Eight-leggedTricksters Spidersthat specializein catchingother

Robert R. Jackson

Spiders arewell knownas preda- strugglesof a trappedinsect. It thereby tors of , but some even eat lures the residentspider close enough their own kind. For most spe- Use of deceit may be to be attacked (Bristowe 1941, cies, eating other spiders appears to be Gerhardt 1924). Czajka (1963) also largely an opportunistic occurrence, a especiallyimportant describedan instancewhere E. furcata larger or faster individual overpower- because another spideris a caught a female ,apparently by ing another in a chance encounter. mimicking the courtship web vibra- There are at least a few spider , potentialpredator as well tions of a male of the victim'sspecies. however, for which araneophagy (pre- More recently,Mimetus maculosus dation on other spiders) is routine as potential prey from Australiaand Mimetussp. from (e.g., Jackson and Poulsen 1990). Some (Jackson and White- of these species employ strategies based house 1986) have beenshown to catch on deceit of their spider prey. In this Aggressive , where a preda- other spiders by using deceptive vi- article, I use the images of deception, tor seems beneficial to its prey, is a bratingsignals (Figure1). The deceiv- mimicry, and trickery to convey the ploy sometimes used by araneophagic ers ease onto webs, then transmitsig- functional significance of a predator's spiders. An aggressive mimic might, nals to their intended victims by behavior and not to imply cognition. for example, imitate an that is pulsatingtheir bodies up and down on Use of deceit by araneophagic spiders the intended victim's prey. In this the web and by pluckingand tugging may be especially important because way, an aggressive mimic can gain on the silk with their legs in a variety another spider is a potential predator control over its prey's behavior. The of ways, apparently mimicking as well as potential prey. situation becomes even more com- strugglesof small insects in the web. Approximately 34,000 species of plex when an araneo-phagic spider The mimetids illustrate several spiders have been described and interacts with another spider that is points that apply more generally to grouped into 105 families (Cod- both potential prey and potential aggressive mimic spiders. First, the dington and Levi 1991). Spiders are predator. Of the araneophagic spe- signalingbehavior of aggressivemim- often informally separated into two cies, the aggressive mimics are a small ics is complex. Mimetidsperform sev- behavioral groups: the web builders minority found only in five distantly eraldifferent vibratory behaviors, and, and the cursorial spiders (Foelix 1982). related families. by varyingthe sequencein which they Web builders erect silken webs and performthese behaviorsand the char- wait for their prey to arrive. In con- Pirate spiders as acteristicsof each behavior(e.g., am- and of trast, cursorial species ambush or stalk aggressive mimics plitude speed leg movement), and chase down their prey without they can transmita complex arrayof using webs. But araneophagic species Although pirate spiders (Mimetidae) vibrations across the web to the host tend to be behavioral nonconform- are well known as web-invading spider (Jackson and Whitehouse ists; they fail to fit simply into either of araneophagic spiders (Foelix 1982), 1986). these traditional behavioral groups. for only a few species from this cos- Second, the basic principles that mopolitan family are details known govern intraspecific communication about behavior. Ero furcata, a Euro- also govern interactionsbetween spe- Robert R. is an associate pean mimetid, is a frequently cited cies duringaggressive mimicry. When Jackson profes- A sor in the Zoology Department,Univer- example of an aggressive mimic. animalscommunicate, one individual sity of Canterbury, Christchurch,New member of this species moves onto (the sender) indirectly manipulates Zealand. ? 1992 American Institute of other spiders' webs, where it jerks on another individual (the receiver) by Biological Sciences. the web, apparently mimicking the providing a specializedstimulus (the

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This content downloaded from 185.2.32.89 on Fri, 20 Jun 2014 00:31:39 AM All use subject to JSTOR Terms and Conditions signal)to which the receiverresponds (see Dawkins and Krebs 1978). In aggressive mimicry systems of spi- ders, a predatorprovides another spi- r: der species,its prey,with a signal. But _W in this instance,the predatorattempts to elicit a responsethat benefits itself r-....~ ~~.. I and not the prey. Whetheror not the receiverbenefits in a communication system is an important question be- .r. IP cause the evolution of the receiver's / behavior is easy to account for if it I~~ benefits, but more difficult if it does I~~~ not. The function of the signal, how- ; ever, refers only to how the signal benefits the sender. Third, mimetids, like all web-in- vading aggressivemimic spiders that have been studied in detail, are not limited to using aggressive mimicry (Jacksonand Whitehouse 1986). In- stead, they are versatile predators (Curio1976) whose tacticsdepend on the circumstances (see Dominey Figure1. Mimetusmaculosus (above, facing down, ventral view), having attacked and 1984), and so the tactics are consid- killedanother spider, Eriophora pustulosa (below, facing right, ventral view), wraps eredto be conditionalpredatory strat- its victimup in silk. egies. Mimetids, in addition to catch- ing the spidersin their own webs, also steal insects from other spiders'webs ever,adhere to cribellatewebs and are pholcid that buildsa nonstickydome- (klep-toparasitism)and open egg sacs less efficient as predatorsthere. Some shaped web and, like other pholcids, to feed on the victim spider's eggs other aggressivemimics are more ef- has legs that are especially long rela- (oophagy). These behaviors are dis- fective when invadingcribellate webs tive to the body. When prey contacts tinctly different from araneophagic than when invadingecribellate webs. the web, P. phalangioidesuses its long aggressivemimicry because no signal- How mimetidsand other web-invad- legs to wrap the prey up with silk ing is associated with them. ing spiders avoid adhering to sticky while keepingits body distantand out Fourth, the characteristicsof the webs is not known. of harm'sway. invaded web largely determine how Except for salticids, which will be However, P. phalangioides is not effective an aggressive mimic is at discussed later, spiders do not have simply a predator that uses its own catching the web's resident. Spider acute vision. Typical web-building web. Like Mimetus, P. phalangioides webs varygreatly in shapeand design, spiders rely primarily on web-borne invades alien webs and practices ag- from two-dimensional orb webs to vibrationalcues to detect and locate gressive mimicry and also eats the sparselyspun three-dimensional space prey. A web invader, also without resident spider, insects in the alien webs to thickly woven sheet webs acute vision, relieson vibrationalcues web, andthe victimspider's eggs (Jack- (Foelix 1982). Some spiders, called in the alien web. But because webs son and Brassington1987). cribellates,build sticky webs by coat- may differsignificantly in their vibra- Unlike Mimetus, P. phalangioides ing structurallines with fine threads tional characteristicsdue to structural adheres to both cribellate and fromthe cribellum,a specializedspin- diversity,web invadersare limited as ecribellatesticky webs. Therefore,P. ning plate with minute spigots. Other to the range of web types they can phalangioidesis moreefficient at catch- spiders,called ecribellates, build sticky exploit. This sensory factor appar- ing prey on nonsticky than on sticky webs by secretingfrom spigots on the ently limits most aggressivemimics to webs, and most efficient of all when spinneretsadhesive fluid to form glue being effective as predators on a re- on its own web (Jackson and dropletsalong the threads.Webs with- stricted range of web types (Jackson Brassington 1987). Nevertheless, P. out eitherform of glue are referredto 1986). phalangioidescan catch prey on both as nonsticky, although all types of sticky webs. With its long maybe adhesiveto someextent (Hallas Both a web builder and a legs, P. phalangioidesappears to tip- and Jackson 1986). web invader toe across the sticky web, minimizing Mimetids are most effective when contact with the sticky threads (Fig- invadingthe space and orb webs cre- Research on phalangioides ure 2). Also, by grooming its legs ated by ecribellates (Jackson and (Jacksonand Brassington1987) illus- frequently, P. phalangioides can re- Whitehouse 1986); they do not ad- tratesthat an individualspider may be move any sticky silk that accumu- here to the glue on these most fre- both a web builderand a web invader. lates.Another key to P. phalangioides' quentlyinvaded webs. They do, how- P. phalangioides is a cosmopolitan success at invading sticky webs ap-

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This content downloaded from 185.2.32.89 on Fri, 20 Jun 2014 00:31:39 AM All use subject to JSTOR Terms and Conditions a.__ R - If Zealand illustrates that an ..;,. X. _ gnaphosid, can * araneophagic web-invading spider be both a web builder and a cursorial * *".. predator. Most gnaphosids are insec- "*' -1 e ;F . . X* \jh'. \ tivorous hunters. T. erebus, like typi- _0 - ow.,. Oe1\ \\ cal gnaphosids, generally hunts prey f in the open, completely away from 4.-leX4 webs. However, an individual T. lll erebus may also build a nonsticky web and, in addition, invade the webs I of other spiders. i.', While in an alien web, T. erebus A - practices aggressive mimicry by mak- '.I ing vibratory signals (Figure 4), and it . . may also steal prey or eat eggs. Unlike - , JbV mimetids and T. erebus ? .< Argyrodes, A2 k gets stuck on ecribellate sticky webs. i]s- i. of' T. erebus is most efficient at catching prey on cribellate sheet webs, a type of web on which the previously discussed web invaders are especially inefficient. T. erebus has yet another trick, one 2. Pholcus across cribellate Figure Long-legged phalangioides (right)tiptoeing sticky that is unknown among other web web of Badumnalonginquus (lower left) on which it preys. Both spidersare from New Zealand. invaders. After killing and eating the resident spider, T. erebus often stays in the funnel webs of one of its com- pears to be its own silk. While in alien some species of Argyrodes (Vollrath mon victims, Segestria (species unde- sticky webs, P. phalangioides spins, 1984). The most details are known for termined), and uses the web to catch laying its own nonsticky silk over the Argyrodes antipodiana, a New additional prey (Jarman and Jackson other spider's sticky silk, thereby mak- Zealand species with pronounced 1986). ing a nonsticky walkway for itself. predatory versatility (Whitehouse 1986), even though it feeds primarily Webbuilder and prey stealer by practicing various forms of klep- toparasitism. Most spiders in the family Although A. antipodiana builds a build sticky ecribellate space webs web of its own, it appears to use its and use these webs to catch prey, web only infrequently as an insect generally staying out of other spiders' snare. Instead, its web seems to be webs. However, certain species of used primarily as a base from which to Argyrodes, a large cosmopolitan ge- make forays onto the host spider's nus of small-bodied theridiids, also web. A. antipodiana usually mini- routinely enter the webs of other spi- mizes contact with the host's web, ders. The best known species of web- staying primarily on its own silk lines, invading Argyrodes are kleptopara- which extend from its own to the sites in the webs of much larger host host's web. In this way, A. antipodiana spiders (e.g., Vollrath 1979a). might reduce risk of detection by the Besides taking insect prey from the host spider. Sometimes, however, A. host spider's web, some species of antipodiana enters alien webs and Argyrodes also feed with the host, on catches small spiders (e.g., juveniles the same prey item. After detecting of the host species in the host species' web vibrations made by the host while web) by using vibratory aggressive wrapping prey (Vollrath 1979b), mimicry. A. antipodiana is more ef- Argyrodes moves stealthily into posi- fective as a web invader (kleptopara- tion to take its meal from close to the site and araneophagic predator) when host's mouth (Figure 3). Argyrodes on sticky ecribellate space or orb webs can also its of and is less effective on other types of modify style stealing 3. (arrow), in to in condi- webs. Figure Argyrodesantipodiana prey response changes a small kleptoparasiticspider, feeds be- tions such as prey size and host spider side the mouth of its much larger host, behavior (Cangialosi 1991). Web builder and prey stalker Eriophora pustulosa, on an insect cap- In addition to kleptoparasitism, tured and wrapped up by the host. Both araneophagy appears to be an impor- A recent study of Taieria erebus spiders are from New Zealand. Photo: tant part of the predatory strategy of (Jarman and Jackson 1986), a New Simon Pollard.

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This content downloaded from 185.2.32.89 on Fri, 20 Jun 2014 00:31:39 AM All use subject to JSTOR Terms and Conditions Web-invading I. jumping spiders Most spiders, having small eyes with simple retinas, have poor eyesight. Jumping spiders (Salticidae) are ex- ceptions. With their large eyes and complex retinas (Figure 5), salticids have acute vision (Blest 1985). All salticids appear to be cursorial insec- tivores, but some species are Also araneophagic web invaders. Numerous salticids are known to leap or walk into webs (e.g., Robinson and Valerio 1977). But only ten spe- cies of salticids (from four genera), all d from the subfamily (Wanless 1984), are known to prac- tice vibratory aggressive mimicry (Table 1). Each of these ten salticid aggressive mimics is a versatile preda- tor that catches prey outside of webs by cursorial hunting, invades webs where it uses aggressive mimicry and f catches the resident spider species (Fig- ure and also takes insects 5), (Figure - 6) and the resident spider's eggs from qb-t the alien web. Each species of Figure4. Taieriaerebus (facing left) plucks with left leg II (arrow) while standing on also builds a nonsticky prey-catching a cribellatesheet web of Badumnalonginquus. Detritus on web includes remainsof web. insect prey of B. longinquus and shed exoskeletons of B. longinquus juveniles. Each web-invading spartaeine salticid catches on all prey efficiently web-invading spartaeine salticids are fluttering its legs and palps (Figure 7), of the different of webs ex- types not restricted to certain web types as and twitching its abdomen up and the nonsalticid web invad- ploited by are the nonsalticid aggressive mimics. down. Duration, rate, amplitude, and and Hallas There ers (Jackson 1986c). First, the spartaeine salticids are combinations of these behaviors vary, to be three reasons the appear why versatile in locomotion. Unlike other with almost any combination of the web-invading spiders and apparently spider's eight legs and two palps mov- Table 1. Salticidsthat practice vibratory uniquely among spiders, the spartae- ing at the same time. aggressive mimicry (Jackson 1990a,b, ines can walk across both cribellate R. S. Wilcox and I have worked Jackson and Hallas 1986a,b). and ecribellate sticky silk without get- together in the field and the labora- ting stuck (Jackson 1986). Second, the tory to record the different vibrations Species Location spartaeines, having acute vision, are Portia makes when using these vari- adonis not restricted to interpreting web vi- ous behaviors and to demonstrate that Brettus cingulatus brations to detect, identify, and locate these vibrations are responsible for Gelotia prey on webs as are the nonsalticids the prey spider's response to Portia.' (Jackson and Blest 1982). We detect web vibrations with a gal- Southern Cyrba algerina Europe Third, the spartaeines have a com- vanometer connected by a stylus to a Cyrba ocellata Sri Lanka, plex and finely tuned predatory strat- web, record these vibrations on an FM , egy. Compared to nonsalticid web tape recorder, and, after analog-to- , and invaders, the spartaeines seem to be digital conversion, analyze the signals capable of producing a greater variety with a computer. Signals are played of effective signals for tricking differ- back from the computer through a Portia africana Kenya ent victim species. They combine and power amplifier to a coil to control Portia schultzi vary signals more extensively than do the movement of a small magnet posi- other aggressive mimic spiders. The tioned on the web. This methodology Portia albimana Sri Lanka signal output variation may enable an is analogous to the system Wilcox has Sri Lanka and aggressive mimic to finely control the used in communication studies of responses of each particular victim spider. 1R. S. Wilcox and R. R. Sri Lanka, Portia, the most thoroughly stud- Jackson, 1992, unpub- Malaysia, lished results. State University of New York, and Australia ied spartaeine , makes signals on Binghamton, and University of Canterbury, its victim's web by plucking, striking, New Zealand.

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This content downloaded from 185.2.32.89 on Fri, 20 Jun 2014 00:31:39 AM All use subject to JSTOR Terms and Conditions 1986). Highly flexible signaling, acute vi- sion, and the ability to avoid sticking to cribellateand ecribellatewebs ap- pear to enable salticidsto exploit suc- cessfully a much wider range of web spider species than other aggressive mimic spiders. Cause-and-effectrela- tions during the evolution of salticid characteristicsmust have been com- plex and may be ultimatelyunknow- able. However, acute vision, which has evolved uniquely in the salticids, may have been the centralfactor. The abilityto move about freelyon diverse types of webs and to signal flexibly to various types of spiders would have brought obvious advantagesto a spi- der that could use a sensory modality that was independentof web dynam- ics. These abilities would apparently be of less use to a spider that could only interpretweb vibration (Jackson Figure 5. Brettus cingulatus, a web-invading salticid from Sri Lanka, feeds on an Achaearaneasp. capturedin a stickyecribellate space web. B. cingulatus,like all and Blest 1982). salticids,has largeeyes and acutevision. Specializedaraneophagy away water striders, aquatic insects that sponse from the potential victim. An from webs make specializedripple signals on the appropriateresponse from the victim Studies of T. erebus and P. fimbriata water surface (Wilcox 1979). might be localized movements (e.g., illustrate that web-invading spiders In encounters with some of their pivoting and using forelegs to tug on may also use trickeryto catch spiders more common victim species, Portia the web) or a slow approach toward away fromwebs. Both of these spiders appear to use certain signals. But for the signalingPortia; to move away or are specialists at catching cursorial many of their other victims, they ap- to approach too rapidly would be salticids (Jacksonand Hallas 1986a, pear to use trial and error.2 After inappropriateresponse. No other spi- Jarman and Jackson 1986). Strictly successively trying different signals, ders have been shown to use trial and cursorial salticids do not spin prey- Portia species continue to use only error, and there are only a few other catching webs, but they do spin silk those that elicit an appropriate re- examples of an using shelters (nests), which are usually learningas part of a system of deceiv- densely woven, tubularin shape, and 2Seefootnote 1. ing, then catching, prey (see Mitchell not much larger than the spider in- side. A salticid that finds a conspecific insidea nest may court or threatenthe resident spider by making vibratory signalson the silk (Jackson1982a). T. erebus and P. fimbriata respond to the nests of salticids by makingvibratory signals (nest probing;Figure 8). They then grab their prey when it pokes its front end out of the nest. T. erebus may also enter the nest to attack a pacified female salticid. P. fimbriata has a special method for catchingsalticids out in the open, away from their nests. This trickery, known as cryptic stalking, is not an example of aggressive mimicry. The predator capitalizes on its unusual Figure6. Portiaschultzi, a web-invadingsalticid from Kenya, in a largecommunal appearance;its markings,tufts of hairs, web of Stegodyphus mimosarum, a social spider. P. schultzi captured, and is now and long, spindly legs make this spi- feedingon, a mothin the stickycribellate web, whilesocial spiders are preoccupied der resemble detritus. This cryptic catchinginsects elsewhere in the web. appearance, enhanced by a slow,

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This content downloaded from 185.2.32.89 on Fri, 20 Jun 2014 00:31:39 AM All use subject to JSTOR Terms and Conditions 10c) also goes down guylinesonto the leaves and makes the leaf rock by suddenly flexing its legs, apparently simulatingthe courtshipof Euryattus males (Jackson and Wilcox 1990). We call this behaviorsuspension nest probing.Euryattus females that come *up-- out of their leaves when courted by P. fimbriata are eaten. Nest probing,cryptic stalking, and suspension-nest probing by the P. fimbriata do not de- pendon priorexperience with salticids as prey. Naive, laboratory-rearedP. fimbriata perform these behaviors immediatelywhen tested for the first time with salticid prey, and Portia from other populations and species Figure7. Portiafimbriata (facing left, ventral view), from Australia, on an alienweb neverperform these behaviors,even if (silkdoes not show up in photograph).Portia makes aggressive mimicry signals in a they are rearedin the continual pres- varietyof ways. In this instance,Portia reaches forward with one palp and plucks ence of salticid prey (Hallas 1988, slowlyon a strandof silk. Jackson and Wilcox 1990). choppygait, probablyhelps protect P. P. fimbriata or the other species of fimbriataagainst its own visuallyhunt- Portia studied. Formost spiders,the notion that male ingpredators and conceals Portia from Euryattus females are unusual courtship behavior functions prima- its potential prey. In cryptic stalking, salticids because,instead of makinga rily as a defense against predatory P. fimbriatamoves especiallyslowly, tubularsilk nest,they suspend a rolled- conspecificfemales does not stand up pulls its palps back and out of its up dead leaf by heavy silk guylines to close scrutiny (e.g., Jackson and prey'sview (Figure9a), and freezesif (Figure 10a) from a rock ledge, tree Pollard 1990) Females of some spe- the salticidturns to face it (Figure9b). trunk, or the vegetation in the forest cies have become behaviorally spe- Eventually, P. fimbriata approaches and use the leaf as a nest (Jackson cializedat catchingconspecific males. the salticidfrom behind, then swoops 1985). Euryattusmales (Figure 10b) Forexample, Araneus pallidus spins a down to kill it (Figure9c). P. fimbriata go down guylines onto leaves and prey-captureweb and usually feeds stalks no other prey in this way. court by suddenly flexing their legs on insects,but femalesare also skillful Althoughseveral populations of five and making the leaf rock back and at catching males during mating speciesof Portiahave beenstudied, no forth. Euryattus females then come (Grassholf1964). The male is smaller population other than P. fimbriatain out of their leaves to mate with or than the female, and he must move Queensland,Australia, practices these drive away the males. under the female's abdomen to mate. two special salticid-catchingmethods Unlike any other Portia studied,P. While the male mates with her, the (nest probing and cryptic stalking). fimbriata from Queensland (Figure female slowly pulls out a band of silk The habitat in which this particular Portia lives is unique among those D."...... studied in having a superabundance of cursorialsalticids. Apparently,the Queens-landP. fimbriata'spredatory behavioris specially adapted to a lo- cally abundantprey.

A behavior specific to a single prey A studyof the interactionsbetween P. fimbriataand Euryattus (species un- known) illustrates that an araneo- phagic spider may evolve a prey-spe- 4.1ti,. cificpredatory behavior for use against I even a single species. Euryattus is * sympatric with P. fimbriata in Figure8. QueenslandPortia fimbriata, an araneophagicsalticid, on the nest of a Queensland but is not known to be femaleof anothersalticid species, Tauala lepidus (inside nest, right), makes vibratory sympatricwith other populations of signalsby suddenlyflexing legs.

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This content downloaded from 185.2.32.89 on Fri, 20 Jun 2014 00:31:39 AM All use subject to JSTOR Terms and Conditions sequences of P. labiata and P. schultzi (Jackson and Hallas 1986a). Females of these species, unlike the females of most salticids, have distinct displays by which they solicit a male. Recently mated females are unlikely to mate again; nevertheless, they readily per- form these displays. Even subadult 1% females, which cannot mate, perform these displays, apparently mimicking receptive adult females in these in- a stances. If a male mounts a subadult female, she also may try to kill the male while he attempts to copulate. Males of a few species, such as Araneus diadematus, may even feed themselves deliberately to their mates. In this way, the mother of the male's future offspring gets a meal and, by providing this meal, the male may contribute to his progeny's well-be- ing. Therefore, these males may be- have in a way that facilitates, rather than defends against, cannibalism (Elgar and Nash 1988; but see Gould 1984).

Behavioralcomplexity When discussing ants, E. 0. Wilson (1971) suggested that "a group of species sharing common descent can be said to have truly radiated if one or ' .-^ more species is a specialized predator on others" (p. 2). By this criterion, spiders have truly radiated: an assort- ment of spider species has evolved c specialized methods of preying on Figure9. a. Queensland Portia fimbriata (right) crypticallystalking another salticid other spiders. Among the most strik- (left). Note that the Portia's palps are pulled back. b. The Portia freezes when the ing characteristics of araneophagic salticid turns around. The salticid, apparentlynot recognizing Portia as a predator, spiders are behavioral complexity, later turns and walks slowly away. c. The Portia (facing right) feeds on salticid after variable signal output, and pro- crypticallystalking it, moving over it from behind, then swooping down to grab it. nounced predatory versatility, gener- Portia's are around the dorsal of posterior carapace prey. ally more complex predatory reper- toires than are known among other with one of her rear legs, then sud- by making twist lunges: the female spiders. denly wraps up and eats the male. suddenly rotates around with fangs All of the aggressive mimic spiders Some web-invading spiders also open, grabshold of and kills the male, studied take spiders ranging from prey on conspecifics. The females of then eats him. smaller than to considerably larger two speciesof web-invadingsalticids, Males do not appear to be willing than themselves. The special prob- P. labiata and P. schultzi, for ex- victims. Instead, P. labiata and P. lems facing a spider that attempts to ample, are known to have predatory schultzimales are exceedinglyskittish prey on another spider, especially a behaviorspecific to courtingand mat- suitors comparedwith most salticids, spider of similar or larger size, may ing conspecific males (Jackson and being prone to run and leap away help account for the complexity of the Hallas 1986a). When salticids mate, when the female moves even slightly. behavioral repertoires: the tables may the male usually mounts the female. Interestingly,P. fimbriatafemales do be turned and the araneophagic preda- All species of Portia studied are un- not twist lunge,and P. fimbriatamales tor may become its intended meal's usual in that the female usually drops are not especially prone to run and own meal. The fine control of variable on a dragline after the male mounts leap away from females (Jackson signals may be crucial in enabling the and the pair mateswhile suspendedin 1982b). aggressive mimic to gauge its attack mid-air. While suspended, P. labiata There may also be elements of ag- before it is itself attacked by the in- and P. schultzi females attack males gressivemimicry during the courtship tended victim.

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This content downloaded from 185.2.32.89 on Fri, 20 Jun 2014 00:31:39 AM All use subject to JSTOR Terms and Conditions Aggressive mimics are only one heavily on particular prey species has among many predators for the victim- parallels in discussions of Batesian ized spiders; other enemies such as mimicry. A Batesian mimic is a palat- birds and parasitoid wasps (Bristowe able species that derives protection 1941) are probably more important from potential predators by resem- for most species. It may be important bling aposematic species, which are that spiders practicing aggressive mim- conspicuously marked and unpalat- icry do not prey too heavily on any able. Batesian mimics are apparently particular prey species. Otherwise, successful only if relatively rare prey species might have evolved effi- (Turner et al. 1984). cient means of avoiding predatory Perhaps behavioral complexity is deceit and exploitation. an important way for aggressive mimic Is there any evidence that prey spe- spiders to appear rare to their prey. cies have evolved defenses against a Because the prey spider receives dif- aggressive mimics? The best example ferent stimuli from the predator at may be from interactions between P. different times, it might not perceive fimbriata and Euryattus (Jackson and accurately the predator's abundance. Wilcox 1990). While P. fimbriata is Also, by using a variety of signals and approaching, Euryattus females some- feeding methods, the aggressive mimic times come out of their rolled-up spider can exploit a wide spectrum of leaves, and they suddenly and vio- prey, reducing the frequency of inter- lently strike, leap at, or charge toward action with any one prey species. P. fimbriata. Euryattus may bang head on into Portia and knock P. fimbriata Acknowledgments away at the end of a leap; after this I thank encounter, Euryattus swings down on Philip Taylor, Mary its dragline, then climbs back to the Whitehouse, and Tracey Robinson for leaf. Once attacked, P. fimbriata al- their help during the preparation of ways gives up, and Euryattus sur- the manuscript and Simon Pollard for vives. the photograph used for Figure 3. The From observing thousands of inter- research reviewed was supported by actions between P. fimbriata and many grants from the National Geographic different species of salticids (Jackson Society and grant BNS86-17078 from and Hallas 1986a), it is evident that the US National Science Foundation. Euryattus is more efficient than other salticids at recognizing and defending Referencescited itself a P. against stalking fimbriata. Abrams, P. A. 1986. Is predator-prey coevolu- Laboratory tests provided corrobora- tion an arms race? Trends Ecol. Evol. 1: tive data: P. fimbriata caught 108-110. Jacksonoides queenslandica, another Blest, A. D. 1985. The fine structure of spider Queensland salticid on which it is photoreceptors in relation to function. Pages 79-102 in F. G. Barth, ed. Neurobiology of known to prey, more efficiently than . Springer-Verlag, New York. it caught Euryattus (Jackson and Bristowe, W. S. 1941. The Comity of Spiders. c Wilcox 1990). Frequent by vol. 2. The Ray Society, London. P. fimbriata on Euryattus appears to Figure 10. a. Euryattus sp. female, a Cangialosi, K. R. 1991. Attack strategies of a effects of avail- have resulted in Euryattus evolving salticid from Queensland (Australia),on spider kleptoparasite: prey her a dead leaf ability and host colony size. Anim. Behav. special abilities to recognize and de- nest, rolled-up suspended from vegetation by silk guylines. b. 41: 639-647. fend itself against this predator, sug- Coddington, J. A., and H. W. Levi. 1991. Sys- Euryattussp. male (facingleft) on the leaf these two tematics and evolution of spiders (Arnaeae). gesting that species may of a conspecific female, in courtshippos- have been involved in a coevolution- Annu. Rev. Ecol. Syst. 22: 565-592. ture:body raised, abdomenflexed down, Curio, E. 1976. Ethology of Predation. Springer- ary arms race (Abrams 1986). and legs archedout. By sudddenlyflexing Verlag, New York. Recent studies are consistent with his legs, the male makes the leaf rock Czajka, M. 1963. Unknown facts of the biology coevolution. P. fimbriata is absent, back and forth. c. Queensland Portia of the spider Ero furcata (Villers) but Euryattus present, in a second fimbriata (facing right) on the leaf of a (Mimetidae, Araneae). Pol. Pismo Entomol. 33: 229-231. Queensland habitat which is only ap- Euryattus sp. female, simulating court- ship of Euryattus sp. male. Dawkins, R., and J. R. Krebs. 1978. proximately 15 km away from the signals: information or manipulation? Pages habitat where Euryattus and P. 282-309 in J. R. Krebs and N. B. Davies, fimbriata are sympatric. In tests using ciently than sympatric Euryattus.3 eds. Behavioural Ecology: An Evolutionary UK. laboratory-reared spiders, allopatric The notion that it is advantageous Approach. Blackwell, Oxford, for mimics not to too Dominey, W. J. 1984. Alternative mating tac- Euryattus only rarely evaded or at- aggressive prey tics and evolutionarily stable strategies. Am. tacked stalking P. fimbriata, and P. Zool. 24: 385-396. fimbriata caught allopatric more effi- 3Seefootnote 1. Elgar, M. A., and D. R. Nash. 1988. Sexual

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This content downloaded from 185.2.32.89 on Fri, 20 Jun 2014 00:31:39 AM All use subject to JSTOR Terms and Conditions cannibalism in the garden spider Araneus aggressive mimic from Sri Lanka. N. Z. J. fimbriata and Euryattus sp., jumping spi- diadematus. Anim. Behav. 36: 1511- Zool. 17: 475-482. ders from Queensland. Behav. Ecol. 1517. Jackson, R. R., and A. D. Blest. 1982. The Sociobiol. 26: 111-119. Foelix, R. F. 1982. Biology of Spiders. Harvard biology of Portia fimbriata, a web-building Jarman, E. A. R., and R. R. Jackson. 1986. The University Press, Cambridge, MA. (Araneae, Salticidae) from biology of Taieria erebus (Araneae, Gerhardt, U. 1924. Weitere studien uiber die Queensland: utilization of webs and preda- Gnaphosidae), an araneophagic spider from Biologie der Spinnen. Archiv fiir Naturgesch tory versatility. J. Zool. (Lond.) 196: New Zealand: silk utilisation and predatory 90: 85-192. 255-293. versatility. N. Z. J. Zool. 13: 521-541. Gould, S. J. 1984. Only his wings remained. Jackson, R. R., and R. J. Brassington. 1987. The Mitchell, R. W. 1986. A framework for discuss- Nat. Hist. 93: 10-18. biology of (Araneae, ing deception. Pages 3-40 in R. W. Mitchell Grassholf, M. 1964. Die Kreuzspinne Araneus ): predatory versatility, and N. S. Thompson, eds. Deception: Per- pallidus: ihr Netzbau und ihre araneophagy and aggressive mimicry. J. spectives on Human and Nonhuman De- Paarungsbiologie. Nat. Mus. 94: 305-314. Zool. (Lond.) A 211: 227-238. ceit. State University of New York Press, Hallas, S. E.A. 1988. The ontogeny of behaviour Jackson, R. R., and S. E. A. Hallas. 1986a. Albany. in Portia fimbriata, P. labiata and P. schultzi, Comparative studies of Portia, araneophagic Robinson, M. H., and C. E. Valerio. 1977. web-building jumping spiders (Araneae: web-building jumping spiders (Araneae, Attack on large or heavily defended prey Salticidae). J. Zool. (Lond.) 215: 231-238. Salticidae): predatory versatility, utilisation by tropical salticid spiders. Psyche 84: Hallas, S. E. A., and R. R. Jackson. 1986. Prey- of silk, and intraspecific interactions of P. 1-10. holding abilities of the nests and webs of africana, P. albimana, P. fimbriata, P. Turner, J. R. G., E. P. Kearney, and I. S. Exton. jumping spiders (Araneae, Salticidae). J. labiata, and P. schultzi. N. Z. J. Zool. 13: 1984. Mimicry and the Monte Carlo preda- Nat. Hist. 20: 881-894. 423-489. tor: the palatability spectrum and the ori- Jackson, R. R. 1982a. The behavior of commu- . 1986b. Predatory versatility and in- gins of mimicry. Biol. J. Linn. Soc. 23: nicating in jumping spiders (Salticidae). traspecific interactions of spartaeine jump- 247-268. Pages 213-247 in P. N. Witt and J. S. ing spiders (Araneae, Salticidae): Brettus Vollrath, F. 1979a. Behavior of the Rovner, eds. Spider Communication: adonis, B. cingulatus, Cyrba algerina and kleptoparasitic spider Mechanisms and Ecological Significance. Phaeacius sp. n. N.Z.J. Zool. 13: 491-520. (Araneae, Theridiidae). Anim. Behav. 27: Princeton University Press, Princeton, NJ. . 1986c. Capture efficiencies of web- 515-521. .1982b. The biology of Portia fimbriata, building jumping spiders (Araneae, . 1979b. Vibrations: their signal func- a web-building jumping spider (Araneae, Salticidae): is the jack-of-all-trades the mas- tion for a spider kleptoparasite. Science Salticidae) from Queensland: intraspecific ter of none? J. Zool. (Lond.) A 209: 1-7. 205: 1149-1151. interactions.J. Zool. (Lond.) 196:295-305. Jackson, R. R., and S. D. Pollard. 1990. In- . 1984. Kleptobiotic interactions in in- . 1985. The biology of Euryattus sp. traspecific interactions and the function of vertebrates. Pages 61-94 in C. J. Barnard, indet., a web-building jumping spider courtship in mygalomorph spiders: a study ed. 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