The biology of Portia fimbriata, a web-building jumping spider (Araneae, Salticidae) from Queensland: intraspecific interactions

Portia fimbriata (Doleschall) is an unusual salticid because it spins webs and uses its own webs and those of other species in predation. However, the courtship and threat displays of this species are more like those of typical, cursorial salticids than like typical web-building spiders. During male-female interactions, males perform leg-waving and leg-shaking displays, with legs I and II extended stiffly forward, while distant from the females. Before mounting they tap the females with their legs; and after mounting they tap, scrape and stroke the females' abdomens. Copulation takes place on or near the female's web or on the webs of other species. Hunched-legs displays, with legs I–III highly flexed and held to the side of the body, occur in male-male interactions. Also, during male-female and female-female interactions, females perform hunched-legs displays, strike, charge, ram, embrace, grapple with and leap at conspecifics. Sometimes they lose legs while grappling. After female-female interactions associated with maternal webs, if the resident decamps, the intruder eats the eggs left behind on a suspended leaf, spins a new egg-case over the destroyed one, and oviposits. Adult and sub-adult males co-habit in webs with sub-adult females for as long as 48 days and mate when the spiders mature.     

The biology of Tauala lepidus,a jumping spider (Araneae: Salticidae) from Queensland: display and predatory behaviour

Abstract

The display and predatory behaviour of Tauala lepidus Wanless, an abundant salticid in north Queensland rainforests, was investigated in the laboratory and, to a lesser extent, in nature. T. lepidus leapt and walked into alien webs to catch spiders and insects, and was captured and fed on by other spiders. Females ate each other’s eggs. During intraspecific interactions, a complex repertoire of displays was used. Courtship versatility occurred, each individual male having a conditional strategy of different behaviours depending on whether the female is at or away from her nest, and whether she is adult or subadult. Yet other combinations of displays occurred during male-male and female-female interactions. Apparently, pheromones on nests and draglines of females released male courtship. Abdomen twitching, a behaviour common to the display repertoires of many salticids, was an especially complex and pervasive behaviour of T. lepidus. T. lepidus also twitched its abdomen when it contacted alien webs and preyed on other species of spiders. The behaviour of T. lepidus is compared to that of Jacksonoides queenslandica Wanless, a species from the same group (Astieae).     

Prey preferences ofPortia fimbriata,an araneophagic,web-building jumping spider (Araneae: Salticidae) from Queensland

Portia fimbriata from Queensland, a previously studied jumping spider (Salticidae), routinely includes web-building spiders and cursorial salticids in its diet, both of these types of prey being dangerous and unusual prey for a salticid. The present paper is the first detailed study ofP. fimbriata's prey preferences. Three basic types of tests of prey preference were used, providing evidence that (1)P. fimbriata males and females prefer spiders (both web-building spiders in webs and salticids away from webs) to insects; (2)P. fimbriata males and females prefer salticids to web-building spiders; (3)P. fimbriata males and females prefer larger spiders to smaller spiders; (4) there are intersexual differences in the preferences ofP. fimbriata for prey size, females preferring larger prey and males preferring smaller prey; and (5)P. fimbriata's prey preferences are not affected by a prior period without food of 2 weeks. When preferences were tested for by using both living, active prey and dead, motionless lures, the same preferences were expressed, indicating thatP. fimbriata can distinguish among different types of prey independent of the different movement patterns of different prey.     

Predatory and nesting behaviour of Cocalus gibbosus,a spartaeine jumping spider (Araneae: Salticidae) from Queensland

Abstract

Cocalus gibbosus was studied in the field in Queensland and in the laboratory. This is the first behavioural study of a species from the spartaeine genus Cocalus. C. gibbosus often omitted elements which are usually present in the predatory sequences of typical salticids and tended to lunge at prey from close range rather than leap from afar. Experiments showed that C. gibbosus prefers moths to other prey. In nature, C. gibbosus moulted and oviposited on silk sheets spun against tree trunks, and in the laboratory on sides of cages or blocks of wood, but this species never built an enclosing nest like typical salticids nor a large prey-catching web like some other spartaeines. C. gibbosus stalked across alien webs to catch spiders and insects, but it did not make vibratory signals. It did not stick to cribellate or ecribellate glue on alien webs. The behaviour of C. gibbosus is compared to that of other spartaeine salticids.     

The biology of ant-like jumping spiders: intraspecific interactions of Myrmarachne lupata (Araneae, Salticidae)

Myrmarachne lupata is an ant-like salticid in which males have very large chelicerae. The display repertoire of this species is unusually large and complex for a salticid spider. Each individual male uses one of three different mating tactics depending on the female's maturity and location. With adult females outside nests type 1 courtship occurs which seems to be a form of visual communication and includes specialized movements and postures of the legs, palps and body. With adult females inside nests, males use type 2 courtship, which seems to be a form of non-visual communication and consists primarily of probing with the legs on the silk; males mate with receptive females inside the nests. With subadult females, males first use type 2 courtship then spin an adjacent silken chamber and cohabit. After she moults and matures, mating occurs inside the nest. Vacant nests of conspecific females, but not those of another sympatric salticid species, elicit courtship behaviour from males. During male-male interactions, embracing occurs with the large chelicerae spread apart. Females and subadults also display, and different displays occur in interactions depending on the sex/age classes of the spiders involved. Despite the unusual morphology of these spiders, their individual displays are similar to those of more typical salticids. During copulation males stand beside the female instead of over or on her as occurs with typical salticids.     

The biology of ant-like jumping spiders (Araneae, Salticidae): prey and predatory behaviour of Myrtnarachne with particular attention to M. lupata from Queensland

Myrtnarachne is a genus of ant-like salticids. Eight species were observed feeding, in nature, in Australia, Kenya, Malaysia and Sri Lanka, on varied types of insects but not ants. The behaviour of M. lupata , from Australia, was studied in the laboratory. Predatory sequences were found to differ considerably from those of typical salticids. Attacking by lunging instead of leaping and the pronounced use of pre-attack tapping are especially noteworthy. The unusual behaviour of M. lupata when preying on insects is consistent with maintenance of ant mimicry. Myrmarachne lupata also preys on the eggs of other spiders which it extracts from their nests. The males of many species have very large chelicerae, and the large chelicerae of M. lupata males influence the course of predatory sequences, with insects and with eggs.     

The comparative study of the predatory behaviour of Myrmarachne, ant-like jumping spiders (Araneae: Salticidae)

The predatory behaviour of 31 species of Myrmarachne , ant-like salticids, was studied in the laboratory and the field. The ant-like morphology and locomotion of these spiders appears to function primarily in Batesian mimicry. No evidence was found of Myrmarachne feeding on ants. However, predatory sequences were found to differ considerably from those typical of salticids. Instead of stalking and leaping on prey, Myrmarachne lunged at prey from close range. Myrmarachne used its legs I to tap prey before lunging, another unusual behaviour for a salticid. Myrmarachne fed on a wide range of arthropod prey in nature and the laboratory, but appears to be especially efficient at catching moths. Also, Myrmarachne tends to open up, or enter into, other spiders' nests and eat other spiders' eggs. Myrmarachne males were less efficient than females, in laboratory tests, at catching various types of arthropod prey, but they appear to be as efficient as females at oophagy. Myrmarachne tend to use webs of other spiders as nest sites, but no evidence was found of Myrmarachne preying on spiders in webs. It appears that the unusual features of Myrmarachne's predatory and nesting behaviour are important in enabling these spiders to preserve their ant-like appearance.     

Social behaviour in a web-building lynx spider, Tapinillus sp. (Araneae: Oxyopidae)

Social behaviour involving cooperative prey capture and communal feeding is reported for the first time in the spider family Oxyopidae (lynx spiders), in a web-building species of the genus Tapinillus. This social spider inhabits communal webs that may contain several dozen individuals, including adults of both sexes and juveniles of different cohorts. Its colonies occur in clusters and appear to be long-lived, much like those of non-territorial permanently social species such as Anelosimus eximius (Theridiidae) or Agelena consociata (Agelenidae). However, unlike colonies of these other cooperative spiders, the colonies of the social Tapinillus do not have highly female-biased sex ratios. The possible explanations for this difference are discussed.     

Predator-prey interactions between web-invading jumping spiders and a web-building spider, Holocnemus pluchei (Araneae, Pholcidae)

Three species of web-invading salticid spiders, with different predatory strategies, were tested with Holocnemus pluchei in the laboratory: Portia fimbriata and Portia labiata , which practise aggressive mimicry, and Euyattus sp., which leaps from outside on to spiders in webs but does not practise aggressive mimicry. Portia was shown to be more efficient than Euryattus at catching H. pluchei. Portia fimbriata from Queensland was more consistent at using aggressive mimicry than was Portia labiata and was also more efficient at catching H. pluchei . The web-invaders that were more efficient at catching H. pluchei were also better able to avoid setting off bouncing, a special defence behaviour used by H. pluchei . An experiment, in which H. pluchei was artificially induced to bounce whenever the predator was near, provided additional evidence that bouncing is effective in defending H. pluchei against web-invaders.     

Comparative biology of Portia africana,P. albimana,P. fimbriata,P. labiata,and P. shultzi,araneophagic, web-building jumping spiders (Araneae: Salticidae): Utilisation of webs,predatory versatility,and intraspecific interactions

Abstract

Portia is a behaviourally complex and aberrant salticid genus. The genus is of unusual importance because it is morphologically primitive. Five species were studied in nature (Australia, Kenya, Malaysia, Sri Lanka) and in the laboratory in an effort to clarify the origins of the salticids and of their unique, complex eyes. All the species of Portia studied were both web builders and cursorial. Portia was also an araneophagic web invader, and it was a highly effective predator on diverse types of alien webs. Portia was an aggressive mimic, using a complex repertoire of vibratory behaviour to deceive the host spiders on which it fed. The venom of Portia was unusually potent to other spiders; its easily autotomised legs may have helped Portia escape if attacked by its frequently dangerous prey. Portia was also kleptoparasitic and oophagic when occupying alien webs. P. fimbriata from Queensland, where cursorial salticids were superabundant, used a unique manner of stalking and capturing other salticids. The display repertoires used during intraspecific interactions were complex and varied between species. Both visual (typical of other salticids) and vibratory (typical of other web spiders) displays were used. Portia copulated both on and away from webs and frequently with the female hanging from a dragline. Males cohabited with subadult females on webs, mating after the female matured. Adult and subadult females sometimes used specialised predatory attacks against courting or mating males. Sperm induction in Portia was similar to that in other cursorial spiders. Portia mimicked detritus in shape and colour, and its slow, mechanical locomotion preserved concealment. Portia occasionally used a special defensive behaviour (wild leaping) if disturbed by a potential predator. Two types of webs were spun by all species (Type 1, small resting platforms; Type 2, large prey-capture webs). Two types of egg sacs were made, both of which were highly aberrant for a salticid. Responses of different species and both sexes of Portia were quantitatively compared for different types of prey. Many of the trends in behaviour within the genus, including quantitative differences in predatory behaviour, seemed to be related to differences in the effectiveness of the cryptic morphology of Portia in concealing the spider in its natural habitat (‘effective crypsis’). The results of the study supported, in general, Jackson & Blest’s (1982a) hypothesis of salticid evolution which, in part, proposes that salticid ancestors were web builders with poorly developed vision and that acute vision evolved in conjunction with the ancestral spiders becoming proficient as araneophagic invaders of diverse types of webs.     

The meaning of predatory specialization as illustrated by Aelurillus m-nigrum, an ant-eating jumping spider (Araneae: Salticidae) from Azerbaijan

The distinctions between a predator's diet, its prey-choice behaviour and its preference are illustrated in a study of Aelurillus m-nigrum Kulczyn'ski, a salticid spider from Azerbaijan. The natural diet of A. m-nigrum was determined from records of individuals feeding in the field (N=58). Ten arthropod orders were represented. Nine were from the class Insecta (Coleoptera, Collembola, Diptera, Heteroptera, Homoptera, Hymenoptera, Lepidoptera, Orthoptera, Psocoptera) and one from the class Arachnida (Araneae). Of 50 insects among the prey, 21 (42%) were Hymenoptera, with ants (family Formicidae) alone accounting for 31% of all prey records. Although the majority (69%) of the natural prey were not ants, results from prey-choice testing in the laboratory implied that A. m-nigrum preferred ants as prey. However, this preference was evident only when the testing environment included sand and a small stone. Our findings illustrate the importance of not conflating the concept of a predator's preference with the concept of a predator's natural diet and illustrate that physical features of a predator's habitat may be an important factor in influencing how strongly preference is expressed.     

Web-building and predatory behaviour of Spartaeus spinimanus and Spartaeus thailandicus, primitive jumping spiders (Araneae, Salticidae) from South-east Asia

Behavioural data are provided for the first time for two species of Spartaeus, S. spinimanus from Singapore and Thailand and S. thailandicus from Thailand. These jumping spiders (Araneae, Salticidae), from the primitive subfamily Spartaeinae, build large sheet webs on tree trunks and they capture prey—especially moths—on or near the web by walking to and lunging at them. When walking, Spartaeus waves its palps and legs in an unusual way. In formal tests, Spartaeus captured moths more frequently than flies and captured both moths and flies more readily when with their webs than without their webs.     

Use of prey-specific predatory behaviour by North American jumping spiders (Araneae, Salticidae) of the genus Phidippus

Prey-capture behaviour of seven species of Phidippus is studied using two types of prey, house flies (adult Musca domestica ) and caterpillars (cabbage loopers, larval Trichoplusia ni ). Each species is shown to be a versatile predator which uses a different prey-specific prey-capture behaviour depending on whether prey is a fly or a caterpillar: spiders approached the two types of prey differently and leapt on them from different distances. Interspecific differences among Phidippus species are not pronounced, cxcept for variation in the distance from which spiders jumped and the spider's success at capturing a fly on the first try.     

Predator-prey interactions between jumping spiders (Araneae, Salticidae) and Phokus phalangioides (Araneae, Pholcidae)

Portia is a genus of specialized web-invading salticids that use aggressive mimicry. Some other salticids leap into webs to catch spiders but do not use aggressive mimicry. Pholcus phalangioides is a web-building spider with a special defensive behaviour—called whirling—in which it swings its body around in a circle while keeping its long legs on the silk. Pholcus phalangioides is preyed on by Portia and probably other salticid spiders in nature. Interactions between P. phalangioides and 13 species of salticids were studied in the laboratory to compare how effective salticids with different styles of predation were at catching the pholcids. Four species of Portia were studied and each was more efficient at catching P. phalangioides than were the other nine salticids tested. For one species—Portia fimbriata—individuals from three different populations were studied. The Queensland P. fimbriata used aggressive mimicry more consistently and were more efficient at catching P. phalangioides than were the other species of Portia and the other populations of P. fimbriata . The salticids that were the most efficient at catching pholcids were also better able to avoid setting off whirling by the pholcids. An experiment in which pholcids were artificially induced to whirl whenever the predator was near provided additional evidence that whirling is an effective defence of pholcids against predation by salticids.