Can  you add this to the publication list, please:

2010. Salcedo, C. Environmental elements involved in communal roosting in Heliconius butterflies (Lepidoptera: Nymphalidae). Environ Entomol. 39(3): 907-11.

2010. Salcedo, C. Evidence of pollen digestion at nocturnal aggregations of Heliconius sara in Costa Rica (Lepidoptera: Nymphalidae). Tropical Lepidoptera. 20 (1): 35-37.

Saludos,

Christian

Evolving wings
The Edmonton meeting was no exception to the rule, and there was a generous helping of Heliconius biology to boot. Much of this revolved around wing pattern genetics, with ongoing efforts to identify the genes that control wing patterns finally starting to come to fruition after some ten years of effort in labs on several continents. Perhaps most exciting, the identification of striking expression patterns at a transcription factor previously associated with eye development, by Arnaud Martin and Riccardo Papa, appear to signal the identification of the loci controlling red pattern elements in both Heliconius erato and melpomene. Similarly, Marcus Kronforst has now identified a regulatory gene (transcription factor) that controls the switch between yellow and white in the Heliconius cydno group, while Nicola Nadeau presented data for a cell cycle regulator that is prime candidate for the switching of yellow patterns in Heliconius melpomene.

For me, the identification of these genes has been something of an obsession over the past few years and it is a relief that we are finally close to an answer. The results seem to confirm the hunch that we have had for a while now, that the same genes are involved in producing similar patterns across many Heliconius species. There really is a common ‘toolkit’ of wing patterning genes that are shared across many species. What is surprising is that the genes identified so far do not seem to obviously fall into a single signalling pathway, or interacting network. The challenge now is to figure out how they have evolved to produce the remarkable patterns of Heliconius from their fritillary ancestors, and whether there is something specific to the way patterns are generated that allows such remarkable diversity to be produced in Heliconius.

There was another surprising result presented at the meeting, from linkage mapping projects in Bicyclus (a satyrid or brown butterfly) and the peppered moth. In both species, genes affecting wing patterns (eyespots and melanic wing colouration respectively) map to the same regions of the genome as one of the Heliconius wing patterning genes that was first mapped in our lab. If it really turns out that the same genes are involved in these species, this would imply that there is a shared mechanism for wing evolution across moths and butterflies, which dates back to the time of the dinosaurs. Now that is pretty cool.

Hissing peacocks and new dimensions to communication
One of the most surprising talks for me was a tale of hissing peacocks and mice. Peacock butterflies are known for the stunning eyespots on their wings, which are used to startle predators when they are approached. What is less well known, is that they also make a hissing sound with their wings. This proves remarkably effective at deterring mice, that would otherwise make a meal of them during hibernation. Videos of hibernating butterflies presented by Martin Olofsson showed mice approaching sleeping butterflies, and being startled off by wing flaps, in the complete darkness of a winter roost. It seems that the startle display of the stunning peacock eyespots is complemented by an equally scary audible signal generating by rubbing the wings together. Heliconius cydno are also supposed to make clicking noises (although I have never heard them myself) – perhaps they serve a similar function.

While sounds may be important for some butterflies, a far more ubiquitous mode of communication is through scents. However this remains a black box of butterfly biology, which is only just beginning to be opened. Fritz Muller (famous for the discovery of Mullerian mimicry), was the first to described the feathery ‘androconial’ scales on butterfly wings that diffuse their scents, in the 1860s. In Edmonton, Carla Penz and Naomi Pierce, discussing owl butterflies and blues respectively, both described remarkable patterns of diversity in the placement, shape and form of these androconial patches on the wings. Such rapid evolution generally signals strong selection, and in this case it is likely driven by sexual selection. This was confirmed by Caroline Nieberding, who has identified the compounds that the African butterfly, Bicyclus anynana, uses for sex. The females of this species choose to mate with males based in part on their chemical bouquet, with the older males having a distinct smell that is preferred by females. This makes sense, as older males have survived the trials of life on the African savannah and are therefore more likely to have successful combinations of genes that will produce fit caterpillars. However, the puzzle is why males don’t cheat the system and pretend to be older than they really are by producing the characteristic chemical signal. Perhaps the signals are expensive or difficult to produce, but there is clearly potential for conflict between the sexes in the use of these chemical signals that could lead to an evolutionary arms race and perhaps explain the rapid evolution of the androconial patches and their chemical bouquet.

In Heliconius, a poster by Catalina Estrada described a different set of chemicals known as anti-aphrodisiac pheromones. These have the opposite effect to the Bicyclus sex phermones, and as their name suggests deter mating by males. The chemicals are transferred from males to females at mating, and presumably serve the interests of females who benefit by avoiding pestering by ardent suitors (although such a benefit has yet to be demonstrated). Strikingly there is also a similar pattern of rapid evolution in these chemicals, with closely related species commonly differing in their chemical composition. Catalina has demonstrated that species in the pupal-mating clade evolve more slowly than the non-pupal-maters. This also fits with the idea that conflict could lead to rapid evolution, as among pupal-maters the males call the shots and there is little opportunity for females to choose their partners, while in non-pupal-maters both species can choose so there is more chance for them to differ in opinion – hence more conflict. Once again, sexual conflict is associated with faster evolution of chemical signals.

Researchers are just beginning to explore the world of butterfly scents, and this is clearly an exciting area for future research. No doubt ‘Biology of Butterflies’ in 2014 will have more on this topic…

And more…
Overall the meeting included many more aspects of butterfly biology than I can even begin to mention here. Butterflies continue to be at the forefront of our understanding of the biological response to climate change, with striking range changes very evident at both the warm and cold fringes of species ranges. However, at this meeting there was a shift in emphasis away from simply documenting range changes in response to climate, towards investigating how we might best respond to such changes. Other talks covered so many aspects of butterfly ecology, population biology and evolution that I was exhausted by the end of the week. To recover, we headed south to the Alberta prairies and Drumheller, for some dinosaur therapy.

Heliconius doris eggs and larvae decimating a Passiflora in the Kaw Mountains of French Guiana.

An erato pupating

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Many thanks to Kate Raisz and the 42 Degrees North film company who supplied this clip. And thanks Owen for pointing out the correct accreditation.

Over the two days, Heliconius biologists, bioinformaticians, others from sequencing centers and places of the sort, developed a timeline and framework for annotating, curating, sharing and analyzing the H. melpomene genome. The first freeze and release of an assembled H. melpomene genome could be within the next 3 months. Servers at UCI are already in place in order to hold the sequence data, a BLAST server and a GBROWSE server. Over the coming months CHADO databases will be built, annotation pipelines will be laid, and preliminary genomic analyses will begin.

Beyond the first H. melpomene reference genome being done with 454, we have had our eyes on other races and species of Heliconius to sequence. Plans were outlined for re-sequencing the genomes H. cydno, H. numata, H. erato and more H. melpomene races using Illumina. Plans were also made for RAD-tagging, using Illumina. Mapping families are currently being raised in Panama to create a RAD-tag linkage map for the H. meplomene genome. We are also considering using RAD-tags to scan for population differentiation between the various races of H. erato and H. melpomene. At this point the genome project seemed to be expanding significantly, but the biology was getting a lot more interesting. We just need to convince some funding agencies.

The meeting slowed to a discussion of funds, and how to afford all these awesome experiments. Grant opportunities were discussed and working groups on various topics/aspects relevant to the genome project, were assembled. The meeting ended with a fantastic dinner at the St. John’s College, where they offered many of us way too much wine and port.

All in all, the HGC seems to have a solid game plan, a strong group of interested researchers, some money, and data pouring in, making it very soon that we can expect to see good working draft of the Heliconius genome.

Heliconius melpomene aglaope processing a pollen load.  Adults may spend several hours processing pollen, producing saliva which is mixed with the pollen to release amino acids and then ingested.  The large grains of white pollen in the photo are from Psiguria warcewiczii.

Accommodation will be available from Weds 24th until Friday inclusive at no cost, thanks to support from St Johns College.  The meeting will be held in the Old Music Room in St Johns College. For a map of college, see here.

Draft schedule:

Thursday 25th March

• Morning – Assembly of a reference genome. A brief description of the data collected so far and status of the current assembly. Discussion of priorities for obtaining an improved assembly of the reference genome.
• Comparative genomics goals. Review of the scientific goals outlined at the previous meeting for genome resequencing and comparative genomics.  Discussion of resequencing data obtained so far (if any) and goals for remaining funds in the initial round of money.
• Afternoon – Annotation and databasing. Discussion of tools available for genome annotation and databasing.  Assignment of tasks to different research groups.
• Publication plans. Discuss plans for publication of the genome, and in particular for how further data collection might be focused.

Friday 26th March

• Morning – Presentations and comments from non-HGC members. Attendees with experience in genomics of other organisms will be invited to briefly introduce their own interests and comment on the project.
• Afternoon – Future plans. Outline specific plans for grant proposals to take advantage of the preliminary data.
• Conference Dinner in the Wordsworth Room of St Johns College at 7 for 7:30pm (let me know of vegetarian/dietary requirements)

Homework: Please try to have a look at previous genome papers with a mind to what we want to achieve in ours.  Here is a Zip file with some recent papers to look at.

Attendees (with accommodation)

Mark Blaxter (not friday)
John Davey
Brian Counterman
Richard ffrench-Constant
Paul Wilkinson (veg)
Alexie Papanicolaou
Jim Mallet
Owen McMillan
Marcus Kronforst
Nicola Chamberlain
Bob Reed
Chris Elsik
Stephen Richards
Sean Mullen
Riccardo Papa
Rainer Lehtonen
Mathieu Joron
Lise Frezel
Marian Goldsmith
Durrell Kapan

Attendees (no accommodation)

Kanchon Dahamasapatra
Jamie Walters
Gos Micklem
Adrian Carr
Daniel Lawson
Simon Baxter
Laura Ferguson
Nicola Nadeau
Rob Jones
Richard Merrill
Adam Spargo
Annabel Whibley

Travel
A couple of people have asked me about travel to Cambridge from the US, so I thought I’d send out a general email rather than replying individually. The closest airport is London Stansted but unfortunately not many transatlantic flights go into there. So you are most likely to be looking at a flight to either London Heathrow or London Gatwick. Both of these are a couple of hours travel from Cambridge, either by bus or train. I tend to prefer the bus from Heathrow (this avoids using the London Underground, which can be hectic at busy times), and the train from Gatwick (you should get a ThamesLink train to Kings Cross St Pancras, from where you can change to the train for Cambridge – avoid the Gatwick Express which goes to Victoria station).

See also the University web pages about travel

Heliconius hecale melicerta, from Gamboa area, Panama

Heliconius erato petiverana roosting gregariously in the insectary in Gamboa