Ever felt like you’re removing more spiders from your home in summer compared to the rest of the year? Our bug expert Phil Sirvid explains why spiders are so prevalent in summer, and what kinds commonly turn up in Wellingtonian’s homes.
The black-headed flax jumping spider
While spider numbers in general are up during the warmer months, for me as a Wellingtonian, the real ‘summer spider’ is the black-headed flax jumping spider (scientific name Trite planiceps) as this time of year is when they are most obvious.
It’s a native species, and as the name suggests these spiders jump on their prey to catch it.
Unlike most spiders, they have very good eyesight – it would be pretty tough to be able to leap on prey if they didn’t!
They’ve also been known to respond to mirrors if held 30cm or less away – they can also be quite interesting to watch when they are hunting flies.
While they can bite, they are not considered dangerous to people, although they may sometimes cause a start when they jump on someone unexpectedly.
The abundance of bugs
Otherwise, the summer months are a time where we expect to see more spiders in general, which of course mirrors the rise in insect numbers (and thus the food supply) at the same time.
Many spiders will have overwintered as smaller juveniles or as eggs. They might have been less obvious in the cooler seasons, but they were still there.
In summer these spiders will grow, mature and become more active and obvious.
Overwintering spiders might also get a new generation going in spring or summer, further adding to numbers.
Male spiders
One thing people might see will be more male spiders, and they will often see them indoors.
This is noticeable throughout summer, but especially so in late summer and early autumn.
Once a male spider reaches full maturity, he abandons any home he might have had and is only interested in finding females of his own kind to mate with.
An adult male spider can be recognised by looking at its pedipalps.
In females and young spider (including young males), these look like a pair of miniature legs located between the front pair of walking legs. However, in adult male spiders the pedipalps are tipped with bulbous structures that are unique to each species and these are used to inseminate females.
If you see a spider with something like a boxing glove, an ice cream scoop or some other odd shape at the end of its pedipalps, chances are you have a male.
As male spiders wander, they may stray inside where they generally won’t find what they are after.
I’ve returned several male spiders to the great outdoors myself this past week.
Beyond basic self-preservation, mating is pretty much all they are concerned about and they will spend the last days of their short lives looking for females.
Other common summer spiders
Other species that people are asking me about at the moment include vagrant spiders, nursery web spiders, and I’m also seeing a number of sheetweb spider males.
Spiders in our Bug Lab exhibition
Whether they’re crawling in your window looking for love, or making their home in your wing mirror, spiders have some incredible abilities.
In our Bug Lab exhibition you can see how all sorts of surprising things are being made with spider silk, which has antibiotic properties and gram for gram is stronger than steel.
You can also learn how venom from spiders and other bugs might lead to new medicines and other useful things.
Bug Lab is on at Te Papa until Easter.