Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Clickable Guide
Moths Butterflies Flies Caterpillars Flies Dragonflies Flies Mantids Cockroaches Bees and Wasps Walkingsticks Earwigs Ants Termites Hoppers and Kin Hoppers and Kin Beetles True Bugs Fleas Grasshoppers and Kin Ticks Spiders Scorpions Centipedes Millipedes

Upcoming Events

See Moth submissions from National Moth Week 2023

Photos of insects and people from the 2022 BugGuide gathering in New Mexico, July 20-24

Photos of insects and people from the Spring 2021 gathering in Louisiana, April 28-May 2

Photos of insects and people from the 2019 gathering in Louisiana, July 25-27

Photos of insects and people from the 2018 gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Previous events

Adult female - Phylloneta impressa - female

Adult female - Phylloneta impressa - Female
Whitecourt, Alberta, Canada
July 22, 2010
Size: BL ~ 4-5 mm
I'm putting this under T. impressum for now, based on the general abdominal pattern, size, web type with the typical cup-like retreat formed out of bits of vegetation and remains of prey, and the blue egg sac, all consistent with others of this species I've found in my area. The colors are different on this specimen, though. Compare with the more "usual" specimen I'm used to seeing:

These spiders are interesting in that the young stay with the mother through several molts and often for many weeks after hatching. She lets them eat from prey she captures during this time. The female doesn't live long after the spiderlings hatch, maybe a couple of weeks, and the young remain in her web after she has died. I have found juveniles almost as large as the mother, still in her web, a few weeks after she has died. No evidence yet that they make a meal of her.*

It will be a while before I can verify the species ID on this one by the epigyne. I have to let the babies hatch first so that nature can take its course.

The web was constructed in the dead outer twigs of a raspberry bush, about 2 feet off the ground. She will add to and enlarge her retreat with the remains of future prey, and it will soon be large enough to shelter her upcoming brood. I took the picture from underneath the spider, looking straight up.

[* - After posting these remarks, a female I had in the lab was eaten by her spiderlings. They'd been in her web for a few weeks, and sharing her food. Then, one day they basically swarmed over her, and though she struggled they were overwhelming and she soon died and was eaten. The spiderlings had been fed regularly before they did this, so why they suddenly turned on their mother is a mystery. Of the maternal webs I've found in the wild, and visited regularly over a period of several weeks in each case, the young usually molted through several instars while the mother was still alive, but I noticed no hostility from one to the other.]

Should the page for Theridion impressum
be deleted?

I thought I'd leave it for a while so that anyone looking for T. impressum will find a link there to the new name and guide page.

I don't know if there is a better way to do this, but this (maintaining the old page) is useful, otherwise links to the species become broken. I suppose the alternative is to maintain the same node number (the BG number) and then modify the taxonomic information as necessary? Perhaps that would be better? But is it possible? Or preferable?

In my own database I do both. In somecases a "page" remains, but is assigned "synonym" status (changes heading color, among other things), so that one can click through from the synonym page to the current name. In other cases (e.g. a species is moved to another genus), I simply update the information on the current page and add the old genus name to the.. "old genus names list".

T. pictipes was also moved to Phylloneta
in 2008. I moved it here and I'm doing a little experiment to see what happens with the links. I'll let you know what I find.

Edit ~ I followed every link that the search brought up. As long as the link was to the species images page it brought me to the new Phylloneta page. However, if it was linked to the genus page.. of course that still take the person to Theridion. None of the links were 'broken'.



Wow -
great photo and natural history information, John!

The amount of black pigment in this holarctic species also seems to vary quite a bit. Nice observations.


Quite "impressive"
indeed! Lovely

Comment viewing options
Select your preferred way to display the comments and click 'Save settings' to activate your changes.