Oxyecous lesnei Chopard, 1935

Naskrecki, Piotr & Guta, Ricardo, 2019, Katydids (Orthoptera: Tettigoniidae) of Gorongosa National Park and Central Mozambique, Zootaxa 4682 (1), pp. 1-119 : 83

Oxyecous lesnei Chopard, 1935

http://lsid.speciesfile.org/urn:lsid: Orthoptera .speciesfile.org:TaxonName:11093

( Figs. 36 A–G, 54G–I)

Diagnostic remarks. A medium-sized katydid that exhibits a distinct sexual dimorphism. Males have long, nearly translucent tegmina and hind wings that surpass the tip of the abdomen by over half their length whereas in the female the wings surpass the tip of the abdomen by only about a fifth of their length ( Figs. 36D, E ). Males of O. lesnei are easily identifiable by the presence of conspicuous cuticular folds (auriculae) on the inner sides of the tympana; these folds are much smaller but still noticeable in the females. The costal and median fields of the male tegmen have reduced venation, resulting in large, membranous areas in the proximal half of the wing ( Fig. 36A ).

Bioacoustics. O. lesnei , along with Debrona cervina Walker, 1870 , are unique among known katydids in being able to stridulate in flight. This interesting behavior, its mechanism, and potential adaptive advantage will be discussed in an upcoming publication (Naskrecki, in prep.). The in-flight stridulation usually has a different temporal pattern than the stationary stridulation, which the males engage in later at night. While stationary on tall bushes and lower branches of trees, the males produce long series of single syllables every 0.38– 0.60 s, which are occasionally followed by a short series of 2-syllable echemes; mean syllable duration is 0.067 s (SD=0.0267, n=44); the peak frequency of the call is 5.9–7.6 kHz ( Figs. 54 G–I), making it easily audible from a distance of several meters.

Distribution and natural history. Originally described from Mozambique, O. lesnei has been recorded also from the Democratic Republic of the Congo, Zambia, Zimbabwe ( Ragge 1956b), Malawi, and South Africa (material examined). In Mozambique it has been recorded from the Tete, Manica, and Sofala provinces. This species is associated primarily with tall miombo woodlands, from low elevations to about 900 m a.sl. In Mozambique and South Africa adults are seen only during a relatively narrow period between March and early May when the humidity is high. During that time males can be seen flying at dusk along forest edges and above the canopy, whereas flightless females can be seen on low vegetation.

Measurements (3 males, 3 females).: male 45–49 (46.32.3), female 36–38 (371);: male 22–24 (231), female 20–24 (22.32.1);: male 8–9 (8.3.6), female 7–8 (7.7.6);: male 32–35 (33.71.5), female 28–29 (28.3.6);: male 24–25 (24.7.6), female 21–24 (231.7);:, female 9–10 (9.7.6) mm.

Material examined (39 specimens). Malawi: Lengwe National Park , elev. 170 m (-16.26667, 34.65), 28.iii.1986, coll. Otte, Glenn & Ruffin (170)— 1 male ( ANSP) ; Mozambique: Manica, near Vila Pery [Chimoio], region du mont Malenge ( Vandouzi ), (-19.1, 33.4), 1–31.iii.1928, coll. M.P. Lesne— 1 male (holotype) ( MNHN) ; Sofala, Coutada 12, along road, (-18.223932, 35.299300), 25–26.iii.2017, coll. P. Naskrecki— 1 male ; Coutada 12, Inhamitanga Forest, Camp 1, elev. 210 m (-18.23835, 35.33015), 9–14.iv.2018, coll. P. Naskrecki— 3 males ; Cheringoma, Coutada 12, Chironde camp, elev. 156 m (-18.32780, 35.35799), 25.iii.–4.iv.2017, coll. P. Naskrecki, J. Guyton & M. Castene— 1 female, 1 male ; Coutada 12, main road to Marromeu , elev. 250 m (-18.22393, 35.29930), 26.iii.2017, coll. P. Naskrecki (Flysong)— 1 male ; same locality, 26.iii.2017, coll. P. Naskrecki (A13)— 1 male ; Coutada 12, road to Marromeu , elev. 218 m (-18.21613, 35.31432), 28.iii.2017, coll. P. Naskrecki— 1 male ; Coutada 12, road to railway, elev. 201 m (-18.30323, 35.33324), 29.iii.2017, coll. P. Naskrecki & J. Guyton— 7 males ( EOWL) ; Nhagutua , road to ranger station, elev. 269 m (-18.68283, 34.81786), 19.iv.2013, coll. P. Naskrecki— 1 female ( MCZ) ; nr. Codzo ( Khodzue ), cave and nearby, elev. 216 m (-18.564, 34.872222), 14–25.iv.2017, coll. P. Naskrecki— 1 female, 2 males ( EOWL) ; Gorongosa , GNP, Bela Vista ranger outpost, elev. 26 m (-18.69470, 34.20853), 5–12.v.2015, coll. P. Naskrecki— 3 females, 4 males ( EOWL, MCZ) ; GNP, Bunga Inselberg, Camp 1, nr. Bunga ranger outpost, elev. 75 m (-18.59989, 34.33686), 21.iv.–5.v.2015, coll. P. Naskrecki— 2 males ( EOWL, MCZ) ; GNP, Mt. Gorongosa , campsite above Murombodzi Waterfall , elev. 943 m (-18.482953, 34.044936), 30.iii.2018, coll. P. Naskrecki— 1 male ; Gorongosa Dist., Between Bunga camp and Bunga inselberg, elev. 139 m (-18.59973, 34.34301), 21.iv.–5.v.2015, coll. P. Naskrecki and R. Guta— 1 male ( EOWL) ; Tete, Songo (accampamento), Cahora Bassa , (-15.5958333, 32.7647222), iii.1974, coll. M.C. Ferreira & G.V. Ferreira— 1 male ( UEMM) ; same locality, iv.1973, coll. M.C. Ferreira & G.V. Ferreira— 1 male ( UEMM) ; Republic of South Africa: KwaZulu Natal, Lake Sibaya, Baya Camp , (-27.38333, 32.66667), 24.i.1990, coll. S. van Noort— 1 male ( SAMC) ; Tongaland, Manzengwenya, Lake Sibaya , (-27.29722, 32.70111), 5–7.v.1976, coll. H.D. Brown— 1 male ( SANC) ; Zambia: Chongwe , (-15.359431, 28.446256), 14.v.2015, coll. W. van Niekerk— 1 male ; Zimbabwe: Lundi , (-20.8994444, 30.7861111), 13–16.iii.1964, coll. Vari & van Son— 1 male ( TMSA) .

Figures

FIGURE 36. Mozambican Oxyecous spp.: A. Oxyecous lesnei, male right tegmen; B. ditto, male abdominal apex, dorsal view; C. ditto, male subgenital plate; D. ditto, male, lateral view; E. ditto, female, lateral view; F. ditto, ovipositor; G. ditto, male head and pronotum, dorsal view; H. O. magnus, male, lateral view; I. ditto, ovipositor; J. ditto, male head and pronotum, dorsal view; K. ditto, male abdominal apex, lateral view.

FIGURE 54. Oscillograms and power spectra of Mozambican Phaneropterinae: A–C. Gonatoxia helleri; D–F. Debrona cervina, stationary call; G–I. Oxyecous lesnei, stationary call; J–L. O. magnus.