Odonata of Bangladesh

The taxonomic Order Odonata is divided into three subclasses Anisoptera which encompasses dragonflies, Zygoptera that includes damselflies and Anisozypgoptera which contains intermediary species between this two groups. The Anisozygoptera suborder has only two living species and none of them are found in Bangladesh. The Latin word Anisoptera translated as ‘different wings’. The dragonflies are called Anisoptera because of their dissimilar hindwings and forewings. The hind wings of dragonflies are larger than forewings and also the shape is different. On the other hand, Zygoptera means ‘same wings’ and named so because of the similar shape and size of their forewings and hindwings. Although the dragonflies and damselflies have many similar features this two suborders can be distinguished easily by comparing some distinguishing features.

1. Dragonflies have big eyes and the eyes most often touches each other at the top of the head while the eyes of the damselflies are always separated and appears at each site of the head. (Figure 1)

Figure 1: A. Head of dragonfly - The eyes are attached at the top of the head
B. Head of damselfly - The eyes are separated

2. While perching the wings of dragonflies remain open while the damselflies keep their wings close during perching (except Lestidae family). (Figure 2)

3. The hind wing of dragonflies are larger than fore wing. Also the base of the hind wings are broader than the base of the fore wing. (Figure 2)

4. Dragonflies have bulkier abdomen while the abdomen of damselflies are long and slender. (Figure 2)

Figure 2: A. The dragonfly perch while keeping their wings open. The base of the hind wings are broader than the forewings and the abdomen is bulkier.
B. The damselfly perch while keeping their wings close. The abdomen is slender and the base of the forewing and hindwing are similar.