Saturday, 27 October 2007

Cataulacus traegaordhi

This is the second Cataulacus collected from Abuko National Park in The Gambia (the other one was C. guineensis). I only managed to find one specimen of C. traegaordhi, so either it's less conspicuous, rarer or I just wasn't looking in the right places.

It has been found from South Africa north to Sudan, but apparently the closest it has been found to The Gambia is Ghana. Whilst finding C. guineensis in The Gambia apparently represented an northward extension of its known range, finding C. traegaordhi appears to have extended its known range westward.

Thursday, 25 October 2007

Cataulacus guineensis

At the risk of unintentionally starting a theme that could potentially be very restricting and uninteresting, I think I'm going to continue to post 'ant portraits'. Someone might actually find them useful.

This one is Cataulacus guineensis. It was collected Abuko National Park, one of the more famous protected areas in The Gambia. Abuko is a remnant of gallery forest, rather than rainforest. Despite its small size and the fact that we hired a guide (which for me meant that I didn't really have enough time to stop and collect ants), I still managed to pick up some species of interest.

Three of these, C. guineensis, Cataulacus traegaordhi and Pyramica maynei are proper forest species, so finding them in one of the few remaining pieces of proper forest in The Gambia was quite satisfying.

C. guineensis has been found in the Republic of Guinea, as might be expected from its name, and throughout west Africa, but not from Senegal or further north, so this find from The Gambia may represent the northern limits of its known range.

Monday, 22 October 2007

Gambian ant list

My long-running, rather ambitious, spare-time project at the moment is to produce a synopsis of the ants of The Gambia, as very little is known about its ant fauna. This started off from collections made by myself in 2007, from which I still have a lot of unidentified Pheidole minors, but it seems unlikely that I will be able to identify these accurately. All parts of this list are open to change, as there are very few species where I think my identifications are indisputable.

The existing list of ants of The Gambia was part of the Ants of Africa website, with a few additional species included in a checklist produced by Emms and Barnett. In combination these lists included just 21 species.

I've also borrowed some ants from Oxford University Museum of Natural History, so I will be adding the genera and species included in this collection over the next few months, as they are identified. I would be very interested to hear of any other ant specimens collected from the Gambia.

The key to the resources used is as follows:

* = collected during this survey in 2007.
T = listed by Taylor.
E&B = listed by Emms and Barnett.
OUMNH = specimens in the collection at Oxford University Museum of Natural History, collected by D. J. Mann in 1997.
NB = specimens in the Collingwood collection, all collected by Nicolas Blacker.

          rotundatus subsp. guineensis*
          luteum* (OUMNH)
          melanocephalum* 1
          atriceps (T)
          attenuatus (T)
          rufescens (T)
          affinis* (T)
          fimbriatus (T; OUMNH)
          fulvus (OUMNH)
          fulvus subsp. glabratus (T)
          maculatus* (T)
          olivieri subsp. delagoensis*
          olivieri cf. subsp. lemma?*
          rufoglaucus cf. subsp. controversus?*
          sericeus* (T; E&B; OUMNH)
          vestitus subsp. intuens*
          vividus* (T; NB): pseudogyne in Collingwood collection.
          lividus (NB): unlikely, as it is not found elsewhere in Africa.
          oasium* (NB)
          capensis subsp. guineensis* (OUMNH)
          capensis subsp. laevis* (OUMNH)
          longinoda* (T; E&B)
          E&B also list smaragdina, but this is probably erroneous.
          nigrita (OUMNH)
          emeryi*: a widespread tramp species.
          chiarinii subsp. taediosa (T)
          cf. excisa*
          gambiensis* (T)
          cf. impressa*
          impressa subsp. brazzai (T)
          wellmani (T)
          bicolor* (T; OUMNH)
          edouardi (OUMNH) 2
          sericeiventre* (T)
          brunoi (T)
          escherichi (NB)
          tarsata* (E&B)

1 See: Wetterer, J. K. 2008. Worldwide spread of the ghost ant Tapinoma melanocephalum (Hymenoptera: Formicidae). Myrmecological News 12: 23-33.
2 Queen only. Quite clearly either T. edouardi or T. tersum, but matches the description of the queen of T. edourdi better than T. tersum (= kivuense).

Sunday, 21 October 2007

Tetraponera ambigua

My Tetraponera ambigua specimens have been the subject of some friendly debate, as Brian Taylor and I have been discussing them. I noted before that they have three ocelli, albeit reduced ones, but they have particularly wide postpetioles as well.

I've now conducted a very detailed investigation, including comparing the morphometrics of my specimens with Ward's (2006) measurements, and am convinced that they fall within Ward's broad definition. The ocelli number and postpetiole width (which Ward does not include in his paper) seems to add to the overall variability of this species.

There is probably still a chance that T. ambigua is a species complex, which is hinted at by Ward. Brian Taylor suggested 'Sima ambigua Em. r. erythraea v. occidentalis Stitz 1917' as a possible identity for my specimens, which has the broader postpetiole and similar overall appearance, but is more sparsely hairy and probably lacks ocelli. Nothing so far described seems to be a perfect match for what I've got.

I often find myself thinking that if organisms such as these occurred in Europe they would have been split into dozens of species, like Lasius, Myrmica, Formica, etc. Africa probably needs the attention of more taxonomists.

Saturday, 20 October 2007

Limonium britannicum subsp. celticum

On Thursday I was lucky enough to have the opportunity to visit Hilbre Island in the Dee Estuary and saw hundreds of plants of the rock sea-lavender Limonium britannicum subsp. celticum. This would be the third rarest plant I've ever seen, but there's a problem.

L. britannicum subsp. celticum is listed in Stace (1997) as endemic to the coast from Anglesey to Westmorland. Because of this it has been considered rare and important, and was a UK Biodiversity Action Plan (BAP) species. The UKBAP has undergone a lengthy review process, the results of which were recently published. One of the changes was the removal of L. britannicum because of a taxonomic review. It's also on the 'waiting list' of the The Vascular Plant Red Data List for Great Britain for the same reason.

The only trouble is, I've been unable to find out what taxonomic changes to Limonium have occurred, as the review doesn't appear to have actually been published yet. Thanks to BioImages I know that it was discussed at a conference, but can't find any actual details. I've checked everywhere I can think of to find evidence of the review, but even the 2007 BSBI plant list shows the Limonium binervosum agg. unchanged.

As a result, this subspecies seems to be in a bit of a limbo at the moment. Presumably the people who made the decision to remove it from the UKBAP know the results of the review, even if it hasn't been published yet. Those of us who are out of the loop will presumably have to wait until then and hope that the uncertainty doesn't influence the level of threat to these plants.

From my point of view it is an even bigger deal, as it affects my 'list of the rarest plants that I've found'! For the moment I will construct it with the existing Limonium taxonomy, as follows:
  1. Ophrys aveyronensis (limited to one valley in the Causse du Larsac, France).
  2. Limonium recurvum subsp. pseudotranswallianum (limited to the coast of Co. Claire, Ireland).
  3. Limonium britannicum subsp. celticum.
  4. Ophrys aymoninii (limited to the Causse region in France).
When the Limonium review is published I may end up having to completely revise this, but I have no idea which is the next rarest plant that I've found. Maybe I'll have to try and live without a list?

Monday, 15 October 2007

Blog Action Day

Since today is blog action day I've been racking my brain trying to think of something to write. To be honest, I've found myself thinking that I should have waited a couple days before creating this blog.

Why so hard? I guess it's too difficult to summarise the problem. Plus, as an ecologist, it would be nice to think I had an answer, but I don't.

What I've decided to do is focus on what I think are the three main threats to the environment:
  1. Pollution.
  2. Climate change.
  3. Large-scale species extinction.
Worries about pollution have been around for about as long as civilisation I guess, but it still hasn't gone away. Fortunately, in the West at least, we're now pretty good at keeping on top of the problem - for every new pollutant we seem to be able to find a way of dealing with it, when enough money is thrown at it. We're even starting to think seriously about dealing with greenhouse gases, even though we don't know whether it's too late or not. If we're clever enough to create the problem we ought to be clever enough to fix it, though perhaps we need a little incentive first.

Climate change is probably the most prominent environmental catastrophes on the horizon. Obviously, this is caused by pollution, but I've listed it separately as it seems probable that eliminating pollution will not solve the problem of climate change on its own. Most evidence suggests that climate change is already upon us and will happen anyway. But let's not get too depressed: we've done some remarkable things throughout history and this problem is simply a matter of physics and chemistry. One imagines that it can be fixed, though there is very little incentive for governments to do this until it starts winning votes.

The third threat is the most serious of all. We've known for decades that we are responsible for one of the six major mass extinction events that this planet has ever experienced. The vectors for this are varied, and include pollution and climate change, as well as habitat destruction, population growth and exploitation.

I'm not convinced that we're doing much about it though. Sure, the panda's still with us and the tiger has just about managed to hang on (but who knows for how much longer). We've stopped whaling, nearly. We literally brought the Mauritius kestrel back from the brink. We perhaps feel that we've learnt from our experience with the dodo.

However, as with so many things, it is the little things that really matter - in this case 'the little things that run the world', to quote E.O. Wilson. Whilst we may feel like we do enough to protect the furred and the feathered, even the scaly and cold-blooded, we do ignore everything else. I'm not just talking about arthropods, but bacteria, viruses, fungi, etc., the things we know very little about.

'Well', you might ask, 'that's all very well, but what does it matter if we lose some of these things?' The problem is that we don't know at what point it will matter. We have named perhaps a tenth of all the species on the planet, and know precious little about that tenth. We don't know what will happen when one species, ten species, one hundred species are removed from an ecosystem, or what effect the changes to that ecosystem will have on us. We can see what effects losing entire ecosystems has though: increased flooding, extreme climate events and desertification to name a few.

Here's the key point though: when we've lost these species we're sure as hell not going to get them back!

'Ah', you say, 'but we can sample their DNA and bring them back from extinction once technology has moved on.' This is true, but to do this for every species, including those we do not know, would be an impossible task. Even if we were able to bring back every species alive today, we'd have no idea how to put the ecosystems they formed a part of and need to survive back together. Besides, our civilisation would need to survive long enough to do this. Quite frankly, we could ignore this mass extinction to the point where we realise: it's too late - we're screwed.

I've already mentioned him once: a few weeks back I found a video of E.O. Wilson talking about the same thing. He's much better informed than I am, so I strongly recommend it.

I'll leave the environmental solutions for another day, maybe.

Sunday, 14 October 2007

It begins... Plus Tetraponera claveaui

I've decided to start a blog. I'm not entirely sure why.

I've decided that this is going to be mostly about ants, as these are what I spend most of my spare time studying. Mostly this is taxonomy, but I hope as things progress it will move into other subject areas as well. There will probably be the occasional general ecology posting as well, as that's what I do for a living.

To start the ball rolling: I appear to have rediscovered Tetraponera claveaui. This species was first collected in Senegal around 1913. It was described by Santschi and appears not to have been found since. I collected about 7 workers from an Acacia pod in The Gambia.

Brian Taylor has produced a photomontage from my images for his online guide to the ants of Africa, but my attempt is shown here.

I also collected T. ambigua in The Gambia, which is a much more widespread species in Africa. It seems to be incredibly variable, but some of my specimens appeared to have three ocelli, which is not included in the variability described by Ward (2006).