Table 2.
Functional morphology of the complex tibial organ in tympanate tree weta (Hemideina) and atympanate ground weta (Hemiandrus).
| Hemideina species Tree weta | Hemiandrus pallitarsis Ground weta | |
|---|---|---|
| Tympana | Large foreleg tympana | no tympanal membranes |
| Acoustic vesicles | Tracheal vesicles in tibia | no tracheal vesicles in tibia |
| SGO sensilla | Many SGO sensilla (~70) | medium number of SGO sensilla (~50) |
| CA sensilla foreleg | High number of CA sensilla (50–53) | rather low number of CAH sensilla (12) |
| Serial CA/CAH gradient | clear gradient in CA sensilla from T1 (high) to T3 (low) | no serial gradient in CAH sensilla |
| Size of CA/CAH somata | become smaller in distal CA | similar over CAH |
| Distal CA/CAH sensilla | double row of distal CA somata | no double row of CAH somata |
| IO anatomy | IO compact | prominent IO extends dorsally in tibia |
| IO mass | IO mass attached dorsally by connective strands | IO/CAH attached jointly at dorsal cuticle over broad area |