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Dragonflies - living fossils

Natural History

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GEOGRAPHIC RANGE AND HABITAT

    Tachopteryx thoreyi lives in the Eastern United States, from as far North as New

York State, to as far South as Northern Florida. They range as far West as Eastern

Texas and Oklahoma.  See map below. The grey petaltail inhabits deciduous forests.

They require clean spring fed seeps in these forests.

(Dunkle, 2000, p.250)
tachorange.jpg

BEHAVIOR

    For those who live where winters become cold, larvae must winter under leaves, in the mud of seepages or shallow water, until spring. Adults do not migrate, nor do they survive the cold weather. (Novak, 2002) and (Dunkle, 2002). According to Ethan Bright and Mark F. O'Brien, at the University of Michigan, larvae may grow for 3 years prior to emerging as and adult. Adults like to perch on sunny areas of tree trunks, where they are quite camouflaged. (Dunkle, 1981, p.194), (Bright & O'Brien, 1999) Sometimes when the temperatures drop, they “wing-whir” to increase their temperature. They can hover, or fly at about 100 body lengths per second, as well as backwards at about three body lengths per second. (Waggoner &  Sabet-Peyman , 2000, introduction to the odonata)

tachodrawing.jpg

 

Reproduction

    Male t.thoreyi k seek females 23 days after emergence. (Dunkle, 1981, p. 195) Males search for females by flying up the sunny side of tree trunks, and then fly smoothly to search the next tree trunk. At other times, males wait for females near the seeps, usually from around 10 am to 4 pm. They wait in sunny places on thick weeds and vines. (Dunkle, p.194) It was noted by Dunkle, t. thoreyi also hunted prey while seeking a mate, which was not characteristic of other anisoptera. Mating occurs high in the forest canopy while in flight. The male grasps the female by the head, and they fly in tandem. The female curves and they form a “wheel position”. (Trueman  & Rowe, 2001) In some species, the male removes any other males’ sperm with a scoop-like appendage prior to depositing his own. In some species, the pair remain in tandem while the female lays her eggs, in others, the male hovers nearby to guard her from other males, while some species fly away and the female lays eggs alone. (Trueman  & Rowe) It is not discussed which behavior t. thoreyi exhibit. T. thoreyi females lay eggs among roots in thick grasses and fallen leaves, or mud. Their ovipositors contain blades to assist with this. T. thoreyi females lay long oval shaped eggs, which start out yellow, then turn orange-brown. (Dunkle, p.190) The incubation period is 32 days (for eggs hatched in captivity at room temperature). (Dunkle, p.190) The larvae come out of the egg through a curved slit. They are pale brown at first, and eventually turn dark brown, with a white stripe on the abdomen. While in the larval stage, they molt many times the larvae eat other insects, such as small cockroaches. They prefer mud to water, and do not swim. Dunkle supposes this helps prevent them from being washed away when it rains. There is no pupal stage, so they are called hemimetabolous, meaning partial metamorphosis. When the adult is ready to emerge, they cling to upright stems, and the wings open from the base to the tip. The wings have a pinkish tint when newly emerged. Dunkle states he did not find t. thoreyi to be shy, as another naturalist had thought, and in fact, these dragonflies even landed on people at times.

tachofeeding.jpg

DIET

    T. thoreyi are carnivorous. They can capture larger sized prey than most anisoptera. (Dunkle, 1981, p.195) Some examples of what they were eating are: butterflies, including Swallowtails, moths, other odonates, and beetles. They will pretty much eat whatever kind of insect is available. Some have even been know to eat tadpoles and tiny fish. They are valuable for keeping numbers of mosquitoes down.

Close Encounters    I chose this dragonfly because I encountered it a few years ago in Stoney Brook State Park while camping. I was fascinated by it’s prehistoric appearance. In fact, the first time I had one zoom by me, I was startled by its size, and yelled “What the heck was that?!” It was like something out of “Jurassic Park”. A day or two later, on the same camping trip, I noticed one had landed on one of the trunks of a nearby tree. The sun glistening on its huge wings gave it away, otherwise it would have been perfectly camouflaged. I walked slowly towards it, with my arm outstretched. I was ably to pluck it off the tree, holding it by the thorax. I called my kids over to see it. They were delighted! I wasn’t able to hold on to it very long, however. I was surprised by it’s strength. The dragonfly, reached behind itself, and pried itself free. Unperturbed, it slowly glided off into the forest. The size of this individual was larger than listed in any articles I read. It was easily close to four inches long, and its thorax was as big around as my fifth finger. (About 10 mm in diameter)    

tachodunklebook.jpg

Interesting e-mail from Paul Novak (NYS DEC- Zoologist NY Natural Heritage Program):

     “How ironic that you saw them there. As part of a project to do Biodiversity Inventories at NYS Parks I had a biologist go to Stony Brook to look for them this year and indeed he found them. This is one of the new locations I referred to. They are indeed, my favorite dragonfly.” pgnovak@gw.dec.state.ny.us

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