Meconema thalassinum

The remarkable nocturanl 'song' of this insect is not produced by stridulation but by a rapid drumming of one of the hind legs on teh substrate. It is clearly intended for conduction through the substrate and so the airborne sound produced is incidental and very quiet. To produce the sound the male raises both pairs of wings more or less perpendicularly to the body and vibrates one of the hind legs so the that its tarsus is drummed on the surface of the leaf, twig or any other substrate that the male happens to be using. The drumming is in short bursts of up to a second or slightly longerand these are almost always in sequences of up to seven bursts, separated from other such sequences by intervals of at least several seconds (3-15 s in the songs studied). Each sequence is usally composed of a combination of shorter and longer bursts, with the shorter ones preceeding the longer ones. Each shorter burst usually consists of 3-8 impacts and lasts for about 0.07-0.20s, while each longer one usually consists of 30-50 impacts and lasts for about 0.7-1.3s. The impact repetiton rate, in both shorter and longer bursts, is usually 3-40/s at temperatures up to 25°C, but can be as much as 60/s or more at higher temperatures. The number of short and long bursts in a sequence is very variable: 2-3 short ones followed by 1 or 2 long ones is a common patterm, but there can be as many as 5 of either kind (though not in the same sequence) and some sequences lack short bursts completeky. The interval between successive bursts lasts about 0.2-2.0s.

The quality of the airborne sound depends on the substrate. Drumming on a twig is extremely faint, but if a suitable leaf is used the sound can sometimes be heard from a distance of several metres. [1]

References