THE LONG HORNED BEETLES OF SOUTH FLORIDA (CERAMBYCIDAE, COLEOPTERA) -BIOGEOGRAPHY AND RELATIONSHIPS WITH THE BAHAMA ISLANDS AND CUBA

South Florida is a floral and faunal transition zone between the Nearc tic region and the West Indian part of the Neotropical region. Ninety- one species of Cerambycidae are known from the south Florida mainland and 53 species of Cerambycidae from the Florida Keys. The cerambycid f auna of south Florida is about equally of Neotropical (53%) and Nearct ic origin (47%). Since the Florida Keys were entirely submerged severa l times in the Pliocene and Pleistocene epochs, the present cerambycid fauna is predominantly the result of late Pleistocene - Holocene over land dispersal from south-central Florida and overwater dispersal from the West Indies (Bahama Islands and Cuba). Species-area and species-d istance relationships for the islands form significant regression line s as predicted by the equilibrium theory of island biogeography. The p resence of a ''distance effect'' is surprising, since it is usually co nsidered that only during the past 10000 years has the southern tip of the Florida peninsula been fragmented into the present-day islands of the Keys by a rising sea level. An alternative geological scenario, s upported by this study, suggests that the present islands of the Keys have appeared as the sea level fell only within the past 6000 years, a nd the fauna is a more recently derived one.