Tailed Daddy Longlegs Spider, Crossopriza lyoni

Crossopriza lyoni is a widespread species of cellar spiders that prefer to live in or around human structures. They are commonly known as Tailed Cellar Spiders, Tailed Daddy Longlegs Spiders, and occasionally Box Spiders. They all possess exceptionally long and fragile legs that can reach up to 2.4 inches long and a body length of that ranges from .098 to .28 inches. Their abdomens are distinctly square shaped when they are viewed from the side and their carapace is more or less circular shaped when viewed from above. They also possess two kinds of sound-producing organs and have six eyes.

The original range of C. lyoni is not known. They have been introduced into other parts of the world accidentally and are now pantropical in distribution. They are a regulated species in some countries and are frequently regarded as pests because of the large amounts of unsightly webs they build inside human homes. Some people, however, regard them as beneficial, as they are effective predators of mosquitoes and other arthropods. They are not harmful to humans.

This species belongs to the cellar spider family Pholcidae. They are commonly referred to as a tailed daddy longlegs spiders. C. lyoni and other cellar spiders are also frequently confused with two other invertebrates – the Harvestmen and the Crane Flies – both of which are also known as ‘daddy longlegs’. however, they aren’t closely related to cellar spiders – the latter is a fly; and the former, while also an arachnid, isn’t a spider at all.

It was first formally described in 1867 by the British naturalist John Blackwall from a collection of spiders from Meerut, Agra, and Delhi. They came from Francis Lyon, a captain of the Royal Artillery of the British Empire that was stationed in India. They were sent to his sister who presented them to Blackwall at the proposal of a mutual friend. Blackwall named the spider after Captain Lyon and expressed a hope that others may follow Lyon’s example in collecting specimens from foreign countries for the benefit of science. He placed the species under the genus Pholcus. In 1892, the French arachnologist Eugene Simon established the genus Crossopriza and later reclassified Pholcus lyoni to Crossopriza lyoni. Blackwell also described a peculiar case of hermaphroditism in one adult specimen, in which the left side was male and the right side was female.

This species is sexually dimorphic. The females are about .12 to .28 inches long. The males are slightly smaller at about .098 to .24 inches long, and have distinguished pedipalps. Both male and female possess very long and fragile legs. The males have somewhat longer legs than the females. The first pair of legs in larger male individuals can reach up to 2.4 inches long. The legs are gray to amber in coloration and they are covered with a number of small longitudinal brown colored spots. The ‘knee joints’ are brown, and the ends of the femur and tibiae are girdled with white. The males also possess a series of 20 to 25 spines on their femur. Their leg formula is I, II, IV, III – the front pair of legs being the longest and the third pair being the shortest.

The cephalothorax is wider than it is long. It is grayish-white to pale amber in coloration. The carapace is sub circular shaped. In the middle of the upper surface is a deep depression and a darker longitudinal band of color. C. lyoni, like some other cellar spiders, only have six eyes. They’re pearly white in color and they are located at the tip of the cephalothorax in two groups of three.

The abdomen is gray with white lateral stripes and a variety of dark and light patches on the sides and the upper surface. An irregular darker colored stripe runs lengthwise at the bottom surface. The abdomen is angular and rather box-shaped, with a small conical hump on the upper back.

They also have two types of stridulatory organs. The first type is found at the posterior tips of their cephalothorax in the form of two triangular projections. The spiders rub these structures with a matching pair of sclerotized plates at the anterior portion of the abdomen, creating sound. These structures are more outstanding in the females. They also possess stridulatory files on their chelicerae which are rubbed against the pedipalps to create sound. The second type is more outstanding in the males.

This species can be differentiated from other members of the genus through several ways: by the characteristic box shape of their abdomens; by the presence of two apophyses in the chelicerae of the males; or simply by geographic distribution.

A single male individual is able to copulate with several females. Mating is achieved with the male inserting both his pedipalps into the genital orifice of the female and transferring a previously prepared packet of sperm into her spermathecae. Due to the relative shortness of the male pedipalps compared to the sheer length of the legs of both male and female of the species, the spiders have to bring their bodies close to each other, giving the notion of ‘snuggling’. This goes on for about 40 minutes. In rare occurrences, the females may eat the males after copulation.

The eggs are deposited by the female 5 to 6 days after copulation. After the laying the eggs, the females will bind them into a ball with tiny quantities of silk. Then, they clutch the resulting egg sacs with their mouthparts and carry them around. Eggs that, in some way, fall from the loose bunch do not hatch. The females still feed during this time, temporarily setting their burdens aside while they eat, then picking them up again. They also frequently modify their grip. Occasions of the females eating some of their own eggs have been recorded. It is assumed that they only consume the infertile ones, as unfertilized eggs occur at high enough rates among this species.

5 to 54 spider lings will eventually hatch from their eggs, 11 to 13 days after egg-laying. The spiderlings don’t leave the eggs right away. They hatch partially, but otherwise stay in the bundle their mothers carry for at least a day. Eventually they leave it completely. They stay mostly inactive for two to three days after hatching until their first molt. The spiderlings which are separated from their mothers mature more quickly than those which remain nearby. They become adults about 80 days after hatching. This species has a lifespan of at least 194 days.

C. lyoni are vigorous hunters. Hanging upside down, they will quickly catch prey caught in their irregular cobweb-like webs. If they are hungry enough, they also actively chase that fly close to their webs. They don’t use their fangs when hunting, instead they throw their silk over their prey and then wrap them loosely using their hind legs. They will only bite them when they begin to feed, which can occasionally be as long as six days after capture. They also actively clean their webs by regularly eliminating carcasses. When the webs become too dirty, they build new ones.

Newly hatched spiderlings are just as active as the adults. Two to four days after their first molt they can already overpower mosquitoes four times their own size. The spiderlings may share prey they caught themselves or prey caught by their mother. They may also engage in cannibalism by preying on their own siblings.

C. lyoni, like other cellar spiders, will aggressively rotate their bodies in small circles when threatened. They can do this very quickly, blurring their outline and making them difficult to see. This behavior earned cellar spiders one of their common names – vibrating spiders – and is assumed to be an antipredator adaptation. If this doesn’t work, they will drop from their webs to the ground, or awkwardly fee with their characteristic long-legged pace.

They are synanthropic, preferring to live inside or near human-made structures. They normally build irregular webs in corners of rooms, cellars, basements, and beneath ceilings. They are readily transported by human activity, particularly as hitchhikers in ships. As a result, this species has been introduced to most of the world, including Asia, Africa, Australia, Europe, North and South America, and some Pacific islands.

Their place of origin is not known but have been variously posited to be Africa.

Image Caption: Crossopriza lyoni – Tailed daddy-long-leg spider (actually a cellar spider – Pholcidae), sometimes known as the box spider. Credit: Obsidian Soul/Wikipedia (CC BY-SA 3.0)