Phylogeny of Culicomorpha (Diptera)

The phylogeny of the families of Culicomorpha and their closest relatives are cladistically reinvestigated adding published information from several sources. A revised data matrix is presented and some characters are discussed. Different outgroups and options used, characters unordered or ordered, the results reweighted or not and the results discussed. Nymphomyiidae in all cladograms, alone or together with Thaumaleidae, forms the sister group of the traditional Culicomorpha and should be included in this infraorder as suggested by others. Superfamily Chironomoidea is not monophyletic as Thaumaleidae or Nymphomyiidae + Thaumaleidae form the sister group to the remaining traditional Culicomorpha. The mutual relationships of Chironomidae, Simuliidae and Ceratopogonidae are variable between cladograms. They form a monophyletic group with Chironomidae and Simuliidae as sister groups when characters are unordered and reweighted or when some characters are ordered, others unordered and the result reweighted. When the characters are ordered, or when a combination of ordered and unordered are used they form a Hennigian comb with the phyletic sequence Chironomidae/Ceratopogonidae/Simuliidae. When characters are ordered and reweighted the phyletic sequence is Chironomidae/Simuliidae/Ceratopogonidae. Culicoidea is monophyletic in all cladograms, but the division into superfamilies is not warranted.     

Predator-prey interactions on the wing: aerobatics and body size among dance flies and midges

Male dance flies (Diptera: Empididae) are major predators of mating swarms of male nonbiting midges (Diptera: Chironomidae). Studies have indicated that chironomid midges are excellent fliers with extraordinarily high wing muscle power, acceleration and tortuosity for their size. We compared the relative flight performance and morphometrics of male empidsEmpis tesselatta Meigen and their prey, Chironomus plumosus L., in a series of laboratory and field studies. High-speed digital video camera footage revealed that there were no significant differences between predator and prey in terms of straight-line acceleration or maximum flight velocity, although the mean speed of empids was higher. In curved flight, measured as tortuosity, the smaller chironomids held a considerable advantage over their larger predators. Flight muscle ratio (e.g. flight muscle mass/body mass) of chironomids was also greater in chironomids than in empids. In field studies, small male chironomids suffered much lower levels of predation than large males. This result is consistent with the prediction of small midges being less likely to be captured because of superior aerobatics, although we are unable to exclude empirically that empids select large male midges. We discuss the possible mechanisms of prey capture by empids given the greater manoeuvrability of their prey, the coevolutionary dynamics of flight performance and the apparent selective advantage of small size in male chironomids. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.      

Parasites as prey in aquatic food webs: implications for predator infection and parasite transmission

While the recent inclusion of parasites into food‐web studies has highlighted the role of parasites as consumers, there is accumulating evidence that parasites can also serve as prey for predators. Here we investigated empirical patterns of predation on parasites and their relationships with parasite transmission in eight topological food webs representing marine and freshwater ecosystems. Within each food web, we examined links in the typical predator–prey sub web as well as the predator–parasite sub web, i.e. the quadrant of the food web indicating which predators eat parasites. Most predator– parasite links represented ‘concomitant predation’ (consumption and death of a parasite along with the prey/host; 58–72%), followed by ‘trophic transmission’ (predator feeds on infected prey and becomes infected; 8–32%) and predation on free‐living parasite life‐cycle stages (4–30%). Parasite life‐cycle stages had, on average, between 4.2 and 14.2 predators. Among the food webs, as predator richness increased, the number of links exploited by trophically transmitted parasites increased at about the same rate as did the number of links where these stages serve as prey. On the whole, our analyses suggest that predation on parasites has important consequences for both predators and parasites, and food web structure. Because our analysis is solely based on topological webs, determining the strength of these interactions is a promising avenue for future research.     

Seasonal variation in abundance and diversity of eavesdropping frog‐biting midges (Diptera,Corethrellidae) in a neotropical rainforest

1. In the tropics, precipitation patterns result in seasonal fluctuations in the abundance and distribution of plant and animal species. Tropical predators and parasites are therefore faced with seasonal changes in prey and host availability. 2. This study investigates the seasonal interaction among a specialised ectoparasite, eavesdropping frog‐biting midges (Corethrella spp.), and their anuran hosts, examining how the abundance and diversity of the frog‐biting midge community fluctuate between the rainy (host abundant) and dry (host sparse) seasons. 3. Midges were captured in both the rainy and dry seasons using acoustic playbacks of calls from a common frog species that breeds during the rainy season, the túngara frog (Engystomops, Physalaemus, pustulosus). During the dry season túngara frog choruses are absent. To explore seasonal shifts in host preference or changes in the midge community due to host specificity, midges were also captured using playbacks of calls from a frog that breeds during the dry season, the pug‐nosed tree frog (Smilisca sila). 4. While the overall abundance of midges decreased in the dry season, only slight differences in the relative abundance between midge species were found. These results suggest that midge populations can shift between hosts as they become available across seasons, allowing adult populations of frog‐biting midges to persist year‐round. To overcome the challenge of detecting and localising different host species, it is proposed that frog‐biting midges have evolved a generalised acoustic template, allowing them to respond to a broad range of available hosts, regardless of seasonal host composition.     

Food Web Structure in a Harsh Glacier-Fed River

Glacier retreat is occurring across the world, and associated river ecosystems are expected to respond more rapidly than those in flowing waters in other regions. The river environment directly downstream of a glacier snout is characterised by extreme low water temperature and unstable channel sediments but these habitats may become rarer with widespread glacier retreat. In these extreme environments food web dynamics have been little studied, yet they could offer opportunities to test food web theories using highly resolved food webs owing to their low taxonomic richness. This study examined the interactions of macroinvertebrate and diatom taxa in the Ödenwinkelkees river, Austrian central Alps between 2006 and 2011. The webs were characterised by low taxon richness (13–22), highly connected individuals (directed connectance up to 0.19) and short mean food chain length (2.00–2.36). The dominant macroinvertebrates were members of the Chironomidae genus Diamesa and had an omnivorous diet rich in detritus and diatoms as well as other Chironomidae. Simuliidae (typically detritivorous filterers) had a diet rich in diatoms but also showed evidence of predation on Chironomidae larvae. Food webs showed strong species-averaged and individual size structuring but mass-abundance scaling coefficients were larger than those predicted by metabolic theory, perhaps due to a combination of spatial averaging effects of patchily distributed consumers and resources, and/or consumers deriving unquantified resources from microorganisms attached to the large amounts of ingested rock fragments. Comparison of food web structural metrics with those from 62 published river webs suggest these glacier-fed river food web properties were extreme but in line with general food web scaling predictions, a finding which could prove useful to forecast the effects of anticipated future glacier retreat on the structure of aquatic food webs.     

Determinants of abundance and effects of blood-sucking flying insects in the nest of a hole-nesting bird

Compared to non-flying nest-dwelling ectoparasites, the biology of most species of flying ectoparasites and its potential impact on avian hosts is poorly known and rarely, if ever, reported. In this study we explore for the first time the factors that may affect biting midge (Diptera: Ceratopogonidae) and black fly (Diptera: Simuliidae) abundances in the nest cavity of a bird, the hole-nesting blue tit Cyanistes caeruleus, and report their effects on adults and nestlings during reproduction. The abundance of biting midges was positively associated with nest mass, parental provisioning effort and abundance of blowflies and black flies, while negatively associated with nestling condition. Furthermore, a medication treatment to reduce blood parasitaemias in adult birds revealed that biting midges were more abundant in nests of females whose blood parasitaemias were experimentally reduced. This finding would be in accordance with these insect vectors attacking preferentially uninfected or less infected hosts to increase their own survival. The abundance of black flies in the population was lower than that of biting midges and increased in nests with later hatching dates. No significant effect of black fly abundance on adult or nestling condition was detected. Blood-sucking flying insects may impose specific, particular selection pressures on their hosts and more research is needed to better understand these host–parasite associations.     

Phylogeny of the infraorder Culicomorpha (Diptera: Nematocera) based on 28S RNA gene sequences

Phylogenetic relationships between the families of the infraorder Culicomorpha were investigated by using partial 28S ribosomal RNA gene sequences. All families traditionally placed in this infraorder were investigated and confirmed as clades. On the other hand, some of the morphological relationships between these families were found to be in disagreement with phylogenies based on molecular characters. Our results did not support the generally accepted division of the Culicomorpha into two superfamilies, the Culicoidea (Culicidae + Corethrellidae + Chaoboridae + Dixidae) and the Chironomoidea (Chironomidae + Ceratopogonidae + Simuliidae + Thaumaleidae). Precisely, if the sister-group relationship between Culicidae, Chaoboridae and Corethrellidae was clearly confirmed, the Dixidae, traditionally considered as closely related to these two families, were not placed close to them on our trees. On the other hand, strong evidence was found for grouping together the Simuliidae and the Thaumaleidae, in spite of the cytological and morphological differences between these two families. The position of the Ceratopogonidae was uncertain, and the Chironomidae appeared as a possible sister group to the rest of Culicomorpha. The phylogenetic positions of the groups characterized by feeding on vertebrate blood or insect haemolymph (the Culicidae, Chaoboridae, Ceratopogonidae and Simuliidae) suggest that haematophagy has appeared at least twice in the evolution of Culicomorpha.     

Bloodsucking dipterans (Diptera: Ceratopogonidae,Culicidae, Simuliidae,Tabanidae) of the Kurgala Peninsula,Leningrad Province

The fauna of bloodsucking dipterans of the Kurgala Peninsula comprises 73 species, 34 of which belong to mosquitoes (Culicidae), 18 to blackflies (Simuliidae), 5 to biting midges (Ceratopogonidae, genus Culicoides), and 16 species to horseflies (Tabanidae). Nine species of the bloodsucking dipterans found on the Kurgala Peninsula are new to Leningrad Province, 6 of them being also recorded for the first time for the neighboring territories of Estonia and southern Finland.     

Bloodsucking dipteran insects (Diptera) attacking humans and animals (the “gnus” complex) in northwestern Russia: I. General characteristics of the fauna

The fauna of bloodsucking Diptera of northwestern Russia comprises 226 species of mosquitoes (Culicidae), biting midges (Ceratopogonidae), black flies (Simuliidae) and horseflies (Tabanidae). In particular, Culicidae include 41 species from 10 subgenera of 5 genera of 2 subfamilies. Simuliidae are represented by 110 species of 23 genera, belonging to 6 tribes of 2 subfamilies; the genus Culicoides of the Ceratopogonidae, by 31 species; and Tabanidae, by 44 species of 7 genera from 2 subfamilies. There is a necessity of elaboration and application of more advanced forms of information storage and field data standardization. In the Zoological Institute, Russian Academy of Sciences, a special database on the bloodsucking insects of Russia is created in the DBMS Access. A list of abundant bloodsucking species of mosquitoes, biting midges, black flies and horseflies is included. A brief synopsis of bibliography of investigations of the bloodsucking dipterans from northwestern Russia is given, provided with a list of more then 190 publication.     

Endophagy of biting midges attacking cavity-nesting birds

Feeding behaviour, host preferences and the spectrum of available hosts determine the role of vectors in pathogen transmission. Feeding preferences of blood-feeding Diptera depend on, among others factors, the willingness of flies to attack their hosts either in the open (exophagy) or in enclosed places (endophagy). As far as ornithophilic blood-feeding Diptera are concerned, the biting midges (Diptera: Ceratopogonidae) and blackflies (Diptera: Simuliidae) are generally considered to be strictly exophagous. We determined which blood-sucking Diptera enter nest cavities and feed on birds by placing sticky foil traps inside artificial nest boxes. A total of 667 females of eight species of biting midges of the genus Culicoides (Latreille, 1809) were captured on traps during 2006-2007, with Culicoides truncorum (Edwards, 1939) being the dominant species. DNA blood analyses of blood-engorged females proved that midges actually fed on birds nesting in the boxes. Three species were identified as endophagous: Culicoides truncorum, Culicoides pictipennis (Staeger, 1839), and Culicoides minutissimus (Zetterstedt, 1855). Our study represents the first evidence that ornithophilic biting midges are endophagous. The fact that we caught no blackflies in the bird boxes supports the exophagy of blackflies. We believe that our findings are important for surveillance programmes focusing on Diptera that transmit various bird pathogens.     

Predator diversity effects cascade across an ecosystem boundary

Food webs in different ecosystems are often connected through spatial resource subsidies. As a result, biodiversity effects in one ecosystem may cascade to adjacent ecosystems. I tested the hypothesis that aquatic predator diversity effects cascade to terrestrial food webs by altering a prey subsidy (biomass and trophic structure of emerging aquatic insects) entering terrestrial food webs, in turn altering the distribution of a terrestrial consumer (spider) that feeds on emerging aquatic insects. Fish presence, but not diversity, altered the trophic structure of emerging aquatic insects by strongly reducing the biomass of emerging predators (dragonflies) relative to non‐feeding taxa (chironomid midges). Fish diversity reduced emerging insect biomass through enhanced effects on the most common prey taxa: predatory dragonflies Pantala flavescens and non‐feeding chironomids. Terrestrial spiders (Tetragnathidae) primarily captured emerging chironomids, which were reduced in the high richness (3 spp.) treatment relative to the 1 and 2 species treatments. As a result, terrestrial spider abundance was lower above pools with high fish richness (3 species) than pools with 1 and 2 species. Synergistic predation effects were mostly limited to the high richness treatment, in which fish occupied each level of vertical microhabitat in the water‐column (benthic, middle, surface). This study demonstrates that predator diversity effects are not limited to the habitat of the predator, but can propagate to adjacent ecosystems, and demonstrates the utility of using simple predator functional traits (foraging domain) to more accurately predict the direction of predator diversity effects.     

Parasite effects on host’s trophic and isotopic niches

Wild animals are usually infected with parasites that can alter their hosts’ trophic niches in food webs as can be seen from stable isotope analyses of infected versus uninfected individuals. The mechanisms influencing these effects of parasites on host isotopic values are not fully understood. Here, we develop a conceptual model to describe how the alteration of the resource intake or the internal resource use of hosts by parasites can lead to differences of trophic and isotopic niches of infected versus uninfected individuals and ultimately alter resource flows through food webs. We therefore highlight that stable isotope studies inferring trophic positions of wild organisms in food webs would benefit from routine identification of their infection status.     

The influence of environmental management and animal shelters in vector control of Culicoides (Diptera,Ceratopogonidae) in northeastern Brazil

We investigated whether biting midges in peridomestic environments are affected by environmental management practices and the presence of domestic animals. We used CDC light traps to collect midges in 112 residences across 24 locations along tourism routes of Maranhão, Brazil. The collection areas were characterized as follows: i) peridomestic area with domestic animals and without management (dirty); ii) peridomestic with domestic animals and management (clean); iii) peridomestic without animals and with management (clean); iv) peridomestic without animals and without management (dirty). The first two treatments had higher biting midge species richness and abundance, respectively. Generalized linear models indicated a positive correlation between the presence of domestic animals and midge abundance, with an approximate four‐fold increase in Culicoides (Diptera: Ceratopogonidae) abundance in peridomestic areas with animals. The same model showed that domestic animals have no influence on richness. Environmental management does not appear to influence species richness or abundance of biting midges.     

吸血蠓及其传播的疾病

吸血蠓广泛分布世界各地,其危害不仅在于刺吸人畜等动物血液,而且是多种疾病的传播媒介。了解吸血蠓及其传播的疾病,对有效预防和控制吸血蠓及蠓媒病具有重要意义。     

Parasite-host associations and life cycles of spring-living water mites (Hydrachnidia, Acari) from Luxembourg

Larval water mites are parasites of various insect species. The main aim of the present study was to analyse the host range of spring dwelling water mites. The investigation focuses on seven spring sites in Luxembourg. Some 24 water mite species were recorded either from the benthos or as parasites attached to flying insects captured in emergence traps. For 20 mite species 35 host species from four Nematocera (Diptera) families were recorded. About 80% of the host species and over 90% of the host individuals were Chironomidae, the others were Limoniidae, Dixidae and Simuliidae. For all water mite species recorded we present the observed host spectrum and/or potential hosts as well as the intensity of parasitism and the phenology of the mites. For 10 mite species the hosts were previously unknown. For another ten species the known host spectrum can be confirmed and extended. The host spectrum ranged from one host species (e.g. for Sperchon insignis) to at least 10 host species (for Sperchon thienemanni, Ljania bipapillata), but the effective host range could not be definitively estimated due to the lack of corresponding data. The hypothesised host preference of the water mites, of which most are strictly confined to spring habitats, for similarly spring-preferring hosts could not be proven. The mean intensity of parasitism was highest for Thyas palustris (10.8 larvae/host) and lowest for Sperchon insignis and Hygrobates norvegicus (1.2 larvae per host for each). The hydryphantid mite Thyas palustris occurred at maximal intensity (41 larvae per host) and the two abdominal parasites Ljania bipapillata and Arrenurus fontinalis showed higher mean intensities than the thoracic parasites did. Larval water mites parasitising chironomids did not exhibit a preference for host sex. The phenology of the larval mite species was varied, some species were only present in samples early in the year and others exclusively in the summer. Another species showed two peaks of occurrence, springtime/early summer and late summer/autumn. In conclusion, the water mite larvae in the studied springs showed differences in host spectra and phenology but there are no clear evidences in both for host partitioning. Maybe, the relative low species diversity of water mites in individual springs and the low inter-specific competition for suitable hosts in combination with the high host abundances and species richness makes springs such favourable habitats for the mites.     

The role of trout in stream food webs: integrating evidence from field surveys and experiments

1. We evaluated the effects of brown trout on boreal stream food webs using field surveys and enclosure/exclosure experiments. Experimental results were related to prey preference of uncaged trout in the same stream, as well as to a survey of macroinvertebrate densities in streams with vs. without trout. Finally, we assessed the generality of our findings by examining salmonid predation on three groups of macroinvertebrate prey (chironomid midges, epibenthic grazers, invertebrate predators) in a meta-analysis. 2. In a preliminary experiment, invertebrate predators showed a strong negative response to trout, whereas chironomids benefited from trout presence. In the main experiment, trout impact increased with prey size. Trout had the strongest effect on invertebrate predators and cased caddis larvae, whereas Baetis mayfly and chironomid larvae were unaffected. Trout impact on the largest prey seemed mainly consumptive, because prey emigration rates were low and independent of fish presence. Despite strong effects on macroinvertebrates, trout did not induce a trophic cascade on periphyton. Uncaged trout showed a strong preference for the largest prey items (predatory invertebrates and aerial prey), whereas Baetis mayflies and chironomids were avoided by trout. 3. Densities of invertebrate predators were significantly higher in troutless streams. Baetis mayflies also were less abundant in trout streams, whereas densities of chironomids were positively, although non-significantly, related to trout presence. Meta-analysis showed a strong negative impact of trout on invertebrate predators, a negative but variable impact on mobile grazers (mainly mayfly larvae) and a slightly positive impact on chironomid larvae. 4. Being size-selective predators, salmonid fishes have a strong impact on the largest prey types available, and this effect spans several domains of scale. Discrepancies between our experimental findings and those from the field survey and meta-analysis show, however, that for most lotic prey, small-scale experiments do not reflect fish impact reliably at stream-wide scales. 5. Our findings suggest that small-scale experiments will be useful only if the experimental results are evaluated carefully against natural history information about the experimental system and interacting species across a wide array of spatial scales.     

Toward development of neem-based repellents against the Scottish Highland biting midge Culicoides impunctatus

Oil of neem, from the tree Azadirachta indica A. Juss (Meliaceae), was evaluated for repellent and antifeedant activity against Culicoides biting midges (Diptera: Ceratopogonidae), by three complementary methods with serial dilutions. Electroantennograms revealed the sensitivity of Culicoides nubeculosus (Meigen) females to neem > or = 0.10%. Culicoides impunctatus Goetghebuer females were repelled by > or = 1% in a Y-tube olfactometer, Using a membrane feeder for wild-caught parous females of C. impunctatus, the proportion blood-feeding was significantly reduced by topical applications of neem oil > or = 0.10% concentrations, with blood-feeding completely prevented by > or =1%. On the basis of these response data, we developed 2% neem-based formulations for personal protection against biting midges.     

Development and evaluation of real‐time PCR assays for bloodmeal identification in Culicoides midges

Culicoides (Diptera: Ceratopogonidae) midges are the biological vectors of a number of arboviruses of veterinary importance. However, knowledge relating to the basic biology of some species, including their host‐feeding preferences, is limited. Identification of host‐feeding preferences in haematophagous insects can help to elucidate the transmission dynamics of the arboviruses they may transmit. In this study, a series of semi‐quantitative real‐time polymerase chain reaction (qPCR) assays to identify the vertebrate host sources of bloodmeals of Culicoides midges was developed. Two pan‐reactive species group and seven species‐specific qPCR assays were developed and evaluated. The assays are quick to perform and less expensive than nucleic acid sequencing of bloodmeals. Using these assays, it was possible to rapidly test nearly 700 blood‐fed midges of various species from several geographic locations in Australia.     

Spatial stratification of host-seeking Diptera in boreal forests of northern Europe

The stratification of haematophagous Diptera was assessed in two boreal forests in northern Sweden by placing traps baited with carbon dioxide at 1.5 m, 5.0 m and 10.0 m above the ground. More than 40 000 specimens were captured, including 617 biting midges (Ceratopogonidae), 4029 mosquitoes (Culicidae) and 36 092 black flies (Simuliidae). Catches at the various trap heights reflected the general vertical distribution of the preferred hosts, with mammalophilic flies predominating (68.6%) in catches at 1.5 m and ornithophilic flies (42.4%) in catches at 10.0 m; however, most flies that use host birds at ground level were caught in the lowest traps (e.g. 85.1% of Simulium annulus were collected at 1.5 m). Within-species variation in vertical patterns between forests suggests plasticity in responses to environmental factors such as vegetative structure.