Embates sinuatus (Champion)

Prena, Jens, 2005, The Middle American species of Embates Chevrolat (Coleoptera: Curculionidae: Baridinae), Zootaxa 1100 (1), pp. 1-151 : 1-151

19. Embates sinuatus (Champion)

( Fig. 25 , 80–85, 250)

Ambates sinuatus Champion 1907: 159 . Lectotype female, Panama, here designated, labeled: “sp. figured”, “Type”, “ ♀ ”, “Bugaba/ Panama / Champion” (BMNH). Paralectotypes 3, here designated: Bugaba (BMNH), Volcán (BMNH 2). O’Brien & Wibmer 1982 (cat.); Hustache 1938 (cat.)

Ambates sp. 5 . Marquis 1991: 200

Embates [ sinuatus ]. Alonso­Zarazaga & Lyal 1999 (global combination of all species of Ambates Schönherr 1836 with Embates Chevrolat 1833 )

Redescription. Habitus: Fig. 80–81, total length 4.7–7.3 mm (m=5.9, n=217). Color: integument piceous, legs and antenna variously rufous; scales ochreous and black, pronotum with broad dorsolateral vitta of ochreous scales (occasionally with thin dorsomedian vitta), elytral vestiture variable: ochreous scales condensed in compound dorsolateral vitta formed by post­macular, ante­macular and humeral elements (Fig. 80), same scales with various densities in inner elytral interstriae and dorsomedian portion of pronotum; scales black in elytral macula and on preapical callus; venter with yellow scales except medially, frequently condensed on metasternum. Head: frontal fovea absent, rostrum moderately stout, subcylindrical, with sides slightly attenuated between apex and antennal insertion, curved (Fig. 82), costate dorsomedially, basolateral margin produced, length of rostrum ♂♂ 0.95–1.25 x (m=1.10, n=128), ♀♀ 1.03–1.33 x (m=1.20, n=89) pronotal length, length of ante­antennal portion ♂♂ 0.30–0.39 x (m=0.34, n=128), ♀♀ 0.36–0.42 x (m=0.38, n=89) total rostral length, dorsal margin of antennal scrobe reaching rostral base before eye; length of funicular segments 1 and 2 subequal, club oblong ovate. Pronotum: length 0.88–1.03 x (m=0.96, n=217) maximum width, sides rounded, widest in basal half, anterior portion tubulate; punctation dense and confluent, intervals granulose. Elytra: length 1.77–2.04 x (m=1.88, n=216) width at humeri, width 1.15–1.42 x (m=1.27, n=216) maximum pronotal width, sides subparallel in basal half, then increasingly narrowed toward apex, apices rounded conjointly, preapical callus moderate, striae fine, punctures indistinct, interstriae flat, 9 subcostate. Legs: tibiae nearly straight, ventrodistally with fringe (♂♂) or cluster (♀♀) of yellow hairs, protibial mucro notably produced (Fig. 83), tarsal claws arcuate and separate at base. Male: apex of aedeagus blunt or indistinctly notched, anterolateral portion membranous (Fig. 84), body of aedeagus of moderate length, basal third angular in lateral view, apodemes 2.0 x longer than body of aedeagus, flagellum very thin, as long as apodemes, transition to curved base gradual, basal appendage slender, imperfectly fused subdistally with base of flagellum, projecting beyond base (Fig. 85).

Plant association. Piper augustum (Marquis 2, Prena 51): La Selva, P.N. Braulio Carrillo, San Ramon, P.N. Tapantí, M.N. Guayabo, Península de Osa, Cerro Chucuyo, Dúrika, San Vito, Chriqui Grande, La Fortuna; P. arieianum (Marquis 10, Prena 27): Bartola, La Selva, P.N. Braulio Carrillo; P. biseriatum (Marquis 2): La Selva; P. phytolaccaefolium (Prena 7): Península de Osa, Las Mellizas; P. riparense (Marquis 1): La Selva.

Distribution. Atlantic side of Honduras southward (probably entire Mosquito coast) to central Panama (Fig. 250).

Material examined. HONDURAS. Gracias a Dios: Río Plátano , 30 km S Las Marías, 150 m ( JPPC 3 , RDCC) . NICARAGUA. Río San Juan: 7 km SE El Castillo, Refugio Bartola , 30 m ( JPPC, SEAN) . COSTA RICA. Alajuela: Est. San Ramon, 620 m ( INBC) ; Río San Lorencito , 5 km N Colonia Palmarena, 900 m ( INBC, JPPC 9 ) . Cartago: 7 km N Turrialba , M.N. Guayabo, 1100 m ( JPPC 2 ) ; Turrialba , 700 m ( CWOB) ; Tucurrique , 770 m ( NMNH) ; P.N. Tapantí, Quebrada Segunda, 1300 m ( JPPC 7 ) . Guanacaste: Tierras Morenas, Río San Lorenzo , 1050 m ( INBC 4 ) ; 9 km S Santa Cecilia, Est. Pitilla , 700 m ( INBC 3 ) . Heredia: 3 km S Puerto Viejo, Est. La Selva ( CHAH 2 , CMNC, CWOB 2 , INBC 2 , JPPC 31 , NMNH 23 ) ; P.N. Braulio Carrillo , 200 m ( INBC 3 ), 300 m ( INBC 8 , JPPC 9 ), 500 m ( CNCI, INBC 4 , JPPC 19 ), 600 m ( INBC 4 , JPPC 11 ), 700 m ( JPPC 8 ), 1070 m ( INBC 4 , JPPC 5 ), 1500 m ( INBC) . Limón: P.N. Tortuguero ( INBC 3 ) ; 30 km N Cariari ( INBC 3 , JPPC) ; Finca Hamburgo , 50 m ( NMNH) . Puntarenas: P.N. Corcovado, Est. Agujas, 300 m ( JPPC 4 ) , Cerro Rincón , 700 m ( JPPC) , Los Chiles ( INBC) , Los Patos ( JPPC 2 ) ; 24 km W Piedras Blancas ( CWOB) ; Fila Cruces , 1200–1400 m ( INBC 4 ) ; 4 km S San Vito ( INBC, JPPC 5 , SNSD) ; P.N. Amistad, Mellizas, 1400 m ( JPPC) ; Altamira , 1400 m ( INBC), 1900 m ( JPPC 5 ) ; Fundación Dúrika , 1700 m ( JPPC 2 ) ; Est. Pittier , 1600 m ( INBC 2 ) ; Monteverde , 1500 m ( CMNC, CWOB) . San José: 12 km NE San Isidro, Cerro Chucuyo , 1350 m ( JPPC 10 ) . PANAMA. Bocas del Toro: Corriente Grande ( HPSC 3 ) ; 4 km W Chiriquí Grande, 50 m ( JPPC 3 ) . Chiriquí: Volcán ( BMNH 2 ) ; Bugaba ( BMNH 2 ) ; Reserva La Fortuna , 1100 m ( CNIC, CWOB 2 , FAUP, JPPC 10 ) ; 6 km N Boquete , 1450 m ( CMNC) . Coclé: La Mesa above El Valle, 850 m ( HPSC) . Panamá: Cerro Campana , 850 m ( BMNH, CHAH, CWOB, HPSC, TAMU) . San Blás: Nusagandi , 200 m ( CWOB) . Veraguas: Cerro Tute, Santa Fe, 680 m ( FAUP) . Total 256 specimens .

Discussion. Embates sinuatus and E. tetrastigma form a morphological complex that is defined by the possession of a strongly developed protibial mucro in the males (Fig. 83). The classification of the various subpopulations is not without problems. Embates sinuatus is a common species in the evergreen forests between eastern Honduras and central Panama. A preliminary survey in the initial phase of the study revealed a frustrating degree of heterogeneity, and subsequent field work was designated to explore its nature. It turned out, that E. tetrastigma is monophagous on Piper nudifolium and that its occurrence is restricted to the Pacific side of the Cordillera de Talamanca, where it co­occurs with E. sinuatus . The aedeagus of E. tetrastigma is larger (relative to body size) and notched apically, and the flagellum is longer than in E. sinuatus . This is sufficient evidence to consider E. tetrastigma a distinct species. Embates sinuatus feeds primarily on Piper augustum and, alternatively, on P. phytolaccaefolium on the Pacific side, and P. arieianum on the Atlantic side of the Cordilleras, respectively. The various local populations of E. sinuatus exhibit notable variability in their color­patterns and body shapes. Statistical analyses demonstrated a significant effect of elevation on body shape (p<0.001, r²=0.48, n=215). Fig. 25 illustrates this relationship for four subsets of data, and the effect can be demonstrated even for the merely 30 km long ALAS transect in Braulio Carrillo National Park, Costa Rica. In other words, specimens from high elevations are on average more slender than specimens from the lowlands of both sides of the Cordilleras. The variability in the body proportion is accompanied by modifications of the color­pattern. It is important to take into account the compound nature of the elytral vitta, which consists of post­macular, antemacular and humeral elements. Each single element may vary in length, width, position, bearing and size of scales, thereby affecting the size and the shape of the dark elytral macula. Thus modified, the latter comes in a variety of shapes ranging from rhomboid, triangu­ lar to oval, and frequently is affected additionally by the variously dense vestiture on the inner elytral interstriae. As morphological variability can be explained at least partially by environmental variables, and the distinction of local color varieties seems without practical value, I lump the material together under the name E. sinuatus , but maintain E. tetrastigma as a distinct species.

Figures

FIGURE 25. Relationship between elevation of collecting site and metric proportion of elytron in local populations of E. sinuatus (r²= 0.48, p<0.001, n=215)