Overview
These fungus-feeding species, which live in leaf- litter and on dead twigs, are regarded as the most primitive of extant Thysanoptera. There are about 15 species worldwide in 3 genera, 2 of which are monobasic.
Merothrips
(3 Australian spp.) is predominantly Neotropical but with several species apparently distributed through the tropics and subtropics by trade.
Description
The antennae of Merothripidae species are eight or nine segmented, with the distal segments fully distinct from each other, and the sensoria on segments III and IV transverse or lenticular to slightly inflated. Sternite VII of females bears a pair of lobes each with two setae on the posterior margin, but these lobes are not easy to see unless slide-mounted specimens have been well cleared. This character state is shared with Melanthripidae species.
The head and thorax differ in structure considerably between species of Merothripidae. Most
Merothrips
species are minute and wingless, with the head unusually small and the tentorial bridge not developed, and the dorsal surface of the head of males is occupied by a large glandular area. In contrast, the larger species in the family are winged with a larger head in which the tentorial bridge is well-developed, and the males are not known.
Distribution
Erotidothrips
has been taken widely but rarely in the Old World tropics, including northern Australia, but
Damerothrips
is known only from Brazil. Most of the species of
Merothrips
are from the Americas, particularly the Neotropics, but
M. floridensis
is particularly widespread around the world, including southern Europe and Australia (Mound & O'Neill, 1974).