The scale of the underlying effort is remarkable. Researchers examined specimens held in more than twenty Swiss natural history collections, from the Naturhistorisches Museum Basel to the Museo cantonale di storia naturale in Lugano, alongside private collections maintained by professional and amateur entomologists. Roughly 42 percent of the compiled occurrences came from museum specimens, 5 percent from published literature, and 53 percent from other sources including volunteer observers, research institutes, and ecology offices. Every record was scrutinized against strict criteria before a species could be admitted to the national list.

That scrutiny proved decisive. Several historic Swiss collections, notably those assembled by Charles Maerky and Max Täschler, have long been regarded as problematic because they contain specimens whose original labels cannot be trusted. Records traced to these collections were systematically excluded, along with species cited in nineteenth-century catalogs without any supporting specimens, misidentified material, and isolated introductions of nonindigenous species that never established breeding populations. The authors applied an eight-point rubric of doubt, flagging records whose data sources could not be verified, whose identifications were wrong, or whose localities were confused with foreign place names sharing the same spelling.

The taxonomy itself has shifted beneath the checklist. Until 2015, the superfamily Coccinelloidea was folded inside Cucujoidea, when a major phylogenetic revision recognized the two as distinct lineages. Switzerland now hosts eight families within Coccinelloidea and ten within Cucujoidea, spanning an extraordinary range of ecological strategies. Among them are the Latridiidae, or minute brown scavenger beetles, which alone account for 77 of the 183 confirmed species, and the Monotomidae, slender root-eating beetles represented by 22 species. Several families had not received a national treatment in more than a century, with the last comprehensive catalogs dating to 1867 and 1900.

Fourteen species appear on the Swiss list for the first time. Among the Erotylidae, the pleasing fungus beetles Triplax collaris and Triplax elongata were captured only in recent years, the former in two northern localities since 2021 and the latter in beech forests of Ticino between 2019 and 2020. The Latridiidae contributed the largest share of newcomers, including Corticaria alleni, first found in 2016 in a thermophilic Alpine pine forest, and Corticaria interstitialis, a boreoalpine species so rare that a single male trapped in 2025 in an unmanaged high-altitude coniferous forest constituted its entire Swiss record. Melanophthalma rhenana, a species only described in 2007, was detected in Geneva and Ticino from 2019 onward.

Several of these newcomers share a telling ecological profile. Species such as Corticaria interstitialis, Latridius brevicollis, and Teredus opacus are classified as primeval forest relicts in Europe, organisms whose exacting requirements for old-growth conditions, continuous dead wood, and specific fungal associates make them among the first casualties of intensive forestry. Their appearance in Switzerland, often through the increasing use of flight interception traps placed in near-natural forests, suggests that remnant pockets of ancient woodland structure persist in the Alps and the southern lowlands, harboring fauna thought to have vanished from much of Central Europe.

The removals are equally instructive. Stephostethus lardarius, a hygrophilous species common in neighboring Germany and France, was struck from the Swiss list because every specimen labeled as Swiss traced back to the problematic Maerky collection. Pediacus fuscus, a Holarctic species with a distinctly northern distribution, had been cited for Switzerland since 1867, yet no supporting specimen exists in any examined collection, confirming a hypothesis first advanced in 1960. The myrmecophilous beetles Cholovocera formicaria and Merophysia formicaria, which live exclusively in ant nests of Mediterranean species absent from Switzerland, were excluded on both distributional and ecological grounds.

Not every exclusion is permanent. The authors note that Corticaria corsica, known from Corsica and southern France, could plausibly occur in Switzerland but awaits confirmation. Cryptolestes capensis, a cosmopolitan grain pest, was trapped once in the wild in Aargau in 2015 but withheld from the list until breeding in nature can be demonstrated. Similarly, Cartodere satelles, an Australian native recorded in Europe only in scattered introductions, was documented from a single 1954 specimen and set aside pending evidence of establishment.

Some species blur the boundary between native and introduced. The minute scavenger beetle Cartodere bifasciata, native to Australia and first described from a specimen found in German tobacco, has been observed regularly in Switzerland since 1984, almost exclusively in natural settings such as leaf litter and compost, and is now considered established. Corticarina cavicollis, another Nearctic arrival first documented in Europe in 1998, was found in 2023 beating oak branches in southern Ticino, where two specimens suggest naturalization. Migneauxia lederi, a cosmopolitan contaminant of stored rice and tea, now appears to reproduce and overwinter outdoors in Switzerland.

The checklist also documents species at the edge of their range. Anommatus besucheti, A. dentatus, and A. scherleri are known only from Switzerland and Italy, while A. ticinensis appears restricted to a single locality in southern Ticino, where seven specimens were found by sifting leaf litter in 1969. Triplax scutellaris, first recorded in Switzerland in 2015, has since been captured in both a lowland beech forest and a spruce stand at 1,580 meters, hinting at broader ecological flexibility than previously assumed. Tritoma subbasalis, known from just two specimens collected in Grisons in 1997, represents the westernmost extent of its entire distribution.

Climate change looms over the analysis. The authors note that Rhizophagus grandis, a predator deployed across Europe since the 1980s for the biological control of the spruce bark beetle Dendroctonus micans, has expanded markedly in Switzerland and is expected to benefit further as warming weakens spruce stands and favors its prey. Southern species may follow the same trajectory northward, while cosmopolitan biocontrol agents could appear in the fauna. The checklist provides the baseline against which such shifts will be measured.

For the researchers, the work represents a further step toward a comprehensive understanding of the entire Swiss beetle fauna, a project that has already produced revised treatments of other families in recent years. All validated data have been transmitted to GBIF, the global biodiversity information facility, and updated distribution maps are available through the Swiss info fauna cartographic server. Four families, including the Corylophidae, Cryptophagidae, Nitidulidae, and Phalacridae, remain to be updated in future publications, promising further revisions to a fauna that continues to yield surprises more than 150 years after the first national catalog appeared.

Subject of Research: An annotated checklist of Coccinelloidea and Cucujoidea beetle families in Switzerland based on museum specimens and literature records

Article Title: Annotated checklist of the Coccinelloidea (partim) ( Alexiidae , Bothrideridae , Cerylonidae , Endomychidae , Latridiidae , Teredidae ) and Cucujoidea (partim) ( Cucujidae , Erotylidae , Laemophloeidae , Monotomidae , Phloeostichidae , Silvanidae , Sphindidae ) of Switzerland ( Coleoptera )

Article References: Annotated checklist of the Coccinelloidea (partim) ( Alexiidae , Bothrideridae , Cerylonidae , Endomychidae , Latridiidae , Teredidae ) and Cucujoidea (partim) ( Cucujidae , Erotylidae , Laemophloeidae , Monotomidae , Phloeostichidae , Silvanidae , Sphindidae ) of Switzerland ( Coleoptera ). (n.d.). https://doi.org/10.3897/alpento.10.182286

Image Credits: AI Generated

DOI: 10.3897/alpento.10.182286

Keywords: beetles, Switzerland, checklist, Coccinelloidea, Cucujoidea, biodiversity, entomology, saproxylic species, primeval forest relicts, Latridiidae, Erotylidae, species records