Bioacoustics of Neduba convexa

Distribution. Widely distributed in the northern Central Valley and Cascade Range of Northern California , extending east along the junction of the Sierra Nevada and Cascade Range to the Diamond Mountains. Habitat. Understory vegetation, tangles, and leaf litter of chaparral and mixed conifer forests. Also, in remaining northern Central Valley riparian forests. Seasonal occurrence. Specimens suggest a long summer and fall adult activity from July ( 1-VII-2000 , JA Cole, LACM) through November ( 10-XI-1948 , HP Chandler, CAS). Nymphs have been collected from early April through late August. Adult activity will commence earlier in the lower elevations of the Central Valley. Stridulatory file. (n = 8) length 3.1–3.9 mm , 106–145 teeth, tooth density 35.3 ± 2.8 (29.7–38.2) teeth/mm. Song. (n = 14) The male song is of the “zwee-zwee type with PTR 2.6 ± 0.3 s- 1 at 25 oC , MPTL 308.1 ± 51.1 ms, and PTF 14.0 ± 0.8 kHz. OPT are well developed. A distinct amplitude increase commences at the middle of each MPT . Males are nocturnal and may sing in aggregations . Karyotype. (n = 15) 2n♁ = 26 ( 2m + 22t + XtYt). T83-48, S83-119, topotype. Recognition. N. convexa can be confused with N. longiplutea distributed to the west, but the latter has a male ventral sclerite lateral process that is longer than the shaft, unlike the reverse condition in the former. To the south and north of N. convexa are N. radicata and N. cascadia , respectively, both of which have small lateral process on the male ventral sclerite. N. ambagiosa is also similar but males usually have a more conical ventral sclerite apex and that is a Coast Range species. Females may often be separated from N. longiplutea by the lack of a bifurcate subgenital plate apex, but this is variable in N. convexa . The N. radicata subgenital plate is wider than long with a deep notch, and that of N. cascadia does not have curved apical margins. The song of N. radicata to the south has a faster PTR, whereas the song of N. cascadia to the north has a slower PTR. Notes. This species has a wide range and can be locally abundant. N. convexa was probably widespread in the Central Valley riparian forests before modification of the region for agriculture. Local variation is evident. Males from the populations along the Feather River Drainage and Laufman Campground in the Diamond Mountains tend to have flatter ventral sclerite apices ( Plate 7C ) and are genetically distinct ( Figs. 3–5 ), but these populations are not reliably separable using any character. Further study may conclude that cryptic species are present along this east-west transect across the northern rim of the Central Valley and the Sierra Nevada . The physiology of this species is apparently adapted for activity at cold temperatures. On Mount Shasta, males sang between 10–15 oC . When brought into the laboratory at standard temperature, individuals became hyperactive and did not survive long (JAC pers. obs.).

Fig. 9 (distribution), Fig. 16 (male and female habitus, calling song, male and female terminalia, karyotype), Plate 4G (male calling song), Plate 7 A–C (male ventral sclerites), Plate 9H (male titillators), Plate 11G (female subgenital plate). Common name. Convex Shieldback. History of recognition. This taxon was described as a variety of N. carinata ( Caudell 1907 ) . The type series included specimens from widely separated localities in California : Mount Shasta and Napa County. We resolved the taxonomy in relation to topotypes from the Mount Shasta type locality designated by Rentz & Birchim (1968) . The North Coast Range type material from Napa County belongs to N. ambagiosa . (see species account above).