Summary
We assessed the influence of agricultural land use on aquatic–terrestrial linkages along streams arising from changes in the emergence of aquatic insects. We expected that terrestrial ...predators would respond to a change in the abundance and/or the size structure of the emerging aquatic insects by an increase or decrease in population size.
We measured the flux of emergent aquatic insects and the abundance of terrestrial invertebrate predators and birds along 10 streams across a forest‐to‐agriculture land‐use gradient. We also performed stable isotope analyses (hydrogen, carbon and nitrogen) of terrestrial invertebrate predators.
Small aquatic insects (Nematocera) were most abundant under agricultural land use, whereas larger bodied aquatic insects (Plecoptera and Trichoptera) were more associated with forest land use. Carabid beetles and linyphiid spiders were associated with agricultural streams (where there was a high abundance of small aquatic insects), whereas lycosid spiders and birds were associated with forest streams and a high abundance of large‐sized aquatic insects.
The contribution of aquatic insects to the diets of riparian Lycosidae, Linyphiidae and Carabidae was estimated to be 44%, 60% and 43%, respectively, indicating the importance of aquatic subsidies to the terrestrial system.
Our results show that agricultural land use in an overall forested landscape can have significant effects on the abundance and diet of terrestrial consumers through its impact on the size structure of the assemblage of emerging insects, rather than the overall magnitude (numbers) of the aquatic subsidy. Hence, our results suggest that the composition, not just quantity, of a cross‐habitat resource may influence the recipient system.
Mayflies, stoneflies and caddisflies (Ephemeroptera, Plecoptera and Trichoptera) are prominent representatives of aquatic macroinvertebrates, commonly used as indicator organisms for water quality ...and ecosystem assessments. However, unambiguous morphological identification of EPT species, especially their immature life stages, is a challenging, yet fundamental task. A comprehensive DNA barcode library based upon taxonomically well-curated specimens is needed to overcome the problematic identification. Once available, this library will support the implementation of fast, cost-efficient and reliable DNA-based identifications and assessments of ecological status. This study represents a major step towards a DNA barcode reference library as it covers for two-thirds of Germany's EPT species including 2,613 individuals belonging to 363 identified species. As such, it provides coverage for 38 of 44 families (86%) and practically all major bioindicator species. DNA barcode compliant sequences (≥500 bp) were recovered from 98.74% of the analysed specimens. Whereas most species (325, i.e., 89.53%) were unambiguously assigned to a single Barcode Index Number (BIN) by its COI sequence, 38 species (18 Ephemeroptera, nine Plecoptera and 11 Trichoptera) were assigned to a total of 89 BINs. Most of these additional BINs formed nearest neighbour clusters, reflecting the discrimination of geographical subclades of a currently recognized species. BIN sharing was uncommon, involving only two species pairs of Ephemeroptera. Interestingly, both maximum pairwise and nearest neighbour distances were substantially higher for Ephemeroptera compared to Plecoptera and Trichoptera, possibly indicating older speciation events, stronger positive selection or faster rate of molecular evolution.
Metabarcoding is a powerful, increasingly popular tool for biodiversity assessment, but it still suffers from some drawbacks (specimen destruction, separation, and size sorting). In the present ...study, we tested a non-destructive protocol that excludes any sample sorting, where the ethanol used for sample preserving is filtered and DNA is extracted from the filter for subsequent DNA metabarcoding. When tested on macroinvertebrate mock communities, the method was widely successful but was unable to reliably detect mollusc taxa. Three different protocols (no treatment, shaking, and freezing) were successfully applied to increase DNA release to the fixative. The protocols resulted in similar success in taxa detection (6.8-7 taxa) but differences in read numbers assigned to taxa of interest (33.8%-93.7%). In comparison to conventional bulk sample metabarcoding of environmental samples, taxa with pronounced exoskeleton and small-bodied taxa were especially underrepresented in ethanol samples. For EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa, which are important for determining stream ecological status, the methods detected 46 OTUs in common, with only 4 unique to the ethanol samples and 10 to the bulk samples. These results indicate that fixative-based metabarcoding is a non-destructive, time-saving alternative for biodiversity assessments focussing on taxa used for ecological status determination. However, for a comprehensive assessment on total invertebrate biodiversity, the method may not be sufficient, and conventional bulk sample metabarcoding should be applied.
A fundamental gap in climate change vulnerability research is an understanding of the relative thermal sensitivity of ectotherms. Aquatic insects are vital to stream ecosystem function and ...biodiversity but insufficiently studied with respect to their thermal physiology. With global temperatures rising at an unprecedented rate, it is imperative that we know how aquatic insects respond to increasing temperature and whether these responses vary among taxa, latitudes, and elevations. We evaluated the thermal sensitivity of standard metabolic rate in stream‐dwelling baetid mayflies and perlid stoneflies across a ~2,000 m elevation gradient in the temperate Rocky Mountains in Colorado, USA, and the tropical Andes in Napo, Ecuador. We used temperature‐controlled water baths and microrespirometry to estimate changes in oxygen consumption. Tropical mayflies generally exhibited greater thermal sensitivity in metabolism compared to temperate mayflies; tropical mayfly metabolic rates increased more rapidly with temperature and the insects more frequently exhibited behavioral signs of thermal stress. By contrast, temperate and tropical stoneflies did not clearly differ. Varied responses to temperature among baetid mayflies and perlid stoneflies may reflect differences in evolutionary history or ecological roles as herbivores and predators, respectively. Our results show that there is physiological variation across elevations and species and that low‐elevation tropical mayflies may be especially imperiled by climate warming. Given such variation among species, broad generalizations about the vulnerability of tropical ectotherms should be made more cautiously.
Schematic of expectations for change in standard metabolic rate (SMR; O2 consumption) and performance in response to temperature in an aquatic ectotherm. The thermal performance curve (TPC; green line) is a functional performance trait where higher performance is better. TOPT, where performance is highest, reflects the animal's preferred temperature. The oxygen consumption curve (dashed line) is a special case of TPC. T‐MRPEAK represents the temperature at which SMR is so high that it equals maximum metabolic rate. Predictions for variation in metabolic rate, based on the Climate Variability Hypothesis, are shown on the right. Our predictions were met in mayflies, but not stoneflies.
We present a genome assembly from an individual male
Nemurella pictetii
(Arthropoda; Insecta; Plecoptera; Nemouridae). The genome sequence is 257 megabases in span. The majority of the assembly ...(99.79%) is scaffolded into 12 chromosomal pseudomolecules, with the X sex chromosome assembled. The X chromosome was found at half coverage, but no Y chromosome was found. The mitochondrial genome was assembled, and is 16.0 kb in length.
Klapálek, 1912 is a small stonefly genus in the Palearctic areas of China and its biodiversity is underestimated.
This paper reports a new species of
,
sp. nov. in the Dajiuhu National Wetland Park ...of Shennongjia Forestry District, Hubei Province, central China. The description and illustrations of the new species are provided, based on male adults, female adults and eggs. The new species can be distinguished from its congeners by the characters of male and female genitalia and the egg structure.
Aim: Dispersal ability has traditionally been seen as a key influence on species distributions, but recent biogeographical analyses have cast doubt on the strength of this association. Here we ...present biogeographical evidence from New Zealand's entire plecopteran fauna (100 species) to test for associations between flight ability and species range, and to determine the extent of wing reduction that is required to influence biogeographical patterns. Location: The main islands of New Zealand, representing a land area of 270,000 km². These islands host a diverse assemblage of endemic stoneflies, including a substantial number of wing-reduced taxa. Methods: We analyse biogeographical data, encompassing over 7000 species/locality records, across all 100 stonefly taxa recorded from New Zealand's mainland. Distributional data are analysed together with morphological data, in a phylogenetic framework, to test the hypothesis that wing length (dispersal ability) has a significant association with range size. Results: Our analyses indicate a strong relationship between species wing length and area of occupancy, unconfounded by phylogenetic relationships. A significant positive correlation was also observed between geographical range and relative wing length in both sexes, with consistent patterns observed in distinct families. When the analysis was confined only to macropterous species the relationship between wing length and area of occupancy remained significant. Main conclusions: This study shows that rapid switches in dispersal ability are linked to dramatic biogeographical contrasts. While complete wing loss is associated with major range reduction, it is also clear that even small reductions in wing size can significantly influence biogeographical patterns. Broadly, the analysis demonstrates that by focusing on a major regional assemblage of ecologically, and phylogenetically, similar taxa, it is possible to show that even subtle morphological shifts can be correlated with substantial biogeographical change.
This article presents data on the study of the fauna of
Plecoptera
watercourses in Uzbekistan. On the basis of original collections of larvae/nymphs and adults of stoneflies and data from literary ...sources, a revision of the fauna of stoneflies of Uzbekistan was carried out, which currently numbers 48 species belonging to 19 genera and 7 families. Among them, endemic species were identified, first identified for Central Asia and for Uzbekistan.
The male drumming signal of the stonefly Taeniopteryx nebulosa from Great Britain is described for the first time. It differs significantly from calls of European males in terms of number of beats ...and total call duration. As such, it justifies continued consideration of British
specimens as a subspecies. Despite there being only one specimen examined we thought it was important to note the differences observed and to consider the significance for the status of the British subspecies.
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