Cranefly (Leptotarsus species)
Species: Leptotarsus (Many)
These native craneflies are common in gardens and can be seen hanging on walls inside and outside houses with their wings out spread. There are many crane flies in the Leptotarsus species.
Craneflies seem long and gangly, with very long legs, and a long slender abdomen. The wings are often held out when at rest, making the large halteres easily visible. Unlike most flies, crane flies are weak and poor fliers with a tendency to "wobble" in unpredictable patterns during flight, and they can be caught without much effort.
Adult crane flies feed on nectar or they do not feed at all; once they become adults, most crane fly species live only to mate and die. Their larvae live in rotting plants and in the soil. They do not bite humans.
These flies re interesting because they have halteres which are small knobbed structures found as a pair in some two-winged insects. They are flapped rapidly and function as accelerometers to help the insect maintain stability in flight. Halteres operate as vibrating structure gyroscopes. They flap up and down as the wings do and tend to maintain their plane of vibration. If the body of the insect changes direction in flight or rotates about its axis, a Coriolis force develops on the vibrating haltere, deflecting it from its stroke plane. The animal detects this deflection with sensory organs known as campaniform sensilla located at the base of the halteres. The planes of vibration of the two halteres are orthogonal, each forming an angle of about 45 degrees with the axis of the insect. Halteres thus act as a balancing and guidance system, helping these insects toperform their fast aerobatics. In addition to providing rapid feedback to the muscles steering the wings, they also play an important role in stabilizing the head during flight.
Halteres they can be seen on each side of the wings in a photo below Click photo for enlargement.