Micrapate spinula Liu, 2024

Liu, Lan-Yu, Beaver, Roger A. & Flechtmann, Carlos A. H., 2024, A new species of Micrapate (Insecta: Coleoptera: Bostrichidae) from Brazil, with a key to Brazilian species, Zootaxa 5433 (2), pp. 266-276 : 269-274

Micrapate spinula Liu , sp. nov.

Figs. 1A–E

Type material

Holotype

BRAZIL: ♂, [MS (state of Mato Grosso do Sul)- Selvíria, UNESP Farm , 20°20'17.52"S 51°24'42.92"W, cerradão fragment in advanced stage of regeneration], 6-m ethanol-baited FIT height, 29/VIII/2014, Leonel, F.L.L. col. ( MEFEIS).

Allotype

BRAZIL: ♀, (MEFEIS), same data as for the holotype.

Paratypes

BRAZIL: 1♂ (LYL) as previous but: 20°20'12.95"S 51°24'45.06"W, unbaited window trap, 13/VII/2011, Silva, J.C.C. col.; 1♂ (LYL) as previous but: cerradão fragment in advanced stage of regeneration, 20°22'56.3"S 51°24'45.1"W, ethanol-baited window trap, 19/VIII/2017, Paiola, G. col.; 1♀ (LYL) as previous but: 20°20'12.95"S 51°24'45.06"W, ethanol-baited FIT, 18/VIII/2011, Silva, J.C.C. col.; 1♀ (LYL) same data as for the holotype but: 8-m ethanol-baited FIT, 07/VI/2014, Leonel, F.L.L. col.. 1♂, 1♀ (RBINS), as previous but: 20°20'12.95"S 51°24'45.06"W, ethanol-baited FIT, 11/VIII/2011, Silva, J.C.C. col.. 1♂ (MEFEIS) MINAS GERAIS: São Roque de Minas, Fazenda Taquaril, Khaya grandifoliola stand planted in February 2013, 20°7'05.63"S 46°27'05.98"W, 96% ethanol-baited FIT, 28-IX-2018, L.S Covre; 1♀ (MEFEIS) same as previous but Khaya grandifoliola stand planted in January 2013, 20°7'44.98"S 46°27'05.10"W, 13-VII-2018; 1♂ (MEFEIS) Natalândia, Fazenda Mamoneira, Khaya senegalensis planted November 2019, 16°30'59.00"S 46°31'8.06"W, 96% ethanol-baited FIT, 05-VII-2022; 1♀ (MEFEIS) Capinópolis, Fazenda Grama, Khaya grandifoliola stand planted in November 2015, 18°46'07.3"S 49°28'38.6"W, 96% ethanol-baited FIT, 24-VIII-2023, C. Faria.

Differential diagnosis

In the Neotropical fauna, the new species is similar to M. bicostula , M. cribripennis and M. germaini in the rather coarse surface of the elytra including the declivity, the elytra obliquely angled to the apex in the last fifth, and the large punctures of the declivity. The uniform black color of the fully pigmented adult, and large pointed spines on the lower half of the raised suture of the elytral declivity easily distinguish M. spinula sp. nov. from the other three similar species.

Description

Male:

Body: 2.5–3.3 mm long, 2.7–3.2 times as long as wide (n=6).

Overall color black, with antennae, clypeus, labrum, maxillary palpi, sides of fourth visible abdominal ventrite and last ventrite, tibiae and tarsi reddish brown.

Head. Frons simple with sparse punctures in the median circle, and confluent punctures outside the median circle, each puncture with a short, white hair directed toward middle. Clypeus finely punctured, with long, golden hairs; anterior margin granulate, deeply concave. Fronto-clypeal suture distinct, shining. Mandibles short, stout, crossed at tips. Antennae 10-segmented, segments 3–7 together slightly longer than first segment of club; first and second segments of club sub-triangular, slightly wider than long, last segment sub-oval, and longer than penultimate segment; club segments matt with short, erect, golden hairs on the apical half of each segment. Eyes normal, posteriorly slightly detached from cheeks.

Pronotum 0.9–1.1 times wider than long, parallel-sided, shining, sides slightly convergent in anterior onethird, anterior margin slightly concave, semicircular area behind margin granulate; antero-lateral area with a series of 3–4 large, recurved teeth on each side; smaller recurved teeth between the larger teeth and on the anterior slope, becoming smaller toward summit and arranged in semi-circular lines; posterior part shining, sparsely punctured, punctures in middle larger, each puncture with a short, white recumbent hair directed anteriorly; a distinct, narrow, glabrous middle line from base to summit; posterior angles granulate.

Scutellum transverse, tongue-shaped, with sparse punctures.

Elytra 1.75–2.2 times longer than wide (n=6), parallel-sided in basal 5/6, then obliquely angled to apex; shining on disc, matt on sides; disc with moderately strong punctures, bearing minute hairs, largest punctures next to suture, smaller and shallower towards sides, punctures become deeper and larger posteriorly, interspaces between the larger punctures granulate; declivity concave along suture on each side of strongly raised suture, declivital punctures large, deep, honeycomb-like, interspaces between punctures granulate; vestiture of sparse, short, recumbent golden hairs; suture raised, more strongly from middle to apex of declivity, with a series of pointed tubercles on outer side of raised area, central tubercle of series largest, others gradually smaller towards the upper and lower margins; posterior margin of elytra with a series of small, blunt teeth beneath.

Abdomen. Ventral side shining, evenly, moderately punctured, punctures with short, white hairs; first to fourth visible ventrites simple, transverse and almost equal in length with paler posterior margin fringed with white hairs; last ventrite evenly transversely rounded, finely punctured, with long reddish-yellow pubescence directed ventrally.

Legs. Procoxal cavities continuous; outer face of protibia flat, fringed with golden hairs on both sides; inferoposterior angle of tibiae with a long, straight spine.

Female: Generally similar to male including the length, width, and body proportions (n=12), but middle of summit of pronotum glabrous, disc shining, without median line, or line indistinct. Elytral declivity more strongly concave on either side of suture, suture more strongly raised, and spine-like tubercles on suture larger; last visible abdominal ventrite slightly convex in middle close to posterior margin, with long, golden hairs converging in middle to form a triangular tuft of hairs.

Etymology

The name “spinula ” is from the Latin word for thorn or spine, and refers to the remarkable series of pointed tubercles on the middle part of the suture of the elytral declivity.

Distribution

Brazil (Mato Grosso do Sul, Minas Gerais) ( Fig. 4 ).

Biology

Most specimens of M. spinula were collected from window or flight intercept traps baited with ethanol. However, the species was also collected from the woody liana, Serjania lethalis A.St. -Hil. ( Sapindaceae ), commonly known in Brazil as timbó, which is widely distributed in Brazil, including in the dry cerrado biome ( Sommer 2009). It is known for its abundant array of allelochemicals ( Rodríguez & Pinto 2014) with phytotoxic and insecticidal properties ( Andrade et al. 2015), including serjonoids (saponins), which are notable for their toxicity to fish ( Teixeira et al. 1984).

Beetles were found actively boring in dead and dying parts of the liana, 7‒25 mm diameter, during the dry season in Selvíria from August to November 2020. All stages of the life cycle were present at one time, suggesting overlapping generations. The beetle begins its gallery by creating a short gallery perpendicular to the liana's trunk axis. Subsequently, the beetle bores either upward or downward along this axis, typically within the pith of the stem. Galleries containing adults were 5‒22 mm long and packed with frass. Galleries were separate when beetle densities were low but overlapped at high-densities.

From one to five adults occurred in a single gallery. If two adults were present, they were a male-female pair. The presence of five adults is likely to be a consequence of high beetle density, leading to gallery overlapping. The sex ratio of adults was close to 1:1 (24 ♂♂: 27 ♀♀).

Eggs were not found, despite extensive searching. Larval galleries (5‒30 mm long) ran parallel to the longitudinal axis of the host stem, occasionally curving towards the bark at their end. Normally a single larva occupied each gallery, but in one case, two larvae were present, one situated at each end of the gallery, facing towards the end. Pupae were consistently found at the end of the larval galleries ( Fig. 5 ). As is usual in small bostrichids ( Liu et al. 2008; LYL per obs.), no distinct pupal chamber was formed, the pupa lying freely in the gallery.

Natural Enemies

Within the beetle galleries, we encountered pupae (which later emerged as adults) and one adult of hymenopteran parasitoids. These were determined as two species of Ecphylus Foerster ( Hymenoptera : Braconidae ). Only a few Ecphylus species are known from the Neotropical Region ( Matthews 1969; Marsh 2002), and none has been recorded in Brazil. A few Ecphylus species have been reported to parasitize Bostrichidae ( Marsh 1979) , although most attack bark beetles ( Curculionidae : Scolytinae ) ( Belokobylskij 2009). Voucher specimens are deposited in the Invertebrate Collection of the Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, state of Amazonas, Brazil.

Figures

FIGURE 1. Micrapate spinula sp. nov. (A) Dorsal view. (B) Ventral view. (C) Lateral view. (D) Front view. (E) Elytral declivity.

FIGURE 4. Distribution of Micrapate spinula sp. nov. in Brazil, showing the location of the cerrado (savanna-like) biome. MS—state of Mato Grosso do Sul, MG—state of Minas Gerais. (Map resource: http://terrabrasilis.dpi.inpe.br)

FIGURE 5. Pupa (above) and teneral adult (below) of Micrapate spinula sp. nov. in galleries bored in the pith of Serjania lethalis, Selvíria, state of Mato Grosso do Sul, Brazil.