Spiders are both predators and prey and sometimes we see one in each role in the same, fatal, encounter.
The Daddy-longlegs (Pholcus sp.) in these photos lives quietly between my computer and the wall, waiting for anything edible to come by. (It is probably a direct descendant of this family, since there are always a few in the area.) Jumping spiders, on the other hand, are roving hunters and this little brown one (I thought it might be Servaea or Simaetha sp. but have been reliably informed it is a juvenile Hypoblemum) was on the prowl when it blundered into a strand or two of web.
That had just happened when, by pure chance, I reached around to plug in a camera lead and saw what was going on. The daddy-longlegs, outweighed two to one, took care to stay at a safe distance as it used those long legs to further entrap its prey in silk. The process took a couple of minutes and the jumping spider never even looked like getting away. When it was secure, the daddy-longlegs finally came down to sink its fangs into its victim.
Most of us, I think, automatically (and not always logically) choose sides in a conflict like this. If it’s between a lion and a deer, we tend to sympathise with the deer; if a kookaburra and a snake, we’re on the bird’s side. Cat and gecko? Bird and butterfly? Bird and spider? We don’t always side with the hunter, or with the hunted, or with the vertebrate against the invertebrate, or the mammal against the reptile. What do we think about spider vs spider? Or spider vs fly? More interestingly, perhaps, why do we think whatever we think?
The other ‘small death’ I saw yesterday was, in fact, spider vs fly: one of our larger jumping spiders, Mopsus mormon, had captured a soldier fly: