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1 July 2014 A New North American Species of Bucrates (Orthoptera: Tettigoniidae: Conocephalinae: Copiphorini)
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Abstract

Bucrates weissmani n.sp. is known from four localities in southern Arizona. It is smaller and more slender than the other four species of Bucrates, making it superficially similar to the Central American copiphorine Caulopsis cuspidata, but more fundamental features refute the notion that it belongs in Caulopsis rather than Bucrates. Four other species of Bucrates are known. Two of these, capitatus (De Geer) and clausus (Scudder), occur in sympatry in Central America and tropical South America; lanista Rehn is known only from southern Brazil; and malivolans (Scudder) is restricted to the southeastern United States. All are easily distinguished morphologically and, for the three for which the songs are known, by their songs. Unlike the two other species of Bucrates for which the habitat is known, B. weissmani occurs on altitudinal islands at the edge of a desert. The calling song of B. weissmani resembles that of numerous species of Neoconocephalus, whereas the songs of B. malivolans and B. capitatus, resemble each other more than either song resembles that of B. weissmani.

Introduction

Coneheaded katydids (Copiphorini) are large enough and loud enough to have been detected, collected, and described wherever they occur in America north of Mexico. This paper describes a species that escaped detection until 1990 when its calling song prompted David Weissman to stop his car at 1679 m elevation on his way down Kitt Peak, Arizona. There he collected two males and a female. Independently, in 2001, Jeffrey Cole, was attracted to an unfamiliar song and collected a male at 1359 m near Madera Canyon, Arizona. In 2001, Weissman suggested that I describe his recently discovered species of conehead from Arizona. I agreed and a few months later established a species page on SINA (2001-date) under the name “Bucrates n. sp. A.” Thus when Cole consulted SINA for help in identifying the unfamiliar conehead he had collected, he contacted me about his new locality for “Bucrates sp. A” and soon sent the specimen to me for inclusion in this paper. In 2013, both Weissman and Cole returned to southern Arizona, where Weissman added a third locality for the new species, collected eight more specimens, and noted the altitudinal and ecological distributions of the species. Cole recorded and collected a male at what becomes the fourth altitudinal island the species is known to occupy.

Methods

Access to supporting materials (SM).—To improve access to the original data and the analyses that were undertaken for this paper, four tables were composed and assigned to SM. These may be accessed through hyperlinks in BioOne's “Full Text” and PDF digital versions.

Collecting sites of specimens examined.—D.B. Weissman and Jeff Cole provided specimens of the new species from the five sites listed below. Unless within brackets, [.], the data are from labels on the specimens.

  • Site #1. D.B. & B.I. Weissman (DBW stop90-52), 2 ♂♂T, 1♀, Arizona, Pima County, Kitt Peak, el. 1370–2130m, 17Jun 1990. [In 2013, DBW wrote that with a better GPS, the elevation range had been 1097 to 1913m, corresponding to mile posts 2 to 10.5, and that mp 8.7, el. 1737m and 31.9506N 111.6253W, would be a good type locality.]

  • Site #2. Jeff Cole, 1♂M, Arizona, Pima County, Proctor Rd, 2 mi W of Madera Canyon Rd, 31.741N, 110.887W, 1359m, 4–5Aug2001.

  • Site #3. D.B. & D.W. Weissman (DBW stop 13–17), Arizona, Cochise County, Ramsey Canyon Preserve, 31.4476N 110.3068W, el. 1679m, 1Jun2013.

  • Site #4. D.B. & D.W. Weissman (DBW stop 13–36), 1♂, 1♀, Arizona, Pima County, Kitt Peak, 31.9506N 111.6253W, el. 1737m, 7Jun2013.

  • Site #5. J.A. Cole & J.F. Limón, 1♂, Arizona, Cochise County, Cochise Stronghold, FR4809, [Dragoon Mountains,] 31.93949N, 109.96156W, el. 1451 m, 13Jul2013.

Calling song recording and analysis.—In a paper on the calling songs and forewing movements of a genus of conocephalines, Morris & Walker (1976) defined phonatome as “all the sound produced during one cycle of [fore]wing movement.” That term will be used here because it is appropriate to the songs described.

As detailed in  SMTable4 (SMTable4.xlsx). Weissman made five tape recordings of four B. weissmani males. The four most recent recordings were made of caged specimens at room temperatures of 24 to 28°C, using a Sennheiser ME40 microphone and a Uher 4000 Report IC recorder at a tape speed of 19 cm/s. They were later digitized at a sampling rate of 44,100 pers with a bit depth of 16. Cool Edit 2000 was used to determine phonatome rate (ph/s) from a brief sample taken from the approximate middle of each third of each of the four recordings. When the values were not identical, the median value was accepted. Peak frequency was determined in a similar fashion but with an extensive sample taken from each one third. Weissman's four 19.9 cm/s recordings are archived in Cornell's Macaulay Library of Natural Sounds ( SMTable4 (SMTable4.xlsx)). Cole made one recording of B. weissmani calling song, in the field, with a Sony digital PCM-D50 recorder with built-in microphones sensitive to 40kHz, set to sample at 96 kHz and a bit depth of 16. His recording is posted at  http://entnemdept.ifas.ufl.edu/walker/Buzz/180a.htm.

Fig. 1.

Bucrates weissmani n.sp. A. Male (holotype). B. Female (allotype). C. Male cone. D. Male face. E. Male anterior dorsum. (Photographs by Lyell Buss, University of Florida.)

f01_69.jpg

Results

Bucrates weissmani n. sp.
Weissman's Conehead

  • Holotype.— Male: Site #1 (see Methods). See Fig. 1A, C–E (in the online version of this article, the figures can be viewed at 400% without loss of resolution. They are also online at  http://www.entnemdept.ufl.edu/walker/buzz/180a.htm). Terminalia as in Fig. 2. Lengths (mm): body (including tegmina) 40, tegmina 30, pronotum 7.3, hind femur 15. Brown color form. California Academy of Science, Type No. 18493.

  • Females: Sites #1 (allotype) and #4. See Fig. 1B. Lengths: body 41, 42; tegmina 31, 32; pronotum 6.3, 6.4; hind femur 15, 15; ovipositor 14, 14. Brown and green color forms.

  •  SMTable1 (SMTable1.xlsx) has the measurements and other data for all B. weissmani specimens examined.

  • Discussion

    Generic status.—In 21 of the 22 previously known species of North American copiphorines (SINA 2014), the fastigium is separated from the frons by a sizable gap, but in Bucrates malivolans, and other members of its genus, there is no such gap ( http://entnemdept.ufl.edu/walker/buzz/s160k.htm). Instead the ventral surface of the fastigium is continuous with the frons (Fig. 1C, D). Thus if one assumes that weissmani belongs to a North American genus, Bucrates is the best choice. However, the four species already in the genus Bucrates are larger (Table 1) and, in each species, the fastigium is short compared with that of weissmani (Fig. 1E), making it prudent to consider copiphorine genera beyond the four Nearctic ones before settling on Bucrates. The list of candidate genera was expanded by the inclusion of other New World genera. Old World genera were excluded because Tettigoniidae have not been revised on a worldwide basis since the late nineteenth and early twentieth centuries (Nickle & Naskrecki 1997). This has led to species being assigned to genus on the basis of their geographic location. For example, species of coneheads that would be assigned to Neoconocephalus if native to the New World, would be assigned to Ruspolia if native to the Old World, and to Euconocephalus if native to the Indo-Australian region (Naskrecki 2000). Based on the keys, illustrations, and text of Nickle (1992) and Naskrecki (2000), B. weissmani is indeed a Bucrates. Key differences between B. weissmani and Caulopsis are indicated in  SMTable2 (SMTable2.docx).  SMTable3 (SMTable3.xlsx) gives the ranges of key measurements for all species of Bucrates.

    Table 1.

    Comparison of Bucrates species. Morphological data for capitatus and clausus are from Naskrecki (2000).

    t01_69.gif

    Relation of weissmani to other species of Bucrates.—Of the five species of Bucrates, only capitatus and clausus are sympatric. Naskrecki (2000) has described and illustrated the differences between these two, and the geographical ranges of the other three species are separated by 1200 km or more from the range of any other Bucrates species. Specifically, malivolans is separated from weissmani by ca 1200km (east Texas to south Arizona); weissmani is separated from clausus by ca 1500 km (south Arizona to Jalisco, Mexico); and lanista, from clausus and capitatus, by ca 3700 km (Porto Alegre, Brasil, to Venezuela). Table 1, which is provided instead of a key to species, compares Bucrates species and reveals that males, when known, can be identified by their terminalia and that females can be identified by combinations of morphological features.

    Calling songs.—The song of B. weissmani is a buzzy, high pitched, continuous whine produced by ca 185 wing-stroke cycles per s at 25°C.  SMTable4 (SMTable4.xlsx) lists the six known recordings and their physical characteristics. As indicated in Methods and in the SM table, digital files of these recordings are accessible online. Compared with the songs of other Nearctic coneheads, the song of B. weissmani most resembles the songs of Neoconocephalus velox and N. palustris, which have songs of similar quality and continuity with rates at 25°C of ca. 196 and 202 ph/s (SINA 2014 at  http://entnemdept.ifas.ufl.edu/walker/Buzz/198a.htm and  http://entnemdept.ifas.ufl.edu/walker/Buzz/195a.htm).

    In contrast to B. weissmani, B. malivolans produces a coarse, raspy buzz that is repeated individually or at a nearly regular rate of about 2 per second for short to medium sequences. Each buzz consists of 5 to 8 phonatomes with the intensity and duration of the successive phonatomes slightly increasing. At 25°C the phonatomes within each buzz are produced at a rate of ca 51ph/s (based on audiospectrographic analyses of 47 recorded songs as documented at  http://entnemdept.ifas.ufl.edu/walker/Buzz/181a.htm). The 6 s of song whose waveform is illustrated at that site is a sequence of 13 closely similar buzzes; the first five of these have 7 phonatomes each and the last eight have 8 phonatomes each. The last two buzzes are expanded at  http://entnemdept.ifas.ufl.edu/walker/Buzz/181ss3.htm.

    The only other species of Bucrates for which a calling song has been reported is B. capitatus. For that species Belwood & Morris (1987, Fig. 1A) show a 1.6 s audiospectrogram that includes 15 phonatomes made at a temperature within the range of 25–27°C. These closely resemble audiospectrograms of phonatomes of B. malivolans but are produced at slower rates. The first nine of the capitatus phonotomes are evenly spaced during the first 0.8 s of the sample and the last six are nearly evenly spaced during the final 0.8 s—i.e., the phonatomes seem to have been produced at discrete rates of ca 11.25 ph/s and 7.50 ph/s. This makes an average rate of 9.375 ph/s for the 1.6 s shown. Should this average continue, the number of phonatomes in 1 minute would be 563, but Belwood & Morris place the number of phonatomes per minute at 450. Thus, the 1.6 s sample they display is more densely populated with phonatomes than average. Should the two phonatome rates be the only two produced and the proportions of the two rates be the same as those in their illustration, some 12 s of silence would need to be inserted to reduce the count from 563 to 450 phonatomes. In B. malivolans, indeterminate periods of silence are often inserted between bouts of regularly spaced phonatome sequences. The songs of both malivolans and capitatus have modest phonatome rates produced with interruptions, whereas weissmani calling songs are long continued and have a much higher phonatome rate.

    Geography.Bucrates weissmani occurs in a part of Arizona that is on the eastern edge of the Sonoran Desert and has a number of small mountain ranges that rise above the predominantly treeless plains of 914 to 1219m [=3,000 to 4,000 ft. on the 1:250K Nogales USGS topographic map from which these elevations were read]. The range of elevations at which weissmani males were heard calling on Kitt Peak was 1079 to 1913 m. The elevations of the three other localities for the species (1359, 1451 and 1679 m) were within this range. Because, in the future, suitable habitats for weissmani may migrate upward, here are the maximum elevations within the four small mountain ranges known to harbor weissmani. Kitt Peak (2096 m) is part of the Baboquivari Mtns., whose highest peak is 2356 m. Madera Canyon is about 75 km ESE of Kitt Peak and is in a slope ofthe Santa Rita Mtns., whose highest peaks are 2617 and 2881 m. Ramsey Canyon Preserve is about 65 km ESE of Madera Canyon and is in a slope of the Huachuca Mtns., whose highest peak is 2885 m. The Dragoon Mtns. are about 65 km NNE of Madera Canyon; their highest peak is 2,292m.

    Ecology.—The following two paragraphs summarize what is known of the ecology of B. weissmani, taken mostly from the collecting notes of D. B. Weissman.

    Habitat/behavior.— At Kitt Peak, 7Jun2013, all males and females were on perennial bunch grasses in open, mixed grass-shrub habitat; bunches had some green blades but most blades were brown and dry. At Ramsey Canyon Preserve, 1Jun2013, two males were heard. Both were singing from bunch grasses under open tree cover. All males were captured easily because they continued to sing when approached with head lamps on.

    Fig. 2.

    Terminalia of holotypic male. The cerci are above the subgenital plate and its cylindrical styli. Each cercus has two subapical spines. The outer spine has a minimal basal piece whereas the inner spine has a substantial one (the inner spine of the right cercus is not visible in this image). (Automontage made by Lyell Buss, University of Florida.)

    f02_69.jpg

    Seasonal life history.—Available evidence suggests that B. weissmani is univoltine and has a single period of mating activity each year. Of the 22 other Nearctic species of copiphorines, six occur only at latitudes south of southern Arizona ( http://entnemdept.ufl.edu/walker/buzz/katvlist.htm#Subfamily Copiphorinae) Of the remaining 16 species, none is bivoltine, although Neoconocephalus triops may have that life cycle in southern peninsular Florida and a partial second generation as far north as South Carolina ( http://entnemdept.ifas.ufl.edu/walker/Buzz/191dlc.htm.

    Of the 16 species of North American copiphorines defined above, 14 (including Bucrates malivolans) apparently overwinter in the egg stage. The two exceptions are N. triops and Pyrgocorypha uncinata, which overwinter as diapausing adults that do not call or mate prior to undergoing diapause (Whitesell & Walker 1978; Fulton 1951). Thus, based on what is known of North American copiphorine life cycles, the egg and the diapausing adult are the two candidates for the overwintering stage of B. weissmani. As pointed out by Weissman (pers. comm. 5Feb2014), egg overwintering seems unlikely because low temperatures and occasional severe droughts during late winter and early spring would not be favorable for the survival of hatchlings and their growth to early-season adulthood. To strengthen this argument Weissman refers to the fact that North American Gryllus spp. generally overwinter either in the egg or as mid-to-late nymphal instars (Walker & Masaki 1989) and notes that of the many Gryllus spp. he has studied in the Southwest, nearly all overwinter as diapausing nymphs that mature early in the growing season. In view of nymphal diapause being unknown among North American copiphorine species, B. weissmani adults that are in reproductive diapause when they mature in the fall seem likely to be the overwintering stage for the species.

    Acknowledgements

    David B. Weissman (California Academy of Sciences) would have written this paper had he not been too busy with his studies of the genus Gryllus. As it was, he not only did most of the field work and song recording described above, he actively helped throughout the writing of this paper. Jeffry Cole (Los Angeles County Museum of Natural History) is responsible for all other field work on the species. David Nickle's (National Museum of Natural History) review significantly improved the manuscript.

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    Thomas J. Walker "A New North American Species of Bucrates (Orthoptera: Tettigoniidae: Conocephalinae: Copiphorini)," Journal of Orthoptera Research 23(1), 69-73, (1 July 2014). https://doi.org/10.1665/034.023.0101
    Published: 1 July 2014
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