Tandem
Flight and
Oviposition Flight in Libellula composita (Odonata: Anisoptera:
Libellulidae) Photo
above right: Libellula
composita
pair in tandem flightWhile in the BLM Overflow Area adjacent to Bottomless Lakes State Park in Chaves County, New Mexico in July of 2001, I had the opportunity to observe males, females, and tandem pairs of The Bleached Skimmer (Libellula composita) in flight. I used a 200 mm Nikon macro lens and a flash to take a series of pictures of the species in flight. Although many of the images are not exceptionally clear, they are good enough to show some interesting facets of tandem flight and of method of oviposition in this species. Some of the tandem flight pictures are accessible from my Natural Flight web page as well, but I wanted to group them together here so they could be compared more readily. By clicking on any picture, it will be brought up to full screen (760 pixels wide) size.
In
these three photos it is interesting to see how the female uses her legs to grip
the male's abdomen. The abdomen of the male is thus sort of wrapped around
the head of the female. Compare this to the pictures
of Sympetrum corruptum, where the female does not grasp the male
abdomen. This is the formation in which the pair fly about
from place to place between actual bouts of oviposition.
The male and female do not generally seem to be flapping with fore and hind wings of each in phase with those of the other, but the respective wing pairs are not very far out of phase either.
In this pair of photos the male and female are both hovering, with their bodies held nearly vertically, so that the female can lay her eggs. She does so by flicking the tip of her abdomen in the water to wash off the small mass of eggs that has accumulated on the underside of her terminal abdominal segments. In the picture at right above, the water droplets that she has flipped up in the process of ovipositing can be seen near the bottom center of the picture, showing how forcefully she has flicked her abdomen.
Females in this species also oviposit alone at times. The next two photos show a single female ovipositing. One is a front view, the other a side view. In both pictures, the water scooped up off the surface and propelled by the flick of her abdomen can be seen. Note that in the picture to the left, the jet of water is wavy or sinusoidal - this indicates that, as the female's abdomen tip was traversing the water, she was oscillating in a rolling motion. This is a neat indication of the complicated dynamics of dragonfly flight. I have written a paper on this that will appear in Odonatologica in 2004.
At right is a scanned image of the underside of a female
Libellula composita. It shows the shape and appearance of the ventral side
of the terminal abdominal segments, including the vulvar lamina and the flanged
area of the 8th abdominal segment. It is provided to aid in interpreting
the oviposition photos, in two of which this area of the abdomen can be clearly
seen.