The Coromandel Damselfly Ceriagrion coromandelianum can be easily identified because of its bright yellow abdomen, greenish thorax and eyes. In females, the abdomen is darker with light brown colouration extending to dark brown towards the terminal end. The documentation of the reproductive behaviour of Ceriagrion coromandelianum was carried out at the botanical garden of Hislop College, Nagpur, India. The males of C. coromandelianum arrive early in the morning by 07:00hr at the ovipositing site. They belong to “sit and wait” type of mate-location. While perched and waiting for the female to arrive they at times exhibit abdominal bobbing, and oviposition posture. The territorial area of male C. coromandelianum is very small, within a range of about 45cm around his perch. There is no precopulatory courtship display and the male move toward the arriving receptive female and directly tries to form a tandem link. The other males of the group follow the pair. The tandem pair flies towards the safety of the surrounding vegetation to copulate. Before copulation, the male fills his penis vesicle with sperm material by the process of “intra male sperm translocation” which lasts for 30±8 seconds. The female curves her abdomen ventrally forward so that her gonopore which is located between the eighth and ninth sternite comes to lie before the secondary copulatory apparatus of the male and forms a strong genital link, to form the copulatory wheel. The copulation duration can be long (34–55 min) or short (12–15 min). Two stages of copulation depending upon the pumping movement of the couple can be differentiated. During the first stage, the male rhythmically and forcefully depresses and stretches the first two abdominal segments, vigorously pumping the penis inside the female vagina which accounts for 72% of the copulation duration. The second stage starts with rapid short thrusting movement which are not forceful but exhibit shallow movements of the first two abdominal segment of the male. The tandem pairs after copulation may directly move for oviposition or settle around the surrounding foliage and exhibit “post-copulatory resting” (PCR) behaviour. It is noted that 23.3% females immediately commence oviposition, 53.4% exhibit brief, while 23.3% display prolonged PCR behaviour.
The evolutionary significance of long copulation duration
in bumble bees
