Yeah, I did it again—clickbait. It’s an experiment to see if I get more than ten comments on a science post.
But this piece really does deserve an attention-getting headline, for the behavior of this spider, connected with its unique morphology, is astounding. You can read a short review in New Scientist, but I’m getting my facts here from the original paper: a new one published in Peckhamia by Jürgen Otto and David Hill (reference at bottom, free access). The journal, by the way, was named for George and Elizabeth Peckham (former 1845-1914, latter 1854-1940), a pair of teachers and entomologists who specialized in jumping spiders (salticids). As far as I know—and I may be wrong—this is the only journal named for actual humans.
The paper is about a small jumping spider (5 mm, or about 0.2 inches) from New South Wales, a new species named and described as Jotus remus. It’s like other species in the genus except for one feature: on its third leg—metatarsus and tarsus, to be exact—males but not females have a “paddle” made up of long setae (bristles). Here’s a male of J. remus compared to a congeneric species J. auripes (all figures from the paper):
Here’s an enlargement of the “paddles”:
Females of J. remus don’t have paddles; that’s a clue that these structures are somehow involved in sexual reproduction. Note also, in the photo below, that the females lack the distinctive black-and-white markings of males: this color dimorphism is another clue that females are choosing males in this species:
Now what on earth are these paddles for? Others have speculated that they help the spider “parachute” or grab onto vegetation when they’re jumping, and that might be true, but other species in the genus don’t have the structures. Further, female J. remus don’t have them, either, and if they evolved as aids to jumping or grasping vegetation, they would. Sexually dimorphic structures like the paddles probably evolved, at least initially, as a reproductive aid. That prediction is borne out by the authors’ observations of these spiders in the wild.
Here’s what a female sees when she’s sitting on a leaf:
Yep, the males crawl on the side of the leaf or stem opposite to where the females sit, waving their paddles over the edge to attract her attention. That’s what you see above. Why do they do this?
And here’s the amazing part: the males apparently do this to tire out the female so she’s quiescent when he finally jumps her and copulates with her. In other words, he’s wearing her out so he can mate with her without being eaten post copulo. These paddle displays can go on for hours before the male finally tries to mate.
It turns out that the female, perhaps thinking that the waving paddle is prey, keeps attacking it as the male waves it from side to side, and from different positions underneath the leaf. (Salticids have terrific vision.)
The male also has another behavior: he sits under a leaf and vibrates his whole body, almost certainly to alert the female that something is up—perhaps the presence of prey.
After a long bout of displaying his paddle and making the female attack it, she finally gets worn out. The males then does a characteristic display, performing “two very rapid and vigorous paddle strokes,” and then jumps on the female and copulates with her—an act that takes about 1.2 seconds. You’ll see that in the video below.
Why the final “double wave” before mating ? We don’t know, but the authors suggest that it’s either a way to let the exhausted female know that a mating is imminent, or to “test” her to see if she’s ready, as indicated by her failure to attack.
Here’s a mating: males hold females tightly with their rear legs; and remember, spiders mate not by putting their genitals together, but by males transferring sperm to their pedipalps (appendages on the head), and then inserting the sperm into the female with these structures. On the right you can see the male about to put his pedipalps into the female’s genitalia:
I was lucky enough to find a video on YouTube (below) that shows most of the behaviors described above. Do note the speed of copulation and how fast the male gets away afterward, chased by the female. I suspect a lot of this behavior occurs because without being tired, the female would attack the male, killing him before he had a chance to pass on his genes. Notice, too, the “double wave” at about 3:25, right before the mating:
One question is pressing: how did this evolve? It would seem that the incipient stages of the paddle would be of no use to the spider unless the male’s already using them to wave at the female. That is, how could the whole structure-and-display pantomime get off the ground given that without a paddle, the behavior won’t work, and without the behavior, the paddle is of no advantage?
I suspect, in fact, that the arm-waving came before the paddle, for a female could still attack an unornamented arm. Then any further elaboration of that arm—i.e., the paddle—would increase its visibility and efficacy. That’s just a speculation, of course, but it would be interesting to see if the relatives of this species who lack paddles do any arm-waving before mating.
At any rate, this kind of behavior is one of the reasons I became a biologist. The ways of nature—especially the ways that animals have evolved to perform the only evolutionary task they have, to pass on their genes—are multifarious and wonderful. Who could guess that something like this would evolve? And think what other wonderful structures and behaviors lie undiscovered in the 5 million or so species that are yet undescribed?
_______
Otto, J. C. and D. E. Hill. 2016. Males of a new species of Jotus from Australia wave a paddle-shaped lure to solicit nearby females (Araneae: Salticidae” Euophryini). Peckhamia 133.1: 1-39
Re the journal title, what about Wilhelm Roux’s Developmental Archives? (They changed the title a while back).
Cool post! Cool spiders!
MC
I knew I’d miss at least one journal. BUT, the whole journal isn’t his name!
Basteria, journal of the Netherlands Malacological Society, named after Job Baster, 18th-century naturalist
Brimleyana, former journal of the North Carolina State Museum of Natural History, named after early 20th century entomologist Clement Samuel Brimley
Zitteliana, journal of the Bavarian state museum of paleontology and geology, named after 19th-century paleontologist Karl Alfred von Zittel.
I think there are a lot more, that’s just off the top of my head. Peckhamia might be unique in being named after a married couple.
Well, I guess I was dead wrong. Error acknowledged.
Karstenia is the journal of the Finnish Mycological Society (is dedicated to P. A. Karsten (1834–1917)
http://karstenia.fi/
Copeia– journal of the American Society of Ichthyologists and Herpetologists, named for the famed paleontologist and neo-Lamarckian, Edward Drinker Cope.
Brenesia– journal of the Museuo Nacional de Costa Rica, named for the botanist Alberto Brenes
Although the journal is “extinct,” Brimleyana, from the North Carolina State Museum, was named for the Brimley Brothers, pioneer North Carolina naturalists.
Darn, I knew someone would bring up Copeia before I got here. Did Cope ever get designated as the lectotype for Homo sapiens?
Adding to the total:
Raffles Bulletin of Zoology
Zoological Journal of the Linnean Society of London.
(And Biological Journal of the Linnean Society of London, too.)
Best of all, there is a journal titled Darwiniana, but it’s published in Spanish, not English.
There are many such journals in botany: Lankesteriana, Richardsoniana, and Fieldiana are just a few that come to mind.
oops, “Richardiana” not “Richardsoniana”.
Stretching a little further, there was Senckenbergiana Lethaea (which sadly changed it’s name in 2009 to the more pedestrian “Palaeobiodiversity and Palaeoenvironments”) and was named “for the physician, naturalist, botanist and philanthropist Johann Christian Senckenberg (1707–1772).” (From Wikipedia.)
There’s something nagging at the back of my mind telling me that I know at least one other but …
Good little brain cell! Watsonia, “named after the eighteenth-century British botantist Hewett Watson.”
A lot of male spiders leg wave so I am sure that came first. Also crabs do it… signal selection!
Yes! I remember those crabs.
Seduction by hypnosis 🙂
Or seduction by perseverance.
I’m kind of surprised that she doesn’t just jump on the limb and try and inject it with digestion enzymes (or maybe she does, I haven’t watched the video).
The action of watching a prey animal move around until you’re too tired to move yourself, without either pouncing or just ignoring it seems…nonadaptational.
Why does she not attack the lure? You have to take into account the limitations of the visual system in salticids. They target with their big anterior eyes, which have telephoto-like optics: excellent resolution but very limited angular view. They seem to take several seconds to fill in the target area, in general tracking a prey item until it’s still before pouncing. So the male’s trick is to keep moving the lure before the female can get a bead on it. I’d guess a lot of the reported fatigue in the female is in the focusing muscles — at the end of this she may be too bleary-eyed to fend off or polish off her suitor.
That might be correct. The reason I mentioned “attacks” is that the authors of the paper assert this. So I was a bit puzzled when, in the video, the female simply eyes the lure.
The most likely answer is that the males are Madonna fans.
> It’s an experiment to see if I get more than ten comments on a science post.
I think that sentence screws up your methodology, professor 😉
On a serious note: I read this post and found it very fascinating, but apart from that, I can’t think of much to say, and wouldn’t comment under normal circumstances. I guess (and have some seen stating so much) it’s the same for many of my co-readers here.
I have a suggestion for a proper experiment – don’t know if it’s technically feasible though: Put all longer posts below a fold for a week or so, so they need to be opened separately, and compare views, instead of comments. Maybe your public’s interest in proper science is not in such a dismal state after all.
I don’t like to use folds as they’re not only an interruption on the computer, but are, I’m told, a pain in the butt to use on phones and other mobile devices.
Many science (and cat, and boot, and food) posts fall under this category for me. I read and enjoy them, but they’re not the sort of article I necessarily want to add a comment on.
So I guess my thought to Jerry would be: pay more attention to web site hits than comment numbers. Hits are probably a better proxy measure of viewership than # of comments. If you post an article and get few comments but your view numbers for that day are high, that means we’re reading but staying mum about it. 🙂
Yeah. I read this and found it fascinating, but wouldn’t normally comment because I have nothing to add to the discussion.
I guess on this one I could have written about tiring out cats by waving things at them/playing with them, which is what this reminded me of.
It reminded me of:
“Will you go out with me?” “No!”
“Will you go out with me?” “No!”
“Will you go out with me?” “No!”
[many requests later]
“Will you go out with me?” “Oh for goodness’ sake. Yes I will go out with you, once, if you’ll just stop asking!”
Ha ha! Yeah, that too.
Bit of a lesson there about going out with guys who won’t take “no” for an answer though – the end of the night might have anasty ssurprise.
My lesson from the spider is that my dating requests will succeed more often if I just wear big fluffy mittens 🙂
😀
I don’t comment on the science posts because I have nothing pertinent to say–other than that they are fascinating and that I always learn something. Now that I’ve long since done my ‘Darwinian duty,’ and can reflect upon human sexual love without too much pain or anxiety, I begin to understand more fully why senior members of Homo sapiens are either vestigial or parasitical. Well, at least we weren’t killed right in the act of copulation.
It would seem that a display to trigger the early stages of predation would be a very dangerous way to pass on ones’ genes. But watching the video gives the impression that the male is careful not to entice her too much.
It might be related to peacock spiders which have turned the whole ‘please don’t eat me’ thing into an impressive show, including waving ornamented second or third legs about and drumming with their pedipalps. Jurgen Otto has a Flickr account full of them, including an album of Jotus remus photos- https://www.flickr.com/photos/59431731@N05/albums
that is interesting. There are several species there that wave bushy 3rd legs, and so what we are seeing here can be a variation on an ancestral strategy.
I find these posts fascinating and love reading them (my education has sadly lacked in biology to which these posts thankfully address) but, like Robert Seidel, I don’t feel I can offer anything of value in a comment.
Here’s your 10
How common is mate-eating in other carnivorous groups? I can think of preying mantises, but how about:
Fishes?
Frogs and other amphibians?
Reptiles?
Birds?
Mammals?
Marine invertebrates in both arthropods and non-arthropod groups?
Unless parental care or some other cooperative behavior is involved, why not a more general practice of eating the male just after he gives up his seed?
(Commenting on science posts is more work–I have to think of something substantive to say, and then I have to decide if it is too naive a comment to post. I often delete posts before posting for this reason. Today I throw caution to the wind.)
“why not a more general practice of eating the male just after he gives up his seed?”
I suspect the answer is this: Insects and spiders are opportunistic and only a small number of them will even mate once in their lifetimes. So, loss of a male after mating will cause little difference in the gene pool.
On the other hand, more complex animals often do mate more than once, so males that stay alive contribute more to the gene pool than those who don’t.
OK, that answers the question I had – how does this behavior evolve? Why doesn’t the female allow copulation more easily. I can see there is selective pressure for diner for one here, since the female can channel the calories into here maternal duties. So, why does the male go to such lengths to evade becoming food? Doesn’t he want to support his family? What a bum!
Jay — Many “less-complex” animals can, and will, mate numerous times in both sexes; conversely, some darn-complex animals [cephalopods, salmon,marsupial mice] have a very compressed mating period after which they die.
Salticids probably live for one breeding season, but the mating period may be pretty long, with opportunities for males surviving one successful pseudocopulation to find additional mates. [I’m no expert here, but the common local salticids seem to reach adult size early in the season and then stick around for months.] So there’s likely to be diverging selective pressure: males will profit by getting away if the probability of their finding another mate is not exceeded by increasing clutch size in a well-nourished mate. Assuming that the male will not attack the female — she can always profit from another meal.
So why don’ we see nuptial male sacrifice in vertebrates? Probably because it’s too costly — vertebrate predators generally don’t risk attacks on something that’s very likely to damage them.
I’m trying to mind my “R”s and “k”s. Or trying to remember which strategy goes by which uninformative notation.
Some organisms have lots of offspring, in which they invest very little (small eggs, little parental involvement) [cue video of coral reef spawning, or wind blowing through grass] ; others have far fewer offspring, but invest far more per offspring [cue video of mother elephant facing down a pride of lions wanting her calf].
Obviously the strategies are ends of a continuum. But population genetics can chow down on models like that and lead to lots of nice statistics printouts for smacking creationists round the head with. And other, more useful outcomes too.
So there’s really three ways to think about that question: how did the behavior (mate-eating) crop up, how did it propagate through the population, and why does it stick around after propagation.
I would guess that the behavior could crop up in all species – insects, birds, mammals, anything.
I would guess that it most successfully propagates through species that produce many offspring per mating and have relatively few matings. Think of the limiting case of one offspring/mating: the species would go extinct! Or on the other extreme, the limiting case of one mating per animal: here it really doesn’t matter what happens to either parent after the babies can take care of themselves. In fact I believe there’s a species of spider where the momma sits and allows herself to be eaten by her offspring, which would be an example of this sort of principle in action. So, for propagation, we’re likely to see mate- (and parent-) eating in things like insects and spiders and maybe fish, but not birds and mammals or generally species that rely on a larger number of matings each of which produce a smaller number of offspring.
Now, why does it stick around? Well because mutation can be slow. I expect there are “arms races” going on in all species where this behavior occurs, with adaptations which allow males to not be eaten propagating through the population in counterpoint to adaptations which increase the females’ tendency to eat them. In the case of this jumping spider, we’re just seeing a fairly spectacular middle point in the arms race.
And I thought human sexuality was complicated.
Should we replace the Infinite Monkey Cage and the whole of the Shakespeare compendium with a rather more compact experiment involving lots of jumping spiders, some very small typewriters, and Shakespeares love sonnets?
That would be quite interesting and – considering the achievements of nanotechnology – also possible. At secondary school I thought Shakespeare was boring because most people are so snobby about him. Little did I know what a sexual deviant he was and that the English teachers were actually me and my schoolmates’ allies. I say teachers and not teacher, because 4 English teachers gave up within 1 year. That’s how horrible we were as schoolchildren.
The really comical thing about Shakespeare at school for me was that we weren’t allowed to be shown any films (well, the school had A video player, but normally it was film) of the plays before spending two years ploughing through JC (Not the “I wish to complain about a purchase I made not one hour ago from this very boutique!” ; “Sorry, we’re closed.” version, the “Infamy, infamy, they’ve all got it in for me!” one.)
If we’d actually seen how it was meant to be seen, we might have given half a flying flatulence about it.
(We only went through 2 English teachers. We were little darlings, obviously.)
OK, so Jerry got his >10 comments.
His paddle-waving was successful 😉
cr
I read and like the science articles, with or without clickbait titles. I’m not really fond of spiders, but this one is fascinating.
Same here, I read the science articles and enjoy them very much, but I am not versed well enough to dare commenting, though I like to show the ones about spiders to my wife; they freak her out and I get a good laugh.
It’s all good fun, please do not think I’m a bad husband. : )
A detail that I find surprising in this is that the male seems to gauge the reactions of the female, changing his behavior based on what she seems to be seeing and thinking – so to avoid a premature attack.
We accept that animals with large brains can determine what is on the minds’ of other members of their group, and to understand what another is seeing. This gets into the heady area of ‘theory of mind’. But here it looks like a little spider has a kind of understanding of what is on the mind of another spider, and it reacts accordingly to further manipulate her.
That is interesting. This is the same family of spiders that surprised researchers with their abilities to figure out complex routes to distant prey and then follow the planned complex route taking a relatively long time, and during which the prey is not visible to the spider until it reaches it.
At the time this behavior was discovered, then current modeling showed that the computational problem solving necessary to do that was not possible for a brain of the size that the spiders have. It led to research on how to solve such problems with much less computing resources.
Similar to that, perhaps useful degrees of modeling other organisms behavior does not take as much brain power as we currently suppose.
Reminds me of how humans can behave. There are some pretty amazing losers out there who simply wave their arms around and some women just fall at their feet, memorized. Is this what rock guitarists do?
Sometimes not only their arms, but other body parts as well. Likewise, such behaviour can be very exhausting and tiresome to female humans.
“She was memorized by the intense gaze of his jet black eyes and slow, intricate dance of his delicate hands.”
Others in the room were mesmerized.
I shouldn’t have mentioned the Infinite Monkey Cage, should I?
Sub
And of course there is selective pressure on the female to remain gullible and NOT to develop a ‘defense’ against this behavior, those that ‘fall for’ it are the ones who contribute to the next generation.
The male spider is also expending energy in order to exhaust the female according to this theory. A test of the theory would be to compare how much energy each of them uses up and how exhausted each of them becomes during this dance.
Ok, but it may not be about physical exhaustion. It could as well be about sensory acclimation. By stimulating her senses in this way, her threshold for noticing the stimulus will eventually decrease b/c that is what nervous systems do — they stop firing after a prolonged stimulus.
This is why you are not at this time feeling your socks.
… compared to the energy investments in, for example, providing a “nuptial gift”.
This appears categorically similar to other mating behaviors by salticidae: distracting females with fancy jazz hands. My guess is that this third pair of legs is less vital for gripping the underside of a leaf, and those males with puffier feett(?) tended to better attract the attention of more females. These are also, it seems, the same legs used to grip the female during copulation and these extra long setae may assist in this action, putting double the environmental pressure on developing this phenotype.
When you post the results of your experiment, the title should be:
“Evolutionary Scientist discovers this one simple trick to get more comments on your science posts. Creationists are nervous.”
I’ve always been quite fascinated with spider mating rituals. There are some medium sized orb weavers that usually set up a web or two outside my study window in the late summer here in sunny Portland, OR. The males (this species has *big* pedipalps), comes to the edge of the web and starts plucking the strands. The resident female darts toward the disturbance, but stops when the motion stops. This is repeated, often for 30 minutes, before the male ventures onto the web. There is then a face to face encounter where the male seems to push the female’s cephalothorax skyward while both members of the pair rapidly flail their legs. The male looks like he’s punching the female in the abdomen with boxing gloves during this display. This goes on for several seconds before the male retreats. He first backs away, plucking the web, then turns tail and runs. Sometimes, he is pursued, most times, not; I never saw the female catch a male. The same male will mate with the female two or three times before wandering off.
My question: do males then go on to mate with more females? I assume so, otherwise why go to all the bother not only to avoid being eaten but also to escape? Certainly preventing female predation *before* mating is necessary, but, in this species anyway (sorry I don’t have the ID), the males don’t stay for dinner.
Female spider: Not now honey, I’m too tired.
Male spider: Yeah, I know.
I’m confused. You said that the black and white stripes are a sign that the females choose the males, but based on the behavior it seems to me that the males are choosing the females, who don’t have much say in the matter. Is this a contradiction or am I missing something?
There are a few explanations for sexual dimorphism other than sexual selection. The one I think of right now is niche partitioning: male and female differ in morphology because they exploit different food sources and thus avoid competition for resources.
Of course that isn’t applicable in the current case, but if you google “sexually dimorphic niche partitioning” you get a great many references.
Another thing to keep in mind is that sexual dimorphism is not necessarily related to female choice; sometimes it is a result of selection to intimidate other males.
Any idea if it would be possible to estimate how much of the nervous system of these creatures is used by this? (I know that brainparts have overlaps, so this is hard, but …)
So… it’s a “Hit and run” kind of thing?
Love all the science posts!
Or is Jerry is sciencing a love post? 🙂
I notice the male seems to vary his waving pattern and rate of movement of the paddle. About when I was getting bored watching, he altered the motion subtly and my attention increased. After a few changes I was hooked and wanted to see what new twist or jab he would come up with. It was as if he sensed she might be getting board and wanted to keep her engaged.
Just piling on with the journals-named-after- people:
Adansonia – for Michel Adanson, the French naturalist and explorer.
Allertonia is a series of occasional papers published by the National Tropical Botanical Garden which was originally created by Robert Allerton and John Gregg Allerton.
Arnoldia, the quarterly magazine of the Arnold Arboretum, established under the will of James Arnold.
Baileya is a scientific journal of horticultural taxonomy, was established in 1953, but is currently inactive. Its name honors the late Liberty Hyde Bailey.
I’m guessing Blumea, Persoonia, and Gorteria (Dutch botanical journals) are all named for people.
Blyttia a journal published by the Norwegian Botanical Association is named after the Norwegian botanists Matthias Numsen Blytt and his son Axel Gudbrand Blytt.
Brittonia – journal of the New York Botanic Garden, presumably named for botanist Nathaniel Lord Britton.
Not even out of the B’s yet! This seems to be a particularly popular way of naming botanical journals.
Hi Jerry, thanks for this great article, I loved reading it and hearing your thoughts. I am one of the two authors of the paper in which this discovery was documented. Unfortunately the New Scientist article which you obviously read twisted the facts a bit. This behaviour is not intended to tire out the female. I watched it over days and females that attacked the male never mated, no matter how tired they may have been of chasing the lure. When females mated, it was within minutes of the male playing his game. These females were virgins and they were obviously interested in mating. Instead of attacking the paddle they almost instantly became calm when seeing it, something the male must have sensed and taken as cue. So it seems that what this behaviour is about is to establish whether a females is receptive and willing to mate or not. I did point the error out to the New Scientist author and hopefully he corrects it
Thanks for the most interesting facts!
That certainly helps. Thanks.
And thanks to you and your comrades for completing this fine and fun bit of research.
Way cool. Nuff said.
What a cute spider but I think calling them “crazy” is a micro aggression against spiders
When you’re down at 2 or 3 mm, a micro aggression is about all you can take.
Prof CC has been out-clickbaited – how’s this for a headline:
Spider has sex, then chews off own genitals
https://www.newscientist.com/article/dn26812-zoologger-spider-has-sex-then-chews-off-own-genitals/
(I’ve been waiting ages for an excuse to link that, not least because it contains the classic phrase:
But then, she does try to eat the male, so a lasting relationship is hardly the first thing on either spider’s mind.
😉
cr
Regarding sexual selection, have you seen the new paper in PLOS ONE:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0144672
The author suggests that Darwin was wrong, females don’t do the choosing. Here’s a review in NewsWise for science writers:
Mating Behaviour in the Natural World Contradicts Darwin’s Idea That Females Make the Decisions, Researchers Find
http://www.newswise.com/articles/mating-behaviour-in-the-natural-world-contradicts-darwin-s-idea-that-females-make-the-decisions-researchers-find
And they did their work on Drosophila. I’d be interested in your take on this.
Regards
Bill Barklow