Cycloneda polita

Easily distinguished from other North American lady beetles by the complete absence of spots on the red elytra. The black pronotum with white marginal rim and crescent markings separates it from other spotless species like Cycloneda sanguinea (which has different pronotal markings). Differs from Hippodamia convergens and other common spotted lady beetles by lacking elytral spots entirely. The combination of unspotted red elytra and marked black pronotum is diagnostic for the species.

Adults are small, oval beetles measuring approximately 4-5 mm in length. The elytra are uniformly red to orange-red without any spots or markings, giving the species its "polished" and "spotless" common names. The pronotum is black with distinctive white marginal markings that form a rim and paired crescent-shaped spots anteriorly. The ventral surface is predominantly black. The overall appearance is glossy and highly polished.

Occurs in diverse open habitats including grasslands, prairies, meadows, agricultural fields, gardens, and forest edges. Often found in areas with abundant flowering plants that support aphid populations. The species shows adaptability to both natural and anthropogenic environments.

Western North America, ranging from western Canada (British Columbia, Alberta, Saskatchewan) through the western United States. The species is broadly distributed across the Great Plains, Rocky Mountains, and Pacific Northwest regions.

Adults are active from spring through fall, with peak activity during summer months. The species likely undergoes winter diapause as adults, though specific seasonal patterns vary by latitude and elevation.

Aphids and other small soft-bodied insects such as scale insects and adelgids. The species is a generalist predator of Sternorrhyncha.

Complete metamorphosis with egg, larval, pupal, and adult stages. Eggs are laid in proximity to aphid colonies. Larvae are elongate, dark-colored with orange or yellow markings, and actively prey on aphids. Pupation occurs on vegetation. Multiple generations per year are likely in warmer portions of the range.

Adults are diurnal and actively forage for prey on vegetation. Both adults and larvae are voracious predators of aphids. Adults may disperse by flight to locate new prey patches. Aggregative behavior has been observed at abundant food sources.

Important biological control agent of aphid populations in natural and agricultural ecosystems. As a generalist predator, it contributes to suppression of pest outbreaks and serves as food for larger predators including birds and other insects.

Beneficial insect in gardens and agricultural systems due to aphid predation. Frequently encountered by citizen scientists and naturalists. No known negative impacts; not considered a household pest.

• Cycloneda sanguineaAlso spotless with red elytra, but has different pronotal markings (lacks the distinct white crescents of C. polita) and occurs in eastern North America with limited western overlap
• Hippodamia convergensCommon spotted lady beetle with convergent spot pattern; easily distinguished by presence of spots on elytra
• Coccinella septempunctataSeven-spotted lady beetle with distinct spot pattern; introduced species with overlapping range but readily distinguished by elytral markings

• lady beetle
• ladybug
• biological control
• aphid predator
• western North America
• spotless
• Coccinellidae
• Cycloneda

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
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