Many people who see a damselfly think that it is the young one of a dragonfly, but this is not true. The two are related though, as they both belong to the order Odonata, meaning toothed ones. ‘Devil’s darning needle’ is one of the many names given to damselflies – apparently, there is a myth that if children are naughty, damselflies seek them out at night and sew their mouths together with their claspers. What led to this myth may not be known, but it is understandable why an organism that has been in existence for over 250 million years, with amazing life-history and predatory qualities, conjures up such emotions and tales.
Grouped under the sub-order Zygoptera (Zygo – paired & Ptera – wings, in Ancient Greek), damselflies can be best told apart from their larger cousins, the dragonflies, by their slender build, a habit of keeping their wings folded, and widely separated eyes. As the name Zygoptera suggests, damselflies’ two pairs of wings are identical in shape and size, unlike in dragonflies, where the hind-wings are larger than the forewings.
As with the case of dragonflies, Karnataka’s damselfly diversity too needs detailed explorations. The various eco-zones of the state, especially the Western Ghats, are sure to hold much more diversity than what has been documented. Further, with anthropogenic pressures, the diversity and abundance of species is thought to have changed since the original work done by the British. Considering that odonates are excellent indicator species, a robust documentation and monitoring mechanism in the present will go a long way in not only helping us understand their diversity, but in revealing what is happening to our surroundings.
We will now look at some of the interesting behavioural traits and species of damselflies found in Karnataka.
While sexual dimorphism is quite common in odonates, damselflies take it to a different level altogether, with polymorphism exhibited in some species. It is the female of the species which shows this character that has evolved due to various factors; it assists her in survival, hence ensuring the survival of the next generation. A few species like the White-Dartlet (Agriocnemis pieris) have three morphs: the typical female, a red morph female, and a female that resembles the male (andromorph).
Damselfly males are very territorial and aggressively defend their territory. Males employ various means to display their presence to other males as well as to members of the opposite sex. This includes fluttering of wings, abdomen bobbing, display of brightly coloured body, legs or wings, hovering, and darting flight, to name a few.
Mate guarding is behaviour exhibited by males during the post-copulation period, when the female is ready to oviposit (lay eggs). Two kinds of mate guarding are seen: the one in which the male hovers over the female as she lays eggs and drives away any intruder is termed as non-contact mate guarding, while the other, in which the male remains in tandem with the female until she has completed egg-laying is called contact guarding. This behaviour has evolved as a response to other males picking up unguarded females after mating and replacing the sperm packets of the earlier male with their own.
All damselflies lay their eggs inside plant-tissue. This is referred to as ‘endophytic oviposition’. The plant can be a submerged or emergent aquatic plant or simply a dry floating twig. Females use their specialised ovipositors to make a slit in the plant tissue and insert their eggs.
During egg-laying, some species of damselflies are known to submerge under water for as long as 30 minutes. After mating, once the female has chosen a plant to lay eggs, she perches on it and gradually moves downwards until she is completely submerged. This behaviour has probably evolved to escape harassment by other males, which can pick up an unguarded female.
While most damselflies species fold their wings along the body when at rest, the group called ‘spreadwings’ is an exception. As the name suggests, they perch with their wings half-open. They prefer marshy areas with aquatic vegetation as well as grassy habitat.
Nilgiri Torrent Dart (Euphaea dispar)
This is a beautiful species of hill-stream damselflies endemic to the Western Ghats. It occurs north of the Palghat Gap, but is not sighted in Uttara Kannada, making it a highly range-restricted species. The males of this species can be easily distinguished from other Euphaea species by the small black tips on the apices of their forewings.
Myristica Sapphire (Calocypha laidlawi)
This is by far the most beautiful of Western Ghats’ damselflies. It is endemic to the Western Ghats and rare in its occurrence. As the name suggests, it is partial to streams in myristica swamp forests. The species was first described from around Coorg and mentioned as “confined in South Kanara District to the network of rivers about Sulia”, but very few records exist as of today from Karnataka.