Mg. Wright et Mj. Samways, Plant characteristics determine insect borer assemblages on Protea speciesin the Cape Fynbos, and importance for conservation management, BIODIVERS C, 8(8), 1999, pp. 1089-1100
The influence of regional climate, biotope and host-plant variables on the
frequency of occurrence of insect borers associated with infructescences of
Protea species in the species-rich flora of the Cape Fynbos was investigat
ed. Large samples of infructescences (n = 1000) were collected on a seasona
l basis and borers identified and quantified. Data were analysed using DECO
RANA and CANOCO so as to correlate environmental variables with borer occur
rence. Distinct differences in frequency of occurrence of the various insec
t taxa were recorded on the various plant species studied. These difference
s were primarily accounted for by physical host-plant characteristics (infr
uctescence and seed set variables), and secondarily, by biotope variables a
nd climatic factors. Fynbos plant characteristics therefore play a major ro
le in determining insect abundance. Plant diversity in the Fynbos is mainta
ined by burning. These management burns, however, should not be applied too
frequently or over areas large enough to extirpate any borer species. As t
hese borers are excellent umbrellas for many other insects, their conservat
ion covers Fynbos insect diversity in general.