Lack of correlation between vertical distribution and carrier frequency, and preference for open spaces in arboreal katydids that use extreme ultrasound, in Gorgona, Colombia (Orthoptera: Tettigoniidae) / Falta de correlación entre distribución vertical y frecuencia portadora, y preferencia por espacios abiertos en saltamontes arbóreos que utilizan ultrasonido extremo, en Gorgona, Colombia (Orthoptera: Tettigoniidae)

Male Tettigoniidae emit sound to attract conspecific females. The sound is produced by stridulation. During stridulation the forewings open and close, but it is during the closing stroke that the scraper contacts the file teeth to generate the predominant sound components, which are amplified by adjacent wing cells specialized in sound radiation. The sounds usually exceed the sonic boundary and might occur above 40 kHz, reaching extreme ultrasonic frequencies of 150kHz in some species. Here we test the hypothesis that Tettigoniidae species should prefer microhabitats that favour efficient signal transmission, i.e. that there is a relationship of sound frequency with the vertical distribution of the species (from ground to canopy) at Gorgona National Natural Park, Colombia. We sampled 16 trees and four different altitudinal levels between 1 and 20m above the understory vegetation. We placed collecting blankets separated by vertical distances of 5m, and knocked insects down using the technique known as fogging. We found no correlation between vertical distribution and carrier frequency, but there was a preference for open spaces (below the canopy and above the understory) in species using extreme ultrasound. This is the first quantitative description of the vertical distribution in neotropical species of the family Tettigoniidae and its relationship to the calling song frequency. Rev. Biol. Trop. 62 (Suppl. 1): 289-296. Epub 2014 February 01.

Los machos de Tettigoniidae producen sonido frotando las alas anteriores para atraer a sus hembras coespecíficas con fines reproductivos (mecanismo conocido como estridulación). Un borde esclerotizado (o raspador) en el ala derecha es frotado sobre una vena modificada con dientecillos en el ala izquierda. Durante la estridulación las alas abren y cierran, pero es durante el cierre que el raspador contacta los dientecillos de la lima y produce vibraciones que son amplificadas por celdas adyacentes especializadas para radiar sonido. Sonidos que superen los 20 000Hz, se consideran ultrasónicos, en los Tettigoniidae, la mayoría de los cantos superan el umbral sónico y pueden ocurrir a más de 40 000Hz, con casos extremos de hasta 148 000Hz. La esencia de este trabajo es el estudio de esta gama espectacular de frecuencias de la familia Tettigoniidae y su relación con la distribución vertical de los individuos en las especies que habitan en Gorgona. Se muestrearon 16 árboles a cuatro niveles diferentes de altitud entre 1 y ~20m sobre el sotobosque, instalando sabanas colectoras a intervalos de 4-5m. Los insectos se colectaron mediante el método de nebulización térmica. El análisis indica que no hay correlación entre la distribución vertical de las especies y la frecuencia del canto. Sin embargo se observó una preferencia por espacios abiertos en especies que cantan a frecuencias extremas. Este estudio representa la primera descripción cuantitativa de la distribución vertical de Tettigoniidae Neotropicales y su relación con la frecuencia del canto.

Effects of shape variations on the energy metabolism of the sand cricket Gryllus firmus: a geometric morphometric analysis

Respiration and energy metabolism are key processes in animals, which are severely constrained by the design of physical structures, such as respiratory structures. Insects have very particular respiratory systems, based on gas diffusion across tracheae. Since the efficiency of the tracheal respiratory system is highly dependent on body shape, the pattern of morphological variation during ontogeny could have important metabolic consequences. We studied this problem combining through-flow respirometry and geometric morphometrics in 88 nymphs of the sand cricket, Gryllus firmus. After measuring production in each individual, we took digital photographs and defined eight landmarks for geometric morphometric analysis. The analysis suggested that ontogenic deformations were mostly related to enlargement of the abdomen, compared to thorax and head. We found that (controlling for body size) metabolic variables and especially resting metabolism are positively correlated with a shape-component associated to an elongation of the abdomen. Our results are in agreement with the mechanics of tracheal ventilation in orthopterans, as gas circulation occurs by changes in abdominal pressures due to abdominal contractions and expansions along the longitudinal axis.

Two new species of Phalangopsis Serville, 1831 (Orthoptera: Grylloidea: Phalangopsidae) from Brazilian Amazon Forest

We describe here two new species of the genus Phalangopsis Serville, 1831 from the Brazilian Amazon Forest. The male genitalia and the female copulatory papilla were described, and a combination of diagnostic characteristics was given to separate both new species from the other described species. The principal morphological characteristics of this genus were discussed.

Aqui foram descritas duas espécies novas do gênero Phalangopsis Serville, 1831 da Floresta Amazônica brasileira. A genitália masculina e a papila copulatória feminina são descritas, bem como uma combinação de características diagnósticas para separar ambas as novas espécies das outras espécies descritas. As principais características morfológicas foram discutidas.