical determinants of infection prevalence and a contrasting latitudinal diversity gradient for haemosporidian parasites in Western Palearctic birds

Identifying robust environmental predictors of infection probability is central to forecasting and mitigating the ongoing impacts of climate change on vector‐borne disease threats. We applied phylogenetic hierarchical models to a data set of 2,171 Western Palearctic individual birds from 47 species to determine how climate and landscape variation influence infection probability for three genera of haemosporidian blood parasites (Haemoproteus, Leucocytozoon, and Plasmodium). Our comparative models found compelling evidence that birds in areas with higher vegetation density (captured by the normalized difference vegetation index [NDVI]) had higher likelihoods of carrying parasite infection. Magnitudes of this relationship were remarkably similar across parasite genera considering that these parasites use different arthropod vectors and are widely presumed to be epidemiologically distinct. However, we also uncovered key differences among genera that highlighted complexities in their climate responses. In particular, prevalences of Haemoproteus and Plasmodium showed strong but contrasting relationships with winter temperatures, supporting mounting evidence that winter warming is a key environmental filter impacting the dynamics of host‐parasite interactions. Parasite phylogenetic community diversities demonstrated a clear but contrasting latitudinal gradient, with Haemoproteus diversity increasing towards the equator and Leucocytozoon diversity increasing towards the poles. Haemoproteus diversity also increased in regions with higher vegetation density, supporting our evidence that summer vegetation density is important for structuring the distributions of these parasites. Ongoing variation in winter temperatures and vegetation characteristics will probably have far‐reaching consequences for the transmission and spread of vector‐borne diseases.     

The potential for dispersal of microalgal resting cysts by migratory birds

Most microalgal species are geographically widespread, but little is known about how they are dispersed. One potential mechanism for long‐distance dispersal is through birds, which may transport cells internally (endozoochory) and deposit them during, or in‐between, their migratory stopovers. We hypothesize that dinoflagellates, in particular resting stages, can tolerate bird digestion; that bird temperature, acidity, and retention time negatively affect dinoflagellate viability; and that recovered cysts can germinate after passage through the birds’ gut, contributing to species‐specific dispersal of the dinoflagellates across scales. Tolerance of two dinoflagellate species (Peridiniopsis borgei, a warm‐water species and Apocalathium malmogiense, a cold‐water species) to Mallard gut passage was investigated using in vitro experiments simulating the gizzard and caeca conditions. The effect of in vitro digestion and retention time on cell integrity, cell viability, and germination capacity of the dinoflagellate species was examined targeting both their vegetative and resting stages. Resting stages (cysts) of both species were able to survive simulated bird gut passage, even if their survival rate and germination were negatively affected by exposure to acidic condition and bird internal temperature. Cysts of A. malmogiense were more sensitive than P. borgei to treatments and to the presence of digestive enzymes. Vegetative cells did not survive conditions of bird internal temperature and formed pellicle cysts when exposed to gizzard‐like acid conditions. We show that dinoflagellate resting cysts serve as dispersal propagules through migratory birds. Assuming a retention time of viable cysts of 2–12 h to duck stomach conditions, cysts could be dispersed 150–800 km and beyond.     

Contrasting patterns of amphipod dispersion in a seagrass meadow between day and night: consistency through a lunar cycle

Changes in light intensity, typically over the course of a day, affect the dispersion of aquatic organisms at short temporal scales. Amphipods, for example, have strong behavioural responses to light conditions. In this study, we used amphipod assemblages inhabiting a Cymodocea nodosa seagrass meadow on the east coast of Gran Canaria Island (eastern Atlantic) to test whether short-term dispersion of seagrass-associated amphipods differed between day and night, testing the consistency throughout an entire lunar cycle. Replicated artificial seagrass units were deployed, and subsequently retrieved, during the day (from 8:00 am to 18:00 pm) and the night (from 18:00 pm to 8:00 am) on three consecutive days within each of the four moon phases of a complete lunar cycle. We collected 13,467 amphipods corresponding to 32 species and 17 families. Significantly larger abundances of amphipods were collected during the night through the entire moon cycle. The total abundance of amphipods was also affected by the moon phases; under full moon, larger abundances of amphipods dispersed into the artificial seagrass units followed by the third quarter, the new moon and the first quarter. The species density of amphipods per unit followed the same pattern. In conclusion, the short-term dispersion of amphipods living in a seagrass meadow was considerably greater during the night than the day, while dispersion of amphipods was more intense under full moon.     

Winter survival of North American grassland birds is driven by weather and grassland condition in the Chihuahuan Desert

Populations of grassland birds that overwinter in the Chihuahuan Desert are declining more rapidly than other grassland birds, and survival during the non‐breeding season may have a strong influence on population trends of these species. Habitat loss and deterioration due to desertification may be contributing to these declines, and the winter ecology of grassland birds under these changing environmental conditions remains relatively unexplored. To fill this information gap, we estimated the survival of two grassland‐obligate sparrows, Baird's Sparrows (Ammodramus bairdii) and Grasshopper Sparrows (A. savannarum), on their wintering grounds in the Chihuahuan Desert, and investigated the role of habitat structure and weather on survival rates. We deployed radio‐transmitters on Baird's (N = 49) and Grasshopper (N = 126) sparrows near Janos, Chihuahua, and tracked birds from November to March during the winters of 2012–2013 and 2013–2014. Causes of mortality included avian predators, mammals, and possibly weather. We estimated an overall weekly winter survival probability of ? = 92.73% (95% CI[s] = 88.63–95.44%) for Baird's Sparrows in 2012–2013. We estimated a weekly winter survival probability of ? = 93.48% (95% CI[s] = 90.29–96.67%) and ? = 98.78% (95% CI[s] = 97.88–99.68%) for Grasshopper Sparrow in 2012–2013 and 2013–2014, respectively. Weekly winter survival was lower with colder daily minimum temperatures for both species and in areas with taller shrubs for Grasshopper Sparrows, with the shrubs potentially increasing predation risk by providing perches for Loggerhead Shrikes (Lanius ludovicianus). Our results highlight the need to maintain healthy grass structure in wintering areas to provide birds with food, protection from predators, and adequate cover from inclement weather. Our results also demonstrate that the presence of shrubs can lower winter survival, and suggest that shrub encroachment into the winter habitat of these sparrows may be an important driver of their population declines. Shrub removal could increase survival of wintering sparrows in the Chihuahuan Desert by reducing availability of perches for avian predators, thus reducing predation risk.     

Invasive house geckos are more willing to use artificial lights than are native geckos

There is increasing concern about the ecological effects of light pollution, as artificial lighting spreads with urban expansion. While artificial lighting can negatively affect some species, others use it in novel ways. In tropical and subtropical regions, artificial lighting has created a novel niche: the ‘night light’ niche. Geckos living as human commensals (house geckos) are apparently well adapted to occupy this niche. In an urban area in north‐eastern Australia, we found that the invasive Asian house gecko Hemidactylus frenatus (Gekkonidae) occupies a broader range of light environments in the field than does the native gecko Gehyra dubia (Gekkonidae). Experimental removal of the invasive species from a building indicated that it did not behaviourally influence the light environments chosen by the native species in the short term; they continued to use darker areas even after the invasive species was removed. In Y‐maze experiments, neither species showed a significant preference for light or dark areas; however, preliminary data suggest the invasive species was more willing to explore the Y‐maze than the native species. The willingness of H. frenatus to forage closer to lights, where insect abundance is typically higher, might account for its success as a global invader of human environments, even in areas where other gecko species are established.     

Age composition of winter irruptive Snowy Owls in North America

Patterns of winter irruptions in several owl species apparently follow the ‘lack of food’ hypothesis, which predicts that individuals leave their breeding grounds in search of food when prey populations do not allow breeding and are too small to ensure survival. Recent analyses, however, suggest an alternative mechanism dubbed the ‘breeding success’ hypothesis, which predicts that winter irruptions might instead be the result of a very successful breeding season, with a large pool of young birds subsequently migrating south from the breeding grounds. Here we assessed age‐class (juvenile vs. non‐juvenile) composition of winter irruptive Snowy Owls Bubo scandiacus over a 25‐year period (winter 1991–1992 to 2015–2016) between regular (North American Prairies and Great Plains) and irregular wintering areas (northeastern North America) using live‐trapped individuals and high‐resolution images of individual owls. Our results show that the proportion of juveniles (birds less than 1 year of age) varies considerably annually but is positively correlated with irruption intensity in both regions. In irregular wintering areas, it can constitute the majority (up to more than 90%) of winter irruptive Snowy Owls over a large geographical area. These results are consistent with the idea that large winter irruptions at temperate latitudes are not the result of adults massively leaving the Arctic in search of food after a breeding failure but are more likely to be a consequence of good reproductive conditions in the Arctic that create a large pool of winter migrants.     

Behavioral analysis of learning and memory in Anastrepha fraterculus

We evaluate the influence of prior exposure to artificial substrate for oviposition on learning and memory in the fruit fly Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae). Some females were previously exposed to artificial fruits made of water, agar, and blackberry [Rubus spec. (Rosaceae)] or guava [Psidium guajava L. (Myrtaceae)] pulp for 48 and 72 h. We also studied adult flies exposed for 72 h to essential oil of lemongrass [Cymbopogon citratus (DC) Stapf, Poaceae] and adult flies from larvae exposed to the oil. Control females were naive with respect to these experimental substrates. Prior experience with blackberry‐based artificial fruits resulted in an increase in the number of punctures and deposited eggs by A. fraterculus, and memory lasted for up to 72 h. On the other hand, fly behavior was independent of exposure to guava‐based substrate. Prior exposure of 1‐ or 15‐day‐old females to artificial substrate with lemongrass oil modified innate substrate selection behavior. The scent of lemongrass oil during the larval stage modified innate oviposition responses of adult A. fraterculus. The study shows that A. fraterculus females are able to learn and retain information through chemical stimuli released by both host (blackberry and guava) and non‐host (lemongrass) species, and they can use olfactory memory obtained during the larval stage to select oviposition sites.     

Is genome size of Lepidoptera linked to host plant range?

Genome size varies considerably among organisms, largely as the result of differences in the content of non‐coding and/or repetitive DNA, such as introns, pseudogenes, or transposable elements, as well as whole‐genome duplications. Genome size is known to correlate with metabolic rates. Because polyphagy also affects the metabolism, a correlation between diet specialization and genome size can be expected. To test this hypothesis, a study was undertaken with five closely related species of stem borers which are easy to rear under artificial conditions, namely Busseola fusca (Fuller), Busseola segeta (Bowden), Busseola nairobica Le Ru, Sesamia calamistis Hampson, and Sesamia nonagrioides Lefebvre (all Lepidoptera: Noctuidae). However, as the number of species was too low for correlating diet with genome size in Lepidoptera in general, literature data from 16 Lepidoptera species were used in addition. The results pointed to a relationship between genome size and the insect's host plant range in Lepidoptera, but below the family level only, with larger genomes in polyphagous compared to specialist species. In addition, the genome size appeared to be influenced not only by host plant range but also by environmental/climatic conditions. Studies to test this hypothesis should be done strictly below the family level.