Substrate-borne vibration in Pacific field cricket courtship displays

While thought to be widely used for animal communication, substrate-borne vibration is relatively unexplored compared to other modes of communication. Substrate-borne vibrations are important for mating decisions in many orthopteran species, yet substrate-borne vibration has not been documented in the Pacific field cricket Teleogryllus oceanicus. Male T. oceanicus use wing stridulation to produce airborne calling songs to attract females and courtship songs to entice females to mate. A new male morph has been discovered, purring crickets, which produce much quieter airborne calling and courtship songs than typical males. Purring males are largely protected from a deadly acoustically orienting parasitoid fly, and they are still able to attract female crickets for mating though typical calling song is more effective for attracting mates. Here, we document the first record of substrate-borne vibration in both typical and purring male morphs of T. oceanicus. We used a paired microphone and accelerometer to simultaneously record airborne and substrate-borne sounds produced during one-on-one courtship trials in the field. Both typical and purring males produced substrate-borne vibrations during courtship that temporally matched the airborne acoustic signal, suggesting that the same mechanism (wing movement) produces both sounds. As previously established, in the airborne channel, purring males produce lower amplitude but higher peak frequency songs than typical males. In the vibrational channel, purring crickets produce songs that are higher in peak frequency than typical males, but there is no difference in amplitude between morphs. Because louder songs (airborne) are preferred by females in this species, the lack of difference in amplitude between morphs in the substrate-borne channel could have implications for mating decisions. This work lays the groundwork for investigating variation in substrate-borne vibrations in T. oceanicus, intended and unintended receiver responses to these vibrations, and the evolution of substrate-borne vibrations over time in conjunction with rapid evolutionary shifts in the airborne acoustic signal.

Nosema locustae (Protozoa, Microsporidia), a Biological Agent for Locust and Grasshopper Control

Effective locust and grasshopper control is crucial as locust invasions have seriously threatened crops and food security since ancient times. However, the preponderance of chemical insecticides, effective and widely used today, is increasingly criticized as a result of their adverse effects on human health and the environment. Alternative biological control methods are being actively sought to replace chemical pesticides. Nosema locustae (Synonyms: Paranosema locustae, Antonospora locustae), a protozoan pathogen of locusts and grasshoppers, was developed as a biological control agent as early as the 1980s. Subsequently, numerous studies have focused on its pathogenicity, host spectrum, mass production, epizootiology, applications, genomics, and molecular biology. Aspects of recent advances in N. locustae show that this entomopathogen plays a special role in locust and grasshopper management because it is safer, has a broad host spectrum of 144 orthopteran species, vertical transmission to offspring through eggs, long persistence in locust and grasshopper populations for more than 10 years, and is well adapted to various types of ecosystems in tropical and temperate regions. However, some limitations still need to be overcome for more efficient locust and grasshopper management in the future.

Integrative taxonomy confirms that Gregarina garnhami and G. acridiorum (Apicomplexa, Gregarinidae), parasites of Schistocerca gregaria and Locusta migratoria (Insecta, Orthoptera), are distinct species

Orthoptera are infected by about 60 species of gregarines assigned to the genus Gregarina Dufour, 1828. Among these species, Gregarina garnhami Canning, 1956 from Schistocerca gregaria (Forsskål, 1775) was considered by Lipa et al. in 1996 to be synonymous with Gregarina acridiorum (Léger 1893), a parasite of several orthopteran species including Locusta migratoria (Linné, 1758). Here, a morphological study and molecular analyses of the SSU rDNA marker demonstrate that specimens of S. gregaria and specimens of L. migratoria are infected by two distinct Gregarina species, G. garnhami and G. acridiorum, respectively. Validation of the species confirms that molecular analyses provide useful taxonomical information. Phenotypic plasticity was clearly observed in the case of G. garnhami: the morphology of its trophozoites, gamonts and syzygies varied according to the geographical location of S. gregaria and the subspecies infected.

Composition of the intestinal nematofauna of Anurogryllus muticus and Neocurtilla claraziana (Orthoptera) from pastures of La Plata city, Buenos Aires, Argentina

The present study analyzes the intestinal nematofauna of the orthopteran species Anurogryllus muticus and Neocurtilla claraziana as part of a survey work conducted in pastures from the region of La Plata to isolate entomopathogenic nematode species. Eleven nematode species belonging to the families Thelastomatidae, Travassosinematidae, Cephalobidae, Rhabditidae, and Plectidae are reported. Parasitism percentages from 0.31 to 22.71 % were observed being Blatticola cristovata and Cephalobellus magalhaesi the most prevalent species. Cephalobium nitidum, Cruznema tripartitum, and Plectus parietinus are reported for the first time from Argentina. The findings of the study contribute to a better understanding of the biodiversity status of insect parasitic nematodes of the region.

Mandibular Structure, Gut Contents Analysis and Feeding Group of Orthopteran Species Collected from Different Habitats of Satoyama Area within Kanazawa City, Japan

A study was conducted on assemblies of various orthopteran species from distinct habitats in the Satoyama region, Kanazawa City, Ishikawa Prefecture, Japan, and a total of 50 distinct orthopteran species were registered. These species were represented by 10 families and were belonged to 17 subfamilies and 27 tribes. Results based on stereo-microscopic examination of the mandibular morphology and the analysis of gut contents suggested seven proposed feeding groups for these collected orthopteran species. Among the examined subfamilies, family Tettigoniidae proved to be the most diverse in mandibular structure and four feeding groups were assigned. This was followed by family Acrididae, which showed three feeding groups. Other families contained only single feeding group. It was noted that only five species, from family Acrididae, were graminivorous with their mandibles characterized by comparatively very short incisors and relatively wide molar regions. The analysis of gut contents of these five species proved to contain more than 80% monocotyledonous plant species. Predation and scavenging as feeding habits were also recorded in some orthopteran species.

New taxa and notes on palm and false-leaf katydids (Orthoptera: Tettigoniidae: Mecopodinae, Sexavaini; Pseudophyllinae, Cymatomerini) from Brunei Darussalam

As many as 72 species were documented when sampling was conducted in Kuala Belalong in Brunei Darussalam between 2016 and 2017 but this remains non-exhaustive and orthopteran species are still awaiting discovery. Based on new material collected in 2019, two new species of katydids are described here: Segestes nostosalgos sp. n. and Sathrophylliopsis mentham sp. n. These two discoveries are of particular interest: Segestes nostosalgos sp. n. represents the first record of the tribe Sexavaini in Borneo; Sathrophylliopsis mentham sp. n. is drastically different from congeners by the lack of dense fine long hairs around the body.

Response of orthopterans to macroclimate changes: A 15-year case study in Central European humid grasslands

Orthoptera is a good indicator taxon of macroclimate changes. In our case study, we analyzed data of orthopterans, vegetation, and macroclimate collected yearly from 2002 through 2017 in Central European humid grasslands. During the study period, the annual mean temperature increased, while the relative abundance of moderately hygrophilic orthopteran species decreased significantly. On the other hand, the species richness and diversity of the assemblages increased due, mostly, to an increase of graminicole/thermophilic species. According to our results, the conservation of the hygrophilic orthopteran assemblages of Central European humid grasslands under global warming can only be ensured by adequate land management, which can at least mitigate the effects of climate change resulting in the warming and drying of humid habitats.

The first annotated checklist of Croatian crickets and grasshoppers (Orthoptera: Ensifera, Caelifera)

The first annotated checklist of crickets and grasshoppers (Orthoptera) of Croatia is presented. With 184 orthopteran species, 103 Ensifera and 81 Caelifera, known to inhabit the country, Croatia is among the richest European countries in terms of Orthoptera diversity. Altogether 25 species erroneously reported from the country are omitted from the checklist, 16 Ensifera (Isophya speciosa, Poecilimon brunneri, P. jonicus, P. thoracicus, Modestana ebneri, Pachytrachis bosniacus, Rhacocleis neglecta, Tessellana carinata, T. nigrosignata, Zeuneriana marmorata, Pteronemobius lineolatus, Myrmecophilus acervorum, M. ochraceus, Dolichopoda palpata, Diestrammena asynamora, Troglophilus brevicauda) and 9 Caelifera (Tetrix kraussi, Paracaloptenus caloptenoides, Chorthippus albomarginatus, Omocestus viridulus, Pseudochorthippus montanus, Miramella alpina, Celes variabilis, Oedipoda germanica, O. miniata). First faunistic records of 10 taxa are reported for Croatia, in total four Ensifera (Leptophyes punctatissima, Metrioptera hoermanni, Zeuneriana amplipennis, Gryllotalpa sp.) and six Caelifera (Xya variegata, Chorthippus dichrous, C. loratus, C. mollis ignifer, Odontopodisma sp., Acrotylus l. longipes). For each listed species, its distribution in Croatia and in Europe is given, and IUCN European Red List status is shown for species within threatened categories. Numerous distributional, taxonomic and nomenclatural problems are discussed. Several taxa with poorly defined diagnostic traits are synonymized, namely Gampsocleis abbreviata renei syn.nov. (with G. a. abbreviata), Pholidoptera maritima syn.nov. (with P. dalmatica), P. brachynota syn.nov. (with P. dalmatica), Acrida m. mediterranea syn.nov. (with A. u. ungarica), Chrysochraon dispar intermedius syn.nov. (with C. d. giganteus) and Odontopodisma rammei syn.nov. (with O. fallax).

B Chromosomes in Grasshoppers: Different Origins and Pathways to the Modern Bs

B chromosomes (Bs) were described in most taxa of eukaryotes and in around 11.9% of studied Orthopteran species. In some grasshopper species, their evolution has led to many B chromosome morphotypes. We studied the Bs in nine species (Nocaracris tardus, Nocaracris cyanipes, Aeropus sibiricus, Chorthippus jacobsoni, Chorthippus apricarius, Bryodema gebleri, Asiotmethis heptapotamicus songoricus, Podisma sapporensis, and Eyprepocnemis plorans), analyzing their possible origin and further development. The studied Bs consisted of C-positive or C-positive and C-negative regions. Analyzing new data and considering current hypotheses, we suggest that Bs in grasshoppers could arise through different mechanisms and from different chromosomes of the main set. We gave our special attention to the Bs with C-negative regions and suggest a new hypothesis of B chromosome formation from large or medium autosomes. This hypothesis includes dissemination of repetitive sequences and development of intercalary heterochromatic blocks in euchromatic chromosome arm followed by deletion of euchromatic regions located between them. The hypothesis is based on the findings of the Eyprepocnemis plorans specimens with autosome containing numerous intercalary repeat clusters, analysis of C-positive Bs in Eyprepocnemis plorans and Podisma sapporensis containing intercalary and terminal C-negative regions, and development of heterochromatic neo-Y chromosome in some Pamphagidae grasshoppers.