Infection patterns of Harmonia axyridis (Coleoptera: Coccinellidae) by ectoparasitic microfungi and endosymbiotic bacteria

The invasive alien ladybird Harmonia axyridis (Coleoptera: Coccinellidae) hosts a wide range of natural enemies. Many observations have been done in nature but experimental studies of interactions of multiple enemies on Ha. axyridis are rare. In light of this knowledge gap, we tested whether the host phenotype and presence of bacterial endosymbionts Spiroplasma and Wolbachia affected parasitism of Ha. axyridis by the ectoparasitic fungus Hesperomyces harmoniae (Ascomycota: Laboulbeniales). We collected 379 Ha. axyridis in the Czech Republic, processed specimens, including screening for He. harmoniae and a molecular assessment for bacteria, and calculated fecundity and hatchability of females. We found that high hatchability rate (71 %) was conditioned by high fecundity (20 eggs daily or more). The average parasite prevalence of He. harmoniae was 53 %, while the infection rate of Spiroplasma was 73 % in ladybirds that survived in winter conditions. Wolbachia was only present in 2 % of the analyzed ladybirds. Infection by either He. harmoniae or Spiroplasma did not differ among host color morphs. In the novemdecimsignata morph, younger individuals (with orange elytra) were more heavily parasitized compared to old ones (with red elytra). Fecundity and hatchability rate of females were unaffected by infection with either He. harmoniae or Spiroplasma. However, female ladybirds co-infected with He. harmoniae and Spiroplasma had a significantly lower fecundity and hatchability compared to females with only one or no symbiont.

The haustorium as a driving force for speciation in thallus-forming Laboulbeniomycetes

Laboulbeniomycetes is a class of fungi that have obligate associations with arthropod hosts, either for dispersal (order Pyxidiophorales) or as biotrophic parasites (orders Herpomycetales and Laboulbeniales). Here, we focus on Herpomycetales and Laboulbeniales, which include fungi that form thalli, 3-dimensional, multicellular units of 1000 s of cells. Based on recently published data regarding patterns of speciation, we present the One-Host-One-Parasite model (1H1P) for haustorial thallus-forming Laboulbeniomycetes. We hypothesize that taxa with haustoria, rhizoidal structures that make contact with the host’s body cavity, have very strict host specificity. For taxa without haustoria, the microhabitat—as selected by the host—governs host shifting, presence or absence of the fungus, abundance, effective host range, and geographic distribution. We make suggestions for future research including fluorescent labeling of waxy lipids and mass spectrometry. These techniques have the potential to generate the data necessary to evaluate the here proposed 1H1P hypothesis for Herpomycetales and Laboulbeniales.

Laboulbeniomycetes: Intimate Fungal Associates of Arthropods

Arthropod-fungus interactions involving the Laboulbeniomycetes have been pondered for several hundred years. Early studies of Laboulbeniomycetes faced several uncertainties. Were they parasitic worms, red algal relatives, or fungi? If they were fungi, to which group did they belong? What was the nature of their interactions with their arthropod hosts? The historical misperceptions resulted from the extraordinary morphological features of these oddly constructed ectoparasitic fungi. More recently, molecular phylogenetic studies, in combination with a better understanding of life histories, have clearly placed these fungi among filamentous Ascomycota (subphylum Pezizomycotina). Species discovery and research on the classification of the group continue today as arthropods, and especially insects, are routinely collected and examined for the presence of Laboulbeniomycetes. Newly armed with molecular methods, mycologists are poisedto use Laboulbeniomycetes-insect associations as models for the study of a variety of basic evolutionary and ecological questions involving host-parasite relationships, modes of nutrient intake, population biology, host specificity, biological control, and invasion biology. Collaboration between mycologists and entomologists is essential to successfully advance knowledge of Laboulbeniomycetes and their intimate association with their hosts.

On the Fly: Tritrophic Associations of Bats, Bat Flies, and Fungi

Parasitism is one of the most diverse and abundant modes of life, and of great ecological and evolutionary importance. Notwithstanding, large groups of parasites remain relatively understudied. One particularly unique form of parasitism is hyperparasitism, where a parasite is parasitized itself. Bats (Chiroptera) may be parasitized by bat flies (Diptera: Hippoboscoidea), obligate blood-sucking parasites, which in turn may be parasitized by hyperparasitic fungi, Laboulbeniales (Ascomycota: Laboulbeniomycetes). In this study, we present the global tritrophic associations among species within these groups and analyze their host specificity patterns. Bats, bat flies, and Laboulbeniales fungi are shown to form complex networks, and sixteen new associations are revealed. Bat flies are highly host-specific compared to Laboulbeniales. We discuss possible future avenues of study with regard to the dispersal of the fungi, abiotic factors influencing the parasite prevalence, and ecomorphology of the bat fly parasites.

The paradoxical rarity of a fruit fly fungus attacking a broad range of hosts

Understanding the factors that determine the realized and potential distribution of a species requires knowledge of abiotic, physiological, limitations as well as ecological interactions. Fungi of the order Laboulbeniales specialize on arthropods and are typically thought to be highly specialized on a single species or closely related group of species. Because infections are almost exclusively transmitted through direct contact between the hosts, the host ecology, to a large extent, determines the distribution and occurrence of the fungus. We examined ~20,000 fruit flies (Diptera: Dacinae) collected in Malaysia, Sulawesi, Australia, and the Solomon Islands between 2017 and 2019 for fungal infections and found 197 infected flies across eight different Bactrocera species. Morphology and 1,363 bps of small subunit (18S) DNA sequences both support that the infections are from a single polyphagous fungal species Stigmatomyces dacinus-a known ectoparasite of these fruit flies. This leads to the question: why is S. dacinus rare, when its hosts are widespread and abundant? In addition, the hosts are all Bactrocera, a genus with ~480 species, but 37 Bactrocera species found sympatric with the hosts were never infected. Host-selection does not appear to be phylogenetically correlated. These results suggest a hidden complexity in how different, but closely related, host species vary in their susceptibility, which somehow limits the abundance and dispersal capability of the fungus.

Checklist of thallus-forming Laboulbeniomycetes from Belgium and the Netherlands, including Hesperomyces halyziae and Laboulbenia quarantenae spp. nov

In this paper we present an updated checklist of thallus-forming Laboulbeniomycetes (Ascomycota, Pezizomycotina), that is, the orders Herpomycetales and Laboulbeniales, from Belgium and the Netherlands. Two species are newly described based on morphology, molecular data (ITS, LSU ribosomal DNA) and ecology (host association). These are Hesperomyceshalyziae on Halyziasedecimguttata (Coleoptera, Coccinellidae) from both countries and Laboulbeniaquarantenae on Bembidionbiguttatum (Coleoptera, Carabidae) from Belgium. In addition, nine new country records are presented. For Belgium: Laboulbeniaaubryi on Amaraaranea (Coleoptera, Carabidae) and Rhachomycesspinosus on Syntomusfoveatus (Coleoptera, Carabidae). For the Netherlands: Chitonomycesmelanurus on Laccophilusminutus (Coleoptera, Dytiscidae), Euphoriomycesagathidii on Agathidiumlaevigatum (Coleoptera, Leiodidae), Laboulbeniafasciculata on Omophronlimbatum (Coleoptera, Carabidae), Laboulbeniametableti on Syntomusfoveatus and S.truncatellus (Coleoptera, Carabidae), Laboulbeniapseudomasei on Pterostichusmelanarius (Coleoptera, Carabidae), Rhachomycescanariensis on Trechusobtusus (Coleoptera, Carabidae), and Stigmatomyceshydrelliae on Hydrelliaalbilabris (Diptera, Ephydridae). Finally, an identification key to 140 species of thallus-forming Laboulbeniomycetes in Belgium and the Netherlands is provided. Based on the combined data, we are able to identify mutual gaps that need to be filled as well as weigh the impact of chosen strategies (fieldwork, museum collections) and techniques in these neighboring countries. The aim of this work is to serve as a reference for studying Laboulbeniomycetes fungi in Europe.

Laboulbeniomycetes: Evolution, natural history, and Thaxter's final word

Historically, thallus-forming Laboulbeniomycetes, including the orders Laboulbeniales and Herpomycetales, were set apart because of their distinctive morphology and ecology. Although some biologists correctly interpreted these arthropod ectoparasites as fungi, even ascomycetes, others thought they were worms, red algae, or members of taxa described especially for them. Speculation on the evolution of the group involving red algae, the morphology-based Floridean Hypothesis, persisted deep into the 20th century, in part because valid alternatives were not presented. Although the distinctive features of Laboulbeniales clearly set them apart from other fungi, the difficulty was in the absence of characters grouping them among the fungi. Thaxter considered the Laboulbeniales to be ascomycetes, but he avoided phylogenetic discussions involved in the Floridean Hypothesis all of his life. Eventually, developmental studies of the life history of Pyxidiophora species, hyphal perithecial ascomycetes with 2-celled ascospores, revealed characters connecting Laboulbeniales to other ascomycetes. The distinctive morphological features of Laboulbeniales (absence of mycelium, a thallus developed from 2-celled ascospores by cell divisions in several planes, arthropod parasitism) can be best understood by comparison with Pyxidiophora. The development of a 3-dimensional thallus composed of true parenchyma occurs not only in Laboulbeniales, but also in Pyxidiophora species. The life history of arthropod ectoparasitism of Laboulbeniales as well as mycoparasitism and phoretic dispersal by arthropods of Pyxidiophora species can be explained by Tranzschel's Law, originally applied to rust fungi. Molecular analyses including other arthropod-associated fungi have contributed to a better understanding of an enlarged class, Laboulbeniomycetes, which now includes a clade comprising Chantransiopsis, Tetrameronycha, and Subbaromyces. A two-locus phylogenetic tree highlights evolutionary and life history questions with regard to the placement of Herpomycetales as the first diverging lineage of the Laboulbeniomycetes. The sister group for all the Laboulbeniomycetes remains to be discovered.

Effects of fungal infection on the survival of parasitic bat flies

Background

Parasites are able to alter numerous aspects of their hosts’ life history, behaviour and distribution. One central question in parasitology is to determine the degree of impact that parasites have on their hosts. Laboulbeniales (Fungi: Ascomycota) are ectoparasitic fungi of arthropods. Even though these fungi are widely distributed, little is known about their ecology and their possible physiological effects on their hosts. We used a highly specific bat fly-fungi association to assess the effect of these fungal parasites on their dipteran hosts.

Methods

We collected bat flies (Diptera: Nycteribiidae) belonging to two species, Nycteribia schmidlii and Penicillidia conspicua from their bat host Miniopterus schreibersii (Chiroptera: Miniopteridae). We experimentally tested the effect of infection on the lifespan of bat flies.

Results

The prevalence of Laboulbeniales fungi was 17.9% in N. schmidlii and 64.8% in P. conspicua. Two fungi species were identified, Arthrorhynchus eucampsipodae and A. nycteribiae, both showing strict host specificity with N. schmidlii and P. conspicua, respectively. We found that fungal infection reduced by half the survival rate of P. conspicua regardless of sex, whereas N. schmidlii was not affected by the infection. Moreover, the intensity of infection showed negative correlation with the lifespan of P. conspicua.

Conclusions

To our knowledge, this is the first indication that fungal infection can alter bat fly survival and thus may play a significant role in the population dynamics of these bat ectoparasites.

Hyperparasitism in caves: Bats, bat flies and ectoparasitic fungus interaction

Bat flies (Diptera: Nycteribiinae) are highly specialized bloodsucking bat ectoparasites. Some of the ectoparasitic bat flies are themselves parasitized with an ectoparasitic fungus of the genus Arthrorhynchus (Laboulbeniales). Ascospores of the fungus attach to the cuticle of a bat fly and develop a haustorium that penetrates the host cuticle. This interaction defines the fungus as a hyperparasite. Both the fly and the fungus are obligate parasites and this peculiar case of hyperparasitism has remained largely unstudied. We studied the prevalence of Laboulbeniales, genus Arthrorhynchus, in natural populations of bat flies infesting the bat species Miniopterus schreibersii, Myotis bechsteinii, My. blythii, My. daubentonii, My. escalerai and My. myotis in Portuguese caves. Laboulbeniales were found infecting 10 of the 428 screened bat flies (2.3%) in natural populations, with fewer infections in winter. Images obtained with transmission electron microscopy show the fungal haustorium within the bat fly host tissue, from where it extracts nutrition.

Bats, Bat Flies, and Fungi: A Case of Hyperparasitism

Bats are parasitized by numerous lineages of arthropods, of which bat flies (Diptera, Nycteribiidae and Streblidae) are the most conspicuous. Bat flies themselves can be parasitized by Laboulbeniales, fungal biotrophs of arthropods. This is known as hyperparasitism, a severely understudied phenomenon. Three genera of Laboulbeniales occur on bat flies: Arthrorhynchus on Nycteribiidae, Gloeandromyces and Nycteromyces on Streblidae. In this review we introduce the parasitic partners in this tripartite system and discuss their diversity, ecology, and specificity patterns, alongside some important life history traits. Furthermore, we cover recent advances in the study of the associations between bat flies and Laboulbeniales, which were neglected for decades. Among the most immediate needs for further studies are detailed tripartite field surveys. The vermin only teaze and pinch Their foes superior by an inch So, naturalists observe, a flea Has smaller fleas that on him prey; And these have smaller still to bite 'em, And so proceed ad infinitum. Jonathan Swift (On Poetry: A Rhapsody, 1733).

Studies on Dimorphomyceteae: I. New species of Nycteromyces and Dimeromyces (Laboulbeniales) on bat flies (Streblidae)

Three new species, Nycteromyces orientalis, Dimeromyces capensis, and D. streblidarum, belonging to the Laboulbeniales (Fungi, Ascomycota) and collected on bat flies (Diptera, Streblidae), are described and illustrated. The new species of Nycteromyces is the second described in this rarely collected genus, with the type species, N. streblidinus, previously collected only three times from Venezuela, Panama, and Honduras. The material for our new species comes from Australia, India, Philippines, and Tanzania, and morphological characters of these new collections require emendation of the original generic diagnosis. The distribution of N. streblidinus is also extended with additional collections from Costa Rica and Peru. We describe two new species of Dimeromyces from streblid hosts, the first report of any members of this large, diverse genus on this host family. Newly described taxa are compared with known species and the genera Nycteromyces and Dimeromyces discussed in relation to other known Laboulbeniales taxa.

Laboulbeniales (Fungi: Ascomycota) infection of bat flies (Diptera: Nycteribiidae) from Miniopterus schreibersii across Europe

BACKGROUND

Bat flies (Diptera: Nycteribiidae and Streblidae) are obligate, blood-sucking ectoparasites of bats with specialized morphology, life-cycle and ecology. Bat flies are occasionally infected by different species of Laboulbeniales (Fungi: Ascomycota), microscopic fungal ectoparasites belonging to three genera: Arthrorynchus spp. are restricted to the Eastern Hemisphere, while species of Gloeandromyces and Nycteromyces occur on Neotropical bat flies. Little is known about the distribution and host specificity of Arthrorynchus spp. on bat flies. In this study, we focused on sampling bat flies from the cave-dwelling bat species Miniopterus schreibersii. Bat and ectoparasite collection took place in Albania, Croatia, Hungary, Italy, Portugal, Slovakia, Spain and Switzerland. Flies were inspected for Laboulbeniales infections.

RESULTS

Six hundred sixty seven bat flies of five species were collected: Nycteribia latreillii, N. pedicularia, N. schmidlii, Penicillidia conspicua, and P. dufourii. Laboulbeniales infection was observed on 60 specimens (prevalence = 9%). Two Laboulbeniales species, Arthrorhynchus eucampsipodae and A. nycteribiae, were present on three bat fly species. All observations of A. eucampsipodae were on N. schmidlii, and A. nycteribiae was present on P. conspicua and P dufourii. Arthrorhynchus eucampsipodae is, for the first time, reported from Slovakia and Spain. Arthrorhynchus nycteribiae represents a new country record for Portugal and Slovakia. There were no significant differences among infection rates in different countries. Females of N. schmidlii showed a higher infection rate than males with an observable trend (P = 0.0502). No sex differences in infection rate for P. conspicua and P. dufourii were detected. Finally, thallus density was significantly lower in N. schmidlii compared to P. conspicua and P. dufourii.

CONCLUSIONS

With this study, we contribute to the knowledge of the geographical distribution and host specificity of Laboulbeniales fungi associated with ectoparasitic bat flies within Europe. We discuss parasite prevalence and host specificity in the light of our findings and the available literature. Penicillidia conspicua is unambiguously the main host species for A. nycteribiae based on our and previous findings. Differences in parasite intensity and sex-biased infections of the fungi are possible depending on the species.

The effects of fungal infection and physiological condition on the locomotory behaviour of the ant Myrmica scabrinodis

Parasite infection often results in alterations in host behaviour. These changes vary greatly in their magnitude, from slight shifts in the time spent by the host performing a given activity to the appearance of novel behaviours. The effects of parasites can differ with the age and the physiological condition of the host. Rickia wasmannii is an ectoparasitic fungal symbiont in Myrmica ants that covers the whole body surface of the host and reduces its lifespan. The fungus is present in both young and old individuals, making it an optimal subject for the study of age-related parasitic effects. We tested the effect of fungal infection on the locomotory activity of the Myrmica scabrinodis ant in different age categories. The fat content of workers was measured as a proxy for their physiological status. Based on our findings, old workers bore more thalli and were leaner than young individuals, while they tended to move at higher speeds and with a lower degree of meandering. Young individuals covered smaller distances, at slower speeds and with a higher degree of meandering. Contrary to our expectations, the infection intensity of R. wasmannii affected neither the fat content nor the locomotory activity of ant workers. However, the two age classes seem to have different strategies with regards to the relationship between fat content and distance covered. Our results suggest that characteristics of locomotory activity differ between the age classes in many respects, and are also influenced by their physiological status, but parasitism by R. wasmannii does not seem to have a straightforward effect on any of the variables studied.

Fireworks under the microscope: a spectacular new species of Zodiomyces from the Thaxter collection

A new species of Zodiomyces (Ascomycota, Laboulbeniales) is described, Z. rhizophorus, parasitic on a hydrophilid beetle (Coleoptera, Hydrophilidae) from Trinidad. This species was discovered during the examination of the slides of Laboulbeniales made by Roland Thaxter. It is characterized by numerous long, slender, multicellular and multiseriate outgrowths at the base of the receptacle. Thaxter's outstanding illustrations have set a standard in the field of mycology; we provide a review of the methods he employed in the preparation of these illustrations.

Distribution of the myrmecoparasitic fungus Rickia wasmannii (Ascomycota: Laboulbeniales) across colonies, individuals, and body parts of Myrmica scabrinodis

The ant species Myrmica scabrinodis plays a markedly important ecological role through much of the humid grasslands of Eurasia. It hosts a species-rich community of pathogens and parasites, including Rickia wasmannii, an enigmatic member of entomoparasitic laboulbenialean fungi. This study provides a descriptive ecology of R. wasmannii by characterizing its prevalence and distribution across several hierarchical levels: colonies, individuals, and anatomic body parts. Infections were restricted to a single ant species, M. scabrinodis, and infected colonies occurred predominantly in wet habitats. Infections tended to be highly prevalent within infected colonies, often reaching 100% sample prevalence among workers. Individual infections exhibited an aggregated distribution typical to host-parasite systems. Workers from the aboveground part of nests (presumably older ones acting as foragers) were more infected than those from the belowground part. Fungal thalli could be found all over the body of the hosts, the head and the abdomen being the most infected parts of the body. The fungi's distribution among host body parts statistically differed between low versus high-intensity infections: the initial dominance of the head decreased with advancing infection. These findings may provide baseline data for future comparative or monitoring studies.

Studies on interesting species of the laboulbeniales collected from Korea

Five species of the Laboulbeniales, including two unrecorded species are reported from South Korea. They are as follows; Dioicomyces anthici Thaxter on Anthicus confucii Marseul, Laboulbenia melanaria Thaxter on Anisodacthius tricuspidatus Morawitz, L. philonthi Thaxter on Philonthus wuesthoffi Bernhauer, Peyritschiella japonicus Terada on Philonthus japonicus Sharp, and Scaphidiomyces baeocerae Thaxter on Scaphisoma unicolor Achard. Among these species, L. melanaria Thaxter, S. baeocerae Thaxter and the male thallus of D. anthici Thaxter are newly described from South Korea. L. Philonthi Thaxter and P. japonicus Terada are newly collected in some places where were unlike with the examined region ago.

A new species of the genus euphoriomyces (laboulbeniales ascomycotina) collected in Korea

One new species of the genus Euphoriomyces was collected on Scaphisoma rufum Achard (Scaphidiidae) in South Korea. Euphoriomyces chaekyui sp. nov. is unique in having a single terminal phialide shaped an elongated cylindrical form on the distal portion of the main axis.

A new species of the genus coreomyces (laboulbeniales ascomycotina) collected from the island of java, indonesia

One new species of the genus Coreomyces was collected on Micronecta sedula from the island of Java; C. javanicus sp. nov. is very similar to and apparently closely related to C. corixae. This species is characterized by a receptacle that is bent towards one side with cell I, nearly rounded. The length of cell I is equal to that of cell II and the perithecia are longitudinal, elliptical or cylindrical. Thalli consistently occurred on the margin of the left elytron of the hosts.

Notes on species belonging to the genus coreomyces (laboulbeniales) collected from java island, indonesia

Four species of Laboulbeniales collected from Java Island, Indonesia between August and September in 2006 are described. These species, which belong to the genus Coreomyces and were found on the family Corixidae of the order Hemiptera, were as follows; Coreomycus corixae Thaxter, Coreomyces micronectae Thaxter and Coreomyces orientalis Thaxter, which were found on Micronecta sedula Horvath, and Coreomyces recurvatus Thaxter, which was found on Micronecta sedula Horvath and Xenocorixa sp. C. corixae Thaxter and C. orientalis Thaxter were originally found on Micronecta, whereas C. recurvatus Thaxter was originally found on Xenocorixa. All species described herein are new to Java Island. The specimens were deposited in the Biological Herbarium, Division of Science Education, College of Education, Chosun University.

Notes on two species of the laboulbeniales from tibet

Two species of the Laboubeniales based on the Tibetan collections are described. They are new to the mycological flora of Tibet. Laboulbenia polyphaga found on several parts of Amara majuscula was characterized by having the outer appendages not ramified and simple. Peyritschiella protea obtained on the lower abdomen of Philonthus wuesthoffi, had two perithecia and two antheridia produced on the third layer of receptacle.

Notes on three species of the laboulbeniales newly collected in Korea (2005)

Three species of the Laboubeniales from Korea are described. They are new to the mycological flora of Korea. Corethromyces purpurascens on several parts of Ochthephilum densipenne, Laboulbenia barbara on the metasternum of Philonthus longicornis and L. compressa on the elytra of Harpalus tinctulus were found.