Odonata 101: An Introduction to Dragonflies and Damselflies
Dragonflies and damselflies are familiar insects around rivers, streams, lakes, ponds, swamps, and other wetlands. Behind their striking colours and remarkable flight abilities lies one of the oldest surviving radiations of winged insects.
ODONATATAXONOMY
Akbar Alfarisyi
8/2/20267 min read
Dragonflies and damselflies are familiar insects around rivers, streams, lakes, ponds, swamps, and other wetlands. Behind their striking colours and remarkable flight abilities lies one of the oldest surviving radiations of winged insects. Together, dragonflies and damselflies constitute the insect order Odonata, a group widely studied in taxonomy, systematics, ecology, evolution, biogeography, behaviour, and freshwater conservation (Córdoba-Aguilar et al., 2023).
What is Odonata?
The name Odonata is derived from Greek terminology associated with “toothed” structures, referring to the strongly developed mandibles characteristic of these predatory insects. Both larval and adult odonates are predators, although they occupy very different environments during these two stages of their life cycle (Kalkman et al., 2008).
Odonata belong to Palaeoptera, one of the earliest-diverging lineages of winged insects. Their evolutionary history extends deep into the Palaeozoic. However, ancient giant “dragonfly-like” insects should not be interpreted as modern dragonflies. Fossil lineages related to Odonata extend into the Permian, whereas transcriptome-based phylogenetic reconstruction indicates that the major lineages leading to extant dragonflies and damselflies began diversifying during the Triassic (Suvorov et al., 2021).
Odonata currently comprise more than 6,000 recognized species. Pinto et al. (2023), based on the contemporary world checklist available at the time, reported 6,364 species, while earlier estimates suggested that actual global diversity might eventually approach 7,000 species. Taxonomic discovery remains particularly active in tropical regions (Pinto et al., 2023).
This updates the older figure of 5,680 described species reported by Kalkman et al. (2008), which should therefore not be presented as the current global species count.
Dragonfly or Damselfly?
The two major groups encountered today are Zygoptera, commonly known as damselflies, and Anisoptera, commonly known as dragonflies.
Zygoptera – Damselflies: generally slender-bodied, with forewings and hindwings relatively similar in shape. Their compound eyes are usually widely separated. Many species rest with their wings closed or partly spread above the abdomen.
Anisoptera – Dragonflies: generally more robust, with hindwings broader at the base than the forewings. Their compound eyes are typically much larger and often meet or approach one another dorsally. Most rest with their wings extended.
Modern Odonata systematics integrates morphological and molecular evidence to reconstruct relationships among these major lineages. Although the monophyly of the principal extant groups is well supported, relationships among some deeper odonate lineages—particularly within Zygoptera—have historically been difficult to resolve (Kohli & Ware, 2023; Suvorov et al., 2021).
A third, species-poor lineage is represented by the genus Epiophlebia. It has traditionally been associated with the name “Anisozygoptera” because it exhibits a combination of characteristics historically compared with Zygoptera and Anisoptera. Its systematic interpretation has changed substantially as phylogenetic evidence has accumulated. Therefore, the familiar statement that Odonata simply consist of “three equivalent suborders” is an oversimplification of their evolutionary relationships (Kohli & Ware, 2023).
Two Worlds, One Life Cycle
One defining ecological feature of Odonata is their dependence on both aquatic and terrestrial environments. Their life cycle can be summarized as:
Egg → Aquatic larva → Emergence → Adult
Almost all odonate species depend on freshwater habitats during larval development. Both larvae and adults are predators, but the transition from aquatic larva to flying adult produces a major ecological shift during the life cycle (Kalkman et al., 2008). (Springer Link)
Females lay eggs in or near suitable aquatic environments. Depending on the species, eggs may be inserted into plant tissue or deposited directly onto water or wet substrates. After hatching, development proceeds through an aquatic larval stage. Odonate larvae possess a highly modified, extensible prehensile labium, which functions in capturing aquatic prey. The morphology and behaviour of larvae vary substantially according to lineage and habitat. At the end of larval development, the mature larva leaves the water and attaches to emergent vegetation, rocks, roots, tree trunks, or other suitable substrates. The adult then emerges from the larval exoskeleton. The empty larval cuticle remaining after emergence is called an Exuvia. This life cycle explains why Odonata cannot be understood exclusively as terrestrial insects. Their persistence depends on ecological conditions operating across the aquatic–terrestrial interface.
Built to Hunt
Predation is fundamental to Odonata biology. Adult dragonflies and damselflies possess large compound eyes, powerful flight musculature, four independently functioning wings, strong mandibles, and spiny legs adapted to capturing flying prey.
Their visual and flight systems allow sophisticated aerial hunting. Rather than merely following prey, dragonflies can use visually guided interception strategies to approach moving targets. This combination of visual processing and flight control makes Odonata important model organisms for studies of insect neurobiology, sensory ecology, and locomotion. The legs are directed forward during aerial hunting and can form a basket-like structure used to capture prey before transferring it to the mouth. These adaptations make adult Odonata highly specialized aerial predators.
Odonata and Freshwater Habitats
Although adults may disperse considerable distances from water, Odonata distributions remain fundamentally linked to habitats suitable for reproduction and larval development. Odonates inhabit a remarkably broad range of freshwater environments, including:
Rivers and streams
Forest creeks
Lakes and ponds
Marshes and swamps
Peat-swamp forests
Temporary pools
Seepages
Waterfalls
Mountain bogs
Blackwater systems
Artificial water bodies
This ecological diversity means that Odonata should not be treated as a single ecological unit. Some species are ecological generalists capable of occupying disturbed or artificial water bodies. Others are habitat specialists restricted to particular combinations of hydrology, vegetation, water chemistry, forest structure, and microclimate. Kalkman et al. (2008) showed that many odonate species have small geographic ranges and specialized habitat requirements, including species associated with tropical forest seepages, waterfalls, and alpine bogs. Global species richness is particularly high in tropical rainforest running waters, with the Oriental and Neotropical regions among the richest biogeographic regions.
This makes tropical Asia particularly important for understanding global Odonata diversity.
Why Scientists Study Odonata
Odonata have become important model organisms across multiple areas of biological research. Modern odonatology extends beyond conventional taxonomy and includes studies of phylogenetics, sexual selection, reproductive behaviour, physiology, community ecology, macroecology, biogeography, climate responses, and conservation.
Taxonomically, Odonata are particularly informative because adult morphology provides numerous diagnostic characters. Wing venation, male caudal appendages, secondary genitalia, female reproductive structures, body patterning, and other morphological features have historically played major roles in species identification (Pinto et al., 2023).
Modern species delimitation increasingly integrates these morphological observations with molecular, ecological, behavioural, and biogeographical evidence rather than relying on a single character. Pinto et al. (2023) specifically emphasize that differences between specimens alone are insufficient evidence for recognizing separate species. Instead, species hypotheses should ideally be evaluated through comparative and integrative approaches.
Are Dragonflies Bioindicators?
Odonata are frequently described as bioindicators, but that term requires careful interpretation. The presence of many dragonflies does not automatically indicate a healthy freshwater ecosystem. Disturbed habitats may contain large populations of widespread generalists while specialized species associated with intact habitats disappear.
Consequently, community composition is usually more ecologically informative than abundance alone. Odonata have been used successfully in environmental assessment and conservation because many species possess specific habitat requirements, while their relatively conspicuous adults facilitate field surveys. Kalkman et al. (2008) explicitly identified Odonata as useful organisms for assessing environmental health and informing conservation management.
Useful ecological information may therefore include:
Species richness and identity
Relative abundance
Presence or absence of habitat specialists
Assemblage composition
Functional traits
Larval assemblages
Species turnover among habitats
Responses to environmental gradients
These biological data become substantially more informative when evaluated together with environmental variables such as water chemistry, temperature, dissolved oxygen, conductivity, vegetation structure, canopy cover, hydrology, and land-use disturbance.
Therefore, Odonata should not simply be described as “clean-water insects.” Different species respond differently to environmental conditions, and it is the structure and turnover of the assemblage that often provide the strongest ecological signal.
Odonata in a Changing World
Odonata are strongly influenced by changes occurring in both freshwater habitats and their surrounding terrestrial landscapes. Habitat loss, forest conversion, wetland drainage, pollution, hydrological modification, agricultural expansion, urbanization, and climate change can modify the environmental conditions required by odonate species. Species with restricted distributions or narrow habitat requirements may be particularly vulnerable.
Biogeographical studies increasingly examine how climate, geographic barriers, evolutionary history, species traits, and landscape change interact to determine Odonata distributions (Beatty, Alves-Martins, Smith & Verheyen, 2023).
Conservation of Odonata therefore requires more than protecting adult dragonflies.
It requires maintaining the ecological processes that support their entire life cycle—including freshwater habitats, natural hydrology, riparian vegetation, appropriate water chemistry, aquatic vegetation, forest structure, and connectivity across freshwater landscapes.
More Than Dragonflies
Odonata provide an unusually accessible entrance into freshwater biology. A damselfly perched beside a peat-swamp stream or a dragonfly patrolling a forest river represents only the visible adult stage of a biological system extending beneath the water and across the surrounding landscape.
Its occurrence may be influenced by hydrology, water chemistry, aquatic prey, vegetation structure, microclimate, dispersal, evolutionary history, and interactions with other organisms.
Learning to identify dragonflies and damselflies is therefore only the beginning. The more important ecological question is:
"Why does a particular species occur here but disappear somewhere else?"
That question transforms dragonfly observation into odonatology—and connects taxonomy with ecology, evolution, biogeography, and conservation.
References
Beatty, C. D., Alves-Martins, F., Smith, B. D., & Verheyen, J. (2023). Biogeographical ecology in Odonata. In A. Córdoba-Aguilar, C. D. Beatty & J. T. Bried (Eds.), Dragonflies and Damselflies: Model Organisms for Ecological and Evolutionary Research (2nd ed., pp. 167–186). Oxford University Press. DOI: 10.1093/oso/9780192898623.003.0013. (OUP Academic)
Córdoba-Aguilar, A., Beatty, C. D., & Bried, J. T. (Eds.). (2023). Dragonflies and Damselflies: Model Organisms for Ecological and Evolutionary Research (2nd ed.). Oxford University Press.
Kalkman, V. J., Clausnitzer, V., Dijkstra, K.-D. B., Orr, A. G., Paulson, D. R., & van Tol, J. (2008). Global diversity of dragonflies (Odonata) in freshwater. Hydrobiologia, 595, 351–363. DOI: 10.1007/s10750-007-9029-x. This is the appropriate journal citation rather than citing the Springer book-chapter DOI used in some databases. (Springer Link)
Kohli, M. K., & Ware, J. L. (2023). Odonata systematics. In A. Córdoba-Aguilar, C. D. Beatty & J. T. Bried (Eds.), Dragonflies and Damselflies: Model Organisms for Ecological and Evolutionary Research (2nd ed., pp. 295–308). Oxford University Press. DOI: 10.1093/oso/9780192898623.003.0021. (OUP Academic)
Pinto, Â. P., Bota-Sierra, C. A., & Marinov, M. (2023). Species identification and description. In A. Córdoba-Aguilar, C. D. Beatty & J. T. Bried (Eds.), Dragonflies and Damselflies: Model Organisms for Ecological and Evolutionary Research (2nd ed., pp. 263–278). Oxford University Press. DOI: 10.1093/oso/9780192898623.003.0019. This citation is also directly supported by your uploaded source chapter. (OUP Academic)
Suvorov, A., Scornavacca, C., Fujimoto, M. S., Bodily, P., Clement, M. J., Crandall, K. A., Whiting, M. F., Schrider, D. R., & Bybee, S. M. (2021). Evolutionary history and divergence times of Odonata (dragonflies and damselflies) revealed through transcriptomics. iScience, 24(11), 103324. DOI: 10.1016/j.isci.2021.103324. (ScienceDirect)
