Anisoptera: Ancient and Deadly

By -

Stock-still, the dragonfly waits upon its perch. Its head, filled on both sides by enormous compound eyes, swivels about, seeking unwitting insect prey. Spotting a likely target flying over the water, it powers up its stiff wings and buzzes into the air. With incredible agility and accuracy, the predator intercepts its prey mid-flight and carries it back to its perch, where the unfortunate victim is consumed. After finishing its meal, the adult dragonfly resumes its search. Meanwhile, under the water’s surface, a dragonfly nymph displays hunting prowess to rival the adult. Crawling among vegetation at the pond’s bed, the naiad spots a tadpole. Despite the immature amphibian’s greater size, the nymph approaches it stealthily. When in range, the naiad reveals its secret weapon: an extendable mouthpart ending in sharp, grasping pincers. In a flash, the hunter deploys its apparatus, capturing the tadpole and devouring it.

                                                     Image by Andre Karwath, courtesy of Wikipedia

    Dragonflies (suborder Anisoptera) belong to the order Odonata, which they share with the damselflies (suborder Zygoptera). There are about 3,000 individual species within Anisoptera, all of which inhabit freshwater ecosystems. Dragonflies are relatively large insects. The smallest extant species has an adult wingspan of about 0.8 inches, while the largest has a wingspan up to 6 inches at maturity (https://www.britannica.com/animal/dragonfly). Fossils indicate that the ancestors of modern dragonflies were even larger. During the Paleozoic era (541 million years ago to 252 million years ago), some specimens of the extinct order Protodonata had wingspans as wide as 30 inches, greater than the wingspans of many modern birds (https://ucmp.berkeley.edu/arthropoda/uniramia/odonatoida.html).

                                                                                    Protodonata fossil, courtesy of Wikipedia

    Unlike beetles, true flies, wasps, and other holometabolous insect taxa, Anisoptera are hemimetabolous. Their larvae, also known as nymphs or naiads, resemble the adult in shape and function of certain body parts, though not necessarily in proportion or microhabitat. Hemimetabolous insects undergo incomplete metamorphosis, morphing directly from larva to adult through a series of molts without a pupal stage (https://www.britannica.com/science/metamorphosis#ref187021). Dragonfly nymphs are formidable aquatic predators. The labium, the posterior mouthpart on the ventral side of the nymph’s head, is fused to form a large structure called a “mask.” This apparatus, which can be extended very rapidly, ends with a pair of formidable pincers for capturing and holding prey. Victims may include crustaceans, annelids, tadpoles, and small fish (Britannica, dragonfly, 2020). Dragonfly nymphs are entirely aquatic and rely on gills within their rectum to respirate. Water is rhythmically drawn into the abdomen and expelled through the anus to maintain the flow of oxygen to the respiratory system. When a quick escape is necessary, the nymph can expel a jet of water from the abdomen that is enough to propel it to safety (Britannica, dragonfly, 2020).

    Dragonflies belong to the infraclass Paleoptera, which means “old wing” in Greek. The venation pattern of Anisoptera wings is much different than those of groups within infraclass Neoptera (“new wing”), a group that includes orders Diptera, Coleoptera, Hemiptera, Hymenoptera, Lepidoptera, and several other orders (Daly et al 356). However, despite their primitive wing structure, dragonflies are highly competent flyers. Adults can hover or fly straight up or down and are capable of rapid changes in direction. As a result, dragonflies are accomplished flyers. One species, the globe skimmer dragonfly (Plantala flavescens), makes the longest migration of any insect, flying over 11,000 miles across the Indian Ocean and back (Zielenski). Dragonflies also have massive eyes that fill most of the head region, allowing the insect to see almost anything not directly behind it. While hunting flying insects, Anisopterans employ their bulging eyes to track prey and plan an intercept based on the victim’s flight path. The dragonfly’s ability to fly and their massive eyes make them formidable aerial predators. With success rates as high as 95 percent for some prey species, dragonflies are considered one of the most effective animal predators in the world, far outpacing quintessential vertebrate predators (Combes et. Al, 2013).

  Dragonfly Eyes, courtesy of rcannon992



Works Cited

Britannica, The Editors of Encyclopaedia. "dragonfly". Encyclopedia Britannica, 10 Jun. 2020, https://www.britannica.com/animal/dragonfly. Accessed 19 May 2022.

Britannica, "metamorphosis". Encyclopedia Britannica, 4 Feb. 2020, https://www.britannica.com/science/metamorphosis. Accessed 19 May 2022.

Daly, Howell V., Doyen, John T., Purcell III, Alexander H. Introduction to Insect Biology and Diversity. New York, Oxford University Press, 1998.

Introduction to the Odonata. University of California Museum of Paleontology, https://ucmp.berkeley.edu/arthropoda/uniramia/odonatoida.html. Accessed 19 May 2022.

S. A. Combes, M. K. Salcedo, M. M. Pandit, J. M. Iwasaki. “Capture Success and Efficiency of Dragonflies Pursuing Different Types of Prey.” Integrative and Comparative Biology, Volume 53, Issue 5, November 2013, Pages 787–798, https://doi.org/10.1093/icb/ict072

Zielinski, Sarah. “14 Fun Facts About Dragonflies.” Smithsonian.com, Smithsonian Institution, 5 Oct. 2011, https://www.smithsonianmag.com/science-nature/14-fun-facts-about-dragonflies-96882693/.

 

 

Image Links

Red Dragonfly:

https://en.wikipedia.org/wiki/Dragonfly#/media/File:Mesurupetala,_dragonfly,_Late_Late_Jurassic,_Tithonian_Age,_Solnhofen_Lithographic_Limestone,_Solnhofen,_Bavaria,_Germany_-_Houston_Museum_of_Natural_Science_-_DSC01817.JPG

Fossil Paleoptera:

https://en.wikipedia.org/wiki/Dragonfly#/media/File:Sympetrum_flaveolum_-_side_(aka).jpg

Dragonfly Eyes:

https://rcannon992.com/2019/03/17/dragonfly-eyes/


Comments

Post a Comment

Popular posts from this blog

Mimicry: Being Masters of Disguise

By Anonymous -
Image
By: Cassidy Herbster, Cari Marota and Malik Mason  First to explain mimicry, it is copying another insect or inanimate object to aid in avoidance of predators and/or catching prey. There are two types of mimicry: batesian and mullerian. Batesian refers to when only the insect who is mimicking benefits while mullerian is when both the model and mimicking insect benefits. Most common way is with coloring. The colors of the bad tasting, venomous, or vicious insect is copied by a different insect to avoid being eaten by a predator, though the copy cat doesn't actually have that defense, it just appears so.  They also use coloring to blend in to catch prey or avoid being prey.  The insect being mimicked is called the model. Insects will not always only mimic other insects, but creatures such as arachnids or reptiles. Mimicry might not be for the whole lifetime of the insect. For example, the larvae of an insect could mimic a predator but grow up and not use mimicry as su...
Read more

Bear Lake Bog

By Anonymous -
Image
            A picture of a wetland bog from the Northern Hemisphere Source: https://infograph.venngage.com/p/176597/bog-biome               From lakeside dunes to old-growth white pine forests, Michigan is enriched with unique ecosystems. Although many of which have been claimed by society for agricultural and suburban means, portions of conserved land have been reserved for public recreation and admiration of wilderness. Wetland bogs are microcosms that serve as host to many unique organisms. While they used to be much more prevalent in the United States, they are still an important ecosystem in the US. This blog will expound on our class’s excursion to a bog named Bear Lake Bog.             Bear Lake Bog is located about six miles south of Au Sable campus and is found between the East Lakes and Bear Lake. We visited this bog on May 22, 2018. We broug...
Read more

Honey Bees and Colony Collapse Disorder

By -
Image
            Beginning in the winter of 2006 to 2007, beekeepers began to notice a significant decline in losses of their hives, as high as 30 to 90 percent for no apparent reason ( Kaplan, 2012 ). The population of honeybees continues to decline today. The disappearance of these honey bees is now known as the colony collapse disorder (or CCD). This is concerning because honeybees play an important role in the pollination of plants, especially for agriculture but the loss of honeybees doesn’t stop there. The honey that honeybees make has significant medicinal properties. Honey provides antioxidants, relief to colds, and when applied to scrapes or wounds, it aids the healing process with its natural antibacterial and antimicrobial properties ( Shock, 2015 ). It promotes digestion. The loss of honeybees is not only a threat to biodiversity but the health of plants and people. Colony losses of managed ...
Read more