Pachysmopoda abbreviata (Taschenberg, 1883)

Figs 208, 209, 210, 211

References for Socotra.

Taschenberg 1883: 184–185 [as Mecopoda abbreviata]; Karsch 1886: 108, 109, 114–115, plate IV, fig. 2 [as Mecopoda (Pachysmopoda) abbreviata]; Burr 1903: 412, 421–422; Krauss 1907: 17, 25–26, 29, plate II: figs 8, 8 ª; Uvarov (in Uvarov and Popov (1957)): 362–363; Popov 1981: 120, plate 3; Wranik 1998: 158, 161, 171; Wranik 2003: 314, plates 145, 148.

Diagnostic notes.

The size, appearance and loud song make Pachysmopoda abbreviata an unmistakable bush-cricket (Fig. 208). It is the largest bush-cricket on Socotra, characterised by a reddish-brown or green colour, a sturdy and robust body, broadly rounded and heavily-veined tegmina dotted with little cream spots and larger black ones, the latter as an extension of a black line starting at the anterior edge of the pronotum below the lateral carinae. Hind knees are also black.

Distribution and occurrence.

It is a widespread endemic to Socotra (Fig. 210), locally common in well-vegetated habitats, for example, Wadi Ayhaft, but also occurring in more open vegetation.

Habitat and biology.

P. abbreviata occurs in various vegetated habitats from 10–1470 m a. s. l. It is primarily nocturnal, hiding under stones during the day (Krauss 1907). In Feb 2009, we found it singing at night at Wadi Ayhaft from various herbs, shrubs and trees, like Senna socotrana, Buxus hildebrandtii and Jatropha unicostata (Fig. 212). Field observations indicated that a recording of the song played can sometimes trigger song responses from nearby males.

Records of both adults and nymphs (Fig. 209) are from all months. Most records of nymphs are from the last quarter of the year. The only adults on the 2010 trip were present in October at Adho Dimello. That year, we found no adults at other sites like Wadi Ayhaft, where they were numerous in February 2009.

In 2009, an elytron was found under a stone at Dixam, next to the skin of Monocentropus balfouri Pocock, 1897, suggesting Pachysmopoda is preyed upon by this spider.

Bioacoustics.

The loud, far-carrying calling song of Pachysmopoda abbreviata is an echeme, repeated irregularly, lasting 600–1200 ms (Fig. 211 A). Echemes consist of 15–27 syllables of equal duration, repeated at about 23 per second. The first few syllables are quieter than the following ones (Fig. 211 B). The main frequencies of the song are between 9.5 and 21 kHz (Fig. 211 C) (XC 877963, accessible at https://www.xeno-canto.org/877963).