Epipompilus is a genus of spider wasps in the subfamily Pepsinae, part of the widespread family Pompilidae. Representatives of Epipompilus can be found in Australasia and North and South America. This distribution may indicate that Epipompilus evolved in Gondwana and is similar to other Gondwanan taxa such as the southern beech Nothofagus and Auracaria.
Epipompilus is found in North and South America, ranging from Argentina to extreme southern United States, with around a dozen known species. One species, E. insularis is endemic to New Zealand. In Australia, the genus reaches its greatest diversity, with a greater number of species and a more varied spectrum of morphological features than among the American species. The Epipompilus species in New Guinea are notably brilliantly coloured and apparently highly evolved species. The genus is restricted to these areas but several Tertiary fossils from the northern hemisphere should probably be placed in Epipompilus.
Ecology and behaviour These wasps are scarce in collections, probably due to their small size and the fact that they rarely visit flowers. A single male E. turneri which was collected on Leptospermum in New South Wales is one of the few flower records. In Australia observation and collection have often been associated with the trunks of living Eucalyptus trees. The morphology of many of the species suggests that they are adapted for crawling under bark and for entering crevices to search for spiders. Prey recorded includes spiders from the family Sparassidae. These wasps probably do not build nests but hunt spiders underneath bark and lay eggs on them as they find them. Taken into consideration with the many primitive structural features of members of this genus, it is suggestive that the hunting technique of Epipompilus represents an ancestral type of behaviour for spider wasps.
One of three new species identified in 2020, based on a single specimen seen in 2018, E. namadji, is named after the Namadgi National Park in the Australian Capital Territory, in which it was found. Efforts are ongoing by teams from the Australian National Insect Collection at the CSIRO to find more of the wasps, after nearly 80 per cent of the national park was lost in the 2019–20 Australian bushfire season.
Species The following species have been assigned to Epipompilus:
Epipompilus albofasciatus Evans, 1972 Epipompilus aztecus Cresson, 1869 Epipompilus caeruleus Evans, 1972 Epipompilus cardaleae Evans, 1972 Epipompilus compactus Evans, 1972 Epipompilus delicatus Turner, 1910 Epipompilus depressus Evans, 1962 Epipompilus excelsus Bradley, 1944 Epipompilus exleyae Evans, 1972 Epipompilus formosus Evans, 1972 Epipompilus gilesi Turner, 1910 Epipompilus hackeri Evans, 1972 Epipompilus inca Evans, 1968 Epipompilus incompletus Evans, 1972 Epipompilus insularis Kohl, 1884 Epipompilus jocosus Evans, 1968 Epipompilus matthewsi Evans, 1972 Epipompilus mirabundus Yuan & Rodriguez, 2020 Epipompilus montivagus Evans, 1972 Epipompilus multifasciatus Evans, 1972 Epipompilus namadji Yuan & Rodriguez, 2020 Epipompilus neboissi Evans, 1972 Epipompilus nigribasis Banks, 1925 Epipompilus pallidus Evans, 1962 Epipompilus papuensis Evans, 1972 Epipompilus pauper Evans, 1972 Epipompilus pictipennis Evans, 1962 Epipompilus pulcherrimus Evans, 1955 Epipompilus rieki Evans, 1972 Epipompilus submetallicus Evans, 1972 Epipompilus taree Yuan & Rodriguez, 2020 Epipompilus tasmanicus Evans, 1972 Epipompilus tucumanus Evans, 1968 Epipompilus turneri Evans, 1962 Epipompilus variegatus Evans, 1972
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