Body Size Adaptations to Altitudinal Climatic Variation in Neotropical Grasshoppers of the Genus Sphenarium (Orthoptera: Pyrgomorphidae)

Altitudinal clines in body size can result from the effects of natural and sexual selection on growth rates and developing times in seasonal environments. Short growing and reproductive seasons constrain the body size that adults can attain and their reproductive success. Little is known about the effects of altitudinal climatic variation on the diversification of Neotropical insects. In central Mexico, in addition to altitude, highly heterogeneous topography generates diverse climates that can occur even at the same latitude. Altitudinal variation and heterogeneous topography open an opportunity to test the relative impact of climatic variation on body size adaptations. In this study, we investigated the relationship between altitudinal climatic variation and body size, and the divergence rates of sexual size dimorphism (SSD) in Neotropical grasshoppers of the genus Sphenarium using a phylogenetic comparative approach. In order to distinguish the relative impact of natural and sexual selection on the diversification of the group, we also tracked the altitudinal distribution of the species and trends of both body size and SSD on the phylogeny of Sphenarium. The correlative evidence suggests no relationship between altitude and body size. However, larger species were associated with places having a warmer winter season in which the temporal window for development and reproduction can be longer. Nonetheless, the largest species were also associated with highly seasonal environments. Moreover, large body size and high levels of SSD have evolved independently several times throughout the history of the group and male body size has experienced a greater evolutionary divergence than females. These lines of evidence suggest that natural selection, associated with seasonality and sexual selection, on maturation time and body size could have enhanced the diversification of this insect group

FIGURE 1 in A new discovery of a long-winged form of Mexican endemic grasshopper Melanotettix dibelonius Bruner, 1904 (Orthoptera: Acrididae: Gomphocerinae) and notes on wing polymorphism and geographic distribution

FIGURE 1. Images of live individuals of Melanotettix dibelonius. A. Long-winged male. B. Short-winged female. C. Longwinged male (parasitized with acari). D. Short-winged male. E. Long-winged female. F. Short-winged male. Photos by SSU, BF & MEP.Published as part of Mariño-Pérez, Ricardo, Sanabria-Urbán, Salomón, Foquet, Bert, Pocco, Martina E. & Song, Hojun, 2020, A new discovery of a long-winged form of Mexican endemic grasshopper Melanotettix dibelonius Bruner, 1904 (Orthoptera: Acrididae: Gomphocerinae) and notes on wing polymorphism and geographic distribution, pp. 515-524 in Zootaxa 4838 (4) on page 519, DOI: 10.11646/zootaxa.4838.4.5, http://zenodo.org/record/440544

FIGURE 2 in A new discovery of a long-winged form of Mexican endemic grasshopper Melanotettix dibelonius Bruner, 1904 (Orthoptera: Acrididae: Gomphocerinae) and notes on wing polymorphism and geographic distribution

FIGURE 2. Images of mounted individuals of Melanotettix dibelonius. A. Long-winged male lateral. B. Short-winged male lateral. C. Long-winged male dorsal. D. Short-winged male dorsal. E. Long-winged female lateral. F. Short-winged female lateral. G. Long-winged female dorsal. H. Short-winged female dorsal.Published as part of <i>Mariño-Pérez, Ricardo, Sanabria-Urbán, Salomón, Foquet, Bert, Pocco, Martina E. & Song, Hojun, 2020, A new discovery of a long-winged form of Mexican endemic grasshopper Melanotettix dibelonius Bruner, 1904 (Orthoptera: Acrididae: Gomphocerinae) and notes on wing polymorphism and geographic distribution, pp. 515-524 in Zootaxa 4838 (4)</i> on page 520, DOI: 10.11646/zootaxa.4838.4.5, <a href="http://zenodo.org/record/4405441">http://zenodo.org/record/4405441</a&gt

FIGURE 3 in A new discovery of a long-winged form of Mexican endemic grasshopper Melanotettix dibelonius Bruner, 1904 (Orthoptera: Acrididae: Gomphocerinae) and notes on wing polymorphism and geographic distribution

FIGURE 3. Updated geographic distribution of Melanotettix dibelonius and its two morphotypes identified (red triangle = longwinged form; blue circle = short-winged form). Numbers beside the symbols indicate the locality number. *Asterisk denotes localities from which specimens were measured for the morphological analyses.Published as part of <i>Mariño-Pérez, Ricardo, Sanabria-Urbán, Salomón, Foquet, Bert, Pocco, Martina E. & Song, Hojun, 2020, A new discovery of a long-winged form of Mexican endemic grasshopper Melanotettix dibelonius Bruner, 1904 (Orthoptera: Acrididae: Gomphocerinae) and notes on wing polymorphism and geographic distribution, pp. 515-524 in Zootaxa 4838 (4)</i> on page 521, DOI: 10.11646/zootaxa.4838.4.5, <a href="http://zenodo.org/record/4405441">http://zenodo.org/record/4405441</a&gt

Studies in Mexican grasshoppers: Four new species of Reyesacris Fontana, Buzzetti & Mariño-Pérez, 2011 (Orthoptera: Acrididae: Ommatolampidinae)

Four new species of Reyesacris Fontana, Buzzetti & Mariño-Pérez, 2011 are described from Southern Mexico (Guerrero and Oaxaca States). Reyesacris zihua sp. nov., R. atoyacensis sp. nov., R. mephaa sp. nov. and R. tika sp. nov. A dichotomous key to species of Reyesacris and distribution map are provided together with an analysis of external and internal male genitalia to place this genus in the subtribe Vilernina within the tribe Ommatolampidini.Fil: Mariño Pérez, Ricardo. University of Michigan; Estados UnidosFil: Sanabria Urbán, Salomón. Universidad Nacional Autónoma de México; MéxicoFil: Pocco, Martina Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Foquet, Bert. Illinois State University; Estados Unidos. Texas A&M University; Estados UnidosFil: Song, Hojun. Texas A&M University; Estados Unido

A new discovery of a long-winged form of Mexican endemic grasshopper Melanotettix dibelonius Bruner, 1904 (Orthoptera: Acrididae: Gomphocerinae) and notes on wing polymorphism and geographic distribution

The species Melanotettix dibelonius Bruner, 1904 was previously recorded from Michoacán and Guerrero states in Mexico. This species is characterized by its tegmina, which are always shorter than head and pronotum together and sometimes shorter than the pronotum. After recent field expeditions (2015-2019) and an extensive review of museum specimens from the most important Orthoptera collections in Mexico and USA (291 specimens), we discovered a long-winged form of this species south of its previous known range, which effectively expanded its distribution range into Oaxaca state. We discuss some aspects regarding the patterns of geographic distribution and morphological variation among the long-winged and short-winged morphs. We conduct statistical analyses and observed that on average, the tegmina of long-winged individuals (both females and males) are slightly longer than twice the length of pronotum; whereas in short-winged individuals the tegmina are nearly as long or slightly longer than the length of the pronotum. Moreover, on average, females appear to have longer tegmina than males in both morphotypes. We provide photographic records of both forms live and mounted, the most comprehensive distribution map to date and a discussion of evolutionarily interesting patterns found in this species.Fil: Mariño Pérez, Ricardo. University of Michigan; Estados UnidosFil: Sanabria Urbán, Salomón. Universidad Nacional Autonoma de Mexico. Facultad de Estudios Superiores de Iztacala; MéxicoFil: Foquet, Bert. Texas A&M University; Estados UnidosFil: Pocco, Martina Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Song, Hojun. Texas A&M University; Estados Unido

Phylogeny based on a concatenated Bayesian analysis of the total genetic evidence retrieved from 67 <i>Sphenarium</i> and 15 outgroup taxa.

<p>Tip labels indicate current taxonomic classification, voucher numbers and locality ID for all included terminals, except for those whose genetic information was retrieved from GenBank (*). Black vertical bars indicate the phylogenetic position of the identified species based on our integrative taxonomy approach (names and coloured symbols in front of the black bars).</p

Parsimony ancestral reconstruction of the altitudinal distribution of the <i>Sphenarium</i> species performed in MESQUITE v. 3.0.2 [79].

<p>For this analysis we used the species tree analysis topology and the mean elevation values estimated for each species.</p

Consensus species tree of the 18 identified taxa of <i>Sphenarium</i>.

<p>The consensus species tree (in black) is embedded in all sampled trees (in blue) of the Markov Chain Monte Carlo chain of the species tree analysis including the total genetic evidence obtained from <i>Sphenarium</i> and <i>Prosphena</i> individuals. Higher tree densities represent high levels of certainty. Numbers before the nodes indicate posterior probabilities values. G1, Monophyletic Group 1; G2, Monophyletic Group 2; G3, Monophyletic Group 3.</p

Sampling localities of <i>Sphenarium</i> (L1-L63) included in this study and geographic distribution of the 18 identified species within the genus.

<p>This map is based on the digital elevation model developed for Mexico, including only the Mexican states where the genus <i>Sphenarium</i> is distributed.</p