May 6, 2013

Importance of rearing caterpillars and its parasitoids

A month ago I had the great opportunity and honor of visiting Mark Shaw in Scotland, and Kees van Achterberg in the Netherlands. Today I will be writing about my stay with Mark, and what I learned from his extraordinary collection.

The first thing I realized was how few I know on parasitoid biology, especially compared to what Mark knows. It is a humbling experience to listen to him talking about particular species of wasps attacking particular species of caterpillars -and on determined plants, at different moments of the season/year! Here in North America we are light-years away of that kind of knowledge. By comparison, we know nothing.

Another thing I learned was to not be fooled by the appearances. Mark's collection (photos below) might seem a bit rustic... but make no mistake, you are contemplating one of the greatest resources available about biology and ecology of Lepidoptera-parasitoid wasps.

The collection -which in due time will be transferred to proper wooden drawers and deposited in the National Museums of Scotland, in Edinburgh- mostly comprises thousands of specimens collected by Mark during the last 2-3 decades. Decades he spent patiently rearing caterpillars, mostly in the United Kingdom, but also in many places across Europe. There are hundreds of new host records, and valuable ecological information on the wasps species, mostly Braconidae, but also Ichneumonidae and a few other families of Hymenoptera parasitoids.

During my 5-days visit I only had time to study 2 genera of Microgastrinae, and could not even finish with them. Going through the collection I was amazed to see the richness of the data gathered by Mark. And, as a greedy person gathering golden coins from a treasure coffin, I spent my last two days frantically recording data and typing notes in my laptop... 

I left with enough information to prepare with Mark 4-5 different papers on Microgastrinae, papers which I believe will be of importance for future researches on biocontrol at Holarctic level. But that was just scratching the surface of what can be done. Thus, we really expect -and hope!- to continue this work in the near future.

As I waited in the Edinburgh airport for my next flight to Amsterdam to visit Kees (I will write about that second part of my trip in a different post) I tried to reflect on the value of what Mark has done over the years. It all starts with his passion for carefully rearing all kinds of caterpillars, taking notes on everything -dates, host plants, time to emerge, cocoons details... Mark has a shed in his house (shown in the left photo below) where he keeps every individual caterpillar at a temperature as close as possible to the conditions found in the wild -where the specimens were collected. To do that, the shed is protected by the shadow of some trees, and a screen door allows for ventilation while protecting from unwanted animals to enter.

Then comes his vast knowledge on where to find caterpillars, and how to collect them. Then comes his also considerable knowledge of many groups of parasitoid wasps that go after those caterpillars. And then comes the perseverance of keeping that work for years and years. Each time getting additional and new data, filling-in gaps, refining the whole picture of parasitoid-host relationships...

One afternoon Mark took me to the Museum, to briefly show me the place where he had worked for so many years. As we quickly walked through the exhibitions, Mark pointed to me the taxidermied remnants of the sheep Dolly, the first mammal to be cloned from an adult somatic cell in 1996. While I took a photo of the famous animal, by accident I caught Mark in the background. 

Then I thought: "if we really want to advance the researches on biological control of caterpillars using parasitoid wasps, we are going to need to clone several copies of Mark". And I cannot think of a better homage to him than that ;-)

[I also want to thank Fran, Mark's wife, for her tremendous hospitality and support during my visit]. 

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