It turns out that there might be something in this idea of cryptic female choice after all. By viewing the last two rows in Table 1 it is possible to see the much longer duration time of copulation for species with a spermatheca. This was present in both the virgin and non-virgin models of the experiment. Also, the females that had previously mated took much longer to copulate than females who were virgins. This would imply that the extra time was taken by the females to evaluate their mate, and to make an educated choice on whether or not they wanted to protect the sperm from other males who would try to remove it. This process would last longer in previously mated damselflies because they have had the experience to define what traits the male must have to survive natural selection. It is also independent of having a spermatheca or not, as can be seen by the Virgin vs Non-Virgin section of Table 1 because the non-virgins of each species copulated longer than the virgins did.

 

Table 1

			Virgin
Species	P.acutipennis	P. latipes	L. virens	L. viridis		L. barbarus	E. cyathigerum *
Stage 1 (min)	25.57 ± 3.82	29.20 ± 1.8	8.97 ± 0.73	6.31 ± 0.4		5.71 ± 0.84	27.85 ± 1.93
Stage 2 (min)	1.77 ± 0.09	1.55 ± 0.11	1.17 ± 0.09	1.28 ± 0.06		3.01 ± 0.29	1.39 ± 0.13
Total Time	27.87 ± 2.21	30.94 ± 1.82	12.16 ± 2.18	9.11 ± 1.29		8.76 ± 0.87	33.21 ± 2.00
			Non-Virgin
Species	P.acutipennis	P. latipes	L. virens	L. viridis		L. barbarus	E. cyathigerum *
Stage 1 (min)	65.65 ± 5.81	73.42 ± 7.67	12.05 ± 1.52	19.15 ± 1.9		9.89 ± 1.59	44.48 ± 6.05
Stage 2 (min)	2.00 ± 0.14	1.80 ± 0.19	0.99 ± 0.17	1.36 ± 0.15		2.51 ± 0.14	1.20 ± 0.10
Total Time	65.99 ± 4.89	71.37 ± 6.16	13.59 ± 1.75	19.59 ± 2.00		12.43 ± 1.57	49.47 ± 6.03
			Virgin vs Non-Virgin
Species	P.acutipennis	P. latipes	L. virens	L. viridis		L. barbarus	E. cyathigerum *
∆t** (min)	38.12	40.43	1.43	10.48		3.67	16.26
		With Spermatheca		Without Spermatheca
	Species	E. cyathigerum *	L. viridis	L. virens		L. barbarus
	∆t*** (min)		21.4
	∆t**** (min)		43.04
	* There was a third stage present that was not shown, but is included in the total time.
	** Non-Virgin minus Virgin for the time difference.
	*** The difference in total time for virgins with spermathecas and without spermathecas.
	**** The difference in total time for non-virgins with spermathecas and without spermathecas.

 

This data is then visualized in the following graphs...

Graph 1 (red refers to non-virgins and blue to virgins)

In almost every species above there is a relationship between a longer copulation and a non-virgin female.  This evidence supports the competitive nature of the males in the species.  Males extend copulation with a non-virgin female to extract another male’s sperm and to increase the amount of sperm inseminated, which ensures a greater chance for offspring.

                       

 

Graph 2

The data above shows a direct correlational between the presence and size of spermatheca and the duration of copulation. Thus, it is apparent that the P. latipes, the species with the largest spermatheca in the sample, also participated in the longest copulatory acts.

L. virens = 0 spermatheca    P. latipes = 1 large spermatheca    L. viridis = 2 small spermathecas