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Immature stages of Aspidolea singularis (Coleoptera: Scarabaeidae: Cyclocephalini).

Estados inmaduros de Aspidolea singularis (Coleoptera: Scarabaeidae: Cyclocephalini).

Abstract: The larva and pupa of Aspidolea singularis (Scarabaeidae: Dynastinae: Cyclocephalini) are described for first time based on specimens from Colombia. A key to the known third instar larvae of genera in the tribe Cyclocephalini is included. Data on the larval biology of Aspidolea singularis are provided.

Key words: Dynastinae. Larvae. Pupa. Key. Biology.

Resumen: Se describen por primera vez la larva y la pupa de Aspidolea singularis (Scarabaeidae: Dynastinae: Cyclocephalini) con base en especimenes procedentes de Colombia. Se incluye una clave para las larvas de tercer instar conocidas de los generos de la tribu Cyclocephalini. Se proveen datos de la biologia larval de la especie Aspidolea singularis.

Palabras clave: Dynastinae. Larvas. Pupa. Clave. Biologia.

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 (Endrodi 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; Ramirez 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 (Endrodi 1985; Ratcliffe 1977, 2003; Martinez 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), Moron (1987), and Moron and Ratcliffe (1990). Specimens were deposited at the Universidad Nacional de Colombia, Museo Entomologico, Facultad de Agronomia, Bogota, Colombia (UNAB).

Results Aspidolea singularis Bates, 1888. (Figs. 1-14) Third-Instar

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[grados]47'50"N; 76[grados]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 ([S.sub.1] + [S.sub.2]) and 1 rounded tooth ([S.sub.3]) 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 ([M.sub.1-3]) and with 7 slender, long setae. Left mandible (Fig. 4A-C): scissorial area with sinuate, bladelike apieal tooth ([S.sub.1] + [S.sub.2]) and 1 rounded tooth ([S.sub.3]) 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 ([M.sub.1]) 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, coneave 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).

[FIGURA 1 OMITIR]

[FIGURA 2 OMITIR]

Thorax. Prothoraeic 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.

[FIGURA 3 OMITIR]

[FIGURA 4 OMITIR]

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 o 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 selerotized 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; spiraeles 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.

[FIGURA 5 OMITIR

[FIGURA 6 OMITIR

[FIGURA 7 OMITIR

[FIGURA 8 OMITIR

[FIGURA 9 OMITIR

[FIGURA 10 OMITIR

[FIGURA 11 OMITIR

[FIGURA 12 OMITIR

[FIGURA 13 OMITIR

[FIGURA 14 OMITIR

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

Key to the Known Third-instar Larvae of Cyclocephalini

(Modified from Ritcher 1966)

1. Left mandible lacking 4th scissorial tooth 3

1'. Left mandible with 4 scissorial teeth 2

2. Cranium with posterior frontal seta present. Haptomeral process of epipharynx prominent and entire Dyscinetus Harold

2'. Cranium with posterior frontal seta absent. Haptomeral process of epipharynx notched, forming 2 teeth (entire in Ancognatha manca LeConte) Ancognatha Erichson

3. Ocelli not pigmented. Epipharynx without sensillae among setae Aspidolea Bates

3'. Ocelli pigmented. Epipharynx with many sensillae among setae Cyclocephala Dejean

Acknowledgments

We thank Dr. Andreas Gaigl for his collaboration during field work. This project was supported, in part, by grants from the Bundesministerium fur wirtschaftliche Zusammenarbeit und Entwicklung (Germany) and International Center for Tropical Agriculture-"Soil Pests" (Colombia) to Jhon Cesar Neita and German Calberto. We thank Juan Carlos Pinzon (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, (3. (eds.). Les Coleopteres du Monde 14 : Dynastidae Americains. Sciences Nat., Venette, France. 87 p., 13 plates.

ENDRODI, S. 1985. The Dynastinae of the World. Dr. W. Junk Publ., Dordrecht. 800 pp., 46 plates.

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.

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

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

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

MORON, M. A. 1987. Los estados inmaduros de Dynastes hullys Chevrolat (Coleoptera: Melolonthidae: Dynastinae); con observaciones sobre su biologia y el crecimiento alometrico del imago. Folia Entomologica Mexicana 73: 33-74.

MORON, 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.

RAMIREZ, C.; MORON, M. A.; CASTRO, A. 2004. Descripcion de los estados inmaduros de tres especies de Anomala, Ancognatha y Ligyrus (Coleoptera: Melolonthidae: Rutelinae y Dynastinae) con observaciones de su biologia. Acta Zoologica Mexicana (n.s) 20 (3): 67-82. RATCLIFFE, B. C. 1977. Four new species of Neotropical Cyclocephalini (Coleoptera: Scarabaeidae). Acta Amazonica 7: 429-434.

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.

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

VINCINI, A. M.; LOPEZ, A. N.; MANETTI, P- L.; ALVAREZ-CASTILLO, H.; CARMIONA, D. M. 2000. Descripcion de los estados inmaduros de Dyscinetus rugifrons (Burmeister, 1847) (Coleoptera: Scarabaeidae: Dynastinae). Elytron 14: 91-98.

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

(1) Maestria en Entomologia, Grupo de Sistematica de Insectos-Agronomia. Museo Entomologia UNAB. Universidad Nacional de Colombia. Ciudadela Universitaria Bloque 500, Museo de Entomologia 220, Bogota, Colombia. Autor para correspondencia: Calle 76 bis, No. 94 A 10 Barrio Santa Rosita, Bogota, 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 Investigacion-Centro Internacional de Agricultura Tropical-CIAT, Laboratorio de Manejo Integrado de Plaga, Recta Cali-Palmira, Palmira, Valle del Cauca, Colombia, gcalberto@yahoo.com
Table 1. Chaetotaxia on abdominal segments.

Organ                                  Long,            Short,
                                   siender setae   spine-like setae

Abdominal segment I
  Prescutum                              4                 2
  Subscutum                           Absent            Absent
  Scutum                                 8                16
  Scutellum                             10                10
Abdominal segment II
  Prescutum                              4                16
  Subscutum                              1                 3
  Scutum                                10                35
  Scutellum                              7                28
Abdominal segment III
  Prescutum                              4                22
  Subscutum                              1                 3
  Scutum                                 8                44
  Scutellum                              8                31
Abdominal segment IV
  Prescutum                             24                 4
  Subscutum                              1                 3
  Scutum                                 8                39
  Scutellum                             10                33
Abdominal segment V
  Prescutum                              4                25
  Subscutum                              1                 3
  Scutum                                19                40
  Scutellum                             10                34
Abdominal segment VI
  Prescutum                              4                33
  Subscutum                              1                 3
  Scutum                                19                28
  Scutellum                             10                15
Abdominal segment VII
  (2 row).                               8                13
  Abdominal segment VIII (2 row)      10-13             Absent
  Abdominal segment IX (2 row)          10              Absent

* Note: Abdominal segment X with approximately 80 moderate to long,
slender setae.

All spiracular areas with 3 long, slender setae and 1 short, spine-like
seta.

Pleural lobes with 5 long, slender setae and 2 stout, short setae.
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Author:Neita Moreno, Jhon Cesar; RatCliffe, Brett; Calberto, German
Publication:Revista Colombiana de Entomologia
Date:Jul 1, 2007
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