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Walking along the edge of a lake, pond or slow moving stream on a summer day around noon you may see the white tailed dragonfly perched on a stick in the water or skimming back and forth across the water. The male white tailed dragonfly will have a large amber stripe across each wing and a flattened tail that is bluish white in color. The females have large abdomens and may occasionally move to the surface of the water bowing her tail until it touches the surface of the water. The white tailed dragonfly is in the Libellulidae family of insects which means common skimmers. The species is Plathemis lydia and they are in the order Odonata of dragonflies and damselflies. Dragonflies are easily distinguished from other insects by the way they hold their wings out to the sides when resting.
These large insects are easy to observe although on most occasions you may only find the males at first. They are best found in the middle of the day even though the females trips to water are short periods when she will mate and lay eggs before leaving. The male white tailed dragonfly will arrive at the water source, skimming across the surface briefly and then remaining near a small section of the shore area. It is believed this social behavior is used as a means of choosing his territory. Once the male has chosen his area he will repeatedly return to the same spot each day. If no females are present the male white tailed dragonfly will engage in three distinct behaviors. First he will choose areas to perch that give him the best advantage. This may be one particular area or can be up to three and may include reeds, sticks, rocks or even logs on the shore. Once these are chosen he will perch in his area facing the center of the water. Occasionally he will leave the perch slowly flying about the area before returning to his perch.
When another male enters his chosen area this male dragonfly will fly straight at the intruder in an attempt to chase it away. In some cases the two may face each other flying up a few yards in the air and then chasing each other back and forth across the area. Or the male may move below the intruder, quickly flying upward until he makes contact with the intruder with an audible clattering of wings. Both will then fly into the air and off to one side. The male white tailed dragonfly signals his dominance by raising the abdomen to show the white upper surface. To signal sub-ordinance he will lower is abdomen to hide this white surface. This happens so quickly that it almost appears as if the male is flashing the intruder. If an area has few males one may dominate chasing away all intruders. But in areas where several males are found there will always be one that is dominant over all the others. When feeding on the smaller insects that make up the majority of their diet they will dart out grabbing their prey with their long hairy legs. They then return to their perch to eat their prey.
When the intruder is a female the dominant male will approach her, hovering over her while grasping her thorax with his legs and mate. When he releases the female she will immediately begin to lay eggs, dipping the tip of her abdomen in the water to wash them off before flying away. The eggs will hatch after one week and the nymphs will leave the water for the first two weeks to begin eating other smaller insects. After this feeding period they will return to the water where they will go through ten or more molts before becoming adults. In many cases this will take them through the winter months which are spent under the surface of the water.
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