Migration in butterflies: a global overview

Insect populations including butterflies are declining worldwide, and they are becoming an urgent conservation priority in many regions. Understanding which butterfly species migrate is critical to planning for their conservation, because management actions for migrants need to be coordinated across time and space. Yet, while migration appears to be widespread among butterflies, its prevalence, as well as its taxonomic and geographic distribution are poorly understood. The study of insect migration is hampered by their small size and the difficulty of tracking individuals over long distances. Here we review the literature on migration in butterflies, one of the best-known insect groups. We find that nearly 600 butterfly species show evidence of migratory movements. Indeed, the rate of ‘discovery’ of migratory movements in butterflies suggests that many more species might in fact be migratory. Butterfly migration occurs across all families, in tropical as well as temperate taxa; Nymphalidae has more migratory species than any other family (275 species), and Pieridae has the highest proportion of migrants (13%; 133 species). Some 13 lines of evidence have been used to ascribe migration status in the literature, but only a single line of evidence is available for 92% of the migratory species identified, with four or more lines of evidence available for only 10 species – all from the Pieridae and Nymphalidae. Migratory butterflies occur worldwide, although the geographic distribution of migration in butterflies is poorly resolved, with most data so far coming from Europe, USA, and Australia. Migration is much more widespread in butterflies than previously realised – extending far beyond the well-known examples of the monarch Danaus plexippus and the painted lady Vanessa cardui – and actions to conserve butterflies and insects in general must account for the spatial dependencies introduced by migratory movements.     

Sexual and seasonal differences in the frequency of beak marks on the wings of two Lethe butterflies

To assess bird predation pressure on butterflies, I investigated beak marks on the wings of two Lethe butterflies for 3 years in secondary temperate forests. If bird predation had significant effects on average longevity of butterflies, and if the number of specimens preyed upon was proportionate to the number of beak-marked specimens, the beak mark frequency would be negatively correlated with average longevity of a butterfly. Bird predation pressure is generally thought to influence average longevity of butterflies. Therefore, if there is a negative correlation between beak mark frequency and average longevity, bird predation pressure would be reflected in beak mark frequency. Beak mark frequency was negatively correlated with longevity in Lethe diana (Butler), the more abundant of the two species; thus, the beak mark frequency was considered to be a suitable index of bird predation pressure on the butterflies investigated in this study. In both Lethe species, beak mark frequency was higher in females than in males. Because female butterflies have a relatively smaller thorax and flight muscles and a larger abdomen that contains eggs, they are presumably weaker or less agile fliers than males, and are probably attacked more easily by birds. In autumn, butterflies were heavily attacked by birds irrespective of sex and species. Because the numbers of lepidopteran larvae, which are the preferred prey of many birds, decreased in autumn, birds were thought to shift their diets to alternative prey such as adult butterflies.     

Australian parasitic Ogyris butterflies: east–west divergence of highly‐specialized relicts

Not all butterflies are innocuous plant‐feeders. A small number of taxa in the family Lycaenidae have graduated from mutualistic partnerships with ants to predatory or parasitic associations. These highly‐specialized life histories, involving butterfly larvae living inside ant colonies, are often associated with rarity and vulnerability to extinction. In the present study, we examined the evolutionary relationships of a poorly‐known group of seven taxa herein referred to as the idmo‐group within the Australian lycaenid genus Ogyris. The idmo‐group has a relictual distribution across southern Australia and includes taxa with highly‐specialized phytophagous and myrmecophagous life histories. A phylogeny based on mitochondrial DNA (cytochrome oxidase I and cytochrome b] and the nuclear DNA locus elongation factor 1α (EF1α), generally agrees with current taxonomy and supports the recent elevation of endangered taxon Ogyris halmaturia to full species status. The transition to myrmecophagy was dated to the mid‐Miocene (approximately 16 Mya), when southern Australia experienced a humid climate and extensive mesic biome. The arid Nullarbor Plain, a major biogeographical feature of central southern Australia, divides the remnants of this mesic biome into south‐eastern and south‐western isolates. Late‐Miocene to Pliocene divergence estimates for polytypic Ogyris species across the Nullarbor were older than estimates made for similarly distributed birds, butterflies, mammals, and reptiles, which mostly date to the Pleistocene. The concept of highly‐specialized life histories as evolutionary dead‐end strategies is well exemplified by the idmo‐group. Data compiled on the known extant subpopulations for idmo‐group taxa show that all of these extraordinary butterflies are scarce and several face imminent threat of extinction. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 473–484.     

Multi‐generational long‐distance migration of insects: studying the painted lady butterfly in the Western Palaearctic

Long‐range, seasonal migration is a widespread phenomenon among insects, allowing them to track and exploit abundant but ephemeral resources over vast geographical areas. However, the basic patterns of how species shift across multiple locations and seasons are unknown in most cases, even though migrant species comprise an important component of the temperate‐zone biota. The painted lady butterfly Vanessa cardui is such an example; a cosmopolitan continuously‐brooded species which migrates each year between Africa and Europe, sometimes in enormous numbers. The migration of 2009 was one of the most impressive recorded, and thousands of observations were collected through citizen science programmes and systematic entomological surveys, such as high altitude insect‐monitoring radar and ground‐based butterfly monitoring schemes. Here we use V. cardui as a model species to better understand insect migration in the Western Palaearctic, and we capitalise on the complementary data sources available for this iconic butterfly. The migratory cycle in this species involves six generations, encompassing a latitudinal shift of thousands of kilometres (up to 60 degrees of latitude). The cycle comprises an annual poleward advance of the populations in spring followed by an equatorward return movement in autumn, with returning individuals potentially flying thousands of kilometres. We show that many long‐distance migrants take advantage of favourable winds, moving downwind at high elevation (from some tens of metres from the ground to altitudes over 1000 m), pointing at strong similarities in the flight strategies used by V. cardui and other migrant Lepidoptera. Our results reveal the highly successful strategy that has evolved in these insects, and provide a useful framework for a better understanding of long‐distance seasonal migration in the temperate regions worldwide.     

Differences in phenotypic traits and migratory strategies between eastern North American monarch butterflies,Danaus plexippus (L.)

The eastern North American population of the monarch butterfly (Danaus plexippus plexippus) has different migratory routes. The majority fly to overwintering colonies in Mexico and others take an eastern route through Florida and Cuba. Monarchs migrating through Florida–Cuba do not overwinter and are mostly found nectaring and flying close to vegetation. This present study explores whether Florida–Cuba versus Mexican migrants differ in (1) phenotypic traits important for migration (e.g. wing size and condition, lipid and lean mass content, and reproductive status) and (2) migratory strategies. The monarch natal grounds (e.g. migrants versus residents) were determined through thin‐layer chromatography cardenolide fingerprint and stable isotopes (hydrogen δ²H and carbon δ¹³C). In addition, wing size and condition, lipid and lean mass, and reproductive status were determined. The results suggest that Mexican migrants are better suited for longer sustained flights and successful overwinter periods as a result of larger wings in better condition, reproductive diapause, and significant fat content. By contrast, Florida–Cuba migrants are more suited for shorter flights and opportunistic migratory strategies, given that their wings were in poor condition, as well as the active reproductive status of > 50% of these butterflies and their significantly low fat content. Eastern monarch migration is more complex and diverse than previously assumed. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Butterfly community ecology: the influences of habitat type,weather patterns,and dominant species in a temperate ecosystem

We compared variation in butterfly communities across 3 years at six different habitats in a temperate ecosystem near Boulder, Colorado, USA. These habitats were classified by the local Open Space consortium as Grasslands, Tallgrass, Foothills Grasslands, Foothills Riparian, Plains Riparian, and Montane Woodland. Rainfall and temperature varied considerably during these years. We surveyed butterflies using the Pollard‐Yates method of invertebrate sampling and compared abundance, species richness, and diversity across habitats and years. Communities were most influenced by habitat, with all three quantitative measures varying significantly across habitats but only two measures showing variation across years. Among habitats, butterfly abundance was higher in Plains Riparian sites than in Montane Woodland or Grassland sites, though diversity was lowest in Plains Riparian areas. Butterfly species richness was higher in Foothills Riparian sites than it was in all but one other habitat (Tallgrass). Among years, butterfly abundance and species richness were lower during the year of least rainfall and highest temperatures, suggesting a substantial impact of the hot, dry conditions. Across habitats and years, butterfly abundance was consistently high at Plains Riparian and Foothills Riparian sites, and richness and diversity were consistently high in Foothills Riparian areas. These two habitats may be highly suitable for butterflies in this ecosystem, regardless of weather conditions. Generally low abundance and species richness in Montane Woodlands sites, particularly in 2002, suggested low suitability of the habitat to butterflies in this ecosystem, and this may be especially important during drought‐like conditions. Finally, to examine the effect that the presence of the very abundant non‐native species Pieris rapae L. (Lepidoptera: Pieridae) has on these communities, we re‐analyzed the data in the absence of this species. Excluding P. rapae dramatically reduced variation of both butterfly abundance and diversity across habitats, highlighting the importance of considering community membership in analyses like ours.     

Butterfly communities in South Australian urban reserves: Estimating abundance and diversity using the Pollard walk

Abstract Remnant habitats within and surrounding urbanized areas are becoming increasingly important for maintaining butterfly diversity. The ‘Pollard walk’ protocol has been used widely overseas to estimate and monitor species diversity and abundance of butterflies. However, there has been limited use of this technique in Australia. Here, we used the Pollard walk method to estimate the diversity of butterflies at three urban sites around Adelaide, South Australia: Belair National Park (BNP), Shepherds Hill Recreation Park (SHRP) and Brownhill Creek Recreation Park (BCRP). In total, 21 species of butterfly were detected across the three sites. Pollard walks detected butterfly species from five families, including rare and highly localized lycaenid and hesperiid species. The highest diversity of species was found at BCRP (16) followed by BNP (14) and SHRP (14). Multivariate analysis on the data revealed a distinct and temporally variable butterfly community at BNP when compared with the SHRP and BCRP. The results of this study show that the Pollard walk can be effectively used to distinguish communities and detect a wide variety of butterflies, including cryptic and rare species, within urban habitats of Adelaide.     

Phylogenetic relationships,biogeography and diversification of Coenonymphina butterflies (Nymphalidae: Satyrinae): intercontinental dispersal of a southern Gondwanan group?

The origins, evolutionary history and diversification of the Australian butterfly fauna are poorly known and uncertain. Two competing hypotheses have been proposed to explain the occurrence of butterflies on this isolated continental landmass. The common view is that all Australian butterflies entered the continent relatively recently from the northern hemisphere via Southeast Asia and/or mainland New Guinea (i.e. northern dispersal origin hypothesis). The alternative view is that part or all of the Australian butterfly fauna ultimately evolved in remnant or Southern Gondwana when Australia was connected to South America through Antarctica (i.e. Southern Gondwanan origin hypothesis). However, robust phylogenies with strong support for monophyly are lacking for the majority of Australian endemic butterfly lineages, thereby precluding determination of their systematic relationships and hence their geographic origins. Here, we use molecular data to reconstruct phylogenetic relationships of the globally distributed butterfly subtribe Coenonymphina (Satyrinae: Satyrini). This group represents a major component of the butterfly fauna of the wider Australasian region, with 19 genera and 71 species endemic to the region. Dating estimates extrapolated from secondary calibration sources indicate that the subtribe arose c . 48 Ma (95% credibility interval, 52–42 Ma), and the crown group first diverged in the Eocene (c . 44 Ma, 95% credibility interval 51–37 Ma). Rapid speciation events subsequently followed around the Eocence–Oligocene boundary, resulting in a near‐hard polytomy comprising short basal branches with nodes that are difficult to resolve. Based on strongly supported phylogenetic relationships and estimates of divergence times, we conclude that the group probably had its origin in the fragment of Southern Gondwana consisting of Australia, Antarctica and South America. However, we are unable to rule out the northern dispersal scenario, particularly as Coenonymphina are closely related to a set of predominantly Asian lineages. Dispersal and extinction events following the final break‐up of Gondwana have played a pivotal role in shaping the extant distributions of the group.     

Kitam Bird Sanctuary,the only low elevation protected area of Sikkim: A conservation hotspot for butterflies in the Eastern Himalaya

The lowland areas of the Himalayan region are subjected to immense anthropogenic pressure because of least representation in the protected area network. Kitam Bird Sanctuary is the only representative protected area that occurs below 1000 m in Sikkim state of India (a part of globally significant biodiversity hotspot of Himalayas) and serves as the refuge for various species of flora and fauna. Here we studied butterfly diversity and community composition in Kitam Bird Sanctuary (a small protected area of 6 km² geographical area) following point count method spread across predetermined transects. Altogether 1674 butterflies belonging to 111 species and six families were recorded after completion of 240 point counts. Among these, 18 species are federally protected under the Wildlife (Protection) Act (1972) of India. Most of the butterflies were forest specialist in terms of habitat preference, whereas based on host plant specificity, the butterfly community was mostly dominated by generalist feeder (Oligophagous II and Polyphagous). Butterfly community parameters showed a strong correlation with habitat variables. While Kitam Bird Sanctuary is primarily designated for conservation of lowland birds, the high diversity of butterflies both in terms of taxonomic richness and trait composition suggests that the sanctuary harbors an ideal habitat for butterflies of the tropical region and invites conservation attention.     

Diet breadth and host plant diversity of tropical- vs. temperate-zone herbivores: South-East Asian and West Palaearctic butterflies as a case study

1. Data on host plant associations of butterflies (Papilionoidea, excluding Hesperiidae) from two biogeographical regions were used to investigate (1) whether tropical herbivores are more narrowly specialized with regard to host plant choice than those of northern temperate zones, and (2) whether tropical butterflies show a greater diversity of host plant affiliations. 2. There was no evidence for a more restricted diet breadth of tropical butterflies, with diet breadth being measured as number of host plant families used per species. In the families Papilionidae, Pieridae, and Nymphalidae, host plant ranges of West Palaearctic and South-East Asian species are similar, whereas in one speciose group within the Lycaenidae, the Polyommatini, tropical species are significantly more polyphagous. 3. Diet breadth also differs among higher butterfly taxa. While Papilionidae, Pieridae, the nymphalid subfamilies Satyrinae, Morphinae, Libytheinae and Apaturinae, as well as the temperate-zone Polyommatini in the Lycaenidae are composed predominantly of host specialists, the degree of polyphagy is higher among the remaining nymphalid subfamilies and in many lycaenids. These results challenge strongly the view that tropical herbivores are generally more specialized in this regard than herbivores of higher latitudes. Rather, chemical constraints and phylogenetic conservatism shape host plant associations in many taxa in such a way that differences between temperate and tropical representatives are slight. 4. Host plant diversity, measured as the number of plant families used per butterfly family and by application of the log-series model, is much higher in South-East Asian Nymphalidae and Lycaenidae (the two largest families) than in their Western Palaearctic relatives. No such differences are observed in the Papilionidae and Pieridae (the two smaller families). Besides effects of sample size, the strong association of papilionid and pierid butterflies with plants characterized by a small set of classes of secondary plant compounds might generally restrict their capability to utilize a broader taxonomic range of host plants. 5. The results indicate that high floral diversity can be reflected by higher diversity of host plant affiliations of herbivores, but taxonomic idiosyncrasies render it difficult to draw generalized conclusions.     

Back to Africa: autumn migration of the painted lady butterfly Vanessa cardui is timed to coincide with an increase in resource availability

1. The painted lady Vanessa cardui is a long‐range migratory butterfly that performs an annual multi‐generational round‐trip between Europe and Africa. Each autumn it returns to northwest (NW) Africa, presumably to track changes in resources that follow a predictable climate‐related spatio‐temporal pattern. 2. Data on the abundance of adult and immature stages in the Maghreb in 2014–2016 are used to test several hypotheses regarding the autumn migration of this species. 3. A strong seasonal migratory strategy was confirmed by the all but total absence of the species in NW Africa at the end of summer and the arrival of huge numbers migrants in October and November. Migration was timed to coincide with an increase in host plant availability but not with any increase in nectar sources. 4. Flower abundance was the main predictor of adult abundance in autumn, with Ditrichia viscosa, Verbesina encelioides, and Medicago sativa being key resources that attracted enormous numbers of butterflies to oases, ruderal habitats, and oueds. The distribution of immature stages was strongly predicted by host plant abundance (with traditional agriculture representing the most important breeding habitat) and latitude (most breeding occurred in the south of the region). Also, both adults and immature stages were more common inland than in coastal areas. 5. Changes in age structure of the adult population were also noted. The number of fresh adults slowly increased, indicating that butterflies did not return in a single wave and that the first offspring of the first returners were already emerging when some butterflies were still arriving.     

Are butterflies and moths useful indicators for restoration monitoring? A pilot study in Sydney's Cumberland Plain Woodland

Summary   Moths and butterflies are strongly associated with vegetation structure and composition, which makes them a suitable indicator taxon for various ecological studies. Despite a good knowledge of many Australian lepidopteran taxa, they have rarely been used for restoration assessment. To explore the feasibility of using Lepidoptera as an indicator taxon for restoration monitoring in Australia, we used it to evaluate the success of a large-scale revegetation program in western Sydney. We compared moth and butterfly assemblages sampled with relatively low intensity in unrestored pastures, revegetated pastures and remnants of endangered Cumberland Plain Woodland (restoration aim). A light-trap survey of moth assemblages showed no significant differences in moth species richness and composition between any of the treatments with traps in revegetated areas producing most species rich samples. Butterfly surveys conducted over a 1-year period showed a considerable increase in butterfly species richness in revegetated areas compared to pastures, while forest remnants still had twice as many butterfly species compared to revegetated areas. Current revegetation practices employed to restore Cumberland Plain Woodland increased the diversity of lepidopteran assemblages, however, it is not clear whether they are on a trajectory towards the reference assemblages of forest remnants. Our study demonstrates that Lepidoptera, particularly butterflies, has a potential for broader application as an indicator group in restoration monitoring in Australia.     

Evolutionary systematics of the Australian Eocyzicus fauna (Crustacea: Branchiopoda: Spinicaudata) reveals hidden diversity and phylogeographic structure

Although ‘large branchiopods’ are an important faunal element of the temporary water bodies in Australia's vast (semi)arid regions, knowledge of their diversity, distribution and ecology is still poor. Here, on the basis of one mitochondrial [cytochrome oxidase subunit I (COI)] and three nuclear (EF1α, ITS2 and 28S) markers, we present new data relating to the diversity and phylogeography of eastern and central Australian Eocyzicus (Spinicaudata) fauna. Using a combination of phylogenetic, haplotype network and DNA barcoding analyses of COI, 312 individuals were grouped into eleven main lineages. To infer whether these lineages are reproductively isolated from each other (the prerequisite for species delineation according to the Biological or Hennigian Species Concepts), separate analyses of each nuclear marker were performed on a subset of specimens. Although some lineages are non‐monophyletic in the analysis of one nuclear marker, this is mostly attributed to processes such as incomplete lineage sorting rather than ongoing reproduction. The eleven lineages translate into at least seven species whose reproductive isolation is additionally indicated by sympatry, including both Australian Eocyzicus species previously described. Another three lineages may constitute further species, but their clear allopatric distribution rendered the test for reproductive isolation inapplicable. One lineage appears not to be reproductively isolated and is therefore considered a genetically distinct lineage within one of the other species, and one divergent lineage within E. argillaquus may constitute an additional species. Although sympatry is very common – six species occur in the central Paroo River catchment in eastern Australia, for instance – syntopic occurrence is rare. It is possible that a combination of differing habitat preferences and priority effects inhibits the presence of more than one Eocyzicus species per water body. There is little to no genetic differentiation between certain populations of the species found in eastern and central Australia (e.g. the Murray–Darling Basin, the Bulloo River catchment and the eastern and northern Lake Eyre Basin; LEB), suggesting high dispersal rates within this large area. Between the central Australian populations themselves, however (e.g. those inhabiting the central and western LEB), genetic differentiation is pronounced, probably as a result of the lack of abundance of important dispersal vectors (aquatic birds) and the lower diversity and density of suitable habitats in the area. The most prominent biogeographical break exists towards north‐eastern Australia (north‐east LEB), which does not share species with any other region studied.     

Across a migratory divide: divergent migration directions and non‐breeding grounds of Eurasian reed warblers revealed by geolocators and stable isotopes

Migratory divides represent narrow zones of overlap between parapatric populations with distinct migration directions and, consequently, expected divergent non‐breeding distributions. The composition of the mixed population at a migratory divide and the corresponding non‐breeding ranges remain, however, unknown for many Palaearctic‐African migrants. Here, we used light‐level geolocation to track migration direction and non‐breeding grounds of Eurasian reed warblers Acrocephalus scirpaceus from three breeding populations across the species’ migratory divide. Moreover, by using feathers grown at non‐breeding grounds, we quantified stable isotope composition for individuals with known southwestern (SW) and southeastern (SE) migration directions. On a larger sample per population, we then assessed the proportions of SW‐ and SE‐migrating phenotypes in each of the three populations. All tracked reed warblers from Germany and two thirds of the birds tagged from the Czech population headed initially SW. Nevertheless, about one third of the birds from the Czech site migrated towards SE. No tracking data have been obtained for the Bulgarian population. The initial migration direction determined by geolocators was a strong predictor of the non‐breeding region, with SW migrants staying in west Africa and SE migrants in central Africa. Feather δ³⁴S and δ¹⁵N values confirmed the predominance of SW migrants in the German population, the co‐occurrence of SW and SE migrants in the Czech population, and indicated a high (72%) proportion of SE migrants in the Bulgarian population. Thus, the combined approach of geolocator tracking and stable isotopic assignments provided clear evidence for the existence of a migratory divide in the southeast of central Europe and predicted non‐breeding range in central and central‐eastern Africa for the eastern population.     

Insular biogeography of the montane butterfly faunas in the Great Basin: comparison with birds and mammals

Summary Butterfly species lists were assembled for 18 Great Basin mountain ranges for which distributional data on mammals and birds have been analysed previously by other workers. The ranges represent remnant islands of the boreal habitat that once was continuous across the Great Basin but is now restricted to higher elevations as a result of climatic change at the close of the Pleistocene. The effects of biogeographic factors (area, distance, elevation) and habitat diversity on butterfly species number were examined. The Great Basin boreal butterfly faunas were found to be depauperate overall relative that of the principal mainland source, the Rocky Mountains, and were found to have fewer species than predicted by the mainland species-area data. However, only a weak area effect, and no distance effect, was detected by bivariate and multivariate analysis. Furthermore, the habitat diversity score found to explain virtually all the variation in bird species number in the same ranges in previous studies is only marginally significantly correlated with butterflies. When the butterflies are subdivided according to their vagility, the relative differences in the species-area correlation and slope (z-value) between the vagility categories were consistent with those found previously for mammals and birds, and, as predicted by theory, less vagile taxa exhibit higher species-area correlations and z-values. Overall, differences in the insular biogeography of buttterflies and vertebrates seem to reflect fundamental ecological differences between the taxa.     

Long distance migration of insects to a subantarctic island

Transoceanic migration of four species of macrolepidoptera to subantarctic Macquarie Island has been detected in 7 out of 33 years during the period 1962–96 and is restricted to spring and autumn. Analyses of synoptic charts during the migration period show that autumn immigrants originated from New Zealand and comprised a single species of noctuid moth,Agrotis ipsilon (Walker). Spring immigrants originated from Australia and comprised two noctuids, Dasypodia selenophora Guenée and Persectania ewingii Westwood and a butterfly, Vanessa kershawi (McCoy). Autumn migrations were associated with depressions in the southern Tasman Sea. Spring migrations were associated with the eastward passage of prefrontal airflows ahead of cold fronts which extended from southern Australia to the west of Macquarie Island. In an analysis of one of these events, winds exceeded 30 ms^?1 at 300 m altitude and could have transported migrants from Tasmania to Macquarie Island overnight in less than 10 h. Flight activity was assisted by the presence of a nocturnal temperature inversion that maintained upper air temperatures above 5 °C. The effect of potential global warming on the migration and colonization of Macquarie Island by insects is discussed.     

Does Müllerian Mimicry Work in Nature? Experiments with Butterflies and Birds (Tyrannidae)1

The selective advantage of Müllerian mimicry in nature was investigated by releasing live mimetic and nonmimetic butterflies close to wild, aerial‐hunting tropical kingbirds (Tyrannus melancholicus) and cliff‐flycatchers (Hirundinea ferruginea) in three Amazon habitats (rain forest, a city, and “canga” vegetation). Only mimetic butterflies elicited sight‐rejections by birds, but protection conferred by mimicry was restricted to sites in which both predators and mimics co‐occurred, as in the case of six mimicry rings at a forest site and two at a city site. Most other Müllerian mimics released at city and canga vegetation were heavily attacked and consumed by birds. These results appear to reflect the birds’previous experiences with resident butterfly faunas and illustrate how birds’discriminatory behavior varied among habitats that differed in butterfly species and mimicry ring composition.     

小兴安岭凉水自然保护区蝶类多样性

2012—2013年选取原始阔叶红松林、人工林、天然次生林和灌丛草甸4种典型植被生境,对小兴安岭凉水自然保护区的蝶类进行了系统研究。共捕获蝶类1438头,分属7科47属76种,4种植被生境中蝶类群落优势类群均为蛱蝶科,不同生境蝶类群落相似性与生境植被类型密切相关。计算分析了4种植被生境中蝶类多样性指数、物种丰富度、优势度指数、均匀度指数和种-多度关系,结果表明:3种森林生境蝶类多样性大于灌丛草甸,原始阔叶红松林蝶类具有最高的多样性指数、较高的物种丰富度、均匀度指数以及最低的优势度指数,种-多度分布为对数正态分布,说明环境质量优越,最适合蝶类生存和繁衍;灌丛草甸蝶类的多样性指数、物种丰富度和均匀度指数均为最低,而优势度指数最高,种-多度分布为对数级数分布,反映植物群落结构较单一,适合各种蝶类生存和繁衍的资源不足;天然次生林蝶类多样性指数、物种丰富度高于人工林,均匀度小于人工林,但前者种-多度分布为对数级数模型,后者为对数正态模型,说明在封山育林状态下,对森林植被组成进行适当合理的干扰,有利于森林的健康发展     

Quantitative magnetic resonance analysis and a morphometric predictive model reveal lean body mass changes in migrating Nearctic–Neotropical passerines

Most studies of lean mass dynamics in free-living passerine birds have focused on Old World species at geographical barriers where they are challenged to make the longest non-stop flight of their migration. We examined lean mass variation in New World passerines in an area where the distribution of stopover habitat does not require flights to exceed more than a few hours and most migrants stop flying well before fat stores near exhaustion. We used either quantitative magnetic resonance (QMR) analysis or a morphometric model to measure or estimate, respectively, the fat and lean body mass of migrants during stopovers in New York, USA. With these data, we examined (1) variance in total body mass explained by lean body mass, (2) hourly rates of fat and lean body mass change in single-capture birds, and (3) net changes in fat and lean mass in recaptured birds. Lean mass contributed to 50% of the variation in total body mass among white-throated sparrows Zonotrichia albicollis and hermit thrushes Catharus guttatus. Lean mass of refueling gray catbirds Dumetella carolinensis and white-throated sparrows, respectively, increased 1.123 and 0.320 g h⁻¹. Lean mass of ovenbirds Seiurus aurocapillus accounted for an estimated 33–40% of hourly gains in total body mass. On average 35% of the total mass gained among recaptured birds was lean mass. Substantial changes in passerine lean mass are not limited to times when birds are forced to make long, non-stop flights across barriers. Protein usage during migration is common across broad taxonomic groups, migration systems, and migration strategies.     

Migration strategy and pathogen risk: non‐breeding distribution drives malaria prevalence in migratory waders

Pathogen exposure has been suggested as one of the factors shaping the myriad of migration strategies observed in nature. Two hypotheses relate migration strategies to pathogen infection: the ‘avoiding the tropics hypothesis’ predicts that pathogen prevalence and transmission increase with decreasing non‐breeding (wintering) latitude, while the “habitat selection hypothesis” predicts lower pathogen prevalence in marine than in freshwater habitats. We tested these scarcely investigated hypotheses by screening wintering and resident wading shorebirds (Charadriiformes) for avian malaria blood parasites (Plasmodium and Haemoproteus spp.) along a latitudinal gradient in Australia. We sequenced infections to determine if wintering migrants share malaria parasites with local shorebird residents, and we combined prevalence results with published data in a global comparative analysis. Avian malaria prevalence in Australian waders was 3.56% and some parasite lineages were shared between wintering migrants and residents, suggesting active transmission at wintering sites. In the global dataset, avian malaria prevalence was highest during winter and increased with decreasing wintering latitude, after controlling for phylogeny. The latitudinal gradient was stronger for waders that use marine and freshwater habitats (marine + freshwater) than for marine‐restricted species. Marine + freshwater wader species also showed higher overall avian malaria parasite prevalence than marine‐restricted species. By combining datasets in a global comparative analysis, we provide empirical evidence that migratory waders avoiding the tropics during the non‐breeding season experience a decreased risk of malaria parasite infection. We also find global support for the hypothesis that marine‐restricted shorebirds experience lower parasite pressures than shorebirds that also use freshwater habitats. Our study indicates that pathogen transmission may be an important driver of site selection for non‐breeding migrants, a finding that contributes new knowledge to our understanding of how migration strategies evolve.