Gene expression analysis reveals a single origin for Nymphalid butterfly eyespots

This paper from Antonia Monteiro lab came up in my Reader feed the other day, and I was so impressed I thought it deserved a blog post. Here goes:

The paper applies two approaches to answering the question of whether eyespots have a single or multiple origin in Nymphalid butterflies, when this trait evolved, and to shed some light on the gene networks involved.

One approach was to plot the presence/absence of eyespots in 399 Nymphalid species (and 21 outgroup species ) onto a previous phylogeny. The distribution of the trait over the tree was used to fit alternative models of single, double or triple origins of the trait, using a Bayesian approach. The authors found that the most consistent model, given the data and the tree, was a single origin of eyespots at the base of the Nympahlidae.

In parallel, the expression data of 5 core developmental genes previously implicated in wing patterning - expression ofthe genes Antennapedia, spalt, engrailed, Distal-less and Notch in eyespot foci were analysed using antibody stains for23 Nymphalid species. The presence or absence of gene expression of each in presumptive eyspot foci was scored and the distribution of trait values across the phylogeny was analysed in a similar way to the presence/absence of eyespots. Their Figure 1 shows a single origin for co-expression of Notch, spalt and Distal-less at the base of the Nymphalidae, but the results for engrailed and Antp were ambigous (the association of these genes with eyespots might have evolved more than once).

The fact that 3 genes together are associated with eyespots at the base of the Nymphalidae is strongly indicative that the network for eyespot pattern was co-opted from a pre-existing role elsewhere in development, a fact re-inforced by the observation that the genes are expressed in a characteristic order (Figure 2):

All in all, this is a really interesting paper, and a brilliant demonstration that butterflies are a wonderful model system for examining the evolutionary and developmental biology of many complex (and visually striking) traits.

A desktop wiki instead of a linear logbook - my personal journey

Anyone who works with command line programs enough eventually realises the need to keep a log of their activities. It's not fun, but its much less painful having to go back to the manual every time you want to run something. Also, a log helps to keep track of the options and settings that were used.

Up until recently I did this linearly. I had a text document in which I would add a small heading and then the commands I used to do what I was doing. If I wanted to repeat a command used previously, but with slight modification, I would have to search the entire file for that command. This was OK at first, but eventually I had multiple versions of certain commands, each for a slightly different purpose, scattered throughout this file. I wanted to be able to keep commands for the same program together. But I also wanted to keep all the commands for a specific task together, even if that task involved several programs. This didn't seem feasible in the linear text file format, so I started to search for alternatives.

In general I decided that keeping a separate file or page for each task or program would be best. This could be done manually, using multiple text files, but this seemed cumbersome. I discovered that there were several free programs that offered this functionality. Most of these are designed for keeping track of ones thoughts, ideas, todo lists etc. Popular examples include Tomboy (simple and easy) and BasKet Note Pads (Complex and versatile). An additional function that these both have is the ability to create links. You can make links to other flies such as papers and manuals, links to websites and best of all, links to other pages. Rather than a single very long file, I could keep a network of inter-connected, smaller, pages.

Tomboy allows easy linking between notes

BasKet Note Pads allows you to make complex and beautiful pages

After extensive reading I decided to go with a less well-known "desktop wiki" program called Zim. A wiki is simply a website that allows users to edit pages - the best known example being wikipedia. Zim works like a website in that pages can be linked and organised in a heirarchical structure, but it isn't online, it's all saved locally. Creating links, formatting text and embedding images is really quick and easy. I have completly migrated to Zim, and so far it meets all my needs.

Zim's interface is simple yet powerful

At first the idea of a network of linked notes sounds more complicated than a single log file, but this change has definitley simplified my life, and I recommend it. Zim currently has linux and Unix versions, but I'm sure there are other programs out there with similar functions.

Fieldwork in South Africa - "coffee is coffee, tea is tea"

This is a quick post, on the urging of Simon, about a recent collecting trip to Limpopo province in South Africa. My co-conspirators for this trip were from the Brakefield lab in Cambridge: Erik van Bergen:

Erik with his first-ever wild-caught butterfly, a Papilio demodocus

and Oskar Brattstrom:

Oskar in typical pose and attire

The aim of our trip was to capture live females of Papilio dardanus (the  most interesting butterfly in the world), along with various Bicyclus species. The trip came out of a workshop held in Ghana on Afrotropical Lepidoptera research. There, Oskar and I met several extraordinarily interested members of the Lepidopterists' Society of Africa (seriously, go there and join), among them Bennie and Andre Coetzer who, after hearing about the butterfly projects in Cambridge (and over many beers) insisted that we visit them in South Africa and they would show us a site "where you could pick the butterflies off the trees with your fingers."

|Andre (far left) and Bennie (next to Andre) Coetzer in Ghana

After our return to Cambridge, it didn't take long to commence planning on the South Africa trip.

Upon arriving in Johannesburg, and picking up our loyal Josephine from Avis, we were treated to some incredibly warm hospitality from the Coetzer's, before striking out for Limpopo. After a braai (and a little too much fine Windhoek draft) at Nwanedi resort, it was time to get into the field! Our hosts had talked up Mphaphuli (our field site) quite a lot, but we were happy to see it didn't disappoint!

Aside from an absence of Bicyclus ena, all the other species we were hoping for were present in abundance, although, given the goals of Erik and I of establishing cultures of butterflies in the UK, there was a slight lack of females (in butterflies, it is usual to observe an excess of males in the field, given the shy and cautious behaviour of female butterflies). Oskar, seeking only pheromone samples, completed his fieldwork rapidly. 

Keeping the butterflies alive in our accommodation proved to be a little trickier, however. I settled on a regimen of twice-a-day feeding of all captive swallowtails, and leaving them in cages at the field site wherever possible. Despite the high mortality of captured swallowtails (not that surprising given their short life expectancy as adults), I was able to get many many eggs by putting cages with mated females onto host plants.

Quenching the thirst of butterflies and scientists alike

Hand-pairing of Papilio dardanus

Mphaphuli proved so productive that we were able to give ourselves a day to see some other zoology in the Kruger National Park:

Oskar's camera is way better than mine

Too too funny to not include.

After packing up and heading home, it did indeed prove possible to get some livestock established in the UK. I'll try and persuade Erik to write something about the Bicyclus, but from my point of view, although only a minority of the eggs I had hatched, enough larvae have survived to do some crosses and I have eggs again (one generation out from the wild)!

The only minor downside from the trip was that one day after returning to the UK, I started to develop symptoms of African tick-bite fever. 

In conclusion, the trip was a roaring success and I owe a great deal of thanks to Oskar, Erik, LepSoc Africa and the Coetzer family.

"I hate my job"