Chiracanthium mildei is also recognized by its behaviour. It is a formidable hunter of insects by night, resting in a bivouac during the day. A bivouac is similar in appearance to a moth cocoon often seen lying in a corner between ceiling and wall. The silken bivouac is also used as a nursery early summer. C.mildei reproduces once per year having an approximately one year life cycle in the Province of Ontario. Adults may overwinter indoors. It is a recently introduced species (c.1950) from south-central Europe. Outdoors, C.mildei  bivouacs in, especially,  fruiting grapes.  Outdoors, they commonly  occur around decking and porching, in high warm locations, as indoors.

The mobile, nocturnal behaviour of the black-footed spider leads to unfortunate interfaces with people. If pressed against the skin, naturally, it will bite to protect itself. The bite may awaken a sleeping person. If not, and the spider remains trapped against the skin, more than one bite may occur. An untreated bite wound often appears as a pimple at the centre of a small, inflamed halo within the first 24 to 48 hours. The centre eventually blackens as a scab, then sloughs off leaving a small ulceration. Depending on the sensitivity of the individual, the lesion may take anywhere from several weeks to several months or longer to clear up. The "pimple" should never be picked or squeezed. Clinical symptoms, in some cases, are nasty enough to warrant confusion with the bite of the Brown recluse (=violin spider) (Loxosceles sp.) (Gorham & Rheney 1968; Spielman & Levi 1970) which has a southern distribution in North America and is not indigenous to Ontario.

Suggestions on treating a black-footed spider bite¹

If the bite is immediately discovered at an extremity, apply a tourniquet. Wash the area from the bite centre outwards to prevent potentially smearing more venom into the wound. Then thoroughly wash with soap and water. Avoid using alcohol. Relax, avoiding activity or substances which speed up the heart rate. Apply a clean ice pack, alternating with clean astringent packs to draw out the venom (e.g. tea bags boiled in water, squeezed and applied tepid; sterile cotton pads moistened with witch hazel). Never pick or squeeze the lesion site. Not only may this damage local tissue causing secondary infection, it can aggravate spread of the poison, thereof, with potentially longterm damaging affects.

Also, attempt to collect the spider to facilitate its identification by an expert.

Suggestions for control of the black-footed spider inside the home

Learn to recognize the black-footed spider (see earlier text) so as not to confuse it with other spiders. Immerse grapes and other dense fruits and vegetables of the garden in water for several minutes before bringing them indoors. This will force bivouaced spiders to extricate themselves.

Indoors, the black-footed spider is easily collected from the bivouac during the day. If an inhabited bivouac is even slightly disturbed, the spider will drop out of it. Thus, press a deep, flexible container such as an empty margarine tub flat against the wall immediately below the bivouac, keeping the lid handy. Touch the bivouac. Act quickly in replacing the lid on the container because once the spider drops, it will move quick.   The container may be carried outdoors and the spider thrown.

Alternatively, the spider may be killed by placing the container into the freezer. Later, remove the container and, if desired, have the spider identified by an expert. For long term storage outside of the freezer, seal the specimen in a vial containing rubbing alcohol or 75% ethanol. Include a pencilled label inside of the vial indicating the date and place where the specimen was collected.

Black-footed spiders on the move or in bivouacs in hard to reach places may be sprayed with a mixture of soap and water: Fill a one litre plant mister with water almost to the top. Add one or two tablespoons of dish soap. Stir, test that the mixture feels slippery, and cap. You have just prepared the most effective contact insecticide possible. Results, on direct contact, are instantaneous.

It is not recommended to indiscriminately kill all spiders occurring in and around the home. They are effective natural enemies of insects. Many accidentally occur indoors where they would prefer to be outside. The American house spider, for instance, is a common cobweb spider, effectively traps both flying and crawling insects, and is incapable of biting man. It should be welcomed indoors.

REFERENCES

J. Richard Gorham and Theodore B. Rheney. 1968. Envenomation by the spiders Chiracanthium inclusum and Argiope aurantia: Observations on arachnidism in the United States. JAMA 206(9): 1958-1962.