Winged insects and degree of civilization
A recent article in Nature, which we blogged about here, reviewed the consequences of agriculture on the nature and prevalence of pathogens that have plagued human beings. One key datum that Wolfe et al. (2007) discuss is the difference between the vectors (or transmitters) of infectious disease in the tropical vs. non-tropical regions, where agriculture has flourished the longest: almost all of the nasty infectious diseases in the tropics are spread by winged insects [1], whereas most of those in the more advanced areas are spread by human-to-human contact, polluted water, or parasites of small animals (such as the fleas that spread the Bubonic Plague). One consequence of this is that, as the authors note, infectious diseases in the tropics tend to be chronic rather than acute — in crowded populations that characterize agricultural societies, it won’t take long for you to pass your germs to someone nearby, after which point you’ve served your purpose and can be left alone for the time being (if you aren’t shortly killed). If there aren’t many people nearby to infect, you’re going to have to serve as the host for much longer.
The authors do not note, however, an important evolutionary reason for why the geography of tropical regions causes them to be more plagued by insect-transmitted disease. This shortcoming is odd considering that one of the authors, Jared Diamond, has written best-selling books on human evolution (The Third Chimpanzee) and geography and civilization (Guns, Germs, and Steel). I haven’t read either of these in full, so to be sure he didn’t cover this issue in GGS, I searched it at Amazon and found no discussion of the prevalence of wingedness among insects. In any case, the key pattern is that the proportion of insects that are winged increases as both latitude and altitude decrease. At a more fine-grained level, wingedness is more common in habitats that are in some sense temporary or unstable, while flightlessness is more common in more permanent, stable habitats [2].
The basic insight comes from life history theory: in unstable habitats, an individual may be born into awful conditions due to temporal and/or spatial hetereogeneity. Here, it will pay to have a means of migrating to a more hospitable area, while in less volatile habitats an individual probably won’t get caught with their pants down, and so flightlessness would increase. Just think of the energy a bug would save by not growing and maintaining their wings if it didn’t need them. Most tropical areas have all three features: low in elevation, close to the equator, and more unstable habitat-wise [3]. It’s no surprise, then, that such areas are more wracked by insect-borne infectious diseases. There are simply far more winged bugs that can travel far distances transmitting pathogens to humans.
One consequence of all this chronic disease must surely be increased difficulty in founding, let alone maintaining, a great human civilization. Chronic diseases which begin to strike early on in life are likely one reason that mean sub-Saharan African IQ is about 70, while mean African-American IQ is about 85, a full standard-deviation above. Possible mechanisms are not difficult to think of: the parasite that causes Sleeping Sickness get into your brain and slowly destroys it, your body may divert resources to disease defense and repair rather than on “luxury” items like higher IQ, and so on.
Even controlling for IQ, being afflicted with chronic disease must sap one’s ability to doggedly pursue long-term projects, whether artistic or scientific, that foster civilization. Probably the best shot sub-Saharan Africa has is south of the Zambezi River, which doesn’t suffer from a tropical hellhole climate. At best they could reach the level of African-Americans, who don’t dominate Silicon Valley, but who have contributed scores more to the world’s culture than Africans in sub-Saharan Africa. [4] Even in the US, most high African-American culture has largely sprung from cities outside of the dreadful “humid subtropical” climate of the Southeastern states (for example, New York and Chicago).
That pattern is also evident among American Whites, by the way: at the most northern fringe of the Southeastern US there are first-rate research universities (Duke and UNC – Chapel Hill, both in North Carolina), but the region is largely bereft of civilization-propelling institutions. In fact, blogger Inductivist has shown, using General Social Survey data on Whites, that it is a larger source of and magnet for duller Whites, compared to other regions (see here and here). Now, clearly I’m not proposing that epidemic Sleeping Sickness, malaria, etc. are causing the problem in the US. But whatever the more numerous bugs in the Southeast are transmitting to humans, it could partially account for the discrepancy between its level of culture and that of the Northeast. Indeed, from Inductivist’s reckoning, it appears that most intelligent people with any sense from that region decide to haul ass to the Mid-Atlantic and New England states.
[1] From p. 280 of Wolfe et al:
A higher proportion of the diseases is transmitted by insect vectors in the tropics (8/10) than in the temperate zones (2/15) (P less than 0.005, chi-square test, degrees of freedom, d.f. = 51). This difference may be partly related to the seasonal cessations or declines of temperate insect activity.
[2] For a brief overview, see pp. 349-56 of Roff (2002). For extensive literature reviews, simulations, and so on, see Roff (1990) and Roff (1994).
[3] As for the non-obvious claim of greater temporal variation as you move toward tropical areas, see Roff (1990: 405):
I tested the hypothesis that habitat persistence varies with latitude with data on the rates of succession on abandoned farmland. In the northerly states of the United States (Wisconsin, New Jersey, Illinois, and New York) shrubs appear only 10-20 yr after abandonment, and even after 40 yr succession does not proceed beyond a very open woodland/parkland condition (Thomson 1943, Bard 1952, Bazzaz 1968,1975, Mellinger and McNaughton 1975, Pickett 1982), while in the more southerly states of North Carolina, Tennessee, and Georgia a closed canopy is formed within 15-30 yr (Billings 1938, Oosting 1942, Quarterman 1957, Nicholson and Monk 1974, 1975, Lindsay and Bratton 1980). In the Mexican tropics invasion by trees occurs within the first 2 yr, and these may reach a height of 10 m within 5 yr (Purata 1986): in the upper Rio Negro region of the Amazon Basin a loose canopy of Cecropia spp. 5 m high was formed within 22 mo (Uhl et al. 1981).
Sidebar: Detroit is fortunate to be situated as far north as it is, or else the reclamation of the city by the wild would have wholly swallowed up most of the area long ago (see here too).
[4] Alternatively, they could follow the lead of the elite strata of South Asia, who have managed to build a civilization despite vying with tropical Africa for status as the world’s chamberpot of infectious disease. There, though, the elites have striven for centuries to isolate themselves genetically from those in lower castes, as well as to minimize their physical contact with the even more bug-bitten lower classes.
References
Roff, D. (1990). The evolution of flightlessness in insects. Ecological Monographs, 60(4), 389-421.
——– (1994). Habitat persistence and the evolution of wing dimorphism in insects. The American Naturalist, 144(5), 772-98.
——– (2002). Life History Evolution. Sinauer Associates: Sunderland, MA.
Wolfe, N., C. Dunavan, & J. Diamond (2007). Origins of major human infectious diseases. Nature, 447, 279-83.
Labels: civilization, geography, pathogens, true redneck stereotypes
Even in the US, most high African-American culture has largely sprung from cities outside of the dreadful “humid subtropical” climate of the Southeastern states (for example, New York and Chicago).
an example: the innovation of techno and house music by african-americans occured in detroit and chicago, respectively
re: the south. your comment at inductivist’s place seems relevant:
I’d say it’s a current migration trend: smart people go where they can get rich, do research, be creative, or any combination. These places are pretty exclusively in the Bos-Wash corridor and the Pacific Coast. And though the Mountain region isn’t very creative or yuppie (except maybe Denver), there are lots of research / academic opportunities.
If you’re from the South or Midwest and are smart, you go to college and end up far away (though some return to Atlanta or Chicago).
So, just a here-and-now “brain drain.”
Hey, that’s my part of the country you’re knocking!
Seriously, though, there is a dearth of brains in the South. I left myself and only came back after having exhausted all other possibilities. It is hard to find intellectual companionship down here, but I found that to be true elsewhere as well. Everywhere except on GNXP! How many of you guys (and gals) have friends and acquaintences as versatile as some of the people on this site?
Anyway, with the internet and air-conditioning maybe intellect will make a come-back in the South. The cost of living is excellent, and in the land of the blind the one-eyed are king. We need some good small liberal arts colleges however.
State IQ and state latitude correlate at .52 for both whites and blacks, suggesting something reliably systematic lowering or raising IQ by geography.
Just how clever are Eskimos then?
There’s a lot of soul, character, and eccentricity (as well as food and music) to be enjoyed in the South, though. The creativity level (at least if your understanding of creativity encompasses fried chicken and yard art) is pretty high too, or so it seems to me whenever I pass through. Uninhibited, whacky people with a lot of superstitions and stories, and the space and time to do a lot of actin’-out — makes for loads of entertainment.
So, Agnostic, you’re pulling our leg at least a little, right? I mean you can’t be so ignorant of history that you fail to take into account that the American South was comprehensively destroyed about 140 years ago, economically, socially, educationally, politically and culturally. And there was no Marshall Plan rebuilding. Ever. It is only since the TVA and WWII that elements of industrialization started coming back into the South, and some portions of it are still greatly lacking any real economy.
Let’s see, we have an agriculturally-based rural society that largely had only been settled for 40 or 50 years from rawest wilderness, which arives on the cusp of industrialization, gets bombed back to the stone age, with an entire generation of the most ambitious men getting slaughtered in the process, then is governed by an occupation dictatorship for a dozen years or so through a class of people whose sole purpose was to enrich themselves on what was left of the economy at the expense of any locals, and then when that was over the region was ignored, exploited or villified by the rest of the Nation for most of a century.
And you think the mosquitos did it?
And, by the way, didn’t the high culture of the Indian subcontinent thrive for millenia in far more tropical latitudes than prevail in the American South?
Interesting theory.
MST
I have long thought the opposite: the stability and hospitality of the tropics are what make them so popular with parasites. High-latitude winters are not kind to either vectors or reservoirs.
MST, Germany and Japan revived pretty quickly after war, as China has done after basically waging war on itself under Mao.
Personal note: I’m originally from Minnesota, moved to a suburb of Atlanta for a few years when I was young, and nobody else there was from Georgia either. Since then I’ve lived in Illinois, so I can’t really say much about the South.
MST — you get one warning, and this is it.
The final text paragraph contains the key phrase “partially account for…” It’s a phrase that I used to assume even 2nd-grade dropouts would take for granted in these contexts, but I realized that morons need it pointed out explicitly, so that’s why it’s there — even if they’ll continue to ignore it. I’m suggesting just one factor among many for why tropical climates tend to ride back-seat to the more temperate climates.
Come on in! The humanity’s fine! Good people everywhere.
P.S. Ellen Gilchrist can write. James Webb is pretty smart. Lincoln weren’t half bad either.
It isn’t just a case of the former Confederacy = stupid, there is a linear trend for IQ and latitude for the United States.
… and the world for that matter. Within continents, between continents. Within racial groups, between racial groups.
I wonder how white children from the South adopted into a Wisconsin household would compare? I wonder if Northern pets (cats, dogs) would score higher on animal IQ tests than Southern pets? It’s possible there are cognitively harmful biological agents in less temperate areas.
I don’t leave the South because I love it (far from it), but merely because of inertia and my similar hatred and contempt for the citizens of everywhere else in these United States.
Please note, however, Quercus virginia, Magnolia grandiflora, Taxodium distichum, Pinus Palustris, et al. The Southern U.S. is home to one of the noblest forest communities on earth. Of course, morons are busily destroying that too.
Mosquitoes proliferate in wet northern lands, like Minnesota and Alaska. It would appear the main factor is dryness — warm Southern California has few mosquitoes.
Mosquitoes proliferate in wet northern lands, like Minnesota and Alaska
But do the mosquitos in those areas carry diseases that are harmful to humans?
Sorry Ag, but I was having an Occam’s Razor reaction coupled with running into what appeared to be another instance of contempt for the “non-coastals” that is rife on the coasts.
As I said, the winged insect theory is interesting, with the very suggestive latitudinal intelligence gradient, and certainly does account for the well-documented malarial lassitude in many countries, but you noted that neither malaria nor sleeping sickness are at play currently in the US South, and suggest unidentified pathogens to account for the some of the regional differences in the US, then mention the lack of cultural institutions, and that anybody with any intelligence and sense would haul ass out of the South.
Your mechanism would be: Biting Insects>Unknown Pathogen>Stupidity>Lack of Culture>Brain Drain>Feedback Stupidity
Mine is:Cultural Destruction>Brain Drain>Feedback Stupidity
Add Occam’s Razor: we know the Civil War with its subsequent aftershocks took place, with consequent centrifugal emigration effects. We don’t know your vector, pathogen or biological stupidity mechanism. I’ll opt for the simpler explanation, unless you can cite evidence it doesn’t explain.
On my other reaction, I’m working in the Northeast (for economic reasons-I’d be out West, otherwise), and encounter absolutely ridiculous expressions of ignorance and prejudice against the non-coastal people, particularly Southerners. I have been amazed at the parochial attitude of large sections of the populace here. Sorry if I took your attitude to be part and parcel with theirs.
MST (Apparently standing for Moronic Stupid Twit)
TGGP, please note my mention of the Marshal Plan. Wihthout us (US) rebuilding Germany and Japan, they would very likely have had a history arc similar to the South. Look at Eastern Germany for a better comparison.
As for China, it’s a nation of 1.3 billion people with a GDP almost equal to Germany at 82 milion. It comes out to about US$2k a head, but most of that goes to very few (coastal elites!). Maoism isn’t quite done with China yet. Yes, I think China will get there pretty quickly, but it is also getting economic aid through capital avaiablity and investment that the South never received.
MST, you should read Tyler Cowen’s The Marshall Plan: Myths and Realities. Western Germany has provided plenty of aid to East Germany, but it hasn’t done much good. Note also that England was the largest recipient of Marshall aid, but grew slower than many countries that were more devastated by the war and received much less aid. Furthermore, placing so much importance on the civil war (which I agree was very awful, especially for the South) ignores the significant differences between the North and South before the Civil War, which are discussed in Thomas Sowell’s “Black Rednecks and White Liberals”. The South had long had a less educated populace, and its most successful businesses tended to be run by foreigners, Northerners and Jews. That wasn’t caused by the civil war.
encounter absolutely ridiculous expressions of ignorance and prejudice against the non-coastal people, particularly Southerners
Why do people not see that this is wrong for the same reasons racism is? The Dixie Chicks told an audience in London that they were ashamed the President was from Texas. Somehow I don’t see them saying they’re ashamed the President is black.
TGGP, please note my mention of the Marshal Plan. Wihthout us (US) rebuilding Germany and Japan, they would very likely have had a history arc similar to the South.
In the Weimar period Germany’s economy was in absolute ruin. That was about a decade before they conquered Europe.
Look at Eastern Germany for a better comparison.
i.e. the most prosperous and successful communist nation ever.
In Guns Germs and Steel, Diamond did examine the distribution of parasites and concluded that this held back development in the tropics.
However he blamed the lack of freezing winters which would kill off many bugs in the colder countries.
Which if anyone has even been to the arctic during mosquito season would know, is not the full story.
Meanwhile I have another source of differentiation. Before the advent of air-conditioning, anyone who made any money moved to a cooler climate.
I’ve seen the results of this in India, all the mountain resort areas where the wealthy lived, while the lower castes were working the fields in the humid lowlands.
Wouldn’t this mean a steady drift of IQ and wealth to the temperate climates? At least before Air conditioning meant that you could cool a house as well as heat it.