It has been quite some time since I posted anything on my blog, but rather than providing a long whinge about why this is so (and because ‘I’ve been busy’ doesn’t really cut it at any stage once you’ve decided to plough into the academic lifestyle), I thought I would use the experience of the last couple of months to give some handy hints to other students on a topic I have good experience of: surviving long, complicated, tedious, lonely lab experiments. As in, 8-13 hours per day, every single day of the week, for several months, in a small room by yourself, kind of experiments. The real glamour of PhD life.

1) Let yourself go

Me in my dungeon

Because nothing tells your colleagues that you’re working hard like a terrible beard (not sure what the female equivalent is, I’m afraid), and the red eyes that indicate a person running on caffeine fumes. Over the last couple of months, I’ve lost over 6kg accidentally, purely from being too busy to eat lunch. Not that I’m asking for sympathy, because I’d got a bit fat beforehand – this just means I don’t have to start running again. SCORE.

2) Give your ears a treat

Your hands and eyes may be focused on some monotonous task – like, say, putting tiny food dishes into many boxes which each hold a single insect, just as an example I made up for no reason at all – but your ears are still free to feast upon the glorious smorgasbord that is the collected works of human endeavour (or something). You can raid iTunes U for lecture series, catch up on your favourite podcasts (and a bunch that you don’t really like, but you’re so tired that you can’t bring yourself to search for better ones), or – and this has revolutionised my recent listening – sign up for an Audible audiobook account. If you’re going to be stuck in a lab by yourself for hours on end, you can even get through audiobooks that you would otherwise baulk at, which is how I managed to power through all 57 glorious hours of the unabridged version of David Foster Wallace’s ‘Infinite Jest’.

Podcasts I like:
Little Atoms (be sure to get the ‘Little Atoms Road Trip’ podcasts as well)
Quirks & Quarks
The Life Scientific
Breaking Bio (*cough*)

Audiobooks I enjoyed:
‘Infinite Jest’ by David Foster Wallace
‘The Greatest Show on Earth’ by Richard Dawkins
‘Snow Crash’ by Neal Stephenson
‘Life on Air’ by David Attenborough
‘The Human Stain’ by Philip Roth
…also, ‘How to be a Woman’ by Caitlin Moran, although this is not necessarily the wisest choice when spending many hours in the dark, by yourself, and feeling a bit confused about everything in general.

3) Take your birding when you can get it

Birds are great, and if you don’t think so then YOU ARE DEAD INSIDE. I filmed this from the lab window, having spotted this dust-up on a short break from my sealed-off dungeon to weigh a bunch of crickets (the only lab scales are upstairs). I really need to thank the guys in the BTO office down the hall for having put a bird feeder outside…

4) Walk to work

This enables you to get the bare minimum of sunlight and fresh air that you probably need, and also stops your muscles from completely atrophying. Hopefully.

It also helps if your ‘commute’ looks like mine.

Just some hares and some deer hanging out in front of the Ochils. No big deal.

5) Take your animal behaviour when you can get it

We all like watching animals do stuff, right?

Even if you’re restricted to just watching your study organism over and over again, it still counts.

6) Pretend everything is fine

I don’t want to get all ‘the power of positive thinking’ or any bullcrap like that, but there’s a lot to be said for just deciding not to be in a huff when you get home from 13 hours slogging away in the lab and not having spoken to anyone all day. If you have a partner, they’ll certainly thank you for it. Or at least be less likely to break up with you because you are being massively insufferable.

7) Arrange something at the end to look forward to

I’m getting married, but maybe you don’t want to plan for that every time you start designing a long experiment. We are then going to Borneo for three weeks as well. You probably can’t plan for that either, but at this point, I don’t care about you. I don’t care about any of you. I just care about MY DATA.

Oh, and try not to think about the fact that you’ll probably spend the next 6 months trying to do statistical analysis and work out what any of it means. HAHAHAHAHAHAHAWHYYYYYYYY

But I have a secret weakness, and that weakness is for otters. Now there is an otter living in the river outside my flat.

Just look at this guy.

Enjoying a little swim in the snow.

After it bounded past the tree, it just rolled about in the snow for a while, having an awesome time.

At least I have a trump card to play when it comes time to put the flat on the market…

OH GOD I LOVE OTTERS

Let us never speak of this again.

*Of course, Katie is actually awesome. Just check out this video of her ‘Harvard Thinks Big’ talk.

Ah, the humble flower. Often surrounded by kin, allies and potential partners, yet always somehow alone. Straining in the wind for a gentle touch, the slightest caress, yet all around surge away as one. What happens when, every time you reach out, all others move aside? Do you dare to hope, to dream, that there is another flower out there, one just like you, one with which to share your thoughts and dreams and aspirations and, most importantly, your gametes?

Just as a shy teenager, crippled by insecurity, might ask a friend to pass a message on to the object of their desire in a school classroom, so plants may harness the power of proxy. Insect pollinators, buzzing from flower to flower with a gametic note attached, are often bribed with food rewards of nectar or pollen as part of this sexy bargain. However, in another parallel with some sullen human adolescents, orchids despise such brazen capitalist tendencies.

Instead, they lure these pollinators, their little sex proxies, with sweetly perfumed and brightly coloured promises of food, promises they will never come good on. But this is not deception enough for some orchids, no. In a cruel twist, they can actually mimic the sex pheromones of the female of a particular insect species, driving the males wild with lust. The orchid’s labellum even imitates the look of the seductive female, tempting the male over to attempt copulation. And as he does so, grinding away in an ultimately fruitless pseudocopulatory frenzy, the orchid gently attaches some pollen to him, to be passed on to the next player in this nefarious reproductive game.

The image above shows the wasp Neozeleboria cryptoides attempting copulation with the “bird orchid”, Chiloglottis valida. The flower mimics the sex pheromone of a female wasp so precisely that the male cannot distinguish between the mimic and the real deal. In one genus of Australian orchids (Cryptostylis), the wasp can even be provoked into ejaculating with the orchid.

You may say to yourself, why sully yourself in such a manner? Why not just pay for this service? And isn’t allowing a wasp to engage in intercourse with you to the point of ejaculation akin to a warped form of bestiality?

To which the orchid would sigh, close its black moleskine notebook, and gaze up at the Che Guevara poster on its wall. Don’t push your human morality on me, man, it says. You just wouldn’t understand.

More information on orchid pollination can be found here.

The original image was provided by and is the copyright of Mike Whitehead, who studied this system in Australia for his PhD, and from whom I first learned all about this weird shit when we met at ESEB 2011. You can follow him on Twitter, and also be sure to check out some more of his excellent photographs of this particular species in action.

This was originally posted on my other website, NatureSexTopTips, which is no longer active.

In 2012, I’ve been lucky enough to travel around Scotland a fair amount, and got a few nature firsts here – crossbills, vivaparous lizards, and finally saw the magnificent capercaillie (and ran away from it as it chased me and a very famous evolutionary biology professor up a path!). I also went to Sweden for a quantitative genetics workshop (where I learnt to love long johns as much as matrix algebra), took a trip to Canada (where I gave my first talk at a major international conference, Evolution 2012), and holidayed in Barbados (where Kirsty and I celebrated our engagement). The final bonus photo in this gallery is actually from 2013, and I hope it is a portent of good things to come!

I’m going to post this to Alex Wild’s request for end-of-year photo sets as well; mine certainly won’t compete with most of those on show, so you should go and check them out! There is some RIDICULOUS stuff going on. Hopefully I’ll have a competitive selection next year, as I’m off to Borneo in July for my honeymoon! That’s right: I’m getting married, like a real grown-up person.

Note: I’ve noticed that various people have ended up here after searching for rogue capercaillie in Speyside… I can’t give out the location myself, but I will say that we were taken there by a local wildlife guide, Steve Reddick, who was an excellent host and whose rates are also extremely reasonable!

That’s correct, friends – the two beetles you see in this image are both adult males of the same species of dung beetle, Onthophagus nigriventis. The chap on the right is clearly larger, and has a rather ostentatious horn extending from his thorax. This horn is a sexually-selected trait: horned males can use their armaments in battles over females, driving rivals away from mating sites, and even prying other males off a female whilst in flagrante. Sexual selection is all about the struggle to reproduce, and so traits are ‘sexually selected’ if their expression confers some benefit to the holder in terms of reproduction. In this case, large males with large horns are more likely to win battles with rivals, enabling them greater access to females, so there is a clear advantage to investing resources into weapons development.

Given that big, horned males fight rivals and guard their female partners (they may engage in the rather ungentlemanly pursuit of trapping lady beetles in mating burrows in order to have their way with them), then what the crap is going on with the guy on the left? Well, these horns are likely expensive in terms of resources, and any energy ploughed into growing horns is not available for investing in other traits – indeed, horns are known to trade off against morphological structures including eyes, antennae, and wings. Species of Onthophagus are well known for the size and diversity of their horns, but often these are only expressed by the largest ‘major’ males. What happens, then, if you’re a down-on-your-luck, resource-starved ‘minor’ male? Is there really any point in cashing in your precious metabolic chips for a gamble on a crappy little horn that’s never going to help you win any contests anyway? Surely there’s another strategy to be taken?

Indeed there is, and it’s called being a ‘sneaky fucker’*. While some males guard their mates, others will try to ‘sneak’ copulations with females. We now enter the realm of sperm competition: females may mate with multiple partners, so there is a battle amongst the sperm within her reproductive tract to fertilise eggs. If ejaculates are costly, males have to trade off resource investment on gaining fertilisation with investment on gaining additional matings. The more sperm ejaculated in a mating, the more eggs are likely to be fertilised – but, again, this requires resource investment. Furthermore, an increased risk of sperm competition should favour the evolution of increased expenditure on the ejaculate (i.e., the more likely that your little swimmers are going to be racing against some other dude’s, the more investment you should be making in ensuring your ejaculate is the biggest and best it can be).

In plain English (or, at least, an approximation thereof): if you’re a big horned dude protecting a little beetle harem, then you shouldn’t be all that worried about the fertilisation aspect – after all, you should be the only one for your ladies. You want to invest in lots of mating, not lots of ejaculate. Meanwhile, as a sneak, you’ve got to make those precious moments count, and ploughing your resources into the ejaculation makes sense – it’s in the female’s interests to have a few flings behind the dung-balls, so the greater the ejaculate, the better your chances of gaining fertilisations. Of course, the best way to produce larger amounts of ejaculate is to invest more resources into testis development.

All of which leads us nicely to what I think is one of the most ingenious (albeit slightly harrowing, once you really think about it) experiments I’ve read about while studying up for my PhD. Leigh Simmons and Doug Emlen (yes, this is another Doug Emlen-related post) cauterised those cells on beetle larvae which produce the thoracic horns in O. nigriventis, manipulating investment by ensuring that they could not grow these weapons. When compared to a control group comprising beetles allowed to develop normally, the cauterised individuals not only grew larger in size, but also developed disproportionately large testes. These results revealed the metabolic trade-off between horn development and both body size and testis size, in line with predictions from evolutionary models of ejaculate expenditure.

But what does this mean for the two beetles at the top of the page? Well, there’s a general tip here: if you’re going to sneak around, you’d better have gigantic balls.

*I’ve been told that Geoff Parker coined this phrase, but have been unable to find a reference for this, and during googling I accidentally clicked on ‘images’ and.. yeah. I need to keep safe-search on in future.

This post is a slightly modified version of an earlier entry on my ‘Nature!Sex!TopTips!‘ website.

Research blogging reference:

Simmons, L., & Emlen, D. (2006). From the Cover: Evolutionary trade-off between weapons and testes Proceedings of the National Academy of Sciences, 103 (44), 16346-16351 DOI: 10.1073/pnas.0603474103

Other references and further reading:

Simmons LW, Emlen DJ and Tomkins JL (2007) Sperm competition games between sneaks and guards: a comparative analysis using dimorphic male beetles. Evolution 61(11): 2684– 2692.

Emlen DJ (2008) The evolution of animal weapons. Annual Review of Ecology Evolution and Systematics 39: 387–413.

Parker GA (1990) Sperm competition games – sneaks and extra-pair copulations. Proceedings of the Royal Society of London Series B – Biological Sciences 242(1304): 127–133.

Blatant plug: I am really interested in the intersection between sexual selection and life-history allocation – the way that individuals invest their resources – and (along with my long-suffering supervisor) have written an article on this topic for Wiley-Blackwell’s Encyclopedia of Life Sciences online journal. You can find it at the following link, or drop me a line if you would like a copy:

Houslay TM, Bussiere LF. 2012. Sexual Selection and Life History Allocation. In: eLS 2012, John Wiley & Sons, Ltd: Chichester.

The original image is the copyright of Alexander Wild, an entomologist, photographer, and all-round great guy. You can find the original, and more of Alex’s work, at the links below:

http://www.alexanderwild.com/

http://myrmecos.net/

http://blogs.scientificamerican.com/compound-eye/

https://twitter.com/#!/myrmecos

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STABBYCOCKDAGGER

Due to reasons too numerous and boring to go into, I have decided to delete this post. My apologies to anyone disappointed by this!

If you want to read something else I have written, why not try this post on beetle sex: ‘horny decisions, sneaky f**kers, and the importance of balls‘?

If, however, you’re set on some stabbycockdagger action, then head on over to the Breaking Bio website to find some of our podcasts…  Episode 10 features Nik Tatarnic talking about traumatic insemination in plant bugs, while Episode 11 is an interview with Prof Mike Siva-Jothy, whose research involves work on some very stabby bedbugs. You can also get the Breaking Bio podcasts on iTunes.

I should probably mention that the blog post in question was actually a rather sober discussion of science journalism and sensationalism in the mainstream media, but hopefully the previous paragraph and accompanying picture will have done the desired damage to Steven’s reputation.

The podcast itself is a light-hearted chat between a bunch of nerds about various topics: recent discoveries, big topics in the scientific community, conferences, weird insect genitalia…   all of the things you’d expect, and maybe more (especially when Bug Girl is around!)

We are about 6 episodes in just now, so there’s plenty for you to catch up on – there’s also something of a rotating cast of characters to get acquainted with:

Steven Hamblin – yeah, the dolphin rape guy in the underpants. Not only does Steven have to try and figure out times for various people across the globe to chat for an hour or so once a week, he also has the job of keeping us on a vague topic, and the frankly horrendous task of editing it all into something coherent afterwards. Oh, and he’s a postdoc in Australia doing extremely hard maths about zombie caterpillars.

Morgan Jackson – entomology PhD student at Guelph, awesome photographer, and fly lover. But not like Steven is a dolphin lover. This is a purer love.

Rafael Maia – a PhD student at the University of Akron, Rafael does some unbelievably cool work on the evolution of bird feather colouration. He’s also, like, Mexican or something. I dunno.

Bug Girl – with a PhD in entomology and a reluctance to reveal her true name, Bug Girl is something of an enigma. She’s like a superhero, albeit one whose superpower is talking non-stop about insect genitalia and how Spiderman should really spooge web out of his butt and suchlike. Basically, she’s fucking brilliant.

Crystal Ernst – another entomology PhD student and awesome photographer, Crystal also blogs as ‘The Bug Geek’, no doubt invoking her own ire as she struggles to contain her geekiness solely to the order Hemiptera.

Michael Hawkes – unfortunately, Michael is doing a PhD in something which can be described as ‘applied’, seeing as it might be of practical use one day, so I’ll be damned if I’m going to lower myself to writing about it here. He’s at the University of Exeter. He also MAKES ME SICK.

We’re also hoping to extend this list to a few more characters, with hyper-enthusiastic science goblin Lauren Reid lined up to join us in future, the fabulous Bug Chicks stopping by, and PROPER GROWN-UP REAL SCIENTIST GUY Rob Brooks having been cajoled into making a guest appearance. Rob shall likely be discussing his book, ‘Sex, Genes, and Rock & Roll‘. Hopefully we can also get him to respond to what is probably my favourite ever online comment, left underneath his article on cats and toxoplasmosis:

…but perhaps his cameo appearance on the podcast will make him feel better? Either that, or we’ll send him spiralling further down into a pit of despair.

But where can I watch this awesome sounding podcast?, you may be wailing at this point, anguished by my inability to write a short blog post that gets to the point within a reasonable number of characters, why dost thou maketh me wait like some putrid syphilis-riddled chump, you cry, suddenly resorting to ye olde English like creationists do when you’ve argued them down and they’re trying to regain the upper hand through patronising misquotations of not-particularly-relevant bible verses.

WELL

Subscribe via iTunes

Watch the videos on YouTube

Follow @BreakingBio on Twitter for updates

Thankfully, a bunch of your favourite tweeters/tweeps/tweehavioural ecologists (delete as appropriate, especially the last one) are keeping the rest of us in the loop; you can follow the stories as they come by using the #ISBE2012 hashtag. This is a great way to keep up with current and emerging research, as well as just finding out about cool stuff! Here are some highlights:

I urge you all to go and check out the full stream of #ISBE2012 tweets coming from this dedicated bunch of very excited academics – I recommend you follow them all anyway! If you want to find out more about any of the talks, you can look up the speakers on the conference programme. It’s so fantastic and exciting that we have the technology that enables those of us who can’t make these events to keep up with what’s happening, and feel as though we are still a part of it…

It makes me a bit sick when I think about how awesome this lab is.

I have a real soft spot for research on beetle horns, as followers of Nature!Sex!TopTips! may be aware, so I was really excited to see Emlen’s talk – even more so after the taster that was Erin McCullough’s presentation earlier in the week (McCullough is a PhD student co-supervised by Emlen and Bret Tobalske at the University of Montana’s ‘Flight Lab’). Research into animal weaponry often goes hand-in-hand with studies of ornaments because there is direct sexual selection upon them; females use ornaments as a basis on which to select a mate, while weapons are used by males to defeat rivals (or to assess their condition and status) and so gain access to females. Together, these exaggerated, elaborate structures are some of the most incredible sights we see in nature.

The rhinoceros beetle Trypoxylus dichotomus, used in both Erin McCullough’s work on how horn size affects flight and Doug Emlen’s research into the mechanistic basis of exaggerated trait expression. Photo copyright flickr user Mushimizu (note: open the link from this image in a new window to see the animated gif in action!)

It’s no surprise that a lot of research investigates these amazing traits, but there are still some big questions to grapple with. For example, they seem to be very reliable indicators of male quality – why should this be so? Can’t some males ‘cheat’ by somehow investing more into ornament or weapon growth than other things? Also, if females select upon a particular heritable trait, then shouldn’t we see very little variation by now, with all males having pretty much the same size of trait? Consider the range of deer antler size in comparison to, say, the range of deer leg length. Antlers are much, much more variable – but why?

Brief non-beetle interlude: red deer, showing the variability in antler size and shape. Image copyright David J Slater.

I’ve written about the maintenance of genetic variation in such traits before, both here and over at the Nothing in Biology Makes Sense blog, using the ‘genic capture’ model proposed by Rowe and Houle. This model posits that the continued evolution of sexually selected ornaments and weapons is enabled by these traits ‘capturing’ the underlying condition of the animals. An individual’s condition is affected by its general health, nutrition, parasite resistance, competitive ability, etc…  essentially, the genetic variation among males in terms of all these factors underlies the variation in these amazing traits. It’s this ‘condition-dependence’ of traits, a close association with the individual’s condition, which means that the expression level should be ‘unfakeable’ and thus a reliable indicator of male quality. Not only this, but it also allows the evolution of ever-more exaggerated ornaments and armaments. So, these traits have some particular characteristics which have triggered huge interest from an evolutionary point of view: extreme size, heightened sensitivity to condition, and much more variability than we see in other morphological traits. We often think of condition-dependence as a kind of ‘black box’ – environmental and genetic factors go in, and traits come out. Emlen’s current research asks the question of, well, what mechanism enables this to happen? What’s inside the black box that creates these incredible, extreme biological structures?

Emlen proposes that there is a developmental explanation for this, and it lies within the insulin / insulin-like growth factor (IGF) pathway. This pathway has emerged as the central mechanism in animals for integrating physiological condition with growth; insulin and IGFs not only regulate tissue growth and body size, but they are also sensitive to factors such as nutrition, stress and infection. The levels of insulin / IGF circulating in an individual would cause a graded response via this particular pathway, with growth speeding up or slowing down in response to changes in nutritional or physiological state - i.e., the same kind of factors which affect what we term ‘condition’. So far, so straightforward, you might think: there’s a pathway which controls tissue growth that depends on how healthy and well-nourished you are. But how might this lead to the evolution of highly exaggerated weapons and ornaments?

Well, here comes the even cooler bit: traits differ in how they respond to these signals. This can have a truly profound effect on the amount and nature of their growth. Some traits, like Drosophila genitalia size, are not particularly sensitive to insulin / IGF signalling, meaning that they tend to be around the same size in all individuals, no matter their nutritional state. Wings, meanwhile, are more sensitive to these signals. Within a variable population of fruit flies, with a normal range of body sizes, we would see variation in wing size approximately equal to variation in body size, while genitalia size would hardly vary at all. So, just as wings are more sensitive to insulin signalling in Drosophila than are genitals, Emlen predicted that exaggerated weapons or ornaments are even more sensitive than that. Such heightened sensitivity to insulin / IGF levels would explain how such traits grow to extreme sizes, why there is such huge variation within populations, and why such traits seem to be reliable indicators of underlying quality.

Normal beetle service has resumed: the male rhinoceros beetle Trypoxylus dichotomus. Image copyright flickr user golbenge.

Emlen and his colleagues tested this hypothesis in male rhinoceros beetles (Trypoxylus dichotomus), which have a large forked horn on the top of their head. They used RNA interference (RNAi) to perturb transcription of the insulin receptor (InR) - that is, they simply stopped this particular signalling pathway from working properly. They did this at the beginning of metamorphosis, a point when body size is no longer growing, but adult structures – such as genitalia, wings, and the huge sexually-selected horn – are. If increased cellular sensitivity to insulin / IGF signalling is at least partly responsible for the evolution of this exaggerated horn in these beetles, then horns should be more sensitive than wings to the experimental manipulation of the pathway activity via RNAi. Furthermore, Emlen and his team predicted that – just as with fruit flies – genitalia should be relatively insensitive to this disruption of insulin / IGF signalling.

Results showed that the genitalia of males whose InR pathway activity was disrupted did not show a significant reduction in size when compared to control males (which did not undergo the RNA interference treatment). Meanwhile, the wings of RNAi treatment males showed a significant reduction in size that measured around 2% in comparison to control males. This is typical of the majority of ‘metric’ traits, such as eyes, legs, etc. Horns, however, predicted to be the most sensitive to nutritional state, suffered a significant reduction of around 16% in RNAi treated males relative to control animals. This eight-fold increase in sensitivity of horns in comparison to wings is highly consistent with Emlen’s model of the evolution of exaggerated trait size from heightened sensitivity to this particular pathway – giving us a real insight into the black box of condition-dependence, and how such incredible traits evolved.

Note: I highly recommend reading the paper itself, not only because it’s very well-written, but also because Emlen does a great job of summarising models of sexual selection and condition-dependent traits, and the impact of this latest research on those models. Plus there’s some nice beetle pictures in there, and you love nice beetle pictures. DON’T YOU?

Read the Science paper here:

Emlen, D.J., Warren, I. A., Johns, A., Dworkin, I. and Corley-Lavine, L. (2012) A mechanism of extreme growth and reliable signaling in sexually selected ornaments and weapons. Science (in press).

Other references:

Rowe, L., & Houle, D. (1996). The lek paradox and the capture of genetic variance by condition dependent traits. Proc. Royal Soc. B, 263 (1375), 1415-1421.

Shingleton, A.W., Das, J., Vinicius, L. and Stern, D.L. (2005) The temporal requirements for insulin signaling during development in Drosophila. PLoS Biol. 3, e289.

Further reading:

Cotton, S., Fowler, K., Pomiankowski, A. (2004) Do sexual ornaments demonstrate heightened condition-dependent expression as predicted by the handicap hypothesis? Proc. Biol. Sci. 271, 771.

Emlen, D.J. (2008) The evolution of animal weapons. Annual Review of Ecology Evolution and Systematics 39: 387–413.

Houslay, T.M., Bussiere, L.F. (2012) Sexual Selection and Life History Allocation. In: eLS 2012, John Wiley & Sons, Ltd: Chichester.

Shingleton, A.W., Frankino, W.A., Flatt, T., Nijhout, T.H., Emlen, D.J. (2007) Size and shape: The developmental regulation of static allometry in insects. Bioessays 29, 536.

That’s right, I did just recommend a review paper that I wrote. You should know by now that I’m absolutely shameless.

Here are some more notes on talks that I enjoyed at Evolution Ottawa 2012, with links to finding out more if you are so inclined…

Emilie Snell-Rood - Changing nutrient dynamics and the relaxation of sexual selection: effects of human-altered nitrogen inputs on butterfly mate choice

Image copyright Emilie Snell-Rood

I was really blown away by Snell-Rood’s talk, and a look at her research interests on her lab page shows that she’s working on some really interesting stuff and with very cool systems (including Onthophagus nigriventis, which have a very cool male dimorphism, work on which I wrote about previously on Nature!Sex!TopTips!). This talk looked at how the increased availability of a once-limited nutrient was affecting mate choice, using the cabbage white butterfly Pieris rapae. I’ve written in greater detail before on how variation in resource acquisition is important for the maintenance of genetic variation in sexually-selected ornaments, and it turns out that the acquisition and processing of nitrogen, a once-scarce resource, is important for the P. rapae male’s secondary sexual trait (ultraviolet signalling). Since around the end of World War II, fertiliser use in the USA has skyrocketed, flooding the system with nitrogen; Snell-Rood and her lab were interested in whether P. rapae ornamentation has lost ‘condition-dependence’ over time, given that this important resource is now widely available to all individuals?

One of the ways which we can use to figure out if a signal is condition-dependent is to look at allometry, or the scaling relationship between two traits (for more detail, see this great article by Alexander Shingleton, or this rather more in-depth paper by Russell Bonduriansky). A typical study would be to plot the trait of interest against body size; on the log-log scale, we’d expect a standard trait to have a slope of 1, so it is always in proportion to body size. Condition-dependence is a special type of plasticity, however, meaning that those in higher condition can afford the costs of increased investment in such traits. We’d therefore expect to see a slope greater than 1, i.e., larger individuals have proportionally larger traits. This is called positive allometry. Using museum specimens and previously collected data (if my memory serves me correctly), Snell-Rood found that after WWII – and thus after the environment became flooded with high levels of nitrogen – these butterflies no longer exhibited a greater body size : ornament correlation. This is a really neat study, and I’m very excited to read the paper when it arrives – Snell-Rood also mentioned a few other experiment underway in her lab that sound very cool, using irradiated fathers (so likely more deleterious mutations) and differing levels of nitrogen to investigate ornamentation and female choice. This is extremely awesome! Until then, you’ll have to make do with this interesting review she wrote recently on adaptive phenotypic plasticity…

Devin Arbuthnott - Ecology and sexual conflict in Drosophila melanogaster

This talk centred around the idea that sexual conflict and ecology may not be as separate as one might think, and that adaptation to different environments may promote parallel changes in sexual conflict and population interactions. I don’t have much in the way of notes from this talk, but Arbuthnott is working on some very cool stuff, and published a paper in Evolution recently with Howard Rundle that has some very interesting implications: ‘Sexual selection is ineffectual or inhibits the purging of deleterious mutations in Drosophila melanogaster‘.

Christopher Chandler - Runaway sexual selection leads to good genes

Chandler presented some work on how runaway sexual selection and good genes are not mutually exclusive, using the ‘Avida‘ platform. This is a computational system which uses self-replicating digital organisms to investigate questions that we can’t address with natural organisms. As someone with a computing background, I’m really interested to see whether this type of work gains more acceptance in the mainstream literature. Avida is currently used in the ‘DevoLab‘ for teaching evolution at Michigan State University; the 2004 Ofria & Wilkes paper describing the system can be found here.

Erin McCullough - Elaborate weapons: the costs of producing and carrying horns in a giant rhinoceros beetle

I’ll be honest: I pretty much just went to this talk as, after a couple of theory-heavy talks, I wanted to see some cool pictures of giant horned beetles. McCullough didn’t disappoint in that regard, but also presented some very cool work that also seems to challenge our ideas of the costs involved in the carrying and production of oversized secondary sexual characters. She found that, in the species Trypoxylus dichotomus, horns are not costly in terms of body mass as they are hollow and air-filled. McCullough is interested in how such horns affect flying, which is important for mate-searching, and found that any issues in regards to drag are more likely due to body angle than horn size, with horns really having only a trivial effect on flight. She found no evidence for allocation trade-offs, merely some evidence for compensation in terms of male flight apparatus (but not, for example, changes in muscle mass). McCullough’s recent paper in Behavioural Ecology discusses whether horns were costly in the past, and how this may have led to compensatory changes in terms of wing and muscle morphology. I’m excited to see what further research tells us about the evolution of horns in this particular species.

That’s all for now, but plenty more to come…