Sección Morfología, Comportamiento, Ecología y Sistemática

JHON CÉSAR NEITA MORENO¹, BRETT RATCLIFFE², GERMAN CALBERTO^3
1 Maestría en Entomología, Grupo de Sistemática de Insectos-Agronomía. Museo Entomología UNAB. Universidad Nacional de Colombia. Ciudadela
Universitaria Bloque 500, Museo de Entomología 220, Bogotá, Colombia. Autor para correspondencia: Calle 76 bis, No. 94 A 10 Barrio Santa Rosita,
Bogotá, Colombia. cneitaj@unal.edu.co
² Systematics Research Collections, University of Nebraska State Museum, W-436 Nebraska Hall, University of Nebraska, Lincoln, NE 68588-0514, USA, bratcliffe1@unl.edu
³ Asistente de Investigación-Centro Internacional de Agricultura Tropical-CIAT, Laboratorio de Manejo Integrado de Plaga, Recta Cali-Palmira, Palmira, Valle del Cauca, Colombia, gcalberto@yahoo.com

Introduction

The tribe Cyclocephalini contains 14 genera that occur in the New World except for one species of Cyclocephala introduced into Australia and Ruteloryctes morio (Fabricius, 1798), which occurs in western Africa from Guinea to Angola (Endrödi 1985; Jameson et al. 2002). Although species in the tribe Cyclocephalini are well-represented in collections, the larvae have been described for only a few species, and most of those were Nearctic. Accordingly, it is not yet possible to characterize larvae at the tribe level. Larvae of 11 species in three genera in the tribe Cyclocephalini have been previously described (Ritcher 1966; Morelli 1991; Morelli and Alzugaray 1994; Vincini et al. 2000; Ramírez et al. 2004). Our results show that the larvae of Cyclocephalini are distinguished from other American dynastine larvae by the following combination of characters: epipharynx with haptomeral process not entire (but entire in all species of Dyscinetus and in Ancognatha manca LeConte, 1866); plegmatia absent (except wide in Cyclocephala testacea Burmeister, 1847 and narrow in Aspidolea singularis Bates, 1888); dorsal surface of last antennal segment with two sensory spots; ocelli present and often pigmented (all species of Cyclocephala); each tarsal claw with two setae; raster without palidia (with palidia in C. modesta Burmeister, 1847 and C. testacea). The genus Aspidolea Bates contains 25 species that occur from Mexico to Argentina (Endrödi 1985; Ratcliffe 1977, 2003; Martínez 1975; Dechambre 1992). The aims of study were to: 1.) Describe the immature stages of genus Aspidolea (Based on A. singularis Bates, 1888). 2.) Contribute to the knowledge of the larval biology and life cycle of specie A. singularis 3.) provide a key to know third-stage larvae of genera in the tribe Cyclocephalini.

Materials and Methods

Terms and characters used in the description are those of Ritcher (1966), Morón (1987), and Morón and Ratcliffe (1990). Specimens were deposited at the Universidad Nacional de Colombia, Museo Entomológico, Facultad de Agronomía, Bogotá, Colombia (UNAB).

This description is based on four first-instar, three secondinstar, five third-instar, two cast skins of the third-instar larvae and five pupae reared to the adult stage from: COLOMBIA, Cauca, Caldono. 2°47’50”N; 76°29’00”W. 1920 m. In soil of crop (Manihot esculenta Crantz, Euphorbiaceae). 12 Nov 2005. Calvert G. and Neita J. (UNAB).

Head (Fig. 1). Maximum width of head capsule 4.3 mm. Surface of cranium yellowish, finely punctate. Frons. Each side with 2 posterior frontal setae, 1 anterior frontal seta, and 3-2 anterior angle frontal setae; cranial surface with 3 dorsoepicranial setae, 3 epicranial setae, and 7 paraocellar setae on each side. Clypeus with 1 exterior clypeal seta and 2 anterior clypeal setae. Labrum slightly asymmetrical with 2 anterior labral setae, 4 posterior lateral setae on each side, apex with 3 setae, posterior setae absent. Ocelli present, not pigmented. Epipharynx (Fig. 2). Haptomeral process notched forming 2 teeth; heli absent; plegmatia narrow, formed by 14-15 plegmata; right chaetoparia with 67 spine-like setae; left chaetoparia with 55 spine-like setae, without any sensillae; acroparia each with 11 straight, long, thick setae; each acanthoparia with 15 short, curved, spine-like setae; pedium short, ovate. Dexiotorma narrow and elongate; laeotorma slightly shorter than dexiotorma and elongated toward apex, pternotorma rounded. Dexiophoba absent; laeophoba well-developed between haptolachus and inner side of laeotorma, formed by nine slightly slender setae. Sclerotized plate of right nesium long, elongated and truncate at apex; sense cone on left nesium represented by longitudinal, well-sclerotised plate, apex with two sensilla. Crepis not defined. Mandibles. Right mandible (Fig. 3A-C): scissorial area with, blade-like apical tooth (S1 + S2) and 1 rounded tooth (S3) after scissorial notch; scrobe with 6 slender, long setae. Dorsal surface with line of 7 slender, long setae. Ventral surface with elongate-oval stridulatory area formed by 48 narrowly separated ridges; ventral process well-developed, rounded, with many asperites. Brustia with 6 stout, long setae. Calyx large, basolateral setae absent. Molar area with 3 wide, convex, ridged lobes (M1-3) and with 7 slender, long setae. Left mandible (Fig. 4A-C): scissorial area with sinuate, bladelike apical tooth (S1+S2) and 1 rounded tooth (S3) after scissorial notch. Scrobe with 6 slender, long setae. Dorsal surface with line of about 10 slender, moderately long setae; acia welldeveloped, sharp, with 4 setae at apex. Basolateral setae absent. Ventral surface with elongate-oval stridulatory area formed by 46, narrowly separated ridges; ventral process well-developed, rounded, with many asperites; dorsomolar area with row of 6 stout, slender, moderately long setae; brustia with 12 stout, long setae. Molar area with 3 lobes, first molar lobe (M1) large. Maxila (Fig. 5A-B). Cardo subrectangular. Stipes larger than wide. Galea with many stout setae and 1 well-developed uncus at apex. Lacinia with many stout setae and 3 unci (middle uncus shorter than others), base fused. Maxillary palpus 4-segmented, segments 1 and 3 subequal in length, segment 4 slightly longer than segment 2. Stridulatory area with 7 blunt, truncate ridges (Fig. 6) and anterior truncate process. Hypopharynx (Fig. 7). Glossa with 55 slender, long setae and 14 stout, short setae. Hypopharyngeal sclerome asymmetrical, concave medially, sharp process produced dorsally; left lateral lobe with 15 slender, moderately long setae; right lateral lobe with 10 slender, moderaterly long setae. Left margin of sclerome with row of 28 stout, moderately long setae. Antennae. Dorsal surface of last segment with 2 irregularly-shaped, dorsal sensory spots (Fig. 8). Ventral surface of last segment with 2 irregularlyshaped sensory spots (Fig. 9).

Thorax. Prothoracic spiracle (Fig. 10) 0.28 mm long, 0.18 mm wide; respiratory plate yellowish, regularly shaped as a closed “C”, bulla not prominent; distance between respiratory lobes less than diameter of bulla; plate with 21 holes across diameter at middle, holes with irregular edges (Fig. 11). Dorsum of prothorax with transverse row of 9 long, slender setae. Mesoprescutum with transverse, irregular row of 6 long, slender setae; mesoscutellum with transverse row of 4 long, slender setae and 2 stout, spine-like setae. Metaprescutum with 10 long, slender setae and 4 stout, spine-like setae; metaescutellum with 4 long, slender setae and 2 stout, spine-like setae. Legs (Fig. 12A-B): Tarsal claws with enlarged apical process, 1 basoexternal seta, and 1 internal, preapical seta. Tarsal claw on pro-and metathoracic legs shorter than those of mesothoracic legs. Coxa, trochanter, and tibiotarsus of all legs with many fine, stout setae.

Abdomen. Abdominal spiracles I 0.18 mm long and 0.12 mm wide, shorter than spiracles II-VIII. Spiracles on segments II and IV equal in size (0.19 mm long and 0.13 mm wide); spiracles on segments V and VI equal in size (0.19 mm long and 0.19 mm wide); spiracle of segments VII and VIII larger than preceding spiracles (0.2 mm long and 0.22 mm wide). Chaetotaxia on abdominal segments (Table 1).

Raster. Surface without palidia; campus with 8 slender, long setae; teges with 53-55 short setae, barbula with 18 long, slender setae. Anal slit transverse. Approximate dorsal body length 19.5-20.5 mm (Fig. 13).

First-instar. Description based on 6 first-instar larvae taken in soil surrounding cassava crop (Manihot esculenta Crantz. Euphorbiaceae). Similar to second and third-instar larvae, except width of head capsule 1.9-2.3 mm) and body size smaller. Larvae of first and second-instars lack the anterior frontal setae.

Second-instar. Description based on 5 second-instar larvae reared from the first-instar larvae. Similar to third-instar, except width of head capsule 3.5-3.7 mm and body size smaller.

Pupa (Fig. 14A-B).
Description Female (Fig. 14 A-B). Length 15 mm. Widest width 7.5 mm. Head. Surface glabrous, strongly deflexed; antennaa, labrum, mandibles, maxillae and palps discernible; antennal tecae expanded, stout with apex rounded. Thorax. Surface glabrous. Pronotum convex, anterior and posterior angles clearly defined. Meso- and metanotum welldifferentiated. Elytral and posterior wing tecae closely appressed, curved ventrally around body; elytral tecae extending to middle of abdominal segment IV; posterior wing tecae extending to middle of abdominal segment V. Protibia with 3 distinct teeth on external edge. Meso- and metatibiae with inner and external spines well-developed at apex. Abdomen. Segments I-VII (ventral view) well-defined. Segment VII and VIII separated; segments VII and IX fused. Segment X with genital ampulla small (male) and slightly prominent. Segments I-VII (dorsal view) with well-defined, dioneiform organs, the first very sclerotized. Pleural lobes rounded. Spiracle I elongate, with fine peritreme and covered by wing thecae; spiracles II-IV ovate, prominent, with strongly sclerotized peritreme; spiracle V-VIII closed. Abdominal apex rounded, with fine, short setae.

Remarks. The following characters will separate A. singularis from other known Cyclocephalini larvae: Frons with 2 posterior frontal setae, 1 anterior frontal seta, and 2-3 anterior angle frontal setae. Ocelli not pigmented. Epipharynx without sensillae among setae. Tarsal claw on pro- and metathoracic legs shorter than those of mesothoracic legs. Abdominal spiracles I shorter than spiracles II-VIII; spiracles on segments II and IV equal in size; spiracles on segments V and VI equal in size; spiracle of segments VII and VIII larger than preceding spiracles.

Biological data. The adults of both sexes were found in the soil during March and April. Adults are attracted to lights at night, especially from May to June. The larvae are saprophagous and live in soil with organic matter. First-instar larvae were collected in July. From January to February, pupae form weak cells within the soil. This species has a one-year life cycle.

Distribution. Aspidolea singularis is broadly distributed from Mexico to Venezuela, Colombia and Ecuador (Ratcliffe 2003).

Acknowledgments

We thank Dr. Andreas Gaigl for his collaboration during field work. This project was supported, in part, by grants from the Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung (Germany) and International Center for Tropical Agriculture-“Soil Pests” (Colombia) to Jhon César Neita and Germán Calberto. We thank Juan Carlos Pinzón (Entomology Laboratory Assistant) and Edison Torrado (Head of the Laboratory of Entomology, Agronomy College, National University of Colombia). This project was supported by an NSF Biotic Surveys and Inventory grant (DEB 9870202) to B. C. Ratcliffe and R. D. Cave, and a NSF PEET grant (DEB 0118669) to M. L. Jameson and B. C. Ratcliffe.

Literature Cited

DECHAMBRE, R. P. 1992. Nouveaux Cyclocephalini des genres Cyclocephala et Aspidolea (Col. Dynastidae), pp. 57-76. En: Lachaume, G. (eds.). Les Coleopteres du Monde 14 : Dynastidae Américains. Sciences Nat., Venette, France. 87 p., 13 plates.        [ Links ]

ENDRÖDI, S. 1985. The Dynastinae of the World. Dr. W. Junk Publ., Dordrecht. 800 pp., 46 plates.        [ Links ]

JAMESON, M. L.; RATCLIFFE, B. C.; MALY, V. 2002. Review of the genus Acrobolbia Ohaus with remarks on its classification and key to the world genera of Cyclocephalini (Coleoptera: Scarabaeidae: Dynastinae). Folia Heyrovskyana 10: 1-15.        [ Links ]

MARTÍNEZ, A. 1975. Una nueva especie de Aspidolea del Ecuador (Col. Scarabaeidae: Dynastinae). Entomologische Arbeiten aus dem Museum G. Frey 26: 307-313.        [ Links ]

MORELLI, E. 1991. Descripción de la larva y pupa de Cyclocephala signaticollis Burmeister, 1847 (Coleoptera: Scarabaeidae: Dynastinae) y observaciones sobre su biología. Elytron, Supplement 5 (1): 189-195.        [ Links ]

MORELLI, E.; ALZUGARAY, R. 1994. Descripción de la larva de Cyclocephala testacea Burmeister, 1847 y clave para la determinación de larvas de cuatro especies del género Cyclocephala en el Uruguay (Coleoptera: Dynastinae). Revista Brasileira de Biologia 54 (1): 77-84.        [ Links ]

MORÓN, M. A. 1987. Los estados inmaduros de Dynastes hullys Chevrolat (Coleoptera: Melolonthidae: Dynastinae); con observaciones sobre su biología y el crecimiento alométrico del imago. Folia Entomológica Mexicana 73: 33-74.        [ Links ]

MORÓN, M. A.; RATCLIFFE, B. C. 1990. Description of Strategus larvae with a new key to species based on the larvae (Coleoptera: Melolonthidae: Dynastinae). Elytron 4: 53-66.        [ Links ]

RAMÍREZ, C.; MORÓN, M. A.; CASTRO, A. 2004. Descripción de los estados inmaduros de tres especies de Anomala, Ancognatha y Ligyrus (Coleoptera: Melolonthidae: Rutelinae y Dynastinae) con observaciones de su biología. Acta Zoológica Mexicana (n.s) 20 (3): 67-82.        [ Links ]

RATCLIFFE, B. C. 1977. Four new species of Neotropical Cyclocephalini (Coleoptera: Scarabaeidae). Acta Amazónica 7: 429-434.        [ Links ]

RATCLIFFE, B. C. 2003. The dynastine scarab beetles of Costa Rica and Panama (Coleoptera: Scarabaeidae: Dynastinae). Bulletin of the University Nebraska State Museum 16: 1-506.        [ Links ]

RITCHER, P. O. 1966. White grubs and their allies: a study of North American scarabaeoid larvae. Oregon State University Press, Corvallis, OR. 219 p.        [ Links ]

VINCINI, A. M.; LÓPEZ, A. N.; MANETTI, P- L.; ÁLVAREZCASTILLO, H.; CARMIONA, D. M. 2000. Descripción de los estados inmaduros de Dyscinetus rugifrons (Burmeister, 1847) (Coleoptera: Scarabaeidae: Dynastinae). Elytron 14: 91-98.        [ Links ]

Recibido: 22-oct-2006 - Aceptado: 31-oct-2007