Impacts of detritivore diversity loss on instream decomposition are greatest in the tropics.

The relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore diversity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between diversity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore diversity is already relatively low and some environmental stressors particularly prevalent.

Latitude dictates plant diversity effects on instream decomposition.

Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low and high functional diversity in 40 streams on 6 continents and spanning 113° of latitude. Despite important variability in our dataset, we found latitudinal differences in the effect of litter functional diversity on decomposition, which we explained as evolutionary adaptations of litter-consuming detritivores to resource availability. Specifically, a balanced diet effect appears to operate at lower latitudes versus a resource concentration effect at higher latitudes. The latitudinal pattern indicates that loss of plant functional diversity will have different consequences on carbon fluxes across the globe, with greater repercussions likely at low latitudes.

A new black fly species of Simulium (Nevermannia) (Simuliidae: Diptera) from the Southern Eastern Ghats, India.

A new black fly species, Simulium (Nevermannia) karavalliense sp. nov. is described from Southern Eastern Ghats of South India. This new species is placed in the Simulium ruficorne species-group of the subgenus Nevermannia. S. (N.) karavalliense sp. nov. is characterized by female with a long sensory vesicle, male upper eye with 14 vertical columns and 16 horizontal rows of large facets, pupal gill with 8 filaments and larval hypostoma with 6 hypostomal bristles lying parallel to lateral margin. Taxonomic keys are provided to distinguish this new species from related species in India.

Two new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from South India.

Two new black fly species, Simulium (Gomphostilbia) dinakarani sp. nov. and Simulium (Gomphostilbia) krishnani sp. nov. are described based on reared adult, pupal and larval specimens collected from the Western Ghats of India. These two new species are placed in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein. The morphological characters of two new species are compared with other related species of batoense species-group in India. The COI gene has successfully differentiated these two new species from its allies, S. (G.) panagudiense and S. (G.) takaokai of the batoense species group and the phylogenetic analysis by using COI gene sequences supporting its morphological classification.

A new mayfly species of Choroterpes (Euthraulus) (Ephemeroptera: Leptophlebiidae) from South India.

A new mayfly species, Choroterpes (Euthraulus) kalladaensis sp. n. is described based on nymphs and subimagoes from South India. The nymph of Choroterpes (Euthraulus) kalladaensis sp. n. is characterized by a labrum with antero-median emargination well broad and 'V' shaped, femora with two black spots on median and basal region, claw with 2 sections of 13 denticles with 3 smaller serrations, posteriolateral spines present on segment 2-9, paraprocts smooth with pores and their inner margin with small triangular spines and outer margin with long setae and in the subimago the fore wing has four intercalary veins between costa and subcosta, penis lobes are short, membranous, separated apically and covered with minute setae. Taxonomic notes are given to distinguish this new species from closely related species.

A new mayfly species of Rhoenanthus (Ephemeroptera: Potamanthidae) from Peninsular India.

A new mayfly species, Rhoenanthus (Rhoenanthus) tungaiensis sp. nov. is described and characterized at the larval stage by fore tibiae relatively long with dense hair like setae on dorsal and lateral surface, male compound eyes large, mandibular tusks 0.8 times longer than head length, segment I of maxillary palpi 1.7 times longer than segment II, fore femur 2.9 times longer than its greatest width, gill III with 46-48 marginal fibrillae on lateral margin of dorsal lamellae and 35-37 on ventral lamellae. At the imaginal stage, the new species can be separated by inverted bell shaped markings on terga, purplish brown intercalaries in forewings, costal cross veins reddish brown and infuscated, MP2 connected to CuA basally.

A new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from South India.

Simulium (Gomphostilbia) kumbakkaraiense sp. n. is described based on adults, pupae and mature larvae from Kumbakkarai stream, in the Palani Hills of Western Ghats, South India. This new species is placed in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein. This new species is characterized by a scutum with three brownish-black longitudinal vittae and hind basitarsus in the female 5.3 times as long as wide, and in male the large facets of the upper eye in 13 vertical columns and 14 horizontal rows, the respiratory gill with short common basal in the pupa and postgenal cleft arrow-head-shaped in the larva. Taxonomic notes are provided to distinguish this new species from related species. [Zoobank register: http://zoobank.org/urn:lsid:zoobank.org:act:C575FB25-B6B2-414B-AE11-0468A1871DFA].

Periphytic diatom colonization and litter decomposition in an intermittent stream of South India.

We examined the dynamic of periphytic diatom colonization and litter decompositional pattern in an intermittent stream of South India. Litter bags containing 5 g of fresh fallen leaves (belongs to five different species of angiosperms) were fixed in the five stream pools and they were collected after 7, 14, 21, and 28 days of incubation. This experiment showed the diversity, richness, and abundance of diatoms developed on leaf litter. In total, 131 µl-1 cells of diatoms under four species in three families were collected from decomposing leaves in benthic area of stream pools. During experiment, 142 µl-1 cells representing 11 taxa in 10 families were observed in litter bags. The colonization of epiphytic diatom was rapid in early stage of litter decomposition. The higher number of colonization made by Asterionella and Stenopterobia found in litter bags of all experimental weeks. These findings suggest that the rapid microbial colonization (ephiphytic algae) was occurred in the early stage of litter decomposition in an intermittent tropical stream and a comprehensive ecological investigation in perennial natural streams in India is needed.

Species diversity of black flies (Diptera: Simuliidae) in Oriental region and molecular phylogeny of the subgenus Gomphostilbia members.

BACKGROUND & OBJECTIVES: Black flies (Diptera: Simuliidae) are ecologically and medically important insects. Female adults of black flies are the solitary vectors of river blindness (onchocerciasis) and their larvae play a vital role in stream ecosystem. This study examined the distribution of black flies in the Oriental region and analyzed the phylogenetic relationship of the subgenus Gomphostilbia members based on two molecular loci. METHODS: The distribution data of black fly species in different countries of Oriental region were obtained from world black flies geographic inventory. The two gene sequences, COI and ITS1 were used to study the phylogenetic relationships of the members of subgenus Gomphostilbia members. RESULTS: The distribution analysis revealed that out of the 16 subgenera in the genus Simulium Latreille s., the species-level diversity of three subgenera (Gomphostilbia, Nevermannia and Simulium) contributes about thrice of total black fly species diversity. The highest diversity of species was found in the subgenus Simulium. The strict consensus of Tree analysis using New Technology (TNT) and Maximum Likelihood (ML) recovered similar topolo- gies for Gomphostilbia members and they formed as monophyly. The overall sequence identities of the 19 species of subgenus Gomphostilbia were high and shared 55-60% similarity. INTERPRETATION & CONCLUSION: Results of this study highlighted that eight subgenera of Simulium Latreille s. str are commonly distributed in different parts of Oriental region. Among these the subgenera of Simulium, Gomphostilbia and Nevermannia are most common with high diversity in China, Pakistan, Thailand and Vietnam. The phylogenetic analysis of Gomphostilbia members demonstrates the inter-specific divergence, indicating the centre of origin (India) or the recipient of ancestral migrant lineages in Oriental region.

A new species of Prosopistoma Latreille, 1833 (Ephemeroptera: Prosopistomatidae) from South India.

A new species of Prosopistoma (Ephemeroptera: Prosopistomatidae) is described on the basis of mature nymphs from Coorg, Karnataka, South India. Prosopistoma coorgum, new species can be readily distinguished from the other members of Prosopistoma by the following combination of characters: inner margin of outer canine near apex with 2-3 short spines, the length ratio of maxillary palp segments (3.3:4.8:1), ventral margin of fore tibia with 6-8 pectinate setae, and gill II leaf-like and cleft.

A new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from South India, with keys to Indian members of the subgenus Gomphostilbia.

A new black fly species, Simulium (Gomphostilbia) cauveryense sp. n., is described based on adult female, adult male, pupal and larval specimens collected from Kushalanagar, Karnataka, South India. This new species is placed in the decuplum subgroup of the batoense species-group within the subgenus Gomphostilbia. Keys to the species of the subgenus Gomphostilbia reported from India are provided for females, males, pupae and mature larvae.

Two new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from Peninsular India with keys to Peninsular Indian members of the genus Simulium.

Two new species of black flies, Simulium (Gomphostilbia) peteri sp. nov. and S. (G.) takaokai sp. nov., are described on the basis of reared adult, pupal and larval specimens collected from Peninsular India. These two new species are placed in the batoense species group within the subgenus Gomphostilbia. S. (G.) peteri sp. nov. is distinguished in the female by having a medium-sized round opening of the sensory vesicle and a large basal tooth on the claw, in the male by 12 vertical columns in the upper eye large facets, in the pupa by a ventral pair of 2 gill filaments somewhat thicker than the other filaments and in the larva by 5 hypostomal bristles per side lying parallel to the lateral margin. S. (G.) takaokai sp. nov. is characterized in the pupa by having the eight gill filaments with a medium-long common basal stalk and in the larva by the labral fan with 38 main rays and 4 hypostomal bristles on each side. Keys to 13 black fly species reported from Peninsular India are provided for females, males and pupae.