Latest Articles from Journal of Orthoptera Research Latest 2 Articles from Journal of Orthoptera Research https://jor.pensoft.net/ Fri, 29 Mar 2024 08:22:37 +0200 Pensoft FeedCreator https://jor.pensoft.net/i/logo.jpg Latest Articles from Journal of Orthoptera Research https://jor.pensoft.net/ Sexual dimorphism in the badlands cricket (Orthoptera, Gryllinae, Gryllus personatus) https://jor.pensoft.net/article/93513/ Journal of Orthoptera Research 32(2): 119-126

DOI: 10.3897/jor.32.93513

Authors: Esperance M. Madera, Kevin A. Judge

Abstract: Sexual dimorphism (SD) is a common phenomenon in sexual species and can manifest in a variety of ways. Sexual size dimorphism (SSD) is commonly investigated, but it can be confounded with sexual shape dimorphism (SShD) if multivariate measures of size are not used. Univariate studies may also overestimate the prevalence or direction of SSD when the sexes are strikingly different in shape, which may be an issue in taxa such as Orthoptera and other terrestrial arthropods where maximum body size is strongly constrained. Here we tested for the occurrence of both SSD and SShD in the badlands cricket Gryllus personatus (Orthoptera, Gryllinae). We measured four body size dimensions—maxillae span, head width, pronotum length, and mean hind femur length—and used multivariate methods to test whether male and female adult badlands crickets were sexually dimorphic in size and/or shape. All the univariate dimensions were sexually dimorphic, with males having wider heads and maxillae than females and females having longer pronota and hind femora than males, which indicates SShD. However, multivariate methods failed to detect SSD, instead confirming that the sexes primarily differ in body shape. We show how a simple ratio of head width to pronotum length captures SShD in badlands crickets and apply it to iNaturalist, a citizen science platform, to broaden our findings. We propose that orthopterists studying SD minimally measure head width, pronotum length, and hind femur length as a standard that will allow a more repeatable and generalizable assessment of the prevalence and direction of both SSD and SShD.

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Research Article Mon, 12 Jun 2023 18:02:11 +0300
Allometric effect of body size and tegmen mirror area on sound generator characters in Euconocephalus pallidus (Orthoptera, Tettigoniidae, Copiphorini) from Singapore https://jor.pensoft.net/article/81126/ Journal of Orthoptera Research 31(2): 191-196

DOI: 10.3897/jor.31.81126

Authors: Ming Kai Tan

Abstract: Acoustic communication, including allometry of secondary sexual traits and body size, can differ among katydid species from different parts of the world. However, Neotropical species tend to be better studied than their Southeast Asian relatives. This is true for the tribe Copiphorini (Orthoptera, Tettigoniidae). To allow for future comparative studies of Neotropical and Palaeotropical Copiphorini, the allometric relationships between sound generator characters and body size of Euconocephalus pallidus from Singapore were examined. Five sound generator characters–tegmen length, stridulatory file length, tooth width, teeth density, and mirror area–were correlated with pronotum length as the proxy for body size. Stridulatory file length, tooth width, and teeth density were also correlated with the mirror area. The relationships were subsequently tested for difference between scaling slope and isometry based on 29 male adults from a single population. All sound generator characters except teeth density exhibited significant positive correlations with pronotum length, whereas teeth density exhibited significant negative correlation with pronotum length. Among them, only tooth width and teeth density scaled hyperallometrically, while the other characters scaled isometrically. As males produce a continuous buzzing call over long durations, larger teeth (i.e., larger tooth width and lower teeth density to accommodate larger teeth) are probably more resistant to age-related abrasion. This may imply that males with larger teeth can produce calls recognized and/or favored by the females over a longer part of the males’ adult lifespan. File length and mirror area exhibited isometric scaling. This suggests a stabilizing selection driven by their function in dictating carrier frequency, which females tend to rely on to recognize conspecific males.

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Research Article Tue, 1 Nov 2022 14:01:45 +0200