Functional feeding groups of Chironomidae (Diptera: Nematocera) and their spatial variation in an intermittent hill stream (Ventana Stream, Buenos Aires, Argentina).

The feeding habits of Chironomidae in hill streams in the pampean region have not been described. In this study, we analyzed the gut contents of this insect family with an aim at establishing their diet in an intermittent stream in the Ventania-Hill system. We sampled three sites with different habitat characteristics (i. e., altitude, substrate type, and current velocity). Of the total of nine taxa were recorded, the only one present at all sites was Corynoneura sp. 1. The food items found were detritus, diatoms, filamentous chlorophytes, euglenophytes, vascular plants, fungi, and animal remains. Most of the taxa could be classified as gathering collectors, with those having a higher proportion of detritus in the gut contents although the guts of Pentaneura nr. cinerea, Cricotopus sp. 1, and Onconeura analiae included high proportions of animal remains. No differences in the feeding habits were attributable to the location in the stream. This research contributes to our understanding of the trophic habits of Chironomidae in an intermittent hill stream system of South America.

Diversity, phenology and voltinism of Chironomidae (Diptera). Neotropical streams as a study model.

Studies of the relationships between the temporal variation of biological phenomena and environmental factors are essential to understanding the dynamics of communities. Phenology is a structuring element and, together with voltinism, is related to timing of reproductive activities. The aim of this study is to ascertain the structure and composition of the Chironomid assemblage and its emergence patterns in relation to the environmental variables through the use of the Chironomid pupal exuviae technique using the Neotropical streams as a model. The streams presented similar species compositions. The highest density of pupal exuviae was recorded during spring and the greatest richness in late summer and early autumn. Chironominae presented greater prevalence throughout the year with oscillations for Orthocladiinae and Tanypodinae. Chironominae and Tanypodinae presented emergence peaks in spring-summer and Orthocladiinae in autumn-winter. Rainfall, photoperiod and water and air temperatures structured the Chironomid assemblage, influencing emergence. Univoltine, bivoltine and multivoltine species were recorded. The species presented interspecific synchronization in emergence peaks at different times of the year.

Yungahelea, a new genus of predaceous midge from northwestern Argentina (Culicomorpha: Ceratopogonidae).

A new monotypic genus and species of predaceous midge from the southernmost area of the Argentinean Yungas, Yungahelea australis Spinelli and Ronderos, is described and illustrated from male and female adults. It belongs to a group containing the Ceratopogonini genera Parabezzia Malloch, Diaphanobezzia Ingram and Macfie, Spinellihelea Borkent, Grogan and Picado, Leptohelea Wirth and Blanton, and Fittkauhelea Wirth and Blanton. Phylogenetic interpretation indicates that Yungahelea is the sister group of Spinellihelea or the clade composed by Parabezzia and Diaphanobezzia.

Histopathological effects of cypermethrin and Bacillus thuringiensis var. israelensis on midgut of Chironomus calligraphus larvae (Diptera: Chironomidae).

Pesticides are extensively used for the control of agricultural pests and disease vectors, but they also affect non-target organisms. Cypermethrin (CYP) is a synthetic pyrethroid used worldwide. Otherwise, bioinsecticides like Bacillus thuringiensis var. israelensis (Bti) have received great attention as an environmentally benign and desirable alternative. In order to evaluate the toxicity of those pesticides, Chironomus calligraphus was selected due to its high sensitivity to some toxicants. Third and fourth instars larvae were exposed to serial dilutions of CYP and Bti to determine LC50 values. In order to evaluate the potentially histopathological alterations as biomarkers, after 96-h of exposure, live larvae were fixed for histological analysis of the mid region of digestive tract. The 96-h LC50 values were 0.52 and 1.506µg/L for CYP and Bti, respectively. Midgut histological structure of the control group showed a single layer of cubical cells with microvilli in their apical surface and a big central nucleus. The midgut epithelium of larvae exposed to a low concentration of CYP (0.037µg/L) showed secretion activity and vacuolization while at high concentration (0.3µg/L) cells showed a greater disorganization and a more developed fat body. On the other hand, Bti caused progressive histological damage in this tissue. Chironomus calligraphus is sensitive to Bti and CYP toxicity like other Chironomus species. The histopathological alterations could be a valuable tool to assess toxicity mechanism of different pesticides.

New species of Pseudosmittia Edwards, 1932 and new records of Allocladius Kieffer, 1913 (Diptera: Chironomidae, Orthocladiinae) from South America.

Three new species of Pseudosmittia Edwards from the Neotropical region, P. satheri, P. larga and P. trapezoidea, are described and figured as males. Allocladiusfortispinatus (Edwards), A. globosus Andersen et al. and A. quadrus Andersen et al. are redescribed on the basis of new material and their geographical distribution updated. A phylogenetic analysis was performed in order to assess the phylogenetic relationships of the new species. As a result, the species P. sœtheri and P. larga are found to be sister species belonging to the angusta group. The species P. trapezoidea is the sister group of the clade ((P. propetropis (P. tropis--P. lamellata)) and belongs to the brevifurcata group sensu lato.

A new species of Macropelopia Thienemann, 1916 (Diptera: Chironomidae) from Southern Brazil.

We report a new species of Macropelopia discovered in southern Brazil, with detailed illustrations and descriptions of all life stages. In addition, we provide an identification key specific to males of neotropical Macropelopia species, together with an amendment to the generic diagnosis.

Diversity of trichomycetes in larval flies from aquatic habitats in Argentina.

Trichomycetes, mainly from nonbiting midge (Chironomidae), mosquito (Culicidae) and black fly (Simuliidae) larvae (Insecta: Diptera), are reported from diverse freshwater environments principally from previously unexplored areas of Argentina. Four new species of Harpellales are described: Austrosmittium patagonicum, A. lenticum, Smittium basiramosum and Legeriomyces lichtwardtii. This is the first report of Austrosmittium spp. from the Americas and the first report of a Legeriomyces from South America. Two other species (Simuliomyces sp. and Harpella sp.) are described but not named. Fourteen previously described species were recovered, and their geographical distribution and host ranges have been extended for Argentina, with Sm. phytotelmatum, Stachylina lentica, St. lotica and St. penetralis being new records for the country.

Prevalence of Harpellales from Chironomidae larvae in phytotelmata from punta Lara Forest, Argentina.

Harpellales (Zygomycota: Trichomycetes) fungi are cosmopolitan obligate inhabitants of the gut of immature insects. A biweekly survey of gut fungi associated with chironomid (Chironomidae: Diptera) larvae living in the impounded water from Eryngium cabrerae (Apiaceae) phytotelmata from Punta Lara forest, Argentina, was done Jan 2003-Dec 2004. Two species of Harpellales were associated with chironomid larvae, Smittium phytotelmatum in the hindgut of Polypedilum sp. and Stachylina lentica in the midgut of both Polypedilum sp. and Metriocnemus eryngiotelmatus. No statistically significant differences were recorded in the prevalence of these Harpellales between seasons. Environmental variables (temperature, rainfall and relative humidity), impounded water volume, pH and chironomid larval density did not have an effect on the prevalence of the Trichomycetes.

New species and emendations of Orphella: taxonomic and phylogenetic reassessment of the genus to establish the Orphellales, for stonefly gut fungi with a twist.

We consolidate and present data for the sexual stages of five North American species of Orphella, fungal members of trichomycetes previously classified within Harpellales. Three species emendations accommodate the newly recognized characters, including not only the coiled zygospores and accompanying cells but also other morphological traits not provided in the original descriptions for O. avalonensis, O. haysii, and O. hiemalis. We describe three new species, Orphella cataloochensis from both the Smoky Mountains in USA and two provinces in Canada as well as O. pseudoavalonensis and O. pseudohiemalis, both from the Cascade Range, in Oregon, USA. Key morphological features for all known species are summarized and reviewed, with illustrations of some of the North American taxa to update and supplement the literature. The entire suite of morphological characters is discussed, with emphasis on species relationships and hypotheses on possible vicariant origins. We also present a molecular phylogeny based on nuc rDNA 18S and 28S, which supports Orphella as a lineage distinct from Harpellales, and we establish a new order, Orphellales, for it. With the combination of sexual features, now known for 12 of the 14 species of Orphella, and new molecular data, the group is now better characterized, facilitating and hopefully also promoting future studies toward a better understanding of their relationships, origins, and evolutionary history as stonefly gut-dwelling fungi.

Trichomycete insect symbionts in Great Smoky Mountains National Park and vicinity.

Collections of trichomycete symbionts of larval aquatic insects in Great Smoky Mountains National Park and vicinity in the southern Appalachian region of the USA resulted in finding many taxa of Harpellales, including an unusual new monotypic genus, Barbatospora ambicaudata in Simuliidae, and five new species in Thaumaleidae or Chironomidae, Harpellomyces montanus, Smittium lentaquaticum, Sm. minutisporum, Stachylina gravicaudata and St. stenospora. In addition a new species of Amoebidium (Amoebidiales), A. appalachense, attached to the anal tubules of bloodworms (Chironomidae) is described. Axenic cultures of three of the new taxa were obtained, plus Sm. culisetae. Fourteen identified species representing 13 genera of previously known Harpellales are recorded from Plecoptera, Ephemeroptera and Diptera, as well as a new Dipteran host record for an unidentified harpellid that was found in a Blephariceridae. Also identified were Paramoebidium corpulentum and many undetermined species of Paramoebidium (Amoebidiales) from four orders of aquatic insect larvae. The occurrence of an Enterobryus species in Diplopoda and another Eccrinales from an aquatic beetle is noted. Amoebidiales,

Yungahelea, a new genus of predaceous midge from northwestern Argentina (Culicomorpha: Ceratopogonidae)

ABSTRACT A new monotypic genus and species of predaceous midge from the southernmost area of the Argentinean Yungas, Yungahelea australis Spinelli and Ronderos, is described and illustrated from male and female adults. It belongs to a group containing the Ceratopogonini genera Parabezzia Malloch, Diaphanobezzia Ingram and Macfie, Spinellihelea Borkent, Grogan and Picado, Leptohelea Wirth and Blanton, and Fittkauhelea Wirth and Blanton. Phylogenetic interpretation indicates that Yungahelea is the sister group of Spinellihelea or the clade composed by Parabezzia and Diaphanobezzia.

A new species of Metriocnemus van der Wulp (Diptera: Chironomidae) with a tentative phylogeny of the genus.

The male and female of the new species Metriocnemus puna sp. n from the Argentinean Puna are described and illustrated. A parsimony analysis including 24 well-described species of the genus plus the new species based on the adult male was conducted in order to access the phylogenetic position of the new species and to provide the first phylogenetic hypothesis for the genus.

Entomophthora ferdinandii (Zygomycetes: Entomophthorales) causing natural infections of Musca domestica (Diptera: Muscidae) in Argentina.

The identity and activity of an entomopathogenic fungus belonging to the Entomophthora muscae species complex and infecting Musca domestica in poultry houses from La Plata, Argentina, is reported. Entomophthora caused natural infections between September 2001 and September 2003. Primary conidia of this fungus were on average 29.5 +/- 1.2 x 23.4 +/- 2.4 microm and contained, on average, 10.5 +/- 0.1 nuclei (range: 7-15) with an average diameter of 4.8 +/- 0.1 microm. This fungus is identified as E. ferdinandii Keller (this specific epithet includes a nomenclaturally required spelling correction); this is a first record of E. ferdinandii in South America and of any member of the E. muscae species complex from flies in Argentina.

A new species of Metriocnemus van der wulp (diptera: chironomidae) with a tentative phylogeny of the genus

The male and female of the new species Metriocnemus puna sp. n from the Argentinean Puna are described and illustrated. A parsimony analysis including 24 well-described species of the genus plus the new species based on the adult male was conducted in order to access the phylogenetic position of the new species and to provide the first phylogenetic hypothesis for the genus.