Subject: white spotted spider beetle
Location: Nova Scotia
November 26, 2012 12:29 pm
I do not see this bug species on your site. I have a problem with it. It recently appeared from a void in the BR, under the vanity. Quickly becoming a pest I have to deal with. Crawling bugs are controlable but flying is a problem. Has been identified; sharing photos; hope they come thru. I have seen egg, partially developed, crawling and flying. Is not in my kitchen or food. Does not bite, but the flying ones burn like a no-see-um if they light on me. I do not know how it got here, must have come on store products. Could almost miss the flyers for fruit flies. How prevalent are they in Canada?
Signature: Bugged

Whitemarked Spider Beetles

Dear Bugged,
Since we did not know this species, we looked it up on BugGuide and believe you are speaking of the Whitemarked Spider Beetle,
Ptinus fur.  BugGuide indicates it was:  “introduced to NA before 1870.”  BugGuide reports sightings in Ontario and the United States across the border.  Thank you for adding to our archive of Household Pests.

Whitemarked Spider Beetles

Is that really a photo of the egg?

Whitemarked Spider Beetle Egg, we suppose.

These photos surprised me when I enlarged them as it looks like a spec on the sticky paper of the monitor box I photographed. It is certainly some stage of development. I thought it had started to change color on one end?  Have not seen any nests or fuzzy pupae they describe in some writing and the “fur” is not evident without magnification, they are very small to start.  Am certain these are the developing ones.  In the further monitoring I checked yesterday there is a fully developed winged one, looks much like a common small housefly, plus there is the first I have seen that shows the spotted body really well (female?).  I will try and get a decent photo of that box.  I got the ID through Orkin pest control who contacted their lead entomologist at their Quality Control.
“It is white marked spider beetle. There are differences between females and males looks. The white patch may not always be the same.”
The worst of this specific one for control is that it flies.  I am not sure how it arrived, but I did buy a new sisal cat scratch post from a pet store in Oct.. and it sat on the floor on the opposite side of the bathroom wall, BR being where they emerged.  I have no carpets.  They are not in the kitchen, BdR or living room except a rare crawling one killed early on.  But they have moved into the basement and I see very few in the BR now.
I was surprised to find that of the ones caught on paper first (in the pictures I sent) and placed in a ziplock bag, some still had faint life a week later.  They are extremely hardy.

Update from Carol January 3, 3013
Hi Daniel:  Sorry to be so long getting this done.  In 1271 note there is an egg in the 4 o’clock position.  It is quite round and black when the picture is enlarged and in Picasa3 which I use I tried to correct the blur and it just went quite black so I left it untouched.  Enlargement is not as clear as it should be but it is the camera.
Would like to say these beetles seem to go on to become some version of a small fly from what I can tell.  There is no evidence they came on the cat post I mentioned.  I believe myself they either came on clothes from the line stored under the cabinet or under the siding and followed the double beam across the house.  I did see ants going there during our very hot dry August and got them but this could be from the same area.  No other explanation comes to mind.
I have had pest control once a few weeks ago.  They are gone now from upstairs, but not gone entirely from the basement and PC will come again to redo.  I am hopefully optimistic they will be eradicated but it is a real problem as they are so minute and even microscopic as some of this I could not see until photographed… more that I ever wanted to know about them!
Beetles Identification Guide
Ptinus fur (Linnaeus)
whitemarked spider beetle
ptine bigarré
Diagnosis: The species is distinguished from the other Ptinus included here in
having 2 tufts of setae on the pronotal disc, with the surface between the tufts
dull, punctured, and granulated.
Sexual dimorphism: Males (Fig. 224) have the elytra subparallel-sided, the eyes
larger and more convex, the antennae longer (10th segment about five times as
long as wide), the tufts of setae on the pronotal disc less defined, and the
metasternum longer and convex. Females (Fig. 225) have the elytra subobovate,
the eyes smaller and less convex, the antennae shorter (10th segment about
twice as long as wide), the tufts of setae on the pronotal disc more defined, and
the metasternum shorter and flat.
Distribution: Reported from Europe, North Africa, Asia, New Zealand, and
North America, where it was introduced before 1870. In Canada the species has
been collected in all provinces.
Economic importance: In Canada, this species is found mainly in warehouses
and dwellings, less frequently in museums, granaries, and grain elevators. It is
one of the most commonly reported ptinids in British Columbia.
Ptinus ocellus Brown (synonym: P. tectus auct.)
Australian spider beetle
ptine ocellé
Fig. 224 Ptinus fur (Linnaeus); male. Scale = 0.5 mm.
Fig. 225 Ptinus fur (Linnaeus); female. Scale = 0.5 mm.


Location: Canada

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