The contribution of insects to global forest deadwood decomposition.

The amount of carbon stored in deadwood is equivalent to about 8 per cent of the global forest carbon stocks1. The decomposition of deadwood is largely governed by climate2-5 with decomposer groups-such as microorganisms and insects-contributing to variations in the decomposition rates2,6,7. At the global scale, the contribution of insects to the decomposition of deadwood and carbon release remains poorly understood7. Here we present a field experiment of wood decomposition across 55 forest sites and 6 continents. We find that the deadwood decomposition rates increase with temperature, and the strongest temperature effect is found at high precipitation levels. Precipitation affects the decomposition rates negatively at low temperatures and positively at high temperatures. As a net effect-including the direct consumption by insects and indirect effects through interactions with microorganisms-insects accelerate the decomposition in tropical forests (3.9% median mass loss per year). In temperate and boreal forests, we find weak positive and negative effects with a median mass loss of 0.9 per cent and -0.1 per cent per year, respectively. Furthermore, we apply the experimentally derived decomposition function to a global map of deadwood carbon synthesized from empirical and remote-sensing data, obtaining an estimate of 10.9 ± 3.2 petagram of carbon per year released from deadwood globally, with 93 per cent originating from tropical forests. Globally, the net effect of insects may account for 29 per cent of the carbon flux from deadwood, which suggests a functional importance of insects in the decomposition of deadwood and the carbon cycle.

Climate-land-use interactions shape tropical mountain biodiversity and ecosystem functions.

Agriculture and the exploitation of natural resources have transformed tropical mountain ecosystems across the world, and the consequences of these transformations for biodiversity and ecosystem functioning are largely unknown1-3. Conclusions that are derived from studies in non-mountainous areas are not suitable for predicting the effects of land-use changes on tropical mountains because the climatic environment rapidly changes with elevation, which may mitigate or amplify the effects of land use4,5. It is of key importance to understand how the interplay of climate and land use constrains biodiversity and ecosystem functions to determine the consequences of global change for mountain ecosystems. Here we show that the interacting effects of climate and land use reshape elevational trends in biodiversity and ecosystem functions on Africa's largest mountain, Mount Kilimanjaro (Tanzania). We find that increasing land-use intensity causes larger losses of plant and animal species richness in the arid lowlands than in humid submontane and montane zones. Increases in land-use intensity are associated with significant changes in the composition of plant, animal and microorganism communities; stronger modifications of plant and animal communities occur in arid and humid ecosystems, respectively. Temperature, precipitation and land use jointly modulate soil properties, nutrient turnover, greenhouse gas emissions, plant biomass and productivity, as well as animal interactions. Our data suggest that the response of ecosystem functions to land-use intensity depends strongly on climate; more-severe changes in ecosystem functioning occur in the arid lowlands and the cold montane zone. Interactions between climate and land use explained-on average-54% of the variation in species richness, species composition and ecosystem functions, whereas only 30% of variation was related to single drivers. Our study reveals that climate can modulate the effects of land use on biodiversity and ecosystem functioning, and points to a lowered resistance of ecosystems in climatically challenging environments to ongoing land-use changes in tropical mountainous regions.

Beyond body size: consistent decrease of traits within orthopteran assemblages with elevation.

Morphological traits provide the interface between species and their environment. For example, body size affects the fitness of individuals in various ways. Yet especially for ectotherms, the applicability of general rules of interspecific clines of body size and even more so of other morphological traits is still under debate. Here we tested relationships between elevation (as a proxy for temperature) and productivity with four ecologically relevant morphological traits of orthopteran assemblages that are related to fecundity (body size), dispersal (wing length), jumping ability (hind femur length), and predator detection (eye size). We measured traits of 160 orthopteran species that were sampled along an extensive environmental gradient at Mt. Kilimanjaro (Tanzania), spanning elevations from 790 to 4,410 m above sea level (a.s.l.) with different levels of plant productivity. For traits other than body size, we calculated the residuals from a regression on body length to estimate the variation of traits irrespective of body size. Bayesian analyses revealed that mean body size of assemblages, as well as the means of relative wing length, hind femur length, and eye size, decreased with increasing elevation. Body size and relative eye size also decreased with increasing productivity. Both phylogenetic relationships, as well as species-specific adaptations, contributed to these patterns. Our results suggest that orthopteran assemblages had higher fecundity and better dispersal and escape abilities, as well as better predator detection at higher temperatures (low elevations) than at low temperatures (high elevations). Large body sizes might be advantageous in habitats with low productivity because of a reduced risk of starvation. Likewise, large eye size might be advantageous because of the ability to detect predators in habitats with low vegetation cover, where hiding possibilities are scarce. Our study highlights that changes in temperature and productivity not only lead to interspecific changes in body size but are also related to independent changes of other morphological traits that influence the ecological fit of organisms in their environment.

Broken bridges: The isolation of Kilimanjaro's ecosystem.

Biodiversity studies of global change mainly focus on direct impacts such as losses in species numbers or ecosystem functions. In this study, we focus on the long-term effects of recent land-cover conversion and subsequent ecological isolation of Kilimanjaro on biodiversity in a paleobiogeographical context, linking our findings with the long-standing question whether colonization of African mountains mainly depended on long-distance dispersal, or whether gradual migration has been possible through habitat bridges under colder climates. For this, we used Orthoptera as bioindicators, whose patterns of endemism and habitat demands we studied on about 500 vegetation plots on Kilimanjaro and Mt. Meru (Tanzania) since 1996. Land-cover changes in the same area were revealed using a supervised classification of Landsat images from 1976 to 2000. In 1976, there was a corridor of submontane forest vegetation linking Kilimanjaro with Mt. Meru, replaced by human settlements and agriculture after 2000. Until recently, this submontane forest bridge facilitated the dispersal of forest animals, illustrated by the large number of endemic submontane forest Orthoptera shared by both mountains. Furthermore, the occurrence of common montane endemics suggests the existence of a former forest corridor with montane vegetation during much earlier times under climatic conditions 2-7°C cooler and 400-1,700 mm wetter than today. Based on the endemicity patterns of forest Orthoptera, negative consequences are predicted due to the effects of isolation, in particular for larger forest animals. Kilimanjaro is becoming an increasingly isolated ecosystem with far reaching consequences for diversity and endemism. Forest bridges between East African mountains acted as important migratory corridors and are not only a prehistoric phenomenon during periods with other climatic conditions but also disappeared in some places recently due to increasing and direct anthropogenic impact.

Taxonomic, bioacoustic and faunistic data on a collection of Tettigonioidea from Eastern Congo (Insecta: Orthoptera).

During a 14-day excursion in March 1990, 28 species of tettigonioids were found at Irangi (1º54'S, 28º27'E), ca.100 km north west of Bukavu at Lake Kivu (Democratic Republic of the Congo, formerly Zaire), and at other localities near Bukavu. One species -Arantia (Arantia) gracilicercata Heller sp. n. - is new to science, another one-Pantecphyllus helleri Schmidt et al. 2004-was already described as new in a generic revision. All our specimens of the morphologically quite diverse and sexually dimorphic phaneropterine genus Arantia were studied using molecular methods. We propose a new subgenus Arantia (Euarantia) Heller subgen. n. based on relative tegmen width. Songs and stridulatory organs were studied in 9 species. Two phaneropterines, Horatosphaga leggei and Pardalota asymmetrica, showed remarkable calling songs lasting more than 10 s and produced by quite complicated stridulatory movements. The song of the large phaneropterine Zeuneria biramosa is noteworthy because of its unusually low carrier frequency of 3.7 kHz. Based on the examination of other specimens and species, some taxonomic changes are proposed (Phaneropteridae Burmeister, 1838 stat. rev.; Afromecopoda monroviana (Karsch, 1886) stat. rev.; Leproscirtus ebneri Karny, 1919, syn. n., Leproscirtus karschi Karny, 1919, syn. n., Leproscirtus granulosus aptera Karny, 1919, syn. n., all synonyms of Leproscirtus granulosus (Karsch, 1886); Lanistoides Sjöstedt, 1913 stat. rev.; Plastocorypha cabrai Griffini, 1909 stat. n.).

The impact of insect herbivory on biogeochemical cycling in broadleaved forests varies with temperature.

Herbivorous insects alter biogeochemical cycling within forests, but the magnitude of these impacts, their global variation, and drivers of this variation remain poorly understood. To address this knowledge gap and help improve biogeochemical models, we established a global network of 74 plots within 40 mature, undisturbed broadleaved forests. We analyzed freshly senesced and green leaves for carbon, nitrogen, phosphorus and silica concentrations, foliar production and herbivory, and stand-level nutrient fluxes. We show more nutrient release by insect herbivores at non-outbreak levels in tropical forests than temperate and boreal forests, that these fluxes increase strongly with mean annual temperature, and that they exceed atmospheric deposition inputs in some localities. Thus, background levels of insect herbivory are sufficiently large to both alter ecosystem element cycling and influence terrestrial carbon cycling. Further, climate can affect interactions between natural populations of plants and herbivores with important consequences for global biogeochemical cycles across broadleaved forests.

Annotated list of Tettigoniidae (Orthoptera) from the East Usambara Mountains, Tanzania and new Tettigoniidae species from East Africa.

A list of the Tettigoniidae (Orthoptera) of the East Usambara Mountains is presented and 16 new species are described from East Africa. A total number of 29 Tettigoniidae species is recorded for the East Usambara Mountains. New species are described from the Shimba Hills in Kenya, coastal Tanzania from the Kazimzumbwi forest reserve, Mt Kilimanjaro, the East and West Usambara and Uluguru Mountains in Tanzania, namely in Conocephalinae Afroagraecia pwania n. sp., Afroagraecia shimbaensis n. sp., Afroanthracites discolor n. sp., Afroanthracites jagoi n. sp. and Afroanthracites viridis n. sp., in Meconematinae Afrophisis flagellata n. sp., Afrophisis kisarawe n. sp., Afrophisis mazumbaiensis n. sp. and Afrophisis pseudoflagellata n. sp., in Hexacentrinae Aerotegmina megaloptera n. sp., in Mecopodinae Apteroscirtus cristatus n. sp., and A. planidorsatus n. sp., in Phaneropterinae Gelotopoia amabilis n. sp., and in Pseudophyllinae Cymatomerella pardopunctata n. sp. and Cymatomera viridimaculata n. sp. Seven species are endemic to the East Usambara Mountains which are 25% of the recorded forest-bound bush crickets. The Tettigoniidae fauna is compared between the East Usambara Mountains and Mt Kilimanjaro and mechanisms of speciation discussed in Orthoptera for the area. New Tettigoniidae records are given for Mt Kilimanjaro (Oxyecous apertus Ragge, Tropidonotacris grandis Ragge and Eurycorypha conclusa Hemp).

A new Lobosceliana Dirsh species (Orthoptera: Pamphagidae: Porthetinae) from coastal Tanzania, East Africa.

A new flightless species of Lobosceliana is described from coastal Tanzania, East Africa. This is the first species within this genus with shortened wings in the male sex. The antennal formula is special in this species as well since it differs from that of other Lobosceliana species, questioning the systematic value of the number of antennal segments in Porthetinae as a useful generic character.

New Phlugidia species (Orthoptera: Tettigoniidae: Meconematinae, Phlugidini) from the Eastern Arc Mountains of Tanzania, Africa.

Two new species of Phlugidia (Orthoptera: Tettigoniidae: Meconematinae) are described from the Eastern Arc Mountains of Tanzania. P. planicercus Hemp n. sp. occurs in lowland forest at the foothills of the Uluguru Mountains, while P. ob- tusicercus Hemp n. sp. was collected in the Nguru Mountains. A key to Phlugidia species is provided.

Annotated list of Ensifera (Orthoptera) and further records on Caelifera (Orthoptera) of Mt Kilimanjaro, Tanzania.

A list of the Tettigoniidae and Gryllacrididae (Orthoptera: Ensifera) of Mt Kilimanjaro is presented. A total number of 63 Ensifera was recorded for this mountain, of which 25 species belonged to Phaneropterinae, 18 to Conocephalinae, 6 to Hetrodinae and three to Pseudophyllinae. The subfamily Meconematinae contributed two species while only one species of the subfamilies Hexacentrinae, Mecopodinae and Saginae was found. Gryllacrididae contributed six species. Three species recorded in literature were not found again during the research period. 15 species are newly recorded for Mt Kilimanjaro in this study and one species of Agraeciini newly described. Two new genera, Afroanthracites Hemp & Ingrisch n. gen. (type species: Anthracites montium Sjöstedt, 1910) and Afroagraecia Ingrisch & Hemp n. gen. (type species: Agraecia sansibara Redtenbacher, 1891), are erected on African Agraeciini (Conocephalinae). Anthracites kilimandjaricus Sjöstedt, 1910 is snonymized with A. montium Sjöstedt, 1910. Agraecia sansibara (Redtenbacher, 1891), Anthracites bloyeti Brongniart, 1897 and Anelytra panteli Karny are transferred to Afroagraecia. Aethiomerus stenorhinus Saussure, 1899 is synonymised with Afroagraecia sansibara (Redtenbacher, 1891). In Caelifera two Catantopinae (Acrididae) species are newly recorded for Mt Kilimanjaro and one pyrgomorphid species, Maura lurida (Fabricius, 1781), recovered again for the area.

Review of song patterns and sound production in armoured ground crickets (Orthoptera: Tettigoniidae: Hetrodini) with karyological data and taxonomic notes.

In the mate finding system of bush-crickets, acoustical signals play a central role. Here we review and describe the bioacoustics of Hetrodini, a morphologically uniform group of Tettigonioidea with a distribution centered in Africa. The male calling songs are produced by tegmino-tegminal stridulation. In all species, these fore wings are completely covered by the pronotum (invisible in intact specimens) and lack the glossy mirror cells which are well-known from many other singing Ensifera. Concerning spectral composition, the broad frequency peak and the parts with the most energy lie in the high audio or low ultrasonic range. In amplitude modulation, the songs are relatively simply structured and contain only one type of syllables each. These syllables consist of heavily dampened impulses (non-resonant song) and are arranged in long series of echemes (chirps) or trills. As far as it is known, syntopic species differ in syllable and/or echeme repetition rates. In contrast to the uniform morphology, the karyotypes are surprisingly diverse with chromosome numbers ranging from 2n = 29 to 17 and one of two sex determination systems: X0 and neo-XY. In our opinion, taxonomically the group is at the moment at best considered as a tribe incertae sedis (without subfamily classification) within Tettigoniidae (not Tettigoniinae sensu OSF).

A new species of Apteroscirtus Karsch, 1891 (Ensifera, Tettigoniidae, Mecopodinae) from Angola.

A new species of Apteroscirtus is described from Angola, enlarging the known area of distribution of this genus to west-southern Africa.

Diversification of the Balloon bushcrickets (Orthoptera, Hexacentrinae, Aerotegmina) in the East African mountains.

East African mountains constitute a network of isolated habitat islands among dry savannah and are thus ideal for studying species diversification processes. This study elucidated the phylogenetic and phylogeographic relationships of all bushcricket species comprising the genus Aerotegmina. Our analysis indicated that large-scale climatic and topographic processes in Africa are likely to have driven speciation in this group, and revealed the cytogenetic traits of the species. Molecular phylogeny supported the monophyly of Aerotegmina and showed that the genus probably originated in the old Eastern Arc Mountains of Tanzania and Kenya. Two lineages were distinguished: small- and large-sized species with geographically distinct habitats. The underlying processes are thought to be eight dispersals, ten vicariance events, and one extinction event linked to repeated fragmentation of the African rainforest. Those processes, in conjunction with habitat change, probably also led to the spatial separation of the species into a northern clade with a diploid number of chromosomes 2n = 32 + X0 or 2n = 30 + neo-XY and a southern clade with a reduced number of chromosomes (2n = 28 + X0 or 24 + neo-X1X2Y). Karyotype analysis suggests that Aerotegmina is currently in the process of speciation.

Highly divergent karyotypes and barcoding of the East African genus Gonatoxia Karsch (Orthoptera: Phaneropterinae).

East Africa is a hotspot of biodiversity of many orthopteran taxa, including bushcrickets. Gonatoxia Karsch, 1889 species are fully alate Phaneropterinae, which are perfectly adapted to the foliage of forests. We examined five species using combined cytogenetic and molecular data to determine the inter- and intraspecific genetic diversity. The variation in the diploid number of chromosomes in males ranged from 2n = 28 + X0 and 26 + X0 to 2n = 6 + X0. Fluorescence in situ hybridization showed from one to many 18S rDNA loci as well as interstitial sequences, especially in G. helleri. 18S rDNA loci coincided with active NOR and C-banding patterns. The isolation of populations of the species explains differences in the number of chromosomes (G. maculata), chromosomal polymorphism and chromosomal heterozygosity (G. helleri). Our molecular phylogeny based on the COI locus supported the monophyly of the genus Gonatoxia and separateness of the five examined species in accordance with their morphological features and chromosome numbers as well as the species' distribution.

Species richness is more important for ecosystem functioning than species turnover along an elevational gradient.

Many experiments have shown that biodiversity enhances ecosystem functioning. However, we have little understanding of how environmental heterogeneity shapes the effect of diversity on ecosystem functioning and to what extent this diversity effect is mediated by variation in species richness or species turnover. This knowledge is crucial to scaling up the results of experiments from local to regional scales. Here we quantify the diversity effect and its components-that is, the contributions of variation in species richness and species turnover-for 22 ecosystem functions of microorganisms, plants and animals across 13 major ecosystem types on Mt Kilimanjaro, Tanzania. Environmental heterogeneity across ecosystem types on average increased the diversity effect from explaining 49% to 72% of the variation in ecosystem functions. In contrast to our expectation, the diversity effect was more strongly mediated by variation in species richness than by species turnover. Our findings reveal that environmental heterogeneity strengthens the relationship between biodiversity and ecosystem functioning and that species richness is a stronger driver of ecosystem functioning than species turnover. Based on a broad range of taxa and ecosystem functions in a non-experimental system, these results are in line with predictions from biodiversity experiments and emphasize that conserving biodiversity is essential for maintaining ecosystem functioning.

New species of Mecopodinae (Orthoptera, Tettigoniidae) from Tanzania.

New species of Mecopodinae are described from Tanzanian mountain ranges. These are Apteroscirtus densissimus n. sp. from the Nguru Mountains, Gymnoscirtus corifterus n. sp. from the Udzungwa Mountains Nationalpark and a new subspecies of Phyloscirtus cordipennis Karsch, P. c. spinosus n. ssp. from the Nguru Mountains. Data on habitat are provided.

A new species of Stenampyx Karsch, 1890 from East Africa (Orthoptera: Tettigoniidae, Pseudophyllinae, Phyllomimini)-evidence of a former connection of West-Central and East African forests.

A new Stenampyx, S. viridiflavum n. sp., is described from Tanzania. Stenampyx was monotypic and known from Central to West African forests. As with the genus Pseudotomias Hemp, the newly described species in Stenampyx shows a close relationship to the Central and East African forest fauna.

Rapid chromosomal evolution in the bush-cricket Gonatoxia helleri Hemp, 2016 (Orthoptera, Phaneropterinae).

Gonatoxia helleri Hemp, 2016 is one of the most widespread bush-crickets of the genus Gonatoxia Karsch, 1889 in East Africa. This species with seven large chromosomes (2n♂ = 7) differs from other representatives of the genus Gonatoxia drastically by its reduced chromosome number, the asymmetrical karyotype including karyomorphs rarely found in tettigoniids, as well as in irregularities in the course of meiosis. To better understand the origin of such an exceptional karyotype, chromosomes of 29 specimens from four populations/localities were studied using classical techniques, such as C-banding, silver impregnation, fluorochrome double staining and fluorescence in situ hybridization (FISH) technique with 18S rDNA and (TTAGG) n telomeric probes. FISH showed many 18S rDNA loci as well as interstitial telomeric sequences, where chromosome morphology varied in these components in terms of quantity and distribution. The 18S rDNA loci coincided with active NORs and C-banding patterns. We suggest that a combination of Robertsonian rearrangements and/or multiple common tandem fusions involving the same chromosomes contributed to the formation of this karyotype/karyomorphs. The results are the first step towards a better understanding of chromosomal reorganization and evolution within the genus Gonatoxia. Low chromosome number, together with the incidence of chromosomal polymorphism that is higher in G. helleri than previously reported in bush-crickets, implies that this species can be a valuable new model for cytogenetic and speciation studies. Our findings suggest that chromosomal translocations lead to diversification and speciation in this species and could be the driving force of adaptive radiation.

Climatic change as an engine for speciation in flightless Orthoptera species inhabiting African mountains.

Many East African mountains are characterized by an exceptionally high biodiversity. Here we assess the hypothesis that climatic fluctuations during the Plio-Pleistocene led to ecological fragmentation with subsequent genetic isolation and speciation in forest habitats in East Africa. Hypotheses on speciation in savannah lineages are also investigated. To do this, mitochondrial DNA sequences from a group of bush crickets consisting of both forest and savannah inhabiting taxa were analysed in relation to Plio-Pleistocene range fragmentations indicated by palaeoclimatic studies. Coalescent modelling and mismatch distributions were used to distinguish between alternative biogeographical scenarios. The results indicate two radiations: the earliest one overlaps in time with the global spread of C4 grasslands and only grassland inhabiting lineages originated in this radiation. Climatically induced retraction of forest to higher altitudes about 0.8 million years ago, promoting vicariant speciation in species inhabiting the montane zone, can explain the second radiation. Although much of the biodiversity in East Africa is presently threatened by climate change, past climatic fluctuations appear to have contributed to the species richness observed in the East African hot spots. Perceiving forests as centres of speciation reinforces the importance of conserving the remaining forest patches in the region.

Orthoptera (Tettigoniidae and Acridoidea) from Miombo woodlands of Central Tanzania with the description of new taxa.

A list of the Orthoptera of Miombo woodlands of the Manyara, Dodoma and Tabora Regions of Tanzania is presented. 64 Ensifera species were recorded of which two genera (Kefalia n. gen. with three species newly described; Sentia n. gen., 1 species) and Melidia adfinia n. sp. are new to science. Further 4 new species of Acrometopini are described from the area (Horatosphaga laticerca n. sp., Horatosphaga scalata n. sp., Peronura wottae n. sp., and Tenerasphaga mpwapwae n. sp.). 78 Acridoidea species were recorded. Miombo woodlands are vanishing rapidly these days so that faunal information will become an important tool to measure habitat quality of a certain forested area and for restauration measures. The species Peronura wottae n. sp. and Kefalia grafika n. sp. must be considered as Critically Endangered since only known from Wotta Forest Reserve on the Mpwapwa plateau. This forest reserve is heavily degraded by illegal cutting and lifestock grazing and will disappear in the near future if no immediate measures are taken by responsible authorities.