Abstract
Thanatosis are death feigning may be induced in Aphodius by applying the mechanical stimulus such as needle to the thorax on the dorsal side or the ventral side. During thanatosis state the insects assume a posture which somewhat resembles to that of coccinellids; the femora, tibia and tarsi of the legs fold on each other and the antennae do not press to the head but take up the normal position. The termination of thanatosis is instantaneous like coccinellids; the antennae do not show any movement but the legs straight way start moving with jerk.
The insect does not show any symptom of pain during thanatosis state.
There appears to be a relation between the intensity of the stimulus and the duration of thanatosis, as the different periods of death feigning are recorded on subjecting the beetles to mechanical stimuli of different grades.
A decline in the duration of thanatosis takes place on subjecting the insects to repeated applications of the same stimulus, probably due to the approach of the fatigue stage.
Like Carausius morosus the beetles, under long exposures of light at fixed level of illumination run into a prolonged state of thanatosis thereby exhibit their sensitivity to the light.
At low temperature since the insects become inactive they show an increase in the duration of death feigning which decreases when the temperature is raised as they get excited.
The insects terminate thanatosis earlier than the normal period on subjecting them to heat radiation while they are in thanatosis state.
The starved beetles as they become inactive show an unusual rise in the duration of death feigning.
