Arthropod average is over is bug co-residence a normal good?

Here is a new and intriguing paper by Leong,

In urban ecosystems, socioeconomics contribute to patterns of biodiversity. The ‘luxury effect’, in which wealthier neighbourhoods are more biologically diverse, has been observed for plants, birds, bats and lizards. Here, we used data from a survey of indoor arthropod diversity (defined throughout as family-level richness) from 50 urban houses and found that house size, surrounding vegetation, as well as mean neighbourhood income best predict the number of kinds of arthropods found indoors. Our finding, that homes in wealthier neighbourhoods host higher indoor arthropod diversity (consisting of primarily non-pest species), shows that the luxury effect can extend to the indoor environment. The effect of mean neighbourhood income on indoor arthropod diversity was particularly strong for individual houses that lacked high surrounding vegetation ground cover, suggesting that neighbourhood dynamics can compensate for local choices of homeowners. Our work suggests that the management of neighbourhoods and cities can have effects on biodiversity that can extend from trees and birds all the way to the arthropod life in bedrooms and basements.

Didn’t Paul Romer say this once?  Here is a Guardian summary of one point:

The researchers said the work overturns the “general perception” that homes in poorer neighbourhoods host more indoor arthropods.

For the pointers I thank Niroscience and Michelle Dawson.


Like attracting like? Did they compare lawyers homes to politician's homes to doctor's homes to banker's homes?

Let's see, in order, locusts, roaches, black widow spiders, and snakes. Or vice versa.

What if causality runs the other way… and arthropod diversity causes neighborhood wealth?

In my upper middle class neighborhood we enjoy roach milk with our roasted crickets. Urban farming!

In my house in a middle class neighborhood, ants are making heaps of earth on my concreted frontyard. The soil doesn't match my backyard or any yard around. I strongly suspect it is from below the house, which makes me wonder if it is bad.

If your yard has been concreted then the ants are probably bringing up sand which the concrete was laid on. I really don't think it's anything to worry about. But if you want peace of mind you can always try poking it back down the holes.

Thanks. I see no holes, only the heaps. Soon or later, I will have to find their tunnes e liquidate them, I guess.

Well, if they're anything like the ants around here, they'll just come back if you kill them. Mind you, ants are the dominate life form here in Australia. They can be over 20% of the animal biomass in a region. We have ants that live in trees, ants that live underwater, the world's least social ant, anti-monarchist ants that are giving up on having queens, and an ant that gets by with a single pair of chromosomes.

Wow. It is impressive. Anyway, I think I will prevail. As our forefathers used yo say cenruries ago, "either Brazil will succeed in destroying the saúva ( Atta -- or the saúva will succeed destroying Brazil)". No quarters given, mo quarters asked. We shll prevail.

Oh, Brazilian leaf cutting ants. And you want to fight them? Well, I hope you for one are prepared to welcome your new insect overlords.

We in Australia, with all our natural cunning and ant legions, could not defeat South American ants. Argentinian ants have taken over both Perth and Adelaide. They have slain all other ant species they have encountered, they kill birds, and rob bee hives. They used to bite me, but now they've given up on that. They know we're beat.

This fight has taken us two centuries since the goal of getting rid of the ants was arrived at, but we know the Brazilian people in its righteous might will win through to absolute victory. We are fighting for survival against a cruel, inhuman enemy. As French naturalist Saint-Hilaire said, "either Brazil will succeed in destroying the ant or the ant will succeed in destrying Brazil." We will settle for nothing except victory. Victory at all costs—Victory in spite of all terror—Victory, however long and hard the road may be, for without victory there is no survival. We will so bear ourselves, that if the Brazilian nation and its Republic last for a thousand years, men will still say, -"This was their finest hour".

Another sad face of growing economic inequality in America. The rich guys are hogging the arthropods for them and their cronies. More arthropods! More arthropods!

Sounds like an interesting article. As described in the post, the article correlates with common sense. A poor apartment may easily have several hundred or a few thousand cockroaches - all of one or two species - and a few other - a dozen or so, in my experience - (out of curiosity, and out of a desire to learn things that might make me more useful to my fellow humans, I moved into a cockroach-infested apartment complex for a few years back in the 90s and studied what would happen if I didn't use pesticides - the results were fascinating, although God knows if I had a young family living with me I would have moved out in less than half an hour) - visible species of more interesting bugs (the various centipedes were a fascinatingly repulsive extra, but the main portion of the diversity was comprised of several sorts of different thin beetles; the fat ones had mainly stayed outside due to a reasonable aversion for the difficulty of making it through the crevices between the indoors and outdoors). In contrast to a poor apartment, a rich home is going to have every type of cute little bug from the surrounding woods and gardens that for "random bug reasons" decides to wander into the rich home's warm confines at any bug-size entry that can be found. These lovable non-pests are less common in the neighborhoods of poor apartments. Article was, accurately speaking, about "diversity", not about "total number of bugs". "Random bug reasons" is a big number - not one of the biggest numbers that occurs in nature, of course, but one of the biggest numbers that occurs in the limited field of macrobiology (bugs and critters you can see without a magnifying glass). The bigger the woods and gardens the bigger and more diverse the number of random bug reasons. I don't miss the cockroaches, but I don't regret letting them live a happier life in my apartment than they might have elsewhere. Butterflies are of course more attractive, but I have to say the cockroaches showed affection for each other, and even a sort of bravery, that you don't often see in creatures of that size.

I could be wrong, but I believe that decades ago the legendary lepidopterist Robert Pyle stopped collecting butterflies - previously, he had found himself able to catch a butterfly he had just spotted, but unwilling to collect a butterfly that he had observed for more than a few moments. Eventually he stopped collecting them altogether, and merely observed and appreciated. I wish he would comment here once in a while.

I live in one of the most affluent neighborhoods in Silicon Valley, and 5 days ago I was bitten by a bug in the middle of the night. I thought it was a spider, and I tried to crush it. Then I turned on the light and saw what it was. It was a full-grown adult Jerusalem cricket. Google that if you want to see about the nastiest-looking bug that can bite you in the middle of the night.

They remind me of the eponymous insect in the game "Cootie".

Jerusalem crickets are ugly, but they're pretty small compared to some of the weta you find in New Zealand...

Who was that chap who used to take his pet lobster for a walk?

Nerval on lobsters - "tranquilles, secrets, savent les secrets de la mer" - loosely translated, they neither sing nor sleep, but they know the secrets of the Sea. (actually, tranquiles, secrets, they know the secrets of the sea).

Arthur Daley: "The world is your lobster, my son,"

Alfred Jarry, I believe.

Square footage per person relative housing type relative neighborhood zoning -> yard size -> vegetation diversity (in cities). File under obvious.

In the rural United States, biodiversity means poverty. I think Greenpeace knows why it opposes capitalism.

Memory Lane: When I lived in East Palo Alto (worst place in Silicon Valley, although it wasn't called that then, but great for a kid who liked boyish adventures on the salt flats etc.), We called them "Potato Bugs (i.e, Jeruselum Crickets), They gave me a new perspective on Jiminy Cricket. Too big to squash. Horrible mess if you tried. I still have nightmares. I'm 3,000 miles away now but I keep cans of bug spray all over the tiny little apartment I occupy. Creepy crawlies just as bad here too. I appreciate ecology but my philosophy is No Bugs in the House (partial exemption for little jumping spiders, which I study).
Trump will change all this if he's elected, I suspect.

Excellent post shared!! I'm really new to this topics but economic inequality is a familiar word. Hope it'll be solved soon.

The claim that these results 'overturns the “general perception” that homes in poorer neighbourhoods host more indoor arthropods' is false. These new results point toward greater diversity, not greater total numbers.

But hey, its The Guardian, where accuracy takes a back seat: "Homes in wealthier areas harbour more bugs, containing up to 200 different species of flies, spiders, beetles and ants, according to new research."

Partially in reply to Kimock; the writers at Science magazine sometimes have difficulty maintaining accuracy when reporting on ... Science... so let's go easy on the Guardian. Anyway, this little article is very politically charged; which is somehow common in ecology.

Back to the science;
There was no abundance data; so what considerations should be included when discussing the abundance, and would we expect based on the incidence data (done at the family level, for what it is worth)?

First, typically, collector's curves actually reflect increased abundance with lower diversity, because most diversity in a group follows a long-tailed distribution and collection effort saturates; so increased overall abundance ends up with a greater fraction from the most abundant organism.

Second, the 'green world' hypothesis suggests that top-down control is critical; particularly, top down control of lower trophic levels. These higher trophic levels tend to be larger organisms more easily observed, but relatively few in number. Sometimes they are called keystones because when herbivores, for example, are released from predation, primary production collapses. Bearing this is mind, the complexity is really hard to reconstruct from isolated incidence data on a single phylogenetic group.

Finally, there is the question of migration. Quite a bit was said in the article about gardens and vegetation; for example, in homes with high vegetation diversity in the garden, the connection between home value and arthropod diversity was lost. They hypothesized that home value was a proxy for community access to vegetation. An entire subfield is devoted to the species-area curve; so without recapitulating it, it raises questions about the diversity expected in (smaller, distributed) private gardens vs (aggregated) community green space. Could larger green spaces hold certain kinds of diversity, for example? Would that diversity be less likely to migrate out of the space? What are the trade-offs?


You realize that every time you do an "average is over" post you are guilty of confirmation bias right? Why not actively seek out contrary evidence?

you made a good point

Yes, but do the same results hold for Pokemon Go?

All through you first para you say wealthier neighborhood have more diversity.

Your next to the last line says the wealthier have more .

These are not necessarily the same. A plot can have a few but more divers bugs or just the opposite.

Oh my, yes. The Sinclairs next door just imported a lovely batch of New Zealand wetas, while I have a contact that has kept us flush with a number of Amazonian centipedes. Maisie's rose garden hosts a dizzying array of thirps, but we're all envious of the Leightons' collection of rare African dung beetles.

The common house fly for the common man, after all.

"Indoor arthropods" is such a delightful euphemism!

Sloppy journalism. More arthropods doesn't imply more arthropod species (genra, taxa, etc.) and vice versa. I have no idea what family income does to arthropod density (using any measure). Numbers, categories(species, taxa, ...) and biomass all could be rationally used as the unit of measure. More per what? Household? Sq meter? Is there more bug food in an affluent home? I don't know. More (unrestrained) pets or fewer? More cleaning (as measured by food removal) or less? More people or less? Seems to me if we're concerned with ecology, we should be using hectare, if disease/health that per person. A household is a social not an ecological unit. Linoleum floor vs shag carpet. House on a slab without basement or and barely a crawl way above ceiling vs house with full attic and basement and garage. Anyone who has a stereotype on which environment harbors "more" is either a lot smarter than me or hasn't thought about it much or both.

Amazing Post!! Informative survey, Bio diversity must be kept good for a mighty future for our planet.

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