Daddy Longlegs

The term daddy longlegs is used to describe a group of spiders. The etymology of the name originates from the long length of the leg. The name is given to the group of spiders that are classified into the order called Araneae, these spiders are all members of the same family. They belong to the family called Pholcidae. The term is used to describe different genera and species of spider classified under the family, it is thus concluded that the term is an umbrella term. It is evident that the common name is not used in any form of taxonomic classification, daddy longlegs is also referred to as harvestmen. 

The members of the Pholcidae family are known to be araneomorph spiders. The expression is used to describe a group of spiders that have elongated fangs,  these fangs point in a diagonally forward direction. This can also be seen in the daddy long leg spiders. The family consists of more than 6000 species of spiders, the araneomorph spiders are also known as the tangle web group of spiders. 

The most distinguishing feature of this group of spiders is the presence of an elongated body and comparatively a very small body. According to some biologists, these spiders share more similarities with scorpions rather than with true spiders. Due to the extremely small size of the body, they lack a clear distinction between cephalothorax and abdomen, this creates an illusion of broad fusion that makes the juncture between the two segments almost indiscernible. This is the main reason that the spiders are subjected to debate around the morphological closeness with either species. 

Apart from their elongated legs, another morphological marker of the harvestmen is the colour of the body, they are found in cream to pale brown colour. Some species of daddy longlegs are known to have dark coloured markings on the lower abdomen and legs. 

The common name of the daddy long leg spider includes the following: harvestmen,  long-bodied cellar spider, skull spider, daddy long-legger, and long daddy spider.

The article discusses the general taxonomic classification of the long daddy spider, the food habits, and the habitat of the spider. Morphological features, reproduction and life cycle of the spider is also described in the article.

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Figure illustrating daddy longlegs spider

Taxonomic Classification

Taxonomy is the branch of science that deals with the classification of all plants and animals. The classification system is based on the similarity and dissimilarities of the organism, based on these features they are categorized into different taxa. The term taxa are used to define the hierarchical level at which the organism is classified. A question that arises is the need for taxonomic studies. Taxonomic classification lays the basic understanding of the organism, it also helps to understand the interspecies relationship of the organism. Apart from these taxonomical studies helps in establishing a phylogenetic relationship. It also helps in predicting the ecological and anatomical modifications that were adapted during evolution.

Before understanding the taxonomic classification it is critical to understand the term is an umbrella term and a general form of the taxonomic classification system mentioned here. The classification of the daddy longlegs is mentioned as follows.

The animal is classified into the kingdom Animalia, the basic requirement to be categorized into this kingdom is that the animal must be multicellular and the body structure of this animal must be made up of eukaryotic cell type. Members of this kingdom uptake organic nutrients from the environment to sustain their life. The animal kingdom is further divided into phylum. 

The daddy longlegs is classified into phylum Arthropoda, the main features of the member of this phylum are the presence of an exoskeleton, a segmented body, and paired jointed appendages. Another critical feature of this phylum is the presence of the compound eyes. A common question that comes into mind while discussing the phylum is “are daddy longlegs insects?” The harvestmen are spiders and a majority of spiders are classified as insects, it can be said that the phylum constitutes almost all the species of insects. The daddy longlegs spiders lack a thick hard exoskeleton that protects the body which is a common feature seen in insects (have a thin layer), but they are segmented and have compound eyes. The presence of joined elongated limbs are the characteristic feature of the spider, hence it can be said that they are rightly placed at the taxonomic level. The phylum is further divided into the subphylum.

They are classified into a subphylum called Chelicerata, the most important members of this subphylum are sea spiders, arachnids. The arachnids are the group of joined leg invertebrates, this group constitutes scorpions, spiders, and potentially horseshoe crabs. The distinguishing feature of this subphylum is its body arrangement. The body plan of the members of these groups is defined by the presence of the two tagmata, the prosoma and the opisthosoma. The body is segmented but a unique feature is a fused cephalothorax and there is no clear distinction between the segments. These features are exceptionally prominent in the harvestmen species of spiders.

The subphylum is further branched into class, the harvestmen species belongs to the Arachnida class. The primary distinguishing feature is the presence of elongated appendages which is one of the morphological markers of the harvestmen. Most of the members of arachnids have eight legs, and they are generally terrestrial species. All these requirements are satisfied by the spider species. 

They are further classified into the order Araneae, this order is commonly known as the order of the spiders. They have specialized mouthparts called chelicerae, the appendage is also associated with glands. The primary role of the appendage is to inject venom. Another fascinating feature is the presence of the spinnerets, these are the organs that are primarily involved in the secretion of silk or spider web. The organ is usually anatomically positioned on the underside of a spider's opisthosoma, and is segmented. All these features are present in all the daddy long leg spider species. Order is divided into an infraorder called Araneomorphae, the characteristic feature is the presence of diagonally positioned fangs which is among the most vital morphological features of daddy longlegs. 

Harvestmen are then classified into the family called Pholcidae, they are known to have a thin and segmented class. There are about 94 different genres that are classified into the family. The most prominent genus of the family is Pholcus, there are about 7,000 species of daddy longlegs. Almost all the important species are classified into the genus. The example of some of the species are as follows, 

• Pholcus phalangioides

• Holocnemus pluchei

• Phalangium opilio

• Crossopriza lyoni

• Smeringopus pallidus

• Texella reyesi

• Leiobunum vittatum

• Texella reddell

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 Figure illustrating Phalangium opilio

Morphological Features 

The morphology of an animal refers to the physical characteristics of animals. The most distinguishing fact about daddy long legs is the presence of elongated jointed limbs. A common feature that is present in most spiders is the presence of 8 legs, but the arrangement of these limbs differ according to the species. The harvestmen are recognised to have jointed limbs. They are known to have a thin body, which is unique as most spiders are known to have a hairy appearance. The size of the body is drastically smaller when compared to the size of the limbs, the body is described as peanut-shaped and the length of the body is 2 t o10 mm which when converted into inches is 0.08 to 0.39 inches in length. The length of the limbs is estimated up to 50 mm which is approximately 1.97 inches long.

Among the important morphological markers, eyes of the spider are also discussed. A common question that comes to mind is “are daddy longlegs blind?” They are not blind. Harvestmen have compound eyes, the arrangements of eyes vary according to the species. The basic arrangement pattern is described as eyes arranged in two lateral groups of three and two smaller median contiguous eyes. Arrangements of eight and six eyes are also found in different species. 

The morphology is also distinct from other spiders as they have a fused cephalothorax and the segmentation is not distinctly visible in this group of spiders. The body pattern of the spider can be divided into two tagmata, the prosoma, and opisthosoma, which is joined by a small, cylindrical pedicel. The p[rosoma is defined as the cephalothorax (fused head and thoracic cavity), the opisthosoma is defined as the abdomen region of the body.

Harvestmen have developed chelicerae. The term is used to define the anatomically modified mouth part of the long daddy spider. These are the organs that serve the primary role of injecting venom into the prey, they are associated with glands that release venomous secretions. The harvestmen chelicerae are also known as fangs.

The colour of the body also varies according to the species but they are generally found in colour ranging from cream to pale brown, another morphological marker is the presence of the darker markings on the lower part of the body like legs and abdomen.

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Figure illustrating harvestmen (Pholcus phalangioides)

Habitat and Distribution

These spider species have a global distribution one of the major reasons for this is the species diversity of the group. Since there are more than seven thousand species it is apparent that they are distributed widely. Although they have a global distribution the preferred habitat of these spiders is the geographical location that has a warmer climate, for example, temperate and tropical locations. They are rarely seen in polar regions. Another intriguing fact about their habitat adaptation is that they are found in both wild and human settlements (houses). 

They live in webs, these are created by spinning webs that are secreted by the body. The organ that secretes the web is called spinnerets. The webs that are found in the wild are generally found in areas that are dark and damp recesses such as in caves, under rocks and loose bark, and in abandoned mammal burrows. The webs are built in a distributed area, where there is minimal light penetration in urban areas or houses.

The geographical distribution range includes countries like Australia, America, South Africa. They are also found in Europe and Asia.

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Figure illustrating web of harvestmen

Diet

These spiders are carnivore animals. It is very interesting to note that this group of spiders feed on other species of spiders. The diet of the daddy longlegs spiders includes a variety of insects and small spiders. They also feed on aphids, mites and licks.  Apart from hunting adult spiders they also eat spiders' eggs. An intriguing fact about the food habits of the daddy longlegs spider is their cannibal nature. The term is used to define eating the members of their species. This behaviour is seen in the case of resource scarcity. This is a rare behavioural trait.

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Figure illustrating daddy longlegs eating.

How Do Daddy Long Legs Mate?

These are sexually reproducing organisms. Upon successful fertilization they lay eggs, thus are termed oviparous animals. The parental care in these animals is minimal, they generally lay eggs in an undisturbed area. They lay approximately 6 to 8 eggs. A unique feature of this group is that they lay both fertilized and unfertilized eggs. This is mainly done to increase the probability of survival from the predators. Another unique anatomical modification that is seen in these spiders is the ability to store sperm. The female's long legs have a genital cavity, which serves as the site of sperm storage. These spider groups are polygamous in nature that is an individual can mate with multiple individuals.

Sexual dimorphism is prominent in these spiders, they differ in body size and genital organs, for example, the difference in size and characteristics of chelicerae, pedipalps, and other structures. The males of some species also possess anal glands or sternal glands, as well as secretory structures, which are known as adenostyles. These are absent in the female members. Males have a long protrusible penis whereas the female has an ovipositor that is specifically used to lay eggs.

The average lifespan of these spiders varies according to the species. The lifespan generally ranges from 223-774 days.

Predators

The natural predators of the spiders are birds, frogs and other large predatory insects. They are also predated by several different species of lizards. Among spiders, they are primarily hunted by jumping spiders of the Salticidae family. These are large hairy spiders that include harvestmen as their food source.

Summary: At a Glance.

• They belong to a family called Pholcidae.

• They have a global distribution

• The preferable habitat includes a location with a warmer climate.

• There are about seven thousand different species of harvestmen.

• They are carnivorous animals

• The diet includes insects and other spiders.

• They are sexually reproducing animals.

• The natural predators of the group include birds, lizards and other spiders.

• The most distinctive morphological feature is the presence of elongated jointed legs.

• They are known to have a thin and small body as compared to the legs.

• The legs are approximately five times larger than the body.