Oedemeridae

Distinguished from similar soft-bodied beetles by the combination of: long filiform antennae; pronotum lacking lateral edges and narrower than elytra; heteromerous tarsi with bilobed penultimate segment; open procoxal cavities behind; and conical contiguous procoxae. Can be separated from Meloidae (true blister beetles) by the more slender body form, different antennal structure, and tarsal formula. The soft elytra and flower-visiting habits may cause confusion with some Cerambycidae, but the short antennae relative to body length and different tarsal structure distinguish Oedemeridae.

Adults are found predominantly on flowers and foliage in diverse terrestrial habitats including forests, woodlands, grasslands, and coastal areas. Larval habitats vary by genus: most develop in spongy, damp, decomposing wood, while larvae of Oedemera and Stenostoma develop in dead stems of herbaceous plants. Some species, notably Nacerdes melanura (wharf borer), inhabit wet wood in coastal areas and the tidal zone.

Cosmopolitan distribution with species recorded from all major biogeographic regions. Well-represented in North America, Europe, Africa, Asia, and Australia. The family shows particular diversity in Mediterranean climates and temperate regions.

In temperate regions, adults are primarily active during spring and summer months and are diurnal. In tropical regions, most species are nocturnal and attracted to light. Activity patterns correlate with flowering periods of host plants.

Adults are primarily pollen and nectar feeders, described as polyphagous on floral resources. The family has been referred to as "pollen-feeding beetles" based on this habit. Larvae are xylophagous, feeding on decaying wood or herbaceous plant stems.

• Dracaena draco - larval hostNacerdochroa concolor is a pest of dragon-tree
• decaying wood - larval habitatMost genera develop in spongy, damp, decomposing wood
• herbaceous plant stems - larval habitatLarvae of Oedemera and Stenostoma develop in dead stems
• wet coastal wood - larval habitatNacerdes melanura larvae bore into wet wood in coastal areas and tidal zones

Complete metamorphosis with egg, larval, pupal, and adult stages. Larvae of most genera are xylophagous and bore tunnels in decomposing wood. Larval development occurs within the substrate, with pupation taking place in the feeding galleries. Adults emerge and disperse to flowers. The wharf borer (Nacerdes melanura) has larvae that can tolerate submersion by seawater in tidal zone wood.

Adults are active on flowers where they feed on pollen and nectar. Temperate species are diurnal, while tropical species are predominantly nocturnal and attracted to light. Adults possess chemical defense: they contain cantharidin in their body fluids, making them unpalatable to predators. This is often advertised through aposematic (warning) coloration. Adults are capable of flight and are commonly encountered on diverse flowering plants.

Adults function as pollinators through their pollen-feeding activities on flowers. Larvae contribute to wood decomposition as xylophages in decaying wood and plant stems. The family serves as a food source for specialized predators able to tolerate cantharidin. Chemical defense via cantharidin production represents a significant example of convergent evolution with Meloidae.

Generally of minor economic importance. Most species are benign decomposers with no significant impact. One exception is Nacerdes melanura (wharf borer), whose larvae damage docks, wharves, and pilings in coastal areas by boring into wet wood. Cantharidin produced by adults has historical use in traditional medicine and has been investigated for anti-cancer properties, though the family is not commercially exploited for this compound.

• MeloidaeBoth families produce cantharidin and have soft bodies, but Meloidae have different body proportions, shorter antennae, and different tarsal structure
• CerambycidaeSome flower-visiting cerambycids share habitat with Oedemeridae, but have much longer antennae and hard elytra
• CantharidaeSoldier beetles also have soft elytra and visit flowers, but have different body shape and lack the distinctive pronotal and tarsal characters of Oedemeridae

The common name "false blister beetles" reflects historical confusion with Meloidae (true blister beetles) due to shared cantharidin production and soft bodies, but the families are not closely related. Some recent authors have advocated for "pollen-feeding beetles" as a more accurate common name reflecting the actual biology of adults.

• beetle
• pollen-feeding
• chemical defense
• cantharidin
• wood-boring larvae
• flower visitor
• cosmopolitan

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Oedemeridae | Beetles In The Bush
• What Puts the Blister Into Blister Beetles?
• Eumastacidae | Beetles In The Bush
• Cimbicidae | Beetles In The Bush
• Revision of the Southern African Oedemeridae (Coleoptera, Tenebrionoidea)
• Notes on the Life History of Ditylus Quadricollis LeConte (Oedemeridae)
• Identification et répartition des espèces françaises d'Ischnomera (Coleoptera Oedemeridae)
• On the taxonomy of the dityline genera Diasclera Reitter, Dityloidea Fairmaire and Germain and Nerdanus Fairmaire (Coleoptera: Oedemeridae)
• Nacerdochroa concolor (Brull? 1839) (Coleoptera: Oedemeridae): taxonomy, ecology, life cycle and larval instars
• New report of Calopodinae (Coleoptera, Oedemeridae) in South Korea, with description of a new species of the genus Sparedrus Dejean, 1821.