Costly colouration in a forest moth: the tale of a ten-year research project

As part of the Canadian Entomology Research roundup (the first two posts can be found here and here), we will be sharing more detailed posts from the grad students involved in the published research.

Below is a post from Jessica Ethier, sharing her research experience that spanned an undergraduate and PhD degree.


I just published a paper in Entomologia Experimentalis et Applicata. From start to finish, the work only took a decade.

Ten years ago, in the summer of 2005, I had just finished my first year as an undergraduate student at Concordia University. I had no plans yet for what I would do after graduating; really, I was just glad I’d survived that first year. But across the country, unbeknownst to me, traps were being set, insects were being collected, and by the time I was starting my second year of university here in Montreal, a student at the University of Alberta was busy pulling the wings off a bunch of dead moths.

A horrific sight to innocent insect passers-by.

A horrific sight to innocent insect passers-by.

That student was Kevin Lake. He was doing his undergraduate research project on the effects of population density on wing size and colour in the Malacosoma disstria moth with Maya Evenden and Brad Jones. Fast-forward one year to the fall semester of 2006, and I had now transformed (one might say, metamorphosed) into a seasoned third year undergrad dabbling in research for the very first time. In Emma Despland’s lab, I had a freezer-ful of more dead moths just waiting to be de-winged and studied, and (thanks to Maya and Emma) the protocols Kevin used for wing removal and colour scoring. One thing led to another, and before I knew it, it was 2009 and I had just fast-tracked to a PhD from a Master’s for my research on colour polymorphism and wing melanization in the M. disstria moth.

One of the aims of my graduate research as a whole was to try and figure out why there was always so much individual variation in colour within the genetically-based phenotypes. Emma and I developed an experiment for spring of 2010 to see if limiting dietary protein in the larval stage limited the expression of colour in the adult moth. I even had my very own undergraduate student for the project, Michael Gasse, to rear the insects, process the wings, and collect the colour data. But it wasn’t all rainbows and puppies and pulling wings off dead moths. First we had to get the insects from somewhere.

As luck would have it, there was a forest tent caterpillar outbreak about an hour away from the city that year (for some reason, the landowners – maple syrup producers – were not nearly as gleeful about this infestation of their sugar maple forests as all the members of the Despland lab were). So off we trooped in the middle of February, tree clippers, binoculars, and plastic lunchboxes in hand, to go collect as many egg masses as we could get our mitts on.

You thought the lunchboxes were for lunches? Photo by Alison Loader

You thought the lunchboxes were for lunches? Photo by Alison Loader

Then it was back to school, to spend most of April, May, and June in the sub-basement dungeon lab, slaves to the needs of the exponentially-growing, insatiable eating and pooping machines that we called our experimental subjects.

First instar M. disstria colonies in 30mL hatching cups with artificial diet. Those cups are basically the little plastic shot glasses you see at dollar stores. By the time they reach the final instar, the caterpillars are typically longer than those cups are tall. Photo by Alison Loader.

First instar M. disstria colonies in 30mL hatching cups with artificial diet. Those cups are basically the little plastic shot glasses you see at dollar stores. By the time they reach the final instar, the caterpillars are typically longer than those cups are tall. Photo by Alison Loader.

We all survived another research season, and Mike moved on to wing-pulling and colour scoring a few hundred moths. Time flew by, as time will do, but in 2012 I finally finished and submitted my article on nitrogen availability and wing melanization in the Malacosoma disstria moth!

It was rejected.

Undeterred, I chose another journal and submitted again. And again. And again. After the fourth or fifth rejection, I stopped resubmitting. Not because I was giving up, but because I had to write my thesis and graduate. Once that little matter was taken care of, I went back to my pesky paper. Looking at it with fresh eyes, I realized that the two sections I had divided my paper into just did not complement each other, despite being based on the same experiment. Then I had an epiphany. One of the reasons for forest tent caterpillars to suffer nitrogen limitation in real life is high population density.

And the rest, as they say, is history.

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