Interrelations Among Habitat Use, Behavior, and Flight-Related Morphology in Two Cooccurring Satyrine Butterflies, Maniola jurtina and Pyronia tithonus

Mobility, activity patterns, habitat use, and some morphological traits of two often cooccurring satyrine butterflies of grasslands—the meadow brown (Maniola jurtina) and the hedge brown (Pyronia tithonus)—were studied by a mark-release-recapture method at two sites. Additionally, someflight-related morphological traits of a series of collected females of P. tithonus were compared between recently colonized and permanent populations. The more active, but less mobile P. tithonus got faster wing damage than did M. jurtina and had more, and more symmetrically spread eyespots onthe wings. For both species, the microdistribution was affected by shelter, long vegetation, and nectar, but this was more pronounced in P. tithonus. It is hypothesized that P. tithonus may traverse the same landscape at a slower rate than M. jurtina.     

Spot distribution in the meadow brown butterfly, Maniola jurtina L. (Lepidoptera: Satyridae): South Welsh populations

Meadow brown butterflies, Maniola jurtina , were studied on Skokholm Island, off the Pembrokeshire coast, from 1976 to 1978 and at six other sites in south Wales from 1973 to 1977.
Daily survival of butterflies on Skokholm was estimated by capture-recapture data to be 0.70–0.84, but these values may be low because in the year of detailed study, 1976, dispersal rates between study sites were high and increased through the emergence period.
The butterflies were scored for the number and placing of the hind wing spots (Ford, 1975). Female populations in the east of our study area resembled English populations for they were unimodal at 0 spots. Spotting increased westwards until on Skokholm and the adjacent mainland the females caught were roughly equally likely to have 0, 1 or 2 spots. The Skokholm male populations had many 3-spotted individuals and so the mode of 2 in the spot-frequency distribution was less clear cut that in English populations. The trends in south Wales therefore resemble those found along the Cornish peninsula and on the Isles of Scilly. We suggest the increasingly maritime climate and the fragmentation of habitat on the coastal fringes of the species range are factors which may selectively favour butterflies with high flying and dispersal ability. Brakefield (1983) has offered evidence that more highly spotted meadow browns indeed have such an ability.     

Comparison of two independent scoring techniques for spot variation in Maniola jurtina (L.) and the consequences of some differences

Eight samples (total N = 298) of female meadow brown butterflies Maniola jurtina were scored independently by P. M. Brakefield and W. H. Dowdeswell for hindwing spot-number and spot-combination. Spot-size was measured by P.M.B. W.H.D scored 37% few spots overall than P.M.B. ( N = 554). This resulted in some marked differences in spot-frequency distributions. There was a rather narrow threshold of spot-size above which nearly all spots were scored by both of us and below which most spots were only scored by P.M.B. When the data of P.M.B. are transformed by excluding all spots below a threshold a close correspondence of spot-frequencies is found. Relative differences between samples tend to be maintained in the untransformed data. The consequences of the differences in scoring techniques are discussed.     

Microhabitat use and hindwing phenotype in Hipparchia semele (Lepidoptera, Satyrinae): thermoregulation and background matching

Abstract. 1. Microhabitat use and background matching by adult Hipparchia semele (L.) in a coastal sand dune site in south Wales were studied during the flight period of 1986.
2. Microhabitat use by both sexes is related to temperature and activity. When settling substrates are cool, typically during the early morning, most individuals are located on the warmest basking substrate, lichen patches. After a period of warming, males perch to locate mates on exposed areas of sand where there is a large field of view and where they are visually apparent. Egg-laying females tend to settle on lichen patches throughout the day.
3. Overall, females are maximally visually cryptic when settled on lichen patches with unexposed forewings. Male crypsis on lichen is less effective, but greater on most other substrates, than that of females. It is argued that individuals match lichen patches because this substrate is used when they are most liable to detection and capture by vertebrate predators. Male crypsis is probably a compromise between maximizing protection on lichen patches and requirements for resemblance to other substrates.
4. The underside hindwing phenotype does not match sand. Background matching to this substrate is probably not important because it tends to be used when individuals are active and can effectively use secondary defence mechanisms.
5. It is suggested that the apical eyespot and orange patch on the forewing underside have a dual role in secondary defence, acting as a startling and deflective device, being exposed by disturbed individuals and by those engaged in activities which may disrupt the visual crypsis afforded by the hindwing underside.     

Poly modal emergence of the tiger swallowtail, Papilio glaucus (Lepidoptera: Papilionidae): source of a false second generation in central New York State

Abstract. 1. The tiger swallowtail butterfly, Papilio glaucus (L.) (Lepidoptera: Papilionidae), is commonly assumed to have a bivoltine life cycle in central New York State and other parts of the northeastern United States. The seasonal abundance of adults in Tompkins County, New York, shows a bimodal pattern in some years, and a skewed unimodal pattern in others. We studied the incidence of diapause, the potential for successful development of two generations in the field, and the dates of adult emergence from overwintering pupae to determine whether these seasonal patterns are the result of bivoltinism.
2. Insects from Tompkins County, reared as larvae under 16L:8D photoperiod, uniformly enter pupal diapause.
3. Comparison of the heat units required for successful development of two generations with the heat units available in the field during 11 years shows that emergence of non-diapausing individuals would occur too late in the summer to contribute to the second peak of butterfly abundance. Offspring of non-diapausing individuals could only rarely complete development before the end of the growth season.
4. Diapausing offspring of butterflies collected in early June and late July differed sufficiently in dates of emergence to account for the field pattern of seasonal abundance.
5. Electrophoretic studies revealed no evidence of genetic isolation between early and late emerging butterflies.
6. These results suggest that polymodal emergence of diapausing insects can masquerade as a bivoltine life cycle.     

Spot variation in Maniola jurtina (L.) (Lepidoptera: Satyridae) in southern Portugal and a comparison with the Canary Islands

A sample of 2013 meadow brown butterflies, Maniola jurtina , was obtained in the Algarve, southern Portugal, on behalf of E.B. Ford, the founder of ecological genetics. Variation in the meadow brown occupied Ford's attention for more than 40 years. Ford died in 1988; most of his collection had earlier been destroyed, but the meadow browns remained and became available for analysis. The butterflies were scored for spotting characters on both fore- and hindwings. The population is homogeneous over the entire area of the Algarve and there is no conclusive evidence of a difference between the two years of collection (1986 and 1987). It is probably also homogeneous with southern Iberia in general, an area unique in the western Palaearctic range of the species as it is characterized by a high spot average in males and a low spot average in females. Algarve butterflies differ markedly from those of the Canary Islands, where there is considerable inter-island heterogeneity, supporting the view that the Canary Island populations did not originate from southern Iberia. In the Algarve, many females aestivate and by September there is an essentially all-female population. These are low-spotted and differ significantly from females active in May and June at the start of the annual (one generation) flight season.     

Species composition,abundance and emergence phenology of midges (Deiptera: Chironomidae) in a brown-water stream of West-Central Alberta,Canada

Sixteen floating, box type emergence traps, each covering 0.1 m², were placed along 150 m of a third-order stretch of the Bigoray River, a slow-flowing, vegetation-choked, brown-water muskeg stream. Effects of trap design, trap shading, length of sampling interval, and stream velocity on the number of midges caught was examined. Of the 112 species of Chironomidae caught, 32 species made up 90% of the catch and their emergence phenology is described in detail. There were more rare species than expected from Preston's lognormal distribution. Percentage of Bigoray species belonging to Tanypodinae, Orthocladiinae, Chironomini and Tanytarsini was 18%, 43%, 20%, and 19%, and was compared with 27 other studies on lotic chironomids. During the 140-day emergence period an average of 19.3 × 10³ chironomids emerged per square meter of stream. Based on changes in male:female ratios throughout a species emergence period, it was postulated that 30% of the Bigoray chironomid species were univoltine, 50% were bivoltine, and 20% were trivoltine.     

Interpopulation variability on embryo growth,seed dormancy break,and germination in the endangered Iberian daffodil Narcissus eugeniae (Amaryllidaceae)

The main goal of the study was to assess germination requirements in a threatened daffodil to elaborate a detailed protocol for plant production from seeds, a key tool for conservation. Experiments were carried out both in the laboratory and outdoor conditions. In Pseudonarcissi section, endemic Iberian species of Narcissus studied heretofore have different levels of morphophysiological dormancy (MPD). Embryo length, radicle emergence, and shoot emergence were analyzed to determine the level of MPD. Both interpopulational variability and seed storage duration were also studied. Mean embryo length in fresh seeds was 1.32 mm and the embryo had to grow until it reached at least 2.00 mm to germinate. Embryo growth occurs during warm stratification, after which the radicle emerges when temperatures go down. Seed dormancy was broken in the laboratory at 28/14°C in darkness followed by 15/4°C, but the germination percentage varies depending on the population. In outdoor conditions, seed dispersal occurs in June, the embryo grows during the summer and then the radicle emerges in autumn. The radicle system continues to grow during the winter months, but the shoot does not emerge until the beginning of the spring because it is physiologically dormant and requires a cold period to break dormancy. Early cold temperatures interrupt embryo growth and induce dormancy in seeds with an advanced embryo development. Seeds of N. eugeniae have deep simple epicotyl MPD. In addition, we found that embryo growth and germination were improved by seed storage duration.     

Trends and temperature response in the phenology of crops in Germany

The phenology of 78 agricultural and horticultural events from a national survey in Germany spanning the years 1951–2004 is examined. The majority of events are significantly earlier now than 53 years ago, with a mean advance of 1.1–1.3 days per decade. The mean trends for 'true phases', such as emergence and flowering, of annual and perennial crops are not significantly different, although more trends (78% vs. 46%) are significant for annual crops. We attempt to remove the influence of technological advance or altered farming practices on phenology by detrending the respective time series by linear regression of date (day number) on year. Subsequently, we estimate responses to mean monthly and seasonal temperature by correlation and regression in two ways; with and without removing the year trend first. Nearly all (97%) correlation coefficients are negative, suggesting earlier events in warmer years. Between 82% and 94% of the coefficients with seasonal spring and summer temperatures are significant. The conservative estimate (detrended) of mean temperature response against mean March–May temperature (−3.73 days °C⁻¹) is significantly less than the full estimate (−4.31 days °C⁻¹), the 'true' size of phenological temperature response may lie in between. Perennial crops exhibited a significantly higher temperature response to mean spring temperature than the annual crops.     

Thermal effects on the egg stage of four sciomyzids with reference to phenology and biocontrol potential

Abstract:  With the global economic cost of liver fluke estimated at US$2000 million annually, alternative sustainable control methods need to be considered. One such option is biological control using malacophagous sciomyzids (Dipt.,). The effect of a range of temperatures (14, 17, 20, 23 and 26°C) on the duration of the egg stage of Sepedon spinipes spinipes (Scopoli), Pherbina coryleti (Scopoli), Tetanocera ferruginea Fallén and Psacadina verbekei Rozkošný was assessed using thermostatically controlled waterbaths (16 h light : 8 h dark). In general, for all species, the mean and median egg incubation periods decreased as the temperature increased. Optimum growth temperatures for mass rearing purposes are highlighted for each species. The cryopreservation (−20°C) of newly oviposited eggs for the purpose of long-term storage was also assessed and possible reasons for the variability in the duration of the egg stage between the species in relation to their phenologies are discussed.     

The effects of host plant phenology on the demography and population dynamics of the leaf-mining moth, Cameraria hamadryadella (Lepidoptera: Gracillariidae)

Abstract.

• 1 We examined the effects of variation in the timing of spring leaf production and autumn leaf fall on the survival, mortality and abundance of Cameraria hamadryadella on Quercus alba and Q.macrocarpa.
• 2 We monitored and manipulated the timing of foliation on field and potted Q.alba trees and observed the abundance of C.hamadryadella on those trees. We also monitored and manipulated the timing of leaf fall on Q.alba and Q.macrocarpa trees in the field and observed its effects on survival, mortality and abundance of C.hamadryadella.
• 3 Variation in the timing of spring leaf production has no effect on C. hamudryadella abundance. However, a warm winter and spring in 1991 led to accelerated development and the imposition of a facultative third generation in one out of ten years of observation.
• 4 In 1989, leaves fell relatively early and leaf fall in the autumn accounted for more than 50% of the mortality of C.hamudryadella. in 1990 and 1991 leaves fell relatively late and leaf fall induced mortality was substantially reduced and overwinter survival was markedly increased.
• 5 The abundance of C.hamadryadella remained constant in the spring and summer of 1990 following the previous autumn's relatively early leaf fall, but increased by 10-fold in the spring of 1991 following the relatively late leaf fall of autumn 1990. The abundance of C.hamadryadella also increased 4-fold between the summer of 1991 and the spring of 1992 after another autumn of relatively late leaf fall. We attribute these increases in abundance in part to reduced mortality because of later leaf fall.
• 6 Variation in the timing of autumn leaf fall may be responsible for initiating outbreaks of C.hamadryadella.

     

Ecological, vertical and elevational distributions of Heteropsis (Lepidoptera, Satyrinae) in the rainforest of Masoala (NE Madagascar)

As part of a bioinventory in the Masoala National Park (Madagascar) ' Radeau des cimes 2001 ', molecular variation within the genus Heteropsis according to their ecological distribution was investigated from samples collected in November 2001. Two mitochondrial genes ( COII and cyt b ) were partially sequenced for 49 samples. The three analytical methods used (neighbour-joining, maximum parsimony and maximum likelihood) produced phylogenetic trees that show similar topologies. In spite of the lack of dense species sampling, the analyses of the trees show that three species ( Heteropsis strigula , Heteropsis undulans and Heteropsis maeva ) fall in a previously suggested clade and that three other species ( Heteropsis narcissus , Heteropsis uniformis and Heteropsis pauper) constitute a group less well-supported phylogenetically. In addition, our results could suggest in each group a parallel niche partitioning. The elevation of capture localities and the ecological origin are partially related to identification of these groups, whereas the vertical height above ground of capture do not seem to have obvious effect on the structuring of the groups.     

温度对双委夜蛾实验种群生长发育及繁殖的影响

【目的】双委夜蛾Athetis dissimilis(Hampson)是近几年在中国大陆新发现的农业害虫,与二点委夜蛾Athetis lepigone(Mschler)形态相似,危害特点相同。明确温度对其生长发育的影响,对该害虫的预测预报和有效防控具有重要的指导意义。【方法】在光周期16L∶8D,RH 70%±10%的实验室条件下,设置17,21,25,29和33℃5个恒定温度,饲喂人工饲料,研究温度对双委夜蛾发育历期、死亡率及繁殖的影响,并计算各虫态的发育起点温度和有效积温。【结果】在17~33℃范围内,双委夜蛾均可以完成整个世代,各虫态发育历期随温度的升高而缩短;17和21℃下,双委夜蛾幼虫有7个龄期,而25℃以上时幼虫只有6个龄期。25℃下双委夜蛾死亡率最低(21.00%),单雌产卵量最高(763.95粒)。整个世代的发育起点温度和有效积温分别为9.38℃和1 015.36日·度。雌雄虫寿命和产卵期随温度的升高逐渐缩短,且各温度下雌虫寿命均较雄虫长,性比(雄雌比)均在1.18~1.20之间。【结论】25℃是双委夜蛾实验种群生长发育和繁殖的适宜温度。     

Specializations and polyphagy of Plebejus argus (Lepidoptera: Lycaenidae) in North Wales

Abstract. 1. The polyphagous butterfly, Plebejus argus L., was found to have specialized requirements: eggs are laid along vegetation/bare ground margins, larvae specialize on tender meristematic and reproductive growth, larvae and pupae are tended by Lasius ants, and warm microclimates are favoured.
2. These requirements are met in early successional habitats within several bio topes. These habitats are locally distributed, as is P. argus.
3. Populations on limestone, heathland and mossland biotopes did not differ greatly in ecologies. Given a choice of foodplants in captivity, larvae from heathland and limestone did show slight differences in preference, selecting some of the hostplants they normally encounter in the wild. Regardless of biotope, all these larvae were plant taxa generalists (on three plant families), but specialists on plant parts.
4. The decline of P. argus in Britain is attributed to loss of biotopes and to declining traditional management of them. Fewer habitats are available, and the distances between them are greater than formerly. As some of these habitats are short lived, and P. argus rarely flies far, the butterfly's decline is a compound effect of reduced areas of habitat and inability to colonize them.     

世界砂藓属植物地理分布格局及其系统演化意义

以“Index Muscorum”中的20个藓类植物地理分布单位为分析区域,基于标本信息和相关文献,统计了世界砂藓属84种植物在20个地理单位的分布数据,应用除趋势对应分析法和三维空间图直观地展示了世界砂藓属植物的地理分布格局。发现世界砂藓属植物分布明显地分为南半球区和北半球区,并与岗瓦纳古陆和劳亚古陆有较好的对应性。南半球区包括Am.2,Am.3,Am.4,Am.5,Am.6,Afr.2,Afr.3,Afr.4,Austr.1,Austr.2,As.4和Ant.等12个地理单位;北半球区包括Am.1,Eur.,As.1,As.2,As.3,As.5,Afr.1和Oc.等8个地理单位。砂藓属中的无瘤类群在南、北半球分布广泛,而叶片细胞壁具瘤的Niphotrichum和Codriophorus亚属的种类主要分布在北半球。推测砂藓属植物的起源应早于联合古陆分裂以前,其祖先类群的叶片细胞表面光滑无瘤。     

Study of intrapopulational variability of duration and temperature norms of development of the linden bug Pyrrhocoris apterus (Heteroptera, Pyrrhocoridae)

The existence of significant variability in duration and temperature norms of development between families within insect populations has been shown for the first time. This variability is inferfamily and therefore has genetic ground. Revealed for the first time is the statistically significant positive correlation between the regression coefficient of the development rate for temperature and the temperature threshold for development of eggs and larvae from different families. The greater the slope of the regression line of the development rate for temperature, the higher the temperature threshold value in this particular family. These results demonstrate for the first time the existence of genetic co-variation between the regression coefficient and the temperature threshold within the insect populations. It is suggested that the source of the interpopulational and interspecies changes in the temperature reaction norms of the insect development might be the intrapopulational hereditary variability of the development duration, regression coefficient, and the development threshold, this variability being an object of natural selection. It was shown that in all studied families and populations the values of the linear regression coefficient of development rates for temperature in eggs of the linden bug Pyrrhocoris apterus were markedly and statistically significantly higher, while the temperature threshold values—lower as compared with the corresponding parameters in larvae. These results obviously are in contradiction with the concept of the “isomorphism of development rates” (Jarosik et al., 2002), according to which the development threshold for all life cycle stages of a species should be the same, whereas only slopes of the regression lines of the development rate for temperature can differ. For the first time the absence of genetic covariation has been shown between the temperature norms of development of different life cycle stages of the species—eggs and larvae. This means that the regression coefficient as well as the sum of the degree-days and the development threshold in eggs and larvae are inherited independently and therefore they can be independently changed in evolution in correspondence with specific environmental conditions, under which these life cycle stages take place.     

Effects of growth temperature and winter duration on leaf phenology of Erythronium japonicum,a forest spring geophyte

The effects of growth temperature and winter duration on the leaf phenology of Erythronium japonicum were examined in two experiments. Bulbs wintered in the field were cultivated at 10 and 20° C and the bulbs were cultivated at 15° C after chilling treatment at 3° C for 60 and 120 days and without chilling in winter. The plants cultivated at 20° C showed significantly earlier leaf emergence, a more rapid rate of leaf extension and shorter leaf longevity than those cultivated at 10° C. The decrease in the leaf longevity at 20° C resulted from the decreases in the durations of all of the developmental, mature, and senescent phases. The bulbs without chilling treatment did not sprout leaves and those with chilling treatment sprouted leaves. The increase in the length of chilling treatment from 60 to 120 days affected leaf phenology in same manner as the increase in the growth temperature from 10 to 20° C.     

Effect of temperature on development and survival in Delias nigrina (Fabricius) (Lepidoptera: Pieridae)

Abstract The effect of temperature on rate of development and survival of the immature stages of a subtropical population of the black jezebel, Delias nigrina , was studied under laboratory conditions at a range of constant temperatures. Mean developmental times from first-instar larva to adult varied from 29 days at 27°C to 52 days at 19°C; the development threshold temperature and thermal constant were estimated to be 9°C and 494 degree-days, respectively. Larval developmental rates reached physiological maximum at the higher temperatures tested (25−27°C). Pupal development, by contrast, was not affected in the same way as larvae by higher temperature. Survival of the immature stages varied inversely with temperature: survival was highest at 19°C and significantly reduced at 27°C. Mortality at the higher temperature was attributable mainly to final-instar larvae and pupae. These findings indicate that, compared with other tropical pierids that have been studied, D. nigrina has: (i) a comparatively low temperature threshold; (ii) a slow rate of development; and (iii) a poor tolerance to moderately high temperatures. Physiologically, these features are more characteristic of a temperate butterfly than a tropical one. This physiological response appears to be reflected by the temperate nature of the genus as a whole, which may be related to its period of origin and evolution during past climatic events.     

Morphology,temperature and photoperiodic responses in Audouinella botryocarpa (Harvey) Woelkerling (Acrochaetiaceae,Rhodophyta) from Ireland

Abstract

Audouinella botryocarpa is reported for the first time from the British Isles. On the west and south coasts of Ireland and in the Isle of Man it grows in the intertidal on wave-splashed limpet shells and rock surfaces. Populations examined monthly in Galway Bay formed monosporangia throughout the year and tetrasporangia from December to March and May but no gametangial plants were found. Plants isolated into culture from monospores formed monosporangia at daylengths of 8, 10, 12, 14 and 16 h at 6.5, 8, 10, 11 and 15°C; the same plants formed tetrasporangia at daylengths ≤10 h at 8, 10 and 11°C but not at 6.5 and 15°C. Spores isolated from these plants gave rise to further monosporangial plants that also formed tetrasporangia under inductive conditions. Night-breaks of 1 h in a 16 h night prevented tetrasporangial reproduction and a critical daylength of ～10 h was found at 10°C. British Isles Audouinella botryocarpa typically has 6 rounded or irregularly-shaped chloroplasts per cell, each of which has a single, centrally-placed pyrenoid. The chloroplasts grow together in mature cells, typically giving the appearance of a single plate-like chloroplast with 6 pyrenoids. The implications of these observations for the generic classification of acrochaetioid algae is discussed and it is concluded that chloroplast morphology, number and the presence or absence of pyrenoids may provide the basis for a future generic realignment of acrochaetioid algae.     

Physiology, morphology and phenology of seed dormancy break and germination in the endemic Iberian species Narcissus hispanicus (Amaryllidaceae)

Background and Aims

Only very few studies have been carried out on seed dormancy/germination in the large monocot genus Narcissus. A primary aim of this study was to determine the kind of seed dormancy in Narcissus hispanicus and relate the dormancy breaking and germination requirements to the field situation.

Methods

Embryo growth, radicle emergence and shoot growth were studied by subjecting seeds with and without an emerged radicle to different periods of warm, cold or warm plus cold in natural temperatures outdoors and under controlled laboratory conditions.

Key Results

Mean embryo length in fresh seeds was approx. 1·31 mm, and embryos had to grow to 2·21 mm before radicle emergence. Embryos grew to full size and seeds germinated (radicles emerged) when they were warm stratified for 90 d and then incubated at cool temperatures for 30 d. However, the embryos grew only a little and no seeds germinated when they were incubated at 9/5, 10 or 15/4 °C for 30 d following a moist cold pre-treatment at 5, 9/5 or 10 °C. In the natural habitat of N. hispanicus, seeds are dispersed in late May, the embryo elongates in autumn and radicles emerge (seeds germinate) in early November; however, if the seeds are exposed to low temperatures before embryo growth is completed, they re-enter dormancy (secondary dormancy). The shoot does not emerge until March, after germinated seeds are cold stratified in winter.

Conclusion

Seeds of N. hispanicus have deep simple epicotyl morphophysiological dormancy (MPD), with the dormancy formula C_1bB(root) – C₃(epicotyl). This is the first study on seeds with simple MPD to show that embryos in advanced stages of growth can re-enter dormancy (secondary dormancy).