On ladybird ejaculation and pushing the frontiers of science

By Rebecca McLeod 09/12/2010

A few weeks ago I was flicking through a copy of the prestigious journal Proceedings of the Royal Society B, when one article in particular caught my eye – Condition-dependent ejaculate size and composition in a ladybird beetle (277: 3639-3647).

I must admit, my first thought was ’ladybird’s ejaculate?!’ I mean, they just seem so cute, and well, ladybird isn’t exactly a name that conjures up an image of a testosterone-ravaged creature. This was quickly followed by a second thought: ’How on Earth do you get a ladybird to ejaculate?’ My imagination wandered to a scenario akin to the human-assisted [ahem] ‘manipulation’ that Kakapo are treated to. Surely not… My brain must have really been firing that day, because it came up with yet another thought — and this one seemed to scream louder than those prior ’But WHY?!’. Why why why (why why why) would anyone care to learn about ladybird loving?

I don't know why I feel like this picture is so shocking - I'm a biologist!! (image from http://conservation-issues.co.uk/Gallery.htm)
I don't know why I feel like this picture is so shocking - I'm a biologist!! (image from http://conservation-issues.co.uk/Gallery.htm)

In answer to the first thought, well, yes, apparently they do. As for the second, and deep down I felt a little piece of me die when I uncovered the answer to this — they get ladybird pairs to mate under a microscope, then kill the (un)lucky lady ladybird and dissect out the ejaculate. Ohhhhhhhhh, seems so tragic! Particularly given that they used virgin females in the experiment. And as for thought number three, well this is the thing I really want to focus on today.

’But who cares?’ is a question that all scientists should have a ready answer for. A simple ’I do!’ will generally not cut it. In these days of dark economic times and funding cuts, we scientists need to ensure our funding bodies that the research we are doing is relevant to society (and if at all possible — can be turned into some kind of technological marvel that will generate zillions of dollars for the economy). I also strongly believe that members of the general public should be able to understand the value (be it social, economic, or just plain old increased understanding of the world around us) of each scientific research project that is going on — and it is up to the scientists involved to convey that.

So, back to the ladybirds, the authors of the study were interested in whether the amount and composition of ejaculate produced was related to the quality and quantity of the diet fed to each man ladybird in preparation for the final hurrah. It turns out this was a very worthwhile question to ask, as those males fed a low quality diet ejaculated smaller amounts of sperm (but they were more concentrated), and mated less frequently and for shorter periods of time than those on a high quality diet.

The authors didn’t explicitly outline the value of this research in a way that would make your Mum go ’ooooo how fabulous that I know that now’, but they did talk a lot about our current understanding of sexual selection and how these findings add to it.

It’s a big jump to go from a ladybird to a human, but all I can say is, guys, next time you have that craving for a triple cheeseburger you might want to remember this study and all those deflowered lady ladybirds who selflessly gave their lives in an effort to push the frontiers of science.

Postscript: I can hear all you scientists out there now tut tutting at my incredible lack of ‘scientificness’ — all I can say is this is one of the beauties of writing a blog over scientific articles…. You really should try it.

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