Ernoporus parvulus ( Eggers, 1943 )

Johnson, Andrew J., 2021, Another new exotic bark beetle in Florida: Ernoporus parvulus (Eggers, 1943) (Coleoptera: Curculionidae: Scolytinae), with additional taxonomic changes, Zootaxa 4991 (1), pp. 185-191 : 186-190

Ernoporus parvulus ( Eggers, 1943)

( Figs. 1A–B , 2A–H, 2J–L )

Margadillius parvulus Eggers, 1943: 75 .

Ernoporus parvulus ( Eggers, 1943) : Johnson et al. 2020 a: 56.

Allothenemus minutus Bright & Torres, 2006: 400 .

Ernoporus minutus ( Bright & Torres, 2006) : Johnson et al. 2020 a: 56. syn. nov.

Allothenemus exquisitus Bright, 2019: 105 .

Ernoporus exquisitus ( Bright, 2019) : Johnson et al. 2020 a: 56. syn. nov.

Type material examined. MOZAMBIQUE • 1 ♀ Lectotype Margadillius parvulus Eggers, 1943 . “Zembeze”, “Nova chomupanga pres Chemba” [Mozambique, Sofala Province, Marromeu District, Chupanga] [label not directly transcribed]; Naturhistorisches Museum Wien, Vienna , Austria.

DOMINICAN REPUBLIC • 1 ♀ Holotype Allothenemus exquisitus Bright, 2019 ; La Altagracia, “DOMINI- CAN REPUBLIC // Prov. La Altagacia // Nisbon, “Papagallo”, 16-19-VI-98// R.Woodruff-P. Freytag // Blacklight trap ” ( FSCA).

Other material examined. UNITED STATES • 3 ♀♀, 4 ♂♂; Florida, Pinellas County, Fort De Soto; 27.6313°N,- 82.7238°E; 28 Apr. 2021; A. J. Johnson leg.; ex. Talipariti tiliaceum ; Walking on recently snapped branch; UFFE:36836 • 1 ♂; Florida, Pinellas County , Fort De Soto ; 27.6313°N,- 82.7238°E; 29 Apr. 2021; Andrew J. Johnson leg.; ex. Talipariti tiliaceum ; under bark of twigs; dissected; UFFE:36823 • 1 ♀; Same collection data; imaged and DNA destructively extracted; UFFE:36821 • 1 ♂; Same collection data; imaged and DNA destructively extracted; UFFE:36822 • 9 ♀♀, 16 ♂♂ Same collection data; labeled : “ USA: Florida: Pinellas Co. // Fort De Soto , 27.6313°N, // - 82.7238°E; 2021-Apr-29 // ex. Talipariti tiliaceum //twigs. A. J. Johnson coll.” (point mounted and distributed to USNM, FSCA, DPI synoptic collection, and UFFE) .

PUERTO RICO • 1 ♀, [photo presented in Bright, 2019, no collection data] ; 1 ♂; Arecibo, Arecibo, Site 12, EDRR, 18.45271, -66.59809, 20.VI-3.VII.2013, C. Torres and H. Rivera (A.J. Cook Arthropod Research Collection, Michigan State University) [Specimen briefly examined by AJJ, November 2014; Photographs by Mark Smith, macroscopicsolutions.com re-examined, and label data from Bright 2019] .

SOUTH AFRICA • 30; KwaZulu-Natal, Mtunzuni; - 28.96°N, 31.77°E; 29 Oct. 2019; Francois Roets leg.; ex. Talipariti tiliaceum ; FR-0; UFFE:33597; ( UFFE) • 1; KwaZulu-Natal, Mtunzuni; - 28.9567°N, 31.7719°E; 31 Oct. 2019; Andrew J. Johnson leg.; ex. Hibiscus tiliaceus [= Talipariti tiliaceum ]; UFFE:36817; ( UFFE).

Diagnosis: Female. Length 0.9–1.1 mm, 2.0 times as long as wide. Frons mostly convex, with a weakly concave area in the middle and a small fovea. Antennae with three funicle segments, 1st about the same size as the 2nd and 3rd combined. Antennal club flat, slightly longer than wide. Antennal sutures weakly procurved, evenly distributed across outer surface (downward facing surface in living beetles). The last (most apical) suture is marked by dense, short setae.

Anterior margin of pronotum with four serrations, the median pair slightly larger. Three concentric rows of asperities on the pronotum, the first and second row often broken into two or three concentric groups. Pronotal summit with a short concentric row or irregular oval of contiguous asperities. Lateral margin of pronotum rounded. Pronotum with some scale like setae, especially along basal margin and along median of pronotal disc. Hypomeron with sparse hair-like setae.

Elytral disc approximately one half of elytral length. Elytral striae visible as rows of shallow punctures and strial setae. Interstrial bristles scale-like, 1.0–2.5 times as long as wide, spaces about the same distance as between rows on elytral disc, and to about half of the distance on the declivity. Very few, often none, scale-like setae in interspaces on declivity (interstrial ground vestiture). Declivity with small, barely discernable granules above each interstrial and strial seta. Protibiae with 3 or four equally sized denticles on the outside edge, on the apical third. Setae on protarsi fine hair-like, bifid at end ( Fig. 2E ).

Male. Very similar to female except with a concave frons, at about the upper level of eyes, fovea missing from middle, cuticle on upper parts of the frons strigose. Pronotum similar except anterior pronotal margin slightly more forward projected, and spacing from margin to first row larger than on female. Protibiae with feather-like setae ( Fig. 2F ). Proventriculus ( Fig. 2G ) typical of genus with short, unarmed apical plate, and tuft of upward pointing setae below masticatory brush. Aedeagus typical of genus, Penis apodemes fused ( Fig. 2H ). End plate well developed, with a pair of basal sclerites each with a rounded lobe, plus a long projection.

Sequence data. We obtained COI and 28S for this species from two specimens from Florida (UFFE:36821: COI: MZ291629 , 28S: MZ289896 . UFFE:36822: COI: MZ291628 , 28S: MZ289895 ). One specimen from South Africa was also sequenced as part of a different project (Roets et al. unpublished). (COI: MZ291624 , 28S: MZ289899 ). COI had 99.4% identity between samples, 28S was identical. When GenBank and BOLD databases were searched, there were no close matches for COI (all <85% identity). A search of the 28S sequences found that the closest match was Ernoporus corpulentus (Sampson, 1919) (97.4% identity). The specimens from Florida and South Africa did not closely match specimens previously determined as E. parvulus from Thailand (28S: MT122092 , 93.5% identity), corroborated by morphological differences noted below. For all specimens of E. parvulus , the 28S was a low readquality sequence, due to a variable insertion or deletion in the middle of the target region. Consequently, the second half of all sanger reads were partly offset by one base, and not easily discernable, so the 28S sequences are made from only single read coverage over its whole length.

Interspecific variation. The arrangement of the asperities on the pronotal slope is variable, with the first and second row often broken into three or two groups respectively, with some specimens having more aberrant patterns. The antennal club is also sometimes variable, with some specimens possessing incomplete or malformed sutures. The scale-like setae on declivital interstriae 4 and 5 are also variable in shape and proportions, from nearly circular (often in smaller specimens) to more than twice as long as wide, with a somewhat pointed tip (usually in larger specimens). The mature color of specimens collected in flight or arriving at new hosts is also variable, from light brown to almost black.

Taxonomic notes. The first report of this species in the Americas was by Bright & Torres (2006), in which two specimens from Puerto Rico did not match any of the Caribbean fauna, and was described as a new genus and species, Allothenemus minutus . Later, Bright (2019) described an additional species of Ernoporus (as Allothemenus) from a single specimen diagnosed by the slightly larger size, and by the arrangement of the first row of asperities. The distinction between the two putative species is unjustified. The photos of E. minutus by Bright (2019, pages 451 and 461) show all of the diagnostic characters that are given for E. exquisitus . The large series collected in Florida represents a near continuous range of sizes and variable arrangements of the first row of asperities on the pronotal declivity, with the first row as a contiguous row, or broken into two or three groups, and the second row contiguous or in two groups. The alternative diagnostic characters that vary between other Ernoporus spp. are otherwise identical between E. minutus and E. exquisitus .

Ernoporus minor ( Schedl, 1942) is a very similar species, collected from a closely related host plant in Malaysia, Talipariti macrophyllum (Roxb. ex Hornem.) Fryxell. Based on the lectotype (NHMUK) and paralectotype (NHMW), the antennae differ in that the third antennal suture is very close to the top of the antennae, and the gap to the next one is large. The antennae are particularly diagnostic among other Ernoporus species , by the club with a varying number and shape of visible sutures, although it is possible that the specimen is malformed and is of the same species as E. parvulus .

A species of Ernoporus from Thailand was previously identified as E. parvulus ( Johnson et al. 2020 a, Figs. 27C, F, 28E), but clearly differs by the abundant scale-like setae between the strial and interstrial rows on the declivity, and by comparing sequence data. Some other Ernoporus are similar, particularly E. corpulentus , which is much larger (typically greater than 1.4 mm), and males have a much more projected pronotal margin.

Biology. Known from Talipariti tiliaceum . Found on twigs and branches 0.5–2.5 cm, and likely able to breed in larger diameter material. Galleries appear female initiated, joined by a male, and with a transverse gallery ( Fig. 2K ) almost circumscribing the whole twig in smaller material. Larval galleries run longitudinally, or chaotically in thicker bark ( Fig. 2K–L ).

Distribution. Mozambique; South Africa; Dominican Republic; Puerto Rico; Florida.

Economic significance. This species shows no behaviors associated with economic damage. There is no indication of these beetles attacking living plants. Their small size and ability to live in twigs may enable them to be transported though horticulture, especially on ornamental Hibiscus and Talipariti species. There is no evidence that this species can live on native or economically important Malvaceae , such as common hibiscus, Hibiscus syriacus L., cotton, Gossypium hirsutum L., or okra, Abelmoschus esculentus (L.) Moench.

Figures

FIGURE 1. Ernoporus parvulus (Eggers, 1943). A: female, dorsal, lateral, and ventral photographs (UFFE:36956); B: male, dorsal, lateral, and ventral photographs (UFFE:36955).

FIGURE 2. Photographs of E. parvulus morphology. A: frons of female (UFFE:36956), B: frons of male (UFFE:36955), C: declivity of female (UFFE:36956), D: declivity of male (UFFE:36823), E: prolegs of female (UFFE:36956), F: prolegs of male with feather-like setae (UFFE:36956), G: proventriculus (UFFE:36823), H: aedeagus taken from three angles (one of the elongate parts of the basal sclerites is missing) (UFFE:36823). Photographs of host material and galleries, I: Talipariti tiliaceum (L.) Fryxell, with snapped twig in lower right where E. parvulus were collected, J: small twig with abundant, small, circular exit holes, K: pair of E. parvulus in transverse gallery, with longitudinal larval galleries exposed, L: teneral adults under peeled bark.