Brachys howdeni Hespenheide, 1833

Hespenheide, Henry A. & Eiseman, Charles S., 1833, A New Species ofBrachysDejean, 1833 (Coleoptera: Buprestidae) from the Eastern United States Using an Unusual Host, The Coleopterists Bulletin 1833 (2), pp. 335-340 : 335-340

Brachys howdeni Hespenheide , new species ( Fig. 1 )

Description. Holotype male: Angulate-ovate, more abruptly narrow in front than behind; black, moderately shining, head and pronotum with weak golden-coppery reflections, elytra with purplish reflections; head with rather long, pale, golden setae which are sparser and pointed obliquely laterally on vertex, denser and pointed ventrally on lower 1/3 of front between eyes; pronotum sparsely covered with long, pale golden setae except for small, round glabrous areas on both sides of midline at middle; elytra with irregular transverse fasciae of mixed silvery and pale coppery setae at base, before middle, at apical 3/4, and at apices; ventral surface with uniform, sparse, short, silvery setae ( Fig. 1 ); length 3.50 mm, width 1.75 mm.

Head 0.90 mm wide, distinctly depressed along midline, more broadly so between eyes; epistomal width 1/4 of distance between antennal depressions.

Pronotum strongly convex in cross section, nearly flat in lateral view, transversely depressed along base lateral to midline, widest at base; sides narrowly rounded at base then very weakly rounded to apical angles; with strong, weakly commashaped prehumeral carinae for about 1/2 length of pronotum at middle; surface sparsely ocellatepunctate along margins. Scutellum transversely rhomboidal, about 2X wider than long.

Elytra slightly wider than pronotum at base and widest at middle; humeri moderately prominent, each elytron with slight depression at base interior to humerus and carinate along lateral margin almost to apex; surface moderately densely, irregularly punctate, punctures denser in setal fasciae and sparser in small linear areas between fasciae.

Venter faintly, inconspicuously shagreened and ocellate punctate. Apex of terminal abdominal ven- trite broadly, shallowly rounded-truncate. Aedeagus 1.05 mm long, darkened portions of parameres narrowing slightly for basal 3/5, apical 2/5 with narrow transparent phalanges, aedeagus obtusely rounded.

Allotype female: As male, except head with coppery setae on vertex, front weakly shagreened with obliquely oval glabrous areas interior to middle of eyes and sparse, short, silvery setae elsewhere, slightly denser above epistoma; apex of last abdominal ventrite broadly rounded and more or less weakly emarginate with about 4 nearly obsolete blunt deflexed teeth on each side of emargination; length 3.70 mm.

Type Specimens. H o l o t y p e: M a r y l a n d: [Charles County,] Nr. Nanjemoy, H. Howden, Adult on Feb 3, [19]55, Raised from [Trailing] Arbutus leaf ( CMNC). Allotype: Same data as holotype ( CMNC).

Paratypes: Maine: Waldo Co., Lincolnville , Ducktrap River, coll. 05.10.2013, em. 16- 20.04.2014, C. S. Eiseman, ex Epigaea repens #CSE1084 (2 males, CSEC, USNM) . Maryland: Same data as holotype, but Adult on Feb 6, [19] 55 (female, FMNH) . Massachusetts: Franklin Co., Shutesbury , coll. 11.01.2012, em. 18.04.2012, C. S. Eiseman, ex Epigaea repens (male, female, AMNH) , Sunderland, Mt. Toby , coll. 15.09.2013, em. 16- 20.04.2014, C. S. Eiseman, ex Epigaea repens #CSE1085 (4 males, female, BMNH, CHAH, FMNH, CSEC, MCZ) , Sunderland, Mt. Toby along rd. near summit, coll. 20.03.2012, em. 27.04- 01.05.2012, C. S. Eiseman, ex Epigaea repens (male, female, CSEC) , Northfield , Northfield Mtn., coll. 01.09.2013, em. 22.04.2014, C. S. Eiseman, ex Epigaea repens #CSE1093 (male, USNM) , Northfield , Crag Mtn., coll. 11.10.2013, em. 15.04.2014, C. S. Eiseman, ex Epigaea repens #CSE1080 (male, MCZ) , Hampshire Co., Northampton, River Rd. , 500 m S of Williamsburg, coll. 18.04.2012, em. 06.05.2012, C. S. Eiseman, ex Epigaea repens (male, CHAH) , South Hadley , Bare Mountain, coll. 12.04.2014, em. 18.05.2014, C. S. Eiseman, ex Epigaea repens #CSE1112 (female, BMNH) , Nantucket Co., Nantucket, Milestone Rd , by milestone 4, coll. 20.05.2012, em. 31.05.2012, C. S. Eiseman, ex Epigaea repens (female, USNM) , Worcester Co., Hubbardston , New Templeton Rd., coll. 13.03.2012, em. 16- 18.04.2012, W. Howes, ex Epigaea repens (male, 3 females, CHAH, CSEC, MCZ, USNM) . Michigan: Crawford Co., Grayling, 25.05.1957, G. H. Nelson, Larva found mining leaves of Trailing Arbutus , larva pupated 17.08.1957 at Loma Linda, CA, emerged 23.08.1957 (female, FSCA) .

Other Specimens Examined. Maine: [ Oxford Co.], Paris , 5.07.1945, C. A. Frost, on Corylus rostrata (4, USNM) , 13.07.1949, C. A. Frost, on Corylus rostrata , 9572 CAF ’49 ( FSCA) . Massachusetts : “ Mass”, [J. N. Knull Collection] ( FMNH) ; [Berkshire Co.], No. Adams , 4.07.1920, J. O. Bridwell, mating on Crataegus (12, USNM) . New Hampshire : [Hillsborough Co.], Antrim, 13.06.1932, N. M. Downie Colln. (3, FMNH) . New Jersey : “N.J.” ( AMNH) . “ New Jersey ” (2, AMNH) ; [Camden Co.], Atco, 6.07., G. M. Greene ( USNM) ; Ocean Co., 6 mi N Warren Grove at Chamberlin Branch , 9.06.1979, W. E. Steiner ( USNM) , Mt. Misery , Lebanon State Pk., 13.05.1949, M. A. Cazier ( AMNH) . New York : “N.Y.” ( FSCA) ; [Albany Co.], Karner , 17.07.1920, “ N.Y.S. Coll. ” ( USNM) ; [Orange Co.], West Point 10.06.1908, W. Robinson ( USNM) ; Seneca Co., Willard,0.6.1970, Dr.Lenczy ( USNM) . Pennsylvania : [Carbon Co.], Lehigh Gap, 26.06.1903, G. M. Greene ( USNM) ; [Centre Co.], B[lack] Moshannon , 13.06.1948, S. W. Frost ( FMNH) ; [Dauphin Co], Hummeltown , 20.06.[year], J. N. Knull ( FMNH) ; Monroe Co., Canadensis , 7, 16.07.1926, 8, 9.07.1927, Shoemaker Collection (4, USNM) . Rhode Island : Watch Hill, 30.06.1909, W. Robinson ( USNM) .

Etymology. Named in honor of the noted coleopterist, the late Henry F. Howden, who first reared this species.

Larval Host. Epigaea repens (Ericaceae) . Additionally, adults have been collected on Corylus rostrata Aiton (= Corylus cornuta Marshall ) ( Betulaceae ) and mating on Crataegus sp. (Rosaceae) .

Discussion. Brachys howdeni is closely related to B. aerosus , but differs in having the elytra with purple reflections and with four irregular fasciae of pale silvery or coppery setae over most of the length of the elytra, and rows of setae connecting the medial and subapical fasciae. In B. aerosus reared by CSE from hosts in the Fagaceae sympatric with B. howdeni in Massachusetts, the elytra are usually more or less strongly dark metallic blue and often have few setae on the basal 2/3 of the elytra, although this varies considerably in other parts of its range (Hespenheide, personal observation). There is usually a subapical fascia of dense setae that are more or less dark golden (rarely even orange in some specimens from Georgia), often with a narrow band of silvery setae on the anterior margin. Females of B. howdeni differ in having nearly obsolete teeth on the terminal abdominal ventrite, whereas those of B. aerosus are well developed and usually 12 in number. Because variation in B. aerosus is still under study, paratypes of B. howdeni are limited to reared specimens. Brachys howdeni suggests B. aeruginosus in appearance in the relatively uniform vestiture on the elytra, but it is broader and larger in size. Although other reared and field-collected eastern species of Brachys have female-biased sex ratios, the 24 reared specimens of B. howdeni have a nearly 1:1 sex ratio (13 males, 11 females). Male specimens measure 3.30–4.00 mm long (mean = 3.66 mm, n = 11); female specimens measure 3.65–4.05 mm long (mean = 3.88 mm, n = 10).

In my (HAH) experience with species from North and Central America, male genitalia in the genus Brachys tend not to be very distinctive. In America north of Mexico, many species share genitalia similar to that of B. howdeni with transparent apical phalanges on the parameres, namely, B. aerosus , B. barberi , B. cephalicus ( Nelson 1980, fig. 3), B. floccosus , B. floricola , B. ovatus , B. rileyi , and B. tesselatus , as well as several Mexican species, all apparently associated with oaks as larval hosts. In contrast, in females the apical margin of abdominal ventrite 5 differs more widely in shape among species, usually with a row of deflexed teeth that differ in size, number, and arrangement, and, in some cases with subapical depressions bordered by elongate setae.

Biology. Occupied mines in E. repens leaves were observed and collected by CSE between 7 January 2012 and 12 April 2014. As observed by Weiss and Nicolay (1919) in other Brachys species , the egg is deposited singly on the upper surface of a leaf, and its clear, flat, shining shell, approximately 1 mm in diameter, is still visible long after hatching ( Fig. 2 ). Eggs were located on 20 of the 29 mined leaves that were examined. One of the leaves had two eggs and one had three, but no leaf ultimately produced more than one adult. Of the 23 eggs, 16 were in the basal third of the leaf, five were in the middle third, and two were in the apical third. Eight were within 1 mm of the midrib, 16 were within 3 mm, and all were within 8 mm. In a single instance, the egg was decorated with 12 minute, pale brown fecal pellets.

Upon hatching, the larva ( Figs. 3, 4 ) mines directly into the leaf, in some cases filling the egg shell with stringy frass. Larvae probably begin hatching in late July in New England; 3 August is the earliest date mining larvae were observed. The mine begins as a broad (1–3 mm wide), meandering track that follows and is bounded by either the midrib or leaf margin upon reaching one or the other. This early portion of the mine is usually obliterated by later feeding. Ultimately, the mine mostly follows the leaf margin, with the undulating inner margin of the mine typically 6–10 mm from the margin but sometimes extending all the way to the midrib, thus occupying an entire half of the leaf ( Fig. 5 ). The completed mine may occupy 60–100% of the leaf’ s perimeter and 50–100% of its area. Occasionally, on a larger leaf, the mine extends along only about half of the perimeter and one third of the surface. With one exception, in which the apical centimeter or so of the leaf had been eaten by another insect, all completed mines crossed the midrib, and all did so at the tip of the leaf (occasionally deviating from the margin by a few millimeters).

The mine is more or less full depth, all of the parenchyma being consumed, but the margin tends to be more distinct on the upper surface. In reflected light, the mine appears brown and opaque, not easily distinguished from browning at the edges of the leaves that occurs for other reasons. However, when backlit the dark frass is plainly visible, generally concentrated in irregular masses or in lines along the edges of the mine. Frass is in the form of elongate pellets or short strips when fresh, becoming granular or powdery with age.

The larva overwinters in the mine, pupating in the spring. About a month later, the adult beetle chews an irregular exit hole in the underside of the leaf, 1.5–2.5 mm by 2.0– 4.5 mm ( Fig. 6 ). The process takes at least several hours and in one case was observed to take over 24 hours. One closely monitored individual was collected as a larva on 12 April, pupated on 17 April, and emerged from the mine on 18 May. Most emergence dates were artificially early due to the leaves having been brought indoors; the Nantucket specimen, collected on 20 May and emerging on 31 May, perhaps represents the only rearing without a premature pupation and emergence. Brachys howdeni is clearly univoltine.

To investigate George Vogt’ s report (personal communication to HAH) that adults of this species feed on oak foliage, on 27 April 2012, CSE put several of the beetles in a bag with a sampling of leaves that were available in the immediate vicinity of the E. repens patch on Mt. Toby where the beetles had originated. In addition to freshly picked E. repens leaves, the leaves included red oak ( Quercus rubra L.), mountain laurel ( Kalmia latifolia L., Ericaceae ), lowbush blueberry ( Vaccinium angustifolium Aiton , Ericaceae ), Canada mayflower ( Maianthemum canadense Desfontaines , Asparagaceae ), beech ( Fagus grandifolia Ehrhart , Fagaceae ), striped maple ( Acer pensylvanicum L., Sapindaceae ), red maple ( Acer rubrum L.), and maple-leaved viburnum ( Viburnum acerifolium L., Adoxaceae ). Flowers of E. repens and bluets ( Houstonia caerulea L., Rubiaceae ) were also included. No feeding was observed until 4 May, at which point the beetles began to feed on both the E. repens and the oak leaves with no apparent preference. The beetles were kept until 14 May, and there was no evidence of feeding on any of the other material. As mentioned above, adults have been collected on Crataegus sp. and on C. rostrata in New England.

Evidence of adult feeding on both E. repens and oak is like that of other Brachys species on oak and other leaves (as illustrated by Weiss and Nicolay 1919). The leaf is chewed all the way through, always from the margin, forming elongate, irregular, sometimes branching channels approximately 2 mm wide ( Fig. 7 ).

No parasitoids emerged during CSE’ s rearings of B. howdeni , but many aborted mines were encountered. On 1 September 2013, some of these were collected at Northfield Mountain, and four eulophid wasps emerged between 4 and 21 September. Three were females of the endoparasitoid Neochrysocharis diastatae (Howard) , two emerging from a single mine. The fourth was a male ectoparasitoid in the genus Pnigalio Schrank. Christer Hansson (personal communication) reported that very small specimens such as this one lack certain characters that are necessary for species-level identification. Both N. diastatae and Pnigalio have broad host ranges, although this is the first record of the former from a buprestid (Noyes 2014). Parasitoid specimens were deposited in the collection of the Department of Zoology, Lund University, Lund, Sweden (MZLU).

Epigaea repens is evidently an underexploited host plant, as no other insect has been reported mining its leaves. The only chrysomelid reported by Clark et al. (2004) in association with it is Epitrix cucumeris (Harris) , in a long list of atypical records for this normally Solanaceae-feeding beetle. Just two lepidopteran species are known to feed on E. repens (Robinson et al. 2002) . Chambers (1881) did not explicitly describe the feeding damage caused by larvae of Aroga epigaeella (Chambers) (Gelechiidae) , but stated that they “hibernate under a silken web, and in feeding, sometimes the side of a leaf is curled over, and sometimes several leaves are fastened together by the web.” Bearberry ( Arctostaphylos uva-ursi (L.) Spreng., Ericaceae ) is the primary host plant for caterpillars of the frosted elfin ( Callophrys polios (Cook and Watson) , Lycaenidae ), which feed on the buds and flowers, but eggs and larvae have also been found on E. repens (Layberry et al. 1998) . Some E. repens leaves examined at our collection sites had small skeletonized patches on the undersides, generally near but never at the leaf margin; occasionally, small holes were eaten all the way through. The identity of the insect responsible for this damage remains a mystery.

Figures

Figs. 1–7. Brachys howdeni. 1) Dorsal view of adult; 2) Egg; 3) Early instar in mine; 4) Larva; 5) Mines in leaves of Epigaea repens; 6) Newly eclosed adult eating its way out of a mine; 7) Adult feeding damage on E. repens leaf.