The structure of carrion fly communities: the size and the type of carrion

Species composition and abundance relations of flies attracted to and bred from different sizes (20-100 g) and types of carrion (small mammal, cow liver, bird, and fish) were studied experimentally in natural breeding conditions in South Finland. Large pieces of carrion did not attract significantly more individuals or species than did small ones, but there was a positive correlation between size of carrion and numbers of flies bred, apparently because of competition. Altogether 10 species emerged from 50 cultures, and on average 2.78 ± 1.22 (SD) species emerged from one culture. The number of co-occurrences among the emerging flies indicated random colonization. Variation in species composition between like pieces of carrion was not less than variation between carcasses of different size or type; hence, size and type of carrion are not important determinants of community structure within the size and type ranges used.
Lucilia illustris (Meig.) was the predominant species, comprising 50% of flies trapped and 85% of flies bred. The difference indicates changing species composition in the community. Two sets of cultures were left open for egg-laying for 2 and 7 d. Competition was less Intensive in the former cultures, which produced 4.0 individuals per gram of carrion, contrasting with only 1.4 individuals per gram in the latter cultures. Competition delayed development in all species, but least in L. illustris , which suggests that fast developing species are at a competitive advantage. In agreement with this, abundance was positively correlated with the rate of development.     

On the Specific Features of Pupal Development of Horseflies (Diptera,Tabanidae) in Northwestern Russia

Entomological Review - Specific features of pupal development of horseflies were experimentally studied by the example of species of the family Tabanidae in Pskov Province. In particular, the...     

Macrogeographic population structure of the tsetse fly, Glossina pallidipes (Diptera: Glossinidae)

Tsetse flies are confined to sub-Saharan Africa where they occupy discontinuous habitats. In anticipation of area-wide control programmes, estimates of gene flow among tsetse populations are necessary. Genetic diversities were partitioned at eight microsatellite loci and five mitochondrial loci in 21 Glossina pallidipes Austin populations. At microsatellite loci, Nei's unbiased gene diversity averaged over loci was 0.659 and the total number of alleles was 214, only four of which were shared among all populations. The mean number of alleles per locus was 26.8. Random mating was observed within but not among populations (fixation index FST=0.18) and 81% of the genetic variance was within populations. Thirty-nine mitochondrial variants were detected. Mitochondrial diversities in populations varied from 0 to 0.85 and averaged 0.42, and FST=0.51. High levels of genetic differentiation were characteristic, extending even to subpopulations separated by tens and hundreds of kilometres, and indicating low rates of gene flow.     

The oldest bee fly in the French Paleocene (Diptera: Bombyliidae)

Paleolomatia menatensis gen. and sp. n., oldest Bombyliidae sensu stricto, is described from the Paleocene of Menat (France). The new genus, based on the wing venation, is attributed to the rather ‘derived’ subfamily Lomatiinae, strongly supporting a Late Cretaceous age for the diversification of the pollinator bee flies, in relation with the floristic changes and the angiosperm radiation that occurred at the same time.     

The character of soldier fly distribution (Diptera,Stratiomyidae) in Eastern Europe

A total of 81 soldier fly species (Diptera, Stratiomyidae) belonging to 4 subfamilies occur in Eastern Europe (the East European Plain and Ciscaucasia). This fauna is compared to that of Western Europe and the chorological analysis of species found in Eastern Europe is given. According to the type of the geographic range, 13 species-groups and several subgroups were distinguished. Northern range borders in Eastern Europe and eastern borders of distribution of some species are discussed. The ratio between different subfamilies in the number of species in different parts of the territory under study is demonstrated.     

Salinity tolerance of stable fly (Diptera: Muscidae)

Effects of salinity on the survival, growth, and development of stable fly, Stomoxys calcitrans (L.), were investigated in the laboratory. Larvae failed to develop to pupation when reared in media containing a salinity of 40 parts per thousand (ppt) sodium chloride (NaCl). Maximum salinity supporting larval development equaled the salinity of seawater (34 ppt); the larval LC90 was 24.2 ppt. Deleterious effects of high salinity decreased as larvae matured. Six-day-old larvae reared at a salinity of 34 ppt weighed 79% less than controls, compared with a 36% difference in 9-d-old larvae; by pupation, the difference was only 24%. Salinity did not influence the duration of larval, pupal, or adult stages. Survival of pupae was unimpaired despite a slight increase in number of pupal deformities, and normal adults emerged. Eggs were highly tolerant to saline. They hatched at salinity concentrations lethal to larvae; greater than 50% hatch occurred even when eggs were maintained at 80 ppt NaCl. Sensitivity of larvae to salinities close to that of seawater might be important for control of stable flies inhabiting marine areas.     

Mating time of the West Indian fruit fly Anastrepha obliqua (Macquart) (Diptera: Tephritidae) under laboratory conditions

Allochronic reproductive isolation seems to be an important factor in speciation processes in Tephritidae since specific mating times are a widespread feature of its species. The timing of matings of the West Indian fruit fly, Anastrepha obliqua (Macquart) was investigated through group-focal observations, during ten days, under laboratory conditions. The number of observed matings and males exhibiting calling behavior varied significantly according to time of day. Sexual activities seemed to be concentrated in the afternoon period, with the male calling behavior reaching a peak between 3:30p.m. and 4:30p.m., and mating occurred most frequently from 2:00 p.m. to 4:30 p.m.     

Gut bacterial communities in the Mediterranean fruit fly (Ceratitis capitata) and their impact on host longevity

Fruit flies (Diptera: Tephritidae) harbor stable bacterial communities in their digestive system, composed mainly of members of the Enterobacteriaceae. However, the Enterobacteriaceae are not the sole community in this habitat. We examined the hypothesis that Pseudomonas spp. form a cryptic community in the gut of Ceratitis capitata, the Mediterranean fruit fly (‘medfly’). Suicide polymerase restriction PCR (SuPER PCR), a novel culture-independent technique, revealed that Pseudomonas spp. form minor, common and stable communities within the medfly's gut. These include P. aeruginosa, a known pathogen of arthropods. Experimental inoculations with high levels of P. aeruginosa reduced the medfly's longevity while inoculations with members of the Enterobacteriaceae extended the fly's life.Accordingly, we suggest that in addition to their possible contribution to the fly's nitrogen and carbon metabolism, development and copulatory success (as shown in previous studies), the Enterobacteriaceae community within the medfly's gut may also have an indirect contribution to host fitness by preventing the establishment or proliferation of pathogenic bacteria.     

Beauveria bassiana as a pathogen of the Mexican fruit fly (Diptera: Tephritidae) under laboratory conditions

Bioassays were carried out under controlled conditions (27 +/- 2 degrees C, 80 +/- 5% RH, and a photoperiod of 12:12 [L:D] h) to evaluate the effect of eight strains of the entomopathogenic fungus Beauveria bassiana upon larvae, pupae, and adult females of the Mexican fruit fly, Anastrepha ludens (Loew). Mortality of the immature stages was low, 2-8% in larvae and 0% in pupae. However, very high levels of mortality were obtained for adult flies, with values of 100, 98, and 98% for the strains Bb16, Bb24, and Bb26, respectively. LC50 values for these three strains ranged from 3.12 x 10(6) to 9.07 x 10(6) conidia/ml. Lethal time 50 (LT50) was 2.8, 3.7, and 4.2 d for Bb16, Bb26, and Bb24 strains, respectively, with an average LT50 of 4.4 d across all strains. The fungal mycelium emerged through the soft parts of the exoskeleton, such as the wing bases, mouth, intersegmental regions of the legs, and membranous regions of the abdomen, coxae, and neck. Maximum percentage sporulation ranged from 66.4 to 74.7% for the three most virulent strains.     

Innervation and structure of mouth part sensilla in females of the black fly Simulium venustum (Diptera: Simuliidae)

Associated with the mouth parts of female Simulium venustum are 13 morphologic types of sensilla: four on the labium, seven on the labrum, one in the cibarium, and one on the genal process to which the mandibles articulate. Seven types are probably sensitive only to mechanicla cues and three only to chemical ones, whereas the other three probably function in both modes. These sensilla likely monitor feeding-associated chemical features of blood, sugar, and water and mechanical cues generated by the physical acts of ingestion. Each S. venustum female has approximately 450 chemosensitive and 230 mechanosensitive neurons in the mouthpart-associated sensilla. Both the total number of chemosensory neurons and the ratio of chemosensory to mechanosensory neurons in S. venustum are intermediate between those for blow flies, which feed on a wide variety of foodstuffs, and tsetse flies, exclusive blood-feeders. These differences may be related to whether determination of acceptability of a potential food source occurs at the site of feeding and is dependent upon simultaneous sensitivity to many chemical cues, as in blow flies, or is the result of a complex stimulus chain composed of all host-location steps and culminating with the detection of but a few phagostimulants in the food itself, as in blood-feeders.     

Comparison of the efficacy of different food attractants and their concentration for melon fly (Diptera: Tephritidae)

The relative attractiveness of six commercially available protein hydrolysates and the influence of their concentration were evaluated in field cages by a release-capture method of lab-reared melon fly adults, Bactrocera cucurbitae (Coquillett). Buminal, Corn Steepwater, Hym-Lure, Pinnacle, Nulure, and SolBait were tested for both sexes of the melon fly. The tested products exhibited clear differences in attractiveness. SolBait was the most effective protein hydrolysate. Pinnacle and Corn Steepwater also gave promising results. A general tendency for an increase in effectiveness with increasing concentration within the range 0.5 to 10% was shown. This study will allow pest control practitioners to choose more effective attractants for use in bait sprays to control the melon fly thus reducing the intensive use of insecticides currently practiced in Reunion island and enabling the development of Integrated pest management (IPM) methods for cucurbit crops.     

Sperm structure of Limoniidae and their phylogenetic relationship with Tipulidae (Diptera, Nematocera)

The sperm ultrastructure of a few species of Limoniidae (Limonia nigropunctata; L. nubeculosa; Chionea n. sp.; C. alpina; C. lutescens) was studied. The two species of Limonia have a monolayered acrosome with crystallized material, a three-lobed nucleus in cross section, a ring of centriole adjunct material and a flagellum which consists of a 9+9+1 axoneme and a single mitochondrial derivative. The central axonemal tubule is provided with 15 protofilaments in its tubular wall, while the accessory tubules have 13 protofilaments and are flanked by the electron-dense intertubular material. The three species of Chionea share a monolayered acrosome, a nucleus with two longitudinal grooves, a centriole adjunct material which surrounds the centriole and the initial part of the axoneme. The axoneme is of conventional type, with 9+9+2 microtubular pattern, with accessory tubules provided with 13 protofilaments and intertubular material. However, in C. lutescens the accessory tubules start with 15 protofilaments and transform into a tubule with 13 protofilaments. These data are discussed in the light of the phylogenetic relationship between Limoniidae and Tipulidae. For this purpose, the sperm ultrastructure of Nephrotoma appendiculata was also considered comparatively.     

Insecticide resistance and cross-resistance in the house fly (Diptera: Muscidae)

A house fly strain, ALHF, was collected from a poultry farm in Alabama after a control failure with permethrin, and further selected in the laboratory with permethrin for five generations. The level of resistance to permethrin in ALHF was increased rapidly from an initial 260-fold to 1,800-fold after selection. Incomplete suppression of permethrin resistance by piperonyl butoxide (PBO) and S,S,S,-tributylphosphorotrithioate (DEF) reveals that P450 monooxygenase- and hydrolase-mediated detoxication, and one or more additional mechanisms are involved in resistance to permethrin. The ALHF strain showed a great ability to develop resistance or cross-resistance to different insecticides within and outside the pyrethroid group including some relatively new insecticides. Resistance to beta-cypermethrin, cypermethrin, deltamethrin, and propoxur (2,400-4,200-, 10,000-, and > 290-fold, respectively, compared with a susceptible strain, aabys) in ALHF house flies was partially or mostly suppressed by PBO and DEF, indicating that P450 monooxygenases and hydrolases are involved in resistance to these insecticides. Partial reduction in resistance with PBO and DEF implies that multiresistance mechanisms are responsible for resistance. Fifteen- and more than fourfold resistance and cross-resistance to chlorpyrifos and imidacloprid, respectively, were not effected by PBO or DEF, indicating that P450 monooxygenases and hydrolases are not involved in resistance to these two insecticides. Forty-nine-fold cross-resistance to fipronil was mostly suppressed by PBO and DEF, revealing that monooxygenases are a major mechanism of cross-resistance to fipronil. Multiresistance mechanisms in the ALHF house fly strain, however, do not confer cross-resistance to spinosad, a novel insecticide derived from the bacterium Saccharopolyspora spinosa. Thus, we propose that spinosad be used as a potential insecticide against house fly pests, especially resistant flies.     

Horn fly (Diptera: Muscidae) insecticide resistance in Kentucky and Arkansas

The effect of previous insecticide use patterns for horn fly control on the susceptibility spectrum of horn fly (Haematobia irritans [L.]) populations from Kentucky and Arkansas is described. Populations of horn flies from both states were tested with three pyrethroids (cyhalothrin, cypermethrin, and permethrin), three organophosphates (diazinon, pirimiphos methyl, and tetrachlorvinphos), and a chlorinated hydrocarbon (methoxychlor). Dose-mortality data indicated insecticide resistance in Arkansas and Kentucky. Two permethrin-resistant horn fly populations in Kentucky that did not have a history of exposure to methoxychlor were cross-resistant to this chlorinated hydrocarbon. Horn fly populations from both states with a history of at least three consecutive years of exposure to various pyrethroid ear tags were subsequently exposed to cattle tagged with cyhalothrin-impregnated ear tags for 15-16 wk. Such exposure resulted in a decrease in susceptibility to this pyrethroid (ranging from approximately 30 to greater than 100-fold) when compared with levels before treatment. Horn fly populations from Arkansas resistant to cyhalothrin (as a result of exposure to cyhalothrin ear tags) were cross-resistant to pirimiphos methyl. Seasonal exposure of an Arkansas and Kentucky horn fly population to cattle with ear tags impregnated with pirimiphos methyl resulted in a significant decrease in susceptibility to this organophosphate.     

The structure of the fauna and life cycles of black flies (Diptera,Simuliidae) in streams of the forest-steppe in central Russia

The paper deals with the species composition, life cycles, structure of the fauna, and biodiversity of black flies (Diptera, Simuliidae) in different types of streams in the central Russian forest-steppe. Complexes of black flies in different types of streams are rather similar but faunas differ in the dominance structure.     

Intra- and interspecific competition and host race formation in the apple maggot fly,Rhagoletis pomonella (Diptera: Tephritidae)

Intra- and interspecific resource competition are potentially important factors affecting host plant use by phytophagous insects. In particular, escape from competitors could mediate a successful host shift by compensating for decreased feeding performance on a new plant. Here, we examine the question of host plant-dependent competition for apple (Malus pumila)- and hawthorn (Crataegus mollis)-infesting larvae of the apple maggot fly, Rhagoletis pomonella (Diptera: Tephritidae) at a field site near Grant, Michigan, USA. Interspecific competition from tortricid (Cydia pomonella, Grapholita prunivora, and Grapholita packardi) and agonoxenid (subfamily Blastodacninae) caterpillars and a curculionid weevil (Conotrachelus crataegi) was much stronger for R. pomonella larvae infesting the ancestral host hawthorn than the derived host apple. Egg to pupal survivorship was estimated as 52.8% for fly larvae infesting hawthorn fruit without caterpillars and weevils compared to only 27.3% for larvae in harthorns with interspecific insects. Survivorship was essentially the same between fly larvae infesting apples in the presence (44.8%) or absence (42.6%) of interspecific insects. Intraspecific competition among maggots was also stronger in hawthorns than apples. The order or time that a larva exited a hawthorn fruit was a significant determinant of its pupal mass, with earlier emerging larvae being heavier than later emerging larvae. This was not the case for larvae in apples, as the order or time that a larva exited an apple fruit had relatively little influence on its pupal mass. Our findings suggest that decreased performance related to host plant chemistry/nutrition may restrict host range expansion and race formation in R. pomonella to those plants where biotic/ecological factors (i.e. escape from competitors and parasitoids) adequately balance the survivorship equation. This balance permits stable fly populations to persist on novel plants, setting the stage for the evolution of host specialization under certain mitigating conditions (e.g. when mating is host specific and host-associated fitness trade-offs exist).     

Cyclorrhaphous Dipterans (Diptera Cyclorrhapha) inhabiting bird nests in Russia and Ukraine

A synopsis of 20 species of Diptera Cyclorrhapha from 10 families occurring in bird nests is presented. Some species were found for the first time in bird nests. The roles of each fly species in the bird nest consortia, the mode of larval life, associations with nestlings or nest substrate are discussed. Most flies are widely distributed, the possible explanations for which are proposed.