First survey of seasonal abundance and daily activity of Stomoxys spp. (Diptera: Muscidae) in Kamphaengsaen Campus, Nakornpathom province, Thailand

The seasonal changes and the daily activity of Stomoxyine species (Diptera: Muscidae) were examined, using Vavoua traps, in a dairy and a beef cattle farm in Nakhonpathom province, Thailand during July 2004 to June 2005. Over this period, Stomoxys calcitrans was the most commonly trapped species, followed by S. sitiens and S. indica. For the later species, this is the first report of its presence in Thailand. A total of 80 % of flies were captured during the rainy season from May to October and 20 % during the dry season from November to April. No major difference of fly density was observed between the dairy and the beef cattle farm. The activity pattern of S. calcitrans was diurnal with a peak between 08:00 am to 10:00 am and another less marked one in the afternoon. The activity pattern of S. sitiens and S. indica was mainly crepuscular with 2 peaks, early in the morning (06:00 a.m.) and late in the afternoon (6:00 p.m.). Those species are important pests of livestock in Thailand, where they are known as a mechanical vector of trypanosomes. A better knowledge of their ecology is a prerequisite for more efficient control measures.     

Attraction of Stomoxys sp. to various fruits and flowers in Mali

The attraction of three Stomoxys species to 26 fruits and 26 flowers of different plant species was investigated in two different sites in Mali during 2008. Stomoxys niger bilineatus Grunberg (Diptera: Muscidae) was attracted to a wider spectrum of species, significantly attracted by four fruits and eight flowers compared with control traps, whereas S. sitiens Rondani (Diptera: Muscidae) was attracted to six fruits and seven flowers of different plants, and S. calcitrans L. (Diptera: Muscidae) was only attracted to one fruit and three flowers. Cold anthrone assays showed a significantly higher prevalence of sugar feeding amongst all three species at the lagoon site than at the site near Mopti. The rhythm of activity study shows temporally separated blood- and sugar-feeding periods for S. niger bilineatus and S. sitiens, but not for S. calcitrans. A comparison between blood and sugar feeding throughout the day shows that sugar feeding activity is as frequent as blood feeding activity. Because not much is known about the preferred sugar sources for Stomoxys species in their natural habitats, the present study provides valuable information regarding the attraction capability of several plants with possible future implication for Stomoxys control strategies.     

Ecology of Stomoxys flies (Diptera: Muscidae) in Gabon. I. First survey in different ecological areas

The stomoxyine flies are hematophagous diptera and potential vectors of various pathogenic agents. Like those of the Afrotropical Region, the stomoxyine flies of Gabon remain nearly unknown. For these reasons, an entomological survey was conducted in a transverse way in eight localities representative of the various ecological zones of Gabon. The survey was based on the use of Vavoua traps. Various environmental factors able to influence the captures were noticed and included into a canonical correspondence analysis. In total, 15,966 Stomoxys spp., belonging to seven species or subspecies, were captured. The apparent densities (DAP) expressed as the number of flies per trap and per day, were highest in Franceville (41), Bakoumba (40), Makokou (25) and Mouila (21). The most abundant species were S. n niger (33.4%), S. transvittatus (33%), then S. calcitrans (17%). The principal factors that could explain the variability of the captures were the degree of anthropisation, the botanical facies (savanna or forest), the presence of wild and domestic fauna and the nature of the vegetal cover of the ground. S. calcitrans, S. niger niger were abundant in the areas where human presence was manifest. S. xanthomelas was present in forest belts. S. transvittatus, S. omega, S. inornatus were ubiquitous species. S. niger bilineatus was found in savannas areas.     

Circadian activity pattern in the stable fly, Stomoxys calcitrans

Abstract. Activity rhythms of Stomoxys calcitrans (L.) were assessed under constant conditions using actographs.In LD 12:12 h, activity was almost completely diurnal, had a 24 h period, and peaked 4 h after lights-on.In constant darkness, activity peaked in the early afternoon and the period of the rhythm was c. 26 h, indicating a circadian pacemaker.A delay in feeding shortened the free-running period in constant dark to c. 24 h.In constant light, flies were arrhythmic.Starvation also affected activity, with 24- and 48-h starved flies being as much as 20 times more active than recently fed flies.     

Sensory and behavioural responses of the stable fly Stomoxys calcitrans to rumen volatiles

Analysis of volatiles from rumen digesta by gas chromatography linked antennogram recordings from Stomoxys calcitrans (L) (Diptera: Muscidae) antennal receptor cells revealed about 30 electrophysiologically active constituents, the most important of which is dimethyl trisulphide with a sensory threshold in the femtogram range. The behavioural responses of S. calcitrans to five chemostimulants (dimethyl trisulphide, butanoic acid, p-cresol, oct-1-en-3-ol and skatole) were tested in a wind tunnel where activation and attraction of hungry flies to rumen volatiles were recorded. Dimethyl trisulphide, butanoic acid and p-cresol were found to attract S. calcitrans. This sensitivity to rumen volatile constituents, that also occur in animal wastes used for oviposition by Stomoxys spp., as well as in flowers used by stable flies as sources of nectar is discussed in the context of the behavioural ecology of these flies.     

Effect of host behaviour on host preference in Stomoxys calcitrans

Field observations suggest that, in the U.K., cattle are the preferred host of Stomoxys calcitrans (L.), followed by horses. Differences were observed in the numbers of flies feeding on individual animals both in the field and under controlled conditions. Analysis of the behaviour of four Friesian calves under attack from S. calcitrans in controlled conditions revealed that the differences in the levels of attack between individual hosts are dependent on the reactions of the host when under attack. Those hosts which respond vigorously by tail flicks, foot stamps and head-swings suffer less from attack by S. calcitrans than their more placid contemporaries.     

Retention and attempted mechanical transmission of Ehrlichia risticii by Stomoxys calcitrans

Abstract. The ability of adult Stomoxys calcitrans (L.) (Diptera: Muscidae) to retain viable Ehrlichia risticii (Rickettsiaceae), the aetiologic agent of Potomac horse fever (PHF), and mechanically transmit the pathogen from citrated bovine blood artificially infected with E.risticii to susceptible mice was studied. Viable E. risticii were found in the digestive tract of S.calcitrans 3h after the flies had engorged to repletion on infected blood; however, no E. risticii were detected in flies ≥2 days after feeding. Subsequently, groups of S.calcitrans were fed for 20 s on infected blood, then fed to repletion on mice 30, 60,130, 180 or 220 min after having feeding interrupted. Mice displayed no clinical signs of PHF and did not produce anti- E. risticii antibodies when assayed 30 days after S. calcitrans had fed. Although S.calcitrans were able to harbour viable E.risticii for at least 3h, transmission of the disease agent to susceptible mice during interrupted feeding was not demonstrated under these experimental conditions.     

Observations on the mite fauna associated with adult Stomoxys calcitmns in the U.K.

Abstract. Adult females of the blood-sucking muscid Stomoxys calcitrans sampled between June and September 1993 from a cattle farm ( n = 839) and from a pig farm ( n = 542) in North-West England were examined for mites. Twelve species of mites from ten families and three orders were identified as follows. In the Prostigmata, Eryenetes sp., Family Ereynetidae and Pediculaster mesembrinae , Family Pygmephoridae. In the Astigmata, Procalvolia zacheri Family Saproglyphidae, Acarusfarris , Family Acaridae, Bonomoia sphaerocerae and Myianoetus sp., Family Anoetidae. In the Mesostigmata, Macrocheles muscaedomesticae and Macrocheles subbadius Family Macrochelidae, Digamasellus sp., Family Digamasellidae, Halolaelaps sp., Family Halolaelapidae. Prodinychus sp., Family Uropodoidea and Thinoseius sp., Family Eviphididae. Mean infestation rates at the two sites (all mite species) for the entire sampling period were 31.6 ± 13.9% and 19.8 ± 3.6% respectively. 51 % of synbovine flies sampled in July were infested with mites. Mean numbers of flies infested in August at both farms were significantly lower compared to other months. The presence of tritonymphs of Ereynetes sp. on S.calcitrans demonstrates for the first time that this life cycle stage is naturally associated with insects in the field.
All mites were recovered from the ventral thorax and abdomen, and two or more species commonly infested individual flies. Associations of mites with their dipteran hosts are described and discussed.     

Epithelial innate immunity. A novel antimicrobial peptide with antiparasitic activity in the blood-sucking insect Stomoxys calcitrans

The gut epithelium is an essential interface in insects that transmit parasites. We investigated the role that local innate immunity might have on vector competence, taking Stomoxys calcitrans as a model. S. calcitrans is sympatric with tsetse flies, feeds on many of the same vertebrate hosts, and is thus regularly exposed to the trypanosomes that cause African sleeping sickness and nagana. Despite this, S. calcitrans is not a cyclical vector of these trypanosomes. Trypanosomes develop exclusively in the lumen of digestive organs, and so epithelial immune mechanisms, and in particular antimicrobial peptides (AMPs), may be the prime determinants of the fate of an infection. To investigate why S. calcitrans is not a cyclical vector of trypanosomes, we have looked in its midgut for AMPs with trypanolytic activity. We have identified a new AMP of 42 amino acids, which we named stomoxyn, constitutively expressed and secreted exclusively in the anterior midgut of S. calcitrans. It displays an amphipathic helical structure and exhibits a broad activity spectrum affecting the growth of microorganisms. Interestingly, this AMP exhibits trypanolytic activity to Trypanosoma brucei rhodesiense. We argue that stomoxyn may help to explain why S. calcitrans is not a vector of trypanosomes causing African sleeping sickness and nagana.     

Potential impacts of climate change on stable flies, investigated along an altitudinal gradient

Adult populations of stable flies were sampled along an altitudinal transect in Reunion Island to determine whether higher temperatures were associated with: (a) higher numbers of flies; (b) a longer season of infestation, and/or (c) different responses to warming in the cosmopolitan Stomoxys calcitrans (L) and the tropical Stomoxys niger niger Macquart (Diptera: Muscidae). Flies of both species were trapped at seven farms situated at four altitudes (100-1600 m a.s.l.) over a 90-week period. For both species, there were no relationships between the maximum or mean fly abundance and altitude. Only minimum abundance in winter was significantly higher at lower altitudes. Maximum and mean abundances differed significantly between nearby farms under similar climatic conditions. Seasonal fluctuations in fly abundance changed along the gradient. At lower altitudes, population growth started earlier after the winter but abundance declined earlier in summer, which resulted in a shift of the season of infestation. Seasonal fluctuations of both species were strongly related to climate variables at high altitude, mainly temperature. However, climate variables explained a decreasing proportion of the variations in abundance at lower altitudes. Stomoxys calcitrans was the most abundant species overall, but the proportion of S. n. niger increased significantly at lower altitudes and this species became predominant at 100 m a.s.l. It is concluded that stable fly infestations are unlikely to worsen in response to global warming. Maximum abundance is limited by local factors, possibly larval resources, which suggests that adequate husbandry practices could override the impact of climate change. Because S. n. niger tends to be the predominant pest at elevated temperatures, it is recommended that this species should not be introduced in areas where climate is changing.     

Chemostimuli implicated in selection of oviposition substrates by the stable fly Stomoxys calcitrans

Horse and cow dung were tested as substrates for oviposition by the stable fly Stomoxys calcitrans (L) (Diptera: Muscidae) in laboratory cages. Odour alone from either horse or cow dung was sufficient to attract flies for oviposition. This was confirmed in wind tunnel experiments, where both horse and cow dung were shown to attract gravid stable flies. However, when S. calcitrans was offered a choice between these two oviposition substrates, flies always chose horse dung over cow dung, both when allowed to contact the substrates and when relying on dung odour alone. Analyses of volatile compounds emanating from horse and cow dung by gas chromatography linked antennogram recordings from S. calcitrans antennae revealed no differences in the chemostimuli released from the two substrates. The predominant chemostimulant compounds in both substrates were carboxylic acids (butanoic acid), alcohols (oct-1-en-3-ol), aldehydes (decanal), ketones (octan-3-one), phenols (p-cresol), indoles (skatole), terpenes (beta-caryophyllene) and sulphides (dimethyl trisulphide). Higher levels (20-40 p.p.m.) of carbon dioxide were recorded over horse dung compared with cow dung, a factor that may contribute to the preference exhibited by S. calcitrans for this substrate for oviposition.     

Twenty-three new microsatellite loci in the stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae)

The stable fly, Stomoxys calcitrans (L.), is a significant pest of cattle. Twenty-three microsatellite markers were isolated from a repeat-enriched genomic library of S. calcitrans. We characterized variation at these markers and found that 17 loci were polymorphic in two fly populations from Florida. Two to nine alleles were observed among the variable microsatellite loci and expected heterozygosities ranged from 0.03704 to 0.85115. These markers will be useful for characterizing population genetic differentiation and for tracking the migration patterns of stable flies in the USA and worldwide.     

The absolute number of the stable fly (Stomoxys calcitrans) in the buildings of dairy farms]

In order to estimate the absolute number of Stomoxys calcitrans subpopulation in housings of a dairy farm the capture-mark-recapture method has been used. It has been established that the absolute number of S. calcitrans subpopulation can be as high as 100,000 specimens per a farmyard. The possibilities of using indices of the relative number of flies (caught on fly-paper) for estimation of the absolute number of these insects in the housings of farms have been found out.     

Biological control of house flies Musca domestica and stable flies Stomoxys calcitrans(Diptera: Muscidae) by means of inundative releases of Spalangia cameroni(Hymenoptera: Pteromalidae)

The efficacy of the pupal parasitoid Spalangia cameroni Perkins as a biological control agent was tested against house flies Musca domestica Linnaeus and stable flies Stomoxys calcitrans (Linnaeus) in one dairy cattle and two pig installations in Denmark. Weekly releases of S. cameroni from April through to September-October 1999 and 2000 resulted in significant suppressions of house fly populations to below nuisance level, whereas no effect on stable flies was found. Parasitism was significantly higher in the release years compared to the control years, but was below 25% averaged over the fly season for each farm. A statistical model based on a functional relationship between the innate capacity of increase of the two fly species and three explanatory variables (air temperature, fly density and parasitism) provided a fairly good fit to data with the abundances of house flies and stable flies explained mostly by temperature, but intra- and interspecific competition, and parasitism had a significant effect as well. Overall, the model was capable of explaining 14% and 6.6% of the total variation in data for house fly and stable fly, respectively. Spalangia cameroni was the predominant parasitoid to emerge from exposed house fly pupae, but from mid summer onwards Muscidifurax raptor Girault & Sanders (Hymenoptera: Pteromalidae) was also quite common. The study indicated that biological control of house flies can be an efficient alternative to chemical control.     

Isolation and in vitro synthesis of trypsin from the biting fly,Stomoxys calcitrans

The synthesis of [3H]trypsinlike enzyme by the fat body was followed in Stomoxys calcitransin vitro using a radioimmunoassay (RIA) developed against mammalian trypsin. Using high specific activity [3H]valine, trypsinlike activity was followed in midgut epithelial cells, thoracic muscle, and fat body removed from sugar-fed flies. Excreta protease of S. calcitrans was partially purified using charge and hydroxylapatite gel chromatography. Seventy-five percent of the enzyme eluted from these gels was inhibited by tosyl-L-lysine chloromethyl ketone HCI (TLCK) and was classified as trypsinlike. Electrophoresis of the trypsinlike enzyme indicated that it was only 50% pure. Trypsinlike activity from S. calcitrans bound to α₁-globulin IV-I and formed a complex that was dissociated on a P-100 Bio-Gel column. Binding between the protease and the α₁-gobulin IV-I caused a 1.4-fold increase in the apparent molecular weight of the protease on the P-100 Bio-Gel column. Trypsinlike activity was characterized in the midgut and excreta by affinity binding to covalently linked TLCK and tosyl-L-lysine chloromethyl ketone HCI (TAME)Sepharose 4B gels. Between 50% and 55% of the excreta protease and 5669% of the midgut protease bound to the affinity gels and was trypsinlike. Protease activity that did not bind to the gels was not inhibited by TLCK and did not have the esterolytic activity of trypsin.     

Mechanical transmission of Trypanosoma evansi and T. congolense by Stomoxys niger and S. taeniatus in a laboratory mouse model

Abstract .Mechanical transmission of Trypanosoma evansi (South American origin) and T. congolense of Kilifi DNA type (Kenyan origin) was studied in laboratory mice using the African stable flies Stomoxys niger niger and S. taeniatus . Altogether, 355 flies were interrupted after feeding on infected blood and then transferred immediately to an uninfected mouse to complete feeding. Microscopy and subinoculation of triturated flies into uninfected mice demonstrated the survival of T. congolense in Stomoxys for up to 210 min and T. evansi for up to 480 min. Parasites survived for much longer periods in the digestive tract than inside or on the mouthparts. Trypanosoma congolense was transmitted only by S. n. niger , and only at low rates of 3, 8 and 10% using flies of different feeding histories: fed on blood the previous day, freshly caught, and teneral. Trypanosoma evansi was transmitted by both Stomoxys species at higher rates: S. taeniatus range 13–18%; S. n. niger range 17–35%. The highest transmission rate occurred with the combination of teneral S. n. niger and T. evansi.     

Ovarian development in the stable fly, Stomoxys calcitrans, in relation to diet and juvenile hormone control

ABSTRACT. When female Stomoxys calcitrans were supplied a daily blood-meal their polytrophic ovaries developed and deposited yolk, whereas those of females fed only 5% sucrose deposited no yolk and remained in a 'resting' condition. Longevity of the sugar-fed flies was also reduced. Blood feeding was thus obligatory for general metabolism as well as reproduction. The follicles did not develop in females allatectomized within 1 h of emergence, irrespective of diet, and degenerated if blood was not provided. If blood was available the follicles did not degenerate, nor did they accumulate yolk. In both circumstances development was restored by implanting corpora allata. If allatectomy was delayed until 72 h after eclosion the follicles of sugar-fed flies developed to the resting stage, and those of blood-fed flies deposited yolk.     

Efficacy of cyromazine to control immature stable flies (Diptera: Muscidae) developing in winter hay feeding sites

Hay mixed with manure and urine residues at sites where hay has been provided as supplemental winter feed for cattle provide an excellent substrate for the development of immature stable flies, Stomoxys calcitrans (L.). Such sites are primary sources of early summer stable flies in the central United States and no effective measures are currently available to control fly development in them. A single application of granular cyromazine in May provided 97% reduction in the number of adult stable flies emerging from hay feeding sites. Stable fly control did not decline during the 12 wk season. A small decline in control was observed relative to anthomyiid, sarcophagid, and syrphid flies developing in the hay feeding sites. However, none of those flies are considered to be pests and > or = 50% control of those flies was maintained for 65 d after application. Cyromazine offers a safe and affordable option for the control of immature stable flies developing in winter hay feeding sites. Controlling those flies should reduce the estimated $2 billion per year of lost production in U.S. cattle industries attributable to stable flies.     

同域分布鼬獾和食蟹獴活动节律的比较

为探明同域分布的鼬獾(Melogale moschata)和食蟹獴(Herpestes urva)的日活动节律、时间生态位及其两者共存机制,于2016年12月至2017年12月,在广西弄岗国家级自然保护区开展红外相机监测获取数据,后采用核密度估计(Kernel density estimation)和重叠指数(Coefficient of overlap)对该地区的鼬獾和食蟹獴进行了研究。结果表明:鼬獾属于典型的夜行性动物,其日活动模式为双峰型,活动峰值出现在01:00—05:00和21:00—24:00;与雨季相比,旱季的活动峰值均提前1 h,活动高峰期延长3 h。食蟹獴为典型昼行性动物,其日活动模式为单峰型,活动峰值出现在11:00—18:00,与雨季相比,旱季活动高峰期提前并延长1 h。两者间的日活动模式重叠指数较低(Δ=0.17),但旱季(Δ=0.22)高于雨季(Δ=0.12)。两者主要通过改变时间生态位来避免对食物资源和领域的竞争,从而实现共存。     

Stable fly, Stomoxys calcitrans, mouthpart removal influences stress and anticipatory responses in mice

Abstract Biting fly attack induces a variety of stress and anxiety related changes in the physiology and behaviour of the target animals. Significant reductions in pain, or more appropriately, nociceptive sensitivity (latency of a foot-lifting response to an aversive thermal stimulus), are evident in laboratory mice after a 1 h exposure to stable flies, Stomoxys calcitrans. The role of the various components of biting fly attack in the development of this stress-induced reduction in pain sensitivity (analgesia) is, however, unclear. This study demonstrates that fly-naive mice do not exhibit a stress-induced analgesia when exposed to stable flies whose biting mouthparts have been removed. In contrast, mice that have been previously exposed to intact stable flies exhibit significant analgesia when exposed to flies that are incapable of biting. However, the level of analgesia induced is lower than that elicited by exposure to intact stable flies. Exposure to non-biting house flies, Musca domestica , has no effect on nociceptive sensitivity. It appears that the actual bite of the stable fly is necessary for the induction of analgesia and probably other stress and anxiety associated responses in fly naive mice. However, mice rapidly learn to recognize biting flies and exhibit significant, possibly anticipatory analgesic responses to the mere presence of biting flies.