Phrurolithus festivus is a spider in the family Phrurolithidae. It was originally distributed only in the Palaearctic and was introduced into Canada. The highly adaptable species inhabits a variety of both dry and wet habitats and can also be found in man-made habitats, but generally prefers open areas.
A special characteristic of P. festivus, which it shares with other Phrurolithidae species, is the imitation of ants in the form of Batesian mimicry. To do this, the species imitates the movements of ants and also mimics them visually. According to the principle of Batesian mimicry, this imitation serves as a deterrent to predators, since ants are unpopular prey for many predators due to their defensiveness.
Phrurolithus festivus, which is diurnal like all species of the genus, also moves around quickly according to the peculiarity of Phrurolithus and preys on any arthropods smaller than the hunter itself as an active running hunter. Mating is not preceded by courtship behavior. A mated female lays several egg cocoons with comparatively few eggs some time after mating. Otherwise, the life cycle of the spider is little studied.
Characteristics According to Sven Almquist (2006), the female of P. festivus can reach a body length of 2.7 up to 3.8 as well as an average of 3.1 ± 0.2 and the male one of 2.6 up to 3 as well as an average of 2.8 ± 0.1 millimeters. Thus, like all Phrurolithidae, it is a smaller spider species. The basic body structure of the spider resembles that of other Phrurolithus.
The leg formula, as in many spiders, is 4-1-2-3. +Arrangement of the spines on the two front pairs of legs according to Cleopatra Sterghiu (1985)Leg pairFemur (thigh)Tibia (splint)Metatarsus (Heel link)1v1, d1, pl15 pairs in 2 rowsspines arranged in the formation 4,4 or 2,4 in a row2 –4,4spines arranged in the formation 4,4 or 2,4 in a row
Legend for indicated directional positions:
d = dorsal (above) pl = prolateral (laterally in front) v = ventral (below)
In this species, the opisthosoma (abdomen) appears angled and about the same width anteriorly (front) as posteriorly (back).
Sexual dimorphism Phrurolithus festivus, like many spiders, exhibits a pronounced sexual dimorphism (difference in sexes). This is noticeable not only in the dimensions but also in the coloration of females and males. In addition, as is common in Phrurolithus, the male has a scutum (sclerotized, or hardened plate) on the opisthosoma, which the female lacks.
Female
In the female, according to Almquist, the carapace (dorsal shield of the prosoma, or anterior body) can have a length of 1.04 up to 1.35 and an average of 1.2 ± 0.06, and a width of 0.86 up to 1.09 and an average of 0.97 ± 0.05 millimeters. The ratio between the length and width of the carapace is 1.16 to 1.34 in the female, with an average value here of 1.23 ± 0.05. The carapace is also inclined at 52 degrees in the female.
The carapace of the female is dark yellowish brown and the chelicerae (jaw claws) are brownish in color. Promarginal (inside anteriorly) the chelicerae each have three teeth and retromarginal (inside posteriorly) one tooth. The sternum (thoracic shield of the prosoma) has a brown ground color, with a darker coloration marginally going into the width. The legs are yellowish brown in color, and the femora (thighs) appear darker. +Lengths of the legs of the female in millimeters with a body length of 3 up to 3.5 millimeters according to SterghiuLeg pairFemurPatella (limb between femur and tibia)Tibia (splint)Metatarsus (calcaneal phalanx)Tarsus (foot link)Total length10,840,410,990,790,483,5120,890,380,640,710,463,0830,740,350,510,710,462,7741,040,410,941070,64,06 The opisthosoma of the female has dorsally a dark brown ground coloration as well as iridescent setae (chitinized hairs). Anterolaterally (anteriorly lateral) there are two white spots on the opisthosoma, while median (centrally) on this part of the body there is a white zigzag band. Not infrequently, there are narrow and pale angular spots posteriorly on the opisthosoma. Ventrally, the opisthosoma appears grayish and it also has small pale spots there.
Male
In the male, the carapace is 1.2 to 1.38 and on average 1.27 ± 0.04 millimeters long and 0.97 to 1.2 and on average 1.06 ± 0.05 millimeters wide. The length-to-width ratio of the carapace here is 1.13 to 1.3 and mostly 1.21 ± 0.04, and its inclination is 28 degrees.
The carapace of the male has a dark brown coloration and is covered medially on the cephalic (head) area with white and posteriorly with radial rows of equally white setae. The chelicerae of the male are dark brown in coloration and, unlike those of the female, do not bear teeth. The sternum is brown colored as in the female and marginally darker, but here less projecting. The legs of the male have a yellowish brown basic coloration. Here the femora are dark brown and the coxae (hip limbs) as well as the trochanters (thigh rings) are light yellowish brown in color. +Lengths of the legs of the female in millimeters with a body length of 2.45 up to 3 millimeters according to SterghiuLeg pairFemurPatellaTibiaMetatarsusTarsusTotal length10,920,430,840,810,513,5120,840,350,660,660,462,9730,740,350,510,690,432,7241,040,430,891,070,584,01 The dorsal side of the opisthosoma shows a black coloration in the male, while there are two spot-like formations of white setae anterolaterally. As in the female, a white zigzag band runs median on the dorsal side of the opisthosoma in the male. Additionally, in the male there is a tuft of white setae on the apex (tip) of the opisthosoma. The ventral surface of the opisthosoma here is yellowish brown to brown in color.
Genital morphological characteristics
The pedipalps (transformed extremities) from the male of P. festivus are almost black in color. At the same time the femora appear dark brown. A single pedipalpus can sometimes be distinguished from those of other male Phrurolithus by the retrolateral (laterally recessed) apophysis (chitinized process) on its tibia (splint), which is very large in comparison here and has a shovel-shaped appearance. The basal (located at the base) part of a bulb (male sex organ) of the species is prominent. Another tegular (posterior) apophysis on each of the two pedipalps is broadly built in P. festivus and has a curved tip. The curved embolus (third and last sclerite or hard part of a bulb) appears peg-like.
The epigyne (female sex organ) of P. festivus is sometimes characterized within the genus by its posteriorly sclerotized (hardened) plate. In addition, the sex organ projects slightly beyond the epigastric (located at the stomach) furrow. The epigyne of has a rather smaller copulatory opening and the copulatory ducts are comparatively short and wide. The primary spermathecae (seminal pockets) of the species are transverse (transversely) laid out, and the secondary ones are large and oval shaped.
Differentiation from other Phrurolithus Since all Phrurolithus including P. festivus are very similar to each other and especially the spot pattern is presumably present in such a way in all species of the genus, a differentiation of these as well as of P. festivus is only given on the basis of the genital morphological characteristics.
In Phrurolithus minimus the pedipalps of the male are black striped and a single tibial apophysis attached to it is strongly curved. A bulb here has one apophysis each distal (away from the center of the body), tapering and curved. The epigyne of P. minimus has copulatory openings located medially. For Phrurolithus nigrinus, the curved tibial apophysis with a long, separated apex on a single pedipalpus in the male is most typical, while the epigyne of the species is characterized by a large median pit. The epigyne of P. nigrinus is characterized by a large median pit. For the male of Phrurolithus pullatus is typical with symmetrical tip equipped tibial apophysis on a pedipalpus. Furthermore, here one bulb has two distal apophyses each, which overhang the embolus. The epigyne of this species has laterally situated copulatory openings. In Phrurolithus szilyi, the fifth species occurring in Central Europe, the tibial apophysis on a pedipalpus of the male is provided with a little separated apex and a bulbus with broad and roundish distal apophysis. The epigyne, similar to that of P. nigrinus, has a large median pit, but here it appears indented on the anterior margin.
Incidence
The original range of P. festivus extended over Europe, North Africa, Turkey, Caucasia, Russia (European to Far Eastern part), Kazakhstan, Iran, China, Korea, Japan. In Canada it was introduced moreover. Also in Europe itself the species is represented area-wide and is missing in continental Europe only in Croatia, Bosnia and Herzegovina and Kosovo as well as additionally on the Russian double island Novaya Zemlya, in Franz-Josef-Land, Iceland and on the archipelago Spitsbergen, Sardinia, the Balearic Islands, Crete and Cyprus. In North Africa, records of the spider from Tunisia and Egypt are lacking.
Phrurolithus festivus is widespread especially in Western and Central Europe. On Great Britain it is common especially in the southern part of the island, while its occurrence there is highly scattered in the west. To the north, the species' range on Britain extends into the central part of Scotland.
Habitats Phrurolithus festivus inhabits a wide range of both dry and wet habitats (habitats) and has sometimes been recorded in grasslands, gardens, litter layers, and the underside of stones. The same is true near water-filled pits and the underside of stones in quarries. Other proven habitats of the species include dry grasslands, dune heaths, ground litter under juniper (Juniperus), and the underside of stones on limestone surfaces. The spider has also been recorded in vineyards, sunny forests, and on beaches.
Phrurolithus festivus can be found at altitudes up to 1,350 meters above sea level. In the United Kingdom, this altitude is limited to 700 meters above sea level.
Hazard The population situation of P. festivus is evaluated differently depending on the country. In Germany, for example, it is very common and its populations there are considered to be stable in both the long and short term. Because of this, the species is classified as "not endangered" in the Red List of Threatened Species of Animals, Plants and Fungi of Germany (2016). The same was also the case in the previous version of this Red List from 1996. The spider is also included in the same category in the Red List of Spiders of Carinthia (1999).
Similar to Germany and Carinthia, P. festivus is listed in the UK Red List (2017) in the category LC ("Least Concern", or not endangered) according to IUCN standards. The same is the case for the Red List of Arachnids (Arachnida) of Norway (2015), while the spider is included in the Red List of Spiders of the Czech Republic (2015) in the category ES ("Ecologically Sustainable", or ecologically adaptable), considering the population situation there. The spider is listed in the Red List of Arachnids of the Czech Republic (2015) in the category ES ("Ecologically Sustainable", or ecologically adaptable).
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