diversity and distribution of psocid populations on Mangifera indica L. in Jamaica and their relationship to altitude and micro-epiphyte diversity

(1) Monthly sampling over a 19-month period from mango trees (Mangifera indica L.) from 500 to 4000 ft (152 to 1220 m) on the southern slopes of the Blue Mountains in Jamaica yielded fifty-three species of Psocoptera. (2) The number of species increases with altitude at a mean rate of 3.3 species/1000 ft (305 m) as does their evenness of representation in terms of numbers of individuals. (3) Both the variety and quantity of micro-epiphytes (algae, lichens and fungi) on mango leaf and bark surfaces increase with increasing altitude. (4) The diversity of the psocids and the diversity of the microepiphytes on which they feed, as measured by Simpson's diversity index, are significantly correlated. (5) The psocid species may be grouped into those restricted to the lower altitudes, of which many are not endemic; a larger number restricted to the higher altitudes, almost all of which are endemic; and a few species occurring over the entire altitude range. (6) The extent to which these altitudinal distribution patterns result from man's influence on the vegetation is discussed.