The little walking leaves from Iguazú National Park (Ne Argentina) - Comparisons between subtropical and tropical <i>Typophyllum</i> species (Orthoptera: Tettigoniidae: Pterochrozinae)

Abstract

In the woods around the famous Iguazú Waterfalls were discovered numerous individuals of a little walking leaf identified as <i>Typophyllum inflatum</i>, a species long ago described from Bolivia, and apparently never reported again. So far this population represents the southernmost known record of katydids comprising the leaf-mimicking family group Pterochrozinae or Pterochrozini. Males of <i>T. inflatum</i> produce a continuous low-ultrasound pure-tone song, which could reveal the presence of this species in other areas with suitable habitat. This song is astonishingly similar to that of <i>T. erosifolium</i>, an allopatric species distributed in northwestern South America. <i>Typophyllum inflatum</i> shares with other <i>Typophyllum</i> species the pre-copulatory riding of the tiny male on the much bigger female, but this occupies only a few hours compared to up to several days in a species from Ecuador. This could be related to a possibly lower predation pressure in the subtropical region. The same may be true of the lower variability of body color, unless this only reflects adaptation to a drier environment. In contrast to tropical species, <i>T. inflatum</i> in northeastern Argentina most likely is seasonal, with adults probably appearing during the south-hemispherical summer.