Spiders that get eaten after sex are picky about mates. You don’t say


Feedback is New Scientist’s popular sideways look at the latest science and technology news. You can submit items you believe may amuse readers to Feedback by emailing feedback@newscientist.com
Problematic coupling
In a long-ago time (May), Feedback asked for examples of “no shit, Sherlock” – scientific studies spending an inordinate amount of time and effort to demonstrate something obvious. Reader Roger Erdem obliged, with evidence that injuries are more likely if you don’t rest long enough and that fiddly tasks take longer to perform.
However, Roger isn’t done, and continues to send examples of self-evident findings. While we wait for someone else to pick up the baton, here are two more. First, in June the journal Demography published a paper with the gloriously gossipy title “Sleeping with the enemy: Partners’ heterogamy by political preferences and union dissolution. Evidence from the United Kingdom”. Phys.org neatly summed this up: “Couples with opposing political views face higher risk of separation, study finds“.
Feedback is staggered that differences over politics could lead to strife in relationships. Whatever happened to judging prospective partners based solely on their looks and fashion sense?
Speaking of problematic coupling behaviours, Roger’s other obvious result is from 2016, when the journal PLoS One published a paper titled, “Coy males and seductive females in the sexually cannibalistic colonial spider, Cyrtophora citricola“. It’s about the relationship dynamics in a group-living spider species, whose females are prone to eat males after sex. The researchers found that the males were selective about their mates, favouring younger and well-fed females.
Or, as the headline on phys.org put it: “Male orb-weaving spiders cannibalized by females may be choosy about mating“.
With no apologies whatsoever, Feedback is going to be pedantic about this, because it isn’t quite as obvious as it seems. According to the researchers, males of solitary species might not be choosy at all. Such males might encounter females so rarely that they choose to risk postcoital decapitation regardless of their mate’s quality. Hence the focus on a social species, in which natural selection has favoured males that choose carefully before sacrificing their lives for sex.
Clearly, there is a great deal of “no shit, Sherlock” out there. Can anyone else find any other examples? Let’s not always see the same hands.
Fiction, disproved
As a long-time science fiction reader, Feedback appreciates the peculiar experience of reading an older story that can no longer be true. That is, a story that turns on a premise that used to be plausible, but which, given current knowledge, is either mildly daft or entirely impossible.
Sometimes this is just “predictions” that have now been surpassed by the passage of time. Blade Runner was released in 1982 and set in 2019. We are now six years beyond that date, and Feedback notes the continued absence of flying cars. However, we will concede the film was basically right about the awfulness of tech billionaires. And depending on whether you followed Star Trek or The Terminator, the late 1990s were supposed to be marked by either eugenically created superhumans or a nuclear war.
However, we want to highlight another phenomenon: that of a new scientific result seemingly obviating the entire premise of a story. For instance, The War of the Worlds has long been condemned to implausibility by the apparent lack of Martian animal life.
Something similar appears to have just happened to the Revelation Space books by Alastair Reynolds. Feedback would like to say right now that we still really like these books, and also that anyone who hasn’t read them should stop reading now, because the next paragraph spoils one of Reynolds’s biggest reveals.
The story turns on the fact that our galaxy is going to collide with the Andromeda galaxy in a few billion years. As a result, humanity comes under threat from a machine species called the Inhibitors, who aim to limit intelligent life in the galaxy until the crisis has passed.
Except that Nature Astronomy published a paper on 2 June with a blunt title: “No certainty of a Milky Way–Andromeda collision“. The researchers simulated the movements of all the galaxies in our local cluster and found that “uncertainties in the present positions, motions and masses of all galaxies leave room for drastically different outcomes”. As a result, they say, “the fate of our galaxy is still completely open”.
We encourage readers to tell us about other examples of recent discoveries that have undermined formerly plausible sci-fi premises.
More Gs
Over at newsletter London Centric, readers may read about “The real 5G conspiracy: How Londoners are being lied to about their phone signal“. This describes the common experience of “high levels of mobile phone coverage (as shown by the signal bars on your phone screen) but no functioning data download capacity”. Apparently, Londoners’ phones are telling them “they are connected to modern 5G mobile data networks”, but, in reality, they are “unknowingly stuck running their work and social lives over 4G”.
The journalists were tipped off to this by the creator of an app called SignalTracker. The article describes this man wandering around London “carrying five different mobile phones” to test the various networks.
So far, so late-period capitalism. However, reader Brian Darvell wishes to highlight the name of this cellphone detective: Martin Sims.
Got a story for Feedback?
You can send stories to Feedback by email at feedback@newscientist.com. Please include your home address. This week’s and past Feedbacks can be seen on our website.