BP 13 Kristy Smith

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Odonata Gomphidae (BP13)

Odonata Gomphidae is the name given to the Order and Family of an aquatic insect [1]. There are approximately 900 species of this type of insect [1]. The common name is the clubtail dragonfly [1]. This name was given to the insect due to the enlargement of the posterior portion of the abdomen which resembles a club [2]. They are found in flowing freshwaters located down into the silt or sediment [2]. They are considered burrowing predators as they wait for their prey [3].

Location of collection: Beaver Pond

Date of collection: August 2012

Shannon-Wiener Index of Biodiversity:


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Distinguishing morphological features of Order

  • Cerci distinctly shorter, at most 0.8x the length of the epiproct and paraprocts [2].

Scientific Name

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Odonata
Family: Gomphidae
Genus: Unknown
Species: Unknown

Geographical Distribution

Odonata are found worldwide, except in the polar regions. They are located in and near freshwater habitats [4].


Life cycle


These insects have two stages in their lifecycle; larvae, or nymph, and adult [4]. Nymphs are aquatic and are found in freshwater under rocks, attached to plants, and almost anywhere else within the freshwater environment [4]. Some species of odonata are tolerant of high salt and some are considered semi-terrestrial, as they can tolerate areas that are low in water [4]. Nymphs are indiscriminate hunters and eat anything smaller than them, including other nymphs [4]. They undergo 10-20 molts before they reach adulthood and their metamorphosis does not have a pupal stage [4]. During metamorphosis, the nymph is cocooned a good distance from water, as there is a need for the cocoon to stay attached to a fixed support [4].


When the adult emerges from the cocoon, it keeps its distance from water while it feeds and becomes fully mature, which normally takes a few days [2]. Fully matured adults have wings with a glassy sheen and have developed color on their bodies [2]. Adults are strong fliers and have great eyesight [2]. At this stage, most females do not stay around water accept to find males and to lay their eggs [2].

Sexual dimorphism

Sexual dimorphism does occur within many different species. Scientists have studied and found that although both males and females are similar in size in the nymph stage, in some species, females become larger than males upon reaching maturity [5]. The female's larger mass is found in the thoracic and abdominal regions, which could be indicative that they are larger due to the ability to carry eggs [5].



Larval/nymphal stage: these insects are ambush predators that are non-discriminatory [1]. They feed by capturing small prey with their lower lips [1]. At this stage, they feed intensively and they will eat a variety of things such as:

  • Insects
  • Worms
  • Small fish
  • Tadpoles

Adult stage: at this stage, the insect will hunt, many times in groups, and eat whatever is available [3]. They feed by scooping up small prey with their spiny legs [1]. Females take in more food than males, especially when developing eggs [3]. Their diet consits of:

  • Flies
  • Termites
  • Mosquitos
  • Flying ants
  • Mayflies
  • Gnats


These insects are typically found near or in running or standing freshwater [2]. They are found near or in rivers, lakes, streams, seepages, bogs, swamps, and temporary pools [2]. They typically are a sign of a good quality ecosystem [2]. The most abundant of these insects are found in tropical areas where there are a variety of microhabitats [2].

Larval/nymphal stage: Larvae are found under rocks or clinging to plants [1].

Adult stage: Adults are found flying and actively hunting for food and places to lay their eggs [1]. They do not spend as much of their time in or near water as they did in their nymph stage.

Ecological Importance

Odonata are insects that make up the lower part of the food chain and therefore, are a good determinant of ecosystem quality [6]. When the population counts of these insects are up, it is a sign that the environment of the habitat is ideal. In the event that the population counts of these insects decrease, it could be indicative of problematic water quality or issues relating to the prey that these insects feed on. This allows scientists to determine ecosystem quality before it reaches the higher level predators [6].

Economic/agricultural/human health importance

Odonata populations, as mentioned above, are a population of insects that are both predator and prey and are found in and near aquatic ecosystems. The rise and fall in their populations are indicative of the quality of the ecosystems in which they are known to reside. This has an impact on human health by the scientific ability to count and determine the quality of habitats at an early stage, thereby protecting higher level predator populations from becoming endangered or extinct. The detection of low quality ecosystems, and more importantly water quality, can have an impact on the health of human populations. The ability for these insects to offer human protection against pests such as mosquitos, is also important for the health of humans. Economically and agriculturally, the larvae of these insects have been used to control pest insects, while the adult insect has been used for bait by fisherman and as a minor food item in some countries around the world [2].

PCR product

Kristy PCR 2.jpg

  • Lane 1: empty
  • Lane 2: BP12
  • Lane 3: empty
  • Lane 4: 1kb ladder
  • Lane 5: empty
  • Lane 6: BP13
  • Lane 7: positive control
  • Lane 8: empty
  • Lane 9: negative control
  • Lane 10: empty

Sequence data

Due to either error in dilution or problems arising from the sample quality, I was unable to retrieve DNA sequence data for this sample. Since I could not obtain this information, I could not determine the genus or species of this specimen via the National Center for Biotechnology Information (NCBI).


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