J. Crop Prot. 2021, 10 (1): 1-18________________________________________________________ Review Article Variation, plasticity and possible epigenetic influences in species belonging to the tribe Gomphocerini (Orthoptera; Gomphocerinae): A review Seyed Hossein Hodjat and Alireza Saboori* Jalal Afshar Zoological Museum, Department of Plant Protection, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. Abstract: Environmental conditions can cause variation in morphology, behavior, and possibly epigenetic in the numerous species of the Gomphocerinae, especially in mountain habitats. Plasticity and changes in morphology in many of the species in this subfamily is caused by character segregation through the female choice of copulation that has produced various clines, sub-species or species groups. The variation and plasticity, as a result of environmental stress, besides morphology, affect physiology and epigenetics of many insect species. Environmental stress and female assortative mating might be accompanied by hybridization in populations, resulting in character divergence and speciation after a long period of time. Contemporary evolution and/or epigenetic inheritance may be a reason for their variation in acoustic and morphology of Gomphocerinae and the main factor in the present situation of difficulty in their classification. We review possible effects of environmental stress on plasticity, hybridization, and speciation by the appearance of endemic species. About half of the insect pest species have reduced their impacts as pests under global warming. The present insect pest situation in Iran is discussed. Keywords: Classification, Hybridization, Groups, Gomphocerini, Phenotype, Downloaded from jcp.modares.ac.ir at 8:44 IRST on Saturday September 25th 2021 Song 1. Introduction12 2002; Mol et al., 2003; Tishechkin and Bukhvalova, 2009; Vedenina and Helversen, Geographical distribution of Gomphocerinae 2009; Şirin et al., 2010, 2014; Stillwell et al., species is the source for variation, plasticity, 2010; Vedenina and Mugue, 2011). Therefore and hybridization by environmental effects. morphology alone is not enough to define many Many endemic species and subspecies are species of Gomphocerini and taxonomists are created by acoustic divergence and sympatric using sound characteristics for identification. speciation. The degree and direction of a trait is Biodiversity studies of Gomphocerinae species related to sexual dimorphism and female choice are difficult due to a lack of knowledge for for copulation in insects (Robinson and Hall, accurately identifying them in Iran without recording their songs and considering other factors causing variation in their populations Handling Editor: Ali Asghar Talebi (Sultana et al., 2013; Hodjat et al., 2019). __________________________ More than 81 species of Gomphocerini * Corresponding author: [email protected] Received: 16 September 2019, Accepted: 14 August 2020 grasshoppers are widely distributed in the world Published online: 03 October 2020 (Sergeev, 2011). In other words, Gomphocerini 1 Factors influencing the tribe Gomphocerini___________________________________________ J. Crop Prot. is an assemblage of several similar grasshopper behavior regulated by corpora cardiac genera including Gomphocerus, Myrmeleotettix, secretion (Heinrich et al., 2012). Chorthippus, Pseudochorthippus, Stauroderus, Populations in various species of and Aeropedellus (Jago, 1971; Defaut, 2011, Gomphocerini may change their characteristics 2012, 2017). The genus Chorthippus has 229 by choosing different selection routes. species and is divided into 2 or 3 subgenera Differentially fixation of various characters on Chorthippus (Altichorthippus) (20 species), the population of a species may increase their Chorthippus (Chorthippus) (32 species), and for adaptation and survival chance. The process of various authors (including orthoptera species file divergence in colour, morphology, and song in OSF), Chorthippus (Glyptobothrus) (57 species). Pseudochorthippus parallelus (Zetterstedt) The other species of Chorthippus are not produces different traits by genetic classified into any subgenera. The Chorthippus polymorphism (Kohler et al., 2017). A long (Glyptobothrus) biguttulus group has 12 species separation of their population increases their and C. binotatus group has two species. The genetic distance, colour and morphological or genus Pseudochorthippus Defaut, 2012 with four acoustic diversification (Tregenza et al., 2000; species and two sub-species is closely related to Butlin and Hewitt, 2008; Vedenina and Mugue, Stenobothrus Fischer and Omocestus Fieber 2011; Monge, 2017). Subspecies and species (subtribe Stenobothrina). group formations are the results of genetic or Character changes in Gomphocerini species epigenetic changes in Gomphocerini (Smith and are a reaction to environmental factors that its Ritchie, 2013; Noguerales et al., 2016), through stress may have influenced their genetics, assortative mating and environmental epigenetics and external morphology (Laiolo et conditions (Klapper and Reinhold, 2003; al. 2013). Neurohormones regulate all life Burggren, 2017). processes in Gomphocerinae and insects in Rapid character divergence of grasshoppers general (Perica-mataruaga et al., 2006; Hodjat, in response to the male songs for copulation 2006). Juvenile hormones (JHs) and the and other environmental factors are influencing neurosecretory neurons (NSNs) secretions of taxonomists to clarify their classification. A corpora cardiac (CC), corpora allata (CA) and new line of research on sound production, the brain (CNS) release methylsulfonylmethane epigenetic, and stress has proved its influence (MSM) into the haemolymph. The gene on the Gomphocerinae species radiation expression is involved in C. biguttulus (L.) (Franzke and Reinhold, 2012). We refer to Downloaded from jcp.modares.ac.ir at 8:44 IRST on Saturday September 25th 2021 biogenic amines and chitin-binding. some publications of research on species Transcriptomic methods of profiling show radiations creating endemic forms by differential expression pattern in various stages phylogenetic, taxonomic, stress and genetic or of C. biguttulus life cycle and are described by epigenetic investigations (Pravdin, 1969; Mark, Berdan et al. (2017), and Tatsuta and Butlin 1983; Hodjat et al., 2018; Burggren, 2018; (2001). Gene expression pattern in C. Riede, 2018). albonemus change when pastures have been overgrazed in cases of food shortage (Qin et al., 2. Phylogeny and classification difficulties 2017). The increased activity in locust is Orthoptera Species File (OSF) has provided a list initiated after adipokinetic neurohormones are of 20 tribes classified in the Gomphocerinae secreted (Hodjat, 2016). The reaction to subfamily. Gomphocerini Fieber, 1853 or acoustic communication in response to Chorthippini Shumakov, 1963 with 16 genera is environmental conditions has been studied in C. among the largest group of grasshoppers biguttulus (Klappert and Reinhold, 2003). (Cigliano et al., 2018). Some investigations have Species in the Chorthippus (Glyptopothrus) placed Gomphocerini, Chrysochraontini, group communicate by special male songs to Dociostaurini, and Arcypterini in the phylogenetic fend off competitors from the female, a structures of Gomphocerinae and included 2 Hodjat and Saboori _______________________________________________ J. Crop Prot. (2021) Vol. 10 (1) Omocestus, Myrmeleotettix, Stenobothrus, Shestakov (2014); Vedenina et al. (2001, Chorthippus and Arcyptera in their phylogenetic 2007b). Hybridization of C. albomarginatus tree (Vedenina and Mugue, 2011; Garcia-Navas et and C. oschei produces asymmetric populations al., 2017; Rohde et al., 2017). and reduces the hybrid viability (Vedenina et Considerable phenotypic plasticity is a major al., 2007a). The founder effect of the source of difficulty in developing a unique population with different songs can establish phylogenetic classification for Gomphocerini sibling species and new cline (Helversen and (Song, 2005; Zhang et al., 2013; Şirin et al., 2014; Helversen, 1997). The main driving force of Defaut, 2017). Morphological characters of a few speciation in this group of species is sexual species in Chrysochraontini, Arcypterini, selection by the female choice of courtship. Locustinae, Acridinae, Melanoplinae, Calliptaminae and Cyrtacanthacridinae tribes or 2. 2. Chorthippus (Glyptobothrus) biguttulus subfamilies are close to Gomphocerinae or species group and subgroup overlapping in some morphological characters Habitat segregation, character diversification by (Defaut, 2017). The most common phylogenetic the female choice of copulation, and hybridization method of their separation is by the NADH are known to have established many similar (nicotine amid adenindinuclrotide phosphate) species in this group or subgroup of species mitochondrial analysis. Yet, with this method, the (Saldamando et al., 2005; Gottsberger 2007; Şirin relative time of appearance of Ramburiellini, et al., 2010; Gomez and Dyck, 2012). The Dociostaurini, and Arcypterini could not be complex C. biguttulus group is formed by a determined. However, it was estimated that the mixture of macropterous and brachypterous forms Gomphocerini and species in Stenobothrus, in occidental and central Europe (Ingrisch, 1995). Myrmeleotettix, Omocestus, Stenobothrus, and Many species in this group share habitat with C. Stauroderus genera are closely related (Defaut, binotatus binotatus (Charpentier)