Author Archives: Studio Schilthuizen

About Studio Schilthuizen

Ecology and Evolution for Everyone. I blog, write, and speak about biodiversity and the science of life on earth.

A literary event at Teylers Museum

viber-imageToday was Darwin Day — February 12th, the birth date of the great man. All the more fitting that today was the first in another series of scientific-literary events at the legendary Teylers Museum in Haarlem. Legendary, because it has been preserved pretty much in the state of its birth, in the late 18th century. Today’s event, expertly guided by Alexander Reeuwijk and Norbert Peeters, themselves successful writers on Wallace and Darwin,
consisted of “illc4engzbxaaeestd-jpg-largeustrated interviews” with Kees Moeliker, Jelle Reumer, and yours truly. (Photos by Iva Njunjić and Kees Moeliker.)


Taxon Expeditions: Moving Pictures

I proudly present the promotional video that we made for our new citizen science enterprise Taxon Expeditions. Check it out, and please share it widely. The video was compiled mostly from footage taken during our 2016 field course in Borneo, during which the idea of Taxon Expeditions was conceived (on a boat ride on the Kinabatangan river). We have also used ecodrone foorage by Sol Milne, and some clips shot by our student Sophie van der Hart (among others, amazing pictures of an orangutan female with baby).

Invasive species and the perils of terminology

exotic_species_alert_for_mississippi_river_from_minnesota_department_of_natural_resourcesIn an opinion paper in Trends in Ecology and Evolution, James Russell and Tim Blackburn signal a rise in what they perceive as “invasive species denialism”. They state that more and more publications, including some in leading scientific and popular science media (e.g., Fred Pearce’s New Scientist article and the book Where Do Camels Belong? of Ken Thompson) “have challenged the existing scientific consensus” on invasive alien species (IAS). That scientific consensus, say Russell and Blackburn, is that invasive alien species cause serious damage by their global change of ecosystems. And, the authors argue, this rising trend of “IAS denialism” among scientists and science reporters is fuelled by political motives and employs selective use of research data. The parallel with denialism in global climate change is obvious, and alarming.

Russell and Blackburn then go on to show how to recognise and deal with IAS denialism. They first explain that legitimate scientific debate may exist over whether a species may classify as “invasive” and that there is the non-scientific assessment of value in deciding what is “damage”. Having said that, Russell and Blackburn then state that “[i]n some cases the rejection of scientific evidence of the negative impacts of IAS takes the form of a type of science denialism.” That is, “to manufacture uncertainty in the scientific consensus on an otherwise undisputed topic”. The political motives that lie behind this denialism are said to be those idealising free trade, the very enterprise that causes many of the harmful species introductions in the first place.

I have read Russell and Blackburn’s paper with increasing alarm. Because what do they really say? First, that species invade and that such invasives may be perceived as harmful. Second, that the assessment of “harm” can be subjective. And finally, that scientists should not cast undue doubt on undisputed scientific facts that invasive species cause harm and thus play in the hands of those grinding a political axe. However, the parallel with climate change, appealing though it may be, is not warranted. Denialism in climate change takes the form of casting aside scientific evidence that the global climate is changing. Similar denialism in the field of IAS would be a denial that more and more alien species are invading ecosystems, and nobody is denying this fact. What is debated  is whether these invasions cause harm and, if so, on what time-scale. Since “harm” (unlike global temperature) cannot be objectively defined, the so-called “IAS denialism” lies outside of the realm of science and cannot be pinned on ecologists that happen to take a different view on invasive species than Russell and Blackburn.

What does lie within the realm of science are discussions on how energy flows within ecosystems are affected by species invasions, and how invasive species and the native species they interact with may evolve, and at what temporal scales. By casting such debates as “denialism”, Russell and Blackburn are not doing their colleagues a favour. By drawing an unjustified parallel with climate change denialism, their paper constitutes a pre-disapproval of ecologists who are trying to explore the concept of novel ecosystems, or take a long-term view of micro-evolutionary reconstitution of invaded ecosystems. I would take issue with labelling such ecological viewpoints as denialism. Rather, they are a legitimate way of dealing with the long-term effects of invasive species. Perhaps even more responsible than uncritically walking the conventional line of viewing IAS as one of the major challenges to biodiversity conservation of our time.

Russell and Blackburn end their paper by writing: “There should be a vibrant and robust dialogue on the negative, and potentially any positive, impacts of IAS and on the allocation of resources to remediate their diverse threats.” However, “such a discussion should be evidence based and not disrupted by appeals to values or denial of the magnitude of the threat. We believe it is imperative that invasion biologists engage constructively and lead on such discussions”. I could not agree more. But with this paper, the authors achieve the opposite. By drawing parallels with climate change denialism, they aid in creating an atmosphere in which any scientist exploring an unconventional long-term view on the issue of species invasions, may be labelled as politically incorrect.

Paperback is out!

On April 28th, the paperback edition of Nature’s Nether Regions appears in the US (on May 14th in the UK). With a quirky, young-adultish cover, and a delightful quote from Isabella Rossellini, I hope it will open up a new segment of the readership. To promote the paperback version, some excerpts have been published, and I’ll be on a book tour in the UK 20-30 May.nether-regions

Burying Beetles Play for Both Teams

Since Bruce Bagemihl‘s wonderful book Biological Exuberance (and Ricky Gervais’s stage adaptation of it), there’s no denying the fact that homosexuality is everywhere in the animal kingdom. Not as the occasional embarassing mistake, but often as a standard part of the sexual repertoire. Clearly, homosexuality has evolved in many species, but the question is, how and why? Since evolution works via success in spreading one’s genes, how could a behaviour that is not primarily geared towards leaving offspring, be advantageous?

The crucial word here is “directly”. Perhaps in most cases homosexuality itself is not *directly* advantageous, but it may be indirectly so. One example of this has just been published in the journal Biology Letters. Katharina Engel and colleagues of the University of Ulm, Germany, studied the burying beetle Nicrophorus vespilloides. This is a common beetle in Europe and Asia, known for its habit of interring dead animals (small birds or rodents, usually) and then tending the buried cadaver as food for their young. (In fact, they are one of the few kinds on insect where the parents care for the young larvae till they are grown up.)

In the scramble around a newly-discovered corpse, where many beetles will vie for the right to take possession of the corpse, male beetles face great risks but also great opportunities: if a male manages to outcompete rivals *and* fertilize the female that eventually is going to lay its eggs on the dead mouse, it will have reached its reproductive goal. And, as Engel and colleagues discovered, whether these males will engage in any gayness, will depend on how frantic the scramble around the mouse is.

They conducted two experiments.

In the first one, they placed males in cages with zero, one, or three females. After several weeks, they introduced such males to other males to see whether they would fancy them. The beetles that had been housed with females would never mount another male, but the males that had been housed in celibacy, would be more so inclined. So, the researchers say, males that “think” females are few and far between, won’t let a potential female get away, even if the female is actually a male. In other words, they can no longer afford to check first.

In the second experiment, they kept males in isolation for 60 days and then gave some a dead mouse and some not. Then, they introduced a male “lover”. As it turned out, the males-with-a-mouse were less likely to try to mate with the new male than the males-without-a-mouse. The explanation in this case is that the other male will be more inclined to fight the starry-eyed male if there’s food around that’s worth fighting for. So in this case, mounting a potential female and running the risk that it turns out to be a male, is a wise choice only if there’s little risk that the male (if in fact it turns out to be one) will bite back.

A heterosexual copulation in the burying beetle Nicrophorus vespilloides (male on top). Photo by Heiko Bellmann (from the Biology Letters paper--supplementary information)

A (heterosexual) copulation in the burying beetle Nicrophorus vespilloides (male on top). Photo by Heiko Bellmann (from the Biology Letters paper–supplementary information)

In conclusion, in male burying beetles, homosexuality seems to be an option born out of the risk of missing out on a heterosexual encounter with a real female.

Stay tuned for more discoveries from the realm of biological exuberance.