A Recent Expansion of its Queensland Range by Eupristina verticillata, Waterston (Hymenoptera, Agaonidae, Agaoninae), the Pollinator of Ficus microcarpa l.f. (Moraceae)

摘要

In 2004, the first Ficus microcarpa seedlings were observed self-establishing in Brisbane, Queensland. Prior to this the only F. microcarpa in the city were cultivated specimens. This self-establishment is a certain indicator of the presence of Eupristina verticillata, the obligate pollinator wasp of F. microcarpa. A Ficus species must exceed a critical population size (CPS) for its pollinator, a species of agaonid wasp, and other non-pollinator symbionts to colonize a new area and then maintain their new population. This CPS has often been estimated to be approximately 300 mature trees. The CPS for F. microcarpa has been exceeded in Brisbane for some time. Brisbane has been colonized by the wasps Odontofroggatia galili (a gall species), since at least 1975, and E. verticillata, since at least 2004. Previously, the southern extreme of the range of E. verticillata was central Queensland, approximately 600 km north of Brisbane. This was probably achieved through a stationary, inland, trough system drawing tropical air to the southeast over a few days. Brisbane's new E. verticillata population may not persist, as it must compete for short-styled F. microcarpa flowers with a long established O. galili population. Further, it must contend with a winter of greater duration and lower mean temperature than its tropical origins may allow.