AFLP reveals cryptic population structure in migratory European red admirals (Vanessa atalanta)

1. The genetic differentiation in a migratory butterfly, the red admiral (Vanessa atalanta), was investigated to discern patterns of migratory routes used across Europe. AFLP profiles showed significant differences between almost all sampled locations, but there was no clear pattern of isolation‐by‐distance. 2. Using the software STRUCTURE 2.2, we found two distinct genotype clusters present in different frequencies at all study sites. The frequencies of these genotypic clusters varied significantly between years within the same site. Remarkably few individuals were of mixed ancestry, indicating that some isolating mechanisms are present. Twenty‐seven mtDNA haplotypes were identified but they showed no geographic structure, nor were they related to either of the two genotype clusters identified in the AFLP data. 3. Most field observations of migrating red admirals suggest a regular north–south migration pattern in Europe. Our data indicate both long‐distance migration and a more variable pattern in orientation, since the composition of the two genotypic clusters shows dramatic variation between sites and years in the northern part of the distribution range.     

Understanding the migration ecology of European red admirals Vanessa atalanta using stable hydrogen isotopes

Tracking migratory movement of small animals with variable migration patterns is difficult with standard mark–recapture methods or genetic analysis. We used stable hydrogen isotope (δD) measurements of wings from European red admirals Vanessa atalanta to study several aspects of this species’ migration. In the central part of southern Europe we found large differences in δD values between red admirals sampled in autumn and spring supporting the hypothesis that reproduction takes place in the Mediterranean region during winter. There was also an apparent influx to southern Europe in the spring of individuals with a more southerly origin, since many samples had higher δD values and similar to those expected from coastal areas of North Africa. We found a clear seasonal difference in the δD values of red admirals sampled in northern Europe. Spring migrants arriving in northern Europe generally had high δD values that indicated a southerly origin. In autumn, δD values suggested that red admirals were mostly from regions close to the sampling sites, but throughout the sampling period there were always individuals with δD values suggesting non‐local origins. The migration pattern of this species is supposedly highly variable and plastic. δD differences between individuals in the western part of Europe were generally small making migratory patterns difficult to interpret. However, butterflies from western Europe were apparently isolated from those from north‐eastern Europe, since δD values in the western region rarely corresponded to those of autumn migrants from the north‐east. Use of δD data for inferring butterfly migration in Europe is complex, but our study showed that this technique can be used to help uncover previously unknown aspects of red admiral migration.     

The nature of migration in the red admiral butterfly Vanessa atalanta: evidence from the population ecology in its southern range

1. The migrant Vanessa atalanta (L.) occurs throughout Europe and North Africa. In autumn, populations emigrate from northern and central Europe to the Mediterranean region to overwinter. In the spring, the northern range is recolonised by migrants from the south. The dynamics of the species in the winter range is poorly known. 2. From 1994 to 1999, adults and immatures of V. atalanta were monitored all year round in Mediterranean habitats in north‐east Spain. 3. Data showed that the Catalonia lowlands is an area to which V. atalanta migrates to breed during the winter. Migrants arrive in October and early November and initiate a period of intensive breeding. Larval development occurs throughout the winter until a first annual generation of adults appears in early spring. 4. Most of the butterflies emerging in the spring emigrate and leave the area without breeding. The data suggest strongly that recolonisation of the northern range is by these butterflies not by wintering adults. Altitudinal migration also seems to be a common phenomenon, allowing a further summer generation of adults to occur at high elevations within the Mediterranean region. 5. The complex phenology of V. atalanta in its southern range has evolved as a strategy to track larval resources through space and time. Autumn migration coincides with the greatest availability of the main food plant, Urtica dioica L. Late spring migration occurs by the time food quality is decreasing.     

The effects of methodological limitations in the study of butterfly behavior and demography: a daily study of Vanessa atalanta (Lepidoptera: Nymphalidae) for 22 years

Normally, butterfly behavior and population size are studied intensively for brief periods or occasionally for long periods, not in detail for long periods, producing an incomplete view in both cases. How time limitation affects studies has been unknown for a long time. This paper analyses this problem based on an intensive long term study of Vanessa atalanta (L.) that covered nearly 8000 days, most of them consecutive, for 22 years (April 15, 1977-April 14, 1999), in a subtropical habitat near Orlando, Florida. There is no evidence that ethological studies are affected by their normally brief duration (one year or less), but the analysis of yearly values hid the associations of number of individuals and arrival time with climate. In small areas, isolated population counts lasting less than two weeks are not reliable, according to this study. We found no difference in number of visitors for El Ni?o years. The daily number of visitors was inversely correlated with temperature and precipitation, but arrival time of the first visitor was positively correlated with both. The number of visitors reaches a peak near the end of Winter. The activity period span is greater than in more seasonal climates. Individuals were active even at 10 degrees C and with 9 m/s winds. Individuals with fresh wing condition were most common from January to June. There were 82 atypical cases of individuals arriving before 12:00 hr. Aerial interactions were seen whenever there was more than one individual in the site (i.e. 41% of days, N = 7634 total days). Only once in these 22 years was predation seen.     

Increased abundance of the red admiral butterfly Vanessa atalanta in Britain: the roles of immigration, overwintering and breeding within the country

The migratory butterfly Vanessa atalanta increased in abundance at monitored sites in Britain from 1976 to 1996. Three possible causes of the increase are improved winter survival within Britain, greater breeding success within Britain, and increased immigration.
   Trends during most of the season were similar to those of immigrant or overwintered individuals in spring; thus the evidence does not support greater breeding success in Britain. As abundance in spring was not correlated with abundance in the previous autumn, when trend was taken into account, it seemed unlikely that overwintering in Britain was important. Thus the increase in abundance was probably due to increased immigration. Incidental to the main study, the mean index per site per year was closely correlated with the collated index, the usual measure of annual fluctuations. This agreement suggests that the mean index may be a useful check for trends in monitoring data for other wide-ranging organisms.     

Territorial behavior of the red admiral,Vanessa atalanta (Lepidoptera: Nymphalidae) I. The role of climatic factors and early interaction frequency on territorial start time

We examined the relative importance of climatic factors and population density to territorial start time ofVanessa atalanta males. Start time varies with solar altitude and therefore with seasons. We removed seasonal effects by converting start times to corresponding solar altitudes. Start time solar altitude correlates primarily with ambient temperature (T _a) and secondarily with substrate temperature (T _s), regardless of cloud cover. Overcast cloud cover resulted in later not earlier start times as expected from reduced solar radiation (R) levels. R may affect start time indirectly by affectingT _s and later start times under overcast skies may be a result ofT _s. Start times under solid overcast but not under broken overcast were different than under clear skies, suggesting thatV. atalanta males can use dim sun or blue patches in broken overcast as a start time cue. Early interaction frequency is correlated withT _a and wind direction, but not with start time itself, suggesting that male population density is unimportant compared with climatic factors. We conclude thatV. atalanta has a climate-dependent start time but, also, that maintaining a relatively fixed daily schedule is more important to males than is achieving an optimal body temperature while perching.     

小熊猫夏秋季的昼夜活动节律

2002年5~11月,在邛崃山系宝兴蜂桶寨自然保护区采用无线电遥测技术对6只野生小熊猫的昼夜活动节律进行了研究。结果表明,小熊猫具有晨昏活动的习性,5~11月的平均活动率为0.5286。小熊猫以白昼活动为主,兼夜间活动,白昼的活动率(0.5903±0.0538)高于夜晚活动率(0.4468±0.0413)。每昼夜有(52.86±9.8)%的时间处于活动状态,其中64.53%的活动时间在白昼,35.47%的活动时间在夜晚。每昼夜有两个活动高峰,分别出现在08∶00~10∶00和17∶30~18∶30。在休息时间的分配上,小熊猫每昼夜长休息平均2.07次,持续时间平均3.75小时;中等长度休息1.56次,持续1.59小时;短休息1.21次,持续0.84小时;长休息有44.06%在白昼,55.94%在夜晚。     

Migration and Fisheries of North East Atlantic Mackerel (Scomber scombrus) in Autumn and Winter

It has been suggested that observed spatial variation in mackerel fisheries, extending over several hundreds of kilometers, is reflective of climate-driven changes in mackerel migration patterns. Previous studies have been unable to clearly demonstrate this link. In this paper we demonstrate correlation between temperature and mackerel migration/distribution as proxied by mackerel catch data from both scientific bottom trawl surveys and commercial fisheries. We show that mackerel aggregate and migrate distances of up to 500 km along the continental shelf edge from mid-November to early March. The path of this migration coincides with the location of the relatively warm shelf edge current and, as a consequence of this affinity, mackerel are guided towards the main spawning area in the south. Using a simulated time series of temperature of the shelf edge current we show that variations in the timing of the migration are significantly correlated to temperature fluctuations within the current. The proposed proxies for mackerel distribution were found to be significantly correlated. However, the correlations were weak and only significant during periods without substantial legislative or technical developments. Substantial caution should therefore be exercised when using such data as proxies for mackerel distribution. Our results include a new temperature record for the shelf edge current obtained by embedding the available hydrographic observations within a statistical model needed to understand the migration through large parts of the life of adult mackerel and for the management of this major international fishery.     

Biology and morphology of the immature stages of Hermeuptychia atalanta (Lepidoptera: Nymphalidae: Satyrinae)

This paper describes the morphology of the immature stages (egg, larva and pupa) and larval behavior of the butterfly Hermeuptychia atalanta, a common and widespread species of satyrinae in South America. Eggs are white and spherical, laid singly on leaves of grasses. The first instar has a light-green body and dark-brown head; all remaining instars present body and head capsule light green. Larvae have no spines, and general morphology is similar to other species of the subtribe Euptychiina.     

Vanessa cardui adipokinetic hormone (Vanca-AKH) in butterflies and a moth

Small neuropeptides of the adipokinetic hormone/red pigment-concentrating hormone (AKH/RPCH) family regulate energy metabolism in insects. Within lepidopterans, the nonapeptide Manduca sexta AKH (Manse-AKH) represents a widely occurring AKH, whereas the decapeptide Helze-HrTH (at first isolated from Heliothis zea) seems to be restricted to moths. Here we show that Vanca-AKH, a non-amidated undecapeptide which we recently found in the painted lady butterfly, Vanessa cardui, is also present in the retrocerebral complex of several other butterflies (Danaus plexippus, Precis coenia, Aglais urticae) and a moth (Spodoptera frugiperda). This study also demonstrates the power of modern nano-electrospray-quadrupole TOF tandem mass spectrometry in the sequence confirmation of peptides from minute amounts of small neuropeptides.     

Modelling Directional Guidance and Motility Regulation in Cell Migration

Although cell migration is an essential process in development, how cells reach their final destination is not well understood. Secreted molecules are known to have a migratory effect, but it remains unclear whether such molecules act as directional guidance cues or as motility regulators. There is potential to use signalling molecules in new medical therapies, so it is important to identify the exact role these molecules play. This paper focuses on distinguishing between inhibitory and repulsive effects produced by signalling molecules, based on recent experiments examining the effect of Slit, a secreted protein, on the migration of neurons from the brain. The primary role of Slit, whether it is an inhibitor or repellent of neurons, is in dispute. We present population-level continuum models and recast these in terms of transition probabilities governing individual cells. Various cell-sensing strategies are considered within this framework. The models are applied to the neuronal migration experiments. To resolve the particular role of Slit, simulations of the models characterising different cell-sensing strategies are compared at the population and individual cell level, providing two complementary perspectives on the system. Difficulties and limitations in deducing cell migration rules from time-lapse imaging are discussed.     

Rheoreaction of Some Juvenile Cyprinids During Autumn Contranatant Migration

Journal of Ichthyology - The contranatant migration of juvenile cyprinids was studied in the Volga River delta in September–November 2016. A motivational component of rheoreaction (the ratio...     

Burn Injury Reduces Neutrophil Directional Migration Speed in Microfluidic Devices

Thermal injury triggers a fulminant inflammatory cascade that heralds shock, end-organ failure, and ultimately sepsis and death. Emerging evidence points to a critical role for the innate immune system, and several studies had documented concurrent impairment in neutrophil chemotaxis with these post-burn inflammatory changes. While a few studies suggest that a link between neutrophil motility and patient mortality might exist, so far, cumbersome assays have prohibited exploration of the prognostic and diagnostic significance of chemotaxis after burn injury. To address this need, we developed a microfluidic device that is simple to operate and allows for precise and robust measurements of chemotaxis speed and persistence characteristics at single-cell resolution. Using this assay, we established a reference set of migration speed values for neutrophils from healthy subjects. Comparisons with samples from burn patients revealed impaired directional migration speed starting as early as 24 hours after burn injury, reaching a minimum at 72–120 hours, correlated to the size of the burn injury and potentially serving as an early indicator for concurrent infections. Further characterization of neutrophil chemotaxis using this new assay may have important diagnostic implications not only for burn patients but also for patients afflicted by other diseases that compromise neutrophil functions.     

辽宁老铁山雀形目鸟类秋季迁徙初探

2000~2004年秋在辽宁旅顺老铁山自然保护区,通过鸟类环志和直接观察的方法,对该地区雀形目(Passeriformes)鸟类秋季迁徙规律进行了研究。5年共环志11 040只雀形目鸟类,发现8种保护区新记录种。结果表明,鸟类迁徙高峰大都集中在10月中下旬;气候条件与鸟类迁徙关系密切;不同年份优势种及种群数量均不同;鸟类的迁徙具有一定的顺序性和集群现象,但不同种类迁徙的种群大小又有差别;2004年雀形目鸟类的种类和数量都明显少于前4年,略有下降趋势。     

Directional hearing in the barn owl (Tyto alba)

Summary The acoustical properties of the external ear of the barn owl (Tyto alba) were studied by measuring sound pressure in the ear canal and outer ear cavity. Under normal conditions, pressure amplification by the external ear reaches about 20 dB between 3–9 kHz but decreases sharply above 10 kHz. The acoustic gain curve of the outer ear cavity alone is close to that of a finite-length exponential horn between 1.2–13 kHz with maximum gain reaching 20 dB between 5–9 kHz. Pressure gain by the facial ruff produces a maximum of 12 dB between 5–8 kHz and decreases rapidly above 9 kHz.The directional sensitivity of the external ear was obtained from pressure measurements in the ear canal. Directivity of the major lobe is explained, to a first approximation, by the sound diffraction properties of a circular aperture. Aperture size is based on the average radius (30 mm) of the open face of the ruff. Above 5 kHz, the external ear becomes highly directional and there is a 26° disparity in elevation between the acoustic axis of the left and right ear. In azimuth, directivity patterns are relocated closer to the midline as frequency increases and the acoustic axis moves at a rate of 20°/octave between 2–13 kHz. Movement of the axis can be explained, to a first approximation, by the acoustical diffraction properties of an obliquely truncated horn, due to the asymmetrical shape of the outer ear cavity.The directional sensitivity of the barn owl ear was studied by recording cochlear microphonic (CM) potentials from the round window membrane. Between 3–9 kHz, CM directivity patterns are clearly different to the directivity patterns of the external ear; CM directionality is abruptly lost above 10 kHz. Above 5 kHz, CM directivity patterns are characterized by an elongated major lobe containing the CM axis, forming a tilted band of high amplitude but low directionality (CM axial plane), closely bordered by minima or nulls. The highest directionality is found in theCM directional plane, approximately perpendicular to the CM axial plane. The left and right ear axial planes are symmetrical about the interaural midline (tilted 12° to the right of the midline of the head) and inclined by an average of 60° to the left and right respectively. In azimuth, the CM axis moves towards the midline at a rate of 37°/octave as frequency increases from 2–9 kHz, crossing into contralateral space near 7 kHz. In the CM directional plane, the directivity of the major lobe suggests that a pressure gradient may occur at the TM. The region of frontal space mapped by movement of the CM axis in azimuth closely matches the angle of sound incidence which would be expected to produce the maximum driving pressure at the TM. It is suggested that acoustical interference at the TM results from sound transmission through the interaural canal and therefore the ear is inherently directional. It is proposed that ear directionality in the barn owl may be explained by the combined effect of sound diffraction by the outer ear cavity and a pressure gradient at the TM.Abbreviations CM cochlear microphonic - RMS root mean square - SPL sound pressure level - TM tympanic membrane     

Stress-induced color-pattern modifications and evolution of the Painted Lady butterflies Vanessa cardui and Vanessa kershawi

It has been proposed that phenotypic plasticity and genetic assimilation through natural selection partly determine the direction of divergent selection that eventually results in speciation. To elucidate a process of butterfly color-pattern evolution and speciation in the light of this hypothesis, morphological and physiological differences between a pair of sister species, the Painted Lady butterfly Vanessa cardui and the Australian Painted Lady butterfly Vanessa kershawi, were investigated. Ten different traits of wing color-pattern were indicated, most of which concerned the darker coloration of V. kershawi, with the notable exception of the blue foci at the center of the black focal elements only in V. kershawi. Differences in behavior and life history between the two species appeared to be minimal, but importantly, V. kershawi tends to prefer a "stressful" arid environment. The experimental treatment of pupae of V. cardui either by low temperature or by injection of thapsigargin, a stress-inducing chemical, readily produced individuals with the darker coloration and the blue foci as a result of a general stress response. These stress-induced color-pattern modifications were considered to be the revelation of phenotypic plasticity in V. cardui. Taken together, I propose that the ancestral species of V. kershawi had similar phenotypic plasticity. Natural selection exploited this plasticity and shaped the present V. kershawi as an independent species, whose specific color-pattern traits are by-products of this adaptation process.     

Proboscis musculature in the butterfly Vanessa cardui (Nymphalidae, Lepidoptera): settling the proboscis recoiling controversy

Krenn, H. W. 2000. Proboscis musculature in the butterfly Vanessa cardui (Nymphalidae, Lepidoptera): settling the proboscis recoiling controversy. —Acta Zoologica (Stockholm) 81 : 259–266 The proboscis of Vanessa cardui (Nymphalidae) contains two basal galeal muscles and two different series of numerous oblique muscles. Both muscle series extend from the proximal region up to the tip‐region; the individual muscles of each series run a constant course throughout the proboscis. In contrast to other butterflies, the knee bend region does not have additional types of muscles. The analysis of shock‐frozen proboscises reveals that the dorsal wall is arched outwardly in the uncoiled, feeding position whereas in the coiled, resting position the dorsal proboscis wall is flat or concave. This results in a significantly greater cross‐sectional area due to the significantly greater dorso‐ventral diameter in uncoiled proboscises. After freezing the proboscis in its distal region, it can still be uncoiled, however, it cannot be fully recoiled. These morphometric and experimental results indicate that the oblique proboscis muscles are responsible for recoiling the proboscis to the resting position.