Claudia Hemp

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.

Acoustic Communication in Phaneropterinae (Tettigonioidea) - A Global Review with Some New Data

Abstract Phaneropterinae is the largest subfamily within the bush-crickets/ katydids (Tettigonioidea), with about 2451 species, and with a world-wide distribution. Its acoustic communication differs from all other tettigonioid groups in that females primarily and typically respond to the male calling song with their own acoustic reply, a behaviour referred to as duetting. This type of response seems to have been lost only in a few species with wingless females. According to our literature review, information about the song patterns of about 330 species of Phaneropterinae have been published world-wide. Included in this number are ca 170 species of Barbitistini, a flightless West Palearctic tribe, which are treated separately. In the present study we summarize information from the above 330 species. We examine the morphology of stridulatory and hearing organs, and analyze the acoustic signals for frequency, number of syllables and number of interval types. We also have examined if and how responding by sound may have influenced other aspects of the acoustic communication system, especially the structure of the male calling song. Overall, the songs of male Phaneropterinae are similar to those of other tettigonioids. However, some Phaneropterinae species with very long and complex songs are found on all continents, exceeding in these characters nearly all other Ensifera species. These songs contain several different types of syllables and intervals of various duration. Because of this high interspecific variability (reaching from very simple to extremely complex), male phaneropterine songs are by far more variable than those of other tettigonioid families. However, since there are so few data on the behaviour of most Phaneropterinae species, and especially for females, we still are limited in our understanding of the reasons behind the song variability. Sexual selection by females choosing to respond preferentially to certain song types could be an important evolutionary force, but probably only in combination with some unknown ecological and behavioural factors.

Predictors of elevational biodiversity gradients change from single taxa to the multi-taxa community level.

The factors determining gradients of biodiversity are a fundamental yet unresolved topic in ecology. While diversity gradients have been analysed for numerous single taxa, progress towards general explanatory models has been hampered by limitations in the phylogenetic coverage of past studies. By parallel sampling of 25 major plant and animal taxa along a 3.7 km elevational gradient on Mt. Kilimanjaro, we quantify cross-taxon consensus in diversity gradients and evaluate predictors of diversity from single taxa to a multi-taxa community level. While single taxa show complex distribution patterns and respond to different environmental factors, scaling up diversity to the community level leads to an unambiguous support for temperature as the main predictor of species richness in both plants and animals. Our findings illuminate the influence of taxonomic coverage for models of diversity gradients and point to the importance of temperature for diversification and species coexistence in plant and animal communities.

The Phlesirtes complex (Orthoptera, Tettigoniidae, Conocephalinae, Conocephalini) reviewed: integrating morphological, molecular, chromosomal and bioacoustic data.

The tettigoniid genus Phlesirtes Bolivar and its allies are reviewed. Morphological, ecological and molecular data prompt the erection of the new genus Chortoscirtesgen.n. with type species Xiphidion meruense Sjöstedt. The genera Phlesirtes, Chortoscirtes, Karniella and Naskreckiella are characterized by morphological characters supported by molecular, acoustic, ecological and chromosomal data. Four species, Chortoscirtes pseudomeruensissp.n., C. masaicussp.n., C. puguensissp.n. and C. serengetisp.n., are described from localities in northern and coastal Tanzania and one Karniella, K. crassicercasp.n., is described from Uganda. The following comb n. are proposed: Phlesirtes kibonotensis (Sjöstedt) and Phlesirtes kilimandjaricus (Sjöstedt). Subtribal status is proposed for the four investigated African genera. A key to the Chortoscirtes species is provided.

Annotated List of Caelifera (Orthoptera) of Mt. Kilimanjaro, Tanzania

Abstract A list of the Caelifera (Tetrigoidea, Eumastacoidea, and Acridoidea) of Mt Kilimanjaro is presented. A total number of 139 Caelifera was recorded for this mountain, of which 8 species belonged to Tetrigidae, 5 to Eumastacoidea and 126 to Acridoidea. Of the 126 Acridoidea, 2 species belonged to the family Pamphagidae, 14 to the family Pyrgomorphidae, and 3 to the family Lentulidae. The family Acrididae is comprised of 107 species; only one species was recorded for the subfamilies Spathosterninae, Oxyinae, and Euryphyminae, two species within Tropidopolinae, 4 species within Coptacridinae, 5 species each within Hemiacridinae and Calliptaminae, and 7 species each in Eyprepocnemidinae and Cyrtacanthacridinae. The majority of species were found within the four subfamilies Gomphocerinae and Catantopinae (each 14 species), Acridinae (21 species), and Oedipodinae (25 species). Mt Kilimanjaro harbors about 25% of the Acridomorpha species recorded for Tanzania. Together with Mt Meru, with which Kilimanjaro is connected by a ridge at submontane level, 9.4% of the Caelifera are endemics.

Molecular phylogeny of the endemic East African flightless grasshoppers Altiusambilla Jago, Usambilla (Sjöstedt) and Rhainopomma Jago (Orthoptera: Acridoidea: Lentulidae)

Abstract A molecular phylogeny of endemic flightless grasshoppers is presented for the three Lentulidae genera Altiusambilla Jago, 1981 , Usambilla Sjöstedt, 1909 and Rhainopomma Jago, 1981 based on DNA sequences (16S rRNA locus). Parsimony, distance and likelihood reconstructions were performed using different assumptions on sequence evolution. The generated phylogenies agree in almost all parts of the calculated trees and support the monophyly of the observed genera. It was shown that Usambilla and Rhainopomma are more closely related to each other, Altiusambilla being a separate clade. However, the investigated East African lentulid genera are clearly separated from South African taxa, underlining the monophyly of East African genera. Usambilla olivacea is re‐established. Populations of Rhainopomma montanum from the Taita Hills of Kenya and from the West Usambara mountains of Tanzania are two separate species not closely related to each other. Rhainopomma samples from the North Pare mountains of Tanzania belong to a hitherto undescribed species.

Aerotegmina, a new genus of African Listroscelidinae (Orthoptera: Tettigoniidae, Listroscelidinae, Hexacentrini)

Abstract A new genus, Aerotegmina is proposed for an East African Listroscelidinae species occurring in the montane forests of Mt. Kilimanjaro, Tanzania. Notes on distribution and habitat are given.

New Lentulidae species from East Africa (Orthoptera: Saltatoria)

Abstract New species of Rhainopomma and of Altiusambilla from the northern part of the Eastern Arc mountains of Tanzania are described, based on morphological, molecular and geographical data. Ancestors of the genera Usambilla, Rhainopomma and Altiusambilla probably spread when a different climatic regime favored forest cover connecting presently isolated high mountains of East Africa. After forests retreated, allopatric speciation was the driving force resulting in the biographical pattern of closely related lentulid species we see today in the Eastern Arc mountains and inland volcanoes of Tanzania and Kenya.

A new genus of African Karniellina (Orthoptera, Tettigoniidae, Conocephalinae, Conocephalini): integrating morphological, molecular and bioacoustical data

Melanoscirtes gen.n. is established within Karniellina. The members of this subtribe are small conocephaline bush crickets, confined to Africa. Melanoscirtes is erected on Phlesirtes kibonotensis, a species restricted to forest clearings and forest edge in the submontane and montane zones of Mt. Kilimanjaro. A subspecies, M. kibonotensis uguenoensis, is described from the North Pare mountains, a mountain range of the Eastern Arc adjacent to Mt. Kilimanjaro. Further species of Melanoscirtes occur on other mountain ranges of the northern branch of the Eastern Arc mountains of northern Tanzania and southern Kenya. The South Pare mountains harbour M. shengenae; the West Usambaras, M. usambarensis, and the Taita Hills, M. taitensis. All species and subspecies of Melanoscirtes exhibit a similar morphology and occupy analogous habitats on the respective mountains. The song patterns for all species found within this genus are very similar, and this, together with evidence from molecular data, suggests that allopatric speciation is the reason for the biogeographic pattern found in this genus. A key for the subspecies and species of Melanoscirtes is provided.

New Acrometopae from East Africa (Tettigoniidae: Phaneropterinae)

Abstract Two new species of Acrometopae and the female of Lamecosoma inermis Ragge are described from Tanzania, East Africa. Horatosphaga parensis n. sp. occurs in montane forest clearings of the South and North Pare Mountains. Peronura uguenoensis n. sp. inhabits herbaceous vegetation in the North Pare Mts. Notes on altitudinal distribution and habitat requirements are given for both species. L. inermis is an inhabitant of the savannah grasslands in the colline and submontane zone of southeast and eastern Kilimanjaro.