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Trichomycetes living in the guts of aquatic insects of Misiones and Tierra del Fuego, Argentina

     CEPAVE (Centro de Estudios Parasitológicos y de Vectores) (CONICET-UNLP), 2 No. 584, (1900) La Plata, Argentina

Sixto Coscarón

     Museo de Ciencias Naturales, Paseo del Bosque s/n (1900) La Plata, Argentina

	ABSTRACT

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Fourteen species of Trichomycetes living in the guts of aquatic insects are reported from two provinces of Argentina, Misiones and Tierra del Fuego. Twelve of the species belong to the Harpellales and two are Amoebidiales. Five harpellid species are reported from Misiones in the extreme northeast of the country (Genistellospora homothallica, Harpella tica, Smittium culisetae, Smittium sp., Stachylina sp.) and seven are from Tierra del Fuego, the southern tip of South America (H. meridianalis, Glotzia sp., S. culicis, S. cellaspora, S. imitatum, Stachylina minima, Penella simulii). Insect hosts all were immature stages of Culicidae, Simuliidae, Chironomidae, Ceratopogonidae (Insecta: Diptera), and Ephemeroptera and Plecoptera. The lower diversity of Trichomycetes found at Misiones, which has a subtropical climate and rainforest vegetation, was due possibly to the warmer temperatures of the water (15–24 C), compared to the colder streams of Tierra del Fuego (9–15 C), with forests and steppes as typical vegetation.

Key words: biogeography, Chironomidae, Culicidae, Ephemeroptera, fungi, Harpellales, insects, Simuliidae

	INTRODUCTION

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Trichomycetes live obligately in the guts of arthropods and are found all over the world, mostly in Insecta but also in Crustacea and Diplopoda. They live generally as commensalistic symbionts, although some are reported to be pathogens and also may cause parasitic castration of adult females in some insect groups (Labeyrie et al 1996, Yeboah et al 1984).

Surveys of Trichomycetes in Argentina have been conducted in Patagonia and the pampeana region (López Lastra 1997, Lichtwardt et al 1999, Cafaro 2000), as well as in the northwestern provinces (Lichtwardt et al 2000), resulting not only in the discovery of new sites but also three new species and seven new records for Argentina. Other studies have focused on prevalence and seasonality of Trichomycetes from aquatic insects in Argentina (Campos et al 1995, García et al 1994, 1995; Maciá et al 1995, 1997; López Lastra et al 2003).

The present study concerns Trichomycetes living in the guts of aquatic insects from two previously unexplored biogeographic regions of Argentina-Mi-siones in the northeast and Tierra del Fuego at the southern tip of South America. We report the occurrence of 14 new Trichomycete species from infected insect hosts in Argentina, and some of the fungal species are new records for South America. Six of the fungal species were identified from immature aquatic insects. Of 26 sites sampled in Misiones, Trichomycetes were recorded from 10; the insect hosts were different at each site and included members of the Diptera (Culicidae, Chironomidae, Ceratopogonidae and Simuliidae) and Ephemeroptera. Eight species of Trichomycetes were found in 22 aquatic habitats at 12 sites in Tierra del Fuego; the hosts included larval Diptera (Chironomidae, Culicidae, Simuliidae) and nymphs of Ephemeroptera and Plecoptera.

	MATERIALS AND METHODS

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The areas sampled covered much of each province’s territory (FIG. 1). A list of the sites where Trichomycetes were found is presented (TABLE I). Larvae were collected from different aquatic environments, including streams and rivers, by removing insects from stones or other aquatic substrata. In ponds and other lentic habitats we used food strainers or aquatic sampling nets. Lotic insects were kept on ice and transported to the laboratory for dissecting. Fungal specimens in distilled water mounts were examined under a microscope (Olympus CH 30) equipped with phase contrast, and photographs were taken with an Olympus camera (SC 35) adapted to the microscope. Microscopic slide preparations were preserved by infiltrating lactophenol-cotton blue under the cover slip, then sealing with clear fingernail polish. Dissected and intact host specimens were preserved in 70% ethanol for later identification. Axenic isolates were attempted using gut-removed thalli, first rinsed with antibiotic then placed in diluted Brain-heart-infusion agar medium (1/10 BHIA) overlaid with sterile distilled water and antibiotics (Lichtwardt 1986), but none of the cultures survived over time. Selected fungi were preserved in 2 x CTAB DNA extraction buffer for later molecular studies.

View larger version (31K): [in this window] [in a new window]   FIG. 1. Trichomycetes at Misiones and Tierra del Fuego provinces were collected in these areas.

	TRICHOMYCETE SPECIES FROM MISIONES

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View larger version (174K): [in this window] [in a new window]   FIGS. 2–4. Trichomycete species from Misiones. 2. Genistellospora homothallica mature thalli producing trichospores. 3. Harpella tica in the peritrophic membrane of a simuliid larva, producing sigmoid trichospores. 4a. Smittium culisetae thalli with trichospores from a culture isolated from the hindgut of Aedes aegypti larva. 4b. Detail of trichospores of S. culisetae. Scale bars: 2, 3, 4a = 16 µm, 4b = 8 µm.

Harpella tica Lichtwardt FIG. 3

Previous references to H. tica have been from the northwest provinces of Argentina: three sites in Tucumán, two in Salta, and three in Jujuy, in larvae of Simulium exiguum Roubaud, S. romanai, S. wolfhuegelli, S. lahillei and Simulium sp. (Lichtwardt et al 2000). Trichospores of H. tica also were slightly smaller than original description.

Smittium culisetae Lichtwardt FIG. 4a, b

This is a new record for S. culisetae, which was found living in the hindgut of Aedes aegypti L. larvae. The trichospores were long-ovoid and slightly wider near the base with a short collar, and the branches were verticillate. Zygospores were not found. Smittium culisetae has been reported previously in South America from Brazil (Alencar et al 2003) and from Argentina from the mosquito hosts A. aegypti L., A. crinifer (Theobald), Culex dolosus (Lynch Arribálzaga), C. hepperi Casal & García, C. pipiens Wiedemann and Psorophora ferox (Humboldt) (López Lastra 1997, Lichtwardt et al 1999).

Smittium sp.

The only record of gut fungi from Ceratopogonidae larvae in Argentina was Carouxella coemeteriensis reported by Lichtwardt et al (1999). Scarcity of infected specimens from this collection made it impossible to identify this fungus to the species level.

Stachylina sp.

Trichospore shape and size closely resemble S. grandispora, which has been previously reported from the northwestern region of Argentina (Lichtwardt et al 2000).

We also identified Paramoebidium sp. (Amoebidiales) from the hindguts of mayfly larvae from site ARG 89, but the scarce material available made it impossible to identify it to the species level.

	TRICHOMYCETE SPECIES FROM TIERRA DEL FUEGO

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For all the species, their insect hosts, sites, measurements and percent of infection are shown (TABLE II).

Harpella meridianalis Lichtwardt & Arenas FIG. 5a, b

View larger version (138K): [in this window] [in a new window]   FIGS. 5–7. Trichomycetes from Tierra del Fuego. 5a. Harpella meridianalis within peritrophic membrane of a simuliid larvae. 5b. Detail of a coiled trichospore of Harpella meridianalis. 6. Glotzia sp. from hindgut of Ephemeropteran larvae. 7a. Smittium culicis trichospores from hindgut of Ochlerotatus albifasciatus larvae. 7b. S. culicis extruded trichospores. Scale bars: 5a = 46 µm, 5b = 30 µm, 7a = 20 µm, 7b = 10 µm.

Glotzia sp. FIG. 6

This genus was not known previously from South America. Fungal thalli were found in Ephemeroptera nymph hindguts, but it was not possible to identify the species due to the scarcity of material available.

Smittium culicis Manier FIG. 7a, b

This species is widespread but found primarily in mosquito larvae. It has been reported previously from other mosquito species: Culex renatoi Lane & Ramalho, C. apicinus Philippi and Ochlerotatus albifasciatus (Macquart) in Buenos Aires province (Lichtwardt et al 1999, López Lastra 1997). Extruded sporangiospores were found, in some cases along part of the larval midgut; their measures are shown (TABLE II). The present record is a southern extension in range for S. culicis.

Smittium cellaspora Williams FIG. 8a, b

View larger version (137K): [in this window] [in a new window]   FIGS. 8–11. Trichomycetes from Tierra del Fuego. 8a. Smittium cellaspora from a Chironomid larva hindgut, with trichospores. 8b. Detail of a trichospore of Smittium cellaspora with one appendage released (arrow). 9. Thalli with tri-chospores of Smittium imitatum from a hindgut of simuliid larvae. 10a. Stachylina minima within a peritrophic membrane of a Chironomidae larvae; thalli with trichospores. 10b. Detail of trichospores of Stachylina minima. 11. Pennella simulii in hindgut of a simuliid larvae. Thalli with trichospores. Scale bars: 8a = 30 µm, 8b = 20 µm, 9, 10a = 16 µm, 10b = 6 µm, 11 = 20 µm.

Smittium imitatum Lichtwardt & Arenas FIG. 9

This species was found infecting the hindguts of G. antarcticus larvae (Simuliidae) at four different sites. Trichospores were cylindrical but swollen in the middle with a collar. Trichospore sizes were a little longer than the trichospores of S. imittatum reported from Chile by Lichtwardt and Arenas (1996).

Stachylina minima Williams & Lichtwardt FIG. 10a, b

Fungal thalli and trichospores were found in the peritrophic membrane of Chironomidae larvae. This species was recorded previously from Neuquén province in Thienemaniella sp. and Cricotopus sp. (Chironomidae: Orthocladiinae) in Chubut (Lichtwardt et al 1999). The present citation is an extended record for Argentina subantarctic forest and steppe vegetation biogeographic regions. It has been reported before from New Zealand and rediscovered in Argentina from Chironomidae larve in Patagonia. This may be considered to be a disjunct distribution.

Pennella simulii Williams & Lichtwardt FIG. 11

Pennella simulii has not been recorded previously from South America. The closest record was from Costa Rica in Simulium ochraceum Walker (Lichtwardt 1997). In Argentina a closely related species, P. montana, was reported in several species of simuliid larvae (viz. Simulium lahillei, S. romanai, S. wholfhuegelli, S huayrayacu and Simulium sp.) from the northwestern region (Lichtwardt et al 2000). In the present study P. simulii has been identified in G. antarcticus larvae, although only trichospores were observed.

In the hindguts of Plecopteran and Ephemeropteran lar vae we also found Paramoebidium spp. (Amoebidiales) that were different from the Misiones species, but due to scarce material it was not possible to identify it to species level. The percent infection was 16.6% in one of six stoneflies and 7.7% in one of 13 mayflies.

	DISCUSSION

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Our field survey included the Paranaense region at Misiones and the Subantarctic region of Tierra del Fuego. The first is predominantly subtropical rain-forest. In Tierra del Fuego the typical vegetation consists of Nothofagus spp. forest, and the steppe with acidic soils similar to those found in peat (Cabrera and Willink 1973). Paranaense in Misiones and Subantartico in Tierra del Fuego seem to be significant for the diversity of Trichomycetes fungi, although further and more extensive collections should be developed in order to confirm this.

The range of H. tica now extends to Misiones. This fungus was reported from Costa Rica (Lichtwardt 1997), Puerto Rico (White et al 2000) and northwestern Argentina (Lichtwardt et al 2000), where all stream temperatures were relatively warm. Harpella tica was not found in Tierra del Fuego, which had cooler water temperatures (9–15 C) during our survey.

Harpella meridianalis, however, was present in Tierra del Fuego streams in most of the sites sampled and in several simuliid species; previous reports of H. meridianalis were also from cooler waters Lichtwardt and Arenas (1996) from southern Chile and Lichtwardt et al (1999) from Patagonia, Argentina. This difference in temperature preference for the two Harpella species has been noted by Lichtwardt et al (1999).

The warmer waters of Misiones (19.5–24 C) had considerably fewer aquatic insects, at least during the fall when this survey was done, and as a result considerably fewer Trichomycetes. Warmer temperatures may cause acceleration of larval molting. Because with each molt gut fungi are shed and must re-establish themselves in the gut of another larva by means of trichospores, it is possible that in warmer waters the accelerated molting cycles might influence the capacity of some of these fungi to produce sufficient trichospores to maintain reinfestation.

	ACKNOWLEDGMENTS

 
This project was supported by a Grant No. 7129-01 of the National Geographic Foundation (USA). We are indebted to Mr Gustavo Rossi for mosquito identifications and to Mrs Cristina Estivaritz for making the drawings and helping with the plates. We also thank those who kindly provided laboratory space and collecting facilities: Dr Aníbal Amat and Dra Aída Tricio from the Facultad de Ciencias Exactas y Naturales, Universidad de Posadas; Dr Olivero, director of CADIC; Dra Laura Comoglio and Dr Oscar Amim for kindly helping to find laboratory space and other matters; and Mr Julio Escobar for field support, CADIC, Usuhaia, Tierra del Fuego. We also thank the National Park Service of Argentina for providing collecting permits and laboratory facilities, especially Lic. Karina Schiaffino from CIES (Centro de Estudios Tropicales, Parque Nacional Iguazú ) and Lic. Laura Malmierca from Parque Nacional Tierra del Fuego. We greatly appreciate the comments of Dr Robert Lichtwardt who kindly reviewed this manuscript and for his valuable suggestions and advice.

	FOOTNOTES

 
Accepted for publication August 20, 2004.

¹ Corresponding author. E-mail: ccll{at}museo.fcnym.unlp.edu.ar

	LITERATURE CITED

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS TRICHOMYCETE SPECIES FROM... TRICHOMYCETE SPECIES FROM TIERRA... DISCUSSION LITERATURE CITED

 
Alencar YB, Ríos-Velazquez CM, Lichtwardt RW, Hamada, N. 2003. Trichomycetes (Zygomycota) in the digestive tract of arthropods in Amazonas, Brazil. Mem Inst Oswald Cruz 98:799–810.

Cabrera A, Willink A. 1973. Biogeografía de América Latina. OEA Series de Biología No. 13. Washington, D.C.: OEA. 120 p.

Cafaro MJ. 2000. Gut fungi of isopods: the genus Palavascia. Mycologia 92:361–369.[CrossRef]

Campos RE, Maciá A, García JJ. 1995. Variación estacional de las poblaciones de Psorophora spp (Diptera: Culicidae) y detección de sus parásitos y patógenos en la provincia de Buenos Aires, Argentina. Acta Entomol Chilena 19:113–121.

García JJ, Campos RE, Maciá A. 1994. Prospección de enemigos naturales de Culicidae (Diptera) de la selva marginal de Punta Lara (Provincia de Buenos Aires, República Argentina). Rev Acad Colombiana Ciencias Exactas Nat 19:209–215.

———. 1995. Observaciones ecológicas sobre Mansonia indubitans y Ma. titilans (Diptera: Culicidae) y sus enemigos naturales en Punta Lara, Argentina. Rev Soc Entomol Argentina 54:43–50.

Laberye ES, Molloy DP, Lichtwardt RW. 1996. An investigation of Harpellales (Trichomycetes) in New York State blackflies (Diptera: Simuliidae). J Invertebr Pathol 68:293–298.[CrossRef][Medline]

Lichtwardt, RW. 1972. Undescribed genera and species of Harpellales (Trichomycetes) from the guts of aquatic insects. Mycologia 64:167–197.

———. 1986. The Trichomycetes, fungal associates of arthropods. New York: Springer-Verlag. 343 p.

———. 1997. Costa Rican gut fungi (Trichomycetes) infecting lotic insect larvae. Rev Biol Trop 45:1349–1383.

———, Arenas J. 1996. Trichomycetes in aquatic insects from Southern Chile. Mycologia 75:728–734.[CrossRef]

———, Ferrington L Jr, López Lastra CC. 1999. Trichomycetes in Argentinean aquatic insect larvae. Mycologia 9:1060–1082.

———, López Lastra CC, Mazzucchelli MG. 2000. Fungi living in the guts of larval aquatic insects in Northwestern Argentina. Mycologia 92:332–340.[CrossRef]

López Lastra CC. 1997. Primera cita de Smittium culisetae y S. culicis (Trichomycetes: Harpellales) en larvas de mosquitos (Diptera: Culicidae) de la República Argentina. Bol Soc Arg Bot 33:3–6.

———, Mazzucchelli MG, Dikgolz VE. 2003. Temporal changes in the presence of three species of Trichomycetes (Zygomycota: Zygomycotina) in Dipteran aquatic larvae from Argentina. Fungal Diversity 14:85–93.

Maciá A, García JJ, Campos RE. 1995. Bionomía de Aedes albifasciatus y Ae. crinifer (Diptera: Culicidae) y sus enemigos naturales en Punta Lara, Buenos Aires. Neotropica 41:43–50.

———. 1997. Variación estacional de tres especies de Culex (Diptera: Culicidae) y sus parásitos y patógenos en Punta Lara, provincia de Buenos Aires, Argentina. Rev Biol Trop 44/45:267–275.

White MM, Cafaro MJ, Lichtwardt RW. 2000. Arthropod gut fungi from Puerto Rico and summary of Tropical Trichomycetes. Worldwide Caribbean J Sci 36:210–220.

Williams MC. 1982. Smittium cellaspora, a new Harpellales from a chironomid hindgut. Mycotaxon 16:183–186.

Yeboah DO, Undeen AH, Colbo MH. 1984. Phycomycetes parasitizing the ovaries of blackflies (Simuliidae). J Invertbr Pathol 43:363–373.[CrossRef][Medline]

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