Scolytus mundus Wood, 1968

Smith, Sarah M. & Cognato, Anthony I., 2014, A taxonomic monograph of Nearctic Scolytus Geoffroy (Coleoptera, Curculionidae, Scolytinae), ZooKeys 450, pp. 1-182 : 38

Taxon classification Animalia Coleoptera Curculionidae

Scolytus mundus Wood, 1968 Fig. 39

Scolytus mundus Wood, 1968: 13.

Diagnosis.

This species most strongly resembles Scolytus aztecus and Scolytus ventralis . Both sexes are differentiated by elytral apices slightly emarginated only at interstria 3, by ventrite 3 covered with abundant erect setae that are greater than length of segment 3. The male can also be differentiated by the apical margin of ventrite 2 armed with a broad median denticle; larger size, the geographic distribution.

Description (male).

4.0-4.5 mm long (mean = 4.35 mm; n = 4); 2.1-2.5 times as long as wide. Color dark brown to black, antennae red brown. Pronotum same color as elytra.

Head. Epistoma weakly emarginated; epistomal process absent; median area above mandibles bearing dense patch of long, yellow, hair-like setae. Frons appearing convex when viewed laterally, moderately, transversely impressed just above epistoma; strongly, coarsely longitudinally, aciculate-punctate; aciculations converging at epistoma; punctures small, fine; densely, uniformly covered by long, fine, yellow, erect, hair-like setae, setae longer than width of midpoint of eye. Antennal scape short, elongate; club flattened, nearly subquadrate, setose with partial septum, two arcuate sutures visible.

Pronotum as long as wide; apical margin broadly rounded, median area between eyes lined with scales; sides distinctly arcuate, strongly constricted near apex, forming a weak transverse impression near apical margin; surface smooth, shining, punctures on disc fine, shallow, moderately abundant, larger and more abundant laterally and on apical constriction; apical, anterolateral and lateral margins bearing abundant, erect, long, dark yellow-brown, hair-like setae; base weakly bisinuate.

Elytra with sides sub-parallel on apical half, narrowing to subquadrate, smooth apex; elytral apices slightly emarginated at interstria 3; apex weakly emarginated at suture. Margin of apical edge bearing large, coarse punctures. Disc smooth, shining; interstriae weakly impressed, more than twice width of striae, punctures uniseriate, equal in size to those of striae, bearing moderately abundant long, erect, dark yellow-brown, hair-like setae; striae weakly impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of metanepisternum.

Venter. Apical margin of ventrite 1 weakly elevated above base of ventrite 2. Ventrite 2 nearly perpendicular to ventrite 1; surface smooth, shining, finely punctate; punctures small, fine, shallow; covered with abundant erect setae greater than length of segment 3; surface flattened; apical margin armed with broad median denticle; lateral margins of ventrites 2-3 and ventrite 4 unarmed. Ventrite 5 carinate ridge closer to apical margin of segment; length of ventrite 5 greater than combined lengths of ventrites 3 and 4; setal patch and median depression absent.

Female.

3.3-4.6 mm long (mean = 4.0 mm; n = 13); 1.8-2.6 times as long as wide. Similar to male except epistoma feebly emarginated, epistomal process absent, frons convex when viewed laterally, weakly longitudinally aciculate, setae sparser, shorter, less than width of eye; weakly transversely impressed between inner apices of eyes. Apical margin of second ventrite armed by small broad tumescence.

Specimens examined.

28.

Type material.

Holotype: male, labeled "11 mi, N Tlaxco, Puebla, Mexico, SL W[ood], Abies religiosa ." (USNM). Paratypes: MEXICO: [Puebla]: Tlaxco (Tlaxcala), 11 mi N., 8900 ft, 9.VII.1967, S.L. W[ood], ex. Abies religiosa (USNM-21).

Non-type material.

MEXICO: [Distrito Federal]: Desierto de los Leones National Park, III.1951, J.M. Miller, ex. Abies religiosa (OSAC-2). Hidalgo: El Chico, 31.IX.[19]77, E. Hernandez V., ex. Abies religiosa (CNCI-2). Oaxaca: Valle Nacional, 53 mi S., 10000 ft, 24.V.[19]71, D.E. Bright, ex. Abies religiosa (CNCI-2). Tlaxcala: Villarreal Terrenate, 23.II.[19]78, E. Hernandez, ex. Abies religiosa (USNM-4, WFBM-5).

Distribution.

MEXICO: Distrito Federal, Estado de México, Hidalgo, Michoacán, Morelos, Oaxaca, Puebla, Tlaxcala (Fig. 40).

Hosts.

Abies religiosa (Kunth) Schltdl. & Cham. (sacred fir).

Biology.

Scolytus mundus is a serious pest of Abies religiosa in Mexico and its life cycle and habits have been well-studied (see Cibrián Tovar et al. 1995). Scolytus mundus attacks the tops of mature trees, trunks of recently cut trees and large logging slash greater than 10.0 cm in diameter ( Wood 1968; Cibrián Tovar et al. 1995). Trees attacked by Scolytus mundus exhibit red foliage at the tree top. If the population density is high, subsequent generations will colonize the tree from the top down. However, attacks rarely occur at the base and so the host tree typically survives ( Cibrián Tovar et al. 1995). Scolytus mundus has been reported to colonize the same material as Scolytus hermosus ( Wood 1968).

The female initiates the attack by constructing an entrance in bark crevices at branch nodes. The adult galleries are transverse across the grain of the wood, similar in appearance to Scolytus ventralis and with a central nuptial chamber (see Cibrián Tovar et al. 1995, figs 130-131). Eggs are laid in niches excavated on each side of the central nuptial chamber. The larval mines extend parallel to the grain of wood and are first in the cambium and later penetrate into the sapwood. Pupation occurs in the sapwood and there are two generations per year with the first generation occurring from October to May and the second from June to October ( Cibrián Tovar et al. 1995).