Hey
everyone
My name
is David Clarke and I have decided to make the main topic of my blog sexual
selection throughout the animal kingdom.
It will include many facets that include evolution, sexual dimorphism
and the variety of mate finding behaviour that is utilised by different
species. My plan is to give an example of sexual selection from a different
species each week with information taken from the literature.
For this
first post I thought, seeing as though this is an evolution class, I would start with
an example from back in the Jurassic, which is also an example of a very simple
way of attracting females (in animals), showing off your enlarged genitalia. In this
instance it is an extinct insect in the order Mecoptera that existed in the
late Middle Jurassic.
Scientists
discovered the fossils of two, now new, genera of scorpionfly in the
Jiulongshan formation at Daohugou village Ningcheng County in Inner Mongolia,
China. Through examinations of the specimens they found that, although similar
in size to other Mecopterans in the same era, these new specimens, Miriholcorpa forcipata (Figure 1) and Fortiholcorpa paradoxa (Figure 2) had enlarged male genitalia and
extremely long and extended terminal abdominal segments.
The scientists proposed an evolutionary scenario in which these abdominal segments were used to intimidate/compete with other males and/or were used to attract females by showing off their large “penis”. Having these large abdominal segments and enlarged genitalia could be seen to be quite a burden to carry around however as they were alive for quite a while it is thought that the sexual selection and display of these characteristics outweighed the possible poor mobility and bulky body plan in the evolutionary process.
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