> The emergence period of large prime numbers (13 and 17 years) was hypothesized to be a predator avoidance strategy adopted to eliminate the possibility of potential predators receiving periodic population boosts by synchronizing their own generations to divisors of the cicada emergence period. Another viewpoint holds that the prime-numbered developmental times represent an adaptation to prevent hybridization between broods with different cycles during a period of heavy selection pressure brought on by isolated and lowered populations during Pleistocene glacial stadia, and that predator satiation is a short-term maintenance strategy.
Classic devops trick. Schedule your jobs at prime intervals - this way it's much less likely to get concentrated waves of traffic at 0:00, or 12:00, or in exact 15-minute increments.
Excellent advice. Good for programming in general when it comes to sleeps or waits and such. If you have multiples of 10s everywhere when an error happens every, say, 10 or 20 seconds, it might be hard to tell where it's coming from. But if you make them relatively prime to each other, you can can easily tell: "Oh it happens every 37 seconds? I know exactly what that is!"
Many cron systems have this functionality. At least anacron and cronie (RHEL) supports the RANDOM_DELAY variable. Check your man 5 crontab.
There's also systemd timers which can replace cron jobs with RandomizedDelay.
Before that, people used to include a random sleep in the actual job.
Personally, I tend to not use these things and instead pick a random start time when provisioning the job. That way the time delta between run is constant, which is often desired.
The first idea doesn't make sense to me. What evolutionary tool did cicadas have access to that would enable them to do something which the predators would be unable to do?
I've only once seen an outbreak of locusts and I hope I'll never see one again, it still gives me the creeps more than a decade later. Everything covered in insects, as far as you could see. This was in Northern Canada, just South of Sudbury, near the Magnetawan river.
I'd never seen anything like that ever before, I had to stop for gas, saw a few insects land, went in to pay and by the time I wanted to go back to the car it was literally covered in insects, there was no way to get into it without bringing a few hundred of them along. I ended up waiting out the worst of it.
Horror movies really don't capture the feeling well.
Cicadas aren't locusts. They don't really swarm like locusts its just that there are a lot of them at the same time. Locusts are really just stressed out grasshoppers.
Locusts have been extinct in North America since about 1930.
The biggest plague used to be the Rocky Mountain locust, which would cover every surface for days, utterly destroying farms. Those went extinct in about 1905. The High Plains Locusts went extinct in about 1930. [1]
There are various theories about why they went extinct -- something to do with what the settlers and farmers were doing to the land. But it wasn't an obvious culprit like pesticide, which wasn't really in widespread use until about the 40s.
I'm actually worried they won't show up in the numbers they're expected to. I've read several old stories about thick clouds of birds and/or insects literally eclipsing the sun (the biblical plagues of egypt is one notorious example), but then I also read some recent articles about how some species that used to show up seasonally in large swarms suddenly had their numbers drastically decreased one year (monarch butterflies are a famous instance of this)
As I understand it, the largest consensus around probable cause for that decrease has to do with neonicotinoid pesticides, which both bioaccumulate and also affect many more species than their intended targets. I don't actually know whether larvae of a brood that's been underground for over a decade would be more or less likely to be exposed to concentrations significant enough to do harm.
An echo of the clouds of birds is a daily “commute” of black crows in Charlottetown, Prince Edward Island.
Around sunrise, they head to forested land northeast of the city. At sundown, they head back to their roosting grounds in Victoria Park. The sky is filled with hundreds of crows for approximately 10 to 15 minutes during this rush hour. It’s absolutely fascinating to watch.
Every so often, you get to be “lucky” winner of them roosting in a tree in your back yard overnight. They cackle throughout the night. Anything under the tree will be caked in droppings by morning.
Crows are way too smart for decoys or actual scarecrows. The only thing that scares them away would be an owl or another dead crow. Someone did try shoot one early last year, but police investigated because setting off a firearm is prohibited within city limits.
> I've only once seen an outbreak of locusts and I hope I'll never see one again, it still gives me the creeps more than a decade later. Everything covered in insects, as far as you could see.
There is a locust swarm in Things Fall Apart (a work of fiction) which is viewed as cause for celebration. The locusts cover everything and eat the crops -- but they can be harvested and eaten themselves.
I was just in the Brazilian Amazon, and there was a funny moment there re: spiders... I stepped out onto a small floating dock and my weight sank the bottom of the dock below water level. There were probably ~100 spiders of all sizes that immediately emerged around my feet from between the slats as they were forced out from their homes underneath the dock.
Fortunately I don't mind spiders much, but it did look like a scene out of a horror movie.
Thanks for the details. I've now added a new entry to my list of places never to go. I do hope those little guys were able to resettle somewhere less prone to anthropogenic climate change ;)
Places to Avoid, list written + maintained by Arthur Collé:
[] Deep space [added: after seeing Gravity]
[] Mariana Trench [added: after seeing Underwater]
My brother told me to climb under an outdoor couch in Texas when I was about 6 and I was immediately covered by hundreds of harvestmen (aka daddy long legs.) I remember being startled and yelling for help but was not permanently scarred or anything. Spiders only creep me out the usual amount.
I remember Underwater for skipping fast forward after the first five to ten minutes, and it sounded almost comically. Just varying screems to the end. And way too much "teal and orange".
In Texas 100 years ago tarantulas used to be so thick crossing highways that cars had to stop. I haven't seen reports of quite that many in the last few decades. These are always males looking for mates. They are venomous but rarely bite and their venom is no more dangerous to people than a bee sting (i.e. it can be dangerous if you're allergic). They make good pets although wild-caught ones don't live long.
As kids we would catch them and keep them in jars for a few days, then release them again. We also caught king snakes and fed them blue belly lizards...which may lead you to understand our fear response with wild animals.
... we've all heard the factoid that the average person supposedly eats 4 spiders per second. This statistic is misleading; it's based on a study examining on the peak rate of spider consumption in areas where the spider-streams are densest. The global average rate is probably closer to 1 spider per second (obviously higher while asleep than while awake) ...
(For those who didn't click, note that What-If #120 is "Excerpts from What If articles written in a world which, thankfully, is not the one we live in")
Then better not visit the "Hafen City" in Hamburg, Germany.
Especially not the latest metro station "Elbbrücken" there, and especially not at night, because then they come out to hunt all the other insects which are caught in their nets, which they build over or near any light. Even over the touch screens of the ticket machines. They seem to be E-V-E-R-Y-W-H-E-R-E! BRRR!
I was in DC in 2004 when they came out last time. I don’t recall any concerns about agriculture and nothing in our yard got damaged. You just had to clean up a lot of dead cicadas. I think most of their feeding is done underground and they come out to mate and then die. It’s not like locusts that eat everything in their way. Birds were super happy though.
It stlll impresses me that they are better at keeping track of years than I am.
"What is Brood X, the infestation coming in 2021? They're big. They're incredibly loud. And they're coming by the billions." "That phenomenon is named Brood X, or the Great Eastern Brood"
That sounds like something from Starcraft or Warhammer 40k.
Interesting. I had remembered one spring/summer in Illinois from my childhood where there were just so many cicadas. Everytime the wind shifted you'd hear them drone on, the buzzing slowly shifting between loud and soft all day. The volume was quite remarkable.
I hadn't thought about it in a long time. Fun memories.
It's rather depressing honestly. The catastrophic risk of ecosystem collapse aside, when I have kids it'll be sad if I can't catch fireflies/lightning bugs with them since the bugs seem to be dying out.
I was expecting some site about the old Cicada-something "group", which caused quite a scene a couple of years ago, but instead entered a rabbit hole on the actual insect.
Great info, and we do have a lot of Cicadas here in Brazil at this time of the year, wonder if perhaps there are similar broods.
Hah!, The headline triggered my automatic counting of letters and segments looking for prime number cribs as well. Have so far resisted the urge to check pixel dimensions on images, stego fingerprints, hidden rune thumbnails, exif data, but what happens if I xor these images together...
There are both annual and periodic cicadas. I lived through a 17 year bloom (there are also 13 year cicadas in the US), and it’s quite different from the usual numbers.
According to wiki, it seems like the periodic broods are solely within the US/Canada.
What an interesting phenomenon to experience. I was a kid during the 2004 surge and it was incredibly striking. Literally everywhere you looked outside, the ground was covered with dead cicadas, and it was even difficult to just walk outdoors without a cicada flying into you or landing on you. If you haven't seen a cicada, imagine an insect about the size of a man's thumb, with wings about as long.
As a kid it was novel, if gross, With people cooped up inside these days, I feel like it'll be less of an issue.
I'm looking forward to this! Granted, wasps will I think always be my favorites for macro photography - there's just something about getting to see them so close and in such detail that appeals to me in a way I don't quite know how to describe. But I didn't have a macro lens for the last significant brood emergence here, back in 2017, and especially after the privations of 2020's lockdowns I think I'll really enjoy the opportunity to see cicadas in the same kind of detail.
I live right in the heart of this brood's range (Cincinnati, Ohio) and was about 10 years old the last time it emerged. I'm super excited for this spring/summer! It is an incredible sight and sound to see so many cicadas everywhere!
I was near Cincinnati as well when the last brood came out. The sound was incredible. Kinda sad I'm missing it this year but at least I was able to experience it at least once.
It's odd that the data for the locations of emergence happen to respect state lines. Is there no data for South Carolina, or do cicadas prefer not to visit that state? Perhaps the website says somewhere, but I didn't go down that rabbit hole.
I noticed this because Alabama is not listed as one of the 15 states, despite being nearly surrounded by cicada observations. And I know from experience that the northern part of the state gets swarmed with cicadas when they emerge.
Cicada groups split off while they occupied glaciated territory.
The Appalachia mountain range is famously, formed by glaciers.
The Valley and Ridge part of Appalachia, was a major highway of immigration and colonization. It is more likely that territory borders respect the geography and that the brood respects geography, rather than to each other.
A rough inspection of the brood distribution and the continental divides shows approximate respect to the St. Lawrence and Eastern Continental Divide.
There also seems to be some respect to the division between Mississipi Flyway and Atlantic flyway, which are bird migration routes.
It is my understanding that an organism highly dependent on deciduous forests will respect those regions and this includes most of the South.
Turns out, humans like deciduous forests too. They're useful for timber, charcoal and potash (fertilizer). The borders of this territory lines up pretty squarely with the border to Canada. That makes civilization a predator of the cicada through deforestation. The Onondaga brood is named for the Onondaga people.
As I understand, the Brood distribution effort is done by crowdsourcing.
Given the longevity of the brood cycle and the inconsistency in historical record, it could very well just be the case that the recency of this effort has not synced with an emergence.
That's my guess why cicadas and humans line up.
More practically, cicada cycles provided a necessary evolutionary flush of nutrients, bacteria and fungi across the distributions. They breed in such overwhelming numbers that the entire ecosystem of predators is likely to prosper from their emergence. So perhaps humans settle where there is game and timber, and where there is game and timber it is likely that the area prospered from a cicada cycle.
I had not thought about the possibility of a connection between locust and the increasing popularity of no-till farming. As I understand it, tilling is one of the primary causes of the decrease in locust swarm population and frequency over the last 100 years. No-till is on the rise, reaching 21% in 2017. I wonder if we will start to see more swarms in the future.
This is weird. I graduated outdoors in spring of 2005 and I remember a lot of cicada noise and people talked about this brood X being in 2005 not 2004. I usually would just assume my memory was off by one but I know which year I graduated.
We get a different species every few years in New Mexico. Their only downside is noise: They fill the forest with loud, random click sounds. It sounds creepy until you realize it's just the cicadas.
> The emergence period of large prime numbers (13 and 17 years) was hypothesized to be a predator avoidance strategy adopted to eliminate the possibility of potential predators receiving periodic population boosts by synchronizing their own generations to divisors of the cicada emergence period. Another viewpoint holds that the prime-numbered developmental times represent an adaptation to prevent hybridization between broods with different cycles during a period of heavy selection pressure brought on by isolated and lowered populations during Pleistocene glacial stadia, and that predator satiation is a short-term maintenance strategy.
Wow.