Can you ID this indoor critter debris? to do with spiders or some other kind of creature? - Ask Extension
Today, when moving a small bookcase away from the wall in a finished outdoor cottage, which is used as storage in the winter, I discovered a large b...
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Can you ID this indoor critter debris? to do with spiders or some other kind of creature? #626695
Asked April 22, 2020, 8:00 PM EDT
Today, when moving a small bookcase away from the wall in a finished outdoor cottage, which is used as storage in the winter, I discovered a large black spider, many small spiders, and a number of white spider sacs attached to the bookcase, but accompanying this mess, was a large number of long dark squiggly things (photos attached) I also saw these squiggly things in another corner.
I had already disposed of the majority of the stuff behind the bookcase when I noticed the other, and decided to take a few pictures. One location was in an inner corner next to a closet, the other was immediately next to the door which enters into the cottage.
What on earth is it? Should I be concerned about it, and if so, what action should I take? I confess to being extremely creeped out! I would be extremely grateful for your input. Thank you.
A. L. Vernon
Multnomah County Oregon
Expert Response
Thank you for the image of the "dark squiggly things." They are millipedes. They are normally outdoors where they feed on decaying organic material.
When millipedes wander indoors, they generally die in short order because conditions area too dry for them. They don't damage anything indoors.
Looking at an image, it's difficult to know if the millipedes are dead or not.
Because so many bodies (dead or alive?) are present, it would be wise to investigate what sort of entry the millipedes used, such as structural cracks or damage, or via openings where utilities enter the cottage. The wall appears to be be incomplete. Perhaps the cottage needs the services of a handyman.
See "Centipedes and Millipedes" - http://ipm.ucanr.edu/PMG/PESTNOTES/pn7472.html
Thank you for your very quick response. None of them are moving, so I'm assuming that they are dead. The wall is not incomplete; one of the photos was taken immediately next to the door to the cottage, which I had opened for more light. The tiny cottage is a very old garage ( about 1930s) on a concrete slab, which was converted to a minuscule ADU (I use it mainly for storage, as I have no garage now). I know that bugs seem to be able to get into the tiniest of spaces, and once the door is closed, I am unaware of any other larger more obvious openings. As the small garage/ADU is flush with the ground/driveway, does this make it more likely to have these kind of critters? As it rains here so often, I'm sure the ground is wet underneath, and moisture was mentioned in the article you linked in your response.
I had initially wondered if they were connected to the multiple spiders behind the 3 foot tall bookcase I moved (immediately next to the front door), but perhaps this was a red herring. As I don't see any other obvious larger openings, should I be concerned about this as an infestation? Should I take any particular actions?
The space is mainly used in the warmer months (I have occasionally used this as a guest room in the summer), as the heating is insufficient for the winter (due to the previous owners choice of a inadequate wall heating unit) and tend to store garden furniture and other things during the colder months. This means it is not seeing much human activity during those colder months. Is there anything else I can do to discourage this kind of spider/millipede/other critter visitation?
Thank you for helping me out.
I had initially wondered if they were connected to the multiple spiders behind the 3 foot tall bookcase I moved (immediately next to the front door), but perhaps this was a red herring. As I don't see any other obvious larger openings, should I be concerned about this as an infestation? Should I take any particular actions?
The space is mainly used in the warmer months (I have occasionally used this as a guest room in the summer), as the heating is insufficient for the winter (due to the previous owners choice of a inadequate wall heating unit) and tend to store garden furniture and other things during the colder months. This means it is not seeing much human activity during those colder months. Is there anything else I can do to discourage this kind of spider/millipede/other critter visitation?
Thank you for helping me out.
Several points to consider:
- Structures on a slab provide easy access for a number of (unwanted) small inhabitants;
- Because all the millipedes are dead, their carcasses might have been behind the dresser for quite some time;
- Spiders tend to be opportunists; they set up webs where "food" is available.
- Since the garage is from the 1930s, it's likely similar to a friend's 100-year-old farm house; she remarked it's "leaky as a sieve" when it comes to cracks and crevices where critters might enter.
