Southern House Spiders in Texas

BugsInTheNews is a VIEWER-PARTICIPANT WEBSITE. This article by Jerry Cates, first published in January 1999, was revised last on 29 July 2012. © Bugsinthenews Vol. 01:01

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Southern house spider, male, as drawn in 1842 by Nicholas Marcellus Hentz

Southern house spider, male, as drawn in 1842 by Nicholas Marcellus Hentz

Southern house spider, male palps, as drawn in 1842 by Nicholas Marcellus Hentz

Southern house spider, male palps, as drawn in 1842 by Nicholas Marcellus Hentz

The southern house spider (Kukulcania hibernalis) was first described in 1842 by the French-American arachnologist Nicholas Marcellus Hentz, M. D.

In the 1875 book The Spiders of the United States, a collection of The Arachnological Writings of Nicholas Marcellus Hentz, M.D., he is quoted on this species in these words:

1. Filistata hibernalis. Deep mouse-colored, covered with fine short hair; cephalothorax darker; cheliceres small. Male, pale gray or livid; palpi excessively long, two middle eyes black, the others shining white.

Observations. It makes a tubular habitation of silk in crevices on old walls or rocks, throwing an irregular web which is spread on the wall or stone around the aperture. It comes out occasionally during the winter, but cold is apt to render it torpid, and it then remains several days in the same situation, moving slightly in the middle of the day. In walking, it uses its palpi like feet, and these organs are very long, particularly in the male. I saw one of this species change its skin in confinement. It had previously lost a leg by some accident, but after moulting it had a new one which had all its joints, only a little shorter than the natural size ; its cocoon is spherical.

Habitat. South Carolina on the sea-coast, North Alabama on the banks of the Tennessee. [length, 13.8 mm.; cephalothorax, 6.2 mm.; legs, 23, 19, 15.6, 20.6. Fernandina, Fla., Sept. 1, with cocoon of young. E. Palmer, j. n. k.]

Filistatidae: Southern House Spider (Kukulcania hibernalis); Male corpus; Central TX--1995

Filistatidae: Southern House Spider (Kukulcania hibernalis); Male cephalothorax; Central Texas --- 1995

Filistatidae: Southern House Spider (Kukulcania hibernalis); female cephalothorax; Brandon N Northeast TX--07.21.2008

Filistatidae: Southern House Spider (Kukulcania hibernalis); female cephalothorax; Brandon N., Northeast TX--07.21.2008

In The Common Spiders of the United States (Emerton 1902) the last page of the text is devoted to this spider, which was then classed in the genus Filistata. It was described it as

the most common house spider in the southern states, making webs in corners and on walls and fences.”

The body, Emerton pointed out, though only half an inch long, is provided with legs so long as to make the spider look much larger. The palpi are thick and as long as the cephalothorax.

The eyes are in one group, close together.”

Fig 93, p. 107: The Spider Book, by John Henry Comstock, published by Doubleday, Page & Company, N.Y., 1914

Figs. 276, 277, & 278: p. 290 of The Spider Book, by John Henry Comstock, published by Page, Doubleday & Company, N.Y., 1914

In The Spider Book (Comstock 1914) the palpi of the male is described and illustrated, in significant detail (pp. 107-8):

In Filistata hibernalis, which is a very common house spider in the South, is found the  most simple type of male palpus that I have ever seen among spiders. In the males of this species, the distal end of the last segment of the palpus, the tarsus, contains a coiled tube (fig. 93); this is the receptaculum seminis. The proximal portion of this tube is slightly enlarged and ends blindly; the distal end is slender and extends through a slender, twisted prolongation of the tarsus ending at its tip by an open mouth. The modified terminal portion of the tarsus, which contains the receptaculum seminis, is the genital bulb. By looking directly at the tip of the palpus, instead of at one side of it, it can be seen that the base of the bulb is situated in a cavity in the end of the main part of the palpus (fig. 93, a); this cavity is the alveolus (Menge ’66). The slender prolongation of the bulb, which contains the terminal portion of the receptaculum seminis is the embolus; the embolus is often termed the style.”

In this same book, Comstock later (pp. 290-298) describes the spiders in the genus Filistata in general. This genus included the southern house spider, Kukulcania hibernalis, until Lehtinen moved it to a separate genus in 1967, and Comstock’s remarks focus on the morphology and habits of this species. Selected portions of his text are reproduced below:

In (the family Filistatidae) the cephalothorax is oval, longer than broad. The eyes are massed in a small group, which is hardly wider than long: the anterior median eyes are dark in colour and round, the others are pearly white and oval or angular (Fig. 276). The chelicerae are smalland lack a lateral condyle; they are chelate, the short clawbeing apposed by a prolongation of the basal segment (Fig. 277). The palpus of the male is the most simple found among spiders.

The most important characteristics of (the genus Filistata) are given in the above description, to which may be added the following: The calamistrum is near the base of the fourth metatarsus and is very short (Fig. 278). In the adult male the calamistrum is wanting. The palpus of the male is comparatively simple in structure (here he reproduces his early drawing, shown in Fig. 93); it is described in detail on p. 108. The following is our only species:

Filistata (now Kukulcania) hibernalis (F. hi-ber-na’lis). — The larger individuals of this species (Fig. 279, not shown) measure from one-half to five eighths of an inch in length. The legs are long, especially the first pair, which are almost twice as long as the body. The color of the body is usually a dark brownish black without markings. But I collected many specimens under stones at Austin, Tex., that appeared velvety black in some lights, in other lights they bore a lead-coloured tinge.

These are sedentary spiders which live under stones, in crevices about buildings, and in other similar situations. The spiders themselves are rarely seen, except by the collector, but their webs are often very conspicuous, especially in the extreme south. These webs are frequently built upon the sides of buildings and are more or less circular in outline, surrounding the opening of the retreat of the spider…”

Much of the remainder of Comstock’s exposition on this spider describes how he made a box, in his lab, to serve as a retreat. In this way, he could observe how the species constructed its web. He learned that the spider would wait a few days before beginning its web, and would only work at night. Flies caught in the web would entice the spider from its retreat in the daytime, but only long enough for the fly to be carried back into the interior of the box. He then describes the nature of the web itself. He asserted, in the process, that four kinds of silk were used in the web, (1) a doubled supporting line that appears as a single thread , (2) the primary looped threads that form the axis of the hackled band, which are extremely elastic, (3) the secondary looped threads, supported by the primary looped threads, that form a regular series of loops, and (4) the viscid silk, forming an amorphous sheet that fills the spaces between the loops of the secondary threads.

Comstock’s fascination with the webbing produced by this spider has been shared by a multitude of arachnologists, then and now. The scientific papers listed at the foot of this article include several reports on cribellate silk and the webs cribellate spiders produce, often using the southern house spider as a prime example.

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When, in 1980, I first began collecting spiders for serious study, many of my clients — who by 1986 were scattered all over Texas — took to pickling the spiders they found for me to examine on my regular visits to their sites. Much of the time the spiders they pickled were male southern house spiders (Kukulcania hibernalis).

And, most of the time, they believed that the spiders they had collected were specimens of the brown recluse (Loxosceles reclusa), a spider whose bite is among the most feared of any spider found in North America.

On being presented with the pickled remains of a southern house spider, I’d conduct an immediate examination, using a portable microscope, inviting my host to take a look as well. We’d discuss the arrangement of the eyes, and the long, spindly pedipalps, until no doubt concerning the proper identification remained. Learning that these were not brown recluse spiders, but harmless crevice weavers, should have pleased them, but it did not. Instead, most were sadly disappointed. It dawned on me, eventually, that conquering a fierce arachnid of some repute had added excitement — not to mention bragging rights — to their lives. My contrary report had burst that bubble.

The southern house spider is quite large, in both genders, with a stout body and long, well-developed legs. It looks like it means business, capable of inflicting significant harm on any human that crosses its path. Perhaps that is part of the reason most people fear it. In truth, however, this spider’s demeanor is quite tame, and its bite is of no medical consequence whatever.

Filistatidae: Southern House Spider (Kukulcania hibernalis); frontal face; Central TX--c.1995

Filistatidae: Southern House Spider (Kukulcania hibernalis); frontal face; Central TX--c.1995

Southern house spider, eyes, as drawn in 1842 by Nicholas Marcellus Hentz

Southern house spider, eyes, as drawn in 1842 by Nicholas Marcellus Hentz

The Filistatidae family name is a hybrid comprised of two languages. The prefix, from the Latin word filum = “thread”, is conjoined with a Greek suffix, στατικος, pron. statikos, meaning “to cause to stand.”

It is believed that the French zoologist, Pierre André Latreille (1762 – 1833), who created the name in 1810, intended to describe “a spider standing on a thread” (Ubick et al., 2005, p.295).

His point of reference was the observation that females in this family produce extensive dry webs, of cribellate silk, across the surface of hard substrates such as soil or wood, centered upon an orifice such as a crevice or hole. The plane of the web is broken by a tubular retreat that extends perpendicularly into the depths of the orifice. Here, hidden from view, the female patiently waits until prey disturbs the strands of her webbing. When a human observer sees a female southern house spider, it is usually when she has emerged from her crevice retreat to secure her prey and is, momentarily, standing on the threads of her extensive sheet of cribellate silk.

The Filistatidae, which as a family is distributed worldwide, includes (as of 31 December 2011) 17 recognized genera, and 113 species of spiders (Platnick, 2012c).

The genus Kukulcania, which was named in 1967 by Pekka T. Lehtinen, presently curator emeritus of the Zoological Museum, University of Turku, Finland, is said to refer obliquely to the fierce Meso-American god Kukulcan. The derivation of that name, which means “plumed serpent” may have as much to do with its choice as did the god who bore it, though one wonders… Kukulcan’s likeness is represented by a human with protruding teeth, a bulbous nose, and a lolling tongue. Perhaps Dr. Lehtinen saw, in this spider’s visage, something reminiscent of the Meso-American god of old.

Filistatidae: Southern House Spider (Kukulcania hibernalis); eyes, Central TX--1995

Filistatidae: Southern House Spider (Kukulcania hibernalis); eyes, Central Texas --- 1995

We know that Lehtinen was, at least in those days, fond of creating names from figures in ancient mythology, but that seems to be the extent of our knowledge about his choice for this generic name. I shall have to ask him next time we have a chance to exchange communications.

All members of the Kukulcania are native to the Americas, as might be expected. Eight species and one subspecies are recognized (Platnick 2012b), the most common amongst them, in North America, being the southern house spider (Kukulcania hibernalis), which is well distributed throughout much of the New World.

The demeanor of this spider is anything but fierce. Males and females alike are well-known for their tendencies to play dead when threatened by a large animal such as man.

The females rarely wander from their hackled web nests, though I’ve found them wandering, from time to time, nocturnally.

The males are inveterate wanderers, actively searching for prey and mates.

Neither sex is provided with large chelicerae or fangs, and the chelicerae are rigidly fused at their base, so that they cannot articulate laterally with respect to one another. Thus, they are not well equipped to bite anything much larger than themselves.

They are known to bite humans when handled roughly, but the bite is neither very painful nor of any serious medical significance.

Filistatidae: Southern House Spider (Kukulcania hibernalis); male palp;Central T--1995

Filistatidae: southern House Spider (Kukulcania hibernalis); male palp;Central Texas --- 1995

Filistatidae: Southern House Spider (Kukulcania hibernalis); male palpal embolus; Central T--1995

Filistatidae: Southern House Spider (Kukulcania hibernalis); male palpal embolus; Central Texas --- 1995

The mystery of why these spiders are so often mistaken for Loxosceles spiders is not complicated. Actually, the two genre have more in common, in concrete terms, than might be imagined.

However, one anatomical feature that they do not share is the number and arrangement of their eyes.

The eyes of the Kulkucania are ensconced upon a prominence at the anterior of the cephalothorax, which is a convex structure itself in contrast to the unusually flat plane that characterizes the cephalothorax of the Loxosceles. The eyes also number eight in the Kukulcania, not the six eyes of the Loxosceles, and are clustered in a centralized, tight group, rather than being strung peripherally, in three distinct pairs (diads) as with the Loxosceles.

Though the southern house spider appears, at first glance, to have a dark streak on the cephalothorax suggestive of the violin of the Loxosceles, the seeming dark streak disappears when viewed under magnification. Instead one sees a prominent thoracic groove, the fovea, which, in combination with a bulbous pars cephalica that casts a darkened shadow, vaguely mimics a poorly defined fiddle, at least to the unpracticed eye.

References to Scientific Literature:

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