PSYCHE 
Vol. 94 1987 No. 3-4 
A MORDELLID-MELOID MIMICRY 
By M. Deyrup 1 and T. Eisner 2 
The Mordellidae are small wedge-shaped beetles commonly 
found in one of the most dangerous of all insect habitats, the open 
inflorescences of plants. Their chief protection against the many 
predators that frequent flowers is a series of convulsive leaps fol- 
lowed by rapid flight, as acknowledged in their common name, the 
“tumbling flower beetles” (Crowson, 1981). Their escape from a 
predator’s grasp is facilitated by their wedge shape and covering of 
smooth, backward-pointing hairs, while their movement and pur- 
chase among stamens and floral hairs may be assisted by rows of 
tibial and tarsal setae strongly reminiscent of the combs of fleas. 
These escape mechanisms, while undoubtedly effective against 
many predators (including entomologists), have the disadvantage 
that they involve abandonment of the feeding site. 
At our study area in southern Florida (Archbold Biological Sta- 
tion, Highlands Co.) one species of mordellid appears to belong to a 
mimetic complex, a strategy by which the beetles might forestall 
attack. The mordellid, Mordellistena comat a LeConte, is a relatively 
uncommon insect that is found during late summer on flowers of 
yellow Asteraceae, especially Heterotheca subaxillaris (Lamarck) 
Britton and Rusby, and Balduinia angustifolia (Pursh) Robinson. 
The reddish pronotum and black elytra of this beetle (Fig. 1, 
bottom) confer a strong resemblance to several species of ne- 
mognathine meloids, especially Gnathium francilloni Kirby (Fig. 1, 
'Archbold Biological Station, P.O. Box 2057, Lake Placid, Florida 33852. 
2 Section of Neurobiology and Behavior, Cornell University, Ithaca, New York 
14853. 
* Manuscript received by the editor July 6, 1987. 
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