Dispersal patterns of endemic alpine butterflies with contrasting population structures:<Emphasis Type="Italic"> Erebia epiphron</Emphasis> and<Emphasis Type="Italic"> E. sudetica</Emphasis>

We studied population sizes and mobility of Erebia epiphron and Erebia sudetica, two high mountain butterflies forming endemic subspecies in the Hrubý Jeseník Mountains, Czech Republic. E. epiphron formed two continuous populations containing 100,000 and 4,500 individuals on alpine grasslands. The butterflies moved freely within their habitats, but movements between the two populations were highly unlikely. E. sudetica formed a system of colonies at timberline sites on valley headwalls and in forest clearings. Two such colonies studied in detail contained 4,500 and 450 adults and were interconnected by limited dispersal. The negative exponential function and the sigmoid function (this assumes flat decrease of movements over short distances) were superior to the inverse power function in fitting mobility data for both species. For E. sudetica, the functions describing movements within a habitat differed significantly from total movements, suggesting different behaviours of dispersing individuals. The habitats of E. epiphron are uniform and highly isolated, favouring free within-habitat mobility but prohibiting leaving their boundaries. The habitats of E. sudetica are diverse and disturbance-dependent; leaving such habitats is less risky, and a source-sink model may explain the persistence of the species in the mountains.     

Life-cycle regulation and life history plasticity in the speckled wood butterfly: are reaction norms predictable?

We investigated whether interpopulational variation in life-cycle regulation and life-history plasticity, in response to photoperiod, is predictable from considerations of what would be the adaptive life cycle and life history in a given environment. The investigation was performed on five populations of the speckled wood butterfly, Pararge aegeria (L.) (Lepidoptera: Nymphalidae), from central and south Sweden, England, Spain and Madeira. Insects from all five populations were reared at all daylengths from 10 h to 20 h at 17^oC. Larval and pupal development times were noted. Predictions were met regarding the type of life-cycle regulation and the shape of reaction norms. Evidence for diapause (larval summer and winter diapause, pupal winter diapause) was found in the three northern populations (P. a. tircis) but not in the two southern populations (P. a. aegeria). Photoperiodic thresholds for diapause induction followed the predicted latitudinal patterns, and this was also the case regarding quantitative regulation of development time (by photoperiod) among directly developing individuals. Under direct development, development time was progressively shorter in shorter daylengms in the two Swedish populations, where this signals progressively later dates. This was not found in the English, Spanish and Madeiran populations where such a response is likely to be maladaptive, because one or more generations of larvae are present before summer solstice. There were also unexpected results, for which we propose preliminary adaptive explanations.     

Disjunct distributions during glacial and interglacial periods in mountain butterflies: Erebia epiphron as an example

Over several decades, the distribution patterns and evolution of alpine disjunct species has become an increasingly discussed subject. Large scale genetic analysis has allowed the resolution of the past range changes and intraspecific evolution of many species, in Europe especially of Mediterranean origin. However, the phylogeographic structures of species with arctic-alpine disjunct distribution patterns are relatively poorly studied. The existing phylogeographic analysis (mostly of alpine plant species) supports disjunct distributions during glacial as well as post-glacial periods for a number of species. However, several questions still remain unresolved and we therefore analysed the Mountain Ringlet Erebia epiphron as a model for such alpine disjunct species. We found strong differentiation into five different lineages supporting five differentiation centres: (i) the eastern Pyrenees, (ii) the mountain ranges between the central Pyrenees and south-western Alps, (iii, iv) two areas along the southern Alps margin and (v) the northern Alps margin. We propose that these patterns evolved due to the humidity requirements of this species, which did not allow survival in the dry glacial steppes, but along the margins of the wetter glaciated high mountain ranges.     

Effect of larval-rearing density on adult life-history traits and developmental stability of the dorsal eyespot pattern in the speckled wood butterfly, Pararge aegeria

Behavioural stresses such as crowding are thought to incur a metabolic cost to insect larvae, and fluctuating asymmetry (FA) has been shown to be a possible indicator of this stress. A study of a Madeiran population of the butterfly Pararge aegeria L. (Lepidoptera: Satyrinae) shows that larval crowding affects larval development and growth, with female larvae being more adversely affected than males. It was predicted that if larval crowding increases FA, male and female P. aegeria adults may show different responses to this stress. The FA of five different wing pattern elements on the dorsal hindwings of adult male and female P. aegeria that had been reared at different larval densities was measured. Crowding in P. aegeria resulted in a trait-specific and sex-specific increase in FA. Although a significant correlation between FA and longevity was not observed, there was a significant correlation with egg-laying rate. Stressed females increased their egg-laying rate. An increased egg-laying rate may carry a further fitness cost through the offspring of stressed females, because high egg-laying rates are associated with a decline in oviposition site quality.     

The role of weather-related habitat use on the impact of the European speckled wood Pararge aegeria on the endemic Pararge xiphia on the island of Madeira

Habitat use and microclimatic constraints on the activity of the endemic Madeiran speckled wood butterfly and European speckled wood were studied in September 1989 and April 1990. The endemic species is the most closely associated with laurel forest and the recently established European speckled wood with pine and eucalyptus forest. The relative abundances of the two species in different sites changes with season, with the endemic species being relatively more common in low level sites in April at the end of the cool season, than in September at the end of the warm summer period. It is suggested that changes of abundance in different locations are related to the thermal biology of the two species. The endemic speckled wood is active at lower air temperature than the European species, and the cool winter period may facilitate occupation of open sunny sites. The activity of the endemic speckled wood is less constrained by cool and dull conditions than is that of the European species, which requires higher temperatures for activity. It is proposed that the activity and behavioural repertoire of the endemic is most suited to climatic conditions in, and structural features of, laurel forest. The European species is most suited for activity in open woodland and agricultural habitats. Interactions between adults of the two species do not indicate direct competition. Changes in the distribution of the two species can be linked to probable changes of habitat on the island of Madeira.     

Intraspecific allozymatic differentiation reveals the glacial refugia and the postglacial expansions of European Erebia medusa (Lepidoptera: Nymphalidae)

Allozyme analysis of Erebia medusa over large regions of Europe revealed a significant population differentiation (F_ST: 0.149 ± 0.016). A UPGMA-analysis showed a division into four major lineages with mean inter-group genetic distances ranging from 0.051 (±0.010) to 0.117 (±0.024). An AMOVA revealed that rather more than two-thirds of the variance between samples was being between these lineages and less than one-third within lineages. An eastern group included the samples from the Czech Republic, Slovakia and north-eastern Hungary. This genetic lineage expressed significantly higher genetic diversity than the other three. A second lineage was formed by the samples from France and Germany. The two samples from western Hungary represent a third delimited lineage and the sample from northern Italy a fourth. We suppose that this genetic differentiation took place during the last ice-age in four disjunct refugia. The genetically more diverse eastern genetic lineage might have evolved in a relatively large refugium in south-eastern Europe. We assume that the other three lineages developed in relatively small relict areas around the Alps. It is likely for the western lineage that its ice-age distribution showed at least one disjunction in late Würm with the consequence of further genetic differentiation. Most probably, the eastern lineage colonized postglacial Central Europe using two alternative routes: one north and one south of the Carpathians. Up to now, neither similar glacial refugia, nor comparable secondary disjunctions in late Würm, are reported for any other animal or plant species.     

宁夏六盘山国家级自然保护区眼蝶群落多样性

蝴蝶是地球生物多样性的重要指示物种之一, 其种群动态及群落结构变化能够揭示环境改变对生态系统的影响。六盘山国家级自然保护区生境优越, 植物区系多样, 孕育了丰富的蝶类资源。为了有效利用环境和保护蝶类资源, 2016-2018年, 作者采用样线调查法, 对宁夏六盘山国家级自然保护区人工植被、针阔混交林、阔叶林、灌木林4种生境中眼蝶亚科昆虫进行了调查, 分析了眼蝶在空间及时间上的动态变化。共记录眼蝶亚科13属19种4,363只, 其中阿芬眼蝶(Aphantopus hyperanthus, 961只)、亚洲白眼蝶(Melanargia asiatica, 637只)、爱珍眼蝶(Coenonympha oedippus, 594只)分别占总数的22%、15%和13%, 为保护区优势种; 蟾眼蝶(Triphysa phryne, 17只)仅占总数的0.39%, 为保护区的稀有种。在空间分布上, 4类生境中针阔混交林眼蝶物种丰富度和优势度低, 多样性指数最高, 不同生境眼蝶群落物种丰富度指数、多样性指数、均匀度指数存在明显差异(P < 0.05), 优势度指数差异不显著。在时间动态上, 2016-2018年眼蝶个体数量呈下降趋势, 物种个体数量高峰期主要发生在8月, 优势种变化明显。因此, 保护宁夏六盘山国家级自然保护区蝴蝶种类多样性刻不容缓。     

中国黛眼蝶属一新种和一新亚种记述(鳞翅目,蛱蝶科,眼蝶亚科)(英文)

记述了中国眼蝶亚科Satyrinae黛眼蝶属Lethe Hbner,18191新种和1新亚种——浅色黛眼蝶Lethe tingeda sp.nov.,比目黛眼蝶宝兴亚种Lethe proxima baoxingensis ssp.nov.,模式标本保存于西北农林科技大学昆虫博物馆。比目黛眼蝶宝兴亚种,新亚种Lethe proxima baoxingensis ssp.nov.(图1～7)新亚种与比目黛眼蝶指名亚种Lethe proxima proxima Leech相似,主要区别是:后翅正面亚缘只有2枚眼斑;前翅反面外横带不规则弯曲;后翅反面Cu2、2A脉间外横线强烈弯折。淡色黛眼蝶,新种Lethe tingeda sp.nov.(图8～14)新种与棕褐黛眼蝶Lethe christophi(Leech)相似,主要区别是:颜色较浅;雄蝶后翅性标斑小,水滴状,覆有黑色毛簇,而非烙斑状;后翅反面cu1室内无眼斑;m3室内眼斑瞳点不扩大;翅反面前后翅外横线不连贯;雄性外生殖器囊突较粗短;钩突近端部背侧隆起较强。     

Fat and sassy: factors underlying male mating success in a butterfly

Theory predicts that male mating success depends on resource holding potential (RHP), which is reflected by proxies of condition, such as body mass, fat content, strength, or weaponry. In species lacking any physical means to inflict injuries upon combatants, such as butterflies, the factors determining mating success are less clear. Against this background, we explored the determinants of male mating success in the tropical butterfly Bicyclus anynana Butler (Lepidoptera: Nymphalidae: Satyrinae), by comparing physiological, immunological, and morphological traits between winning and losing males. Our results showed that successful males are characterized by a better flight performance, evidenced by having longer wings, a heavier thorax, a lighter abdomen, a higher fat content, and higher phenoloxidase expression levels than their unsuccessful counterparts, when being compared after their first mating. Males that won three consecutive trials against the same combatant were also characterized by a better flight performance, having larger forewings, a higher body mass, and a higher fat content. Thus, successful males were larger and in better condition than unsuccessful ones. Strikingly, many differences found indicated an enhanced flight performance for the former, which we suggest ultimately plays the key role for male mating success in B. anynana. As fat is the main energy source for flying insects, being crucial to flight endurance and in turn presumably to male mating success, it may represent a key determinant at the proximate level.