For some time now, I’ve been meaning to write a blog post about one of my favourite papers: Leigh Simmons and Doug Emlen’s research into evolutionary trade-offs between weapons and testes. It’s a fascinating piece of research, encompassing an ingenious experiment and a broader investigation of metabolic trade-offs in male dung beetles of the genus Onthophagus.
I’m afraid, however, that I’ve fallen foul of the temptation to post about it on my tumblr site, so that I could take advantage of a great photo of the beasties themselves. Don’t worry, however – with a single click of your mouse, you can nip over and read it right now…
As I have alluded to before on this blog, I am really interested in the work of Prof Marlene Zuk and her collaborators on the response of cricket populations in Hawaii to an invasive parasitoid fly – well, it involves sexual selection and crickets, so why wouldn’t I be? But we shouldn’t forget that the behaviour of the fly itself is very cool, as it uses the mating call of the male cricket to zone in on potential hosts. Even more impressive are those parasites which actually manipulate the behaviour of their hosts, exhibiting a kind of ‘mind control’ over their victims.
Over at ‘The Scientist’, there is a really nice in-depth article of research going on in various systems, which I definitely recommend:
The cartoons provided there are very nice, but it does strike me as a little strange that no photographs or video links are included – perhaps they worried that their readers are a little squeamish? Well, never fear, strong-stomached science pals – I have provided a video here of how the jewel wasp turns a cockroach into a chitinous bargain bucket for its larvae! A word of warning, however – it is from the History Channel. Thankfully, even their horrendous presentation style can’t ruin the sheer awesomeness of a wasp paralysing a cockroach, then injecting its brain with a MIND CONTROL SERUM (that’s not really what it is, I just wanted to write it), and then… well, you really should watch the video.
If all that has you fearing of a potential zombie cockroach apocalypse, then perhaps help is on its way… researchers have discovered an ‘antidote*’!
Combining the format of readers’ tips pages from crappy magazines, as popularised by http://lifedeathtoptips.tumblr.com/, with little blasts of interesting animal titbits (see the ever-awesome Ed Yong’s http://naturewantstoeatyou.tumblr.com/ ), I hope that this might amuse / entertain / interest a few people. I also thought that, given I’m moving into the final year of my PhD, it’s probably best if I can do something that takes a little less time to prepare.
Of course, I’ve since found that it takes me ages to create the obnoxious images that I use to illustrate each post. I’m an idiot.
Apparently North Carolina State University has an official research blog (called ‘The Abstract’), which is a pretty great idea. One of the newest posts is by a post-doctoral researcher named Michelle Trautwein, who has written a nice overview of a review paper that she (and several co-authors) have just had published in the 2012 Annual Review of Entomology.
Unfortunately I don’t have access to that journal, but I recommend you read the blog entry to find out some interesting facts about dragonflies, termites, and the latest findings as regards insect evolution…
The problem with scientists is that we like to meddle. We like to squeeze and push and pull and stretch; to manipulate things to see what will happen. The thing we’re good at is meddling to answer a question, and to meddle in a controlled and precise enough fashion that we can quantify the results.
When it comes to investigating animal behaviour, this often involves looking at the range of responses to a particular stimulus, or how the responses change as the stimulus is altered in a specific way. This can be reasonably tricky to execute, and the problems pile up when investigating sexual interactions – precisely because, as the adage goes, it ‘takes two to tango’.
Ever since Malte Andersson’s classic scissors-and-glue-based meddling showed that female choice favoured male African long-tailed widowbirds with elongated tails, interest in how females respond to experimental manipulation of male ornaments and displays has skyrocketed. However, before manipulation can take place, the character itself must be understood. This may seem reasonable when considering the length of a large passerine tail, but what about displays that are ‘multi-modal’ – ie, elaborate combinations of tactile, visual, and acoustic signals? For example, the courtship dance of this tiny, colourful peacock spider, Maratus volans:
Evidently, this is a very complex display, and requires careful quantification before we can begin to understand differences in female responses. Small invertebrates make good laboratory organisms as they are easily looked after in larger numbers, but that does not necessarily mean that they are cooperative. While high-speed video and laser vibrometry is available for such studies, this requires that the males perform – and that females don’t get so excited that they ruin it all by being a little too eager. Thankfully, as the Elias lab at UC Berkeley discovered, the males can be a little… well, it’s perhaps too easy to anthropomorphise here, but… thick? Or perhaps just desperate? Whichever it is, I’m sure the watching scientists were only too happy to find that males would engage in their rather charming display for a dead, pinned female.
Now, having this information is only part of the battle. While we may be able to quantify these kinds of displays, how is it possible to manipulate them? Signals with fewer components still present serious challenges – for example, the male túngara frog Physalaemus pustulosus emits a loud mating call, but does so in groups while females watch. The call may consist of a simple whine, or a whine with multiple chucks appended, and is accompanied by the inflation of the large vocal sac. In order to determine which is the dominant signal, researchers must be able to manipulate each of these components – but how?
Well, robotic sex frogs, obviously.
These robotic sex frogs – “hereafter referred to as robofrog”, as probably my favourite ever line in a scientific paper’s methods section states – enabled the Ryan lab at the University of Texas, Austin, to investigate the importance of realistic visual stimuli alongside acoustic signals. Previous work had shown that females prefer the complex call (incorporating both whine and chucks), and Taylor et al found that adding the visual stimulus of the expanding vocal sac led to higher female preference – but only under relatively low sound pressure levels. These levels are determined in part by the distance from the female to the male, the number of males participating in the frog chorus, and interference from overlapping calls. Perhaps this visual component helps females to detect where a male is, and assign the call to him?
Taylor et al used their total control over the robofrog to spatially and temporally separate the acoustic and visual components, and observe female responses. In layman’s terms, they played the mating call so that it did not match the position of the robofrog; they also performed a separate experiment in which the call was played such that it did not match the inflation of the robofrog’s vocal sac. Their results show that females exhibit a significant preference for the call over the visual cue, the vast majority approaching the speaker rather than the robofrog. They also discriminated strongly against a call that was not in time with the robofrog’s inflation.
So what does this show us? Well, given that the call is both necessary and sufficient for mate attraction, it is interesting that the production of this visual cue can have such a strong influence on female response. If a perceived difference in timing can alter preference, this indicates that females may be using this to discriminate between males engaging in a noisy frog chorus. Meddling with characters in this fashion helps us to investigate how and why traits and preferences have evolved, while using robotics in this setting enables us to experimentally disentangle individual components of complex sexual traits. They also give us the slightly less useful insight that, if you ever want to make a successful sex robot, you’d better make damn sure that it’s good at lip-synching.
Andersson M (1982) Female choice selects for extreme tail length in a widowbird. Nature, 299,818–820.
Girard MB, Kasumovic MM, Elias DO (2011) Multi-Modal Courtship in the Peacock Spider, Maratus volans (O.P.-Cambridge, 1874). PLoS ONE 6(9): e25390.
Taylor RC, Klein BA, Stein J, Ryan MJ (2010) Multimodal signal variation in space and time: how important is matching a signal with its signaler? J Exp Biol 214, 815-820.
This post has been entered in a competition at http://www.nescent.org – the National Evolutionary Synthesis Center is offering travel grants for ScienceOnline2011 for the best evolution-themed blog post.
As this blog is ostensibly about evolution and sex (and pretty pictures), I should probably bring your attention to National Geographic’s photo gallery of some newly-discovered deep sea worms. These are enteropneusts, or acorn worms, and feed mostly in a similar way to earthworms – by swallowing mud from the sea floor, and extracting any tasty matter. However, some of these worms can also feed on material that is suspended in the water, using cilia to suck it into their mouth.
The cool thing about these recent discoveries is finding out how these worms have adapted for life in the deep ocean – the most striking feature being the ‘big lips’ that they use to get more food, and get it faster. Some are also able to create ‘mucous balloons’, enabling them to float upwards and get these big lips around some waterborne snacks!
Also, unlike earthworms, acorn worms belong to the phylum Hemichordata – meaning they are some of the closest living phylogenetic relatives of both chordates and other invertebrates. Evolutionarily speaking, they are more closely related to you and I than to the earthworms you’ll find in your back garden…
You may be wondering how any of this ties in with sex at all. Well, it doesn’t, really. It was more that the pictures in the photo gallery linked below makes them look like an array of rather horrifying sex toys. Enjoy!
I must admit to having developed a soft spot for them over the time I’ve been living here; at first they infuriated me, as they drove all the smaller birds away from our window feeders, but I then learned that they – like sparrows – were suffering huge declines in numbers. It’s also been a delight to watch the juveniles develop from squawking balls of brown fluff into sleek adults, with their purple and green iridescence.
“Every one of us is, in the cosmic perspective, precious. If a human disagrees with you, let him live. In a hundred billion galaxies, you will not find another.”
― Carl Sagan, Cosmos
“How is it that hardly any major religion has looked at science and concluded, “This is better than we thought! The Universe is much bigger than our prophets said, grander, more subtle, more elegant?” Instead they say, “No, no, no! My god is a little god, and I want him to stay that way.” A religion, old or new, that stressed the magnificence of the Universe as revealed by modern science might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths.”
― Carl Sagan, Pale Blue Dot: A Vision of the Human Future in Space
“The earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that in glory and in triumph they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of the dot on scarcely distinguishable inhabitants of some other corner of the dot. How frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity – in all this vastness – there is no hint that help will come from elsewhere to save us from ourselves. It is up to us. It’s been said that astronomy is a humbling, and I might add, a character-building experience. To my mind, there is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly and compassionately with one another and to preserve and cherish that pale blue dot, the only home we’ve ever known.”
― Carl Sagan
I follow an account on twitter that simply crawls the site, retweeting any posts featuring words like ‘evolution’, ‘Darwin’, ‘natural selection’, etc. Sometimes this brings up interesting articles; sometimes the article will be more like ‘the evolution of ’s wardrobe’. More regularly than you would have hoped, however, this account will point me in the direction of something anti-evolution. I try not to pay too much attention to them, as they generally combine the none-too-alluring facets of being poorly-researched, disingenuous, and flat-out batshit insane. The other day, one cropped up entitled ‘Darwin’s Diabolical Delusions’ – how could I fail to click through to something with such an alliterative and ridiculous title? Happily, the content did not fail to deliver on the usual counts.
The article itself is written by Ellis Washington and posted on ‘World Net Daily’, a website which appears to offer a right-wing, conservative Christian take on a variety of issues. This is very much in opposition to my own outlook, but my criticisms run a little deeper than political ones – which, ideally, would be irrelevant in a piece which purports to be about evolution. However, as the current situation in the USA testifies, science seems to be worryingly high on the list of things to denigrate for those wishing to be seen as serious contenders for the Republican presidential nomination. For a good overview of this, see Tom Chivers’ recent blog piece here. Strangely enough, this appears in the website of the Daily Telegraph, a British newspaper which holds a not dissimilar political viewpoint to WND, and counts professional troll James Delingpole among its more ‘celebrated’ bloggers. (I should warn readers now that straying too far into the comments of Chivers’ blog should be avoided if they wish to retain any vague semblance of sanity).
Washington’s drive in this article is to inform the reader of how the ‘Darwin Gestapo’ retains control of academia, suppressing the courageous few ‘Intelligent Design scientists’ – anyone thinking that such a term may be oxymoronic would be cowed by the information that Darwin’s seminal work is not just ‘diabolical’, but also ‘anti-scientific’. Warming to his theme, Washington notes that the theory of evolution’s ‘primary purpose’ was not scientific, but rather “to infuse education atheism [sic] throughout every conceivable aspect of culture and society”. Washington does admit that he is not a scientist, and presumably hopes that neither are his readers – nor must they possess the skills to carry out a simple internet search for ‘big bang theory’, else they might find fault with his assertion that this was simply an ‘explosion’. His simplistic reasoning seems to be that ‘bang’ means ‘explosion’ and explosions ‘destroy things’, therefore a ‘big bang’ could not have created matter. Following this method of creating a linear narrative where none exists, he puts forward the familiar – and untrue – trope of how all of the 20th century’s tyrants have used ‘Darwinian philosophy’ as justification for genocide. So far, so predictable.
However, the meat of Washington’s article lies in the way that proponents of intelligent design or creationism are treated by their supposed peers – for example, a recent case in which ID advocate Dr Granville Sewell “unfairly had one of his papers unjustly rejected” from a mathematics journal. The blog ‘Retraction Watch’ paints a somewhat different account of the affair, noting that the paper had initially been made available as part of the journal’s ‘rapid publication’ system, and was then removed upon further inspection of its content after complaints were made. The article had been peer-reviewed, and journal has made it clear that the removal was due to philosophical arguments rendering it unsuitable for a technical journal, rather than for any factual errors. One would have imagined that Washington, being a lawyer, would be aware of the distinction between ‘rejection’ and ‘retraction’. It should be noted that, while the journal has apologised to Sewell and paid a settlement, this was for “any inconvenience or embarrassment that may have been caused by their unilateral withdrawal of his article”, and does not change the status of the paper itself. Evidently, Washington hopes that his audience will see this as yet more proof of the “Gestapo tactics of the Darwin lobby”, rather than considering whether a paper providing the same mathematical content without the blanket of religious philosophy may have been considered more suitable for publication in ‘Applied Mathematics Letters’.
Of course, this winding road leads us to the true gripe of our plucky hero – that he himself has had various papers rejected for reasons he no doubt sees as both ‘unfair’ and ‘unjust’. He claims the fact that he had to resort to publishing one article in a Romanian journal as ironic – somehow conflating the more forgiving nature of a low-ranking Eastern European journal, the devastating history of a Communist tyrant, and his own personal views on how Darwin’s theory is directly responsible for genocide into one vast cosmic joke at his expense. In no way could it be that a man whose inability to grasp basic tenets of science (or, indeed, simple internet searches), coupled with paranoia, repetitive and redundant phrasing, and the desire to bookend articles with quotes from Ann Coulter and Dan Brown, makes him a less able author than he believes himself to be.
As usual, my posts about how I’m ‘just about to post more’ have come to nothing, but I have an actual reason this time… my new experiment is drying up due to unforeseen cricket death, so I’ve been restarting it again while panicking over what might have caused such widespread destruction! Our first thought was that it was cricket paralysis virus, which has had a few outbreaks in the past (generally in places which rear crickets in bulk as livefood for reptiles etc), and has even led to businesses going under and people declaring bankruptcy. However, the stocks seem to be fine, so we’re of the opinion that some stress has caused the crickets to start popping their clogs early. I’m going to see how this new batch goes, and implement a few new things as regards cleaning and general stock maintenance, having received some advice from Dr John Hunt down in Exeter (a collaborator of my supervisor’s who also uses crickets and is an all-round awesome guy).
However, combined with my having somehow been coerced into giving a talk at the Scottish Ecological Ageing Group Meeting next week (I don’t work on ageing, so that should be interesting), this has been a pretty high-stress week for me as well. Thankfully, unlike the majority of my crickets, I’ve not yet been found curled up dead in a small piece of egg carton, but there’s always time.
I’m also due to go ahead with my interview for John Taylor’s ‘The Reptile Living Room‘ podcast this weekend, as part of his ‘Reptile Apartment‘ site, so that should be fun! Hopefully I shall remember not to swear, as my mum will tell me off if I do.