Mesostigmata diversity by manure type: a reference study and new datasets from southwestern Iran

Manure-inhabiting Mesostigmata mites are important biological control agents of pest flies. However, the biodiversity of this mite community is mainly known from Europe and America, and especially from cattle manure. This study examined the diversity and abundance of Mesostigmata mites associated with various types of manure in an (intensive) agricultural region of the Middle East, i.e., the city Ahvaz and its suburbs, in southwest Iran. Mite samples were extracted from manure of cattle, buffalo, sheep, horse, poultry and quail in 30 livestock and poultry farms. In total, 40 species belonging to 24 genera and 16 families were identified. The most diverse families were Laelapidae with eight species, Macrochelidae with seven and Parasitidae with six. Macrocheles muscaedomesticae and Uroobovella marginata were the most widespread species, recorded in 28 and 27 out of 30 collection sites, respectively. Two species, M. sumbaensis and U. marginata, were found in all studied manures. Simpson's diversity index recorded the highest diversity in buffalo and sheep manure. Real and theoretical species richness (rarefaction curves) were congruent in number of individuals. The presence of seven species of Macrochelidae in the manure confirms that these are important predators of the house fly for the region of Ahvaz and its suburbs. Members of the Parasitidae were highly prevalent, with one species known as a specialized predator of house fly eggs. This work aims to encourage further studies on the diversity of Mesostigmata in these agricultural settings, and further continue assessing the feasibility of these mites as effective biocontrol agents of filth flies in different types of manure and from different corners of the world.

in Musca spp.: Detection Using Molecular Approaches

Objective

This study aimed to detect the presence of Wolbachia and Spiroplasma endosymbionts in Musca flies through molecular approaches.

Methods

In total, 40 Musca spp. (20 female and 20 male) were used. Before DNA extraction, the flies were dissected and their heads, wings and legs were detached from their bodies under a stereomicroscope. Genomic DNA was analysed by standard polymerase chain reaction (PCR) using primers against Musca beta-tubulin. Afterward, the samples were examined for the presence of Wolbachia spp. using primers against Wolbachia wsp and GroEL. Furthermore, the DNA samples were analysed by PCR to detect the presence of Spiroplasma using primers against the 16S rRNA.

Results

No Wolbachia positivity was detected in Musca flies, as shown by the negative PCR results for wsp and GroEL. Spiroplasma positivity was detected in 5% (1/20) of the female Musca flies but not in the male flies (0/20).

Conclusion

Wolbachia spp. were not detected in Musca flies. Of the total Musca flies, only one was positive for Spiroplasma spp. To our knowledge, this is the first study to detect the presence of Spiroplasma in Musca flies.

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 (r_s= -0.030, p = 0.576) or H. spinigera (r_s = 0.068, p = 0.200), but had a weak negative correlation with M. ventrosa (r_s = -0.238, p = 0.0001). Relative humidity had a weak negative correlation with M. domestica (r_s = -0.263, p = 0.0001), H. spinigera (r_s = -0.107, p = 0.043) and M. ventrosa (r_s = -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.

Local deformation and stiffness distribution in fly wings

Mechanical properties of insect wings are essential for insect flight aerodynamics. During wing flapping, wings may undergo tremendous deformations, depending on the wings’ spatial stiffness distribution. We here show an experimental evaluation of wing stiffness in three species of flies using a micro-force probe and an imaging method for wing surface reconstruction. Vertical deflection in response to point loads at 11 characteristic points on the wing surface reveals that average spring stiffness of bending lines between wing hinge and point loads varies ∼77-fold in small fruit flies and up to ∼28-fold in large blowflies. The latter result suggests that local wing deformation depends to a considerable degree on how inertial and aerodynamic forces are distributed on the wing surface during wing flapping. Stiffness increases with an increasing body mass, amounting to ∼0.6 Nm⁻¹ in fruit flies, ∼0.7 Nm⁻¹ in house flies and ∼2.6 Nm⁻¹ in blowflies for bending lines, running from the wing base to areas near the center of aerodynamic pressure. Wings of house flies have a ∼1.4-fold anisotropy in mean stiffness for ventral versus dorsal loading, while anisotropy is absent in fruit flies and blowflies. We present two numerical methods for calculation of local surface deformation based on surface symmetry and wing curvature. These data demonstrate spatial deformation patterns under load and highlight how veins subdivide wings into functional areas. Our results on wings of living animals differ from previous experiments on detached, desiccated wings and help to construct more realistic mechanical models for testing the aerodynamic consequences of specific wing deformations.

Summary: We determined mechanical properties of wings under load in three fly species. Fly wings broadly deform similar to homogenous beams. Veins and joints shape wing mechanics and govern wing deformation during flapping flight.

Mycoplasma conjunctivae in insect vectors and anatomic locations related to transmission and persistence

Mycoplasma conjunctivae is an obligate microparasite that causes Infectious Keratoconjunctivitis (IKC) in Caprinae species. IKC is a long-recognised disease, but little attention has been paid to the mechanisms of transmission of the mycoplasma and its occurrence in locations other than the eyes. In this study, the presence of M. conjunctivae is assessed in the eyes, external ear canals (EEC), nasal cavity, and vagina of host species as well as in potential vectors, which may be involved in the transmission and persistence of infection within the host. M. conjunctivae was detected by qPCR in 7.2 % (CI 95% 4.7-11.0) of the ear swabs and 9.5 % (CI 95% 6.4-13.9) of the nasal swabs from Pyrenean chamois, Iberian ibex, domestic sheep and mouflon without statistical differences between species. Mycoplasma detection in nasal swabs was mostly associated with ocular infection (95.6%), but this was not the case for EEC (52.6%). Among the eye-positive ruminants, 27.3% were positive in ear swabs and 64.7% in nasal swabs, and the threshold cycle values of the qPCR were correlated only between eye and nasal swabs (p < 0.01; r₂ = 0.56). M. conjunctivae was detected in 1.7% - 7.1 % of Musca spp. captured during an IKC outbreak in Iberian ibex and in one out of three endemic sheep flocks. The results indicate that the transmission of M. conjunctivae may occur by direct contact with eye or nasal secretions and/or indirectly through flies. The M. conjunctivae DNA detection in EEC suggests that it can colonise the auditory tract, but the significance for its persistence within the host should be further assessed.

Field trials of fatty acids and geraniol applied to cattle for suppression of horn flies, Haematobia irritans (Diptera: Muscidae), with observations on fly defensive behaviors

Adult horn fly populations were tracked on cattle for 2-week periods before, during and after multiple treatments (every 3-4days) with two repellents in a mineral oil carrier. Cattle were sprayed four times in a two-week period either with 2% geraniol (125ml/cow) or a 15% mixture of short chain fatty acids (C8-C9-C10)(250ml/cow), and there were untreated control cattle. Trials were conducted in California and North Carolina for 3 summers. Short-term fly counts (same day) on treated cattle were reduced by 61-99%, depending on material and trial, and the fatty acid mixture provided better control than geraniol. Horn fly counts were suppressed for 1-3 d and rebounded somewhat after both treatments. Consecutive treatments showed evidence of persistent impact in California where herds were more isolated. Rebounds to pre-treatment levels 3-4 d after treatment occurred more often in North Carolina, where other infested cattle were closer to treated herds. By 3-4 d post-treatment, horn flies were reduced by 29-61% in California and 0-83% in North Carolina, relative to pre-treatment. Background behavior frequencies were assessed from hundreds of counts on untreated, infested California cattle, where horn flies were the only abundant biting fly. Behavior averages were 16.5 tail flicks, 7.6 skin twitches, 1.2 head throws, or 0.2 leg stamps per 2min observation period. At horn fly densities from about 200 to more than 1000 flies per animal (moderate to high numbers), fly defensive behaviors on control cattle were poorly related (or unrelated) to fly numbers. Immediately after repellent application, however, flies were almost absent and behavior frequencies dropped distinctly. Cattle fly defensive behaviors therefore seem to be quite sensitive to low (less than 100 flies/animal) horn fly densities, and behaviors would be a poor quantitative tool to track fly stress at moderate densities and above. Both geraniol and the fatty acids show promise for horn fly control, especially in organic agriculture. Treatments at 1-2 d intervals probably would keep infestations below the economic threshold (200 flies/cow).

Species Abundance and Identification of Forensically Important Flies of Saudi Arabia by DNA Barcoding

Because they may demonstrate characteristics of the environment where a body has been laying prior to the discovery, flies are insects of forensic interest. We investigated the fly abundance and the effect of location in Kingdom of Saudi Arabia on fly species diversity that attack decomposing human and animal remains. Using baited traps deployed in each location, we collected 3,697 flies of seven species belonging to three families. Chrysomya albiceps Wiedmann represented 60.86% of the collected flies, whereas Musca domestica L. represented 25.8%; the other species made up < 6% each. To facilitate species identification by DNA barcoding, we sequenced a 710-bp "Folmer region" of cytochrome oxidase subunit 1 (COI) gene for 22 samples from collection sites distributed through entire Saudi Arabia. The COI sequences from Musca albina Wiedmann, Musca lucidula Loew, Musca calleva Walker, Musca sorbens Wiedmann, and Physiphora alceae Preyssler were obtained for the first time. This primary study indicates that even when Folmer primers were widely used in DNA barcoding, the Folmer's region is not adequate when discriminating between Musca species, and sequencing the whole COI or other genes is required for forensic purpose.

Glia-related circadian plasticity in the visual system of Diptera

The circadian changes in morphology of the first visual neuropil or lamina of Diptera represent an example of the neuronal plasticity controlled by the circadian clock (circadian plasticity). It is observed in terminals of the compound eye photoreceptor cells, the peripheral oscillators expressing the clock genes. However, it has been found also in their postsynaptic partners, the L1 and L2 monopolar cells, in which the activity of the clock genes have not yet been detected. The circadian input that the L1 and L2 receive seems to originate not only from the retina photoreceptors and from the circadian pacemaker neurons located in the brain, but also from the glial cells that express the clock genes and thus contain circadian oscillators. This paper summarizes the morphological and biochemical rhythms in glia of the optic lobe, shows how they contribute to circadian plasticity, and discusses how glial clocks may modulate circadian rhythms in the lamina.

Virology, Epidemiology and Pathology of Glossina Hytrosavirus, and Its Control Prospects in Laboratory Colonies of the Tsetse Fly, Glossina pallidipes (Diptera; Glossinidae)

The Glossina hytrosavirus (family Hytrosaviridae) is a double-stranded DNA virus with rod-shaped, enveloped virions. Its 190 kbp genome encodes 160 putative open reading frames. The virus replicates in the nucleus, and acquires a fragile envelope in the cell cytoplasm. Glossina hytrosavirus was first isolated from hypertrophied salivary glands of the tsetse fly, Glossina pallidipes Austen (Diptera; Glossinidae) collected in Kenya in 1986. A certain proportion of laboratory G. pallidipes flies infected by Glossina hytrosavirus develop hypertrophied salivary glands and midgut epithelial cells, gonadal anomalies and distorted sex-ratios associated with reduced insemination rates, fecundity and lifespan. These symptoms are rare in wild tsetse populations. In East Africa, G. pallidipes is one of the most important vectors of African trypanosomosis, a debilitating zoonotic disease that afflicts 37 sub-Saharan African countries. There is a large arsenal of control tactics available to manage tsetse flies and the disease they transmit. The sterile insect technique (SIT) is a robust control tactic that has shown to be effective in eradicating tsetse populations when integrated with other control tactics in an area-wide integrated approach. The SIT requires production of sterile male flies in large production facilities. To supply sufficient numbers of sterile males for the SIT component against G. pallidipes, strategies have to be developed that enable the management of the Glossina hytrosavirus in the colonies. This review provides a historic chronology of the emergence and biogeography of Glossina hytrosavirus, and includes researches on the infectomics (defined here as the functional and structural genomics and proteomics) and pathobiology of the virus. Standard operation procedures for viral management in tsetse mass-rearing facilities are proposed and a future outlook is sketched.

Natural occurrence of entomogenous nematodes in tennessee nursery soils

To isolate potential insect biocontrol agents, entomogenous nematodes were surveyed in Tennessee plant nurseries in 1991. Soil samples from 113 nursery sites were baited with greater wax moth (Galleria mellonella) larvae, house cricket (Acheta domesticus) adults, lesser mealworm (Alphitobius diaperings) adults, and house fly (Musca domestica) larvae. Heterorhabditis bacteriophora and Steinernema carpocapsae were each recovered from 17 soil samples. Heterorhabditis bacteriophora was more common in habitats with crape myrtle (Lagerstroemia indica) and Chinese juniper (Juniperus chinensis) than other nursery plants, and S. carpocapsae was more frequently recovered from habitats with juniper and Southern magnolia (Magnolia grandiflora). Bulk density, electrical conductivity, organic matter, pH, temperature, and moisture content of the entomogenous-nematode positive soil samples were compared. Other nematode genera recovered with insect baits included Rhabditis sp., Pelodera sp., Cryptaphelenchoides sp., and Mesodiplogaster sp., which was recovered from a greater percentage of soil samples than the other five genera.