Researchers have identified a previously undescribed microsporidian associated with Cydalima perspectalis, the box tree moth, in larvae collected in Bilecik, Türkiye. They describe it as Vairimorpha aylae sp. n., a new species in the genus Vairimorpha. The finding comes from a laboratory study that combined light microscopy, transmission electron microscopy and molecular phylogenetic analysis. Together, those approaches gave the researchers evidence from the organism’s visible form, its fine internal structure and its SSU rDNA sequence, a genetic marker used in the analysis.
The microscopic signature
Giemsa-stained spores measured 4.22 plus or minus 0.24 micrometres in length and 2.48 plus or minus 0.24 micrometres in width. The measurements are reported in micrometres, a unit used for microscopic structures. The supplied analysis does not specify what the plus-or-minus figures represent statistically, so they should be read simply as the measurements reported by the authors.
Transmission electron microscopy, used to examine structures at much finer detail, found that the mature spore wall measured 145 nanometres plus or minus 46.04 nanometres. It consisted of a clear, thick endospore measuring 119.4 plus or minus 38.12 nanometres and an electron-dense, uniform, thin exospore measuring 31.67 plus or minus 5.16 nanometres. The spores also contained a coiled internal structure called an isofilar polar filament, with 15 to 17 coils and a diameter of 89.6 plus or minus 9.64 nanometres. The analysis did not specify the statistical meaning of the plus-or-minus values.
A name supported by several clues
The researchers did not base the identification on appearance alone. They examined larvae for pathogens with light microscopy and transmission electron microscopy, then used molecular phylogenetic analysis to confirm the microscopy findings. The resulting SSU rDNA phylogenetic tree supported the morphological and ultrastructural characteristics. On that combined evidence, the authors interpret the organism as a new Vairimorpha species.
What the evidence does not tell us
The result is a taxonomic description, not a test of the pathogen’s effects. The study reports a microsporidian associated with Cydalima perspectalis, but the supplied analysis does not report prevalence, geographic distribution beyond Bilecik, host survival, development, reproduction, transmission or population-level suppression. It therefore does not establish that infection is lethal, reduces the moth’s fitness, or can be used effectively for biological control. The work identifies a candidate for future research while leaving those practical questions open.
The authors also state that no protists or microsporidian pathogens had been isolated from natural Cydalima perspectalis populations to date. The supplied review treats that as an author-reported statement that was not independently verifiable here, so it should not be read as a settled account of all earlier observations.
Further work would need to establish how common Vairimorpha aylae is and where it occurs, and whether infection affects the moth’s survival, development, reproduction or population density. Researchers would also need to clarify transmission and test whether the pathogen could be used effectively for biological control. Those questions are separate from naming and describing a species, and the present report does not answer them.
The study was financially supported by the Scientific and Technological Research Council of Türkiye under project 221O401. The authors declare no conflict of interests. The paper states that no datasets were generated or analysed during the study, and that no ethical approval was required. It was accepted on 10 August 2026 and published as the version of record on 21 August 2026.
Paper data and sources
Original title: Vairimorpha aylae sp. nov. (Microsporida, Nosematidae), a New Microsporidian Pathogen of the Box Tree Moth, Cydalima perspectalis (Walker, 1859) (Lepidoptera, Crambidae).
Authors: Mustafa Yaman, Tuğba Sağlam Güvendİk
Journal/Repository: Acta parasitologica
Status: Peer-reviewed
First online: 2026-08-21
DOI: 10.1007/s11686-026-01379-x
Original paper · Full text