Embryonic development of human lice

Mar 24, 2019 • 3:54 PM UTC

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Manu Prakash

I am a faculty at Stanford and run the Prakash Lab at Department of Bioengineering at Stanford University. Foldscope community is at the heart of our Frugal Science movement - and I can not tell you how proud I am of this community and grassroots movement. Find our work here: http://prakashlab.stanford.edu

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If you have kids, you probably already know all about lice. Or maybe you think you know all about lice – and you just want to crush it. But wait, just wait a second, pull out your foldscope next time anyone talks about lice and give it a good strong look. And you can crush it afterwards. Here is a highly adaptive animal that finds a way to your head, claws on, and reproduces on your head laying eggs (nits). Now, these eggs need to develop into a full adult – on your head. And hundreds of these eggs might be developing from a “single cell” into a complex fully functional animal capable of reproducing.
The process of embryonic development is remarkable – but it’s often hard to observe since embryos are very delicate and get disrupted during observation. Not in the case of human lice; here I document the entire process of observing development and embryonic stages of human lice – and the stages are absolutely fascinating.
The first common stages I could observe while searching for lice on my kids head (probably I have them too – I just don’t know it).. it starts with a stage with loose set of cells (looks like imaginable discs) that are alive and moving around. The next stage I start seeing several set of features. It follows a stage where the lice does tremendous amount of work pumping gas into its tracheal system and also detach itself from the cuticle. In my next series of posts – I will spend a lot more time on the dynamics of this gas pumping – but for right now – enjoy the beauty of this development process. And when you are done with it – feel free to crush it if it makes you feel better.

You can read more about the common nature of head lice on the CDC site.
https://www.cdc.gov/parasites/lice/head/gen_info/faqs.html
Down below is data collected with time lapse; where I use “lapse it” as an app to collect very long time scales (maximum single time lapse collected is 12hrs). Since it takes 8-9days of development before lice eggs will hatch, I am yet to capture the hatching process. But I still was able to observe some remarkable details that I will share in upcoming posts.
Time lapse data on human lice development
10hrs in 5 sec