Fungus Gnats Research Articles

An essential oil blend of citronella, red thyme, and clove bud kills common hydroponic pests and pathogens

Protected cropping utilizing hydroponic systems are particularly vulnerable to the impacts of waterborne diseases which result in substantial crop damage and yield loss. This study assessed the potential of a citronella, red thyme, and clove bud essential oil blend (EOB) for plant safety, and pesticidal and antimicrobial activities. Results within model systems identified efficacy of EOB against aphids (p < 0.001), spider mites (p < 0.001), and fungus gnats (p < 0.001), and 250-fold diluted EOB against Pythium (p < 0.001), Phytophthora (p = 0.001), and Fusarium (p < 0.001). The plant safety trial indicated no impacts of 250-fold diluted EOB to capsicum health and glasshouse experiments demonstrated both curative and preventative efficacies against Pythium, based on reductions in the incidence and severity of infection. These results highlight the potential for the utilization of biopesticides for the effective and environmentally friendly management of common pests and diseases within hydroponic crop systems.

Fungus gnat pollination in Arisaema urashima: the interplay of lethal traps and mutualistic nurseries.

While most flowering plants engage in mutualistic interactions with their pollinators, Arisaema species employ a unique, seemingly antagonistic strategy by imprisoning and causing the pollinators to perish within their spathes. Recent studies have revealed that Arisaema thunbergii primarily relies on a fungus gnat, Leia ishitanii, with some individuals possibly escaping female spathes after oviposition. We investigated interactions between A. urashima and its pollinating fungus gnats, given that A. urashima is closely related to A. thunbergii. Specifically, we tested whether decaying A. urashima serve as brood-sites for some pollinators and whether these pollinators can escape seemingly lethal floral traps. We retrieved A. urashima spathes together with adult insect corpses trapped within the spathes and incubated the spathes to see if conspecific insects emerged. In addition, under laboratory conditions, we observed the escape behaviour of Sciophila yokoyamai, whose next-generation adults most frequently emerge from the decaying spathes. Our findings indicate that S. yokoyamai almost always escapes from the female spathe after oviposition while using the inflorescence as a nursery. In contrast, other pollinators of A. urashima, including Mycetophila spp., remain trapped and perished within the spathes. This study demonstrates that A. urashima spathes can function both as lethal traps and mutualistic nurseries, with outcomes differing among pollinator species. Our results also suggest that the contribution of certain pollinators to Arisaema reproduction is underestimated or even neglected, given that information on their pollinator assemblages has been based on floral visitors trapped within the inflorescences.

Taxonomy and DNA barcoding of the dark-winged fungus gnat genus Zygoneura Meigen (Diptera: Sciaridae) from China, with revision of the type materials

The genus Zygoneura Meigen is revised thoroughly from China, and 14 species are recognized and illustrated, including four new species: Zygoneura (Allozygoneura) xizangensis Shah &amp; Huang sp. nov., Zygoneura (Pharetratula) minuscula sp. nov., Zygoneura (Pharetratula) motuoensis sp. nov. and Zygoneura (Pharetratula) yangi sp. nov. In addition, Zygoneura (Pharetratula) divergens (Mamaev), Zygoneura (Pharetratula) flavicornis (Mamaev), and Zygoneura (Pharetratula) subdivergens (Mohrig &amp; Mamaev) are reported for the first time from China. The identification of these species is supported by both morphological characteristics and sequence data obtained from cytochrome oxidase subunit one (COI) in the DNA barcode analysis. Furthermore, a checklist of the known Zygoneura species in China is also provided, along with an identification key for males.

Photographic monitoring of glowworm Arachnocampa luminosa (Diptera: Keroplatidae) bioluminescence in a tourist cave reveals diurnal and annual cycles

AbstractGlowworms are the bioluminescent larvae of a group of dipteran insects related to fungus gnats. They require sheltered, consistently moist conditions and are found in aggregations on the walls and ceilings of caves and near streams in wet forests where they attract flying insects as prey. The Waitomo Glowworm Cave in New Zealand receives many thousands of visitors each year to see the colony of the glowworm, Arachnocampa luminosa. The cave climate is managed to ensure the glowworms are not harmed by influxes of dry air, as happened in the 1970s. To monitor the population and warn of catastrophic population declines, time‐lapse photographic monitoring of the glowworm population began in 2011 using a permanent, fixed camera. Photographs are taken 30 min apart. The population exhibits synchronised diurnal cycles of bioluminescence intensity. The time of the acrophase (the peak) of the diurnal cycle varied seasonally between 5 pm in early southern spring and 8 pm in summer. Cross‐correlation analyses with cave and water temperatures incorporating time lags suggest that this annual cycle could be related to changes in the composition or density of prey insects. Annual cycles also occur in the number of glowing larvae and their overall intensity. In most years, the numbers are lowest in winter and increase in spring to produce the brightest display through summer. The summer peak is not seen every year and autocorrelation of the 13‐year time series of count shows signs of a 3‐ to 4‐year cycle beyond the annual periodicity. The availability of prey in the cave chamber could influence the annual cycles in glowworm density, underscoring the need for a deeper knowledge of the bionomics of prey species, mainly Chironomidae (non‐biting midges). The photographic monitoring has proven to be a useful component of the management of the glowworm population.

Vibrations as a new tool for pest management – a review

AbstractSensory stimuli are essential for arthropod survival and reproduction. Given the widespread use of vibrational communication among diverse taxa, exploiting vibrational senses has great potential for successful pest management. In this review, we summarize our recent findings on vibration‐based pest management and future perspectives in the context of integrated pest management. We first examine the management of whiteflies – the tobacco whitefly, Bemisia tabaci (Gennadius) and the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) – in various facilities where tomatoes are cultivated. We then explore the recent application of vibration for the control of fungus gnats of the genus Neoempheria (Diptera: Mycetophilidae) infesting shiitake mushrooms. Finally, we discuss the control of the brown‐winged green stink bug, Plautia stali Scott (Hemiptera: Pentatomidae), a pest of fruit trees in Japan. Notably, our trials have demonstrated that vibrational treatments are profitable not only for reducing pest populations but also for indirect benefits such as increased crop yields or the enhancement of pest control effectiveness.

Fixed non-random orientation to the Sun (conversotropism) in two window-flowered greenhood orchids, Diplodium spp. (Orchidaceae: Pterostylidinae); implications for other window flowers and pollinator behaviour

Abstract Many plant species orient their flowers to the Sun. Such orientations may be dynamic (heliotropism or solar tracking) or static, adopting fixed non-random azimuths to points on the daily arc of the Sun (conversotropism as defined herein). Two cauline greenhood orchid species, Diplodium reflexum and D. ampliatum (Pterostylidinae), are shown to be negatively conversotropic and non-heliotropic. Cauline greenhoods are trap and window flowers having large translucent light panels that glow when backlit flowers are viewed from the front. Conversotropism in greenhoods is thought to maximize light transmission through the window panels to manipulate the behaviour of fungus gnat pollinators. Conversotropism is so far documented in only seven species in five plant families, but is likely to be more widespread. The general characteristics of conversotropism are summarized and a new two stage model of window function in greenhoods is proposed. Window flowers in the Lady Slipper orchids (Cypripedium) and in Arums of the genus Arisaema are also predicted to be conversotropic. The evolution of conversotropism in cauline greenhoods highlights the importance of floral windows in these orchids. The highly unusual trap flowers may use light both as a pollinator attractant and repellent at different stages of the pollination process. Greenhoods appear to exploit the instinct of flies to escape confinement and the behaviours enabling it. This probably also applies to other trap flowers and adds insect escape behaviours to the many other drives, instincts, and behaviours exploited by plants for pollination.

Diversified Roles of Insects in Essential Ecosystem through Pollination for Achieving Sustainable Goals

Pollination is an ecological process that involves the transfer of pollen from the male to the female part of the flower with the help of various abiotic and biotic pollen dispersal agents and is an essential pre-requisite for fertilization and fruit/seed dispersal. Insects constitute one of the primary groups of pollinating agents, as the association between insects and flowers is well established. As flowers radiated so did the mouthparts of the insects exploiting them. Various insect groups, which are of prime significance in the pollination of agricultural and horticultural crops mainly belong to the orders Hymenoptera (bees, ants and wasps), Diptera (flies, mosquitoes, fungus gnats, midges), Coleoptera (beetles and weevils), Lepidoptera (moths and butterflies), Thysanoptera (thrips), Hemiptera (bugs) and Neuropteran (lace wing flies). This work is mainly based on detailed and through observations/study made from various cash crops viz., Brassica nigra, Coriandrum sativum, Tagetes erecta and Helianthus annuus from North 24 Parganas of South Bengal region.

Back from the dead: A fungus gnat pollinator turns Arisaema lethal trap into nursery

Societal Impact StatementThe research explores the complex interaction between flowering plants and their pollinators, specifically focusing on the genus Arisaema. Unlike most plants, Arisaema has a distinctive trait in which killing pollinators can be beneficial. Traditionally, this interaction has been viewed as highly antagonistic because it appears to favor the plants at the expense of the pollinators. However, new evidence reveals that a pollinator uses the lethal floral trap of Arisaema thunbergii as a nursery. Remarkably, some individuals probably even escape from the trap after laying eggs. This finding challenges the prevailing notion that deceptive pollination is the sole outcome in Arisaema, a genus known for its intricate lethal pollination mechanisms.Summary While many flowering plants engage in mutualistic relationships with their pollinators, flower‐insect interactions are not always mutually beneficial. Some plants exploit their pollinators by deceptively promising rewards without delivering them. Among such plants, the genus Arisaema (Araceae) is notable for its antagonistic behavior towards pollinators, as female plants invariably entrap them with lethal effects. Here we tested the hypothesis that the succulent appendix of some Arisaema species, such as Arisaema thunbergii, may serve as a food source for pollinator larvae, leading to the possibility of nursery pollination. To investigate this, we retrieved adult insect corpses trapped within the spathes of A. thunbergii. Subsequently, we incubated the spathes after collecting the corpses to determine if conspecific insects emerged from them. We present novel evidence that one of the main pollinating fungus gnats, Leia ishitanii, uses the lethal floral trap of A. thunbergii inflorescences as a nursery. Astonishingly, some L. ishitanii individuals may even succeed in escaping from the female spathe after depositing their eggs. These findings challenge the conventional understanding that deceptive pollination is the norm within the genus Arisaema. The interaction between A. thunbergii and L. ishitanii, in which a significant portion of female adults die inside but still reproduction seems successful, suggests an intermediate stage between brood‐site deception and nursery pollination mutualism.

Fungus gnats (Diptera: Sciaridae) causam danos na cultura da rosa do deserto (Adenium obesum Forssk. Roem. &amp; Schult) em Jataí - Goiás, Brasil

ABSTRACT: Recent rise in desert rose production, the expanded cultivation of this species may promote infestation by certain insects and mites. One such insect, the fungus gnats (Bradysia sp), also known as fungus flies, have been damaging numerous ornamental plant species. This study reported the incidence of fungus gnats infesting desert rose plants in the municipality of Jataí - GO, Brazil. Throughout 2022, we evaluated 48 desert rose plants for parasitic occurrences through direct observation. Sticky traps were used to record adult insects. Damage to plant organs has been documented and the presence of parasites at various stages of development with digital photographs. The incidence of fungal gnats is confirmed by observing adult insects and larvae in the plant substrate and roots. Of the 48 plants evaluated, 39 showed signs of infestation. Symptoms of a fungus gnat attack on desert rose include small necrotic lesions on new roots, progressive root rot, and a withered caudex resembling dehydration. The fungus gnats attack can cause the desert rose caudex to wilt, reducing its size and losing part of its shape, fact that can compromise the commercialization of this crop.

The characteristics of the families Anisopodidae and Mycetophilidae (Insecta: Diptera)

The Anisopodidae is a cosmopolitan family of Diptera belonging to the mosquito group. The larvae live and feed on all types of decomposing material such as excrement, manure, vegetables, or dead wood. Adults are found mainly in summer in forests, meadows, and gardens, they are regularly seen on windows, both indoors and outdoors, which is why they have been called “window mosquitoes” or “wood mosquitoes”. Mycetophilidae in Brazil, this insect mainly damages ornamental plants and causes great damage. Also, in seedlings of different crops, such as citrus, tobacco, strawberry, and others. Many sites on the internet say that adults do not harm plants, but this is a mistake. Fungus gnats’ mosquitoes can cause great damage but in an indirect way. These little mosquitoes can carry harmful pathogens, that is, they can carry and spread diseases to your plants. The larvae can feed on the roots, and leaves and can even be found inside the stem, this is especially bad for young plants, such as seedlings, which have only a few delicate roots. Therefore, when you see two plants withering or turning yellow, this could be caused by fungus gnats (without roots the plant cannot absorb water or nutrients). The most common insect causing damage to greenhouses and indoor plants. The objective of the manuscript is to characterize the Anisopodidae and Mycetophilidae families. The bibliographic review methodology consists of a review of existing bibliographic material that concerns the subject to be studied. This is one of the main steps for any research and includes the selection of different sources of information, which can be collected in theoretical books; Banks of theses and dissertations from universities; Scientific articles; Scientific magazines; Documents; Websites; A bibliographic research methodology includes a set of phases that cover questions such as 1-Observation; Inquiry; Interpretation; Reflection; Analysis.

Bradysia (Sciara) coprophila larvae up-regulate DNA repair pathways and down-regulate developmental regulators in response to ionizing radiation.

The level of resistance to radiation and the developmental and molecular responses can vary between species, and even between developmental stages of one species. For flies (order: Diptera), prior studies concluded that the fungus gnat Bradysia (Sciara) coprophila (sub-order: Nematocera) is more resistant to irradiation-induced mutations that cause visible phenotypes than the fruit fly Drosophila melanogaster (sub-order: Brachycera). Therefore, we characterized the effects of and level of resistance to ionizing radiation on B. coprophila throughout its life cycle. Our data show that B. coprophila embryos are highly sensitive to even low doses of gamma-irradiation, whereas late-stage larvae can tolerate up to 80 Gy (compared to 40 Gy for D. melanogaster) and still retain their ability to develop to adulthood, though with a developmental delay. To survey the genes involved in the early transcriptional response to irradiation of B. coprophila larvae, we compared larval RNA-seq profiles with and without radiation treatment. The up-regulated genes were enriched for DNA damage response genes, including those involved in DNA repair, cell cycle arrest, and apoptosis, whereas the down-regulated genes were enriched for developmental regulators, consistent with the developmental delay of irradiated larvae. Interestingly, members of the PARP and AGO families were highly up-regulated in the B. coprophila radiation response. We compared the transcriptome responses in B. coprophila to the transcriptome responses in D. melanogaster from 3 previous studies: whereas pathway responses are highly conserved, specific gene responses are less so. Our study lays the groundwork for future work on the radiation responses in Diptera.

Pollinators of Arisaema nambae (Araceae), endemic to Okayama and Hiroshima prefectures, western Japan

Effective pollinators of Arisaema nambae Kitam., endemic to western Okayama and eastern Hiroshima prefectures, western Japan, were determined, and 113 insects from 24 spathes of A. nambae in three populations in Okayama Prefecture were collected. Most floral visitors were fungus gnats (Mycetophilidae and Sciaridae). Their maximum body width was less than the internal diameter (ca. 2 mm) of the exit at the bottom of the staminate spathe. Pollen grains of Arisaema attached to the bodies of fungus gnats collected from pistillate spathes provided evidence that they visited the pistillate spathe after escaping from staminate spathes. Based on their visitation frequency, size compatibility between their body and the exit from the staminate spathes and the pollen loads they carry, fungus gnats appear to play an important role in the pollination of A. nambae.

Post-pollination barriers contribute to coexistence of partially pollinator-sharing Arisaema species (Araceae).

Reproductive isolation plays an important role in maintaining the species integrity of sympatric close relatives. For sympatric Arisaema species, interspecific gene flow is expected to be effectively prevented by pre-pollination barriers, particularly strong pollinator isolation mediated by fungus gnats. However, due to the lack of quantitative studies combining multiple pre- and post-pollination barriers, it is not known whether pre-pollination isolation is complete, and whether post-pollination barriers also contribute to reproductive isolation among some Arisaema species. In this study, we quantified the individual strengths and absolute contributions of four pre- and post-pollination barriers (phenological isolation, pollinator isolation, hybrid fruit formation, and hybrid seed formation) among three sympatric Arisaema species (A. bockii, A. lobatum, and A. erubescens). Although phenological isolation and pollinator isolation reduced the frequencies of interspecific pollen transfer among these species, the partial overlap of flowering times and pollinator assemblages resulted in incomplete pre-pollination isolation. Post-pollination barriers also contributed to reproductive isolation at the hybrid fruit and seed formation stages. We propose that, although pre-pollination barriers are expected to contribute more to total isolation than post-pollination barriers in Arisaema, pre-pollination barriers may not completely prevent interspecific pollen transfer among some Arisaema species. Post-pollination barriers, which are generally ignored, may also have contributed significantly to reproductive isolation in Arisaema.

Fungus Gnat (Diptera: Sciaridae) as an Emergent Pest Associated with Berry Production in Mexico

Fungus Gnat (Diptera: Sciaridae) as an Emergent Pest Associated with Berry Production in Mexico

Adaptation to pollination by fungus gnats underlies the evolution of pollination syndrome in the genus Euonymus.

Dipteran insects are known pollinators of many angiosperms, but knowledge on how flies affect floral evolution is relatively scarce. Some plants pollinated by fungus gnats share a unique set of floral characters (dark red display, flat shape and short stamens), which differs from any known pollination syndromes. We tested whether this set of floral characters is a pollination syndrome associated with pollination by fungus gnats, using the genus Euonymus as a model. The pollinator and floral colour, morphology and scent profile were investigated for ten Euonymus species and Tripterygium regelii as an outgroup. The flower colour was evaluated using bee and fly colour vision models. The evolutionary association between fungus gnat pollination and each plant character was tested using a phylogenetically independent contrast. The ancestral state reconstruction was performed on flower colour, which is associated with fungus gnat pollination, to infer the evolution of pollination in the genus Euonymus. The red-flowered Euonymus species were pollinated predominantly by fungus gnats, whereas the white-flowered species were pollinated by bees, beetles and brachyceran flies. The colour vision analysis suggested that red and white flowers are perceived as different colours by both bees and flies. The floral scents of the fungus gnat-pollinated species were characterized by acetoin, which made up >90 % of the total scent in three species. Phylogenetically independent contrast showed that the evolution of fungus gnat pollination is associated with acquisition of red flowers, short stamens and acetoin emission. Our results suggest that the observed combination of floral characters is a pollination syndrome associated with the parallel evolution of pollination by fungus gnats. Although the role of the red floral display and acetoin in pollinator attraction remains to be elucidated, our finding underscores the importance of fungus gnats as potential contributors to floral diversification.

Effective Laser Fly Control with Modulated UV-A Light Trapping for Mushroom Fungus Gnats (Diptera: Sciaridae)

Fungus gnats (Sciaridae) are one of the most devastating pests on mushroom farms. Generally, they are controlled using relatively inefficient physical means, like sticky or pheromone traps, or with chemical pesticides. Here, we have proposed an integrated fungus gnat control system combining a UV-A LED source at 365 nm and a high-power laser diode at 445 nm. The 365 nm UV-A LED serves a light trap, since previous studies have concluded that fungus gnats show maximum attraction in the range of 365–390 nm. The UV-A LED is also modulated at different frequencies, and the response of the gnats corresponding to these different frequencies was observed. We utilized an Arduino Uno microcontroller to run the integrated device, and a BASLER USB camera was used to capture the images. Our experiments indicated that a frequency of 40 Hz is the optimal choice for attracting the gnats most rapidly. Within 20 s of exposure, the UV-A LED operated at 40 Hz was found to trap approximately 80% of the gnats. In a restricted trapping zone measuring 2.5 × 2.5 × 3 cm3, our integrated module, which includes a 40 Hz modulated UV-A LED and a laser, resulted in a survival rate of only 50% for the total number of gnats. This outcome was accomplished through periodic 200 ms long exposures, amounting to a total duration of 2 min for a group of 100 gnats.

Mitochondrial alternative oxidase across the tree of life: Presence, absence, and putative cases of lateral gene transfer

The alternative oxidase (AOX) is a terminal oxidase in the electron transport system that plays a role in mitochondrial bioenergetics. The past 20 years of research shows AOX has a wide yet patchy distribution across the tree of life. AOX has been suggested to have a role in stress tolerance, growth, and development in plants, but less is known about its function in other groups, including animals. In this study, we analyzed the taxonomic distribution of AOX across >2800 species representatives from prokaryotes and eukaryotes and developed a standardized workflow for finding and verifying the authenticity of AOX sequences. We found that AOX is limited to proteobacteria among prokaryotes, but is widely distributed in eukaryotes, with the highest prevalence in plants, fungi, and protists. AOX is present in many invertebrates, but is absent in others including most arthropods, and is absent from vertebrates. We found aberrant AOX sequences associated with some animal groups. Some of these aberrant AOXs were contaminants, but we also found putative cases of lateral gene transfer of AOX from fungi and protists to nematodes, springtails, fungus gnats, and rotifers. Our findings provide a robust and detailed analysis of the distribution of AOX and a method for identifying and verifying putative AOX sequences, which will be useful as more sequence data becomes available on public repositories.

Black fungus gnat – An invasive pest of French bean in Bangladesh

French bean is an important vegetable in most tropical and subtropical countries and is a food source for humans and animals. A survey was carried out on the Patuakhali Science and Technology University (PSTU) campus, Narsingdi, Sylhet, Hobigonj, and Mowlovibazar districts of Bangladesh to know the incidence pattern of insect pests of French bean from November 2016 to January 2017. Field screening of nine French bean varieties against major insect pests was conducted in the Regional Horticulture Research Centre, BARI, Shibpur, Narsingdi, from November 2017 to January 2018. Seven varieties viz., BARI Jharsheem-1, BARI Jharsheem-2, BARI Jharsheem-3, Sylhet local- 4, Sylhet local-5, Sylhet local- 6 and Sylhet local-7 were used as study materials to evaluate against major insect pests of French bean under natural field condition. Results revealed that black fungus gnat was first noticed on 13th December, 2016 and the prevalence continued upto the 12th January, 2017. The highest incidence (21/plant) of black fungus gnat was found in Habiganj and the lowest (9/plant) was on the PSTU campus. The highest number of black fungus gnats were captured at 38 DAS (89/trap) and the lowest number (56/trap) of black fungus gnats were at 28 DAS using a yellow sticky trap. The variety BARI Jharshim-3 had the highest population of Black fungus gnats, which indicated that the variety was highly susceptible to Black fungus gnats, while Sylhet local-7 had the lowest population of black fungus gnats indicating least susceptible to Black fungus gnats. Among all tested varieties, none showed complete resistance against black fungus gnats. J. Asiat. Soc. Bangladesh, Sci. 49(1): 1-11, June 2023

New data on the fungus gnats (Diptera: Keroplatidae, Mycetophilidae) of Yakutia with description of three new species

New data on the fauna of the fungus gnats families Keroplatidae and Mycetophilidae of Yakutia is given. Thirty six species have been registered, including 20 species new to the region, bringing the total number of Yakut species to 86. Three species are reported for the first time from the Asian part of the Palaearctic region, and one species is new for Russia and Eurasia. Three species, Macrorrhyncha nocticolor sp. n., Docosia fasciculata sp. n. and Pseudexechia endybalensis sp. n. are described from Yakutia. Species diversity in the republic and relative knowledge on the fauna of different regions are briefly discussed.

Notes on the systematic position and distribution of Mycomya supernivea (Diptera, Mycetophilidae) in Japan

Mycomya supernivea Nakamura and Saigusa, 2020 is a recently described large-sized cold-adapted fungus gnat species known from the island of Hokkaido and the northern part of Honshu in Japan. This study reports the species for the first time from Shikoku Island and the central part of Honshu, indicating that the species is more widely distributed throughout the Japanese islands. Additionally, the systematic position of M. supernivae within the genus Mycomya is discussed, and it is placed under the subgenus Mycomya s. str. within the species group M. matrona.