Using modified trapping regimes to understand the behavioral and spatial ecology of Philornis downsi (Diptera: Muscidae).

The avian vampire fly Philornis downsi (Dodge & Aitken) (Diptera: Muscidae) is native to continental South America and the Caribbean, but invasive in the Galapagos Archipelago. The larvae of P. downsi feed on the blood and tissues of the nestlings of 75% of the small land bird species that are endemic or native to Galapagos, causing high in-nest mortality and severe population declines in some species. Efficient trapping techniques are vital to safeguarding these birds in the short term as well as for monitoring fly populations, but basic information about the ecology of the fly is still needed to help develop a species-appropriate trapping method. In this study, we used a novel trapping regime with a vertical distribution to make inferences about P. downsi's behavioral and spatial ecology and to optimize trap catch. Our results showed that male and female P. downsi were trapped in greater numbers below the canopy (3.1-7.5 m), lower down than other commonly caught insect species (5.1-11.5 m). Notably, the effect of trap height remained consistent across seasons and different weather conditions. These findings suggest that P. downsi tend to move at heights where their hosts nest (at or below the canopy) and do not spend time above the canopy. This also makes it unlikely that strategies such as hill-topping or aerial swarming are being used to locate mates. As such, trapping and control efforts should be focused below the canopy in forests with similar canopy heights to effectively capture P. downsi and reduce bycatch of other insects.

Spatiotemporal distribution of hematophagous flies (Diptera: Muscidae) on beef cattle farms in Bangkok, Thailand.

A spatiotemporal investigation of hematophagous fly prevalence was conducted over a 1-year period on 12 beef cattle farms located in major livestock areas of Bangkok, Thailand, using Vavoua traps. The survey revealed 5,018 hematophagous flies belonging to Muscidae and Tabanidae, with the 3 dominant species identified as Stomoxys calcitrans (Linnaeus) (2,354; 46.91%), Musca crassirostris Stein (1,528; 30.45%), and Haematobia exigua de Meijere (922; 18.37%). The abundance of S. calcitrans per trap per week was significantly higher during the rainy season (45.64 ±â€…14.10), followed by the cold and dry seasons (6.39 ±â€…2.16 and 3.04 ±â€…1.27, respectively). The relative abundance of S. calcitrans reached the highest apparent density per trap per day (ADT) index of 9.83 in August 2022 during the rainy season. Subsequently, there was a rapid decline, and the ADT index dropped to nearly zero in December 2022 during the cold season. This low abundance continued through the dry months from March to May 2023. The higher rainfall and relative humidity could significantly contribute to the high relative abundance of S. calcitrans. In contrast, M. crassirostris and H. exigua showed population fluctuations that were not significantly associated with seasonal changes and weather conditions. Remote sensing data and spatial regression analyses using ordinary least squares regression showed the high spatial density of S. calcitrans in the north direction of the Khlong Sam Wa district during the rainy season; it shifted toward the south in the cold and dry seasons, corresponding with rainfall.

Stable flies sense and behaviorally respond to the polarization of light.

Insects use their polarization-sensitive photoreceptors in a variety of ecological contexts including host-foraging. Here, we investigated the effect of polarized light on host foraging by the blood-feeding stable fly, Stomoxys calcitrans, a pest of livestock. Electroretinogram recordings with chromatic adaptation demonstrated that the spectral sensitivity of stable flies resembles that of other calyptrate flies. Histological studies of the flies' compound eye revealed differences in microvillar arrangement of ommatidial types, assumed to be pale and yellow, with the yellow R7 and pale R8 photoreceptors having the greatest polarization sensitivity. In behavioural experiments, stable flies preferred to alight on horizontally polarized stimuli with a high degree of linear polarization. This preferential response disappeared when either ultraviolet (UV) or human-visible wavelengths were omitted from light stimuli. Removing specific wavelength bands further revealed that the combination of UV (330-400 nm) and blue (400-525 nm) wavelength bands was sufficient to enable polarized light discrimination by flies. These findings enhance our understanding of polarization vision and foraging behavior among hematophagous insects and should inform future trap designs.

Persistence of the invasive bird-parasitic fly Philornis downsi over the host interbreeding period in the Galapagos Islands.

Many parasites of seasonally available hosts must persist through times of the year when hosts are unavailable. In tropical environments, host availability is often linked to rainfall, and adaptations of parasites to dry periods remain understudied. The bird-parasitic fly Philornis downsi has invaded the Galapagos Islands and is causing high mortality of Darwin's finches and other bird species, and the mechanisms by which it was able to invade the islands are of great interest to conservationists. In the dry lowlands, this fly persists over a seven-month cool season when availability of hosts is very limited. We tested the hypothesis that adult flies could survive from one bird-breeding season until the next by using a pterin-based age-grading method to estimate the age of P. downsi captured during and between bird-breeding seasons. This study showed that significantly older flies were present towards the end of the cool season, with ~ 5% of captured females exhibiting estimated ages greater than seven months. However, younger flies also occurred during the cool season suggesting that some fly reproduction occurs when host availability is low. We discuss the possible ecological mechanisms that could allow for such a mixed strategy.

Antennal and palpal sensilla of three predatory Lispe species (Diptera: Muscidae): an ultrastructural investigation.

Antennae and maxillary palps are the most important chemical reception organs of flies. So far, the morphology of antennae and maxillary palps of flies of most feeding habits have been well described, except for that of relatively rare aquatic predatory species. This study describes sensilla on antennae and maxillary palps of three aquatic predatory Lispe species: Lispe longicollis, L. orientalis and L. pygmaea. Types, distribution, and density of sensilla are characterised via light and scanning electron microscopy. One type of mechanoreceptors is found on antennal scape. Mechanoreceptors (two subtypes) and one single pedicellar button (in L. pygmaea) are located on antennal pedicel. Four types of sensilla are discovered on antennal postpedicel: trichoid sensilla, basiconic sensilla (three subtypes), coeloconic sensilla and clavate sensilla. A unique character of these Lispe species is that the coeloconic sensilla are distributed sparsely on antennal postpedicel. Mechanoreceptors and basiconic sensilla are observed on the surface of maxillary palps in all three species. We demonstrated clear sexual dimorphism of the maxillary palps in some of the Lispe species, unlike most other Muscidae species, are larger in males than females. This, along with their courtship dance behaviour, suggest their function as both chemical signal receiver and visual signal conveyer, which is among the few records of a chemical reception organ act as a signal conveyer in insects.

Stable fly activity is associated with dairy management practices and seasonal weather conditions.

Stable flies (Stomoxys calcitrans) are blood-sucking insects commonly associated with cattle production systems worldwide and are known to cause severe irritation to cattle due to painful bites. Cattle react to biting stable flies with an aggregating behavior known as bunching. Bunching behavior reduces grazing or feed consumption and thus reduces cattle productivity and welfare. Cattle's fly-repelling behaviors include foot stomping, head tossing, tail switching and skin twitching. A longitudinal study was conducted in 2017 on 20 California dairies (average lactating herd size = 2,466 (SE±28.392)) during the stable fly season from April to July. The study objectives were to estimate the association between environmental factors and dairy characteristics including facility design, feed and manure management, total mixed ration (TMR) components fed to cattle, and operational pest management procedures and the outcome stable fly activity on California dairies. Stable fly activity was measured by counting stable flies on cow forelimbs (leg count) and on Alsynite traps (trap count) over the 13-week study period. Weekly leg counts were performed for cattle in lactating cow pens (31 pens from 10 study dairies) with counts made during the morning (AM) and again during the afternoon (PM). Trap counts were performed on all 20 study dairies. Data were analyzed using linear mixed models which revealed temporal variation in the average leg and trap counts with stable fly activity increasing from May to June and then decreasing to the lowest activity in July. Leg counts were higher during the afternoon compared to morning. Ambient temperatures ≤30°C and relative humidity (RH) measurements <50% were associated with higher leg and trap counts. Traps located at the periphery of study dairies had higher stable fly counts compared to traps located in the interior of the dairy. Cow pens with trees on the periphery had higher leg counts in comparison to pens away from trees. Specific TMR components were associated with both leg and trap counts. Dairies feeding by-products including almond hulls, wet distillers' grain, fruits, and vegetables had higher trap counts compared to dairies that did not feed these ingredients. At the pen level, pens with rations that contained straw had lower average leg counts compared to pens fed with rations that did not contain straw. A similar association was observed for pens with rations that contained wheat silage when ambient temperatures were ≤30°C. In contrast, pens with water added to the TMR while the RH was ≥50% had higher average leg counts compared to pens without water added to the TMR. Dairies that applied insecticides for fly control to their entire facility had lower trap counts compared to dairies that did not apply insecticides. Stable fly activity measured on California dairies using leg and trap counts varied according to the month, environmental factors, pen surroundings, trap location, TMR components, and insecticide use.

Detection and distribution of haematophagous flies and lice on cattle farms and potential role in the transmission of Theileria orientalis.

On the Northern Tablelands of New South Wales, Australia, endemic Theileria orientalis infection of cattle has been reported on farms where no ticks have been observed, raising the question of how Theileria is transmitted in these areas. To investigate the potential role of mechanical transmission by insects, the present study investigated the seasonal dynamics of biting fly species trapped between December 2017 and May 2019 on six cattle farms in the region where the presence of Theileria was confirmed. These flies, sucking lice collected from these farms and pools of Culicoides species affecting cattle also trapped in the region were subjected to qPCR detection of T. orientalis. Eleven species from eight genera of biting flies were collected using unbaited Nzi traps. Tabanid species were present in all farms, with Dasybasis oculata (43.6 %) and D. circumdata (27.6 %) being the most abundant and widespread species. The effect of season on the mean count per trapping event was statistically significant and highest in the summer months for Lilaea fuliginosa and D. oculata, and the autumn months for D. circumdata, with no seasonal effect on the abundance of the undescribed Dasybasis spp. No biting flies were trapped during the winter months. Sucking (Linognathus vituli and Haematopinus eurysternus) and biting (Bovicola bovis) cattle lice were also collected from all farms with the latter detected in only one farm. PCR screening for T. orientalis of trapped hematophagous insects resulted in parasite detection in the tabanid and Stomoxyini flies, biting midges and sucking lice with the highest proportion of positive samples for Haematopinus eurysternus (4/4 pools) and H. irritans exigua (6/15 individuals). The detection of the parasite in these potential vectors indicates a possible role in the mechanical transmission of T. orientalis and may partly explain the ubiquitous presence of Theileria in areas where ticks are absent.

First Life Table of Synthesiomyia nudiseta (Diptera: Muscidae) From Palearctic Region for Analyzing the Effect on Its Dispersal Ability.

To better understand the population dynamics and dispersal ability of insect species, it is often helpful to derive a life table containing fundamental demographic data. The aim of this study was to determine a life table for the predatory necrophagous species Synthesiomyia nudiseta (van der Wulp, 1883) on a pig liver diet and under controlled laboratory conditions (29.5 ± 2. 5°C, RH 50 ± 15%, and a photoperiod of 12:12). This species has medical and veterinary importance and its distribution extends in tropical and subtropical areas and now it has been established in the southwestern of Europe. The mean adult longevity was 36. 18 ± 2. 06 d and the net reproduction rate, R, was 27.65 offspring/female, the mean generation time, T, was 22. 09 d, the finite rate of increase, λ, was 1. 16 d-1, and the intrinsic rate of increase, r, was 0. 15 d-1. These results indicate that S. nudiseta cannot be considered an r-strategist as the most common synanthropic necrophagous blowflies due to its predatory behavior; however, its invasive and colonist abilities are discussed. This is the first life table study of this species from Palearctic region to analyze the effect of its dispersal ability.

Shared volatile organic compounds between camel metabolic products elicits strong Stomoxys calcitrans attraction.

The sources of animal odours are highly diverse, yet their ecological importance, in host-vector communication, remains unexplored. Here, using the camel (host)-Stomoxys calcitrans (vector) interaction, we collected and analyzed the Volatile Organic Compounds (VOCs) of camels from four of its different odour sources: breath, body (skin), urine, and dung. On non-metric model multivariate analyses of VOCs we show that substantial chemo-diversity exists between metabolic products associated with an individual camel. VOCs from the four metabolic products were distinct and widely segregated. Next, we show electrophysiologically, that VOCs shared between metabolic products activated more Olfactory Sensory Neurons (OSNs) and elicited strong behavioural attractive responses from S. calcitrans under field conditions independent of geography. In our extended studies on house flies, the behavioural response to these VOCs appears to be conserved. Overall, our results establish that VOCs from a range of metabolic products determine host-vector ecological interactions and may provide a more rigorous approach for discovery of unique and more potent attractants.

The combined effects of temperature and relative humidity parameters on the reproduction of Stomoxys species in a laboratory setting.

In this study, Stomoxys species (S. calcitrans, S. sitiens and S. indica) were examined to improve on the current technique for mass rearing using a method of combined incubation parameters. Moreover, the reproductive potential of immature forms at various stages of development was defined. Immature forms of stable flies were incubated according to species. There was no significant difference in the number of immature forms obtained among species incubated under the same conditions. Six incubation parameters were used in combination, at temperatures (T) of 32°C, 27°C and 22°C and relative humidity (RH) of 90% and 70% RH. The combined method resulted in a higher number of eggs hatching at 32°C and 90% humidity as well as an increase in the number of larva pupated and emergence of imago at 27°C and 70% humidity.

Evaluation of Filth Fly Species Composition and Abundance Using Two Monitoring Methods in Swine Confinement Housing.

Concentrated swine production can produce large amounts of accumulated waste that may serve as development sites for pest flies. Filth flies are not only a nuisance but can also interfere with animal growth and production and are capable of mechanically transmitting many pathogens to swine on confinement facilities. In addition to production and health concerns, high populations of filth flies developing on concentrated animal facilities may subject producers to nuisance litigation. While litigation against livestock producers associated with pest filth flies has become more frequent and high profile, information on the filth fly fauna in swine facilities in the United States is limited. In this study, filth fly species diversity and population fluctuations were monitored with spot and sticky cards in one sow facility and two finishing facilities in North Carolina. House flies Musca domestica L. (Diptera: Muscidae) were the dominant species followed by black dump flies Hydrotea (Ophyra) aenescens Weidemann (Diptera: Muscidae). A difference was seen in total spots on cards placed in more central barn locations than towards the outer walls in the sow facility but not the finishing facilities. Mean spots at only one of the finishing facilities exceeded the conventional control threshold of 100 spots/week, in May and June. Fly numbers decreased naturally in the following months, suggesting that standard control thresholds may not accurately inform filth fly control efforts in swine production. Due to their complementary nature, both spot and sticky cards placed in representative locations throughout barns are recommended. However, more swine-specific information is needed for optimizing monitoring methods.

More than just nestlings: incidence of subcutaneous Philornis (Diptera: Muscidae) nest flies in adult birds.

Philornis flies Meinert (Diptera: Muscidae) have been documented parasitizing over 250 bird species, some of which are endemic species threatened with extinction. Philornis parasitism is hypothesized to affect nestlings disproportionately more than adult birds because limited mobility and exposed skin of nestlings increase their vulnerability to parasitism. We used a comprehensive literature review and our recent fieldwork in the Dominican Republic, Puerto Rico, and Grenada to challenge the idea that parasitism by subcutaneous Philornis species is a phenomenon primarily found in nestlings, a fact that has not been quantified to date. Of the 265 reviewed publications, 125 (49%) reported incidences of parasitism by subcutaneous Philornis, but only 12 included the sampling of adult breeding birds. Nine of these publications (75%) reported Philornis parasitism in adults of ten bird species. During fieldwork in the Dominican Republic, Puerto Rico, and Grenada, we documented 14 instances of parasitism of adult birds of seven avian species. From literature review and fieldwork, adults of at least fifteen bird species across 12 families and four orders of birds were parasitized by at least five Philornis species. In both the published literature and fieldwork, incidences of parasitism of adult birds occurred predominantly in females and was frequently associated with incubation. Although our findings indicate that Philornis parasitism of adult birds is more common than widely presumed, parasite prevalence is still greater in nestlings. In the future, we recommend surveys of adult birds to better understand host-Philornis relationships across life stages. This information may be essential for the development of effective control measures of Philornis to ensure the long-term protection of bird species of conservation concern.

Flies Exploit Predictable Perspectives and Backgrounds to Enhance Iridescent Signal Salience and Mating Success.

Communication requires both the encoding of information and its effective transmission, but little is known about display traits that primarily serve to enhance efficacy. Here we examined the visual courtships of Lispe cana, a cursorial fly that lives and mates in heterogeneous foreshores, and tested the prediction that males should seek to enhance signal salience and consequent fitness through the flexible choice of display locations. We show that courting males access the field of view of females by straddling them and holding their wings closed before moving ahead to present their structurally colored faces in ritualized dances. Males preferentially present these UV-white signals against darker backgrounds and the magnitude of contrast predicts female attention, which in turn predicts mating success. Our results demonstrate a striking interplay between the physical and attentional manipulation of receivers and reveal novel routes to the enhancement of signal efficacy in noisy environments.

Responses of the putative trachoma vector, Musca sorbens, to volatile semiochemicals from human faeces.

The putative vector of trachoma, Musca sorbens, prefers to lay its eggs on human faeces on the ground. This study sought to determine whether M. sorbens females were attracted to volatile odours from human faeces in preference to odours from the faeces of other animals, and to determine whether specific volatile semiochemicals mediate selection of the faeces. Traps baited with the faeces of humans and local domestic animals were used to catch flies at two trachoma-endemic locations in The Gambia and one in Ethiopia. At all locations, traps baited with faeces caught more female M. sorbens than control traps baited with soil, and human faeces was the most successful bait compared with soil (mean rate ratios 44.40, 61.40, 10.50 [P<0.001]; 8.17 for child faeces [P = 0.004]). Odours from human faeces were sampled by air entrainment, then extracts of the volatiles were tested by coupled gas chromatography-electroantennography with laboratory-reared female M. sorbens. Twelve compounds were electrophysiologically active and tentatively identified by coupled mass spectrometry-gas chromatography, these included cresol, indole, 2-methylpropanoic acid, butanoic acid, pentanoic acid and hexanoic acid. It is possible that some of these volatiles govern the strong attraction of M. sorbens flies to human faeces. If so, a synthetic blend of these chemicals, at the correct ratios, may prove to be a highly attractive lure. This could be used in odour-baited traps for monitoring or control of this species in trachoma-endemic regions.

Daily and seasonal variation of muscid flies (Diptera: Muscidae) in Chiang Mai province, northern Thailand.

Flies of the family Muscidae, or muscids, are of medical and veterinary importance worldwide due to their recognition as nuisance pests and myiasis-producing agents. Effective control of muscids requires biological information on population dynamics daily and across seasons. In this study, such patterns were investigated in three different microhabitats (e.g., forest area, palm plantation and longan orchard) in a suburban area of Chiang Mai Province, northern Thailand. Adult fly samplings were conducted for 24-h intervals using semiautomatic traps and 1-day old beef offal as bait. Samplings were carried out twice per month from July 2013 to June 2014. A total of 3,419 muscids were trapped, comprising nine species, with Musca domestica Linnaeus accounting for the majority (n = 1,329; 38.9%) followed by Hydrotaea spinigera Stein (n = 770; 22.5%) and Musca ventrosa Wiedemann (n = 740; 21.7%). The greatest overall abundance was in the longan orchard location (n = 1,508; 44.1%). Community structure peaked during the rainy season (mid-May to mid-Oct). Peak activity during the day was late morning (9.00 to 12.00 h) for M. domestica, early morning (6.00 to 9.00 h) for H. spinigera, and early afternoon (12.00 to 15.00 h) for M. ventrosa. Temperature had no significant effect on the abundance of M. domestica (rs= -0.030, p = 0.576) or H. spinigera (rs = 0.068, p = 0.200), but had a weak negative correlation with M. ventrosa (rs = -0.238, p = 0.0001). Relative humidity had a weak negative correlation with M. domestica (rs = -0.263, p = 0.0001), H. spinigera (rs = -0.107, p = 0.043) and M. ventrosa (rs = -0.344, p = 0.0001). More females (n = 2,078) were trapped than males (n = 761). These results provide baseline information of daily and seasonal dynamic activity of muscid flies under natural conditions, which is the prerequisite information for effective control measures.

Species Composition and Abundance of Stomoxys spp. (Diptera: Muscidae) in Peninsular Thailand.

Stable fly collections were conducted to study the species composition and daytime activity of Stomoxys spp. (Diptera: Muscidae) in Peninsular Thailand (Songkhla, Trang, Pattalung, Nakon Si Thammarat, and Satun provinces). Vavoua traps were used for fly collections in wet and dry seasons each year. Four Stomoxys species were found, S. calcitrans (L.) (Diptera: Muscidae) being the most common with 2,512 specimens (87.43% of captures), followed by S. indicus (Picard) (Diptera: Muscidae) with 306 specimens (10.65%), S. sitiens (Rondani) (Diptera: Muscidae) with 44 specimens (1.53%), and S. uruma (Shinonaga and Kano) (Diptera: Muscidae) with 11 specimens (0.39%). Subsequently, Songkhla Province was further selected to be a potential collection site to conduct a 1-yr abundance study, due to mixed crop-livestock farming in one place. Stomoxys calcitrans was predominant from 0800 to 1000 h with 4,921 specimens (93.6%) while S. indicus with 317 specimens (6%) and S. sitiens with 19 specimens (0.4%) were numerically dominant from 0600 to 0800 and 1600 to 1800 h. A proportion of male and female of each species was also established. This overall finding could be used as an ideal for nationwide species distribution status for the guidance of appropriate fly control. This information can lighten the way for the future control measures program activity of stable flies in Thailand.

Inferences about the transmission of lumpy skin disease virus between herds from outbreaks in Albania in 2016.

Lumpy skin disease has recently emerged as a major threat to cattle populations outside of Africa, where it is endemic. In 2015 the first ever European outbreaks occurred in Greece, which were followed by spread across much of the Balkans in 2016. Here we use a simple mathematical model for the transmission of lumpy skin disease virus (LSDV) between herds to explore factors influencing its spread by fitting it to data on outbreaks in Albania in 2016. We show that most transmission occurs over short distances (<5 km), but with an appreciable probability of transmission at longer distances. We also show that there is evidence for seasonal variation in the force of infection associated with temperature, possibly through its influence on the relative abundance of the stable fly, Stomoxys calcitrans. These two results together are consistent with LSDV being transmitted by the bites of blood-feeding insects, though further work is required to incriminate specific species as vectors. Finally, we show that vaccination has a significant impact on spread and estimate the vaccine effectiveness to be 76%.

Necrophagous Fly Assembly: Evaluation of Species Bait Preference in Field Experiments.

The assembly of species that colonize animal organic matter, their relative abundance, and dynamics are affected by the environmental and biogeographical conditions to which these resources are exposed. Baited trap studies are essential for research on the diversity, seasonality, distribution and population dynamics of necrophagous flies. Decomposing baits provide the necessary stimulus for flies to aggregate on them. In this study, three types of bait of animal origin with different organic chemical composition were compared in terms of the diversity, richness, abundance, and species composition of saprophagous flies species that were attracted to them. Bone-meal (BM), cow liver (CL), and rotten chicken viscera (CV) were used as bait to collect flies. In total, 3,387 Calliphoridae, Sarcophagidae, and Muscidae adult flies were collected. The most abundant species were Lucilia ochricornis (Wiedemann 1830), Chrysomya albiceps (Wiedemann 1819) (Diptera: Calliphoridae), Peckia (Sarcodexia) lambens (Wiedemann 1830) (Diptera: Sarcophagidae), and Ophyra capensis (Wiedemann 1818) (Diptera: Muscidae). The type of bait had significant effects on both the total richness (F2,18 = 57.08; P < 0.0001) and the effective number of species (F2,18 = 12.81; P = 0.0003) per trap. The average richness was higher in traps baited with chicken viscera, followed by cow liver and finally by bone-meal. The composition of cow liver and bone meal species constitute subsets of the species collected with chicken viscera, thus using the three baits would not increase the number of species detected. These results indicate that chicken viscera is the most efficient bait for testing or assessing necrophagous fly diversity.

Geographical Distribution, Biodiversity, and Species Richness of Medically Important Necrophagous Flies in Central Iran.

There have been some investigations carried out about necrophagous flies and their biodiversity indices in Iran. In the present study, the species composition of flies, their richness, and biodiversity were investigated in central Iran. In a cross-sectional study, specimens were collected monthly in three different climate areas of Qom Province. Species diversity, species richness, and species evenness were calculated to estimate the species biodiversity of flies. In total, 7,291 flies were collected and identified using valid identification keys that classified flies into four families and 15 different species. The largest collection of flies was obtained in the mountainous areas comprising 36.2% of specimens. Moreover, five forensically important species of fly were collected in this region with the potential to cause human and animal myiasis: Calliphora vicina, Lucilia sericata, Musca domestica, Wohlfahrtia nuba, and Chrysomya albiceps. There were slight differences in species richness and diversity indices in the areas. In mountainous areas, the Shannon-Wiener index and richness were maximum (H' = 1.87, S = 13). The evenness based on the Shannon evenness index in the mountainous areas was 0.728 and 0.719 in desert areas, whereas it was the highest (0.764) in the semidesert areas. Moreover, high values of the Jaccard similarity index were observed in captured necrophagous fly species in all the areas. The necrophagous fly fauna and species diversity indices were high because of an increase in the evenness. In general, some well-known forensically important species of flies were collected that proved the potential of myiasis occurrence in this area.

Risk factors affecting dairy cattle protective grouping behavior, commonly known as bunching, against Stomoxys calcitrans (L.) on California dairies.

Bunching is the term used to describe the protective aggregating behavior of cattle against the painful bites of stable flies (Stomoxys calcitrans), where cattle gather in a group with their heads to the center of the group and their tails to the outside to reduce stable fly attack. Both sexes of the stable fly feed on blood, and their painful bites negatively impact cattle health, productivity and welfare. A longitudinal study was conducted from April to July 2017 to estimate the stable fly activity on 20 California dairies (average herd size = 2466 ± 1050), to determine stable fly activity that induced bunching, and to evaluate the association between management and environmental factors, and cattle bunching. Stable fly activity was recorded weekly using trap counts and leg counts. Data was analyzed using linear mixed models with odds ratio. Cattle bunching at the dairy level was predicted by mean trap counts of ≥150 flies/trap/week, while bunching at the pen level was predicted by mean leg counts >1 fly/leg/cow or mean trap counts >50 flies/trap/week for traps closest to the pen. Additional risk factors predicting cattle bunching at the dairy level were study week (May/June vs July), presence of crops adjacent to dairy >2 sides, and feeding wet distillers grain. Additional risk factors predicting cattle bunching at the pen level were study week (May/June vs July), ambient temperature ≤30°C, pen design (freestall vs open dry lot or bedded pack), production status (lactating/dry vs close-up), presence of crops surrounding cattle pens, feeding rations containing molasses. Cattle bunching was reduced at the pen level by relative humidity >50%, and when the cattle pen was surrounded by other cattle pens or was bordered by a main road. At the dairy level, removal of manure along fence lines of cattle pens was protective against cattle bunching.