Modicogryllus perplexus Otte & Cade, 1984

Felix, Rob, Bouwman, Jaap, Odé, Baudewijn, Ketelaar, Robert, Pham, Duc Minh & Bailey, James, 2025, The grasshoppers and crickets (Orthoptera) of the Socotra Archipelago (Yemen): a comprehensive overview and a description of a new Oecanthus Tree Cricket (Oecanthidae), Contributions to Entomology 75 (1), pp. 21-166 : 21-166

Modicogryllus perplexus Otte & Cade, 1984

Figs 148 , 149 , 150 , 151

References for Socotra.

Gorochov 1993: 87; Wranik 2003: 316, plate 149.

Diagnostic notes.

Modicogryllus perplexus is a medium-sized, dark-brown cricket (Fig. 148 ). It is slightly larger than Eumodicogryllus chivensis and much darker overall. It has six clear longitudinal stripes on the occiput and vertex, sometimes with a thin median line. The frons has a narrow pale line connecting the lateral ocelli. The epistomal suture is slightly curved, with an obtuse angle and a rounded apex (difference with Eumodicogryllus ). The tegmina have two harp veins.

The pseudepiphallus has the shape of a bridge (Fig. 149 ). The main lobes of the pseudepiphallus (MLPs) are thick and short, with an obtuse apex curved inwards. The pseudepiphallic parameres (PsP) are long and slender, asymmetrical in shape and length and have sharp inward curved apices. The sclerites of the epi-ectophallic invagination do not have an apodem of the transverse parameral muscle. There is a wide and long ectophallic apodeme (EctAp) at the base (Arc) of the sclerites of the epi-ectophallic invagination.

Gorochov (1993) identified material from Saudi Arabia and Socotra in the NHMUK as this species. The material we collected in 2009 and 2010 tends to be smaller with shorter tegmina than the type specimens, especially in females (Table 6 ). Wing venation and the phallic complex are identical to Otte and Cade (1984) (Fig. 149 ).

Taxonomic notes.

Otte and Cade (1984) described Modicogryllus perplexus from Transvaal, South Africa, giving a somewhat limited description in that it can only be identified by its genitalia.

Distribution and occurrence.

This species is only known from Natal and Transvaal in eastern South Africa ( Otte and Cade 1984; Otte et al. 1988), Saudi Arabia and Socotra ( Gorochov 1993). On Socotra, it is widespread (Fig. 150 ). In Oct 2010, it was abundant at Wadi Zerig, Adho Dimello and Wadi Shilhin.

Habitat and biology.

In South Africa, it is found in open grassy vegetation and around seasonally wet pans ( Otte and Cade 1984). On Socotra, the habitat seems comparable: short and wet grassy vegetation, often near water, at elevations from 50–1100 m a. s. l. Records are from January, February, April, October and November.

Bioacoustics.

The calling song of M. perplexus on Socotra consists of echemes lasting 400–450 ms and repeated at the rate of about 0.4–0.6 per second (Fig. 151 A ). Echemes consist of 22–25 syllables, repeated at 63–67 per second in the second two-thirds part, being slower and quieter in the first part (42–48 per second) (Fig. 151 B ). The carrier frequency is 5.6 kHz (5.5 kHz in the first few syllables) and has several harmonics at higher frequencies (Fig. 151 C ; XC 877950, accessible at https://www.xeno-canto.org/877950).

Otte and Cade (1984) described the sound of specimens from South Africa as short trills consisting of two parts; the first third to two-thirds consists of a simple train of pulses; the second part consists of pairs of pulses. Deducing from the information in their publication, we would describe the calling song as consisting of echemes lasting 450–650 ms and repeated at about 0.8–1.4 per second. Echemes consist of about 32–36 syllables, repeated at 58–76 per second in the first part of the echeme up to 81–107 per second in the second part of the echeme and with 4–9 pairs of syllables (with a syllable repetition rate of 61–81 per second). The carrier frequency is 5.7–7.1 kHz.

The song of Socotran specimens is similar to that of South African specimens. However, there are also apparent differences, for example, in the number of syllables in echemes and the presence of pairs of syllables. Further research is needed to explain these differences.

Figures

Figure 148. Modicogryllus perplexus Otte & Cade, 1984, male, female. A. Male; B. Female. Adho Dimello, Socotra, 31 Jan 2024 (photographs James Bailey).

Figure 149. Modicogryllus perplexus Otte & Cade, 1984, male phallic complex. Qeysoh, Socotra, 28 Feb 2009. A. Dorsal view, anterior end on top; B. Ventral view; C. Lateral view, anterior end on the left. Abbreviations: EctAp: Ectophallic Apodeme; EndC: Endophallic Cavity; MLPs: Main Lobes of the Pseudepiphallus; Ps: Pseudepiphallus; PsP: Pseudepiphallic Parameres; R: Ramus; ScEEI: Lateral Sclerotisation of the Epi-Ectophallic Invagination; SpRF 09 YE 320; Scale bar: 1 mm (photographs Yvonne van Dam and Rob Felix).

Figure 150. Distribution of Modicogryllus perplexus Otte & Cade, 1984 in the Socotra Archipelago.

Figure 151. Calling song of Modicogryllus perplexus Otte & Cade, 1984. Oscillograms (A, B) and spectrogram (C) depicting 10 s (A), 500 ms (B) and 2 s (C). Recorded at Adho Dimello, Socotra, 30 Oct 2010, 21: 21 h; RecRF 10147; SpRF 10 YE 062; XC 877950, accessible at https://www.xeno-canto.org/877950.