Hunting Prey With Different Escape Potentials—Alternative Predatory Tactics In A Dune Dwelling Salticid

Abstract

Generalist predators hunt a wide range of prey that possess various characteristics affecting the predators' hunting success (e.g., size, ability to detect the threat and defend against it, potential for escape). Therefore, it can be expected that the predator should flexibly react to different prey characteristics, hunting them in prey-specific ways. For a stalking predator a crucial prey feature is its ability to escape. In this study, the alternative prey-catching tactics of a dune-dwelling salticid Yllenus arenarius Menge 1868 were analyzed. Four naturally eaten prey taxa, two with a high ability to escape (Homoptera, Orthoptera) and two with a low ability to escape (Thysanoptera, larvae of Lepidoptera), were used. Numerous differences found between the tactics indicate that Y. arenarius can not only distinguish between different types of prey, but can also employ specific tactics to catch them. The tactics belong to a conditional strategy and are manifested in alternative: a) direction of approach, b) speed of approach, and c) other prey specific behaviors.

Predatory Encounters of Yllenus Arenarius (Araneae, Salticidae) with Flies (Diptera)

“…There is a very close similarity between the order and presence of particular behavioural units in predatory encounters of Y. arenarius with flies and with other prey characterized by high ability to escape (Homoptera, Orthoptera), which this spider was tested with (BARTOS 2002(BARTOS , 2007(BARTOS , 2008. All behavioural elements observed in this study were also present in experiments with Homoptera and Orthoptera.…”

“…Behaviours specific for Y. arenarius are defined and discussed in BARTOS (2000BARTOS ( , 2007. Movies with selected behaviours discussed in this paper can be seen online (http://maciejbartos.pl/movies/) to enable comparison.…”

“…arenarius with other prey (Homoptera, Orthoptera, Thysanoptera and larvae of Lepidoptera) have been described earlier with particular attention on the spider's predatory versatility (BARTOS 2000(BARTOS , 2002(BARTOS , 2007(BARTOS , 2008.…”

“…Jumping spiders hunt a wide variety of invertebrates and their prey may vary according to many aspects, to mention only the ability to escape or harm the predator. There are numerous examples of conditional predatory tactics characterized by four basic aspects: different direction and velocity of approach to prey, different distances from which the prey is attacked and a variety of other preyspecific behaviours observed during predatory encounters (EDWARDS, JACKSON 1993, 1994BEAR, HASSON 1997;BARTOS 2007). Irrespective of the variety of preyspecific behavioural adaptations, most predatory encounters consist of three primary patterns: orientation, pursuit and capture (FORSTER 1977).…”

“…Y. arenarius is a cryptically-coloured, sit-and-wait predator feeding on a wide range of insects and spiders that inhabit open sand or are blown by the wind onto the dune surface from neighbouring habitats (BARTOS 2004). It was found that the spiders use a conditional hunting strategy manifested in prey-specific jumping distance, speed of approach, direction of approach and other prey-specific behaviours (BARTOS 2002(BARTOS , 2007(BARTOS , 2008). …”