Dispersal Of Butterflies Research Articles

Good Things Come in Larger Packages: Size Matters for Adult Fruit-Feeding Butterfly Dispersal and Larval Diet Breadth

Introduction: In animals, body size is correlated with many aspects of natural history, such as life span, abundance, dispersal capacity and diet breadth. However, contrasting trends have been reported for the relationship between body size and these ecological traits. Methods: Fruit-feeding butterflies were used to investigate whether body size is correlated with species abundance, dispersal, permanence, and larval diet breadth in a Neotropical savanna in Brazil (Cerrado). We used Blomberg’s K and Phylogenetic Generalized Least Squares models (PGLS) to measure phylogenetic signal strength in species traits and to estimate size–dispersal–diet breadth associations, while also taking shared ancestry into account. Results: 539 individuals from 27 species were captured, and 190 individuals were recaptured, representing a 35% recapture rate. We found body size to be negatively associated with butterfly abundance, and positively associated with dispersal level, distance traveled, number of traps visited, individual permanence, and diet breadth. These results indicate that larger butterflies are more likely to disperse over longer distances. Moreover, larger butterflies have more generalized larval diets, based on the number of host plant families, genera, and phylogenetic diversity of the host plants they consume as larvae. Smaller butterflies rely on fewer resources, which is reflected in their higher survival in small patches and may explain their lower dispersal ability and higher diet specialization. Nevertheless, lower dispersal ability may, if not compensated by large population sizes, threaten small-bodied species inhabiting environments, such as the Cerrado, which have intense deforestation rates. Conclusions: Body size is positively associated with dispersal and diet breadth for the fruit-feeding butterflies collected in this study.

Sex-biased topography effects on butterfly dispersal

BackgroundMetapopulation persistence in fragmented landscapes is assured by dispersal of individuals between local populations. In this scenario the landscape topography, although usually neglected, may have an important role in shaping dispersal throughout the matrix separating habitat patches. Due to inter-sexual differences in optimal reproductive strategies, i.e., males maximizing the number of mating opportunities and females maximizing the offspring survival chances, topography-related constraints are expected to exert a different effect on male and female dispersal behaviour. We tested sex-biased topography effects on butterfly dispersal, with the following hypotheses: (1) females are constrained by topography in their movements and avoid hill crossing; (2) male dispersal is primarily driven by two-dimensional spatial structure of the habitat patches (i.e. their geometric locations and sizes) and little influenced by topography.MethodsFollowing intensive mark-recapture surveys of Maculinea (= Phengaris) nausithous and M. teleius within a landscape characterised by an alternation of hills and valleys, we investigated sex-specific patterns in their inter-patch movement probabilities derived with a multi-state recapture model. In particular, we (1) analysed the fit of dispersal kernels based on Euclidean (= straight line) vs. topography-based (= through valley) distances; (2) compared movement probabilities for the pairs of patches separated or not by topographic barriers; and (3) tested the differences in the downward and upward movement probabilities within the pairs of patches.ResultsEuclidean distances between patches proved to be a substantially stronger predictor of inter-patch movement probabilities in males, while inter-patch distances measured along valleys performed much better for females, indicating that the latter tend to predominantly follow valleys when dispersing. In addition, there were significantly lower probabilities of movements across hills in females, but not in males.ConclusionsBoth above results provide support for the hypothesis that topography restricts dispersal in females, but not in males. Since the two sexes contribute differently to metapopulation functioning, i.e., only female dispersal can result in successful (re)colonisations of vacant patches, the topography effects exerted on females should be considered with particular attention when landscape management and conservation actions are designed in order to maintain the functional connectivity of metapopulation systems.

Impacts of habitat on butterfly dispersal in tropical forests, parks and grassland patches embedded in an urban landscape

AbstractDispersal distances of 17 species of butterflies in tropical Singapore were significantly greater in forest than in urban habitat. Butterflies in urban plots frequently moved within suitable habitat (park/grassland) patches but rarely crossed non‐habitat patches suggesting potential isolation and a need for urban corridors.

Direct estimates of metapopulation capacity from dispersal show high interannual variability, but little effect of recent forest encroachment on network persistence

CONTEXT: Habitat loss and isolation are leading threats for biodiversity. Alpine habitat throughout the world is being lost and fragmented by forest encroachment. Previous analysis of forest encroachment from 1952 to 1993 in a population network along Jumpingpound Ridge, Alberta, Canada showed a 78% loss in meadow area, resulting in an estimated 41% reduction in dispersal of the alpine butterfly Parnassius smintheus. OBJECTIVES: Here, we pursue three questions. First, has forest encroachment continued since 1993? Second, if so, has it affected butterfly dispersal? And third, have any changes altered estimates of metapopulation persistence of this species? METHODS: The area of each meadow and distance between each pair of meadows were determined in GIS using aerial photographs taken in 1952, 1993, 1999, 2008, and 2012. Mark-recapture (1995–2015) and landscape data were used to estimate annual butterfly dispersal and network persistence. RESULTS: Alpine meadows along Jumpingpound Ridge continued to be fragmented by encroaching forest showing a decrease in area and increase in the amount of forest between them. Annual dispersal parameters varied over the study, but the only consistent response to forest encroachment was an increase in male dispersal distance within meadow habitat. Estimates of metapopulation capacity also varied greatly among years due to variability in dispersal. The network was predicted to persist based on nearly all estimates. CONCLUSIONS: Metapopulation capacity is a potentially powerful tool for conservation, but interannual variability in dispersal hampers its utility under realistic conditions and could result in erroneous conclusions regarding metapopulation persistence. The 7 km long network of 18 subpopulations of Parnassius smintheus along the Jumpingpound Ridge and Cox Hill is currently at little risk of extinction due to forest encroachment.

Weather explains high annual variation in butterfly dispersal.

Weather conditions fundamentally affect the activity of short-lived insects. Annual variation in weather is therefore likely to be an important determinant of their between-year variation in dispersal, but conclusive empirical studies are lacking. We studied whether the annual variation of dispersal can be explained by the flight season's weather conditions in a Clouded Apollo (Parnassius mnemosyne) metapopulation. This metapopulation was monitored using the mark-release-recapture method for 12 years. Dispersal was quantified for each monitoring year using three complementary measures: emigration rate (fraction of individuals moving between habitat patches), average residence time in the natal patch, and average distance moved. There was much variation both in dispersal and average weather conditions among the years. Weather variables significantly affected the three measures of dispersal and together with adjusting variables explained 79-91% of the variation observed in dispersal. Different weather variables became selected in the models explaining variation in three dispersal measures apparently because of the notable intercorrelations. In general, dispersal rate increased with increasing temperature, solar radiation, proportion of especially warm days, and butterfly density, and decreased with increasing cloudiness, rainfall, and wind speed. These results help to understand and model annually varying dispersal dynamics of species affected by global warming.

Butterfly dispersal in farmland: a replicated landscape genetics study on the meadow brown butterfly (Maniola jurtina)

Anthropogenic activities readily result in the fragmentation of habitats such that species persistence increasingly depends on their ability to disperse. However, landscape features that enhance or limit individual dispersal are often poorly understood. Landscape genetics has recently provided innovative solutions to evaluate landscape resistance to dispersal. We studied the dispersal of the common meadow brown butterfly, Maniola jurtina, in agricultural landscapes, using a replicated study design and rigorous statistical analyses. Based on existing behavioral and life history research, we hypothesized that the meadow brown would preferentially disperse through its preferred grassy habitats (meadows and road verges) and avoid dispersing through woodlands and the agricultural matrix. Samples were collected in 18 study landscapes of 5 × 5 km in three contrasting agricultural French regions. Using circuit theory, least cost path and transect-based methods, we analyzed the effect of the landscape on gene flow separately for each sex. Analysis of 1681 samples with 6 microsatellites loci revealed that landscape features weakly influence meadow brown butterfly gene flow. Gene flow in both sexes appeared to be weakly limited by forests and arable lands, whereas grasslands and grassy linear elements (road verges) were more likely to enhance gene flow. Our results are consistent with the hypothesis of greater dispersal through landscape elements that are most similar to suitable habitat. Our spatially replicated landscape genetics study allowed us to detect subtle landscape effects on butterfly gene flow, and these findings were reinforced by consistent results across analytical methods.

Mosaic of grasslands and woodlands is more effective than habitat connectivity to conserve butterflies in French farmland

In agricultural landscapes, permanent grassy habitats are often fragmented and partly composed of linear elements. Landscape-level connectivity of both grassland patches and grassy linear elements actively contributes to biodiversity conservation in farmland. Nevertheless, their respective importance has rarely been tested. Butterflies form a suitable model group for this purpose; they have suffered a major overall decline in the last few decades and are known to be sensitive to landscape connectivity.We sampled 286 transects nested in 18 study landscapes in three regions. Using several metrics, we analyzed the response of butterflies to the connectivity to both grassland and woodland habitats, which may provide additional resources. The response to landscape connectivity appeared to depend on the type of the semi-natural elements (patch vs linear elements), and on species traits, i.e. the response was stronger for habitat specialists and species with low dispersal ability. We found that woody habitats close to grassland patches had a significant positive effect on butterfly communities, denoting potential mechanisms of resources supplementation and complementation. In grassy linear elements, butterfly communities were of lower conservation value, richness and abundance were much lower (−26 and −50%) than in grassland patches and decreased with isolation from grasslands, in line with the source–sink hypothesis.Although grassy linear elements probably play an important role in butterfly dispersal in agricultural landscapes, they may not be sufficient to preserve specialist and sedentary species. Conserving a mosaic of high quality grassland patches and woody habitats appears more effective than enhancing connectivity.

Dispersal of butterflies in a New Guinea rainforest: using mark–recapture methods in a large, homogeneous habitat

In an intensive mark‐release‐recapture study of all butterfly species in a tropical rainforest understory, 5903 individuals from 90 butterfly species (from the estimated total of 104 ± 9 species present in understory habitat) were marked, and 1308 recaptured at least once. The study proved that mark‐recapture methods are feasible in tropical rainforests, but also showed its limitations, as after 232 person‐days of sampling we could only characterise dispersal for one‐third of the species present. The mean dispersal distance was 184 ± 46.1 m per species, while for six of the 14 species studied >1% of individuals were estimated to disperse 1 km or more. These parameters are, however, strongly dependent on the size and spatial configuration of the study plots, particularly in large homogeneous habitats. A new method proposed here to correct this bias revised the mean distance between two captures from 135 ± 33.6 to 325 ± 87.0 m per species. These results, in combination with data from large permanent rainforest plots, suggest that most woody plant species in tropical forests are sufficiently abundant to serve as host plant species even to monophagous Lepidoptera species.

Inter‐ and intra‐specific differences in butterfly behaviour at boundaries

AbstractTo plan effective conservation measures and to predict which species will be able to change distribution in response to climate change, there is an increasing need for understanding species dispersal abilities and how species move in complex landscapes. Responses to habitat boundaries affect emigration rates from habitat and are therefore important determinants of species dispersal. There are, however, few studies linking dispersal parameters to likelihood of crossing barriers across several species.In this study, dispersal and likelihood of crossing boundaries, which are presented here as tall and dense tree plantation, were investigated for seven butterfly species. Effects of adult age and sex on the dispersal and behaviour at boundaries were also analysed.Our results demonstrate differences in movements and response to habitat boundaries between species belonging to different butterfly families. Pieridae species were the most likely to cross boundaries and most mobile, whilst with the Lycaenidae species only a small fraction of individuals crossed the tall dense boundary.Individuals and species that moved with longer move bouts (i.e. steps) were more likely to cross boundaries. Therefore, we propose using step length, which is relatively easy to measure, as a proxy for butterfly dispersal at the landscape level.Female butterflies moved less than males within habitat but crossed boundaries more often than males, indicating that dispersal data needs to be collected for the two sexes separately to provide more accurate estimates of species ability to colonise new areas.

Effect of local weather on butterfly flight behaviour, movement, and colonization: significance for dispersal under climate change

Recent climate change is recognized as a main cause of shifts in geographical distributions of species. The impacts of climate change may be aggravated by habitat fragmentation, causing regional or large scale extinctions. However, we propose that climate change also may diminish the effects of fragmentation by enhancing flight behaviour and dispersal of ectothermic species like butterflies. We show that under weather conditions associated with anticipated climate change, behavioural components of dispersal of butterflies are enhanced, and colonization frequencies increase. In a field study, we recorded flight behaviour and mobility of four butterfly species: two habitat generalists (Coenonympha pamphilus; Maniola jurtina) and two specialists (Melitaea athalia; Plebejus argus), under different weather conditions. Flying bout duration generally increased with temperature and decreased with cloudiness. Proportion of time spent flying decreased with cloudiness. Net displacement generally increased with temperature. When butterflies fly longer, start flying more readily and fly over longer distances, we expect dispersal propensity to increase. Monitoring data showed that colonization frequencies moreover increased with temperature and radiation and decreased with cloudiness. Increased dispersal propensity at local scale might therefore lower the impact of habitat fragmentation on the distribution at a regional scale. Synergetic effects of climate change and habitat fragmentation on population dynamics and species distributions might therefore appear to be more complex than previously assumed.

Nymphalid butterfly dispersal among forest fragments at Serra da Canastra National Park, Brazil

Organisms must possess good dispersal ability to persist in fragmented landscapes, as extinction in habitat patches is frequent and patches must be re-colonised to keep viable metapopulations. Thus, metapopulation maintenance is dependent on patch size and distance, although these affect species differently. In order to evaluate the ability of Nymphalid butterfly species to live in naturally fragmented small forest fragments we marked and released 3,415 butterflies in 16 of these areas separated in two networks at the Serra da Canastra National Park (PNSC), south-eastern Brazil. Subsequent recaptures in different forest fragments enabled us to assess the dispersal rates and distances for several Nymphalid species. Seventeen butterflies from 11 out of the 50 species captured were directly observed to disperse from 500 m to 870 m. Dispersal rates varied between 1 and 7% of the marked individuals and were directly correlated to the mean forewing length of each butterfly species population. The connectivity of the forest fragments through creeks appear to facilitate butterfly dispersal among fragments within micro-basins, as only one out of 50 dispersing individuals was observed to fly from one micro-basin to the other. Several species had viable populations in the small-fragment network. The distance between fragments is crucial as the coarser fragment network was unlikely to sustain viable populations of most of the species. The protection of large forest fragments located outside of the PNSC may be necessary to promote colonization of the smaller forest fragments inside the Park.

Effects of Patch Size and Type of Coffee Matrix on Ithomiine Butterfly Diversity and Dispersal in Cloud‐Forest Fragments

Determining the permeability of different types of landscape matrices to animal movement is essential for conserving populations in fragmented landscapes. We evaluated the effects of habitat patch size and matrix type on diversity, isolation, and dispersal of ithomiine butterflies in forest fragments surrounded by coffee agroecosystems in the Colombian Andes. Because ithomiines prefer a shaded understory, we expected the highest diversity and abundance in large fragments surrounded by shade coffee and the lowest in small fragments surrounded by sun coffee. We also thought shade coffee would favor butterfly dispersal and immigration into forest patches. We marked 9675 butterflies of 39 species in 12 forest patches over a year. Microclimate conditions were more similar to the forest interior in the shade-coffee matrix than in the sun-coffee matrix, but patch size and matrix type did not affect species richness and abundance in forest fragments. Furthermore, age structure and temporal recruitment patterns of the butterfly community were similar in all fragments, independent of patch size or matrix type. There were no differences in the numbers of butterflies flying in the matrices at two distances from the forest patch, but their behavior differed. Flight in the sun-coffee matrix was rapid and directional, whereas butterflies in shade-coffee matrix flew slowly. Seven out of 130 recaptured butterflies immigrated into patches in the shade-coffee matrix, and one immigrated into a patch surrounded by sun coffee. Although the shade-coffee matrix facilitated movement in the landscape, sun-coffee matrix was not impermeable to butterflies. Ithomiines exhibited behavioral plasticity in habitat use and high mobility. These traits favor their persistence in heterogeneous landscapes, opening opportunities for their conservation. Understanding the dynamics and resource requirements of different organisms in rural landscapes is critical for identifying management options that address both animals' and farmers' needs.

Evaluating hypotheses about dispersal in a vulnerable butterfly

AbstractSound management of species requires reliable estimates of dispersal. Indeed, dispersal of individuals among local populations is a key factor in the biology and persistence of local populations and metapopulations. Here, the small‐scale dispersal pattern of a vulnerable species, the endemic Sardinian chalk hill blue butterfly, was studied by applying capture–recapture multistate models and a model selection based on AIC values. Model parameters were survival, capture and movement probabilities. The model selection showed that (a) survival probability of individuals varied between sexes, (b) capture probability varied between sexes and among patches, and (c) movement probability varied with direction. The probability of movement among adjacent local populations was generally low and ranged from 0.009 to 0.212. Movement probabilities were subsequently modeled using data on interpatch distance and donor patch population size or area. The ultrastructural “biology‐based” models turned out to be the most appropriate models for inference, showing that dispersal decreases with increasing interpatch distance and increasing donor patch population size or area, and suggesting that butterfly dispersal is affected by patch geometry and the presence of conspecifics. The application of multistate models, the model selection approach, and ultrastructural modeling allowed testing the validity of some general hypotheses related to dispersal in metapopulations and helped elucidate the butterfly small‐scale dispersal pattern.

The Butterflies of Pohnpei, Eastern Caroline Islands, Micronesia

Fourteen species of butterflies are recorded from Pohnpei, Micronesia, seven for the first time. None is endemic to the island; all are widely distributed in the western Pacific, including parts of Indo-Australia, with many extending into or beyond southeastern Asia. A long history of plant introductions and agricultural experimentation may have facilitated dispersal of butterflies to the island and provided a broad selection of host plants for those arriving otherwise unassisted. At least one, and possibly two or more, unidentified species apparently confined to deep forest habitats were seen but not collected during this study. Compared with the local odonate fauna, the butterflies of Pohnpei differ in reaching their greatest abundance and species diversity in the lowlands, in lacking endemic species, and probably in having a higher turnover rate.

Host Plant Phenology and Butterfly Dispersal: Causes and Consequences of Uphill Movement

In the Wenatchee Mountains of central Washington State, populations of the lycaenid butterfly Euphilotes enoptes occur patchily with their sole host plant, Eriogonum compositum (Polygonaceae). Nearly all courtship and adult feeding occur on the inflorescences of this long-lived perennial. Furthermore, because females oviposit on inflorescences and larvae feed only on flowers and developing seeds, the window of opportunity for exploiting this resource is narrow. I demonstrated that inflorescence phenology varied according to the aspect and elevation of plant patches, and butterflies were most likely to occur in patches nearing full bloom. A mark–release–recapture study revealed that individual butterflies can disperse far enough to sample from a wide range of patch phenologies, and the movements of females are apparently influenced by those phenologies. In particular, an uphill bias in female movement appeared to be the result of greater emigration from senescing low-elevation patches than from phenologically delayed, high-elevation patches. Males showed no such uphill movement. The apparent result of the uphill movement by females was that larval densities increased fourfold over a 300-m elevational gradient in each of two years. Differential mortality is an unlikely explanation for this variation in larval density, as both parasitism rates and frequency of visitation by ants, which tend larvae, did not vary with elevation. To demonstrate the influence of host plant phenology on adult behavior, I manipulated flowering phenology in an artificially established grid of small host plant patches and observed the encounters of adult butterflies with those patches. Inflorescences in patches that were nearing full bloom received disproportionately many visits by females, indicating that patches in this phenological state were more attractive to females. Small sample sizes prevented me from determining if this result was due to increased entry into those patches by females, an increased number of inflorescence visitations per female, or both. The frequency with which inflorescences in the different patches were visited by males did not vary with patch phenology. These results suggest that the uphill bias in dispersal by females is indeed a response to host plant phenology. Thus, in this system, among-patch variation in host plant phenology apparently influences the relative densities of larvae in different host plant patches by altering patterns of dispersal among those patches.

Community Characteristics and Vegetation Management of Karner Blue Butterfly (Lycaeides melissa samuelis) Habitats on Rights-of-Way in East- Central New York, USA

Lupinus perennis L. (blue lupine) and associated nectar species represent critical habitat for the endangered, federally listed Lycaeides melissa samuelis Nabokov (Karner blue butterfly), and exist on transmission line rights-of-way in New York, USA. While rights-of-way provide habitat and may represent a potential corridor for butterfly dispersal among sites, few data are available to quantify habitat characteristics. We investigated rights-of-way in east-central New York to: characterize L. perennis populations and associated plant communities; quantify the relationship between L. perennis and both environmental characteristics and management schemes; and assess the relationship between butterfly population size and habitat characteristics. Lupinus perennis individuals were robust in communities with Comptonia peregrina, species in the Poaceae, and Daucus carota. Lupinus perennis and L. m. samuelis abundance were correlated positively with high relative light intensity and large patch areas, and inversely correlated with the number of years since the last management activity. There was no clear relationship between vegetation patterns and the different types of recent rights-of-way vegetation management schemes. To enhance L. perennis and L, m. samuelis populations, vegetation management on rights-of-way should reduce trees and shrubs, and increase light intensity to a level of photosynthetically active radiation that exceeds 65% of the maximum possible light intensity. Other manageable conditions associated with a larger index of L. m. samuelis population size include larger habitat areas and more frequent vegetation management that reduces the cover and density of woody species. The relationship between both L. perennis clump size and L. m. samuelis population size with the distance to the warm edge of the right-of-way suggests a potential influence of microclimate and merits further attention. Vegetation management based on infrequent mechanical removal of woody stems (e.g. handcutting, mowing, brush-hogging) was associated with increased woody plant density. A more frequent mechanical treatment or a seasonally timed application of an appropriate herbicide would be more effective at controlling the woody vegetation that competes with L. perennis.

The effect of ant association on the population genetics of the Australian butterfly Jalmenus evagoras (Lepidoptera: Lycaenidae)

Populations of the myrmecophilous lycaenid Jalmenus evagoras Donovan were assessed for genetic structure at three hierarchical spatial scales: sites, geographically-defined subpopulations, and subpopulations defined by species of mutualistic ant-associate. Estimates of Wright's FST generated from multilocus electrophoretic data revealed low, though significant, amounts of genetic structure. Most structure was observed at the level of geographic subpopulations, suggesting that adult butterflies do not exhibit preferential mating and oviposition along the lines of ant associate. The genetic structure data, together with estimates of Nei's genetic distance (D) for pairwise site and subpopulation comparisons, suggest that J. evagoras populations are spatially and temporally dynamic. These patterns are considered in the context of extinction and recolonization models. The extreme patchiness of J. evagoras populations stems from the stringent requirements of both host plant and host ant, contributing to an extinction/ recolonization process. We discuss the key parameters influencing genetic cohesion versus differentiation under an extinction/recolonization regime, including mode of butterfly dispersal, site turnover rate, and the effects of host dispersal and phenology. This system provides a model of population-level consequences of certain mutualistic interactions as well as of a class of patterns arising from an extinction/recolonization process.

Reproductive Behavior in an Overwintering Aggregation of Monarch Butterflies

Mating is an important part of the daily activities of monarch butterflies in late winter in southern California. Mating activity increased steadily from late January 1972 until late February 1972. During the final week of February this activity decreased, coincident with the dispersal of butterflies from their clustering areas. Prior to mating, males pursue, capture and overcome resistance by female butterflies. In flights of mated pairs only males flap their wings. In overwintering areas male monarchs apparently do not signal females as reported for other danaid butterflies. Males frequently pursue and attempt copulation with other males; but since they more frequently pursue and canture females, they are evidently able to discriminate between the sexes. Females disapTear from the clustering sites earlier than males and shortly thereafter deposit eggs on local milkweed.

Dispersal of Butterflies and other Insects

THE letter of Mr. Robert Adkin in the issue of NATURE of September 26, on the vertical upward flight of moths from the Downs near Walmer, supplies one of the desiderata required to confirm the view indicated in Mr. Felt's article in NATURE of September 5 that the upper air-currents may play an important part in the distribution of flying insects. I have myself long expected that the dispersal of insects would ultimately attract the attention of the meteorologist, and Dr. Simpson's British Association address, which immediately precedes Mr. Felt's article, reads appositely beside Mr. Felt's appeal for the aid of convectional currents arising from heated surfaces in assisting insects to gain the upper air-strata. But in this connexion we must not forget that mountaineers have long exercised their brains over the problem of insects on high mountain tops. Whymper in particular, in his work on the equatorial Andes, dealt with this subject, and he quotes Humboldt and Bonpland as showing that insects are transported into the upper regions of the atmosphere (16,000 to 19,000 feet), and adds that the transportation of insects by ascending air-currents has occasionally been observed in operation. One such set of observations is noted by Mr. Felt when he writes, “Collectors on some of the high mountains, such as Mount Washington, have taken insects which are distinctly southern or south-western in habitat, probably carried there by the upper air-currents and dropped upon these cooler mountain tops”.

Dispersal of Butterflies and other Insects

IN the issue of NATURE for September 5, Mr. E. P. Felt in his interesting article on the “Dispersal of Butter flies and other Insects” says, “It is quite possible that some insect movements are direct responses to a migration impulse”. As bearing on this point, the following incident, which occurred some years ago, may not be without interest.