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.

A new species of Sumapazomyia Fogaa, Couri, Prez & de Carvalho (Diptera: Muscidae) from Colombia.

Sumapazomyia Fogaa et al. 2019, is a monotypic Andean genus from the Colombian Andes. Here we described one new species of Sumapazomyia from Colombia, namely Sumapazomyia quimbaya sp. nov. (type-locality: Risaralda, Otn, Quimbaya, Santuario de Fauna y Flora Otn Quimbaya), and an identification key to segregate the two species, including color images and illustrations of male and female terminalia is given. The distribution of the two species is mapped.

Evaluation of mechanical transmission of Trypanosoma vivax by Stomoxys calcitrans in a region without a cyclic vector.

This work investigated the mechanical transmission of Trypanosoma vivax by Stomoxys calcitrans to cattle in a region without a cyclic vector. The study involved two experiments, one with calves experimentally infected with T. vivax, in the acute phase of trypanosomosis (Experiment 1) and the other in the chronic phase (Experiment 2). In both experiments, two transmission methods were used with flies that had not fed for 24 h or had never fed: (i) Method 1: flies released freely in cattle pens (≈3,300 flies/pen for 10 days); and (ii) Method 2: flies placed in a feeding chamber (12 flies/animal). To develop Method 1 in the two experiments (acute and chronic phases), T. vivax-positive animals were kept with T. vivax-negative animals. Periodically, the Brener method, Woo method, blood smears, cPCR, ELISA, IFAT, and Imunoteste® were performed to detect T. vivax in the animals. We also recorded the animals' head tossing and hoof stomping and the number of flies near the pens' inner walls. Subsequently, biological testing was performed using lambs. For Method 2 in both experiments, flies inside the feeding chamber first fed on T. vivax-positive animals and later on negative animals. In both experiments and methods, we examined the flies for the presence of T. vivax through blood smears and cPCR of the proboscis and abdomen. In Experiment 2 (chronic phase), a test was conducted to determine how long trypomastigotes forms could survive on the blood of animals with different levels of parasitemia. None of the animals (calves and lambs) became infected with T. vivax or showed antibodies against it. During the evaluation period, the animals in the presence of the flies exhibited more hoof stomping and head tossing compared to those without flies (control). Additionally, there was an increase in the number of flies in the pens during the experiment. Only in Experiment 1 (acute phase) were T. vivax trypomastigotes and DNA found in the abdomen of the flies but not in the proboscis. In Experiment 2 (chronic phase), higher concentrations of trypomastigotes per milliliter of blood were associated with a shorter the lifespan of this stage of the parasite. In conclusion, under the variable conditions of the experiments (hosts, number of flies, and level of parasitemia), S. calcitrans was unable to mechanically transmit T. vivax to cattle.

Urban living can rescue Darwin's finches from the lethal effects of invasive vampire flies.

Human activity changes multiple factors in the environment, which can have positive or negative synergistic effects on organisms. However, few studies have explored the causal effects of multiple anthropogenic factors, such as urbanization and invasive species, on animals and the mechanisms that mediate these interactions. This study examines the influence of urbanization on the detrimental effect of invasive avian vampire flies (Philornis downsi) on endemic Darwin's finches in the Galápagos Islands. We experimentally manipulated nest fly abundance in urban and non-urban locations and then characterized nestling health, fledging success, diet, and gene expression patterns related to host defense. Fledging success of non-parasitized nestlings from urban (79%) and non-urban (75%) nests did not differ significantly. However, parasitized, non-urban nestlings lost more blood, and fewer nestlings survived (8%) compared to urban nestlings (50%). Stable isotopic values (δ15 N) from urban nestling feces were higher than those from non-urban nestlings, suggesting that urban nestlings are consuming more protein. δ15 N values correlated negatively with parasite abundance, which suggests that diet might influence host defenses (e.g., tolerance and resistance). Parasitized, urban nestlings differentially expressed genes within pathways associated with red blood cell production (tolerance) and pro-inflammatory response (innate immunological resistance), compared to parasitized, non-urban nestlings. In contrast, parasitized non-urban nestlings differentially expressed genes within pathways associated with immunoglobulin production (adaptive immunological resistance). Our results suggest that urban nestlings are investing more in pro-inflammatory responses to resist parasites but also recovering more blood cells to tolerate blood loss. Although non-urban nestlings are mounting an adaptive immune response, it is likely a last effort by the immune system rather than an effective defense against avian vampire flies since few nestlings survived.

Characterization of intrapuparial development of Musca domestica (Diptera: Muscidae), under different temperatures in laboratory conditions.

Musca domestica (Linnaeus, 1758) (Diptera: Muscidae), popularly known as "housefly", is a highly synanthropic species, with economic, medical-sanitary, veterinary, and forensic importance. It is able to cause damage to health, transmit pathogenic agents, cause infection in domestic animals, and, in its immature stage, cause secondary myiasis. The scavenging habit of its immature stages makes these flies pioneers in colonizing both human and animal carcasses, from the initial stages of corpse decomposition to the final stages. Intrapuparial development studies of all stages of the biological cycle of these insects help estimate pupal age, being useful to forensic entomology to aid in determining the minimum postmortem interval (minPMI). This study describes, morphologically, the external structures of the pupae, under temperatures of 23, 27, and 30 ±â€…1 °C aiming to identify the characteristics that define their developmental stages and estimation of the pupae age of M. domestica. The whole experiment was carried out under laboratory conditions, with relative humidity 60 ±â€…10% and 12 hours of photoperiod. The process of pupariation and pupation including pre-pupae phases were observed; larvae pupae apolysis; early cryptocephalic pupae; late cryptocephalic pupae; phanerocephalic pupae; pharate adult, discriminated by eye color (transparent eyes, pink eyes, and red eyes); and the emergency of adults, which occurred in the intervals of 162-180; 138-144, and 96-102 hr, respectively, being described throughout the metamorphosis of the external morphological characteristics of the pupal stage of M. domestica.

First report of the efficacy of a fluralaner-based pour-on product (Exzolt® 5%) against ectoparasites infesting cattle in Brazil.

BACKGROUND: This study describes the effectiveness of a novel active pharmaceutical ingredient, fluralaner (isoxazoline class), against important ectoparasites infesting cattle in Brazil. METHODS: A total of 13 studies involving a 5% fluralaner-based pour-on formulation (Exzolt 5%; further referred to as Exzolt) were conducted. Specifically, the effectiveness of this formulation was studied against Rhipicephalus microplus (6 studies), Cochliomyia hominivorax larvae (4 studies), Dermatobia hominis larvae (1 study) and Haematobia irritans flies (2 studies). RESULTS: The therapeutic efficacy of Exzolt was found to exceed 98% at 4 days post treatment (DPT), while persistent efficacy (> 90% efficacy) against repeated infestations of R. microplus was observed for up to 79 DPT. In field studies, ≥ 98% therapeutic efficacy was demonstrated at all study sites by 7 DPT, and a persistent efficacy (> 90% efficacy) was observed for 42, 49 or 56 DPT. Exzolt prevented C. hominivorax eggs from developing to the larval stage, thus mitigating the development of myiasis in cattle naturally and artificially infested with this screworm. The efficacy of Exzolt against D. hominis larvae was 98% at 3 DPT, while persistent efficacy (> 90% effectiveness) was found to last for up to 70 DPT. Against H. irritans, Exzolt showed therapeutic efficacy (≥ 90%) within the first day of treatment at both study sites, while persistent efficacy (≥ 90%) was observed for 7 DPT at one site and for 21 DPT at the other site. CONCLUSIONS: Overall, the results from these studies confirm that Exzolt is therapeutically efficacious against the most important ectoparasites infesting cattle in Brazil. The novel active pharmaceutical ingredient, fluralaner, provides a new treatment option for farmers to control cattle ectoparasites, especially where there is resistance to other chemical classes. In addition, an effective control of ectoparasites will improve overall cattle health and well-being as well as production.

Fannia pretiosa-group (Diptera: Fanniidae) from Mexico: six new species from the Mexico Transition Zone and an identification key.

Fannia Robineau-Desvoidy is found in all biogeographic regions. The genus contains approximately 360 known species, 18 of which have been recorded from Mexico. Herein, we describe six new species in the Fannia pretiosa-group, redescribe Fannia gilvitarsis Chillcott, and provide diagnosis, habitus images, drawings of the male terminalia, and an identification key for all species of the group that occur in Mexico. All Fannia pretiosa-group species from Mexico share a similar morphology of the mid tibia, hind femur, and male terminalia.

Evaluation in vitro of the virulence of two entomopathogenic heterorhabditid nematodes in the control of Stomoxys calcitrans (Diptera: Muscidae) larvae in byproducts of the sugar and alcohol industry.

Stomoxys calcitrans causes losses to livestock, mainly to cattle. This study aimed to determine the pathogenic potential of Heterorhabditis bacteriophora HP88 and H. baujardi LPP7 against S. calcitrans larvae after being exposed to byproducts of the sugar and alcohol industry. The efficacy of EPNs on stable fly larvae was evaluated in bioassays with vinasse at three temperatures (16, 25 and 35 °C) and concentrations (0, 50 and 100%), as well as in relation to larva age (4, 6 and 8 days) in filter cake and EPNs concentration (100, 300 and 500 IJs/larva) in sugarcane bagasse. H. bacteriophora showed higher efficacy than H. baujardi at all temperatures. Vinasse did not have a negative effect on the virulence of H. bacteriophora. The age of fly larvae did not affect the mortality rates caused by the EPNs. In bagasse, H. bacteriophora presented higher mortality rates than the control group. It is concluded that EPNs can be a potential component in integrated strategies of stable fly control and outbreak prevention in areas of sugar and alcohol production.

Stable fly outbreaks in Brazil: a 50-year (1971-2020) retrospective.

Over the last decades, stable fly (Stomoxys calcitrans) outbreaks associated with agricultural and/or livestock production systems have become a serious problem in some Brazilian locations. This article presents a survey on the history, evolution and mapping of such outbreaks in Brazil over five decades (1971-2020). Outbreaks (n= 579) were recorded in 285 municipalities from 14 states, mainly associated with by-products from the ethanol industry (82.7%), in natura organic fertilizers (12.6%) and integrated crop-livestock systems (3.1%). Few cases were reported until the mid-2000s, progressively increasing since then. Outbreaks associated with ethanol mills occurred in 224 municipalities, mainly in Southeast and Midwest states, while those associated with organic fertilizers (mainly poultry litter and coffee mulch) affected 39 municipalities, mostly in the Northeast and Southeast states. More recently, outbreaks in integrated crop-livestock systems during the rainy season have occurred in Midwest states. This survey highlights the magnitude of the problem of stable fly outbreaks in Brazil and its relationship with environmental public policies, agricultural production chains and regional trends. Specific public actions and policies are urgently needed to prevent their occurrence and impact in the affected regions.

Sarcosaprophagous Muscid Fly (Diptera: Muscidae) Assemblages Along an Anthropized Gradient in the Humid Chaco Ecoregion, Chaco Province, Argentina.

Deforestation, agriculture, farmyard animal husbandry, and urbanization are known to be the main causes of biodiversity loss and habitat fragmentation. The present study evaluated the role of anthropization in modulating Muscidae (Diptera) assemblages in the Humid Chaco ecoregion of Argentina, by testing the biotic homogenization and intermediate disturbance hypotheses. The study focused on natural, rural, and urban habitats in San Lorenzo Department, Chaco Province, where sarcosaprophagous muscid flies were surveyed. A total of 1,343 muscid flies were captured and identified to 7 genera and 24 species and morphospecies. We observed the effect of anthropization on the structuring of the assemblages and the presence of exotic species associated with human activity resulting from biotic homogenization. The highest abundance was recorded in the urban habitat, while the highest species richness and diversity (Shannon-Wienner and Hill's numbers) were found in the rural habitat, supporting the intermediate disturbance hypothesis. Several species are classified as indicators of habitat as well as according to their index of synanthropy. Our results provide valuable information about the use of sarcosaprophagous muscids as indicators of disturbance of natural habitats and about possible health risks related to this family of Calyptratae flies previously unsurveyed in northeastern Argentina. This information could be used in the ecological, agronomy, sanitary, and forensic fields.

First record of Trypanosoma evansi DNA in Dichelacera alcicornis and Dichelacera januarii (Diptera: Tabanidae) flies in South America.

BACKGROUND: Trypanosoma evansi infects a large number of wild and domestic animals and causes a spoliative disease known as surra. It is mechanically transmitted, mainly by biting flies of the genera Tabanus and Stomoxys. The detection of T. evansi DNA in the feeding apparatus of Dichelacera alcicornis and Dichelacera januarii from South America is reported, to the best of our knowledge, for the first time. METHODS: Tabanids were collected weekly from February 2018 to February 2019 from two sites. The feeding apparatus was removed and DNA extraction, polymerase chain reaction and sequencing were performed. RESULTS: A 205-base pair fragment of the variant surface protein RoTat 1.2 gene, confirmed by DNA sequencing, was amplified from the feeding apparatus of D. alcicornis and D. januarii. CONCLUSIONS: This is, to the best of our knowledge, the first record of T. evansi DNA in South American tabanids.

Stable fly outbreaks in Brazil: a 50-year (1971-2020) retrospective / Surtos da mosca-dos-estábulos no Brasil: Retrospectiva 50 anos (1971-2020)

Over the last decades, stable fly (Stomoxys calcitrans) outbreaks associated with agricultural and/or livestock production systems have become a serious problem in some Brazilian locations. This article presents a survey on the history, evolution and mapping of such outbreaks in Brazil over five decades (1971-2020). Outbreaks (n= 579) were recorded in 285 municipalities from 14 states, mainly associated with by-products from the ethanol industry (82.7%), in natura organic fertilizers (12.6%) and integrated crop-livestock systems (3.1%). Few cases were reported until the mid-2000s, progressively increasing since then. Outbreaks associated with ethanol mills occurred in 224 municipalities, mainly in Southeast and Midwest states, while those associated with organic fertilizers (mainly poultry litter and coffee mulch) affected 39 municipalities, mostly in the Northeast and Southeast states. More recently, outbreaks in integrated crop-livestock systems during the rainy season have occurred in Midwest states. This survey highlights the magnitude of the problem of stable fly outbreaks in Brazil and its relationship with environmental public policies, agricultural production chains and regional trends. Specific public actions and policies are urgently needed to prevent their occurrence and impact in the affected regions.(AU)

Nas últimas décadas, surtos da mosca-dos-estábulos (Stomoxys calcitrans), associados a sistemas de produção agrícola e/ou pecuária, tornaram-se um grave problema em algumas localidades brasileiras. Este artigo apresenta um levantamento sobre a história, evolução e mapeamento desses surtos no Brasil ao longo de cinco décadas (1971-2020). Surtos (n= 579) foram registrados em 285 municípios de 14 estados, principalmente associados a subprodutos da indústria do etanol (82,7%), fertilizantes orgânicos in natura (12,6%) e sistemas de integração lavoura-pecuária (3,1%). Poucos casos foram registrados até meados dos anos 2000, aumentando progressivamente desde então. Surtos associados a usinas de etanol ocorreram em 224 municípios, principalmente no Sudeste e Centro-Oeste, enquanto surtos associados a fertilizantes orgânicos (principalmente esterco aviário e palha de café) afetaram 39 municípios, principalmente nos estados do Nordeste e Sudeste. Mais recentemente, surtos em sistemas de integração lavoura-pecuária, durante a estação chuvosa, têm ocorrido no Centro-Oeste. Este levantamento ressalta a magnitude do problema dos surtos da mosca-dos-estábulos no Brasil e sua relação com políticas públicas ambientais, cadeias produtivas agrícolas e tendências regionais. Ações e políticas públicas específicas são urgentemente necessárias para prevenir sua ocorrência e impacto nas regiões afetadas.(AU)

Evaluation in vitro of the virulence of two entomopathogenic heterorhabditid nematodes in the control of Stomoxys calcitrans (Diptera: Muscidae) larvae in byproducts of the sugar and alcohol industry / Avaliação in vitro da virulência de dois nematoides entomopatogênicos heterorhabditídeos no controle de larvas de Stomoxys calcitrans (Diptera: Muscidae) em subprodutos da indústria sucroalcooleira

Stomoxys calcitrans causes losses to livestock, mainly to cattle. This study aimed to determine the pathogenic potential of Heterorhabditis bacteriophora HP88 and H. baujardi LPP7 against S. calcitrans larvae after being exposed to byproducts of the sugar and alcohol industry. The efficacy of EPNs on stable fly larvae was evaluated in bioassays with vinasse at three temperatures (16, 25 and 35 °C) and concentrations (0, 50 and 100%), as well as in relation to larva age (4, 6 and 8 days) in filter cake and EPNs concentration (100, 300 and 500 IJs/larva) in sugarcane bagasse. H. bacteriophora showed higher efficacy than H. baujardi at all temperatures. Vinasse did not have a negative effect on the virulence of H. bacteriophora. The age of fly larvae did not affect the mortality rates caused by the EPNs. In bagasse, H. bacteriophora presented higher mortality rates than the control group. It is concluded that EPNs can be a potential component in integrated strategies of stable fly control and outbreak prevention in areas of sugar and alcohol production.(AU)

Stomoxys calcitrans causa perdas à agropecuária, principalmente na bovinocultura. Este estudo objetivou verificar o potencial patogênico de Heterorhabditis bacteriophora HP88 e H. baujardi LPP7 para larvas de S. calcitrans, após serem expostos a subprodutos da indústria sucroalcooleira. A eficácia dos NEPs sobre larvas da mosca-dos-estábulos foi avaliada em bioensaios com vinhaça em três temperaturas (16, 25 e 35 °C) e concentrações (0, 50 e 100%), bem como em relação à idade da larva (4, 6 e 8 dias) em torta de filtro e concentração de NEPs (100, 300 e 500 JIs/larva) em bagaço de cana-de-açúcar. H. bacteriophora apresentou maior eficácia do que H. baujardi em todas as temperaturas. O vinhoto não apresentou efeito negativo sobre a virulência de H. bacteriophora. A idade das larvas não influenciou no aumento ou diminuição da mortalidade dos NEPs. Em bagaço de cana, H. bacteriophora apresentou taxas de mortalidade superiores à do grupo controle. Conclui-se que os NEPs podem ser um potencial componente em estratégias de controle integrado e prevenção de surtos da mosca-dos-estábulos, em áreas de produção de açúcar e álcool.(AU)

Review of the endemic Neotropical genus Agenamyia Albuquerque (Diptera: Muscidae) with the description of new species from South America.

Agenamyia Albuquerque, an endemic neotropical genus with two species, has been revised to include three new species: Agenamyia colombiana de Carvalho, Wolff & Fogaa sp. nov. from Envigado; Agenamyia maculata de Carvalho, Wolff & Fogaa sp. nov. from El Retiro; and Agenamyia timida de Carvalho, Wolff & Fogaa sp. nov. from Sopetrn, all localities in Antioquia, Colombia. This review presents an identification key for all species, including color images and illustrations of male and female terminalia. The distribution of all species is mapped and discussed.

Global genomic methylation related to the degree of parasitism in cattle.

The objective of the present study was to characterize a herd of 72 ½ Angus × ½ Nellore heifers, identify the resistant, resilient and susceptible animals to parasites, relate the overall DNA methylation of these animals with the degree of parasitism, evaluated by the egg count per gram of feces (EPG), Haematobia irritans count (horn fly) and Rhipicephalus microplus count (bovine tick). The experiment was carried out in a completely randomized design, containing 72 treatments, with each animal considered a treatment, and 11 repetitions, with each collection within a year considered a repetition. The data obtained from the counts of the evaluated parasites were subjected to statistical analysis using the SISVAR program, to classify heifers according to the degree of parasitism in low (resistant), intermediary (resilient) and high (susceptible) parasite load for infection by nematodes, infestation by ticks and flies. Addition the animals in these three groups, by hierarchical grouping using the GENES program, heifers were classified as to the degree of parasitism by the three parasites along with the DNA methylation content of the animals in each group. A negative relationship was observed between resistance and methylated DNA content in both classifications, with the resistant, resilient, and susceptible animals showing the highest, intermediate, and lowest methylated DNA quantifications, respectively. Thus, the methodologies used herein enabled the classification of 72 heifers according to the degree of collective infection by gastrointestinal nematodes and infestation by ticks and horn flies, thereby establishing a link between the degree of parasitic resistance in cattle and the global methylated DNA quantification.

Development and Intrapuparial Characterization of Hydrotaea aenescens (Diptera: Muscidae) Raised at Different Temperatures Under Laboratory Conditions.

Species belonging to the Muscidae family are important in the medical-sanitary and forensic fields due to their biology. The intrapuparial stage of Hydrotaea aenescens (Wiedemann, 1830), which represents about 50% of the immature development cycle in muscoid Diptera, has not yet been studied in detail. This study identifies and describes the main temporal morphological changes that occur in the pupal body of H. aenescens during its development at 22, 27, and 32 ± 1°C, RH 60 ± 10% with a 12-hr photoperiod. Ten pupae were collected, sacrificed, and fixed every 3 hr after pupariation up to 24 hr, and every 6 hr thereafter until the first emergence. Emergence took place at 282, 174, and 126 hr at 22, 27, and 32°C, with 520, 340, and 260 pupae, respectively. External morphology was described and recorded at eight development stages: pupariation, pre-pupae, early and late cryptocephalic pupae, phanerocephalic pupae, pupae-adult apolysis, pharate adults, and imago, employing 18 key morphological characters for pupae age. These morphological pupae characters, comprise, therefore an alternative and/or additional method to aid in determining the minimum Postmortem Interval (minPMI).

Macrocyclic lactone resistance in nematodes of cattle in Brazil: Blame it to the ticks!

Strategic helminth control in adult cattle would hardly impose sufficient selection pressure to parasite populations but reports of resistance against macrocyclic lactone (ML) based-products have been confirmed worldwide. The objective of this study was to evaluate the scientific literature of ML resistance (< 90.0% efficiency) in helminths of cattle from 2001 (the first report) to 2020 in Brazil. Additional to the data, we studied the correlation of parasite control practices based on a questionnaire given to 32 farmers. The search returned 246 reports and 21 full articles were selected. From these, a Wordcloud and a Keyword Co-occurrence Network graph were created. The published data revealed that most of the studies (19/21) reported multi-species (Cooperia spp., Haemonchus sp., Oesophagostomum radiatum, Trichostrongylus sp.) resistance to ML. None of the reports described the treatment frequency in the tested farms. As for the questionnaire, the majority of farmers (> 70.0%) responded that they rotate products after treatment, animals are treated monthly or biweekly (58.0%), treatments are based on visual evaluation (coat condition, ectoparasite infestation), and that in 94.0% of the times farmers treat all animals. Moreover, farmers use ML in association with potent acaricides (cypermethrin, chlorpyriphos, fluazuron) in more than 90.0% of the times (15/16). It was observed that this regimen was used to prevent and control the cattle-tick Rhipicephalus microplus (90.0%) and the horn-fly, Haematobia irritans (30.0%) infestations. We conclude that the most important factor for nematode resistance was the high level of ML exposure of up to 16 times/year, in combination with acaricides to control ticks and to a lesser extent to control horn-flies. Therefore, selection of helminth populations in cattle in Brazil can be considered secondary to ectoparasite control. The present analysis is critical, as one the most widespread recommendations to avoid drug resistance is to reduce the use of long-acting compounds, due to their extended persistent periods, increasing parasite selection. Moreover, a more serious attitude must be taken regarding parasite control strategies for livestock, reinforcing that health protocols should be based on single acaricidal products whenever possible. Complementary, selective evaluations based on transient threshold population abundance must be enforced to reduce treatment frequency, reducing parasite selection and animal distress.

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.

The genome sequence of the avian vampire fly (Philornis downsi), an invasive nest parasite of Darwin's finches in Galápagos.

The invasive avian vampire fly (Philornis downsi, Diptera: Muscidae) is considered one of the greatest threats to the endemic avifauna of the Galápagos Islands. The fly larvae parasitize nearly every passerine species, including Darwin's finches. Most P. downsi research to date has focused on the effects of the fly on avian host fitness and mitigation methods. A lag in research related to the genetics of this invasion demonstrates, in part, the need to develop full-scale genomic resources with which to address further questions within this system. In this study, an adult female P. downsi was sequenced to generate a high-quality genome assembly. We examined various features of the genome (e.g., coding regions and noncoding transposable elements) and carried out comparative genomics analysis against other dipteran genomes. We identified lists of gene families that are significantly expanding or contracting in P. downsi that are related to insecticide resistance, detoxification, and counter defense against host immune responses. The P. downsi genome assembly provides an important resource for studying the molecular basis of successful invasion in the Galápagos and the dynamics of its population across multiple islands. The findings of significantly changing gene families associated with insecticide resistance and immune responses highlight the need for further investigations into the role of different gene families in aiding the fly's successful invasion. Furthermore, this genomic resource provides a necessary tool to better inform future research studies and mitigation strategies aimed at minimizing the fly's impact on Galápagos birds.

Semi-field evaluation of the predation of Macrocheles embersoni and Macrocheles muscaedomesticae (Acari: Mesostigmata: Macrochelidae) on the house fly and the stable fly (Diptera: Muscidae).

BACKGROUND: The house fly, Musca domestica L., and the stable fly, Stomoxys calcitrans (L.), are important and harmful organisms. The cosmopolitan house fly is not parasitic, but the adults are annoying and a known vector of several pathogens. The importance of the stable fly has increased in Brazil in the last 40 years, after major changes in sugarcane cultivation practices were implemented, including the widespread application of vinasse (byproduct in sugarcane mills) and the parallel reduction of sugarcane preharvest burning. These changes have favored the development of this fly, which can reach high populations, that can negatively affect cattle and other animals. The control of these flies relies heavily on the use of chemical products, which very often do not provide adequate population reduction. Predatory mites of the family Macrochelidae have been evaluated under laboratory conditions for the biological control of these organisms, especially of the house fly. The objective of this study was to examine the predation capacity of the macrochelids Macrocheles embersoni Azevedo, Castilho & Berto and Macrocheles muscaedomesticae (Scopoli) on the house fly and the stable fly, under semi-field conditions (screen-houses). RESULTS: Reductions of 83 to 90% of the house fly and 66 to 73% of the stable fly populations were observed, with the release of 100 of these predators per square meter. CONCLUSIONS: The number of adults of both fly species was much lower in the units where the predators had been released than in the others. However it is suggested that provisioning and or conserving alternative food sources for these macrochelids, such as free-living nematodes, could further improve biocontrol efficacy.