OCCURRENCE OF EXTRA AND ANOMALOUS SETAE ON PUPAL ABDOMINAL SEGMENT VIII OF THE DOLOSUS COMPLEX OF CULEX (DIPTERA: CULICIDAE)

Journal of the American Mosquito Control Association, 22(1): 1-4, 2006 Copyright O 2006 by the American Mosquito Control Association, Inc.

OCCURRENCE OF EXTRA AND ANOMALOUS SETAE ON PUPAL ABDOMINAL SEGMENT VIII OF THE DOLOSUS COMPLEX OF CULEX (DIPTERA: CULICIDAE) GUSTAVO C. ROSS1 Centro de Estudios Parasitoldgicos y de Vectores, 2 584-UNLP-CONICET I900 La Plata, Argentina

ABSTRACT. The presence of extra and anomalous setae on abdominal segment VIII of whole and the exuviae of pupae of the Dolosus Complex of Culex is reported. Also, seta 10-VIII in 14 specimens was observed. An anomalous seta 0-VIII is present in a single specimen and was observed to be large and have multiple branches.

KEY WORDS pupa, abdominal segment VIII, setae, anomalous, Culex, Dolosus Complex INTRODUCTION During the re-description of Culex (Culex) dolosus Lynch Arribalzaga, 1891, nearly 100 reared specimens were examined. During the study of larval and adult specimens, a different character became evident that suggested the possibility of more than 1 species. Forattini and Rabello (1956) and Duret and Barreto (1956) commented on the variability of the species, despite specimens having similar male genitalia. Several of these specimens had an anomalous seta on abdominal segment VIII. The most common occurrences of abnormal setae are in the pupal cephalothorax of different genera, i.e., Aedes and Anopheles (Harrison and Peyton 1984; Reinert 1980, 1999), with the presence of seta 13-CT, and in Aedes (Stegomyia) (Tewari and Hiriyan 1990) with seta 14-CT. Other anomalous setae have been described (as seta 0-CT) by Harrison and Peyton (1984) as present on the dorsal apoteme (DAp) of 1 ~ n o ~ h e l pupa. es In the same paper, these authors also described 1 extra seta and the presence of an empty alveolus in the cephalothorax of Anopheles (Cellia) as setae 9a-CT and 9bCT. The seta designated as 1-XI is present in the caudal lobe of 3 species in the Anibalzagia Series of Anopheles and is also present in Toxorhynchites (Harrison and Peyton 1984). The presence of extra and anomalous setae in Culex are reported by Tanaka (2003, 2004a, 2004b). Harbach and Knight (1980) named seta 10-VIII in Belkin's picture of Ae. .futunae.

MATERIALS AND METHODS Ninety-six pupae of reared and mounted specimens of the Dolosus Complex of Culex were studied (Table 1). Larvae of Cx. dolosus s.1. were collected from a semipermanent pond and from another adjacent semipermanent pond at Punta Lara (Ensenada, Buenos Aires Province): 15 L (larvae), 14 P (pupae), 8 F (female), 6 M (male), 20 and 30XI-2000, (A. C. Scorsetti leg.), and 13-XI-2001, 33 L, 22 P, 9 E 9 M, (M. E Achinelli leg.), respec-

tively, and from a regulated stream (Estancia Santa Rosa, Tanti, Cordoba Province, 2-VIII-2002, and 26-X-2002, 20 L, 14 P, 6 E 6 M; G. A. Marti leg.). Other reared specimens of Cx. dolosus s.1. were also sampled in the same semipermanent pond at Punta Lara but on different days (J. J. Garcia and G. C. Rossi leg.). Adults and larvae from distinct localities of Buenos Aires, Corrientes, Entre Rios, and Misiones Provinces (G. C. Rossi leg.) also were revised. All the specimens were reared to adults in the laboratory in pond water. Exuviae from the associated immature stages, 4th-stage larvae, and pupae were collected and mounted in Canada balsam. Adults were pinned. Specimens of the type series of Culex eduardoi Casal and Garcia, a related species that is very difficult to separate from the former, and a larva and 2 male adult paratypes of Cx. bonariensis Brethes, were also included in the examination. The specimens were classified and compared with Lynch Arribalzaga (1891), Brethes (1912, 1916), Dyar (1928), Lane (1951, 1953), Forattini and Rabello (1956), Duret and Barreto (1956), Cova Garcia et al. (1966), Bram (1967), Darsie (1985), and the description of Cx. bilinetaus (Theobald 1903) as a synonym of Cx. dolosus. The specimens were photographed with a phase contrast microscope with a Nikon Optiphot C35 camera and Kodak T400 CN film. All these specimens were deposited in La Plata Museum.

RESULTS The presence of an extra seta on abdominal segment VIII was noted in 14 of the 96 exuviae examined. The seta observed in these specimens corresponded to the position of seta 10-VIII (sensu Harbach and Knight 1980), with a similar degree of development and with the presence of 1 or 2 branches. Because of its position, visualization of this seta is very difficult. It is noticeable at the rear junction of the tergum and sternum (Fig. la). The presence of the seta was noted in 10 male and 4 female pupal exuviae. Of these 14 exuviae, this seta

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Fig. I . (a and b) Details of abdominal segment VIII and posit~onof single setae 10-VII1. ( c ) Details of abdominal segment VIIl double setae 10-VIIl. (d) Details of abdominal segment VlIl with seta 0-VIII triple.

was observed on both sides in 7 exuviae and on I side in the other 7 (Table I). The seta was shorter than 10-VII and simple in 2 of the exuviae. Ten of the pupae had setae with normal development (similar to 10-VII) and single (Figs. la, I b), whereas 4 specimens had seta 10-VIII with 2 branches (Fig. lc). The other anomaly reported here is the presence of a large and multiple branched seta 0-VIII in only I exuvia (2145 from Buenos Aires), with 3 branches of 140 pm length (Fig. Id). All these

anomalous setae were absent in the 3 pupal exuviae of the type series of Cx. eduardoi.

DISCUSSION Harbach and Knight (1980) stated that usually 4 pairs of setae (0, 4, 9, 14-VIII) arise on abdominal segment VIII, with the exception of Aedes (Stg.) futunae Belkin (Belkin 1962), which also has seta 10-VIII. No other comments about extra setae on

Table 1. Variation observed in the occurrence of the extra seta 10-VIII in specimens of Culex dolosus s.1. from Cbrdoba, Buenos Aires Province (2000, 2001, and previous years) and Cx. eduardoi. Locality Cordoba Buenos Aires (2001) Buenos Aires (2000) Buenos Aires (previous) Cx. eduardoi

One side

Both sides

Not visible

4 0 2 1 0

5 0 0 2 0

15 0 34 33 3

abdominal segments of this species are available. Anomalous setae have occurred in species of different genera and have been reported in Aedes (Paraedes) (Reinert 1980), Aedes (Stegomyia) (Belkin 1962, Tewari and Hiriyan 1990), Anopheles (Anopheles) (Harrison and Peyton 1984, Reinert 1999), Anopheles (Nyssorhynchus) (Reinert 1980), Anopheles (Kerteszia) (Zavortink 1973), Bironella (Marks 1976), Culex (Tanaka 2004a, 2004b), Lutzia (Tanaka 2003), Orthopodomyia (Zavortink 1968), Toxorhynchites (Berlin 1969), and Uranotaenia (Peyton 1973). These authors recognized the presence of setae 0-CT, 9a-CT, 9b-CT, 13-CT, 14-CT, 12-VII, 13-V-VIII, and 1-XI. Belkin (1962) showed 2 additional setae, indicated by dashed lines in Fig. 327, for Ae. futunae: 1 is on the metanotum, and corresponds to seta 13-CT, and the other is on abdominal segment VIII and named 10-VIII. However, in the description of the species, these were not mentioned. Harbach and Knight (1980) did mention Belkin's seta but without an illustration. The occurrence of this seta in 14 specimens of Culex, 9 from the same population (Cbrdoba), with the presence of 1 on both sides, confirmed that this is an extra seta and not an anomalous seta. Belkin (1953) stated that the homologies between larval and pupal segments VIII of the abdomen are represented by the pentad hairs, but nevertheless stated that "these homologies are tentative only; I am retaining the arbitrary designation 1-5 for the pentad hairs of segment VIII of the larva." In 1952, Belkin stated: "Serial homologies are implied through the use of the same numbers only within abdominal segments I-VII of the larva and I-VIII of the pupa,. . . Ontogenetic homologies are indicated by the use of the same number in the larva and pupa except between the head, antenna, thorax, segment VIII, and terminal segments of the larva and cephalothorax, segment VIII, terminal abdomen segments, and paddle of the pupa; in these regions, independent terminologies are used for the larval and pupa" (Belkin 1952). Finally, the distinct seta 0-VIII, from another unique exuviae, with 3 branches and 140 p,m long, is also the 1st report of such an anomaly for this seta.

ACKNOWLEDGMENT I thank J. E Reinert (Center for Medical, Agricultural, and Veterinary Entomology) for reviewing the manuscript. REFERENCES CITED Belkin JN. 1952. The homology of the chaetotaxy of immature mosquitoes and revised nomenclature for the chaetotaxy of the pupa (Diptera: Culicidae). Proc Entom01 Soc Wash 54:115-130. Belkin JN. 1953. Corrected interpretations of some elements of the abdominal chaetotaxy of the mosquito larva and pupa. Proc Entomol Soc Wash 55:318-324. Belkin JN. 1962. The mosquitoes of the South Pacijic (Diptera, Culicidae) Berkeley, CA: Univ. of California Press. Berlin OGW. 1969. Mosquito studies (Diptera, Culicidae) XIV. Redescription of Toxorhynchites (T.) gigantulus from the Philippines. Contrib Am Entomol Inst 4:21-26. Bram RA. 1967. Classification of Culex subgenus Cu1e.x in the New World (Diptera: Culicidae). Proc U S Nut Mus 12O:l-122. Brethes J. 1912. Los mosquitos de la Repliblica Argentina. Bol Ins Entomol Patol Veg 1:l-48. Brethes J. 1916. Algunas notas sobre mosquitos argentinos. An Mus Nac Hist Nut Bs As 28:193-218. Casal OH, Garcia M. 1968. Culex (Culex) eduardoi, una nueva especie de la Repdblica Argentina (Diptera, Culicidae). Rev Soc Entomol Argent 30: 105-1 11. Cova Garcia P, Sutil y E, Rausseo JA. 1966. Mosquitos (Culicinos) de Venezuela Volumes 1 and 2. Caracas: Ed Minist de Saneam y Asist Soc. Darsie RE 1985. The mosquitoes of Argentina. Mosq Syst 17: 153-360. Duret JP, Barreto EMF? 1956. Notas sobre Culicidas do estado de Sao Paulo, Brasil corn descricoes de tres novas especies de Culex (Diptera: Culicidae). Rev Brazil Entomol 5:8 1-99, Dyar HG. 1928. The mosquitoes of the Americas Washington, DC: Carnegie Institute. Forattini OP, Rabello EX. 1956. Notas sobre Culicidae (Diptera). 6. Novos dados sobre algumas especies do subgenero Culex. Papeis Avulsos 17:27-34. Harbach RE, Knight KL. 1980. Taxonomist's glossary of mosquito anatomy Marlton, NJ: Plexus Publishing. Harrison BA, Peyton EL. 1984. The value of the pupal stage to Anopheline taxonomy, with notes on anomalous setae (Diptera: Culicidae). Mosq Syst 16:201-210. Lane J. 1951. Synonymy of Neotropical Culicidae (Diptera). Proc Entomol Soc Wash 53:333-336. Lane 1. 1953. Neotropical Culicidae Volumes 1 and 2. Sao Paulo, Brazil: Univ. Sao Paulo. Lynch Arrizabdlza E 1891. Dipterologia Argentina. Rev Mus La Plata 2:133-170. Marks EN. 1976. Occurrence of a fourth metanotal seta on the pupa of Bironella confisa Bonne-Wepster. Mosq Sysr 8:llO. Peyton E. 1973. Notes on the genus Uranotaenia. Mosq Sysr 5:194-196. Reinert JE 1980. A literature review of pupal seta 13-CT in the family Culicidae (Diptera) and report of its occurrence in Aedes aictotaeniatus Edwards. Mosq Syst 12:441-444. Reinert JE 1999. Morphological abnormalities in species of the Quadrimaculatus Complex of Anopheles (Diptera: Culicidae). J Am Mosq Control Assoc 15:8-14.

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