Comparative Analyses of Phenotypic Sequences Using Phylogenetic Trees.

Phenotypic sequences are a type of multivariate trait organized structurally, such as teeth distributed along the dental arch, or temporally, such as the stages of an ontogenetic series. Unlike other multivariate traits, the elements of a phenotypic sequence are distributed along an ordered set, which allows for distinct evolutionary patterns between neighboring and distant positions. In fact, sequence traits share many characteristics with molecular sequences, although important distinctions pose challenges to current comparative methods. We implement an approach to estimate rates of trait evolution that explicitly incorporates the sequence organization of traits. We apply models to study the temporal pattern evolution of cricket calling songs. We test whether neighboring positions along a phenotypic sequence have correlated rates of evolution or whether rate variation is independent of sequence position. Our results show that cricket song evolution is strongly autocorrelated and that models perform well when used with sequence phenotypes even under small sample sizes. Our approach is flexible and can be applied to any multivariate trait with discrete units organized in a sequence-like structure.

Novel system of communication in crickets originated at the same time as bat echolocation and includes male-male multimodal communication.

Understanding the evolutionary origins of communication signals requires careful study of multiple species within a known phylogenetic framework. Most cricket species produce low-frequency calls for mate attraction, whereas they startle to high-frequency sounds similar to bat echolocation. Male crickets in the tribe Lebinthini produce high-frequency calls, to which females reply with vibrational signals. This novel communication system likely evolved by male sensory exploitation of acoustic startle to high-frequency sounds in females. This behavior was previously described for the Lebinthini from Asia. Here we demonstrate that this novel communication system is found in a Neotropical species, Ponca hebardi, and is therefore likely shared by the whole tribe Lebinthini, dating the origin of this behavior to coincide with the origin of echolocation in bats. Furthermore, we document male duets involving both acoustic and vibratory signals not previously described in crickets, and we tentatively interpret it as competitive masking between males.

Phylo-comparative analyses reveal the dual role of drift and selection in reproductive character displacement.

When incipient species meet in secondary contact, natural selection can rapidly reduce costly reproductive interactions by directly targeting reproductive traits. This process, called reproductive character displacement (RCD), leaves a characteristic pattern of geographic variation where divergence of traits between species is greater in sympatry than allopatry. However, because other forces can also cause similar patterns, care must be given in separating pattern from process. Here we show how the phylo-comparative method together with genomic data can be used to evaluate evolutionary processes at the population level in closely related species. Using this framework, we test the role of RCD in speciation of two cricket species endemic to Anatolian mountains by quantifying patterns of character displacement, rates of evolution and adaptive divergence. Our results show differing patterns of character displacement between species for reproductive vs. non-reproductive characters and strong patterns of asymmetric divergence. We demonstrate diversification results from rapid divergence of reproductive traits towards multiple optima under the dual influence of strong drift and selection. These results present the first solid evidence for RCD in Anatolian mountains, quantify the amount of drift and selection necessary for RCD to lead to speciation, and demonstrate the utility of phylo-comparative methods for quantifying evolutionary parameters at the population level.

Identification of two species of Binema Travassos 1925 (Oxyurida: Travassosinematidae) and Cameronia arecoensis Marchissio and Miralles 1987 (Oxyurida: Thelastomatidae) based on morphological and 18S rRNA partial sequence.

Oxyurid nematodes parasitizing the mole cricket Neoscapteriscus vicinus were isolated in the framework of sampling fields of mole-crickets from the pampean region, in Argentina. In this work, molecular characterization of the 18S rRNA partial sequence of nematodes belonging to the families Thelastomatidae (Cameronia arecoensis Marchissio and Miralles 1987) and Travassosinematidae (Binema korsakowi Sergiev 1923 and Binema klossae, Marchissio and Miralles 1993) were carried out. This is the first world report of sequences belonging to B. klossae and C. arecoensis and first Argentinian report of B. korsakowi sequence. Also, morphological and morphometric features of B. klossae, B. korsakowi and C. arecoensis from Argentinian populations are reported.

Biogeographic patterns and diversification dynamics of the genus Cardiodactylus Saussure (Orthoptera, Grylloidea, Eneopterinae) in Southeast Asia.

Southeast Asia harbors an extraordinary species richness and endemism. While only covering 4% of the Earth's landmass, this region includes four of the planet's 34 biodiversity hotspots. Its complex geological history generated a megadiverse and highly endemic biota, attracting a lot of attention, especially in the field of island biogeography. Here we used the cricket genus Cardiodactylus as a model system to study biogeographic patterns in Southeast Asia. We carried out molecular analyses to: (1) infer phylogenetic relationships based on five mitochondrial and four nuclear markers, (2) estimate divergence times and infer biogeographical ancestral areas, (3) depict colonization routes, and summarize emigration and immigration events, as well as in situ diversification, and (4) determine whether shifts in species diversification occurred during the course of Cardiodactylus evolution. Our results support the monophyly of the genus and of one of its species groups. Dating and biogeographical analyses suggest that Cardiodactylus originated in the Southwest Pacific during the Middle Eocene. Our reconstructions indicate that Southeast Asia was independently colonized twice during the Early Miocene (ca. 19-16 Million years ago), and once during the Middle Miocene (ca. 13 Million years ago), with New Guinea acting as a corridor allowing westward dispersal through four different passageways: Sulawesi, the Philippines, Java and the Lesser Sunda Islands. Sulawesi also served as a diversification hub for Cardiodactylus through a combination of high immigration and in situ diversification events, which can be accounted for by the complex geological history of the Wallacea region.

A revised phylogeny of macropathine cave crickets (Orthoptera: Rhaphidophoridae) uncovers a paraphyletic Australian fauna.

Australian cave crickets are members of the subfamily Macropathinae (Orthoptera: Rhaphidophoridae). The subfamily is thought to have originated prior to the tectonic separation of the supercontinent Gondwana based on distributions of extant lineages and molecular phylogenetic evidence, although the Australian fauna have been underrepresented in previous studies. The current study augments existing multigene data (using 12S, 16S, and 28S rRNA genes) to investigate the placement of the Australian representatives within the Macropathinae and to assess divergence dates of select clades. Results suggest that the endemic Tasmanian genus Parvotettix is the sister lineage to the remaining members of the subfamily, an outcome that presents a paraphyletic Australian fauna in contrast to previous studies. All other Australian taxa represented in this study (Micropathus and Novotettix) emerged as a sister group to the New Zealand and South American macropathine lineages. Estimation of phylogenetic divergence ages among the aforementioned clades were calibrated using two methods, in absence of suitable fossil records: (i) tectonic events depicting the fragmentation of Gondwanan landmasses that invoke vicariant scenarios of present day geographic distributions; and (ii) molecular evolutionary rates. Geological calibrations place the median age of the most recent common ancestor of extant macropathines at ∼125 to ∼165 Ma, whereas analyses derived from molecular substitution rates suggest a considerably younger origin of ∼32 Ma. This phylogenetic study represents the most rigorous taxonomic sampling of the Australian cave cricket fauna to date and stresses the influence of lineage representation on biogeographic inference.

Evolutionarily conserved coding properties favour the neuronal representation of heterospecific signals of a sympatric katydid species.

To function as a mechanism in premating isolation, the divergent and species-specific calling songs of acoustic insects must be reliably processed by the afferent auditory pathway of receivers. Here, we analysed the responses of interneurons in a katydid species that uses long-lasting acoustic trills and compared these with previously reported data for homologous interneurons of a sympatric species that uses short chirps as acoustic signals. Some interneurons of the trilling species respond exclusively to the heterospecific chirp due to selective, low-frequency tuning and "novelty detection". These properties have been considered as evolutionary adaptations in the sensory system of the chirper, which allow it to detect signals effectively during the simultaneous calling of the sympatric sibling species. We propose that these two mechanisms, shared by the interneurons of both species, did not evolve in the chirper to guarantee its ability to detect the chirp under masking conditions. Instead we suggest that chirpers evolved an additional, 2-kHz component in their song and exploited pre-existing neuronal properties for detecting their song under masking noise. The failure of some interneurons to respond to the conspecific song in trillers does not prevent intraspecific communication, as other interneurons respond to the trill.

First Occurrence and Paleo-Ecological Implications of Insects (Orthoptera: Ensifera Gryllidae) in the Romualdo Member of the Santana Formation, Eo-Cretaceous of the Araripe Basin.

The Romualdo Member of the Santana Formation, a lithostatigraphic unit attributed to a marine intrusion, is famous for its preserved fossils in calcareous concretions, which stand out for their diversity and excellent preservation levels. This paper aims to record the first occurrence of the Class Insecta in the Romualdo Member of the Santana Formation of the Araripe Basin, as well as to describe and discuss the paleo-ecological implications of such finding. The first occurrence of the order Orthoptera (family Gryllidae) is presented for this unit. This new species is attributed to the genus Araripegryllus, that lasted throughout the deposition of the Crato Member, which is under the Romualdo Member. In reference to its statigraphic origin, the specimens was named Araripegryllus romualdoi sp. nov.

Modelling competition and dispersal in a statistical phylogeographic framework.

Competition between organisms influences the processes governing the colonization of new habitats. As a consequence, species or populations arriving first at a suitable location may prevent secondary colonization. Although adaptation to environmental variables (e.g., temperature, altitude, etc.) is essential, the presence or absence of certain species at a particular location often depends on whether or not competing species co-occur. For example, competition is thought to play an important role in structuring mammalian communities assembly. It can also explain spatial patterns of low genetic diversity following rapid colonization events or the "progression rule" displayed by phylogenies of species found on archipelagos. Despite the potential of competition to maintain populations in isolation, past quantitative analyses have largely ignored it because of the difficulty in designing adequate methods for assessing its impact. We present here a new model that integrates competition and dispersal into a Bayesian phylogeographic framework. Extensive simulations and analysis of real data show that our approach clearly outperforms the traditional Mantel test for detecting correlation between genetic and geographic distances. But most importantly, we demonstrate that competition can be detected with high sensitivity and specificity from the phylogenetic analysis of genetic variation in space.

Changing resonator geometry to boost sound power decouples size and song frequency in a small insect.

Despite their small size, some insects, such as crickets, can produce high amplitude mating songs by rubbing their wings together. By exploiting structural resonance for sound radiation, crickets broadcast species-specific songs at a sharply tuned frequency. Such songs enhance the range of signal transmission, contain information about the signaler's quality, and allow mate choice. The production of pure tones requires elaborate structural mechanisms that control and sustain resonance at the species-specific frequency. Tree crickets differ sharply from this scheme. Although they use a resonant system to produce sound, tree crickets can produce high amplitude songs at different frequencies, varying by as much as an octave. Based on an investigation of the driving mechanism and the resonant system, using laser Doppler vibrometry and finite element modeling, we show that it is the distinctive geometry of the crickets' forewings (the resonant system) that is responsible for their capacity to vary frequency. The long, enlarged wings enable the production of high amplitude songs; however, as a mechanical consequence of the high aspect ratio, the resonant structures have multiple resonant modes that are similar in frequency. The drive produced by the singing apparatus cannot, therefore, be locked to a single frequency, and different resonant modes can easily be engaged, allowing individual males to vary the carrier frequency of their songs. Such flexibility in sound production, decoupling body size and song frequency, has important implications for conventional views of mate choice, and offers inspiration for the design of miniature, multifrequency, resonant acoustic radiators.

A new species of Velarifictorus (Pseudocoiblemmus) from Thailand (Gryllidae; Gryllinae; Modicogryllini) with key to species.

One new species of Velarifictorus (Pseudocoiblemmus) is described from Thailand: Velarifictorus (Pseudocoiblemmus) bilobus sp. n. A key to all known species of Velarifictorus (Pseudocoiblemmus) is provided.

The phallic structures in Gryllotalpidae (Orthoptera: Gryllotalpoidea), and its generic implications.

A nomenclature for phallic structures of members of the family Gryllotalpidae is proposed. Genital structures of the main genera of mole crickets are described, discussing the relationships among subfamilies and their generic delimitation. A key is provided for separation of genera based on genitalia structure. Finally, parthenogenesis in genus Gryllotalpella is recorded for the first time.

The phylogeny of mole crickets (Orthoptera: Gryllotalpoidea: Gryllotalpidae).

The monophyly and phylogenetic relationships of the family Gryllotalpidae were researched. Twenty-six in-group taxa, representing all known genera of Gryllotalpidae were included in a cladistic analysis, based on 89, morphological characters (including genital characters of the males). The different analyses of the resulting data matrix supported the monophyly of Scapteriscinae and Gryllotalpinae and its internal group. Subfamilies, tribes and genera of Gryllotalpidae are fully diagnosed, illustrated and keys to their identification are provided. Four tribes are established (Indioscaptorini n. trib. (Scapteriscinae), Triamescaptorini n. trib., Gryllotalpellini n. trib. and Neocurtillini n. trib. (Gryllotalpinae)) and two other are fully delimited (Scapteriscini stat. rev. and Gryllotalpini stat. rev.). Two new genera are described (Neoscapteriscus n. gen. and Leptocurtilla n. gen.) and as well as seven new species: Gryllotalpella rehni n. sp., G. tindalei n. sp., G. lawrencei n. sp., Neocurtilla ingrischi n. sp., N. townsendi n. sp., Leptocurtilla juanmanueli n. sp. and L. chopardi n. sp. The following nomenclatural changes were made: All species previously placed in Scapteriscus s.l. are transferred to the new genus Neoscapteriscus, except Scapteriscus oxydactilus and S. headsi that are still placed in Scapteriscus, Gryllotalpa chilensis reinst. stat. and Leptocurtilla maranona, n. comb. Finally, previous contributions about the phylogenetic relationships of molecrickets are contrasted with the results of this research.

A comparative study of genome organization and inferences for the systematics of two large bushcricket genera of the tribe Barbitistini (Orthoptera: Tettigoniidae: Phaneropterinae).

BACKGROUND: Poecilimon and Isophya are the largest genera of the tribe Barbitistini and among the most systematically complicated and evolutionarily intriguing groups of Palearctic tettigoniids. We examined the genomic organization of 79 taxa with a stable chromosome number using classical (C-banding, silver and fluorochrome staining) and molecular (fluorescence in situ hybridization with 18S rDNA and (TTAGG)n telomeric probes) cytogenetic techniques. These tools were employed to establish genetic organization and differences or similarities between genera or species within the same genus and determine if cytogenetic markers can be used for identifying some taxonomic groups of species. RESULTS: Differences between the karyotypes of the studied genera include some general changes in the morphology of the X chromosome in Isophya (in contrast to Poecilimon). The number of major rDNA clusters per haploid genome divided Poecilimon into two main almost equal groups (with either one or two clusters), while two rDNA clusters predominated in Isophya. In both genera, rDNA loci were preferentially located in the paracentromeric region of the autosomes and rarely in the sex chromosomes. Our results demonstrate a coincidence between the location of rDNA loci and active NORs and GC-rich heterochromatin regions. The C/DAPI/CMA3 bands observed in most Poecilimon chromosomes suggest the presence of more families of repetitive DNA sequences as compared to the heterochromatin patterns in Isophya. CONCLUSIONS: The results show both differences and similarities in genome organization among species of the same genus and between genera. Previous views on the systematics and phylogenetic grouping of certain lineages are discussed in light of the present cytogenetic results. In some cases, variation of chromosome markers was observed to correspond with variation in other evolutionary traits, which is related to the processes of ongoing speciation and hybridization in zones of secondary contact. It was concluded that the physical mapping of rDNA sequences and heterochromatin may be used as an additional marker for understanding interspecific relationships in these groups and their routes of speciation.

Two new species of Hygronemobius Hebard, 1913 (Orthoptera, Grylloidea, Nemobiinae) from Brazilian Amazon.

Two new Neotropical species of Hygronemobius Hebard were described from Brazilian Amazon: Hygronemobius duckensis sp. nov. and Hygronemobius dialeucus sp. nov. Photographs of habitus, morphological characteristics and male genitalia were provided. Calling songs and spectrograms of the new species were characterized.

Species of the subgenus Cantotrella (Orthoptera: Gryllidae: Podoscirtinae: Varitrella) from Singapore, Malaysia and Indonesia.

Ten species of the subgenus Cantotrella Gorochov, 2006 belonging to the genus Varitrella Gorochov, 2003 of the tribe Podoscirtini are recorded from Singapore, Malaysia and Indonesia. Eight of them are new and described here: V. (C.) orion sp. nov.; V. (C.) trusmadi sp. nov.; V. (C.) striata sp. nov.; V. (C.) robusta sp. nov., V. (C.) sukau sp. nov., V. (C.) tawau sp. nov., V. (C.) amoena sp. nov., V. (C.) manukan sp. nov.

A new species of Cardiodactylus (Orthoptera: Grylloidea: Eneopterinae) from Singapore.

Cardiodactylus is a speciose cricket genus belonging to the subfamily Eneopterinae. One new species of Cardiodactylus from Singapore is described: Cardiodactylus admirabilis Tan & Robillard n. sp. Acoustic analysis is also performed on the male calling song. A key to species of Eneopterinae from Singapore is provided.

Endecous apterus: a new species of cave cricket from northeast Brazil, with comments on the use of subterranean habitats by Luzarinae crickets (Orthoptera: Grylloidea: Phalangopsidae: Luzarinae).

In this study we describe the first apterous species of Endecous Saussure (1878), collected in two caves at Ituaçu, Bahia State, Brazil. In Brazil, Endecous is the most widespread cricket in hypogean environments and its species can colonize caves and inhabit the entrance and the aphotic zones; Endecous species can also be found in the litter, rock gullies, crevices, burrows, and any natural cavities. The use of subterranean habitat by Endecous crickets and its related genera are discussed.

Revision of the genus Pteroplistes in India, with the description of two new species Pteroplistes kervasae Jaiswara, n. sp. and Pteroplistes masinagudi Jaiswara, n. sp. (Orthoptera, Grylloidea, Pteroplistinae).

Pteroplistes Brunner von Wattenwyl, 1873 is an Indo-Malaysian cricket genus with only one species, P. platycleis Bolivar, 1899(1900) known from India. Here, we redescribe the genus Pteroplistes and P. platycleis and describe two new Indian species, Pteroplistes kervasae Jaiswara, n. sp. and Pteroplistes masinagudi Jaiswara, n. sp. from the Western Ghats, using morphology and genitalia. Identification keys to separate the Indian species of Pteroplistes are provided and the distribution of the genus in India is discussed.

Record of Natula matsuurai Sugimoto (Orthoptera: Gryllidae: Trigonidiinae) and other sword-tailed crickets from India.

The genus Natula is a new record from the state of Rajasthan, India. Description of the species has been supported with photographs and line drawings leading to its identification. The other common sword-tailed crickets of the sub-family Trigonidiinae have also been described.