Acmaeodera plagiaticauda Horn, 1878

Westcott, R. L. & Nelson, G. H., 2000, Descriptions Of Two New Species Of Acmaeodera Eschscholtz, And Two New Subspecies Of Agrilus Curtis And Chrysobothris Eschscholtz (Coleoptera: Buprestidae) In North America, With Detailed Notes On Others, The Coleopterists Bulletin 54 (3), pp. 300-312 : 301-308

Acmaeodera plagiaticauda Horn

Acmaeodera plagiaticauda Horn 1878:10

Acmaeodera postica Fall 1899:25 , new synonymy

Acmaeodera verecunda Barr 1972:153 , new synonymy

Van Dyke (1919) discussed the considerable geographical variability of this species; however, his ‘‘... certain specimens from more desert regions, such as Bishop, California ...’’ surely are A. purshiae Fisher , to which some specimens of A. plagiaticauda bear superficial resemblance. Barr (1972) described A. verecunda , which included some of this variability. After examining approximately 450 specimens from throughout the range of these taxa, we reached the conclusion that subspecific differentiation is not warranted.

Described from ‘‘the Mariposa region of California,’’ A. plagiaticauda is best characterized as being dark purplish­coppery brown with separated lateral red elytral markings which usually extend well onto the disk, where often there are additional markings. However, the markings are extremely variable in size, number and placement; and they may be yellow, totally or in part. Some specimens, more typically those in the southern and western portions of this species’ range, bear no discal maculation. This is true on the holotype of A. postica , which has the lateral markings on each elytron reduced to a small apical pair. Southern populations usually bear yellow markings (in addition to red apical ones), and the few specimens we have seen from the northwestern part of the range tend towards having only lateral markings which are red. Some workers might argue subspecies differentiation for this species; however, in our opinion there are too many exceptions to color and pattern of markings, and too few specimens from some regions, to render it advisable.

The northernmost locality recorded for this species was in southern Douglas Co., Oregon ( Beer 1944). However, a specimen from Klamath Co., N. Rim Crater Lake, 6,700̍, 30­VII­88, on Arctostaphylos (RLWE) supplants it and is from a considerably higher elevation than any other locality known for this species. Based on the literature and specimens examined, it occurs from there throughout California in most if not all mountain ranges and foothills, except the desert, as far south as San Diego Co. and Baja California Norte: Sierra Juárez, 3.8 mi S El Condor, 9­V­81; 6 mi N Laguna Hanson, 3­VI­82; Sierra San Pedro Mártir, 1.5 mi S and 2.5 mi SE Rcho. El Burro, 1,300 m, ‘‘mid May’’ and 26­VI­83; 38 km E San Telmo, 760 m ‘‘mid May’’ (DSVC, RLWE, SDMC) [new record, Mexico]. Adults have almost always been collected on or flying over manzanita, Arctostaphylos spp. Rearing records exist from A. viscida Parry , on which the adults have been observed to feed ( Westcott et al. 1979). In the U.S. Forest Service collection at Oregon State University, there are specimens from California, Santa Clara Co., Los Gatos; and Tulare Co., Three Rivers, the Hopkins records for which state they were cut from Arbutus menziesii Pursh. However , the specimens are labeled from Arctostaphylos glauca Lindl. We are not aware of any specimens taken on Arbutus L., though the two ericaceous genera are closely related. A specimen of A. plagiaticauda from California, Napa Co., 2 mi NNE Angwin, is labeled ‘‘eating petal of garden rose’’ (CASC), and one from San Bernardino Co., Cajon Pass (GCWC) is labeled ‘‘yellow composite.’’ We are unaware of another example of flower visitation for this species.

The holotype of A. postica is labeled ‘‘Los Angeles Co., CAL./Collection Coquillett/postica.Fall. type (h)/Type No.4179 U.S. N.M. (red label)/ Acmaeodera postica Fall (h).’’ The abdomen in missing. It seems to be an aberration, much smaller than average and without discal elytral maculation, only small lateral red markings being present. The synonymy of A. postica with A. plagiaticauda necessitates our erecting the following new species. The fact that it is well known, abundantly represented in collections and highly distinctive precludes the necessity for a lengthy description.

Acmaeodera rubrocuprea Westcott and Nelson , new species Fig. 1

Acmaeodera postica: Auctorum (not Fall 1899); White 1939; Van Dyke 1919; Chamberlin 1926 (in part).

Holotype. Male, 9.00 mm long, 3.37 mm wide, flattened above, moderately elongate, moderately shining reddish copper, beneath more strongly shining coppery black; pronotum with a small red spot on each side at basal ⅓, elytra irregularly margined with red; vestiture long, mixed white and dark brown above, denser and all white below. Head coarsely reticulate­punctate, vaguely depressed just above middle, with a short distinct carina on vertex; vestiture white below, mixed with darker setae above; clypeus broadly arcuately emarginate. Pronotum coarsely densely punctate becoming more coarsely and reticulately punctate laterally, vaguely depressed at middle, more broadly and triangularly so in front of base; lateral margins explanate from apex to basal ⅓, then abruptly constricted and not visible from above. Elytra coarsely punctate, intervals roughly punctured, fifth vaguely elevated from near umbones to near apical ¼; lateral margins distinctly serrate from behind sinuation, strongly so apically; front angles weakly, triangularly produced ventrad. Ventral surface with punctures moderate in size and placement at middle, becoming much coarser and denser laterally; front margin of prosternum nearly straight, not prominent on either side of middle, strongly retracted from front angles of pronotum; last visible abdominal sternum broadly rounded, subapically not thickened, with no trace of a plate or ridge.

Material Examined. Holotype ( CASC), labeled ‘‘Sunset Val, S Barbara Co., VII­16­38 Cal/ Cercocarpus betuloides /B. E. White Collector/B.E. WHITE Collection, 1962 Gift/ HOLOTYPE Acmaeodera rubrocuprea Westcott & Nelson’’ (p, red label). Paratypes: 883 from California, Alameda Co., Cedar Mt.; Kern Co., Caliente Crk., Greenhorn Mts., Lebec; Los Angeles Co., All Nations Camp, Benedict Canyon, Beverly Glen, Big Rock Sprs., Caballero Can., Charleton Valley, Glendale, Laurel Can., Millard Can., Mt. Baldy Village, Oak Flat, Pasadena, San Vicente Mt., Sierra Madre, Tanbark Flat, Topanga Can.; Monterey Co., 5 air mi N Escondido Campground (Santa Lucia Mts., 2,800̍), Horse Bridge (1.5 air mi SW Arroyo Seco Guard Sta., 1,300̍); Orange Co., O’Neill Regional Park, Tin Mine Can.; Riverside Co., 2 mi NW Keene Camp, Pinyon Flat, Santa Rosa Mts. (Hwy. 74, 3,700̍), Thomas Camp; San Bernardino Co., Alta Loma, Cajon Jct., Cajon Pass, 3 mi S Camp Angelus, Devore, Etiwanda & vic., Lytle Crk. Can., Rancho Cucamonga, 14 mi NE Redlands, 14 mi NW & 5 mi W San Bernardino, Summit Valley, 5 mi N Upland, 7 mi ESE Wrightwood; San Diego Co., Bankhead (& vic.), Boulder Oaks, Boulevard (& vic.), Descanso, Dodge Valley, Jacumba (& vic.), Kitchen Crk., Laguna Mts. (1 mi N Hwy. 80), 5 mi W Manzanita, Pine Valley, San Diego; Santa Barbara Co., Sunset Valley; San Luis Obispo Co., La Panza Camp (12 mi NE Pozo); Tulare Co., Hot Springs; Ventura Co., Upper Ojai, Ventura. Dates of collection range from 14­IV to 29­VII. Two specimens from the following locality represent the only ones known to us from Mexico: Baja

Calif. N., Sa. de Juárez , Laguna Hanson, 1,600–1,650 m, 26­V­89, on Cercocarpus betuloides, R. L. Westcott. Paratypes are deposited in the following collections: CLBC, DSVC, FSCA, GCWC, GHNC, OSUO ( USFS Coll.) , RLWE, TCMC, SGWC, UCDC, WFBC, WFBM .

Variation. Color and size vary notably. In a sample of 475 specimens, the color of the dorsal surface varies from dark reddish cupreous to light cupreous with aeneous or, occasionally, strong greenish tints on both the pronotum and elytra, which are not always concolorous. All the specimens examined have red markings along the lateral margins of the elytra, but they are variably connected, and on a few specimens they may be yellowish along the basal half. The elytral disk also bears red maculation in 60% of the specimens, but in 26% of them it is indistinct, sometimes present only on one side. Red lateral pronotal markings were also found on 60% of the specimens examined, though sometimes confined to one side. They range in size and shape from a minute spot to covering about ⅔ of the lateral margin, beginning near the base and sometimes extending forward in attenuated form. The commonest condition (45%) is for both the pronotum and elytra to be maculate. One specimen was found with an elongate red marking on the frons. In sample of 50 males, length ranged from 7.0 to 11.0 mm (ave. 9.3 mm); in 50 females, from 8.0 to 13.2 mm (ave. 10.3 mm).

Distribution. This species appears limited to central and southern California, and northern Baja California; however, based on collection records it seems to be rare in the northern portion of its range.

Biology. Only the rosaceous shrub, Cercocarpus betuloides Nutt. ex T.&G. has been recorded on specimen labels. We have collected and reared many specimens from that plant, including a series that emerged over six years (GHNC). A specimen from Cedar Mt., Alameda Co. (OSUO) was cut live from this host on 9­X, indicating that this species overwinters as an adult. Undoubtedly C. minutiflorus Abrams is also a host. Unlike a great many in the genus, adults of A. rubrocuprea are not attracted to flowers.

Comparison. Van Dyke (1919) compared this species (as A. postica ) to A. plagiaticauda . Despite its long association with A. postica (= A. plagiaticauda ), the two are not closely related, falling into separate sections of the genus sensu Horn (1878), A. rubrocuprea being in Emarginatae, A. plagiaticauda in Sinuatae. However, A. postica was described from a unique holotype, is atypical of the species, and specimens like it can be confused into Emarginatae. Although the distinction between these species was obvious to earlier workers, apparently they failed to use Fall’s (1899) revision in studying their material. (Fall himself was hampered by having only three specimens which he considered to be A. plagiaticauda .) Therein, A. rubrocuprea , the last visible sternum of which is unmodified subapically, would key either to A. vandykei Fall or A. dohrni Horn , albeit rather unsatisfactorily. The only way to reach A. postica is to consider the ‘‘last ventral with thick subapical crest which is subangulate at middle’’ (oddly, in the original description Fall (1899) Fall described it ‘‘... with ill­defined apical crest.’’). Thus, the misidentification was born and perpetuated. Ironically, if specimens of A. plagiaticauda that bear a weakly sinuate prosternal margin are treated as Emarginatae sensu Fall (1899), they will key directly to A. postica! The closest relative of A. rubrocuprea may be A. vandykei , despite the fact there is no possibility to mistake them; the former remains a uniquely distinct species.

Etymology. From Latin ruber (red) and cuprum (copper), referring to the distinctive coloration.

Acmaeodera constrictinotum Westcott and Nelson , new species Figs. 2 , 4–5 , 8–9

Holotype. Female, 10.6 × 4.2 mm, robust, broadly flattened, black; head, pronotum and venter with strong brassy green reflection; elytra with weak greenish­blue sheen, and yellow maculation as in figure 2. Head moderately convex, shallowly depressed at middle, coarsely reticulately punctate, rather densely clothed with long dark brown setae, except shorter white setae in transverse depression behind clypeus. Pronotum twice as wide as long, distinctly wider at base than apex, widest at basal third, broadly convex, with a small moderately deep median depression at base, shallowly and obliquely depressed from prominent and deep lateral pits, vaguely and narrowly depressed behind apical margin on either side of middle. Sides distinctly constricted at base. Front margin broadly, shallowly rounded medially; hind margin subtruncate; lateral margins prominent and entirely visible from above except at base, sharply flattened, strongly and subarcuately converging to acute apical angle. Surface rather uniformly reticulate­punctate, punctures somewhat larger and deeper towards sides, larger than those of head; rather densely clothed with erect long dark­brown setae, except a few white ones at sides. Elytra subequal to width of pronotum, widest near umbones which are large and prominent, broadly shallowly transversely depressed medially, broadly obliquely depressed behind umbone; humeral angles quadrate; lateral margins slightly constricted at basal third, serrate from about middle, strongly so near apices. Surface with dark­brown setae as on pronotum; strial punctures deep, coarser laterally and basally where they are somewhat confused; discal striae becoming deeply impressed and with finer punctures apically; interstrial spaces of disk flattened, subequally wide, poorly defined basally, third prominently elevated for basal one­sixth, fifth slightly elevated on basal one­third, ninth the widest and strongly convex, tenth and eleventh convex medially; interstrial punctures mostly shallow and indistinct, except more prominent basally. Suture distinctly elevated on apical onehalf. Ventral surface rather densely clothed with long subrecumbent silky­white setae; front margin of prosternum retracted at sides, truncate laterally, broadly and shallowly emarginate medially. Abdomen rather finely and moderately punctate medially, more densely punctate laterally, punctures becoming much larger anterolaterally on first visible sternum; last visible sternum sparsely punctate on middle, evenly and rather broadly rounded at apex, subapical plate lacking. Genitalia as in figures 4 and 5.

Material Examined. Holotype ( CASC) labeled ‘‘ CALIF.San Bdno. Co., Clark Mt., 1,860–1,950 m, Sec. 33, T17N, R13E, 1/ 2­VII­1988, R.L. Westcott/ on or flying to flowers of COWANIA MEXICANA / HOLOTYPE, Acmaeodera constrictinotum, Westcott & Nelson’’ (h; red label). The locality for the following paratypes is variably labeled, but all include ‘‘Clark Mt.’’ and are from the same area in Sec. 33 as the holotype: On C. mexicana , 141 M, 31 F, 1/2­ VII­88, RLW, GHN; 30 M, 8 F, 10 unsexed, 10­VII­88, GHN, DSV, GCW; 17 M, 15 F, 1­VII­89, GCW, J. Fong; 6 M, 2 F, 16­VII­90, W. F. Barr; on Chrysothamnus nauseosus , 51 M, 13 F, 29 unsexed, 10­VII­88, GHN, DSV, GCW; 91 M, 67 F, 1­VII­89, GCW, J. Fong; 362 M, 128 F, 5­VII­90, GHN; 1 M, 22­ V­93, GHN; on Prunus fasciculata , 1 F, 2­VII­88, GHN; no host, 5 M, 2 F, 4­ VII­75, T. Griswold; 3 M, 1 F, 15/16­VI­91, J. Rifkind. 2 F on C. mexicana, Sec. 3, T 16N, R 13E, 1675 m, P. Ralidis; 25­VI­88, GHN. Paratypes in BMNH, CASC, CDAE, CLBC, DSVC, EMUS, GCWC, GHNC, NMPC, RLWE, SGWC, TCMC, USNM, WFBC, WFBM, ZMAS.

Variation. There is remarkable uniformity on the vague greenish blue tint of the elytra, with only a few specimens showing a slightly aeneous tint. To facilitate explaining the variation in elytral maculation exhibited by the holotype, a line drawing is presented ( Fig. 8 ); 353 males and 122 females were examined. In males, 26% were like the holotype, in females 67%; mark 2 is absent in 60% of males, in 28% of females; mark 3 is always present, but

divided on one female; marks 4 and 5 are always present, though 4 is divided in 33% of males, 4% of females, and 5 is divided in 13% of males, 5% of females. Size was measured on 50 of each sex, males varying from 7.2–10 mm long (ave. 9.4 mm), females from 8.4–11.6 mm long (ave. 10.4 mm). Additional variation worthy of note: The sides of the pronotum usually are distinctly, often strongly constricted at base; however, on some specimens the constriction is scarcely evident. A weakly to moderately (one specimen) developed subapical carina may be present on the last visible abdominal sternum—particularly, it seems, on the male.

With regards to distinguishing the sexes, in females the ungual tooth is smaller, extending no more than half the length of the tarsal claw, and the apex of the last visible abdominal sternum is more narrowly rounded. In males, the latter structure varies from broadly rounded to subtruncate.

Comparison. The closest known relative of A. constrictinotum is A. inyoensis Cazier ( Figs. 3 , 6–7 ), a species heretofore known only from the Panamint Range, Inyo Co., California. Specimens of the latter have been seen from Beveridge and Lead canyons, Inyo Mts., Inyo Co. (CDAE, RLWE). The most evident difference between these species can be found on the sides of the pronotum, which in A. inyoensis are not constricted at the base. However, as pointed out above, this constriction may be indistinct on some specimens of A. constrictinotum . In the latter species the lateral margins of the pronotum are almost always more broadly and extensively visible from above, particularly between the middle and the basal constriction. The ground color of A. inyoensis is black, without the greenish­blue caste which is quite evident on almost all specimens of A. constrictinotum . All specimens of A. inyoensis have at least one basal discal elytral spot, which may join the basal lateral spot, sometimes forming a fascia. The discal spot is even with or slightly anterior to the lateral spot. The basal spot is commonly absent in A. constrictinotum ; however, when present usually it is posterior to the lateral spot, never placed anterior to it, and it is not fasciate. The last visible abdominal sternum of A. constrictinotum rarely has a distinct subapical plate. In A. inyoensis usually the plate is evident, though on some specimens it is barely visible, thus similar to the odd specimen of A. constrictinotum . The aedeagus of A. constrictinotum ( Fig. 9 ) is slightly bowed upwards distally. In A. inyoensis the entire structure is distinctly bowed downward.

Biology. We first observed adults of A. constrictinotum flying to flowers of Cowania mexicana D. Don. , when they were most active between 12:30– 2 p. m. They remained active until 4: 35 p. m. One was observed feeding on a flower at 4: 40 p. m., another resting on a flower at 5 p. m. On the following day, beetles were observed to fly from 8:30 to 10:00 a.m., after which their numbers lessened until 12: 45 p. m. Emergence holes of the appropriate size and shape were observed in C. mexicana and another rosaceous shrub, Cercocarpus intricatus Wats. Another associated rosaceous plant, Fallugia paradoxa (D. Don) Endl. , is a potential host but was not examined. Although the majority of specimens, including mating pairs, were taken on Chrysothamnus nauseosus (Pall.)Britton , the fact no specimens were taken on blossoms of that plant nor were buprestid borings found therein, that it was not collected at lower elevations where C. nauseosus —but not the other two plants—occurs, and given our knowledge of related species of Acmaeodera , it seems doubtful that C. nauseosus serves as a larval host. More likely it is simply a favored site for mating aggregation. The habitat for this species appears to be pinyonjuniper woodland.

Etymology. From Latin constrictus (constricted) + notum, referring to the prothorax.

Figures

Figs. 1–3. Habitus of Acmaeodera spp. 1) A. rubrocuprea (holotype); 2) A. constrictinotum (holotype); 3) A. inyoensis.

Figs. 4–7. Ovipositors of Acmaeodera spp. 4, 5) A. constrictinotum; 6, 7) A. inyoensis.

Figs. 8–10. 8) Diagram of Acmaeodera constrictinotum; 9) male genitalia of same, lateral, dorsal and ventral; 10) male genitalia of Chrysobothris purpureovittata cercocarpi, dorsal and ventral.