Museum collections reveal a global range of Ophryocystis parasites in Danaus butterflies

Understanding the host range, patterns, and consequences of parasite infection is essential for detecting and responding to parasite-mediated insect declines. The debilitating protozoan Ophryocystis elektroscirrha (OE; Neogregarinorida: Ophryocystidae) was identified as a parasite of monarch (Danaus plexippus) and queen (D. gilippus) butterflies in the late 1960s in Florida, USA. Recently, similar parasites were identified in other Danaus species, but their occurrence among the diverse clade of milkweed butterflies (Nymphalidae: Danainae) remains unexplored. This study used museum collections to systematically investigate the host range and global occurrence of OE and similar Ophryocystis parasites in milkweed butterflies. We examined 2,727 museum specimens from 86 countries/areas, spanning 61 milkweed butterfly species across 10 genera, to document parasitism. Our findings revealed that, among milkweed butterflies, Ophryocystis parasites were confined to hosts in the genus Danaus ..., We used archived specimens to determine infection status and the temporal and geographic infection patterns among milkweed butterflies. Butterfly species targeted were milkweed butterflies in the subfamily Danainae. We recorded the specimen information from its label. Pictures of the dorsal side of each pinned specimen were taken. When no species information was included on the specimen’s label, pictures were used for identification. A subset of pictures alongside label information was shared with an expert on milkweed butterfly taxonomy for identification or confirmation. We followed Ackery and Vane-Wright (1984) to standardize the taxonomic nomenclature and resolve synonyms at the species level except where more recent taxonomic work was available. Specimens were swabed and screened for the presence of spores of OE and morphologically similar parasites. We used digital photographs to estimate the forewing length (mm) of a subset of parasite-positive and negative specimens. We also est..., , # Museum collections reveal a global range of *Ophryocystis* parasites in *Danaus* butterflies

[https://doi.org/10.5061/dryad.t76hdr88p](https://doi.org/10.5061/dryad.t76hdr88p)

## Description of the file structure

Data and code to accompany the research article \"Museum collections reveal a global range of *Ophryocystis* parasites in *Danaus* butterflies\". All necessary files to perform the analysis are included. The code is written in the R language.

| File | Description |
| :-------------------------------------------------- | :------------------------------------------------------------------------------------------ |
| Museums\_butterfly\_parasites\_data\_dictionary.csv | Data dictionary describing the variables for each of the three CSV data files included here |
| museums\_butterfly\_parasites\_data.csv | Data for each museum specimen sampl...