Checkered Beetles (Cleridae)
CLERIDAE – MORPHOLOGY, ECOLOGY, AND GLOBAL DISTRIBUTION
Checkered beetles (Cleridae; from Greek kleros “lot” or “chance,” likely referring to their variegated coloration) form a cosmopolitan family within the superfamily Cleroidea, comprising over 3,000 described species worldwide. In Europe, approximately 200 species are recorded, with roughly 60 species occurring in the Czech Republic. Adult sizes range from 3 to 25 mm. These beetles exhibit an elongate, soft-bodied morphology with vividly patterned elytra, often adorned with red, yellow, black, or blue maculations and stripes, which serve as aposematic (warning) coloration against potential predators.
Wikipedia
The head is large with prominent compound eyes, and antennae are filiform or serrate, occasionally clavate in certain genera. Legs are elongated and cursorial, enabling rapid movement across bark surfaces. Both larvae and adults are predatory, primarily feeding on other insects. Adults display agile flight, visiting flowers or decaying wood, and some genera exhibit remarkable dispersal capabilities.
DISTRIBUTION AND SPECIES IN THE CZECH REPUBLIC
In the Czech Republic, common representatives include the ant-mimicking Clerus formicarius (7–10 mm, red-and-black), the larger Clerus mutillarius, and the bee-associated Trichodes apiarius, which preys on bee larvae. Noteworthy species also include Tillius elongatus, typically found on beech wood, and the rare Aporthopleura sanguinicollis, critically endangered in southern Europe including the Czech Republic. Cleridae predominantly occupy the Palearctic and Holarctic regions, favoring temperate forests, orchards, and dry slopes. Globally, clerids exhibit their greatest species richness in tropical and subtropical forests, with some taxa specialized for saproxylic habitats in tropical rainforests or arid woodland ecosystems.
ECOLOGY AND HABITAT PREFERENCES
Checkered beetles inhabit deciduous and coniferous forests, stumps, tree cavities, beehives, and flowers. Adults prey on smaller insects such as wasps, bees, and wood-boring larvae. Their activity is thermophilic, peaking in spring through autumn. Adults are attracted to pollen and nectar, which may supplement their diet. Larvae develop within dead, decaying, or insect-infested wood, preying on the larvae of other beetles, termites, or lepidopteran larvae, and in some cases consuming fungal mycelia. Through their predation, they contribute to natural biological control of forest pests and enhance tree health.
LARVAL BIOLOGY
Clerid larvae are elongate, agile predators, reaching up to 20 mm. They reside under bark or within wood galleries, hunting larvae of cerambycids, buprestids, and other wood-associated insects. Development typically spans 1–2 years, sometimes occurring in aggregations. Certain larvae possess wing-like appendages facilitating rapid locomotion. Depending on the species, they exhibit saprophagous or carnivorous feeding strategies, sometimes consuming fungal hyphae.
REPRODUCTION AND LIFE CYCLE
Females oviposit into wood crevices, hives, or beneath bark from April to July. Eggs hatch within 1–2 weeks, and larvae develop for 1–3 years depending on species, habitat, and climate. Pupation occurs in chambers lined with frass, and adults emerge primarily in spring. The complete life cycle ranges from 1 to 4 years. Adults typically survive several months, sustained by their predatory behavior. Some species exhibit aggregation behavior on flowers to facilitate mating.
ECOLOGICAL IMPORTANCE AND CONSERVATION
Cleridae play a critical ecological role as predators of wood-boring pests and bee parasites, supporting forest health and promoting biological control in orchards without chemical interventions. Rare species such as Aporthopleura sanguinicollis and certain Clerus spp. are listed on regional Red Lists due to loss of old-growth wood and intensive forestry practices. Conservation strategies emphasize the retention of stumps and cavity-bearing trees within ecological networks, as well as monitoring in Natura 2000 sites. Globally, preservation of saproxylic habitats is crucial for maintaining Cleridae diversity, particularly in tropical ecosystems where undiscovered or vulnerable species may be present.