281 research outputs found
On the use of ultraviolet photography and ultraviolet wing patterns in butterfly morphology and taxonomy
In a series of feeding experiments we found that, depending on the larval food plant species or part of food plant ingested, individuals of the blue butterfly Polyommatus icarus (Lycaenidae) exhibit broad variation of wing patterns in the ultraviolet (UV) range of wavelengths which is invisible to humans. Such intraspecific variability in UV wing patterns has been underestimated thus far due to the rather demanding approach needed to study these patterns. We discuss methodological problems with the assessment of butterfly UV wing patterns by UV photography. Given proper standardization, UV photography is a suitable method to qualitatively assess UV wing patterns for possible use in morphology or systematics. Spectrophotometly should preferably be used as quantitative method when consideling UV wing patterns in a communication context. No higher value should be attached to UV wing patterns as compared to human visible wing patterns
The coming and going of Batesian mimicry in a Holarctic butterfly clade
A study using phylogenetic hypothesis testing, published in BMC Evolutionary Biology, suggests that non-mimetic forms of the North American white admiral butterfly evolved from a mimetic ancestor. This case might provide one of the first examples in which mimicry was gained and then lost again, emphasizing the evolutionary lability of Batesian mimicry
The Host Genera of Ant-Parasitic Lycaenidae Butterflies: A Review
Numerous butterfly species in the family Lycaenidae maintain myrmecophilous associations with trophobiotic ants, but only a minority of ant-associated butterflies are parasites of ants. Camponotus, Crematogaster, Myrmica, and Oecophylla are the most frequently parasitized ant genera. The distribution of ant-parasitic representatives of the Lycaenidae suggests that only Camponotus and Crematogaster have multiply been invaded as hosts by different independent butterfly lineages. A general linear model reveals that the number of associated nonparasitic lycaenid butterfly species is the single best predictor of the frequency of parasitic interactions to occur within an ant genus. Neither species richness of invaded ant genera nor their ecological prevalence or geographical distribution contributed significantly to that model. Some large and dominant ant genera, which comprise important visitors of ant-mutualistic lycaenids, have no (Formica, Dolichoderus) or very few ant-parasitic butterflies (Lasius, Polyrhachis) associated with them
Transporting Atlanta: The Mode of Mobility under Construction
The transportation crisis in Atlanta has attained epic proportions. Inconveniences and hardships created by too many automobiles and not enough alternatives for movement, have reached untenable levels. Getting at what lies beneath the asphalt, interrogating what drives the paving of America, along with the seemingly unstoppable space, energy, and money consumption that the current mode of mobility entails will perhaps allow for future decision-making that includes a more nuanced reading of the landscape. In an effort to understand these forces, I interrogate the creation, trajectories, and current positioning of three major Atlanta transportation projects: the Metropolitan Atlanta Rapid Transit Authority (MARTA), the bus and rail system that has been the backbone of metropolitan Atlantaâs public transportation system for the past 30 years; the Georgia Regional Transportation Authority (GRTA), which is the super-agency created in 1999 in an effort to address the air quality issues in the region; and the Beltline, an enormously popular current proposal to build a 22-mile loop of greenspace, transit, and other amenities around an inner loop of the city built on existing rail beds. This investigation engages a wide literature on race, space, and place; attendance at various meetings and relevant symposia; archival data; and in-depth interviews with 20 area transportation experts and interested parties. As race and regionalism are so central to understanding power and procedure in metro Atlanta, particular attention is given to racial and spatial practices. This research reveals the contest over issue framing between car-centered growth promoters, environmental (or green) actors, and social justice, or equity proponents and how the outcomes of this triumvirateâs competition results in regional transportation policies and procedures. The examination of the three instances; MARTA, GRTA, and the Beltline, give us an excellent window into the making of mobility in the region. INDEX WORDS: Transportation, Atlanta, Race and Regionalism, Mobility, GRTA, Beltline, MARTA
Does the DNA barcoding gap exist? â a case study in blue butterflies (Lepidoptera: Lycaenidae)
BACKGROUND: DNA barcoding, i.e. the use of a 648 bp section of the mitochondrial gene cytochrome c oxidase I, has recently been promoted as useful for the rapid identification and discovery of species. Its success is dependent either on the strength of the claim that interspecific variation exceeds intraspecific variation by one order of magnitude, thus establishing a "barcoding gap", or on the reciprocal monophyly of species. RESULTS: We present an analysis of intra- and interspecific variation in the butterfly family Lycaenidae which includes a well-sampled clade (genus Agrodiaetus) with a peculiar characteristic: most of its members are karyologically differentiated from each other which facilitates the recognition of species as reproductively isolated units even in allopatric populations. The analysis shows that there is an 18% overlap in the range of intra- and interspecific COI sequence divergence due to low interspecific divergence between many closely related species. In a Neighbour-Joining tree profile approach which does not depend on a barcoding gap, but on comprehensive sampling of taxa and the reciprocal monophyly of species, at least 16% of specimens with conspecific sequences in the profile were misidentified. This is due to paraphyly or polyphyly of conspecific DNA sequences probably caused by incomplete lineage sorting. CONCLUSION: Our results indicate that the "barcoding gap" is an artifact of insufficient sampling across taxa. Although DNA barcodes can help to identify and distinguish species, we advocate using them in combination with other data, since otherwise there would be a high probability that sequences are misidentified. Although high differences in DNA sequences can help to identify cryptic species, a high percentage of well-differentiated species has similar or even identical COI sequences and would be overlooked in an isolated DNA barcoding approach
Impact of inundation regime on wild bee assemblages and associated beeâflower networks
International audienceAbstractWild bee assemblages on flood-prone meadows were compared with those on rarely inundated sites along the river Danube in easternmost Lower Austria. We sampled flower-visiting bees on 32 meadows from April to August 2016. Although we recorded more bee individuals on rarely inundated meadows, total bee species richness was higher on regularly flooded meadows and we observed a stronger differentiation diversity of bees among annually flooded meadows. Three network metrics derived from a bipartite plantâbee interaction matrix were unaffected by flooding regime. We conclude that extreme floods, which sporadically affect the investigated habitats, may have a devastating effect on wild bee populations, but communities quickly recover. This resilience surely depends on recolonization from the surrounding landscape, which emphasizes the need to consider community dynamics in highly variable floodplain areas not only locally, but on a landscape scale
The ant associates of Lycaenidae butterfly caterpillars â revisited
Based on a global compilation of data on ant associates of 523 Lycaenidae species, a synthesis is attempted as to which ants participate in these interactions. Ants from 63 genera have thus far been observed as visitors of facultative myrmecophiles or as hosts of obligate myrmecophiles among the Lycaenidae. Over 98% of records come from nectarivorous and trophobiotic ants in just three subfamilies, viz. Formicinae, Myrmicinae and Dolichoderinae, with the genera Crematogaster and Camponotus occupying the top ranks. Accumulation analysis suggests that rather few ant genera remain to be added to the list of associates. The representation of ant genera as attendants of lycaenid immatures is related to their global species richness, but with some notable exceptions. Ants that form ecologically dominant, large, long-lived colonies are over-represented as hosts of obligate myrmecophiles. The taxonomic diversity of lycaenid-ant associations is highest in the Oriental and Australian region, and lowest in the Neotropical and Afrotropical region. Among tropical African lycaenids, this is due to two butterfly lineages (genus Lepidochrysops and subfamily Aphnaeinae) that have massively radiated in the Neogene, but mostly maintaining their general affiliations with either Camponotus or Crematogaster ants, respectively. Many tropical and subtropical lycaenids nowadays form associations also with invasive alien tramp ants, giving rise to novel mutualistic interactions
Faunal composition of geometrid moths changes with altitude in an Andean montane rain forest.
Abstract Aim The objective of this study was to describe and interpret the changes in faunal composition in the moth family Geometridae (Lepidoptera) along a small-scale elevational gradient in a tropical montane rain forest. This gradient was compared with a large-scale latitudinal gradient in Europe. Location Investigations were carried out in the province Zamora-Chinchipe in southern Ecuador along a gradient ranging from 1040 to 2677 m above sea level at twenty-two sites. Methods Moths were sampled with light-traps in three field periods in 1999 and 2000 and subsequently sorted and determined to species or morphospecies. Results We analysed 13,938 specimens representing 1010 species of geometrid moths. The proportional contribution of subtaxa to the local geometrid fauna changes along the elevational gradient at all systematic levels considered. While proportions of species of the subfamilies Ennominae, Sterrhinae and Geometrinae significantly decrease, the proportion of Larentiinae increases with increasing altitude. Changes also occur within the subfamilies Ennominae and Larentiinae. The host-plant specialist ennomine tribes Cassymini, Macariini and Palyadini completely vanish, and the proportion of the tribe Boarmiini decreases at high altitudes. In contrast, the remaining tribes (mostly comprising polyphagous species) either do not show proportional changes (Azelinini, Nacophorini, Nephodiini, Ourapterygini) or even increase (Caberini, ĂCratoptera groupĂ). Within Larentiinae, the species proportion of the genus Eois decreases, whereas concomitantly the proportion of Eupithecia increases. There is a remarkable similarity between the altitudinal patterns in Ecuador and those found along the latitudinal gradient in Europe. Main conclusions Species of the subfamily Larentiinae seem to be particularly welladapted to harsh environmental conditions, towards both high altitudes and latitudes. They might disproportionately profit from lower predation at higher altitudes. Many changes in the faunal composition can be explained by expected host-plant requirements of the species involved. Our results show that diversity estimates based on taxon ratios which are assumed to be constant must be regarded with caution because such ratios can change rapidly along environmental gradients. Keywords Geometridae, Larentiinae, Ennominae, elevational gradient, latitudinal gradient, taxon ratios, host-plant specialists, indicator taxa, biodiversity indicators. Resumen Objetivo La meta de este estudio era describir e interpretar los cambios y la composiciĂł n faunĂstica en la familia de mariposas Geometridae (Lepidoptera) a lo largo de un gradiente altitudinal de escala pequeñ a en un bosque de montañ a en los trĂł picos. Este gradiente fue comparado con un gradiente latitudinal de escala grande en Europa
Molecular simulation of thermosetting polymer hardening: reactive events enabled by controlled topology transfer
We present a quantum mechanical / molecular mechanics (QM/MM) to tackle
chemical reactions with substantial molecular reorganization. For this,
molecular dynamics simulations with smoothly switched interaction models are
used to suggest suitable product states, whilst a Monte Carlo algorithm is
employed to assess the reaction likeliness subject to energetic feasibility. As
a demonstrator, we study the cross-linking of bisphenol F diglycidyl ether
(BFDGE) and 4,6-diethyl-2-methylbenzene-1,3-diamine (DETDA). The modeling of
epoxy curing was supplemented by Differential Scanning Calorimetry (DSC)
measurements, which confirms the degrees of cross-linking as a function of
curing temperature. Likewise, the heat of formation and the mechanical
properties of the resulting thermosetting polymer are found to be in good
agreement with previous experiments.Comment: To be published in ACS Macromolecule
Elevational species richness gradients in a hyperdiverse insect taxon: a global meta-study on geometrid moths
AIMS: We aim to document elevational richness patterns of geometrid moths in a globally replicated, multi-gradient setting, and to test general hypotheses on environmental and spatial effects (i.e. productivity, temperature, precipitation, area, mid-domain effect and human habitat disturbance) on these richness patterns. LOCATION: Twenty-six elevational gradients world-wide (latitudes 28° S to 51° N). METHODS: We compiled field datasets on elevational gradients for geometrid moths, a lepidopteran family, and documented richness patterns across each gradient while accounting for local undersampling of richness. Environmental and spatial predictor variables as well as habitat disturbance were used to test various hypotheses. Our analyses comprised two pathways: univariate correlations within gradients, and multivariate modelling on pooled data after correcting for overall variation in richness among different gradients. RESULTS: The majority of gradients showed midpeak patterns of richness, irrespective of climate and geographical location. The exclusion of human-affected sampling plots did not change these patterns. Support for univariate main drivers of richness was generally low, although there was idiosyncratic support for particular predictors on single gradients. Multivariate models, in agreement with univariate results, provided the strongest support for an effect of area-integrated productivity, or alternatively for an elevational area effect. Temperature and the mid-domain effect received support as weaker, modulating covariates, while precipitation-related variables had no explanatory potential. MAIN CONCLUSIONS: Despite the predicted decreasing diversityâtemperature relationship in ectotherms, geometrid moths are similar to ants and salamanders as well as small mammals and ferns in having predominantly their highest diversity at mid-elevations. As in those comparative analyses, single or clear sets of drivers are elusive, but both productivity and area appear to be influential. More comparative elevational studies for various insect taxa are necessary for a more comprehensive understanding of elevational diversity and productivity
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