What could one do with 250 000 SEK? A stepping stone towards a thermal image camera

Well, today I found out that I was awarded 250 000 SEK from The Crafoord Foundation, which is for an application I did send in this winter to buy a thermal image camera. This type of camera does of course cost more (around 400 000), but it is at least a start, and hopefully more money from other funding sources will come in so that I can eventually buy it to my research laboratory.

As some of you already know, I am interested in thermal image camera as a novel tool to quantify insect thermoregulation, and relate such variation to other interesting things, such as genotypes, phenotypes (e. g. wing colouration patterns), species or heritable colour morphs.

One recent scientific application where such an IR-camera has been used has been to look at differences between pygmy phenotypes in humans and normal-sized people (see picture above). One of the hypotheses for the evolution of small stature in many populations of humans inhabiting rainforest environments across the globe (Asia, Africa, South America) has been that short men and women do not have as much trouble with excess heat as tall men and women. This thermoregulation hypothesis, as well as other adaptive hypotheses for the evolution of the pygmy phenotype was recently discussed in a TREE-review by Perry and Dominier.

Back to the Crafoord Foundation. Although I am somewhat disappointed that I did not get the full amount I applied for, I am definitely happy that my hard-working scientific "Animal Ecology"-colleagues Staffan Bensch, Anders Hedenström and Susanne Åkesson also got grants from Crafoord. Money is not everything in research. But with money one can (sometimes!) do good research.

Genetics of pygmy evolution in Africa

Some of you might be interested in a recent study about the evolutionary origins of African human pygmy populations, which is discussed in this bloggpost. A recent study have investigated the molecular genetic history of African pygmy populations and concluded that they are not secondarily derived from the farming populations of the Bantu people. Instead, the different and the isolated pygmy populations in the African rainforests are historical relicts of a greater contiguous population of an ancestral hunter-gather society that was split up in to different fragmented populations when the African Bantu people expanded about 10 000 years ago.

The different pygmy populations in Africa have thus not evolved their short body stature in parallel. Rather their phenotypic traits are traits that they inherited from their ancestors. The pygmy populations and the Bantu people have been separated for at least 60 000 years. The agricultural revolution took place the last 10 000 years, and when the Bantu people brought agriculture to sub-saharan Africa, their population sizes exploded. This is because the carrying capacity of agricultural populations is considerably higher than for hunter-gather societies. which is not very surprising. After all, by using agriculture you can feed a much larger population per unit area than you could by hunting.

The pygmies were thus marginalized by the rapidly expanding Bantu-farmers, and their once large population was split up in to several smaller fragmented populations. The once more widespread pygmies are today more less isolated from each other in the deep African rainforest.

As an aside, this is an interesting example of how population genetics, particularly the use of the population genetic software STRUCTURE, can be fruitfully used to infer population histories and population genetic parameters (see figure above). This is something we are also working on in our laboratory, particularly Anna in her studies of Mediterranean Podarcis-lizards.