Orchids are masters of sexual deception, with petal ornaments that so closely resemble female insects that their flowers attract amorous, pollinating males. Allan Ellis at Stellenbosch University in Matieland, and Steven Johnson at the University of KwaZulu-Natal in Pietermaritzburg, both in South Africa, now report that the daisy Gorteria diffusa uses a similar ruse.

The duo observed the behaviour of bombyliid flies around several forms of the daisy (pictured) in both the field and the laboratory. Male flies were attracted to some of the flowers (top row) and were mildly curious about others (bottom row), but showed little interest in daisies with minimal fly-like ornamentation.

The researchers also found that the males attempting to mate with the petal ornaments spread pollen between flowers more effectively than did the more sedate females, which came just to feed.

Credit: A. G. ELLIS

Am. Nat. doi:10.1086/656487 (2010)