I was watering my hydrangea when I noticed that one of the leaves was tubular. I immediately suspected a caterpillar and instinctively pinched the leaf from its stem.
“Shoot. Why did you do that?”
I’d recently done the same while checking another plant, only to realize the tube held the larva of a Long-tailed Skipper, one of my favorite butterflies. Once I realized, I removed the swollen, sluggish caterpillar and returned it to the plant; and was pleased to discover that, within 48 hours, it had wrapped itself once more.
Had I disturbed another Long-tail?
I held the leaf in my hand and saw something moving within. Gently I separated the leaf’s edges, which had been secured with a sticky webbing. Inside was a small spider, roughly 5 mm in length. A beneficial.
“Sorry little one.”
I laid the leaf on the plant, close to where it had been clipped. Then went for my camera as the spider immediately worked at repairing the damage.
In a short time, it was hidden once more. It even reattached the leaf to its branch using spider duct-tape.
Through the photos, I identified it as a Broad-faced Sac Spider (Trachelas tranquillus). Trachelas is a nocturnal spider that hunts by stalking or running after prey. It’s unusual, however, in that its also scavenges, consuming dead insects and deceased spiders.
During the day, Trachelas wraps itself in a leaf, hides between rocks, or secures itself among loose tree bark. These locations also serve as nurseries, where females lay 30-60 eggs and watch over youngsters. Spiderlings do not need to eat immediately after hatching and remain with their mother for roughly two weeks, at which time they undergo their first molt.
Sometimes Trachelas overwinters indoors. Although they are non-aggressive to humans, they will bite if squeezed or when defending nests. The bite feels like a bee sting, and may be sore for several days, but isn’t considered serious.
Next time I see a curled leaf, perhaps I can remember to resist the urge to pluck it and, instead, retrieve a magnifying glass, since there are many friendly guests hiding among my plantings.
Note that not all references were specifically about the Broad-faced Sac Spider. However, the various sac spiders seem to have similar life histories.
Broad-Faced Sac Spider – Trachelas tranquillus. Carnivora. Jun 14 2018.
Broad-faced Sac Spider (Trachelas tranquillus). SpiderIdentifications.
Spider Sunday: A Common “Indoor” Spider. Bug Eric. Nov 4 2012.
Sac or tube spiders, Family Clubionidae. Ednieuw.
Black-footed Yellow Sac (Cheiracanthium inclusum). SpiderIdentifications.