Drosophilid Flies Research Articles

AN ANNOTATED LIST OF FRUIT FLIES (DIPTERA: DROSOPHILIDAE) OF THE REPUBLIC OF MORDOVIA

An annotated list of 44 species in 12 genera of the drosophilid flies of the Republic of Mordovia is given. Among them Drosophila picta Ztt. is recorded in Russia for the first time, D. bondarenkoi Sidorenko is found in European Russia for the first time and 8 species are new to the fauna of the Republic of Mordovia. The drosophilid fauna of Mordovia is compared with Voronezhskaya oblast.

New host record of Thelazia callipaeda (Nematoda: Spirurida) with a notably wide host range and shared zoonotic lineage in Japan

Thelazia callipaeda (Nematoda: Spirurida: Thelaziidae) parasitizes the eyes of dogs, cats, humans, and various wild mammals, and is transmitted by drosophilid flies. In Japan, T. callipaeda is considered an emerging parasite that has expanded its endemic region northward. However, reports of its detection in mammals other than domestic animals and humans are scarce. This study reports the detection of T. callipaeda in Japanese red fox (Vulpes vulpes japonica), masked palm civet (Paguma larvata), Japanese badger (Meles anakuma), Japanese black bear (Ursus thibetanus japonicus), raccoon (Procyon lotor), Japanese raccoon dog (Nyctereutes viverrinus), domestic dog (Canis lupus familiaris), domestic cat (Felis silvestris catus), and human. Of these, the Japanese red fox, masked palm civet, Japanese badger, and Japanese black bear have been reported as novel host records. Sequence analysis of the cytochrome c oxidase subunit I gene of T. callipaeda revealed two unique lineages specific to Japan, with no regional or host species differences. These results suggest a wide host range for T. callipaeda, highlighting the significant role of wildlife as a reservoir for this parasite in Japan.

Attractant spray enhances nesting preference and reduces macroparasite infestation of Osmia cornuta

AbstractMason bees (Osmia. spp) can provide an alternative for crop pollination management in addition to the Western honeybees (Apis mellifera). Targeted evidence‐based guidelines can improve cost‐effective management of mason bees. Here, I test the effect of an attractant spray developed in the United States for improving the nesting preference for artificial trap nests of mason bees in Belgium. More specifically, this study investigates the effect of the attractant spray on the nesting preference and nesting performance of the European orchard bee (Osmia cornuta), as well as its effect on the infestation of nest‐associated macroparasites. The number of sealed nesting cavities was twice as high in the trap nests that were treated with the attractant spray. Nesting performance expressed as number of brood cells per cavity, successful cocoon formation, adult emergence, proportion of female bees in the offspring and the number of dead larvae was not different between the treated and the untreated nests. Overall infestation of macroparasites, and infestation of drosophilid flies in particular, were both twice as high in untreated nests. This study provides evidence that the attractant spray improves nesting preference and reduces macroparasite infestation in O. cornuta. The use of this attractant can provide growers and stakeholders with an effective management strategy to prevent infestation by macroparasites and promote efficient bee breeding.

Chemical imitation of yeast fermentation by the drosophilid-pollinated deceptive trap-flower Aristolochia baetica (Aristolochiaceae)

Deceptive flowers, unlike in mutualistic pollination systems, mislead their pollinators by advertising rewards which ultimately are not provided. Although our understanding of deceptive pollination systems increased in recent years, the attractive signals and deceptive strategies in the majority of species remain unknown. This is also true for the genus Aristolochia, famous for its deceptive and fly-pollinated trap flowers. Representatives of this genus were generally assumed to be oviposition-site mimics, imitating vertebrate carrion or mushrooms. However, recent studies found a broader spectrum of strategies, including kleptomyiophily and imitation of invertebrate carrion. A different deceptive strategy is presented here for the western Mediterranean Aristolochia baetica L. We found that this species is mostly pollinated by drosophilid flies (Drosophilidae, mostly Drosophila spp.), which typically feed on fermenting fruit infested by yeasts. The flowers of A. baetica emitted mostly typical yeast volatiles, predominantly the aliphatic compounds acetoin and 2,3-butandiol, and derived acetates, as well as the aromatic compound 2-phenylethanol. Analyses of the absolute configurations of the chiral volatiles revealed weakly (acetoin, 2,3-butanediol) to strongly (mono- and diacetates) biased stereoisomer-ratios. Electrophysiological (GC-EAD) experiments and lab bioassays demonstrated that most of the floral volatiles, although not all stereoisomers of chiral compounds, were physiologically active and attractive in drosophilid pollinators; a synthetic mixture thereof successfully attracted them in field and lab bioassays. We conclude that A. baetica chemically mimics yeast fermentation to deceive its pollinators. This deceptive strategy (scent chemistry, pollinators, trapping function) is also known from more distantly related plants, such as Arum palaestinum Boiss. (Araceae) and Ceropegia spp. (Apocynaceae), suggesting convergent evolution. In contrast to other studies working on floral scents in plants imitating breeding sites, the present study considered the absolute configuration of chiral compounds.

Elevated ozone disrupts mating boundaries in drosophilid flies

Animals employ different strategies to establish mating boundaries between closely related species, with sex pheromones often playing a crucial role in identifying conspecific mates. Many of these pheromones have carbon-carbon double bonds, making them vulnerable to oxidation by certain atmospheric oxidant pollutants, including ozone. Here, we investigate whether increased ozone compromises species boundaries in drosophilid flies. We show that short-term exposure to increased levels of ozone degrades pheromones of Drosophila melanogaster, D. simulans, D. mauritiana, as well as D. sechellia, and induces hybridization between some of these species. As many of the resulting hybrids are sterile, this could result in local population declines. However, hybridization between D. simulans and D. mauritiana as well as D. simulans and D. sechellia results in fertile hybrids, of which some female hybrids are even more attractive to the males of the parental species. Our experimental findings indicate that ozone pollution could potentially induce breakdown of species boundaries in insects.

Extracellular freezing induces a permeability transition in the inner membrane of muscle mitochondria of freeze-sensitive but not freeze-tolerant Chymomyza costata larvae.

Background: Many insect species have evolved the ability to survive extracellular freezing. The search for the underlying principles of their natural freeze tolerance remains hampered by our poor understanding of the mechanistic nature of freezing damage itself. Objectives: Here, in search of potential primary cellular targets of freezing damage, we compared mitochondrial responses (changes in morphology and physical integrity, respiratory chain protein functionality, and mitochondrial inner membrane (IMM) permeability) in freeze-sensitive vs. freeze-tolerant phenotypes of the larvae of the drosophilid fly, Chymomyza costata. Methods: Larvae were exposed to freezing stress at -30°C for 1h, which is invariably lethal for the freeze-sensitive phenotype but readily survived by the freeze-tolerant phenotype. Immediately after melting, the metabolic activity of muscle cells was assessed by the Alamar Blue assay, the morphology of muscle mitochondria was examined by transmission electron microscopy, and the functionality of the oxidative phosphorylation system was measured by Oxygraph-2K microrespirometry. Results: The muscle mitochondria of freeze-tolerant phenotype larvae remained morphologically and functionally intact after freezing stress. In contrast, most mitochondria of the freeze-sensitive phenotype were swollen, their matrix was diluted and enlarged in volume, and the structure of the IMM cristae was lost. Despite this morphological damage, the electron transfer chain proteins remained partially functional in lethally frozen larvae, still exhibiting strong responses to specific respiratory substrates and transferring electrons to oxygen. However, the coupling of electron transfer to ATP synthesis was severely impaired. Based on these results, we formulated a hypothesis linking the observed mitochondrial swelling to a sudden loss of barrier function of the IMM.

AN ANNOTATED LIST OF THE DROSOPHILID FLIES (DIPTERA: DROSOPHILIDAE) OF KRASNODARSKY KRAI

An annotated list of 33 species in 11 genera of the drosophilid flies of Krasnodarsky krai is given; among them 17 species are recorded from this region for the first time. The drosophilid fauna of Krasnodarsky krai is compared with fauna of the Republic of Adygea.

Mortality caused by extracellular freezing is associated with fragmentation of nuclear DNA in larval haemocytes of two drosophilid flies.

The great complexity of extracellular freezing stress, involving mechanical, osmotic, dehydration and chemical perturbations of the cellular milieu, hampers progress in understanding the nature of freezing injury and the mechanisms to cope with it in naturally freeze-tolerant insects. Here we show that nuclear DNA fragmentation begins to occur in larval haemocytes of two fly species, Chymomyza costata and Drosophila melanogaster, before or at the same time as the sub-zero temperature is reached that cause irreparable freezing injury and mortality in freeze-sensitive larval phenotypes. However, when larvae of the freeze-tolerant phenotype (diapausing-cold acclimated-hyperprolinemic) of C. costata were subjected to severe freezing stress in liquid nitrogen, no DNA damage was observed. Artificially increasing the proline concentration in freeze-sensitive larvae of both species by feeding them a proline-enriched diet resulted in a decrease in the proportion of nuclei with fragmented DNA during freezing stress. Our results suggest that proline accumulated in diapausing C. costata larvae during cold acclimation may contribute to the protection of nuclear DNA against fragmentation associated with freezing stress.

Vertical Distribution of Fruit Flies (Diptera: Drosophilidae) in Deciduous Forests in the Center of European Russia.

Research of Diptera in temperate forests has demonstrated uneven vertical distributions of insects. In this study, we examined the vertical distribution, seasonal fluctuations, and species diversity of Drosophilidae species in the Mordovia State Reserve. This research marks the first exploration of drosophilid vertical stratification in the European part of Russia. Using traps, we collected flies in four deciduous forest sites between early June and mid-September in 2020. A total of 27,151 individuals from 10 genera and 34 drosophilid species were identified, with 6 species from 4 genera being new to the Republic of Mordovia. Drosophila obscura Fll. and Scaptodrosophila rufifrons Lw. were the most abundant species in traps. The total highest number of drosophilid flies (10,429 individuals) was captured at a height of 1.5 m, while the lowest number (5086 individuals) was recorded at 12 m. The average number of flies was 6240 and 5387 individuals at heights of 7.5 m and 3.5 m, respectively. However, the prevalence of drosophilid numbers at the 1.5-m height was not constant during the season. We found that in the second part of July the total fly counts at heights of 7.5 m and 12 m exceeded those at 1.5 m. We have described five different types of vertical distribution of drosophilids throughout the season, which differs markedly in mycetobionts and xylosaprobionts ecological groups. Species diversity demonstrated variations across different sites and tiers during the season, with peak diversity observed in June and September.

Temperature-dependent modulation of odor-dependent behavior in three drosophilid fly species of differing thermal preference

Rapid and ongoing climate change increases global temperature, impacts feeding, and reproduction in insects. The olfaction plays an important underlying role in these behaviors in most insect species. Here, we investigated how changing temperatures affect odor detection and ensuing behavior in three drosophilid flies: Drosophila novamexicana, D. virilis and D. ezoana, species adapted to life in desert, global, and subarctic climates, respectively. Using a series of thermal preference assays, we confirmed that the three species indeed exhibit distinct temperature preferences. Next, using single sensillum recording technique, we classified olfactory sensory neurons (OSNs) present in basiconic sensilla on the antenna of the three species and thereby identified ligands for each OSN type. In a series of trap assays we proceeded to establish the behavioral valence of the best ligands and chose guaiacol, methyl salicylate and isopropyl benzoate as representatives of a repellent, attractant and neutral odor. Next, we assessed the behavioral valence of these three odors in all three species across a thermal range (10-35 °C), with flies reared at 18 °C and 25 °C. We found that both developmental and experimental temperatures affected the behavioral performance of the flies. Our study thus reveals temperature-dependent changes in odor-guided behavior in drosophilid flies.

Phylogenetic classification and palm-inflorescence anthophily of the Colocasiomyia zeylanica species group (Diptera: Drosophilidae), with descriptions of five new species.

The zeylanica group is one of the six species groups of the anthophilic genus Colocasiomyia de Meijere in the family Drosophilidae. In addition to two known species, five morphospecies have been recognized as members of this species group but left undescribed formally. In this study, species delimitation of these putatively new species was determined by barcoding of the mitochondrial COI (cytochrome c oxydase subunit I) gene and morphological comparison. Phylogenetic relationships within the genus Colocasiomyia were inferred by a cladistic analysis of 89 morphological characters. Based on the results of these analyses, we redefined the zeylanica species group and established two subgroups within it: the zeylanica subgroup comprised of C. zeylanica, C. nepalensis, C. pinangae sp. nov., C. besaris sp. nov. and C. luciphila sp. nov., and the oligochaeta subgroup of C. oligochaeta sp. nov. and C. grimaldii sp. nov. In addition, we briefly address the anthophilic habits of drosophilid flies using palm (Arecaceae) inflorescences, especially of the zeylanica group, compiling scattered collection records from the Oriental and Papuan regions.

An annotated list of the drosophilid flies (Diptera: Drosophilidae) of the Republic of Adygea

An annotated list of 31 species in ten genera of the drosophilid flies of the Republic of Adygea is given. Among them 15 species are recorded from Adygea for the first time. The drosophilid fauna of Adygea is compared with the fauna of Krasnodar Krai.

Altitudinal distribution and seasonal life cycle of drosophilid flies (Diptera: Drosophilidae) in central Japan, with reference to their biogeographic features

AbstractAltitudinal distribution and seasonal life cycle of drosophilid flies (Diptera) were studied on the southwestern slope of Mt. Higashi‐Kagonoto in Tomi and at Ishi‐no‐yu in Shiga Heights, Nagano, central Japan. Collections of flies were carried out from early spring to late autumn using traps baited with fermenting banana. Based on the present results and previous faunal reports from central Japan, major native drosophilid species collected in this study were classified into migratory (5 species), high‐altitude (6), mid‐altitude (14) and low‐altitude (14) species. The migratory species are assumed to perform extensive seasonal migration between low‐ and high‐altitude areas. Among these native species, Drosophila alpina (a high‐altitude species) and D. moriwakii (a mid‐altitude species) are assumed to pass only one generation in a year, while the others pass two or more generations. Five of the six high‐altitude species are assigned as the Palearctic elements, while four of the five migratory species and 12 of the 14 low‐altitude species are assigned as the Sino‐Japanese elements. The mid‐altitude species consist of approximately equal numbers of the Palearctic and Sino‐Japanese elements. Among the high‐altitude species, D. alpina and Hirtodrosophila makinoi are also distributed in high‐altitude areas in Hokkaido, northern Japan. The other high‐altitude species and most of the mid‐altitude species generally occur in low‐altitude areas in Hokkaido or the further north. The Sino‐Japanese elements occurring at high and mid altitudes in central Japan are also distributed at high altitudes in southern and southwestern China.

Larval nutritional-stress and tolerance to extreme temperatures in the peach fruit fly, Bactrocera zonata (Diptera: Tephritidae)

ABSTRACTWithin the factors affecting insect tolerance to extreme environmental conditions, insect nutrition, particularly of immature stages, has received insufficient attention. In the present study, we address this gap by investigating the effects of larval nutrition on heat and cold tolerance of adult Bactrocera zonata – an invasive, polyphagous fruit fly pest. We manipulated the nutritional content in the larval diet by varying the amount of added yeast (2–10% by weight), while maintaining a constant sucrose content. Adults derived from the different larval diets were tested for their tolerance to extreme heat and cold stress. Restricting the amount of yeast reduced the efficacy of the larval diet (i.e. number of pupae produced per g of diet) as well as pupal and adult fresh weight, both being significantly lower for yeast-poor diets. Additionally, yeast restriction during the larval stage (2% yeast diet) significantly reduced the amount of protein but not lipid reserves of newly emerged males and females. Adults maintained after emergence on granulated sugar and water for 10 days were significantly more tolerant to extreme heat (i.e. knock-down time at 42 oC) when reared as larvae on yeast-rich diets (8% and 10% yeast) compared to counterparts developing on a diet containing 2% yeast. Nevertheless, the composition of the larval diet did not significantly affect adult survival following acute cold stress (exposure to −3°C for 2 hrs.). These results are corroborated by previous findings on Drosophilid flies. Possible mechanisms leading to nutrition-based heat-tolerance in flies are discussed.

Drosophilid flies (Diptera: Drosophilidae) of Georgia (Sakartvelo) with new records for the country

Four genera and 12 species of drosophilid flies have been recorded during our survey in five regions of Georgia in 2021. Two genera, Amiota (Loew, 1862) and Gitona Meigen, 1830, and four species (Amiota subtusradiata Duda 1934, Drosophila busckii Coquillett 1901, D. kuntzei Duda, 1924, and Gitona distigma Meigen, 1830) represent new records for the fauna of Georgia (Sakartvelo).

Stabilization of insect cell membranes and soluble enzymes by accumulated cryoprotectants during freezing stress

Most multicellular organisms are freeze sensitive, but the ability to survive freezing of the extracellular fluids evolved in several vertebrate ectotherms, some plants, and many insects. Here, we test the coupled hypotheses that are perpetuated in the literature: that irreversible denaturation of proteins and loss of biological membrane integrity are two ultimate molecular mechanisms of freezing injury in freeze-sensitive insects and that seasonally accumulated small cryoprotective molecules (CPs) stabilize proteins and membranes against injury in freeze-tolerant insects. Using the drosophilid fly, Chymomyza costata, we show that seven different soluble enzymes exhibit no or only partial loss of activity upon lethal freezing stress applied invivo to whole freeze-sensitive larvae. In contrast, the enzymes lost activity when extracted and frozen invitro in a diluted buffer solution. This loss of activity was fully prevented by adding low concentrations of a wide array of different compounds to the buffer, including C. costata native CPs, other metabolites, bovine serum albumin (BSA), and even the biologically inert artificial compounds HistoDenz and Ficoll. Next, we show that fat body plasma membranes lose integrity when frozen invivo in freeze-sensitive but not in freeze-tolerant larvae. Freezing fat body cells invitro, however, resulted in loss of membrane integrity in both freeze-sensitive and freeze-tolerant larvae. Different additives showed widely different capacities to protect membrane integrity when added to invitro freezing media. A complete rescue of membrane integrity in freeze-tolerant larvae was observed with a mixture of proline, trehalose, and BSA.

Seasonal Dynamics of Fruit Flies (Diptera: Drosophilidae) in Forests of the European Russia.

Simple SummaryIt is the first investigation of drosophilid seasonal population changes considering their biotope association, abundance and species diversity in European Russia. The material was collected using beer traps in different forest biotopes. Beer is an attractive component for fruit flies. Two species were most common (Drosophila obscura and Drosophila histrio). We found three groups of mass species with a significant correlation of seasonal dynamics.(1) Background: Seasonal dynamics of the abundance and species diversity of various insect groups is of great importance for understanding their life cycles; (2) Methods: In our study, Drosophilidae species and their seasonal changes in Mordovia State Nature Reserve were explored. We collected the flies by crown fermental traps in five types of forests (birch, aspen, linden, pine and oak) since May to October in 2019. (3) Results: A total of 4725 individuals belonging to 9 genera and 30 species of drosophilid flies were identified, among them 15 species in 3 genera are new to the Republic of Mordovia. Drosophila obscura and D. histrio were the most abundant species in traps, the other mass species are D. kuntzei, D. testacea, D. phalerata, S. rufifrons, D. bifasciata, A. semivirgo, and L. quinquemaculata. (4) Conclusions: We found three groups of mass species with significant correlation of seasonal dynamics, e.g., D.obscura and D. bifasciata; D. histrio, D. kuntzei, D. phalerata, and D. testacea, and, finally, A. semivirgo and S. rufifrons. Apparently, the similarity observed in the seasonal dynamics of these drosophilid species is influenced at a high degree by their food preferences and rearing sites.

Dietary Utilization Drives the Differentiation of Gut Bacterial Communities between Specialist and Generalist Drosophilid Flies.

ABSTRACTGut bacteria play vital roles in the dietary detoxification, digestion, and nutrient supplementation of hosts during dietary specialization. The roles of gut bacteria in the host can be unveiled by comparing communities of specialist and generalist bacterial species. However, these species usually have a long evolutionary history, making it difficult to determine whether bacterial community differentiation is due to host dietary adaptation or phylogenetic divergence. In this regard, we investigated the bacterial communities from two Araceae-feeding Colocasiomyia species and further performed a meta-analysis by incorporating the published data from Drosophila bacterial community studies. The compositional and functional differentiation of bacterial communities was uncovered by comparing three (Araceae-feeding, mycophagous, and cactophilic) specialists with generalist flies. The compositional differentiation showed that Bacteroidetes and Firmicutes inhabited specialists, while more Proteobacteria lived in generalists. The functional prediction based on the bacterial community compositions suggested that amino acid metabolism and energy metabolism are overrepresented pathways in specialists and generalists, respectively. The differences were mainly associated with the higher utilization of structural complex carbohydrates, protein utilization, vitamin B12 acquisition, and demand for detoxification in specialists than in generalists. The complementary roles of bacteria reveal a connection between gut bacterial communities and fly dietary specialization.IMPORTANCE Gut bacteria may play roles in the dietary utilization of hosts, especially in specialist animals, during long-term host-microbe interaction. By comparing the gut bacterial communities between specialist and generalist drosophilid flies, we found that specialists harbor more bacteria linked to complex carbohydrate degradation, amino acid metabolism, vitamin B12 formation, and detoxification than do generalists. This study reveals the roles of gut bacteria in drosophilid species in dietary utilization.

An annotated list of the drosophilid flies (Diptera: Drosophilidae) of Buryatia

An annotated list of 18 species in six genera of the drosophilid flies of Buryatia is given. Among them 13 species are recorded from Buryatia for the first time. The drosophilid fauna of Buryatia is compared with the fauna of Tuva.

Phortica oldenbergi (Diptera: Drosophilidae): A new potential vector of the zoonotic Thelazia callipaeda eyeworm

Thelazia callipaeda is a zoonotic nematode parasitizing the eyes of many hosts species, primarily dogs. To date Phortica variegata and Phortica okadai are the only known vectors of this nematode in Europe and China, respectively. In this study we investigated the role played by a third species, Phortica oldenbergi, as vector of T. callipaeda in Europe. Drosophilid flies of this species were collected in central Italy and maintained in laboratory. One hundred forty P. oldenbergi were experimentally infected with T. callipaeda L1 recovered from field collected gravid females belonging to haplotype 1, which is that detected in several countries in Europe. Seventy-four (i.e., 60 females and 14 males) specimens died at 5 days post infection (d.p.i.) (±1) and scored negative for T. callipaeda larvae at the dissection. Sixty-six (i.e., 46 females and 20 males) P. oldenbergi survived and were dissected at 21 d.p.i. From those, T. callipaeda L3 were detected in the proboscis of two females (3.0%). Overall, at the molecular analysis, 11.4% (n = 16/140; 13 females and 3 males) scored positive for the presence of T. callipaeda DNA. Data herein reported brings further insights on the biology of T. callipaeda by adding P. oldenbergi as a new potential intermediate host under experimental conditions. The role of this drosophilid in the transmission cycle of T. callipaeda needs to be confirmed under natural conditions.