Unlike any other species of flea which has been cultured successfully Spilopsyllus cumculi (Dale) is entirely dependent for its own reproduction upon its host becoming pregnant.... The ovaries of fleas kept on male or non-pregnant female rabbits remain immature whereas those on a pregnant host are mature at the time of parturition. Vitellogenesis commences at a critical point approximately 7 days pre-partum, irrespective of how long the fleas have been on the host. It is postulated that a factor required by the flea for ovarian development is only available during the final week of pregnancy, and not at all in male or non-pregnant rabbits. The factor disappears from the adult after parturition but is present in her nestlings for at least 7 days.
Pregnant rabbits have rabbit fleas
On their backs to bite 'em;
And rabbit pups have baby fleas -
And so on, ad infinitum.
On their backs to bite 'em;
And rabbit pups have baby fleas -
And so on, ad infinitum.
(Okay. So I know Jonathan Swift's version is better, but still, do you know how hard it is to rhyme Spilopsyllus cumculi with anything?)
6 comments:
The flea is called Dale? Oh dear.
The wicked flea where no man pursueth.
In its defence, it is a particularly clever flea. It can't be an easy feat, to coincide your egg-laying cycles with the fertility cycle of rabbits.
Tim has clearly never lived in a house full of women.
True. 'Twas quite the reverse in the Train family household, what with my brothers and my father, outnumbering Mum, five to one.
That's how my father grew up. Then he grew up and had two daughters and flatly refused to have more children. Wonder why.
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