Selective pollination by fungus gnats potentially functions as an alternative reproductive isolation among five Arisaema species.

BACKGROUND AND AIMS: Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors. METHODS: We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established ten experimental plots including the five Arisaema species in high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using a unified formula for reproductive isolation. KEY RESULTS: Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history. CONCLUSIONS: Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.

Specialized pollination by fungus gnats in the introduced population of Aspidistra elatior.

The monocot genus Aspidistra comprises rhizomatous perennials that are distributed in tropical to warm temperate regions of Asia. Little is known about the pollinators of almost all the species, probably due to the inconspicuous nature of Aspidistra flowers. Nevertheless, the unusual floral morphology suggests biotic pollination, since pollen grains are hidden under each flower's stigma. Aspidistra elatior has been suspected to have a very peculiar pollination ecology. So far, pollination by mollusks, crustaceans, or collembolans has been suspected. However, a recent study showed that A. elatior is mainly pollinated by species of fungus gnats in Kuroshima Island, southern Japan, which is its natural habitat. Here, we investigated the pollination ecology of A. elatior in Shiga Prefecture, central Japan, which is the introduced population, to reveal whether fungus gnats are also the main pollinator in the introduced population. Our study confirmed fungus gnats pollination in the investigated pollination. Furthermore, the main pollinators (i.e., Cordyla sixi and Bradysia sp.) are the same in both Kuroshima and Shiga Prefecture. Therefore, A. elatior mainly depends on a narrow taxonomic group of fungus gnats for pollination. In contrast, we failed to document any terrestrial amphipods visiting the A. elatior flowers, in spite of a relatively high fruit set in natural conditions. This fact will refute the amphipod pollination hypothesis proposed by previous studies. We consider that A. elatior is pollinated by fungus gnats through fungal mimicry, due to its superficial similarity to mushroom fruiting bodies and strong, musky floral scent.

Increased decomposer diversity accelerates and potentially stabilises litter decomposition.

Little is known about the effect of decomposer diversity on litter decomposition in alpine areas. Especially under the premise that alpine ecosystems are very sensitive to global change and are currently undergoing extensive land-use changes, a better understanding is needed to predict how environmental change will affect litter decomposition. A mesocosm experiment was conducted to compare the effects of the most common and functionally diverse invertebrates (earthworms, millipedes and sciarid larvae) found in alpine soils on decomposition rates and to assess how decomposer diversity affects litter decomposition. Experimental and estimated (i.e. projected to field decomposer-biomass) litter mass loss was 13-33% higher in the three-species treatment. Notably, the variability in decomposition was greatly reduced when decomposer diversity was high, indicating a portfolio effect. Our results suggest that invertebrate decomposer diversity is essential for sustaining litter decomposition in alpine areas and for the stability of this service.

The number of Estonian black fungus gnats (Diptera, Sciaridae) doubled: the first records of 64 species.

Background: Adult sciarid flies are small to medium-sized, delicate insects, typically black in colour and belonging to the superfamily Sciaroidea within the order Diptera. They exhibit a uniform appearance. Distinguishing them from other families of Sciaroidea is primarily achieved through their typical wing venation. Sciaridae are common in both natural and semi-natural ecosystems, where they play a significant role in decomposition during their larval stage. Prior to the current study, only one specific research project had been conducted on Sciaridae in Estonia. The number of sciarid species identified in Estonia was set at 67. New information: This research, conducted in north-eastern Estonia during 2015 and 2016, presents a comprehensive overview of Sciaridae diversity, shedding light on previously understudied aspects of Estonia's biodiversity. A total of 1038 specimens were identified, representing 91 species, amongst which 64 were previously unknown to Estonia. Notably, Corynopterawinnertzi (Mohrig, 1993) emerged as the most abundant species, followed by Corynopterairmgardis (Lengersdorf, 1930), Corynopteracrassistylata (Frey, 1948) and Bradysiatrivittata (Staeger, 1840). The genus Corynoptera Winnertz, 1867 exhibited the highest diversity, consistent with findings from broader European studies. This study underscores the importance of ongoing surveys for better understanding the distribution and composition of Sciaridae species in Estonia, emphasising the need for further research to delve into the intricate ecology and biology of these insects.

Pseudolycoriella hygida (Sauaia and Alves)-An Overview of a Model Organism in Genetics, with New Aspects in Morphology and Systematics.

Pseudolycoriella hygida (Sauaia & Alves, 1968) is a sciarid that has been continuously cultured in the laboratory for nearly 60 years. Studies on this species have contributed to the understanding of DNA puffs, which are characteristic of Sciaridae, and to the knowledge of more general aspects of insect biology, including cell death, nucleolar organization, and the role of the hormone ecdysone during molting. The genome of Psl. hygida has now been sequenced, and it is the third publicly available sciarid genome. The aim of this work is to expand the current knowledge on Psl. hygida. The morphology of the adults is revisited. The morphology of larvae and pupae is described, together with the behavior of immature stages under laboratory conditions. Cytogenetic maps of the salivary gland polytene chromosomes are presented, together with a comparative analysis of the mitotic chromosomes of six different sciarid species. Pseudolycoriella hygida was originally described as a species of Bradysia and recently moved to Pseudolycoriella. We examine here the systematic position of Psl. hygida in the latter genus. Our results extend the characterization of an unconventional model organism and constitute an important resource for those working on the cytogenetics, ecology, taxonomy, and phylogenetic systematics of sciarids.

Review of the Genus Sciara Meigen, 1803 (Diptera, Sciaridae) in Ukraine.

On the territory of Ukraine during the field seasons 2015-2022, we collected eight Sciara species-S. analis Schiner, 1864, S. flavimana Zetterstedt, 1851, S. hebes (Loew, 1869), S. helvola Winnertz, 1867, S. hemerobioides (Scopoli, 1763), S. humeralis Zetterstedt, 1851, S. incerta Winnertz, 1867 and S. ruficauda Meigen, 1818. All specimens are kept in the collections of the Schmalhausen Institute of Zoology NAS of Ukraine (SIZK). According to the results of our research, the four species S. flavimana, S. hebes, S. helvola and S. incerta are being registered for the first time in Ukraine. New localities are given for S. analis, S. hemerobioides, S. humeralis and S. ruficauda. The distribution, morphological peculiarities, ecology and phenology of registered species are also briefly discussed. A key to 12 European Sciara species is given.

The Genus Spinopygina gen. nov. (Diptera, Sciaridae) from Western North America: Preliminary Molecular Phylogeny and Description of Seven New Species.

The genus Spinopygina gen. nov. (type species Camptochaeta uniceps Hippa & Vilkamaa, 1994) from western North America is described. The genus includes the following eight species: Spinopygina acerfalx sp. nov.; S. aurifera sp. nov.; S. camura sp. nov.; S. edura sp. nov.; S. peltata sp. nov.; S. plena sp. nov.; S. quadracantha sp. nov.; and S. uniceps (Hippa & Vilkamaa, 1994) comb. nov., transferred from Corynoptera Winnertz. The new species are described and Spinopygina uniceps is re-diagnosed. The species are keyed and illustrated. In the maximum-likelihood phylogenetic hypothesis based on four gene fragments (28S, 18S, 16S and COI), Spinopygina gen. nov. appears as the sister group of Claustropyga Hippa, Vilkamaa & Mohrig, 2003. In the same analysis, a remarkable, undescribed species is placed within Camptochaeta Hippa & Vilkamaa clade.

Effect of microplastics and watering regimes on a plant-soil system: Data on behavioural responses of an insect herbivore.

The data presented here are related to the article titled "Microplastics alter behavioural responses of an insect herbivore to a plant-soil system" by Rondoni, G., Chierici, E., Agnelli, A., Conti, E. (2021). The data describe the changes in the attractiveness of a plant-soil system towards females of a herbivorous fungus gnat (Diptera: Sciaridae) when exposed to different combinations of the following treatments: (1) low or high plant (lentil)-soil watering regime; (2) absence (0%) or presence (5%) of HDPE microplastics in soil; (3) 1-day or 7-day duration of HDPE presence; (4) addition of fungus mycelium to the plant-soil system. We report data of female behaviour, i.e. the residence time in choice vs. no-choice sector of one-way olfactometers using a multiple olfactometer device.

Chromosome End Diversification in Sciarid Flies.

BACKGROUND: Dipterans exhibit a remarkable diversity of chromosome end structures in contrast to the conserved system defined by telomerase and short repeats. Within dipteran families, structure of chromosome termini is usually conserved within genera. With the aim to assess whether or not the evolutionary distance between genera implies chromosome end diversification, this report exploits two representatives of Sciaridae, Rhynchosciara americana, and Trichomegalosphyspubescens. METHODS: Probes and plasmid microlibraries obtained by chromosome end microdissection, in situ hybridization, cloning, and sequencing are among the methodological approaches employed in this work. RESULTS: The data argue for the existence of either specific terminal DNA sequences for each chromosome tip in T. pubescens, or sequences common to all chromosome ends but their extension does not allow detection by in situ hybridization. Both sciarid species share terminal sequences that are significantly underrepresented in chromosome ends of T. pubescens. CONCLUSIONS: The data suggest an unusual terminal structure in T. pubescens chromosomes compared to other dipterans investigated. A putative, evolutionary process of repetitive DNA expansion that acted differentially to shape chromosome ends of the two flies is also discussed.

Proposal of a new subfamily of Sciaridae (Diptera: Sciaridae), with description of one new species from South Korea.

Here we propose a new monophyletic subfamily, the Chaetosciarinae, based on previous morphological cladistic and molecular phylogenetic studies. This new subfamily includes the genera Chaetosciara Frey, Mouffetina Frey, Schwenckfeldina Frey, and Scythropochroa Enderlein. We also provide a definition of the new subfamily Chaetosciarinae and describe common morphological key characters. Three Korean Chaetosciarinae species in three genera are reported, all of which are new to Korea and one (Scythropochroa pseudoquercicola sp. nov.) of which is new to science. A previous molecular phylogenetic study designated Scy. pseudoquercicola as an unidentified species. Our study provides examined species information for members of this new subfamily to accompany the GenBank accession numbers published by a previous molecular phylogenetic study. Furthermore, we present a multigene molecular phylogenetic analysis for the Chaetosciarinae.

Morphology and DNA barcodes of two species of Bradysia Winnertz from China (Diptera, Sciaridae), with the description of Bradysia minorlobus Yang, Shi amp; Huang sp. n.

Two morphologically similar species of the fungicola species group of Bradysia Winnertz, 1867 were studied in China: Bradysia chenjinae Yang, Zhang Yang, 1993 and Bradysia minorlobus Yang, Shi Huang sp. n. The morphological species concepts were supported by the DNA barcodes of COI sequences. The genetic distances of 16 Bradysia fungicola group species were analyzed and a neighbor-joining tree was constructed. The morphological characters of both Chinese species were described and illustrated.

Review of Pseudoaerumnosa Rudzinski (Diptera, Sciaridae), with the description of twenty-four new species.

The genus Pseudoaerumnosa Rudzinski, 2006 is redefined. The genus includes the following species which are described, illustrated and keyed: Pseudoaerumnosa acinacea sp. n., P. ampliata sp. n., P. annae sp. n., P. awanensis sp. n., P. banari sp. n., P. clavidactyla sp. n., P. clivicola sp. n., P. collicola sp. n., P. consuota sp. n., P. cryptoloba sp. n., P. curvifalx sp. n., P. eminula sp. n., P. exacuta sp. n., P. filispicata sp. n., P. formosa sp. n., P. fragilis sp. n., P. impensa sp. n., P. inviolata Rudzinski, 2006, P. junciseta sp. n., P. obovata sp. n., P. pilicaudata sp. n., P. quadriquetra sp. n., P. saginata sp. n., P. tenuidens sp. n. and P. tkoci sp. n. Morphological characters and the phylogenetic position of Pseudoaerumnosa are discussed. For some species, the barcode (COI) sequence data were obtained. The genus is currently known from the Oriental (22 species), Malagasy (3 species) and Australasian regions (1 species).

Characterizing the embryonic development of B. hygida (Diptera: Sciaridae) following enzymatic treatment to permeabilize the serosal cuticle.

Understanding the evolution of the developmental programs active during dipteran embryogenesis depends on comparative studies. As a counterpoint to the intensively investigated and highly derived cyclorrhaphan flies that include the model organism Drosophila melanogaster, we are studying the basal Diptera Bradysia hygida, a member of the Sciaridae family that is amenable to laboratory cultivation. Here we describe the B. hygida embryogenesis, which lasts 9 days at 22 °C. The use of standard fixation D. melanogaster protocols resulted in embryos refractory to DAPI staining and to overcome this, a new enzyme-based method was developed. Calcofluor-White staining of enzimatically-treated embryos revealed that this method removes chitin from the serosal cuticle surrounding the B. hygida embryo. Chitin is one of the main components of serosal cuticles and searches in a B. hygida embryonic transcriptome database revealed conservation of the chitin synthesis pathway, further supporting the occurrence of chitin biosynthesis in B. hygida embryos. Combining the enzymatic treatment protocol with the use of both DIC and fluorescence microscopy allowed the first complete description of the B. hygida embryogenesis. Our results constitute an important step towards the understanding of early development of a basal Diptera and pave the way for future evo-devo studies.

Remarkable fly (Diptera) diversity in a patch of Costa Rican cloud forest: Why inventory is a vital science.

Study of all flies (Diptera) collected for one year from a four-hectare (150 x 266 meter) patch of cloud forest at 1,600 meters above sea level at Zurquí de Moravia, San José Province, Costa Rica (hereafter referred to as Zurquí), revealed an astounding 4,332 species. This amounts to more than half the number of named species of flies for all of Central America. Specimens were collected with two Malaise traps running continuously and with a wide array of supplementary collecting methods for three days of each month. All morphospecies from all 73 families recorded were fully curated by technicians before submission to an international team of 59 taxonomic experts for identification.        Overall, a Malaise trap on the forest edge captured 1,988 species or 51% of all collected dipteran taxa (other than of Phoridae, subsampled only from this and one other Malaise trap). A Malaise trap in the forest sampled 906 species. Of other sampling methods, the combination of four other Malaise traps and an intercept trap, aerial/hand collecting, 10 emergence traps, and four CDC light traps added the greatest number of species to our inventory. This complement of sampling methods was an effective combination for retrieving substantial numbers of species of Diptera. Comparison of select sampling methods (considering 3,487 species of non-phorid Diptera) provided further details regarding how many species were sampled by various methods.        Comparison of species numbers from each of two permanent Malaise traps from Zurquí with those of single Malaise traps at each of Tapantí and Las Alturas, 40 and 180 km distant from Zurquí respectively, suggested significant species turnover. Comparison of the greater number of species collected in all traps from Zurquí did not markedly change the degree of similarity between the three sites, although the actual number of species shared did increase.        Comparisons of the total number of named and unnamed species of Diptera from four hectares at Zurquí is equivalent to 51% of all flies named from Central America, greater than all the named fly fauna of Colombia, equivalent to 14% of named Neotropical species and equal to about 2.7% of all named Diptera worldwide. Clearly the number of species of Diptera in tropical regions has been severely underestimated and the actual number may surpass the number of species of Coleoptera.        Various published extrapolations from limited data to estimate total numbers of species of larger taxonomic categories (e.g., Hexapoda, Arthropoda, Eukaryota, etc.) are highly questionable, and certainly will remain uncertain until we have more exhaustive surveys of all and diverse taxa (like Diptera) from multiple tropical sites.        Morphological characterization of species in inventories provides identifications placed in the context of taxonomy, phylogeny, form, and ecology. DNA barcoding species is a valuable tool to estimate species numbers but used alone fails to provide a broader context for the species identified.

Descriptions of new species of the genera Camptochaeta Hippa & Vilkamaa and Corynoptera Winnertz (Diptera, Sciaridae) from the Holarctic.

Six species of the genus Camptochaeta Hippa & Vilkamaa, 1994 and four of the genus Corynoptera Winnertz, 1867 from the Holarctic region are newly described and illustrated: Camptochaeta chilkatensis sp. n. (USA: Alaska), C. curtipilosa sp. n. (USA: Colorado), C. exquisita sp. n. (USA: Oregon), C. fitzgeraldi sp. n. (USA: Oregon), C. fulvistylata sp. n. (Canada: British Columbia), C. pertenuis sp. n. (Russia: Krasnodarsk region), Corynoptera bocheri sp. n. (Greenland; Canada: Quebec), C. hyperborea sp. n. (Russia: Krasnodarsk region), C. hystricina sp. n. (RUSSIA: Krasnodarsk region) and C. tenuichaeta sp. n. (Russia: Krasnodarsk region).

Amplification and expression of a salivary gland DNA puff gene in the prothoracic gland of Bradysia hygida (Diptera: Sciaridae).

The DNA puff BhC4-1 gene, located in DNA puff C4 of Bradysiahygida, is amplified and expressed in the salivary gland at the end of the fourth larval instar as a late response to the increase in 20-hydroxyecdysone titer that triggers metamorphosis. Functional studies revealed that the mechanisms that regulate BhC4-1 expression in the salivary gland are conserved in transgenic Drosophila. These studies also led to the identification of a cis-regulatory module that drives developmentally regulated expression of BhC4-1-lacZ in the prothoracic gland cells of the ring gland, a compound organ which in Drosophila results from the fusion of the prothoracic glands, the corpus allatum and the corpus cardiacum. Here we have investigated the occurrence of BhC4-1 expression in B. hygida prothoracic glands. We report the identification of the B. hygida prothoracic gland and demonstrate that it releases ecdysone. Using RT-qPCR, western blots and immunolocalization experiments, we demonstrate that the BhC4-1 mRNA and the BhC4-1 protein are both expressed in the B. hygida prothoracic glands at the same time that DNA puff C4 is formed in the salivary gland. We also show that BhC4-1 is concomitantly amplified 4.8-fold in the prothoracic gland and 23-fold in the salivary gland. Our results reveal the occurrence of stage specific expression of a DNA puff gene in the prothoracic glands of B. hygida, and extend previous studies that have shown that DNA puff genes expression is not restricted to the salivary gland. In addition, the description of stage specific gene amplification in the prothoracic glands of B. hygida constitutes the first demonstration that gene amplification in Diptera might occur concomitantly in two different tissues in the same developmental stage.

Checklist of the family Sciaridae (Diptera) of Finland.

A checklist of the family Sciaridae (Diptera) recorded from Finland is provided. The genus Sciarosoma Chandler with a disputed family placement is also included in the list.

Taxonomy of the genus Peyerimhoffia Kieffer from Mainland China, with a description of seven new species (Diptera, Sciaridae).

The taxonomy of the genus Peyerimhoffia Kieffer in China was studied. Eight species were recognized, including seven new species that are herein described and illustrated: P. hamata sp. n., P. obesa sp. n., P. sparsula sp. n., P. longiprojecta sp. n., P. brachypodua sp. n., P. yunnana sp. n., and P. shennongjiana sp. n. In addition, P. vagabunda (Winnertz, 1867) is reported for the first time from China. A key to these Chinese species is provided.

The genus Camptochaeta in Nearctic caves, with the description of C. prolixa sp. n. (Diptera, Sciaridae).

Camptochaeta prolixasp. n. (Diptera, Sciaridae) is described from caves in Nevada, and three other congeneric species are recorded from caves in Nevada and Arkansas, United States. The new species shows some indication to a subterranean mode of life, including long antenna and legs, and in some specimens, reduction of the eye bridge.

The genus Keilbachia Mohrig from Mainland China, with descriptions of two new species (Diptera, Sciaridae).

Seven species of Keilbachia Mohrig are recognized, and among them, two new species, Keilbachia subacumina Wu & Zhang, sp. n. and Keilbachia fengyangensis Wu & Zhang, sp. n. are described and illustrated. Five species, Keilbachia orthonema, Keilbachia flagrispina, Keilbachia demssia, Keilbachia oligonema and Keilbachia acumina are reported for the first time from China. A key to the 15 Chinese species of this genus is also provided.