Divergent Evolution: Arabs, Israelis and Blind Mole Rats

A mole rat trap

Our first night in northern Israel, rockets from Lebanon landed not 50 kilometers from the field site. For the Israeli scientists in the group, this was no big deal. ?Small ones, only matter if they hit your house,? an Israeli said to reassure his Czech colleagues, whose eyes reflexively widened at the mention of bombs. The Palestinians, here from the West Bank on special work permits, did not find it too concerning either. Rocket fire makes news every few weeks in Israel, but actual fatalities are rare.

What brought this diverse group together was research on the blind mole rat, a furry sausage with comically prominent teeth. Blind mole rats make their burrows underground, hence the blindness?their eyes are covered by a layer of skin?and large teeth, which they use to dig through the dirt. They?re so common in Israel that on the drive up, Eviatar Nevo kept pointing out mole rat mounds along the highway.

Radim (l) and Jan setting traps

Nevo has been studying blind mole rats in Israel for over 50 years, amassing more than 300 publications and posters about them. (Mole rats comprise only one of his many research interests, and he?s supervising me on a different research project on fruit flies.) A professor emeritus at Haifa University and founder of its Institute of Evolution, he shows no signs of slowing down at 83. He?s the one leading the charge through thorny bushes and rocky hills in the field.

?This is basalt,? Nevo said pointing to the ground, ?and that is chalk,? this time pointing across the hill. His simple statement captured why we were in this particular field. A geological fault splits the field in two, with white chalk soil densely covered in thorny burnet shrubs on one side and sparsely vegetated, clay-like basalt soil on the other. According to Nevo, the mole rats here have adapted to two different environments, and a 2003 paper reported genetic divergence between populations living in the two soils. This different from that classic example of adaptation in the Galapagos because unlike the isolated islands, there is nothing to prevent mole rats in the chalk from interacting with mole rats in the basalt and vice versa. Yet DNA evidence suggests they?re going their respective ways.

Ali holding up a mole rat

To study the actual behavior of these mole rats underground, Nevo brought in Radim ?umbera and Jan ?kl?ba, experienced radio trackers from the University of South Bohemia in the Czech Republic. This was the first of two trips to Israel for their researching group. In this initial trip, they?re catching mole rats to fit with radio collars. A second trip in January will include radio tracking and mapping of the burrow systems. Radim and Jan had spent months studying subterranean rodents in Africa, so they are quite handy with traps, radio equipment, and the most basic tool of mole rat scientists, the hoe.

A hoe is all Ali and Hassan, the Arab hunters from the West Bank, used to catch mole rats. Nevo has been employing Arab hunters to catch mole rats since the 70s, and it?s been so long that nobody remembers the exact circumstances of how they first met. Ali recalls first learning to catch them after meeting an Israeli scientist, who was not Nevo, catching mole rats in the West Bank back when the border was less restricted. Getting West Bank residents into Israel these days is no easy task. With unemployment in the West Bank at 25% and higher wages in Israel, many are eager to work here. To secure eight-day work permits for Ali and Hassan, Nevo was sending letters every day to the government office.

Over the decades a collegial relationship has developed between the Israeli scientists and the Palestinian hunters. Ali brought two liters of hummus from the West Bank, which Jan ate by spreading like butter on his pita bread. (The proper way to eat hummus: rip up the pita and dig in with your hands.)

Food is not the only place where differences crop up in an international collaboration. Radim and Jan don?t speak Hebrew or Arabic while Ali and Hassan don?t speak English or Czech. On the first day, Radim was trying to explain through a translator why he wanted mole rats from both the basalt and the chalk. The chalk?s dense cover of shrubs made it difficult to catch mole rats, especially because there are also just fewer mole rats living in chalk.

Contrast between basalt and chalk

For Ali and Hassan looking to maximize their catch, it made more sense to stay on the basalt. Of course, this undermined the scientific purpose of this study, which is to compare the two populations. Explaining this fact took several minutes and several apprehensive glances back and forth during the translation, but the message was eventually delivered.

As the Czechs went to set their traps, Ali and Hassan took their hoes out into the field. Hunting mole rats is a matter of patience. First, the hunters open up the mound to expose the tunnel running underneath. Then they wait ? ?sometimes 30 minutes, sometimes all day? according to Ali. The mole rat will eventually come out to fix its mound when it senses air rushing through. Then a quick whack with the hoe right behind the animal, blocking its escape path back into the tunnel. Caught.

Truth is, field work is large stretches of boredom. This is not so different from the lab bench, except the weather is not temperature-controlled (December is chilly) and the animals are scurrying around who-knows-where rather than organized in neat cages. For hours, the Czechs went around setting and checking traps, and the Palestinians waited at their open mounds. Nothing happened. ?In Africa, I was sitting like this all day,? said Radim squatting down next to a mound with his hoe ready, ?I was going crazy.?

Jan radiotracking

Ali caught the first animal. He walked over as it whirred like a wind-up toy in his hand. The mole rat that seemed so clever and diabolic underground ? one clogged up a trap so compactly with dirt that I made no headway attempting to clear it for twenty minutes ? was out of its element in the open air. Even if you put it down on the ground, it doesn?t run off, not knowing where to run when there are no tunnels.

The first day in the field ended with six mole rats. Traps: 4, hunters: 2 ? far exceeding Radim?s expectations. ?Six!? he said, holding up fingers from two hands. With seven more days of trapping ahead, they werewell on their way to the goal of 30.

Aside from fitting the mole rats with radio collars, the researchers are planning other comparative experiments: DNA sequencing, X-rays, and vocalization recordings. The ultimate goal is a comprehensive understanding of the physical and behavioral differences between the two neighboring chalk and basalt populations. Living just 100 meters apart, do they ever interact? How different are they?

Nevo has in his office a color-coded map of the four blind mole rat species in Israel. His map only covers Israel, but mole rats live all over the Middle East in flagrant disregard of international borders. For humans however, borders are not so easily traversed. Nevo has expressed interest in studying mole rats in Libya, but as with nearly all Arab countries, travelers with an Israeli visa, let alone an Israeli passport, are barred from entry. The border between Israel and Lebanon is just as impassable. But if you climb up a hill at the chalk-basalt field site, you can see on the next mountaintop a Lebanese town, just five kilometers away.

Source: http://rss.sciam.com/click.phdo?i=4bdc9aa74350d7d2b3d297e21bbad5f9

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