Focus on Behavioral Ecology ACADEMIA 16 No. 2 (30) 2011 mation available. mation how they make decisions based on the infor- and world their perceive they how study to researchers allowing spiders, the cin- for emas miniature up setting involve studies such some surprisingly, Perhaps animals. in processes making decision and learning into research for model good a them make size brain small and vision excellent Their animals. higher many than behavior plex com- more exhibit and mammals, or birds many than eyesight better have butterflies, prettiest the as colorful as are spiders many In better. them reality, apart from the genuinely scary ones, know to get and spiders about more out find to need simply afflicted venom. terrible However, arachnophobia can be cured: creatures’ those the of tales by fuelled panic trigger even and people some disliked, in widely are They cupboard. the behind corners dark in lurk that tures gered by various mechanical stimuli. Their stimuli. mechanical various by gered trig- cuticle their in tensions nests and webs, their or substrate, the by transmitted those airborne, vibrations: of kinds different The sensory world they live in is made up of poor eyesight and are mainly active at night. have species spider described 42,000 over the of majority The arthropods. predatory of hunting techniques hunting accuracy, new great with learn and prey problems,their complex recognize solve to able are spiders many limitations,size brain severe of spite In spiders jumping of behavior the studies Bartos Maciej Dr [email protected] Łódź of University Protection Environmental and Biology of Faculty MaciejBartos Cinema the at Spiders ecology,Spider behavior, learning and o ot epe sies r hiy crea- hairy are spiders people, most To pdr fr a ag ad ies group diverse and large a form Spiders darkness and light In acuity exceeds that of of that exceeds acuity visual their and objects, viewed of configurations complex differentiate to able are they range, UV the in wavelengths ing includ- color, see They stimuli. visual by domi- nated is world whose spiders diurnal of group vision. of acuity low all spiders are limited by not However, behavior. simple the relatively exhibit spiders of majority such As prey. or partner a identify to them allow degree lesser a to and intensity, allow them to notice motion, changes in light not capable of perceiving complex images. They are insects, of those like eyes, simple spiders’ Most individuals. between nication commu- and orientation in role an important play also stimuli chemical perceive to used organs sensory and Eyesight nearby. scuttling or flying insects localize remotely and webs complex construct them helping accurately, signals those perceive to them allow organs sensory receptive extremely There is in fact a large cardinalis jumper ( jumper Cardinal American animals.Pictured: higher many than behavior complex more mammals,exhibit and or birds many than eyesight better have butterflies,prettiest the as colorful as are that spiders of plenty are There Phiddippus Phiddippus )

Keith Stewart/bugsinthenews.info ACADEMIA Focus on Behavioral Ecology

No. 2 (30) 2011 17 Dune jumping spider examining its prey . In o ). Despite this and the fact o Huge eyes, small brain Jumping spiders have an extremely good the corneal lens there is a long tube reach- ing far into the cephalothorax. At the end is magni- front, in lens another with retina, the fying the image times. 1.5 The long, tubular eyes, the narrow retina and the additional lens mean that the spiders are as if looking through a telescope – the image is magni- fied, although the field of vision is very nar- row (approx. 10 order to see an object in full, the spider must spider the full, in object an see to order first examine it closely – scan it bit by bit – and assemble the images to form a whole. The retina has a distinct, narrow V shape of densely spaced receptors, with the arms of the V facing towards the lens. This arrange- ment provides sharp resolution of objects at various distances from the observer, even built is retina The eye. the adjusting without sensitive is layer each cells; of layers four of to a different light jumping spiders to see color. wavelength, enabling that the corneal lens is immobile, making it impossible to look around, jumping spiders have developed a unique muscular system moving the retina inside the cephalothorax while the lens stays fixed. The system of six muscle pairs attached to the surface of the relative- with retina the provides tube visual ly free movement inside the cephalothorax, increasing the visual field to around 60 visual acuity and exhibit highly behavior, even though they have very small complex brains (no larger than a pinhead). Such small a brain size severely limits tional computa- ability and, as a animal’s consequence, behavioral the complexity. It should be remembered that neurons brates are in larger than in vertebrates. There inverte- visual o Extraordinary eyes Despite their name, the most extraordi-

field. Three pairs are secondary eyes; like the eyes of most insects, they are only capa- ble of perceiving changes in light intensity and movement, and they do not allow the spider to recognize complex patterns. This ability is provided by their principal eyes situated at the front of the cephalothorax. When an object appears in the visual field, the spider first notices its movement using the secondary eyes; it then turns round to face it and examine it more closely the using principal eyes. The eyes have important structural several features differentiating them making and eyes secondary from them extremely effective visual organs. Behind many vertebrates, even ones with as good as cats or vision pigeons. This is the - fam ily of jumping spiders (Salticidae), their name to their ability to owing jump to escape enemies or while hunting prey. They the are largest and most diverse ily. spider Although fam- only 60 species spiders of can jumping be found in Poland, there over are 5300 different species worldwide. is worth It noting that the majority have been described by Polish taxonomists, Prof. Jerzy Prószyński, Prof. Wanda Wesołowska, and Prof. Marek Żabka. nary thing about jumping spiders is not ac- tually their ability to jump – which is, after are They spiders. other certain by shared all, truly distinguished by their extremely well developed vision, centered in one of their four pairs of eyes, which represent a unique evolutionary adaptation in the animal king- dom in terms of structure and function. The eyes are all located around the cephalotho- 360 almost an animal the giving rax, Maciej Bartos Maciej Focus on Behavioral Ecology ACADEMIA understanding of the of understanding Research carried out carried Research dune jumping spider jumping dune complexity of spider of complexity in recent years has years recent in brought significant brought behavior.Pictured: progress in our in progress 18

No. 2 (30) 2011 prey its with not only using innate, fixed tactics, but are but tactics, fixed innate, using only not the from ders spi- jumping example, For Zealand. New in team his and Jackson Robert by out carried work of result a as mainly behavior, spider of understanding our in advances nificant them and solve complex tasks. complex solve and them a good ability to use information available to invertebrates in a new light: as animals with see to scientists allowing conditions, trolled con- under decision a or make to required are tasks problem-solving set the are which animals in settings experimental cre- ative and methodology contemporary to use started have researchers that recently ants only is it years, many for studied and been have bees nest Although source. the food between and distance and relative location the as such information complex often diverse, transmit to other each with communicate to able are hymenoptera cial so- certain that out turned it scrutiny closer Under improved. methodology research and knowledge our as changed gradually has – times Cartesian since persisting – view this However, learn. to ability or flexibility ioral behav- no show that animals programmed pre- simple, as regarded been recently until invertebrates. other from out them marking spiders, all of complex most the undoubtedly is – order the in smallest the among – spiders the jumping of paradoxically, behavior But be. must “wiring” latter’s the limited how clear it makes ders brain sizes and structures to their those of jumping spi- comparing mammals; just among even vertebrates, of of groups abilities different cognitive in variation huge is Spider ecology,Spider behavior, learning and n eet er tee ae en sig- been have there years recent In spiders among Primates All invertebrates, spiders included, have included, spiders invertebrates, All genus hunt their prey their hunt genus Portia

Maciej Bartos tive ecology. tive decision making processes, known as cogni- and processing information of analysis the realm of a new branch of ecology combining reproduction? These questions fall under the and survival of chances their maximize to it use and accordingly, it interpret vironment, en- their of element specific their a on focus attention to them for possible it is How environment? the from receive they mation and make decisions analyze based on the wealth of infor- to manage systems nervous question: simple relatively with animals these do how the with faced are we behavior, ent in higher vertebrates. Analyzing pres- be only to thought been had recently until which skill a map, cognitive mental a create to spider the requires here scribed from disappears temporarily assault the of object the and prey, the to direction opposite the in leads route selected the when even pens hap- This prey. the which to it lead eventually will one the select and route a prepare arrangement of its surroundings to plan and it directly. In this scenario it uses the spatial sees its potential prey, but is unable to reach when situations in demonstrated well undetected. prey their approach to them allow to cover this create They motion. air imitate to themselves web detected. Ifthereisnowind,theytwitchthe being from them preventing wind of gusts during only move they unnoticed remain to frequently order in although spider, host They the approach host. the from response a elicit that those selecting frequency intensity, varying and of vibrations of range wide a out sending – code correct the mine prey unknown an of web the entering on signals, mating of set distinctive own its has species each Since strategies. hunting innate using allows this However, moment. suitable a at caught be to itself allowing unawares, intruder the approaches and fooled usually is host The ed by the host as encouragement for mating. interpret- signals sending entering, are they web the of host the of partners sexual ate” “imperson- often – spiders other – prey ous methods. danger- very a hunting hunting in specializes Portia new learn to able also hs sal pdr’ ontv aiiy is ability cognitive spiders’ small These iul il. h bhvo de- behavior The field. visual Portia’s ss ra ad ro t deter- to error and trial uses Portia to capture only certain spiders certain only capture to Portia Portia’s Portia ACADEMIA Focus on Behavioral Ecology

No. 2 (30) 2011 19

n . Oxford University . Press Oxford University Spider Spider behaviour: flexibility Cambridge Press University Biology of spiders. and . versatility We took advantage of recent - achieve de- the at aiming research, preliminary Our In my do really on view, spiders improve

www.maciejbartos.pl Further reading: Foelix R. F. (1996). Herberstein E. M. (2011). ments in computer graphics and projection modern technologies: we constructed a miniature cinema for spiders, animations of virtual prey with varying test projecting characteristics. During the early stages we were unsure whether the attack spiders the would animated prey at stripped of all, most of it its features being to produce forms that never occur in nature. We covered dis- that the animations were attractive to inexperienced spiders with no previous hunting experience; however, they no longer of were interest to older, experienced individuals. Ongoing research is testing for specific features such as body proportions, type of movement, presence of legs, wings or antennae, and head position. Preliminary data analysis shows which characteristics the spiders use to identify prey: the important traits most in distinguishing prey with different abilities to escape are body propor- tions, rather than means of locomotion or the presence of wings. Certain features are key stimuli which fundamentally cumula- a have others response; spiders’ the change tive effect and improve the ability to recog- with combination in and gradually prey nize other traits. communicate to symbols of set a of velopment beto is This completed. almost is spiders, with of stage the by the followed most interesting symbols with known manipulating research: is The to aim of the properties. manipulation discover how spiders cope in a variable envi- based decisions make they how and ronment on diverse, frequently contradictory - informa tion. The results should at least partially help jumping of eyes the through world the see us spiders, and help us understand how their of information variety the process brains tiny perceived through the eyes. closer scrutiny. Moreover, when of some looking least at at that aware not be try should we just them So us. at back right staring are them them! scare to Maciej Bartos Maciej Yllenus arenariusYllenus . Spider cinemas to respond spiders How do inexperienced I have been studying the behavior of - jump signals they prey have potential never differentiate they previously do How encoun- tered? After all, objects? and from enemies inedible they have not been with equipped any kind of “catalogue” to refer to. Even if this was the animalsthe objects all of range sheer the case, in encounter their is environments so huge is that solution the selective only reasonable sensitivity to some features common to all prey from each type. Although the types of fast-moving prey listed above seem very dif- ferent on a superficial level, they do share cer- as be can regarded which characteristics tain escape. to ability prey’s the of indicators likely stage first the during defined were traits Those was the the to issue next enable of research; researchers to manipulate one such character- istic independently of the others. ing spiders for many years, working to define define to working years, many for spiders ing the traits the spiders potential partners from use enemies and to prey, individual differentiate to used recognize and the features easy to is relatively This prey. categorization observe, since different types of prey with dif- ways. different in captured are features ferent I is with work The lab a rat equivalent small – spider jumping of species This tiny spider uses very different strategies strategies different very uses spider tiny This grass- as such prey, fast-moving hunting when or flies, leafhoppers, than hoppers, for those unable to escape, such as caterpillars. The dif- such hunt, the of aspects key involve ferences as speed, of direction approach to the are prey, differences The attack. of distance the and so clearly marked that it is sufficient to watch to establish prey its approaches a how spider not. or escape to able be will prey the whether inex- young, hatching, after soon Furthermore, same the select consistently spiders perienced of types as prey for specific strategy hunting only not that means This individuals. adult do but also innate, behavior is hunting complex recognition prey in used mechanisms the that have a similar basis. visual field o spiders is their excellent visual feature of jumping the spiders with an placed around their acuity. Their eyes are acuity. The true distinguishing almost 360 cephalothorax, providing cephalothorax,