Diapause and Diminishing Diversity

Capreolus capreolus, aka the roe deer, is native to the UK and can be seen in good numbers in the Fens. During an evening stroll there in July I encountered several. As well as being delightful to look at they have some interesting reproductive biochemistry. The roe deer rut takes place in July and August but the fawns are not born until the following May or June, nearly a year after the rut. The length of roe deer gestation had puzzled zoologists for a very long time and then they discovered that the roe undergoes delayed implantation, or ’embryonic diapause‘.

A roe deer peering at me as I meandered around Wicken Fen

But that wasn’t the end of the story. It was assumed that hormonal messages from the mother would tell the dormant fertilised egg, or ‘blastocyst‘ when it should implant into the endometrial layer of the uterus, but the search for the maternal hormonal trigger which has been observed in other mammals drew a blank. It transpires the trigger is a novel mechanism whereby the embryo, which at that stage consists of around 30 cells and has its own internal timer mechanism, secretes a messenger molecule called ‘rdPAG’ (roe deer Pregnancy Associated Glycoprotein) which precipitates a maternal hormone cascade of oestrogens that initiates the second stage of the pregnancy with implantation of the embryo. This is a remarkable piece of biology because it is orchestrated by the embryo, not the mother, and ensures the fawn is born during the favourable weather conditions of the summer thereby guaranteeing it sufficient time to prepare for the winter.

A visit to Wicken Fen always provides multiple unique photographic opportunities such as this pair of grey herons whose paths crossed, almost on a collision course:

Wicken Fen was mentioned in a BBC News article a couple of days ago about the importance of the Fens as a wildlife haven. The article is about a study into the biodiversity of fenland since 1670. Apparently, since the start of the study period 100 species of birds, bees and butterflies have been lost from the Fens and in total 504(!) rare species have not been recorded there in the last 25 years. A moments comtemplation on that rate of biodiversity loss is terrifying, and the implications of it even more so. It boggles my mind that the political decision makers, who are aware of all the environmental devastation, don’t appear to give a damn about it. Or at least not enough to want to do anything about it.

Despite that the Fens are still a very important refuge for endangered species, which I can vouch for based on my observations made whilst wandering around Wicken. The Fens are much maligned but are a unique and important haven for many species of all kinds of wildlife.

In order to manage and maintain the flora of the Fen which then provides shelter and sustenance for a multitude of other species, horses and cattle have been installed there, one of which is this magnificent chap:

This image doesn’t really do him justice, he is absolutely enormous – like a minibus on legs!

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38 responses to “Diapause and Diminishing Diversity

  1. I am completely fascinated by this concept of the “embryonic diapause.” Your photograph of the roe deer is beautiful, as are the other two images you’ve included in this post. I’m so sorry to read this sad report of the devastation to the Fens and the terrible loss of life and biodiversity there.

    • The diapause is an amazing adaptation in the roe deer because it’s regulated by the embryo itself. So I think it probably evolved in this species in response to the timing of the rut rather than variable environmental conditions, in which case I think it would be regulated by the mother.

      Only a very small percentage of Fenland remains compared to 100 years ago because the need for sedge harvesting is no longer there now that we don’t use thatch for roofing. The Fens are incredibly biodiverse and one chink of light is that my local Fen (Wicken) have a hundred year plan to massively extend and this would make it one of the biggest areas of fenland in Europe. Fingers crossed.

  2. Kangaroos have that very same most interesting embryonic adaption. It makes perfect sense here in Australia where often conditions are incredibly difficult for the native wildlife that they should be able to judge a season to justify the energy required to produce offspring and their chances of survival in our harsh conditions. I never noticed much about birds until we moved to our 4 acres out in the bush. I used to feed the magpies, starlings, sparrows and noisy minor birds here despite most of them being viewed as vermin (aside from the magpies and noisy minor birds that are native species) but out here we get blue wrens, robins, cuckoo shrikes and all sorts of other amazing native birds that come to inspect our home for insect life and that invade the garden at regular intervals. Only yesterday we had the native enormous black cockatoos sitting in a recently liberated protea that had been hidden under overgrown weeds and the cockatoos were plucking the flowers from the shrub and eating the base of the flower. We recently removed a lot of hakeas from the property that had died and apparently the black cockatoos were NOT amused and have decided to wreak havoc on the garden instead. We have a pair that breed and nest in the back bush block and they bring their babies down to the main garden to feed. It’s lovely to see these wonderful birds doing their thing as we do ours :).

    • Now that is interesting about diapause in the kangaroos – in the roe deer it is controlled by the embryo which works for an animal that is dealing with constant climatic conditions (so far!). So I wonder if in the kangaroo the diapause is also regulated by the embryo or by maternal hormones in response to prevailing environmental stress?

      I can’t believe the birds are regarded as vermin! Do they do a lot of damage? I guess your non-native species were introduced from Europe by colonists? They’d have to fly a hell of a long way across the ocean to get to Tasmania! I don’t know if you’ve seen about the recent tagging experiments where modern tags can be attached to very small birds, and we’re finding out lots about our birds which we didn’t know before. E.g. We’ve recently discovered that the cuckoo is only here for a few short months before overwintering in the rainforests of sub-Saharan West Africa. And we used to think that some of our blackcaps migrated to Africa in the autumn and some overwintered here. But we now know that all our blackcaps head off to Africa but there is a population in Eastern Europe; Poland, Ukraine etc which head west to us in the winter and replace our summer ones.

      • The bird species that I mentioned were indeed imported by homesick expats to Australia but one of the most iconic birds that symbolifies Australia and that most people would think of Australia when they saw one…the kookaburra, isn’t native to Australia either! It would be very interesting to see where our birds go. We have a very interesting twin sort of relationship with Chile in South America. Steve and I are studying horticulture and found a fellow horticulturalist who is incredibly passionate about plants, especially conifers, like we are and we have all been noting the similarities between our Tasmanian native plants and those in Chile. It is thought that Gondwanaland had Tasmania united with Chile and it’s amazing how similar our climates and our unique endemic plant life actually is. Thank you for having such a wonderful blog by the way. I am really going to enjoy reading your posts now that I found the blog through Argyle socks 🙂

      • That’s remarkale about the kookaburra, I thought it was as quintessentially Australian as oak trees are quintessentially English. Do you still have species of flora in common with Chile? It must be an awfully long way for species to travel under their own steam.

        I’m very pleased you like the Naturephile, I’m looking forward to joining you on the Road To Serendipity too!

      • Yes our endemic Tasmanian flora are incredibly similar to those in Chile. We have a very rare groundcover conifer that has an exact twin in Chile and so much of their flora is like ours that you can’t deny a common link. I was surprised about the kookaburra thing too when I found out. It’s a native to Africa. We have some amazing birds here in Australia especially our cockatoos and parrots and it’s lovely to see them visiting our garden and watching them drink water from the series of water bowls that we have installed specifically for them.

      • I know there are some big kingfishers in Africa but I didn’t know the kookaburra was one of them. I saw a nature show last year from a watering hole somewhere in Australia where there were tens of thousands of budgerigars flocking around, it was a fantastic sight. I’d love to see parrots and cockatoos in my garden!

      • It’s amazing to see them because they come right up to the hakeas near the gate near our house and the black yellow tailed cockatoos are ENORMOUS. If you managed to touch one you would be rewarded with a severe dearth of fingers!

      • Wow, how big are they? I didn’t know they were capable of amputations!

      • Using the old imperial they would almost be 3 feet tall from head to tip of tail. Steve had a captive rare black and red cockatoo in love with him at a bird sanctuary when we lived in Western Australia. Whenever she saw him she would preen and cluck and call him over to talk to her. He could scratch her head and she would snuggle up to the bars but if I came anywhere near her she would start to make warning sounds! I guess some people have it…some don’t! 😉

      • Blimey, they really are huge. I wouldn’t to be in your boots as a love rival when the opposition was that size with a nutcracker beak to go with it.

      • Yeh…I stayed WELL away from her! I wonder what it is that made her love Steve so much? He was an original punk so maybe she could recognise a fellow quiff lover from a mile off? 😉

  3. What a fascinating post… I wish cows were able to control their reproduction in the same way as deer so that farmers couldn’t manipulate the timing so that calves are born in the depths of winter, and have to survive without shelter in our rather callous NZ farm industry.
    And how utterly depressing about the threatened loss of yet more protection for wildlife in UK .
    You ‘re doing a great job telling us about these things.thank you

    • I turned vegetarian 24 years ago specifically because of the abuses that farm animals are made to endure, it’s gruesome. I wish we could return to proper seasonal patterns of eating, then so much of the abuse would be rendered unnecessary and we’d all be a lot healthier too.

      The most gratifying thing about blogging is knowing that good folk like yourself, from all around the world, are enjoying reading about the wildlife and seeing the pictures!

      • Me too, and I’ve stopped eating fish too, having learned about the awful way they die. Just organic chicken very occasionally.
        .I regret that I do want to eat dairy, because I really hate the way the dairy industry works…
        I don’t mention it any more to people, as I hate causing a fuss, and seeing people bend over backwards because “I’m special and different”!, but I notice that if I do eat meat when I’m with friends, the arthritis in my hands protests later…
        I love reading your blog, and seeing the pictures…

      • Mechanised live stock management is a really ugly business. I’m afraid I’ve been more selfish than you and I’ve insisted that I don’t eat meat. But you have a sound medical justification for avoiding so I think you’re very noble for suffering it!

        I’m very pleased you enjoy The Naturephile. I saw from your last post on 09/11 that you’re easing off on the blogging. I hope your husbands health improves so you can resume all your normal activities.

  4. Pingback: Mammal embryos that bide their time | Science on the Land

  5. What in interesting and informative post. I’m going to link to it from my own blog.

    What’s the Bill to allow landowners more commercial exploitation of land? You’re right to say that it’s not appearing in the mainstream news – I’d never heard of it until your post here.

    • I don’t know what it’s called but it was in the broadsheets last week – it’s the one where the Tories are deregulating planning so their monied friends can develop greenbelt and even National Park land. And the Lib Dem lapdogs seem to be letting them get away with it!

      Oh dear, I appear to have betrayed my political leanings. I do apologise, I couldn’t help myself 🙂

      PS Thanks for the pingback

    • It’s called ‘The Growth and Infrastructure Bill’ and I just found this: ‘http://wtcampaigns.wordpress.com/2012/11/05/the-growth-and-infrastructure-bill-what-does-it-mean-for-the-natural-environment/’ at the ‘Woodland Matters’ blog from the Woodland Trust. See what you think.

      If, after reading it you think that our government are perhaps not on the side of the average voter, check this out: ‘http://www.bbc.co.uk/news/uk-politics-20328297’. It’s an article by Roger Harrabin that’s tucked away in the BBC News ‘Science and Environment’ page.

      • Thanks! It’s late now for me (I’m a morning person) but I’ll read these links in the morning and they’ll probably inspire a new blog post. Hope this won’t mean I’m stealing your idea: your blog mostly isn’t political so I think you weren’t planning to write about planning. Btw my political leanings aren’t the same as yours but like you, I try to keep party politics off my blog. Let’s talk science instead 🙂

      • Point taken. I guess that did come across as a tad party political. It wasn’t meant to be, I loathe politicians of all hues!

        But I reckon some of the scientific issues are so big now they are intrinsically political and not so easy to disentangle. I hope the links are of interest though.

        PS You won’t be stealing my post, your blog is a much more appropriate forum for a discussion on planning than mine. I’ll look forward to reading your comments.

  6. Interesting and compelling as always, Finn…thank you.

  7. That shot of the two herons is marvellous! I’ve never seen such a sight before. The roe deer story is amazing too, is it only roe deer that have this reproductive business, or other deer as well?

    • Hello Lorna, many animals are able to do this, it can be a response to environmental factors including lactation which ensures a female doesn’t become ‘fully pregnant‘, as it were, until the current brood is weaned, to avoid any overlap. The only other deer species I could find a reference to was Père David’s deer, which is a deer of the marshes of southern China and according to the IUCN redlist of 2008 is extinct in the wild. So I guess ED didn’t work too well for them (either that or they just taste too good!)

      • I’m sad to hear about the Pere David’s deer. They were my favourite animal on a trip I had to Edinburgh Zoo many years ago, they’re such magnificent animals. There are a lot of red deer up this way, and I passed three young males the other day quite close by in a field. They never cease to fill me with delight, it feels like a real treat to get close to them.

      • That’s another reason I want to go to Scotland – I’ve never seen a wild red deer and I’d give my eyeteeth to see one!

      • They are splendid beasts. Walking in woods around here I quite often startle a female but the males seem to be less visible. I did nearly drive into one last winter on a quiet road, but thankfully its eyes glowing in the headlights alerted me to it in time. They can cause quite a bit of damage if you hit them, and of course it doesn’t do them any favours either. I hope you get to see some in the wild some day. You’d have a very good chance of seeing herds of them if you came up this way in the cold weather when the snow drives them down to lower levels.

      • Hello Lorna, I’m glad you missed it!

        I’ll definitely get to see red deer one day, it’s a mission, along with pine marten, crossbill, ptarmigan and lots of other beasties that can only be found in the UK in your neck of the woods.

  8. Wow, what a photo of the herons!

    Here too, politicians are ignorant of environmental issues at best. At worst, they seem to hate not only environmentalists, but the actual environment.

    • Same here. Our government is currently in the process of sneaking a bill through parliament which will hand over a frightening amount of power to landowners to facilitate commercial exploitation of grenn areas which have previously been untouchable. All the ministers in the current government are wealthy and can afford to live in areas which will be relatively unaffected by this, so they simply don’t care. (The only thing they understand is money – they know the cost of everything and the value of nothing!).

  9. This is so interesting – thank you!

  10. Interesting photograph of the pair of grey herons in flight. It simulates a movement that visually appears upward for one heron and downward for the other. Thus, avoiding the collision course.

    • I guess they’re not quite as close as the camera makes them look, but by eye they looked pretty close too. I thought it was fun to see them crossing so close but going in completely different directions.

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