Scymnus creperus
Mulsant, 1850
dusky lady beetle
Scymnus creperus is a small dusky lady beetle (Coccinellidae: Scymnini) native to North America. measure 1.76–2.68 mm and display distinctive coloration: yellowish-red and pronotum with a small black spot, and black with red apices. The is notable for its larval defense mechanism—secretion of a sticky white wax from pores that reduces aggression by the imported fire Solenopsis invicta. It preys on aphids and has been documented feeding on the bird cherry-oat aphid Rhopalosiphum padi.
Pronunciation
How to pronounce Scymnus creperus: /ˈsɪmnəs ˈkrɛpərəs/
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Identification
are distinguished from other Scymnus by the combination of small size (under 3 mm), yellowish-red pronotum with a single small black spot, and black with red markings. The minute size separates it from larger coccinellids like Coleomegilla maculata. Larvae are readily identified by their white waxy covering, which contrasts with the non-wax-secreting larvae of many sympatric coccinellids.
Appearance
are minute, measuring 1.76–2.68 mm in length. The is yellowish-red. The pronotum is yellowish-red with a small black spot. The are black with red apices. Larvae produce a conspicuous white waxy covering secreted from pores in the .
Habitat
Associated with agricultural fields and crop plants where aphids occur. Found in southern regions of the United States.
Distribution
Native to North America. Recorded from Pennsylvania west to Colorado, south to Texas and Florida. Also present in Bermuda.
Diet
of aphids; has been observed feeding on the bird cherry-oat aphid Rhopalosiphum padi.
Life Cycle
Larvae pass through at least three instars; third instar larvae are well-documented. Laboratory rearing on barley seedlings with aphids has been achieved for at least one .
Behavior
Larvae secrete sticky white wax from pores, forming a protective covering. This wax reduces aggression by Solenopsis invicta , enabling larvae to prey on aphids even in the presence of aggressive ants that attack non-wax-secreting coccinellids. Wax removal does not fully eliminate this protective effect, suggesting chemical compounds on the integument may also contribute to defense.
Ecological Role
with potential as a agent in agricultural systems where Solenopsis invicta and other aggressive ants interfere with other coccinellid .
Human Relevance
Investigated for potential in -problematic agricultural environments due to its ability to function where other lady beetles are suppressed by aggressive ants.
Similar Taxa
- Coleomegilla maculataLarger, non-wax-secreting coccinellid with greater susceptibility to Solenopsis invicta aggression; lacks the waxy larval covering and chemical defenses of S. creperus.
More Details
Ant defense mechanism
The wax secretion of S. creperus larvae represents a documented case of chemical defense against a major . The wax and associated integumentary compounds function as defensive , reducing fire ant aggression and mortality.