Movement of the Apollo butterfly Parnassius apollo related to host plant and nectar plant patches

1. The movement of adults of the endangered Apollo butterfly, Parnassius apollo, was studied using mark–recapture data, within a population consisting of discrete patches of the species’ host plant (n = 43), which were segregated spatially from patches of the species’ main nectar plants (n = 14). 2. The Apollo routinely moved large distances (median 260 m, maximum 1840 m), and moved frequently between the two types of patches. Only 27% (28/105) of the recaptures were made on the same host plant patch as the release. 3. The population acts as a patchy population where the adults mix over the whole area, but successful reproduction can only take place in the discrete host plant patches. 4. Occurrence on a host plant patch was restricted by the area size of the host plant patch and the spatial configuration of nectar plant patches. Thus, although the Apollo is a good flyer, its movement over the patches is still constrained by the segregation of adult and larval resources.     

Suitability of different fluorescent powders for mass-marking the Chrysomelid, Diabrotica virgifera virgifera LeConte

Abstract:  The Western Corn Rootworm, Diabrotica virgifera virgifera LeConte (Col., Chrysomelidae), is an invasive alien pest of maize, Zea mays , in Europe. The suitability of 14 fluorescent powders for mass-marking the adults was studied in laboratory and in field cages. The visual discrimination between remaining spots of each colour on the beetles was investigated under ultraviolet (UV) light, as well as their retention time and the influences of those colours on the beetle survival and flight take-off response. The two best recognizable orange colours (i.e. of Radiant Colour and of Fiesta Colours Swada) were proposed for field experiments in first priority, followed by an orange and a yellow (both Magruder Colour), another yellow (Fiesta) and a pink (Radiant), as all did not affect beetle survival and flight take-off response and were recognizable under UV light for at least 10 days in the field. In contrast, the colours yellow and green (Radiant), red and blue (Magruder), yellow (Ciba Geigy) and pink (Fiesta) were unsuitable, because they either quickly disappeared from the beetles or adversely affected beetle survival or flight take-off response. For mass releases with differently marked beetles, only the use of a single orange colour together with a single yellow colour or the use of a pink colour together with a yellow colour can be used since few spots can clearly be discriminated from each other under UV light.     

What is the required minimum landscape size for dispersal studies?

Among small animals dispersal parameters are mainly obtained by traditional methods using population studies of marked individuals. Dispersal studies may underestimate the rate and distance of dispersal, and be biased because of aggregated habitat patches and a small study area. The probability of observing long distance dispersal events decreases with distance travelled by the organisms. In this study a new approach is presented to solve this methodological problem. An extensive mark-release-recapture programme was performed in an area of 81 km(2) in southern Sweden. To estimate the required size of the study area for adequate dispersal measures we examined the effect of study area size on dispersal distance using empirical data and a repeated subsampling procedure. In 2003 and 2004, two species of diurnal burnet moths (Zygaenidae) were studied to explore dispersal patterns. The longest confirmed dispersal distance was 5600 m and in total 100 dispersal events were found between habitat patches for the two species. The estimated dispersal distance was strongly affected by the size of the study area and the number of marked individuals. For areas less than 10 km(2) most of the dispersal events were undetected. Realistic estimates of dispersal distance require a study area of at least 50 km(2). To obtain adequate measures of dispersal, the marked population should be large, preferably over 500 recaptured individuals. This result was evident for the mean moved distance, mean dispersal distance and maximum dispersal distance. In general, traditional dispersal studies are performed in small study areas and based on few individuals and should therefore be interpreted with care. Adequate dispersal measures for insects obtained by radio-tracking and genetic estimates (gene flow) is still a challenge for the future.     

The influence of spatial scale on quantifying insect dispersal: an analysis of butterfly data

Abstract. 1. A linear relationship between mean movement distances recorded and the size of the study area was found in a comparison of five mark–release–recapture studies of the meadow brown butterfly.
2. The scale impact on mean butterfly movement distances was also apparent when comparing the results for different butterfly species reported in 21 mark–release–recapture studies.     

Movement of two grassland butterflies in the same habitat network: the role of adult resources and size of the study area

Abstract. 1.  Movement patterns of two butterfly species (meadow brown Maniola jurtina L. and scarce copper Lycaenae virgaureae L.) were studied in a 172 ha area within a landscape with a high percentage of suitable habitats for mark–release–recapture experiments.
2.  Adult resource density, but not patch size or larval food plant abundance, influenced the numbers and the fractions of residents, emigrants, and immigrants.
3.  Differences between species were observed in movement frequency and maximum distances moved but not in mean distances moved.
4.  The scarce copper showed much greater movement ability than expected from the results of published studies. This is believed to be a result of the comparatively large size of the study area and the high cover of suitable habitat (>50%).
5.  The mean and maximum distances travelled by butterflies reflected differences in the size of the study area.     

Contrasting movement patterns in two species of chequerspot butterflies, Euphydryas aurinia and Melitaea phoebe, in the same patch network

Abstract.  1. Mark–release–recapture studies were conducted on two species of chequerspot butterfly, Euphydryas aurinia and Melitaea phoebe , in the same habitat patch network in Yanjiaping, a small basin in the Taihang Mountains, north-west of Beijing, China, in 2000.
2. Euphydryas aurinia tended to stay in the habitat patches and to move to neighbouring patches, whereas M. phoebe moved widely among patches in the entire network.
3. The parameters of the virtual migration model showed higher daily emigration propensity in M. phoebe and in E. aurinia males than in E. aurinia females, and significantly greater average daily movement distance in M. phoebe than in E. aurinia .
4. The results are consistent with the previous findings showing genetic structuring among local populations of E. aurinia but not among local populations of M. phoebe .
5. Based on the genetic and ecological results, it was concluded that E. aurinia has a classic metapopulation in the study area, whereas M. phoebe appears to have a source–sink metapopulation.
6. In 2000, when there was an overall increase in the abundance of the two species, the limited mobility of E. aurinia resulted in an increase in the average local population size, whereas the increase in the number of local populations in M. phoebe was due to its high mobility .     

Within field movement of overwintered Colorado potato beetle: a patch-based approach

Abstract:  After comparing the persistence of four marking techniques, a mark–release–resight study was performed to characterize mid-season movement of the Colorado potato beetle [ Leptinotarsa decemlineata (Say); Col., Chrysomelidae] simultaneously in a fallow and in a wheat field. Isolated patches of potatoes were installed in a random spatial arrangement on both fields similarly. Overwintered beetles were individually marked and released. Beetles showed limited inter-patch movement activity (15.9% of recovery events) with an overall mean daily dispersal of 0.309 m (0.0–7 m). There was a significant difference in the insects' movement distance between the fallow and wheat field but there was no difference between the movement distances of males and females. The distance between the patches varied between 1 and 7.81 m, and inter-patch movement was infrequent (15.9%). Results suggest that surrounding fields by wheat rather than fallow grounds should be studied as a possible strategy to reduce the movement of overwintered beetles between potato fields.     

Effects of meadow suitability on female behaviour in the alpine butterfly Parnassius smintheus

Abstract  1. Many butterfly populations persist in networks of naturally fragmented habitat patches. Movement and reproductive decisions made by adult females are critical to the persistence of these populations because colonisation of extinct habitat patches in the network requires emigration of fecund adult females from their natal meadow and their subsequent establishment in the extinct patch.
2. Movement and oviposition behaviours of mated Parnassius smintheus females released in suitable meadows (a good- and a poor-quality meadow) and an unsuitable meadow were compared, to determine whether adult females consider meadow suitability for their offspring despite frequent oviposition events off the larval host plant.
3. Bootstrap and correlated random walk analyses of female step lengths and turn angles demonstrated that females flew more randomly in the unsuitable meadow than in the suitable meadows. Although females tended to turn the sharpest angle between landing sites in the good-quality meadow, and fly the smallest distance between landing sites and displace the smallest distance from the release site in the suitable meadows, no significant differences were detected in turn angle, step length, and dispersal rates between suitable and unsuitable meadows.
4. Results from female flight observations and a caged oviposition study suggest that females lay significantly more eggs in suitable habitat than in unsuitable habitat despite not ovipositing on the host plant, and support the above findings.
5. Movement and oviposition behaviours of adult female P. smintheus promote their retention within meadows that can support their offspring.     

Population sizes and dispersal pattern of tsetse flies: rolling on the river?

The West African trypanosomoses are mostly transmitted by riverine species of tsetse fly. In this study, we estimate the dispersal and population size of tsetse populations located along the Mouhoun river in Burkina Faso where tsetse habitats are experiencing increasing fragmentation caused by human encroachment. Dispersal estimated through direct (mark and recapture) and indirect (genetic isolation by distance) methods appeared consistent with one another. In these fragmented landscapes, tsetse flies displayed localized, small subpopulations with relatively short effective dispersal. We discuss how such information is crucial for designing optimal strategies for eliminating this threat. To estimate ecological parameters of wild animal populations, the genetic measures are both a cost- and time-effective alternative to mark–release–recapture. They can be applied to other vector-borne diseases of medical and/or economic importance.     

Evaluation of traps used to monitor southern pine beetle aerial populations and sex ratios

1 Various kinds of traps have been employed to monitor and forecast population trends of the southern pine beetle (Dendroctonus frontalis Zimmermann; Coleoptera: Scolytidae), but their accuracy in assessing pine‐beetle abundance and sex ratio in the field has not been evaluated directly. 2 In this study, we used fluorescent powder to mark pine beetles emerging from six isolated infestations. We then compared estimates of total abundances and proportions of males emerging from within each infestation to the estimates from three types of traps: passive sticky traps (2, 5, 10 and 20 m away from the source of beetles), multi‐funnel traps baited with pine beetle attractants (100 m away) and pine trees baited with attractants (also 100 m away). 3 We found that the proportion of males captured in traps was significantly affected by the type of trap used. 4 Within an infestation, equal proportions of males and females were marked (0.53 ± 0.02 males; mean ± SE), but the proportions captured in trap trees and passive traps were more female biased (0.42 ± 0.03 and 0.46 ± 0.01 males, respectively). On the other hand, funnel traps provided an estimate of the proportion of males that was nearly identical to the proportion from within infestations (0.51 ± 0.03). 5 Numbers of marked beetles captured in traps were uncorrelated with the numbers of marked beetles emerging from the focal infestations. This suggests that traps positioned around an infestation may not be effective at estimating relative abundances of beetles within the infestation.     

Response of Cydia pomonella to selection on mobility: laboratory evaluation and field verification

1. The codling moth Cydia pomonella (L.), largely regarded as a sedentary species, shows great variation in flight capacity among individuals in the laboratory, as has been reported for tethered flight. The occurrence of individuals with the ability to fly over long distances is considered ecologically significant for the colonisation of new habitats in response to deteriorating environmental conditions. The work reported here was designed to investigate the importance of the genetic component in regulating dispersal in C. pomonella. 2. Bi‐directional selection on mobility measured by actograph was carried out in the laboratory. Both male and female codling moths responded significantly to the upward and downward selections. Divergence between the two selected strains occurred after one generation of selection and increased as further selections continued. The realised heritabilities for mobility were estimated as 0.43 in males and 0.29 in females when averaged from the two selection directions. 3. The dispersal capacity of the selected mobile and sedentary strains was verified by mark–release–recapture experiments in the field, though only the released male moths were captured effectively. Flight distances by males differed significantly between the two strains, with the mobile strain showing a greater dispersal capacity than the sedentary strain. 4. This study demonstrated a positive correlation between mobility measured by actograph and field dispersal capacity in the codling moth. Furthermore, it provides the first experimental data to show field performances of different genotypes in insect dispersal.     

An experimental examination of the effects of habitat quality on the dispersal and local abundance of the butterfly Parnassius smintheus

Abstract 1. Nectar flower abundance was manipulated through flower removal, and sex ratio was manipulated by moving individual butterflies within a series of nine alpine meadows. The movement and abundance of the butterfly Parnassius smintheus in the meadows were monitored using mark–release–recapture methods.
2. A total of 937 butterflies, 698 males and 239 females, was captured. There were 223 observed between-meadow movements. Fifty-two per cent of males and 35% of females moved among meadows.
3. The immigration of male butterflies was related positively to nectar flowers, host plant abundance, and female butterflies. Male emigration was not affected by any of the treatments. The number of males captured was related positively to nectar flowers and host plants but not affected by sex ratio. The number of resident male butterflies was greater in meadows containing flowers and was related positively to host plant abundance, but unaffected by sex ratio.
4. Flower removal, sex ratio, and abundance of Sedum had no significant effect on the abundance, movement, or residence time for female butterflies, in part due to small sample size.
5. The fact that males immigrate to higher quality meadows suggests that male butterflies are assessing meadow quality, either by sampling meadows or potentially from a distance using olfactory cues.     

Ecological differentiation between the Sardinian endemic Maniola nurag and the pan-European M. jurtina

Recently refined evolutionary theories have highlighted that ecological interactions and environmental gradients can play a major role in speciation. This paper reports on a 3‐year field study, in which the ecology of two congeneric butterfly species was used to explore and compare the environmental factors determining their spatial distribution. These data are discussed in the context of possible speciation scenarios between the Sardinian populations of Maniola nurag and M. jurtina. M. nurag is endemic to the island of Sardinia, while M. jurtina is widespread over Europe. In Sardinia, the two species are locally sympatric. Mark–release–recapture experiments were combined with measures of environmental variables in 15 1‐ha plots, established in areas of potential habitat for the butterflies. Constrained linear models were parameterized from mark–recapture data to estimate both individual (survival and capture probabilities) and population (population size and recruitment) parameters. The two species had similar demography, movement patterns, life history, and behaviour. Population sizes developed in a parabolic fashion from beginning to end of the flight season. Differences included local population size, adult phenology, and habitat requirements. Long‐distance movements larger than 1.5 km were observed, suggesting a substantial amount of gene‐flow between populations of the endemic as well as the widespread species. Multivariate analyses revealed four main environmental gradients responsible for the abundance of the butterflies in an area. Both species responded similarly to environmental variables. However, each species’s abundance was correlated with a different environmental gradient determined by vegetation cover and structure. When sympatric, the two species responded to subtle differences in microhabitat structure. This might originally have induced their divergence. This study is an example of how empirical field data on population dynamics, dispersal, and habitat characteristics of two sympatric congeners can further our understanding of how species differentiate despite existing gene‐flow. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89 , 561–574.     

Dispersal of the Old World screw-worm fly Chrysomya bezziana

Abstract. Dispersal of the Old World screw-worm fly, Chrysomya bezziana Villeneuve, was studied in Papua New Guinea by releasing radio-isotope labelled, laboratory-reared flies and collecting their labelled egg masses from sentinel cattle. A log-linear model was developed to describe recapture rate. Distance was found to dominate the model and was represented by a bilinear ('broken-stick') term as log-distance. Further terms in the model such as attractiveness of the site (estimated from the number of non-labelled egg masses), the season of the year and a time trend were statistically significant but of minor importance. From the model, the median distance females dispersed before depositing an egg mass was 10.8 km. The maximum distance from the release site that egg masses were recovered was 100 km.
The dispersal ability of C. bezziana is discussed in terms of its impact on the prospects of eradicating this species using SIRM if an outbreak occurred in Australia.     

基于线粒体基因组控制区序列的中国冰清绢蝶遗传分化和谱系生物地理研究

【目的】分析中国冰清绢蝶Parnassius glacialis遗传多样性和遗传分化情况及其系统发生关系,推测其起源及分歧时间,并探讨其历史生物地理分布格局的成因。【方法】以2008-2016年采集于中国13个地区的冰清绢蝶的325头及绢蝶属其他11个种的11头个体样品,对其线粒体基因组的AT富集区(控制区)序列进行PCR扩增和序列测定,采用MEGA 6.0, Dna SP 5.1和Arlequin 3.5等软件分析其遗传多样性和遗传分化情况;以其他近缘绢蝶种类作为外类群,采用PhyML3.0, MrBayes 3.2和BEAST V1.8.3等软件重建冰清绢蝶的系统发生树,并利用宽松分子钟和校准方法推测中国冰清绢蝶的起源和分歧时间;同时结合现今冰清绢蝶的地理分布特点和第四纪以来的地球环境事件,分析其扩散路径,探讨其历史生物地理分布格局及成因。【结果】冰清绢蝶AT富集区序列长度介于487～495 bp之间,平均为491 bp,其长度的差异主要体现在Poly(T)或Poly(A)的数目差异,A+T平均含量为95.76%。供试冰清绢蝶13个地理居群325头个体中,共检测出基于线粒体基因组AT富集区序列的239个单倍型,单倍型多样性Hd为0.9971;核苷酸多态性指数π值为0.02948, Theta (per site)Eta值为0.06594。系统发生分析和分子定年显示,冰清绢蝶和白绢蝶P.stubbendorfii为近缘姊妹种,二者在距今7.52百万年(Ma)的中新世晚期开始分化。冰清绢蝶的祖先可能起源于我国西南地区(现今横断山脉-喜马拉雅附近的青藏高原东北缘)距今1.53 Ma的更新世时期,先由起源地先期扩散到达小陇山、秦岭一带;后来,由于第四纪的冰期-间冰期轮回事件和扩散路径的不同而分化出2大支系,但两个支系之间存在少量的单倍型相互混杂现象;随后,2大支系继续向低海拔、低纬度地区扩散,即通过伏牛山脉向东北方向扩散到嵩山、泰山、昆嵛山一带,经大别山系向东南方向扩散到琅琊山、紫金山和天目山一带。【结论】中国13个居群的冰清绢蝶没有形成明显的地理分化格局,其遗传变异主要来自居群内部,居群间的遗传分化现象尚不明显;冰清绢蝶起源于更新世时期的较高海拔地区,由于第四纪的冰期-间冰期轮回事件以及扩散路径的不同而形成2大支系并向中国东部和南部低海拔和低纬度地区扩散。     

Testing the role of ecological selection on colour pattern variation in the butterfly Parnassius clodius

Colour pattern has served as an important phenotype in understanding the process of natural selection, particularly in brightly coloured and variable species like butterflies. However, different selective forces operate on aspects of colour pattern, for example by favouring warning colours in eyespots or alternatively favoring investment in thermoregulatory properties of melanin. Additionally, genetic drift influences colour phenotypes, especially in populations undergoing population size change. Here, we investigated the relative roles of genetic drift and ecological selection in generating the phenotypic diversity of the butterfly Parnassius clodius. Genome‐wide patterns of single nucleotide polymorphism data show that P. clodius forms three population clusters, which experienced a period of population expansion following the last glacial maximum and have since remained relatively stable in size. After correcting for relatedness, morphological variation is best explained by climatic predictor variables, suggesting ecological selection generates trait variability. Solar radiation and precipitation are both negatively correlated with increasing total melanin in both sexes, supporting a thermoregulatory function of melanin. Similarly, wing size traits are significantly larger in warmer habitats for both sexes, supporting a Converse Bergmann Rule pattern. Bright red coloration is negatively correlated with temperature seasonality and solar radiation in males, and weakly associated with insectivorous avian predators in univariate models, providing mixed evidence that selection is linked to warning coloration and predator avoidance. Together, these results suggest that elements of butterfly wing phenotypes respond independently to different sources of selection and that thermoregulation is an important driver of phenotypic differentiation in Parnassian butterflies.     

以绢蝶为代表的甘肃南部蝶类多样性

在甘肃南部地区的蝶类调查中,共记录到蝴蝶339种,分属于12科,157属,区系组成以广布种为主,占总种数的56.6%;古北种次之,占26.9%;东洋种最少,占16.5%;共采集到绢蝶15种,占分布于中国绢蝶总种数41种的36.6%。样线调查结果显示绢蝶在甘肃南部地区有比较明显的垂直性分布,高山亚冰雪稀疏植被带、亚高山灌丛草甸带、山地森林草原带及山地草原带均有绢蝶分布。各生境中绢蝶多样性与蝶类群落多样性进行比对得出变化趋势不一致,随着海拔升高,绢蝶物种丰富度S及Shannon-Wiener多样性指数呈逐渐上升趋势,而蝶类群落物种丰富度S及Shannon-Wiener多样性指数总体呈下降趋势。绢蝶是高原地区的特有珍稀物种,君主绢蝶(P.imperator)、依帕绢蝶(P.epaphus)、小红珠绢蝶(P.nomion)等3种绢蝶为甘肃南部地区常见种,元首绢蝶(P.cephalus)等8种绢蝶为甘肃南部地区偶见种,数量极少,其种群及生存状态需予以关注。     

Reproductive asynchrony in natural butterfly populations and its consequences for female matelessness

1. Reproductive asynchrony, where individuals in a population are short-lived relative to the population-level reproductive period, has been identified recently as a theoretical mechanism of the Allee effect that could operate in diverse plant and insect species. The degree to which this effect impinges on the growth potential of natural populations is not yet well understood. 2. Building on previous models of reproductive timing, we develop a general framework that allows a detailed, quantitative examination of the reproductive potential lost to asynchrony in small natural populations. 3. Our framework includes a range of biologically plausible submodels that allow details of mating biology of different species to be incorporated into the basic reproductive timing model. 4. We tailor the parameter estimation methods of the full model (basic model plus mating biology submodels) to take full advantage of data from detailed field studies of two species of Parnassius butterflies whose mating status may be assessed easily in the field. 5. We demonstrate that for both species, a substantial portion of the female population (6.5-18.6%) is expected to die unmated. These analyses provide the first direct, quantitative evidence of female reproductive failure due to asynchrony in small natural populations, and suggest that reproductive asynchrony exerts a strong and largely unappreciated influence on the population dynamics of these butterflies and other species with similarly asynchronous reproductive phenology.