Ferenc Báthori

Rickia wasmannii increases the need for water in Myrmica scabrinodis (Ascomycota: Laboulbeniales; Hymenoptera: Formicidae)

The order Laboulbeniales (Fungi, Ascomycota) is a little-studied group of microscopic ectoparasites of invertebrates, mostly insects. The effects of Laboulbeniales species on their hosts are mostly unknown. Rickia wasmannii Cavara, 1899 is a common Laboulbeniales fungus occurring in Europe and is currently known to be a parasite of at least eight Myrmica ant species. R.wasmannii serves as a good model organism for Laboulbeniales-host interactions, as this species covers the host in a very high density, and infected host individuals can be easily collected in high numbers. The effect of R. wasmannii on the survival rate of its most common host species, Myrmica scabrinodis Nylander 1846, was therefore investigated in a laboratory experiment on an individual level. To enhance the results, environmental stresses were simulated by depriving infected and uninfected workers of water and food. The survival of individuals was recorded hourly until the death of the last individual. Infected specimens were significantly more sensitive to the withdrawal of food and water than uninfected specimens. When we tested for water consumption, we found that infected ants spent more time consuming water than uninfected ants. Therefore, it is possible that infected ants must replace the loss of water. Based on these results, R. wasmannii substantially decreases the chances and time of survival of infected individuals, at least in resource-limited environments, which suggest that R. wasmannii has a negative effect on its host.

Studies of Laboulbeniales on Myrmica ants (III): myrmecophilous arthropods as alternative hosts of Rickia wasmannii

Myrmecophilous arthropods and their manifold relations to host ants are interesting from an evolutionary perspective. Rickia wasmannii is an ectoparasitic fungus belonging to the Laboulbeniales order. Here, we show that inquiline mites can become infected by R. wasmannii, which was thought to be restricted to the genus Myrmica (Hymenoptera: Formicidae). This is the first report of R. wasmannii from an alternative host in another subphylum (Chelicerata). We also found immature fruiting bodies on a larva of Microdon myrmicae (Diptera: Syrphidae), which represents the first report of any Rickia species on flies. This fungus is capable of infecting alternative, unrelated host species as they co-occur in the ant nest “microhabitat”. These observations provide direct evidence for ecological specificity in Laboulbeniales. The presence of R. wasmannii on inquilines in Myrmica ant nests suggests that the parasite may have adapted to the ant nest environment and is less dependent on acquiring specific nutrients from the hosts. However, the alternative cannot be excluded; these infections might also represent chance events if the fungus is incapable of fulfilling its life cycle.

First Central European record of the fungus Prolixandromyces triandrus Santam. (Ascomycota: Laboulbeniales), a parasite of veliid bugs (Heteroptera: Veliidae), with notes on its biology and DNA barcoding

ABSTRACT A new distribution record for Prolixandromyces triandrus Santam. (Ascomycota: Laboulbeniales) is presented from the Bükk Mountains in northeastern Hungary, from the host species Velia (Plesiovelia) saulii Tamanini, 1947 (Heteroptera: Veliidae). Hitherto, this fungal parasite had only been observed in the western Mediterranean region and the Macaronesia Archipelago. Prolixandromyces. triandrus seems to be abundant in the reported Hungarian host population. Additionally, ribosomal DNA barcodes for this fungal species are also presented. Incidence of the parasite and potential of the molecular investigations of host-parasite relationships of this ectoparasitic fungus is discussed. A brief review is given of known hosts of P. triandrus and of Laboulbeniales from aquatic/semiaquatic insect hosts in Hungary.