Simuliidae Larvae Research Articles

Бактеріальне зараження личинок мошок та використання бакпрепаратів для контролю чисельності симуліїд

Considerable attention is paid to the biological method of controlling the number of blood-sucking insects, as it is highly selective, effective and environmentally safe. 340 reservoirs were examined within Volyn Polissia, among which 86 (14,9%) contained Simuliidae larvae with signs of bacterial lesion. Damaged larvae were recorded in small rivers and ameliorative canals, most of which, 71,5%, were mesosaprobic in terms of water quality. Bacterial infection was detected in the larvae of 10 species: S. pusillum, S. nigrum, S. equinum, S. erythrocephalum, S. ornatum, S. dolini, S. noelleri S. paramorsitans, S. promorsitans, S. morsitans. Оn Volyn Polissia a study was conducted on the effectiveness of reservoirs delarvation with three preparations based on Bacillus thuringiensis H14 bacteria - bactoculicide, bactolarvicide and BLP-2477. Experiments were carried out in ameliorative canals with a bed up to 2 m wide, 0.5 m deep and with a current speed of 0.7 m/s, which were densely populated by preimaginal phases of black flies. Treatment of the reservoir with preparations was carried out in two ways. The first consists in a one-time introduction of the entire dose, the second - in a gradual introduction of the dose over 6 and 24 hours. It was established that a single application of the entire dose of the preparation ensures only partial death (up to 75%) of black flies. An uneven death of larvae was registered in the entire area of treatment. The method of gradual introduction of the preparation, when it is washed out over 6 or 24 hours, is more effective (death of larvae up to 100%). To the quantity control of the black flies pre-imaginal phases development, preparations BLP-2477 and bactolarvicide are recommended as the most effective. The optimal dose for the death of black flies larvae at a distance of up to 1.5 km in ameliorative canals with width of up to 2 m, depth of 0.5 m and a flow speed of 0.7 m/s should be considered 400 g of the preparation. The deaths of non-target hydrobionts, caddisflies, mayflies, molluscs, and fishes were not registered. Key words: Simuliidae, Bacillus thuringiensis, reservoirs delarvation, bactoculicide, bactolarvicide, BLP-2477.

Occurrence and Characterization of Small Microplastics (

This study is the first to investigate the ingestion of microplastics (MPs), plasticizers, additives, and particles of micro-litter < 100 μm by larvae of Simuliidae (Diptera) in rivers. Blackflies belong to a small cosmopolitan insect family whose larvae are present alongside river courses, often with a torrential regime, up to their mouths. Specimens of two species of blackfly larvae, Simulium equinum and Simulium ornatum, were collected in two rivers in Central Italy, the Mignone and the Treja. Small microplastics (SMPs, <100 μm), plasticizers, additives, and other micro-litter components, e.g., natural and non-plastic synthetic fibers (APFs) ingested by blackfly larvae were, for the first time, quantified and concurrently identified via MicroFTIR. The pretreatment allowed for simultaneous extraction of the ingested SMPs and APFs. Strong acids or strong oxidizing reagents and the application of temperatures well above the glass transition temperature of polyamide 6 and 6.6 (55–60 °C) were not employed to avoid further denaturation/degradation of polymers and underestimating the quantification. Reagent and procedural blanks did not show any SMPs or APFs. The method’s yield was >90%. Differences in the abundances of the SMPs and APFs ingested by the two species under exam were statistically significant. Additives and plasticizers can be specific to a particular polymer; thus, these compounds can be proxies for the presence of plastic polymers in the environment.

Black fly (Diptera:Simuliidae) larvae body size variation along an altitude gradient in the Itatiaia National Park, Brazil

According to Bergmann’s Rule, individuals who inhabit higher altitudes tend to be larger in body mass or size, when compared with individuals of the same taxon who inhabit lower altitude places. Black flies are insects of great medical and veterinary importance due to its blood-sucking habit, becoming subject of studies regarding its bionomics, ecology and taxonomy. Studies approaching the influence of the altitude gradient in the morphology of Diptera: Simuliidae larvae are scarce in the literature, therefore, this study aimed to investigate the influence of altitude gradient in the morphology of Diptera: Simullidae larvae in Itatiaia National Park, RJ, and thus verify if Bergmann’s Rule is applicable to these organisms. Black fly larvae were sampled from four sites during periods of March and May 2013. From each site 30 larvae were measured, and these lengths were later compared between sites using Kruskal-Wallis, which showed a significant difference (P&lt;.05) among sites from lower altitudes in relation to those of higher elevations, what was corroborated using a cluster analysis. The altitude was related to larval size using a linear regression, showing a positive correlation between these variables, thus corroborating Bergmann’s rule for Black flies.

Prey availability and selective feeding of sea trout (Salmo trutta L., 1758) fry stocked in small forest streams

Summary The food base and stomach contents of stocked sea trout (Salmo trutta) fry were determined in the first 4 months (April–August 2010) of life in two small lowland streams after resorption of the yolk sac. In each stream, 600 individual trout were released in a 200 m stocking-section. The macrozoobenthos given as a food base for the fry were collected once a month from the streams using a bottom scraper. Three subsamples of macrozoobentos were considered as one sample from the stocking-section. On the same day, 50 stocked fry were captured in each stream using electric fishing gear. Preferred food components were usually the taxa represented by number in a given stream in a particular month. Width size range of the prey in fish stomachs in May was from 0.10 to 1.47 mm, and from 0.11 to 3.78 mm in August. All food items found in both streams during the study months were also represented in intensity in the fish: Cyclopoida, and larvae of Baetidae and Chironomidae. Almost all Helodidae and Simuliidae larvae as well as the majority of Limoniidae and Nemouridae larvae were available as food each month.

The application of predictive modelling for determining bio-environmental factors affecting the distribution of blackflies (Diptera: Simuliidae) in the Gilgel Gibe watershed in Southwest Ethiopia.

Blackflies are important macroinvertebrate groups from a public health as well as ecological point of view. Determining the biological and environmental factors favouring or inhibiting the existence of blackflies could facilitate biomonitoring of rivers as well as control of disease vectors. The combined use of different predictive modelling techniques is known to improve identification of presence/absence and abundance of taxa in a given habitat. This approach enables better identification of the suitable habitat conditions or environmental constraints of a given taxon. Simuliidae larvae are important biological indicators as they are abundant in tropical aquatic ecosystems. Some of the blackfly groups are also important disease vectors in poor tropical countries. Our investigations aim to establish a combination of models able to identify the environmental factors and macroinvertebrate organisms that are favourable or inhibiting blackfly larvae existence in aquatic ecosystems. The models developed using macroinvertebrate predictors showed better performance than those based on environmental predictors. The identified environmental and macroinvertebrate parameters can be used to determine the distribution of blackflies, which in turn can help control river blindness in endemic tropical places. Through a combination of modelling techniques, a reliable method has been developed that explains environmental and biological relationships with the target organism, and, thus, can serve as a decision support tool for ecological management strategies.

Observation methods for species in Harpellales using Simuliidae larvae

Observation methods for species in Harpellales using Simuliidae larvae

Life-History Attributes of the Imperiled Frecklebelly Madtom,Noturus munitus(Siluriformes: Ictaluridae), in the Cahaba River System, Alabama

Noturus munitus (Frecklebelly Madtom) is a diminutive catfish with a disjunct distribution across the southeastern United States in large rivers and tributaries of the Mobile Basin and Pearl River drainage. Its distribution has contracted since extensive river modification began throughout its range in the 1960s, and it is likely extirpated from the Alabama River. We collected 242 specimens of N. munitus from a gravel island in the Cahaba River on the Coastal Plain in Alabama from May 2005 to March 2007 to examine life-history characteristics. Adults were associated with fast flow over large gravel at depths of 0.5–1.0 m. Young (<23 mm) were found at water depths of 0.4–0.5 m. Gonad development indicated a reproductive season from May to August, with collection of young-of-the-year in June and July supporting a mid- to late-summer spawn. Stomach content analysis revealed a diet similar to other Noturus species and dominated in volume by Baetidae nymphs (31.2%), Hydropsychidae larvae (20.3%), and Simuliidae larvae (19.7%). Some seasonal and sex differences in diet were apparent. Relative fecundity data indicate that N. munitus is one of the most fecund madtoms of the subgenus Rabida (mean of 30.6 mature oocytes) studied thus far. Few males were found in riffles during summer, and no young were found in riffles outside summer, indicating potential sex and size differences in seasonal habitat use. This knowledge is important for conservation of the species.

Feeding Habits of Torrent Ducks (Merganetta Armata Armata) in Nahuel Huapi National Park, Argentina

The Torrent Duck (Merganetta armata) is a little-known species that feeds on benthic invertebrates in fast-flowing mountain rivers and streams from Venezuela to Tierra del Fuego. In Argentina the species is classified as Threatened but basic studies of its resource requirements are necessary for conservation. Prey selection by adult Torrent Ducks was investigated by comparing the proportion of prey species in duck faeces with the proportion available in the benthos. Faeces and benthos were sampled seasonally over one year, from four territories in the Manso River Basin, Nahuel Huapi National Park, northwestern Argentine Patagonia. Filter feeding Simuliidae larvae (Diptera, 41–76% number of total prey) were consumed in greater proportion than their abundance. In Arroyo Blanco, an oligotrophic stream, Simuliidae were absent and the most important prey were Gripopterygidae larvae (Plecoptera, 53%) and Blephariceridae larvae (Diptera, 23%). Simuliidae may be easy prey because, like other filter feeders, they feed in exposed places. However, where these filtering species are rare or absent (as in Arroyo Blanco), ducks consume other prey. The results show that Torrent Ducks exhibit a versatile feeding behavior, indicating that the species can adjust to changes in the benthos without disappearing in a given environment.

Midge-inferred Holocene climate history of two subalpine lakes in southern British Columbia, Canada

To investigate postglacial environmental changes in both the coastal and interior wet belts of British Columbia, fossil midges were analysed from two subalpine lakes, one adjacent to the lower Fraser canyon (Frozen Lake), and the other in Mount Revelstoke National Park (Eagle Lake). The midge stratigraphy for Frozen Lake revealed an abundance of rheophilous chironomid taxa and Simuliidae larvae, refecting the presence of an inflowing stream. An abundance of Chaoborus mandibles and Microtendipes during the early Holocene (c. 10100–7700 14C years BP, c. 11500–8500 cal. years BP) suggests warmer temperatures. A subsequent decline in the warm indicators and relative increases in cold stenotherms (Heterotrissocladius and Diamesa) indicate cooling until present day. This climate reconstruction is consistent with other quantitative and qualitative evidence for past climatic change in southern British Columbia. At Eagle Lake the warm indicators, Dicrotendipes and Polypedilum, are seen in the early Holocene (c. 8500–6730 14C years BP, c. 9600–7600 cal. years BP), but are absent during the mid-Holocene when cooler temperatures probably prevailed. In the late Holocene (c. 3800 14C years BP to present, c. 4200 cal. years BP to present) there is a resurgence of warm indicators, which contrasts with the evidence of continued cooling typically seen in reconstructions of southern British Columbia summer temperatures. The Eagle Lake record therefore appears to be anomalous. Multiproxy and multisite investigations are needed to reconstruct Holocene climatic changes more reliably.

Trichomycetes (Zygomycota) in the digestive tract of arthropods in Amazonas, Brazil.

Eight species of Harpellales and three species of Eccrinales (Zygomycota: Trichomycetes) were found associated with the digestive tract of arthropods from terrestrial and aquatic environments in the central Amazon region of Brazil. New species of Harpellales include: Harpella amazonica, Smittium brasiliense, Genistellospora tropicalis in Simuliidae larvae and Stachylina paucispora in Chironomidae larvae. Axenic cultures of S. brasiliense were obtained. Probable new species of Enterobryus (Eccrinales), Harpella, and Stachylina (Harpellales) are described but not named. Also reported are the previously known species of Eccrinales, Passalomyces compressus and Leidyomyces attenuatus in adult Coleoptera (Passalidae), and Smittium culisetae and Smittium aciculare (Harpellales) in Culicidae and Simuliidae larvae, respectively. Comments on the distribution of some of these fungi and their hosts in the Neotropics are provided.

SUMMER FOOD HABITS OF HARLEQUIN DUCKS IN EASTERN NORTH AMERICA

We collected feces of breeding Harlequin Ducks (Histrionicus histrionicus) from interior rivers of Northern Québec, Labrador and Newfoundland to document their summer food habits. We obtained 42 samples from 50 ducks. All samples contained recognizable food items, and the mean number of taxa identified per sample was 3.6 (SD = 1.6, range = 1–7). Overall, a total of 10,222 organisms from 25 taxa were identified. Nearly all (99.7%) food items were insects; the rest were mollusks and mites. Among insects, Simuliidae larvae were the most common food item, representing 87.2% of all prey counted. Other insects had low relative frequencies, the highest being Trichoptera with only 8.0%. However, in terms of frequency of occurrence, many insects were well represented: Trichoptera (83.3%), Ephemeroptera (64.3%), Diptera (61.9%), Plecoptera (33.3%), Coleoptera (11.9%), and Heteroptera (9.5%). Although Simuliidae larvae may represent the most important food taken in terms of absolute numbers, the relative importance of Trichoptera may be much higher in terms dry weight. These results are consistent with observations that Harlequin Ducks usually feed on the bed of fast stretches of rivers, and occasionally in slow-moving waters.

Fungi living in the guts of larval aquatic insects in northwestern Argentina

Nine species of Harpellales (Zygomycota: Trichomycetes) and one species of Amoebidiales are reported from the northwestern provinces of Tucuman, Salta, and Jujuy in Argentina. New species included Smittium urbanum and Stachylina jujuyensis from Chironomidae larvae and Paramoebidium argentinense from Ephemeroptera nymphs. Harpella tica, previously known only from Costa Rica and Puerto Rico, was found in Simuliidae larvae, sometimes in the same streams with H. meridianalis, a fungus common in simuliids in more southern regions of Argentina and Chile. The warmer stream waters in the northwestern provinces had an impoverished insect fauna and we found fewer species than in the colder streams of Patagonia.

Fungi Living in the Guts of Larval Aquatic Insects in Northwestern Argentina

Nine species of Harpellales (Zygomycota: Trichomycetes) and one species of Amoebidiales are reported from the northwestern provinces of Tucu- man, Salta, and Jujuy in Argentina. New species in- cluded Smittium urbanum and Stachylina jujuyensis from Chironomidae larvae and Paramoebidium argen- tinense from Ephemeroptera nymphs. Harpella tica, previously known only from Costa Rica and Puerto Rico, was found in Simuliidae larvae, sometimes in the same streams with H. meridianalis, a fungus com- mon in simuliids in more southern regions of Argen- tina and Chile. The warmer stream waters in the

HIGH-DOSAGE TREATMENT OF A QUEBEC STREAM WITH BACILLUS THURINGIENSIS SEROVAR. ISRAELENSIS: EFFICACY AGAINST BLACK FLY LARVAE (DIPTERA: SIMULIIDAE) AND IMPACT ON NON-TARGET INSECTS

AbstractA typical lake outlet of the Canadian Shield was treated for 15 min with a high dose (5.28 g/L s−1 of discharge) of Teknar®, a commercial formulation of Bacillus thuringiensis serovar. israelensis. Efficacy on Simuliidae larvae and impact on non-target aquatic insects of this stream were monitored using drift nets, counting plates, and artificial turf substrates along a 1000-m section downstream of the site of application. Compared with a 4-day pre-treatment average for 12-h sampling periods, drift of Simuliidae increased from 64 to 92 ×, with shorter peaks of 133–184 ×, 2–6 h after treatment. There was no evident drift increase in larvae of Ephemeroptera, Plecoptera, Trichoptera, Chironomidae, or dipterous pupae, but larvae of Blephariceridae (Diptera) were severely affected as their drift was increased by up to 50 × and remained high for 3 days. After 30 h the mortality of Simuliidae on counting plates ranged from 95 to 82% in the first 300 m, with detachment rates of 78.5–46.5%. Densities of non-target insect larvae were not reduced on the artificial substrates, except for 2 genera of Chironomidae (Eukiefferella and Polypedilum) which were reduced 26 to 39% of their original density. Drifting larvae of 1 chironomid genus (Phaenopsectra) also showed symptoms of toxemia by B.t.i. The main impact of the treatment was thus seen in 2 Nematocera families (Chironomidae and Blephariceridae) which were mainly exposed to B.t.i. sedimented on the bottom of the stream or attached to periphyton growing on rocks.

TOXICITY OF BACILLUS THURINGIENSIS VAR. KURSTAKI TO AQUATIC INSECTS

AbstractRepresentative aquatic insects, larvae of Simuliidae, Chironomidae, Trichoptera, Megaloptera, and nymphs of Ephemeroptera and Plecoptera, were tested for susceptibility to continuous exposure to Bacillus thuringiensis Berliner var. kurstaki at 4.3, 43, and 430 IU/mL. Only Simulium vittatum was affected, and at the highest concentration. Effects on other organisms, particularly Prosimulium fuscum/mixtum, were suggested. The lowest of the concentrations tested was twice the worst-case transitory concentration peaks expected in water from aerial forest spraying at 30 BIU/ha. Spray buffer zones around water bodies are unnecessary at this spray rate.

Filter feeding in larvae of Simuliidae (Diptera: Culicomorpha): aspects of functional morphology and hydrodynamics

The feeding mechanism of simuliid larvae is further elucidated by detailed study of the nature and speed of cephalic fan and mouthpart movements, and examination of water flow around larvae. Photographic observations of artificial particles flowing past Simulium vittatum Zett. larvae show the body and head to be highly streamlined and water flow to be laminar over the larva. Dissections and cinephotography show cephalic fan closure to be initiated and controlled by rotation and medial movement of the torma. As the primary fan closes, the median and secondary fans close and form raised sides to the primary fan. Sharp movements made during opening and closing of the fan suggest the presence of "click mechanisms."One cephalic fan closes and adducts every 0.231 s, and for the period analyzed, one or other fan was closed 28% of the time. It is suggested that the time fans are closed should be included in calculations of simuliid larval feeding efficiencies. Larvae with slower mouthpart movements may filter more efficiently than those with faster movements.Laminar flow through and cross-sectional shape of fan rays produce optimal flow for filtration. Probably turbulent flow at higher velocity may explain observed decreases in feeding efficiencies. Behaviour, body shape, and structure of simuliid larvae are highly adapted for optimal water flow over body and fans, even when gross flow in the habitat is turbulent.

Stonefly (Plecoptera) Food Habits and Prey Preference in the Dolores River, Colorado

Gut contents of 1013 stonefly nymphs, comprising nine species, from the Dolores River, Colorado, were analyzed from December 1974-October 1975 and compared with food availability. Pteryonarcyids ingested large quantities of detritus and some moss, moss being a substantial food item in later instar Pternarcella badia nymphs. Perlodids fed primarily on chironomids and simuliids, although Isoperla fulva also ingested mayflies in June. Claassenia sabulosa remained carnivorous throughout development: young nymphs ingested chironomids and small mayflies and larger nymphs ingested caddisflies and mayflies. Horn's Coefficient of Dietary Overlap indicated significant overlap between all perlodids and chloroperlids. It also showed significant overlap between small and large C. sabulosa nymphs, yet selection of different prey sizes indicated resource partitioning. A comparison of food habits with the Gunnison River stoneflies indicated differences between the diets of large and small Claassenia sabulosa, with chironomids comprising large percentages of the diet for both size classes in the Gunnison River and smaller nymphs in the Dolores. Mayflies were important prey for larger individuals in the Dolores River. These differences could be attributed to different prey populations in each river and/or to availability of prey in the particular size that each predator preferred. In both rivers, Chironomidae and Simuliidae larvae were the major prey in the guts of Cultus aestivalis and Isoperla fulva. This prey specificity may have been due to decreased availability of smaller individuals in the other major prey groups or a difficulty in capture of larger prey organisms. INTRODUCTION Fuller and Stewart (1977) discussed stonefly food habits and showed that seasonal-developmental shifts occurred in nymphal diets and food preferences among 10 species in the Gunnison River, Colorado. They also addressed dietary overlap, prey size electivity, resource partitioning and diel periodicity in feeding. Earlier studies by Muttkowski and Smith (1929), Hynes (1941), Brinck (1949), Jones (1950), Mackereth (1957) and Richardson and Gaufin (1971) dealt only with gut analyses and descriptive aspects of feeding. More recent studies have reported seasonal fluctuations in diets (Tarter and Krumholz, 1971; Sheldon, 1972; Vaught and Stewart, 1974; Cather and Gaufin, 1975), yet only one (Siegfried and Knight, 1976) contains information on prey availability. When feeding habits of specific taxa are compared between river systems, prey availability data are essential before any conclusions can be drawn about a predator's preference or selection for particular prey taxa. This article describes a study made of food habits and prey selection by nine stonefly species in the Dolores River, Colo. The research was done concurrently with that reported by Fuller and Stewart (1977) on the Gunnison River, Colo., and comparisons will be made for the eight species encountered in both rivers December 1974 October 1975. STUDY RIVER AND METHODS Headwaters of the Dolores River originate on the S slope of the San Miguel mountains in southwestern Colorado. The West and East Forks converge about 13 miles above Dolores, and the river flows southwestward to Dolores, thence north' Study supported in part by U.S. Environmental Protection Agency Traineeship #T900115 and North Texas State University Faculty Research Fund Grants # 34866 and 34905. 2 Present address: Department of Zoology, University of Toronto, Toronto, M5S, lAl, Ontario, Canada.

Some Factors Affecting Drift Rates of Baetis and Simuliidae in a Large River

Effects of eight factors on the drift rates of Baetis nymphs and Simuliidae larvae were tested with multiple regression analyses. Illumination, population density of all other organisms and temperature had significant influences on drift rates of both organisms. Turbidity and water—level fluctuations were related to changes in drift rates indirectly through influence upon light penetration and population density, respectively. Dissolved—oxygen concentration, calendar date, and depth of water at the sample site did not clearly affect drift rates of either organism. In areas where population densities were high, the eight factors tested accounted for 65% to 81% of the variability observed in drift rates. Maximum drift rates were 170 x 106 Baetis sp. nymphs (63.2 kg) and 10.9 x 106 Simuliidae larvae (5.4 kg) per day.

Zygospores and Spore Appendages of Harpella (Trichomycetes) from Larvae of Simuliidae

Larvae of black flies (Simuliidae) serve as hosts for a number of Trichomycetes. Not infrequently several taxa of these fungi occur simultaneously in individual larvae. The larval hindguts may contain, for instance, species of the genus Paramoebidium (Amoebidiales) to? gether with species of one or more genera of the Genistellaceae (Harpellales), while their midguts frequently harbor Harpella melusinae Leger & Duboscq. This rich representation of Trichomycetes is not unusual in black fly populations in the United States, nor in some species in France (Tuzet and Manier, 1955). The Trichomycetes inhabiting the hindguts of black fly and other Diptera larvae will be the subject of subsequent publications. This paper is concerned with the genus Harpella. Zygospores are documented for the first time as well as structural features of the peculiar appendages borne by the asexual spores.1 Considerable field work with Harpella during the past 6 years has convinced me that the genus, as we now know it, consists of a single species inhabiting a variety of simulid larvae. Harpella melusinae was described by Leger and Duboscq in 1929. It was attached by means of a holdfast to the peritrophic membrane of Simulium ornatum Meig. The thalli were described as simple, at first uninucleate becoming coenocytic, then by septation dividing into uni? nucleate cells. From the distal end of each cell arose a lateral, curved spore (conidium) that served as a means of asexual reproduction. No mention of spore appendages was made in their first paper, but Leger and Gauthier in 1935 illustrated the spore of H. melusinae and showed it bearing 4 basal appendages. Leger and Duboscq (1929) described two situations that they inter? preted as being sexual processes. The first, termed automixis, involved

Zygospores and Spore Appendages of Harpella (Trichomycetes) from Larvae of Simuliidae

Zygospores and Spore Appendages of Harpella (Trichomycetes) from Larvae of Simuliidae