SATURDAY, 28 MAY 2016
We’ve all heard about extinction – species lost forever but what happens when another species is entirely dependant on the one that is lost? Co-extinction, that’s what. On the flip side, now that we know what’s at stake, concerted efforts to secure the crayfish’s future will also ensure one for the tentacle flatworm. This is my kind of 2 for 1 offer.
Image & video: David Blair/James Cook University
Written by Michelle Cooper
![](mailto:?subject=The world’s worst 2 for 1 deal: Co-extinction&body=https://bluesci.soc.srcf.net/posts/the-worlds-worst-2-for-1-deal-co-extinction <div class="wp-caption caption alignright" style="max-width: 310px;"><br><br> <img src="https://bluesci.co.uk/wp-content/uploads/2016/05/Temnosewellia14_Credit_David_Blair-300x225.jpg" class="attachment-medium size-medium wp-post-image" alt="OLYMPUS DIGITAL CAMERA" srcset="https://bluesci.co.uk/wp-content/uploads/2016/05/Temnosewellia14_Credit_David_Blair-300x225.jpg 300w, https://bluesci.co.uk/wp-content/uploads/2016/05/Temnosewellia14_Credit_David_Blair-768x576.jpg 768w, https://bluesci.co.uk/wp-content/uploads/2016/05/Temnosewellia14_Credit_David_Blair-1024x768.jpg 1024w" sizes="(max-width: 300px) 100vw, 300px" width="300" height="225"> <span class="wp-caption-text"></span><br><br> </div>When you’ve evolved a specialised lifestyle alongside your host since the Cretaceous period, the chances that you’ll persist if your host doesn’t is highly unlikely. In fact, a <a href="http://rspb.royalsocietypublishing.org/content/283/1831/20160585">recent study</a> by researchers in Australia and the UK investigated the evolutionary and ecological history of the relationship. The paper’s lead author, Dr Jennifer Hoyal Cuthill from Cambridge’s Department of Earth Sciences, said “The extinction risk to the crayfish has been measured, but this is the first time we’ve quantified the risk to the temnocephalans as well – and it looks like this ancient partnership could end with the extinction of both species.”<br><br>We’ve all heard about extinction – species lost forever but what happens when another species is entirely dependant on the one that is lost? Co-extinction, that’s what. On the flip side, now that we know what’s at stake, concerted efforts to secure the crayfish’s future will also ensure one for the tentacle flatworm. This is my kind of 2 for 1 offer.<br><br><a data-flickr-embed="true" href="https://www.flickr.com/photos/simonhoyte/27193494832/" title="Video showing temnocephalan worms attached to a spiny mountain crayfish from Sydney _Video credit David Blair James Cook University by simon for king, on Flickr"><img src="https://farm8.staticflickr.com/7296/27193494832_94189280bf_n.jpg" alt="Video showing temnocephalan worms attached to a spiny mountain crayfish from Sydney _Video credit David Blair James Cook University" width="320" height="262"></a><br><br>Image & video: David Blair/James Cook University<br><br>Written by Michelle Cooper){kind=link}