Bioacoustics of Neduba diabolica

Fig. 9 (distribution), Fig. 13 (male and female habitus, calling song, male and female terminalia, karyotype), Plate 4D (male calling song), Plate 6F (male ventral sclerite), Plate 9E (male titillators), Plate 11D (female subgenital plate). Common name. Mount Diablo Shieldback. History of recognition. Originally described in Tropizaspis from a female taken at “Monte Diablo, California ” ( Scudder 1899 ). Rentz & Birchim (1968) assigned the majority of South Coast Range Neduba populations to this species and synonymized variety picturata ( Scudder 1899 ) under this name. We reassign all other South Coast Range populations to N. carinata . The type of picturata was collected during the Northwestern Boundary Survey ( Caudell 1907 ), which makes picturata a synonym of N. steindachneri (see discussion under that species) and not N. diabolica .

Distribution. Known only from Mount Diablo at the north end of the Diablo Range, California . Not known from Mt. Hamilton, also in the Diablo Range, some 67 km southeast of Mt. Diablo where N. oblongata occurs. The Vallecitos Valley is a possible biogeographic break between these two species (See N. oblongata species account above). Habitat. Oak woodland and chaparral habitats. Males call from the interior of large bushes, especially in canyon bottoms. Seasonal occurrence. Adults have been taken from late June ( 27-VI-2008 , JA Cole, W Chatfield-Taylor, W Ericson, LACM) to September ( 1-IX-2002 , DB Weissman, CAS). Nymphs were collected 7-VI-1967 ( Rentz & Birchim 1968 ). Stridulatory file. (n = 4) length 3.0– 3.5 mm , 132–145 teeth, tooth density 43.2 ± 4.5 (37.7–48.3) teeth/mm. Song. (n = 12) The song of N. diabolica consists of bouts of uniform rate “lisping” as in N . carinata . PTR 10.8 ± 0.7 s- 1 is identical to N. carinata . PTF 13.3 ± 2.3 kHz; a high frequency lab recording measured PTF at 19.2 kHz. PTdc 80.4 ± 8.0% is significantly higher than that found in N. carinata songs (ANOVA, P = 2.36 ×10 -3 ). PTdc is a temperature-invariant song character (linear regression, P = 0.188), and thus can be compared among recordings that lack temperature control. Males are nocturnal singers. Bout length is variable, but the bouts of N. diabolica males tend to be shorter and more even in length than those of N. carinata males. Karyotype. (n = 4) 2n♁ = 26 ( 2m + 22t + XtYt) T90-12, S90-61, topotype. This corrects the information of Ueshima and Rentz (1979) . Recognition. The high stridulatory file tooth density (37–48) is shared only with N. carinata in the Carinata Group. The ventral sclerite is narrow with a high convex to pyramidal apex and a poorly developed anterolateral process. In contrast, ventral sclerites of N. oblongata have a low convex apex and a minute lateral process. Except for N. radicata , all other Convexa Clade taxa have long anterolateral processes. The female subgenital plate is pentagonal and flat as in N. carinata and N. oblongata , but those two species lack a distinct medial groove, which is present in this species. Songs of N. diabolica males are qualitatively similar to those of N. carinata but have a higher duty cycle. The distribution is restricted to the vicinity of Mount Diablo, California . Notes. This species exhibits a mosaic of characters. DNA places N. diabolica with the Convexa Clade, the song type and stridulatory file are like those of N. carinata , and the genitalia resemble those of N. radicata . Mount Diablo has remained above sea level since the early Miocene ( Bartow 1991 ) and lies at the junction of the distributions of the southern Carinata and northern Convexa Clades. The mixture of characters found in N. diabolica suggests past introgression. By maintaining its species status, we recognize that N. diabolica is a phylogenetically distinct, philopatric lineage that inhabits an ancient region of high endemism and provided it remains protected (Mount Diablo is a California State Park), this lineage may persist into the future with its mixture of characters. The name picturata Scudder was originally described to differentiate insects with a mottled color pattern as opposed to uniform or striped coloration. These color pleomorphisms are shared by all species in the Carinata Group.