Last Updated on : Tuesday, 30 May, 2023 10:02:23 PM

Ovipositor of female dragonflies

Ovipositor or Vulvar Lamina
of Female Dragonflies and Damselflies

Female dragonflies have either one of the two method of depositing eggs from the abdomen:
1- using Ovipositor Structure
2- using Vulvar Lamina

The two methods of deposit eggs by Odonata:
DRAGONFLIES DAMSELFLIES
1- using Vulvar Lamina
(Exophytic egg-layers )

- Most dragonfly families

2- using Ovipositor Structure
(Endophytic Ovipositor)

- Dragonfly Family of Aeshnidae and Petaluridae
- All demselflies families

Exophytic eggs are laid by dipping the tip of the abdomen beneath the water whilst in flight.

Endophytic eggs are inserted into a substrate such as plant tissue.

 

These dragonflies  extrude fertilized eggs in a clump, through the genital opening in their eighth abdominal segment. The female  tap the abdomen on the water surface, releasing the cluster of eggs.

The females of all damselflies and some dragonflies (Aeshnidae and Petaluridae families) have a fully formed ovipositor, which is a complicated structure on the underside of abdominal segments 8 and 9 containing :

A) Spike like basal cutting blade (rear end of segment 8)

B) A pair of thin needle like stylus sensor in egg positioning (rear end of segment 9)

C) A set of sharp anal claws to stabilize the abdomen while the basal plate is cutting hole and inserting eggs into plant. (segment 10)

Some species have a stylus, which is a thin, needle like projection, at the end of each of the two valves of the ovipositor.

The Basal Blades of ovipositor is consequently blade like enabling the insect to cut into the plant material or other substrate.
Type 1 Dragonflies
Vulvar Lamina		 Type 2 Dragonflies
Ovipositor Structure		 All Damselflies
Ovipositor Structure
Ovipositor of a female dragonfly Gynacantha basiguttataOvipositor of a female dragonfly Oligoaeschna foliacea Ovipositor of a female damselfly Prodasineura verticalisOvipositor of a female Coeliccia octogesimaOvipositor of a female damselfly Pseudagrion microcephalumOvipositor of a female Onychargia atrocyanaIschnura senegalensisAgriocnemis pygmaeaOvipositor of a female Vestalis atropha ♀50mm
Ovipositor of a female damselfly Libellago lineata
 

♀♂

The terminal segments adult female Anax imperator, external ventral (B) and lateral (C) views.

 

Lam, basal plate基礎板of ovipositor (lamina valvarum);

V1, first valves 閥門 of ovipositor (valvulae 1);

V2, second valves 閥門 of ovipositor (valvulae 2);

V3, third valves 閥門 of ovipositor (valvulae 3);

St, stylus 觸針 =  A pair of thin needle like stylus that serves as sensor in egg positioning

 

Vulvar lamina (subgenital plate) with a conspicuous “V” incision 切口.

Bottom view of  the terminal segments of an adult female Oligoaeschna foliacea.

1) Lam - the basal plate of ovipositor (lamina valvarum);
2) V2 - second valves of ovipositor (valvulae 2);
3) V3 - third valves of ovipositor (valvulae 3);
4) St - stylus, a pair of thin needle like stylus that serves as sensor in egg positioning;
5) Spiky Anal Base - Anal base at the last segment with sharp spike that perhaps serves as anchor to stabilize the abdomen while the ovipositor is inserting eggs into plant.

 

Side view

Pair of cerci

The family of Aeshnidae has a fully formed ovipositor which is a complicated structure covering segments 8 to 10. The ovipositor is used to insert eggs into plant tissue, mud, or other substrate.
Ovipositor of a female Gynacantha basiguttata containing :
A) A spike(長釘) like basal plate that serves as cutting blade (rear end of segment 8)
B) A pair of thin needle like stylus that serves as sensor in egg positioning (rear end of segment 9)
C) A pair of sharp anal claws that perhaps serves as anchor to stabilize the abdomen while the basal plate is cutting hole and inserting eggs into plant. (segment 10)
 

INDEX OF DRAGONFLY

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