Ambient Spring Research Articles

Improving building thermal comfort through passive design – An experimental analysis of phase change material 3D printed concrete

As the effects of climate change are felt around the world, it is important to consider more sustainable practices in every industry to reduce greenhouse gas emissions and preserve resources. Sustainable practices in the building sector and construction industry include incorporating passive design solutions into the building design and constructing with recycled materials. In this research the main passive design solution considered is thermal energy storage by latent heat capacity of phase change materials (PCMs). Construction with bricks is widely used in the developing world, allowing much potential for the use of recycled brick aggregate in construction composites. This research is the first of its kind on PCM inclusion by aggregate impregnation of recycled brick aggregate in 3D printed concrete (3DPC). Two cavity façade sections are 3D printed using two concrete mix designs - the first, in which 64% of the natural aggregate in the mix is replaced with recycled brick aggregate, and the second, adjusted from the first by an addition of PCM to the pores of the recycled brick aggregate by vacuum impregnation, creating concrete with a total average latent heat capacity of 7360 J/kg. These façade sections are used in four sets of thermal tests in Stellenbosch, South Africa. It is concluded that by latent heat storage, PCM delays heat transfer through the PCM-3DPC passive design façade section, significantly increasing the time that internal ambient temperatures remain within standardised ranges of thermal comfort, and reducing the maximum internal ambient temperatures by up to 3.9 °C. Minimal leakage of PCM is proven by effectiveness of the PCM in the PCM-3DPC façade section after five months of exposure to outdoor ambient spring and summer conditions.

Effects of Extracts Containing Metabolites of Different Cyanobacteria from an Ambient Spring (Central Europe) on Zooplankters Daphnia magna and Duckweed Spirodela polyrhiza

Toxic cyanobacterial blooms are a well-known problem in eutrophic water bodies, but cyanobacterial toxicity in ambient springs is unexplored. Therefore, we studied the toxin content and effects of two extracts obtained from epilithic and benthic microbial mats containing different algae and filamentous cyanobacteria, Phormidium breve and Oscillatoria limosa, respectively, on fresh biomass, number of roots, and pigment content in duckweed Spirodela polyrhiza and on survivorship of Daphnia magna (Cladocera). Mat samples, used to prepare extracts for bioassays, were collected in the anthropogenically transformed limnocrenic Górecko spring, located (50°31′08″ N and 22°57′10″ E) in the Roztocze region (Eastern Poland). It drains an abundant aquifer built with Cretaceous sediments. Neither anatoxin-a (ANTX) nor microcystins (MCs) were detected in the extracts using HPLC techniques; however, negative effects of the extracts on tested organisms were observed. The Phormidium extract contained concentrations of cyanobacterial metabolites a few times higher than the Oscillatoria extract. In general, both extracts affected plants in a dose-dependent manner; however, the Oscillatoria extract influenced pigment production without a clear trend. The highest concentrations of Phormidium extract (p < 0.05) significantly decreased the number of roots and the content of chlorophylls and carotenoids in S. polyrhiza. The Oscillatoria extract caused a statistically significant (p < 0.05) decrease in biomass and number of roots; however, it generally positively influenced the production of pigments. The extract containing O. limosa metabolites was more toxic to D. magna than the extract containing higher amounts of metabolites of P. breve. Cyanobacteria inhabiting temperate springs may negatively affect hydrobionts by producing secondary metabolites other than ANTX and MCs; however, the contribution of algae cannot be excluded. Extensive research on cyanobacteria in springs, their metabolites, and their effects on living organisms should be conducted.

Phenological responses of temperate and boreal trees to warming depend on ambient spring temperatures, leaf habit, and geographic range

Changes in plant phenology associated with climate change have been observed globally. What is poorly known is whether and how phenological responses to climate warming will differ from year to year, season to season, habitat to habitat, or species to species. Here, we present 5 y of phenological responses to experimental warming for 10 subboreal tree species. Research took place in the open-air B4WarmED experiment in Minnesota. The design is a two habitat (understory and open) × three warming treatments (ambient, +1.7 °C, +3.4 °C) factorial at two sites. Phenology was measured twice weekly during the growing seasons of 2009 through 2013. We found significant interannual variation in the effect of warming and differences among species in response to warming that relate to geographic origin and plant functional group. Moreover, responses to experimental temperature variation were similar to responses to natural temperature variation. Warming advanced the date of budburst more in early compared to late springs, suggesting that to simulate interannual variability in climate sensitivity of phenology, models should employ process-based or continuous development approaches. Differences among species in timing of budburst were also greater in early compared to late springs. Our results suggest that climate change-which will make most springs relatively "early"-could lead to a future with more variable phenology among years and among species, with consequences including greater risk of inappropriately early leafing and altered interactions among species.

Dual effects of reversed winter–spring temperatures on year‐to‐year variation in the recruitment of chub mackerel (Scomber japonicus)

AbstractTo clarify the effects of temperature on the recruitment of chub mackerel (Scomber japonicus) in the North Pacific, we investigated the influence of winter surface temperature (WST) on spawners at the time of maturity around the spawning grounds and the influence of ambient spring temperature on larvae using estimated temperature (ET) obtained from particle tracking experiments. We found a significant positive correlation between ET approximately 10 days following hatching and the recruitment per spawning stock biomass (RPS) after 2000. The closer (more meandering) the Kuroshio Current (KC) axis was in relation to the spawning ground, the higher (lower) the spring surface temperature and the higher (lower) RPS was in the spawning ground. In contrast, WST inside KC near the maturity/spawning ground was significantly negatively correlated with RPS. A significant negative correlation between the temperatures in winter and spring was detected in the area after 2000, when the conditions of the Pacific decadal oscillation index and the stability of the Kuroshio Extension were synchronous, indicating that KC shifted northward during this time. The reversed temperature pattern was consistent with the winter–spring movement of KC axis in the offshore direction and was correlated with the winter–spring difference in the intensity of the Aleutian low. These results suggest that the annual variation in chub mackerel recruitment after 2000 was strongly affected by the combined effects of ambient temperature because of the reversal of conditions that occurred between winter and spring around the maturity/spawning ground, which was related to the KC path.

Temporal photoperiod sensitivity and forcing requirements for budburst in temperate tree seedlings

Phenological responses to winter and spring warming in trees alter growing season length and can influence productivity. An improved mechanistic understanding of phenology, including temporal changes in budburst forcing requirements (BFR) and photoperiod sensitivity, could improve projections of phenological shifts and changes in tree species composition in response to climate warming. We investigated changes in BFR and photoperiod sensitivities at high temporal resolution from mid-winter to spring in seedlings of eight common deciduous and coniferous temperate tree species. Eight provenances of F. sylvatica, a dominant European species, also were included to examine variability in bud dormancy patterns within a species. Tree seedlings were over-wintered in a common garden and transferred weekly into climate chambers at forcing temperatures (+20°C) from December to April. Budburst was observed under 16 and 8h photoperiods. Across species, as chilling unit sums accumulated, BFR and photoperiod sensitivity decreased. Functions relating chilling and forcing unit sums explained ambient spring budburst accurately. BFR differed strongly among species, but not among provenances of F. sylvatica from similar latitudes. Overall, our results indicate that a precise tracking of BFR and photoperiod sensitivity helps explain species-specific differences in phenotypic sensitivities, which can improve species-specific projections of phenological responses to climate warming.

Natural haplotypes of FLM non-coding sequences fine-tune flowering time in ambient spring temperatures in Arabidopsis.

Cool ambient temperatures are major cues determining flowering time in spring. The mechanisms promoting or delaying flowering in response to ambient temperature changes are only beginning to be understood. In Arabidopsis thaliana, FLOWERING LOCUS M (FLM) regulates flowering in the ambient temperature range and FLM is transcribed and alternatively spliced in a temperature-dependent manner. We identify polymorphic promoter and intronic sequences required for FLM expression and splicing. In transgenic experiments covering 69% of the available sequence variation in two distinct sites, we show that variation in the abundance of the FLM-ß splice form strictly correlate (R2 = 0.94) with flowering time over an extended vegetative period. The FLM polymorphisms lead to changes in FLM expression (PRO2+) but may also affect FLM intron 1 splicing (INT6+). This information could serve to buffer the anticipated negative effects on agricultural systems and flowering that may occur during climate change.

Iningainema pulvinus gen nov., sp nov. (Cyanobacteria, Scytonemataceae) a new nodularin producer from Edgbaston Reserve, north-eastern Australia

A new nodularin producing benthic cyanobacterium Iningainema pulvinus gen nov., sp nov. was isolated from a freshwater ambient spring wetland in tropical, north-eastern Australia and characterised using combined morphological and phylogenetic attributes. It formed conspicuous irregularly spherical to discoid, blue-green to olive-green cyanobacterial colonies across the substratum of shallow pools. Morphologically Iningainema is most similar to Scytonematopsis Kiseleva and Scytonema Agardh ex Bornet & Flahault. All three genera have isopolar filaments enveloped by a firm, often layered and coloured sheath; false branching is typically geminate, less commonly singly. Phylogenetic analyses using partial 16S rRNA sequences of three clones of Iningainema pulvinus strain ES0614 showed that it formed a well-supported monophyletic clade. All three clones were 99.7–99.9% similar, however they shared less than 93.9% nucleotide similarity with other cyanobacterial sequences including putatively related taxa within the Scytonemataceae. Amplification of a fragment of the ndaF gene involved in nodularin biosynthesis from Iningainema pulvinus confirmed that it has this genetic determinant. Consistent with these results, analysis of two extracts from strain ES0614 by HPLC–MS/MS confirmed the presence of nodularin at concentrations of 796 and 1096μgg−1 dry weight. This is the third genus of cyanobacteria shown to produce the cyanotoxin nodularin and the first report of nodularin synthesis from the cyanobacterial family Scytonemataceae. These new findings may have implications for the aquatic biota at Edgbaston Reserve, a spring complex which has been identified as a priority conservation area in the central Australian arid and semiarid zones, based on patterns of endemicity.

Dynamics in cyanobacterial communities from a relatively stable environment in an urbanised area (ambient springs in Central Poland).

Ambient springs are often cited as an example of an ecosystem with stable environmental conditions. A static biotope fosters the development of constant communities with a stable qualitative and relatively stable quantitative structure. Two years of studying cyanobacteria in different microhabitats of the rheocrenic and limnocrenic ambient springs located in urban areas showed that there is a high degree of cyanobacterial diversity and spatial and seasonal dynamics in communities. Spatial heterogeneity in relation to the type of spring and the type of microhabitat is reflected not only by a change in the quantitative structure (the number of species and their biomass), but also by a change in the composition of species. Seasonal changes depended on the type of spring and the type of microhabitat, where weather conditions influenced the communities by different degrees. Cyanobacterial communities of limnocrenes were more diverse in terms of composition and biomass, but they revealed a low seasonal dynamic in contrast to the communities of rheocrenes. The classification of springs based on their environmental conditions revealed that some springs were similar. The resemblance stemmed from the origin of human impact, which was reflected to a high degree in changes in the natural hydrochemical conditions of the springs. For the purpose of understanding which environmental factors had the greatest influence on cyanobacterial communities, a BIO-ENV procedure was performed. The procedure revealed that of most importance was a group of ions not related to the nature of the spring environment - NH4+, NO2-, NO3-, and PO43-. The presence of these ions in groundwater was a result of direct and indirect human activity in the area of aquifers. The dynamics in communities in the studied springs were accelerated by human impact and weather conditions.

Molecular phylogeny and detailed morphological analysis of two freshwater Rhizoclonium strains from contrasting spring types in Egypt and Italy

Two Rhizoclonium strains thriving in contrasting spring types (slightly hot spring/ambient, shaded pool spring) and biogeographic areas (El-Farafra Oasis in the Western Desert of Egypt/River-Po Plain in Northern Italy) were studied in depth based on field and cultured material, bright-field and fluorescence microscopy, and phylogenetic molecular analyses (SSU and LSU rRNA gene sequences). This polyphasic approach revealed that the two Rh. strains clearly belonged to the Rhizoclonium clade but differed in some of their key diagnostic features. The Egyptian Rhizoclonium strain, isolated from the spring-fed (Ain El-Balad) agricultural ditch in El-Farafra Oasis, was described with the working name ‘Rhizoclonium sp. 10.6 μm from a desert, slightly-hot spring’ based on its smaller cell diameter, ecological and phylogenetic molecular traits compared to allied morphospecies. Moreover, it was highlighted that the L/D ratio can be more than 3.0 within this group. The Italian Rhizoclonium strain, collected from the Fontanile Valle Re-shaded, pool ambient spring (Emilia-Romagna Region), was virtually identical to other strains identified as Rh. hieroglyphicum from China and Japan, due to its highly supported congruence in morphological characteristics and phylogenetic position. This study provided the first partial LSU and SSU rRNA gene sequences for European Rh. hieroglyphicum based on available literature. Phenotypic plasticity of rhizoid formation was also observed in both Rhizoclonium strains studied using culturing approaching techniques. Our investigation also confirms that a lot of work with a variety of approaches is still needed to assess the ecological preferences, morphological plasticity, and phylogenetics of freshwater Rhizoclonium taxa worldwide.

Cyanobacteria in ambient springs

Although neglected for a long time by freshwater-ecology research, springs are very important habitats for biodiversity conservation. They are multiple ecotones, and are characterized by a remarkable variety of environmental conditions (e.g., from highly-shaded to UV exposed, from permanent discharge to intermittent flow, from still water to strong currents, from extremely-soft to carbonate-precipitating water, etc.). Moreover, springs are often amongst the last high-integrity, oligotrophic freshwater habitats in densely populated areas. Because of the high quality of their waters, the main impact affecting springs is capturing and water diversion. Climate-change driven reduction in precipitations in many areas is likely to determine an aggravation of this impact. It is thus important to document the rich and peculiar biodiversity of springs, also to establish reference conditions for bioassessment methods. Especially in non-acidic springs with running water, and coarse lithic substrata, cyanobacteria are often one of the most taxa-rich and abundant groups of photoautotrophs. The relatively-scarce information available in the literature is mostly referred to similar habitats, and not to spring habitats in the narrower sense. Papers dealing with the cyanobacteria of ambient springheads (=eucrenal) worldwide are still very rare. These were reviewed separating ambient springs in temperate and warm climate, and with special attention to key species, to cyanobacterial strategies allowing survival in oligotrophic headwaters (e.g., nitrogen fixation, phosphatases, anti-UV compounds, etc.), and to distribution patterns. The review also hopes to bolster new interest and research on this topic, and suggests some promising research directions.

Biogeography and relevant ecological drivers in spring habitats: A review on ostracods of the Western Palearctic

Springs are relevant environments from an ecological point of view. The microhabitat-mosaic structure of these ecotones often harbors high biodiversity. Due to the temperature stability of permanent springs and to the persistence over geological time scales of their aquifers, these environments may act as refugia and as potential speciation sites for aquatic fauna. In this study, we review the current knowledge on the diversity and distribution of ostracods associated with ambient springs in the Western Palearctic area, and on the ecological factors that have been reported to affect their occurrence. Literature mining revealed 37 papers, allowing to gather information on 92 ostracod taxa belonging to 31 genera, found in 612 springs out of a total of 743. More detailed information available from 20 studies carried out in the Central-Eastern Alps and Northern Apennines allowed us to conduct a focus study on a more restricted geographic area. Several species have very low frequency, occurring in just one or two springs. Rare or endemic species were frequent, whilst only one non-native species (Chlamydoteca incisa) was found. Species richness varied from 1 to 9, and it was greater in pool springs than in flowing springs and seepages. Correspondence analysis on the presence-absence data unveiled biogeographical patterns in spring ostracod community composition. The variation in community composition was partly organised along altitudinal, latitudinal, water-temperature, and conductivity gradients, and spring typologies affected assemblage structure as well. Springs are important areas for biodiversity conservation at the continental and regional scale. Nevertheless, relatively few investigations have dealt with the human impacts on springs and their biota, and conservation guidelines are largely missing.

Pattern of Stylet Penetration Activity byHomalodisca vitripennis(Hemiptera: Cicadellidae) Adults in Relation to Environmental Temperature and Light Conditions

Effects of ambient spring air temperature and light intensity on stylet penetration activities of the glassy-winged sharpshooter, Homalodisca vitripennis (Germar), were studied under field conditions by using an electrical penetration graph. Electrical penetration graph waveforms representing salivary sheath formation and searching (pathway phase), xylem contact (X waves), and ingestion of xylem fluid (waveform C) were analyzed. Previous research supported the concept that acquisition of Xylella fastidiosa, the Pierce's disease bacterium, occurs during ingestion, whereas inoculation occurs during xylem contact periods (X waves). Diel patterns of H. vitripennis stylet activity showed that, regardless of light condition, xylem ingestion occurred for the longest duration when temperature remained above the feeding threshold (10°C), and only occurred at temperatures below the threshold when ingestion was continued from a preceding, warmer time. Regression analysis indicated that mean waveform durations per insect (WDI) for combined stylet activities (pathway and ingestion) as well as X wave frequencies were significantly influenced by temperature, but there was no significant impact of light intensity or interaction between temperature and light intensity. The relationship between temperature and stylet activities in terms of WDI and X wave frequency was described using linear and nonlinear models. Validation of the nonlinear models indicated that they well predicted the WDIs for both ingestion and combined stylet activities, using temperature only as a single input. Overall, findings clearly demonstrate that temperature is an important factor that influences the H. vitripennis feeding behaviors responsible for transmission (acquisition and inoculation) of the Pierce's disease bacterium, with implications for vector ecology and management, as well as disease epidemiology.

Salinity tolerance as a potential driver of ecological speciation in amphipods (Gammarusspp.) from the northern Chihuahuan Desert

Ecological speciation is the process by which barriers to gene flow arise between populations as a result of ecologically based divergent selection. Environmental salinity has been identified as one of the most important ecological drivers influencing distribution, abundance, and species richness of aquatic organisms. Springs of the northern Chihuahuan Desert vary in salinity and are home to the Gammarus pecos (Crustacea:Amphipoda) species complex. We used field experiments to compare salinity tolerance among 9 amphipod populations from geographically discrete habitats differing in ambient salinities and to calculate salinity response distances among populations. Cluster analysis placed populations into 3 groups corresponding to low, medium, and high ambient salinities. Partial Mantel tests revealed significant positive correlations between salinity tolerance and habitat salinity after controlling for other variables, such as geographic distance and neutral genetic differences. Our results provide evidence that ecological speciation could be occurring among amphipod populations at different springs, as indicated by dissimilar physiological responses that are correlated with differences in ambient spring salinities. Gene flow is restricted among populations, the restriction is reinforced by dispersal barriers between springs, and selection might preserve variants that most effectively tolerate local salinity levels. Gammarus diversification in the northern Chihuahuan Desert is driven by vicariance and isolation, along with local selection and adaptation.

Recruitment of Heliozoa, rhizopods and rotifers from the sediments of an extremely acidic lake during spring and early summer

AbstractThe goal of this study was to investigate the recruitment of zooplankton from the littoral sediment of Lake 111, an acidic lake in north‐east Germany, in April (spring) and June (early summer), and its role in coupling the benthos and the pelagic. Maximum heliozoan and rhizopod recruitment occurred in early summer from sediment cores incubated at ambient water temperatures (20°C). Conversely, recruitment of the rotifer Cephalodella sp. was highest in spring at ambient spring temperatures of 12°C. A combination of passive and active recruitment processes is likely responsible. The seasonal abiotic and biotic sediment characteristics were relatively constant and therefore not likely responsible for the observed temporal recruitment pattern. The sediment water and carbon content ranged from 20 to 50% (mean = 29 ± 6% standard deviation) and 2–12% (mean = 5 ± 2% standard deviation), respectively. Similarly, there was little variation in the chlorophyll‐a (mean = 0.2 ± 0.2 µg Chl‐a g−1 dry weight ≡ 6.1 ± 3.9 mg Chl‐a m−2). The in situ sediment bacterial density (0.82 × 109 ± 0.26 × 109 g−1 dry weight ≡ 1.01 × 109 ± 0.34 × 109 cells cm−3) was high. In contrast, the abundance of zoobenthos and their resting stages was low (< 25 individuals cm−3, and mean of 90 ± 75 cysts cm−3, respectively), with no temporal pattern being observed. Temperature was the only abiotic factor influencing recruitment.This study suggests that, even in relatively young, chemically extreme lakes, the benthos can play an important role in whole lake microbial processes and zooplankton community composition. Such benthic repositories of resting stages potentially provide protection against adverse environmental changes.

On the feasibility of some photochemical reactions of iodide in seawater

Aerated solutions of potassium iodide in de-ionised water, of between 5–20% (w/v), were exposed to ambient spring sunlight to estimate the rate of photochemical production of molecular iodine from iodide and oxygen in seawater. This rate cannot be measured directly as other reactions, for example the reduction of molecular iodine by organic matter, interfere. Also, a parallel photo-oxidation, initiated by organic matter in real seawater, may also occur. The experiments yield a half-life for iodide in tropical surface waters of about 29 months suggesting that the reaction is insignificant. At this rate it will not compete effectively against the reduction of molecular iodine by organic matter, and hence molecular iodine should not appear. The experiments also consider the photo-oxidation by nitrate, and iodate, a combination of nitrite and oxygen, and eliminate significant interference by chloride, bromide and the phosphate buffer. The rate of photo-oxidation with each of the first three oxidations is found to be first order with respect to oxidant concentration. The variation of photo-oxidation rate with pH is also studied, with a brief investigation without conventional oxidant, where electron cage complexes still promote photo-oxidation. The photochemical action spectrum for these reactions in sunlight is shown to extend between 300 and 425 nm. The photo-oxidation of iodide by iodate is more interesting to marine chemistry as the photo-reduction of iodate. Nevertheless, the reduction-rate is judged to be several orders too low to be significant in seawater. The mechanism of the reactions are discussed and lessons drawn on the stability of potassium iodide solutions used in iodate analysis. The KI actinometer is recommended to those studying other photochemical systems activated by UV-A light as it is linear and very simple and reliable.

Are Ambient Spring and Summer Ozone Levels Associated with Daily Emergency Department Seizure Visits?

Are Ambient Spring and Summer Ozone Levels Associated with Daily Emergency Department Seizure Visits?

Siting, design and operational controls for snow disposal sites

The Municipality of Anchorage (MOA), at 61 degrees north latitude, ploughs and hauls snow from urban streets throughout the winter, incorporating grit and chloride applied to street surfaces for traffic safety. Hauled snow is stored at snow disposal facilities, where it melts at ambient spring temperatures. MOA studies performed from 1998 through 2001 show that disposal site melt processes can be manipulated, through site design and operation practices, to control chloride and turbidity in meltwater. An experimental passive "V-swale" pad configuration tested by MOA investigators reduced site meltwater turbidity by an order of magnitude (to about 50 NTU from the 500 NTU typical of more conventional planar pad geometry). The MOA has developed new siting, design and operational criteria for snow disposal facilities to conform to the tested V-swale pad configuration.

Population Characteristics and Activity Patterns of the Namaqualand Speckled Padloper (Homopus signatus signatus) in the Early Spring

Early spring population parameters and activity of wild Namaqualand speckled padlopers (Homopus signatus signatus) were monitored using mark-recapture and thread-trailing methods. Eighty-three tortoises were studied between 22 August and 22 September 2000. The maximum number of scute rings counted was 14, with females appearing to have longer lives than males. Tortoises were encountered on rock slabs, on a rocky hill slope, and frequented adjacent, gently sloping fields with many flowering plants. The frequent use of shallow concealed crevices as hiding places may be, in part, caused by greater availability of such refuges. Single specimens were usually found in refugia, but occasionally male-female pairs were observed. The shelter types identified (rock and spaces under shrubs) were rarely used for more than one night. Activity was unimodal. Activity area and daily movements were lower in H. s. signatus than in other tortoise species, possibly because of their smaller body size, cooler ambient spring temperatures during this study, a short measurement period, smaller habitat requirement of H. s. signatus, or some combination of the four.

Population Characteristics and Activity Patterns of the Namaqualand Speckled Padloper (Homopus signatus signatus) in the Early Spring

Early spring population parameters and activity of wild Namaqualand speckled padlopers (Homopus signatus signatus) were monitored using mark-recapture and thread-trailing methods. Eighty-three tortoises were studied between 22 August and 22 September 2000. The maximum number of scute rings counted was 14, with females appearing to have longer lives than males. Tortoises were encountered on rock slabs, on a rocky hill slope, and frequented adjacent, gently sloping fields with many flowering plants. The frequent use of shallow concealed crevices as hiding places may be, in part, caused by greater availability of such refuges. Single specimens were usually found in refugia, but occasionally male-female pairs were observed. The shelter types identified (rock and spaces under shrubs) were rarely used for more than one night. Activity was unimodal. Activity area and daily movements were lower in H. s. signatus than in other tortoise species, possibly because of their smaller body size, cooler ambient spring temperatures during this study, a short measurement period, smaller habitat requirement of H. s. signatus, or some combination of the four.

Climate and change in clines for melanism in the two–spot ladybird, Adalia bipunctata (Coleoptera: Coccinellidae)

The polymorphic two-spot ladybird, Adalia bipunctata, shows clinal variation in the frequency with which melanic and non-melanic morphs occur. Here we show that the clines in melanism in The Netherlands have changed over the past two decades: they have become shallower. This change has coincided with an increase in local ambient spring temperatures at most meteorological stations close to the sampling sites. The potential contribution of thermal melanism to the change in the shape of the clines is discussed.