Odour priming of a mosquito-specialist predator's vision-based detouring decisions.

A capacity to execute long detours that are planned ahead of time has cognitive implications pertaining to reliance on internal representation. Here we investigate the detouring behaviour of Evarcha culicivora, an East African salticid spider that specializes at preying on blood-carrying mosquitoes. The findings from our experiments are the first evidence of a salticid making detouring plans based on whether the path chosen leads to more preferred instead of less preferred prey, as well as the first evidence of olfactory priming effects on motivation and selective attention in the context of detouring.

Arthropod Intelligence? The Case for .

Macphail's "null hypothesis," that there are no differences in intelligence, qualitative, or quantitative, between non-human vertebrates has been controversial. This controversy can be useful if it encourages interest in acquiring a detailed understanding of how non-human animals express flexible problem-solving capacity ("intelligence"), but limiting the discussion to vertebrates is too arbitrary. As an example, we focus here on , a spider with an especially intricate predatory strategy and a preference for other spiders as prey.

Influence of seeing a red face during the male-male encounters of mosquito-specialist spiders.

Males of Evarcha culicivora, an East African jumping spider (Salticidae), have bright red faces. Here, we investigated how seeing a red face might influence a male's behaviour during encounters with another male. We applied black eyeliner to conceal the red on a male's face and measured the spectral properties of male faces with and without the eyeliner.

's capacity to decide whether a detour is necessary.

Proficiency at planning is known to be part of the exceptionally complex predatory repertoire of , a genus of jumping spiders (Salticidae) that specialize in preying on other spiders. This includes proficiency at choosing between two detour routes, with only one leading to otherwise inaccessible prey. Less is known about 's proficiency at making strategic decisions pertaining to whether a detour is required or not.

When it looks and walks like an ant.

Some jumping spiders (family Salticidae) bear a striking resemblance to ants, a dangerous type of prey, both in terms of their appearance and in terms of how they move. Recent research has taken important steps toward determining whether predators categorize these spiders as ants on the basis of the way they move.

Representation of different exact numbers of prey by a spider-eating predator.

Our objective was to use expectancy-violation methods for determining whether , a salticid spider that specializes in eating other spiders, is proficient at representing exact numbers of prey. In our experiments, we relied on this predator's known capacity to gain access to prey by following pre-planned detours. After first viewed a scene consisting of a particular number of prey items, it could then take a detour during which the scene went out of view.

Ontogenetic shift in plant-related cognitive specialization by a mosquito-eating predator.

Evarcha culicivora, an East African salticid spider, is a mosquito specialist and it is also a plant specialist, with juveniles visiting plants primarily for acquiring nectar meals and adults visiting plants primarily as mating sites. The hypothesis we consider here is that there are ontogenetic shifts in cognition-related responses by E. culicivora to plant odour.

Convergence between a mosquito-eating predator's natural diet and its prey-choice behaviour.

On the basis of 1115 records of feeding in the field, we can characterize this East African jumping spider (Salticidae) as being distinctively stenophagic. We can also, on the basis of laboratory prey-choice experiments, characterize . as having a specialized prey-classification system and a hierarchy of innate preferences for various categories of mosquitoes and other arthropods.

The execution of planned detours by spider-eating predators.

Many spiders from the salticid subfamily Spartaeinae specialize at preying on other spiders and they adopt complex strategies when targeting these dangerous prey. We tested 15 of these spider-eating spartaeine species for the capacity to plan detours ahead of time. Each trial began with the test subject on top of a tower from which it could view two boxes: one containing prey and the other not containing prey.

Intricate predatory decisions by a mosquito-specialist spider from Malaysia.

Paracyrba wanlessi is a southeast Asian jumping spider (Salticidae) that lives in the hollow internodes of fallen bamboo and preys on the larvae, pupae and adults of mosquitoes. In contrast to Evarcha culicivora, an East African salticid that is also known for actively targeting mosquitoes as preferred prey, there was no evidence of P. wanlessi choosing mosquitoes on the basis of species, sex or diet.

Solving a novel confinement problem by spartaeine salticids that are predisposed to solve problems in the context of predation.

Intricate predatory strategies are widespread in the salticid subfamily Spartaeinae. The hypothesis we consider here is that the spartaeine species that are proficient at solving prey-capture problems are also proficient at solving novel problems. We used nine species from this subfamily in our experiments.

Cross-modality effects of prey odour during the intraspecific interactions of a mosquito-specialist predator.

One of the predictions from evolutionary game theory is that individuals will increase their willingness (i.e., become primed) to escalate aggression when they detect the presence of a limiting resource.

Specialised use of working memory by Portia africana, a spider-eating salticid.

Using expectancy-violation methods, we investigated the role of working memory in the predatory strategy of Portia africana, a salticid spider from Kenya that preys by preference on other spiders. One of this predator's tactics is to launch opportunistic leaping attacks on to other spiders in their webs. Focussing on this particular tactic, our experiments began with a test spider on a ramp facing a lure (dead prey spider mounted on a cork disc) that could be reached by leaping.

A COGNITIVE PERSPECTIVE ON AGGRESSIVE MIMICRY.

We use the term 'aggressive mimic' for predators that communicate with their prey by making signals to indirectly manipulate prey behaviour. For understanding why the aggressive mimic's signals work, it is important to appreciate that these signals interface with the prey's perceptual system, and that the aggressive mimic can be envisaged as playing mind games with its prey. Examples of aggressive mimicry vary from instances in which specifying a model is straight forward to instances where a concise characterisation of the model is difficult.

Olfaction-based anthropophily in a mosquito-specialist predator.

Evarcha culicivora is an unusual salticid spider because it feeds indirectly on vertebrate blood by choosing blood-carrying mosquitoes as preferred prey. Its preferred mosquitoes are Anopheles, the genus to which all human malaria vectors belong. Here, we show that human odour, which is known to be salient to malaria vectors, is also salient to the adults and juveniles of E.

Olfactory search-image use by a mosquito-eating predator.

By choosing blood-carrying mosquitoes as prey, Evarcha culicivora, an East African salticid spider, specializes at feeding indirectly on vertebrate blood. It also has an exceptionally complex mate-choice system. An earlier study revealed that search-image use assists E.

How blood-derived odor influences mate-choice decisions by a mosquito-eating predator.

Evarcha culicivora (Araneae, Salticidae) feeds indirectly on vertebrate blood by choosing, as preferred prey, bloodcarrying female mosquitoes. Mutual mate-choice behavior is also pronounced in this species. Here we show that, when E.

Cross-modality priming of visual and olfactory selective attention by a spider that feeds indirectly on vertebrate blood.

Evarcha culicivora, a jumping spider from East Africa, specialises in feeding indirectly on vertebrate blood by choosing blood-carrying mosquitoes as preferred prey. Previous studies have shown that this predator can identify its preferred prey by sight alone and also by odour alone. Here we investigate how vision and olfaction work together.

Mate-odour identification by both sexes of Evarcha culicivora, an East African jumping spider.

Evarcha culicivora is an unusual salticid spider because each sex actively courts the other and both sexes make distinctive mate-choice decisions. Here we use olfactometer experiments for investigating the ability of each sex to identify potential mates on the basis of odour alone. Test spiders spent more time in the vicinity of opposite-sex conspecific source spiders, regardless of whether or not these source spiders had previously mated, when the alternatives were conspecific individuals of the same sex, juveniles or a control (no odour source).

How cross-modality effects during intraspecific interactions of jumping spiders differ depending on whether a female-choice or mutual-choice mating system is adopted.

An important prediction from game theory is that the value of a resource influences the level to which conflict escalates. Here we use jumping spiders (Salticidae) to consider this prediction in the context of species adopting different mating systems ('female mate-choice' and 'mutual mate-choice'). Our experiments are designed for determining whether the odour of conspecific females, more than the odour of heterospecific females, primes males to escalate conflict with a potential same-sex rival and also whether the odour of conspecific males, more than the odour of heterospecific males, primes females to escalate conflict with a potential same-sex rival.

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).

Cross-modality effects during male-male interactions of jumping spiders.

An important prediction from game theory is that the value of a resource influences the level to which male-male conflict escalates. Earlier experimental studies have shown that the seven salticid species we study here (Bavia aericeps, Euryattus sp., Hypoblemum albovittatum, Jacksonoides queenslandicus, Marpissa marina, Portia africana and Simaetha paetula) determine by sight whether a female is a conspecific or a heterospecific and then escalate the intensity with which they interact (i.

Influence of optical cues from conspecific females on escalation decisions during male-male interactions of jumping spiders.

An important prediction from game theory is that the value of a resource influences the level to which male-male conflict escalates. An earlier experimental study showed that males of Hypoblemum albovittatum, a common salticid in New Zealand, can discern by sight alone whether a female is in the vicinity and that, having detected a female's presence, males escalate (i.e.

Spider heuristics.

Simple heuristics may help explain how even a spider, despite its minute brain, can be disturbingly intelligent. Hutchinson and Gigerenzer suggest that the generalist-specialist distinction (or more accurately the predictability-unpredictability distinction) may be related to a species' level of reliance on simple heuristics, and spider behaviour may present some especially instructive opportunities for investigating these ideas. Daniel Dennett's distinction between Darwinian, Skinnerian and Popperian animals might be useful for discerning the different contexts in which optimality considerations and individual decision making are relevant.