I was under fire last Tuesday. Apparently they don’t stop paint-balling even if there is an ecological survey on, and paintballs hurt. Perhaps I needed some advantageous sixth sense to dodge these projectiles like the wonderful little Winghead Shark. This week we add the words ‘tactical genius’ to super senses, hope you all enjoy.

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Issue #174 - Portia labiata

Kingdom – Animalia

Phylum – Arthropoda

Class – Arachnida

Order – Araneae

Family – Salticidae

Genus – Portia

Species – labiata

Related Species - Portia labiata is one of the seventeen Jumping Spiders found within the genus Portia (1)

Range - Portia labiata is found in forests and scrubland across South East Asia; from India in the East to the Philippines and Indonesia in the West.

The real ‘Spidercide’

Portia labiata is a small brown spider, with females reaching a body length of only a centimetre, with males being about three quarters of the size of an adult female. Like other Jumping Spiders, the large pair of main eyes are the main feature of this arachnid, and when combined with the six smaller eyes dotted around its head gives the spider all round vision. While all Jumping Spiders have good vision, those found within the genus Portia have the most acute eyesight, and even best dragonflies in detecting targets and maintaining focus, although said focus is very narrow and takes far longer to build up an image (2). To aid it in navigating around its environment, P.labiata has rows of bristles on its legs that allow it to detect chemical changes and vibrations in the world around it.

Like the majority of spiders, P.labiata is an obligate carnivore, and while it will feed on insect prey, the preferred prey of all members of the genus Portia are other spiders. Web building spiders are preferred, although the species has no qualms about hunting other jumping spiders, and the size of prey can range up to two times the size of the hunting Portia. Hunting tactics are varied, and can be adapted on the ‘fly’ either through experiences of previous failures, or by detecting and taking advantage of changes in the environment (3). Hunting tactics are usually planned from a vantage point, and may take up to an hour to process before P.labiata begins moving in on its intended victim. When attacked itself, either by predators or its intended victim, P.labiata can shed a leg to sate its attacker, before jumping to safety.

Female Portia spiders set up territories ‘one moult’ before maturing as adults, and mark the edges with draglines, which contain pheromones indicating the strength and age of the spider who set them. Male spiders home in on these draglines, but will actively avoid those that contain the scent of other males, and will make himself known to the female, by standing tall and wave his palps to get her attention. Often the female reacts aggressively, but should the male stand his ground and respond in turn, mating usually occurs, although once complete the female is quick to turn on her mate, and even cannibalise him if he is unable to escape (4). Eggs are laid sometime later on a leaf suspended on top of the female’s web and are guarded by the female until they hatch.

Five Sneaky Portia Hunting Tactics

Portia spiders will pluck the webs of web building spiders to mimic struggling prey in order to attract the web’s host towards it. The Portia spider will at first pluck randomly, but upon finding the correct vibrations to attract its victim, will continue to associate that particular ‘strumming motion’ with that particular species.

Should plucking prove unresponsive, Portia spider may enter their preys web, and slowly advance towards the owner, only moving when the wind blows or another vibration can mask their movements.

Alternatively, if the spider in the web has eggs, Portia may deliberately make its presence known and cause the host to flee in what has been dubbed a ‘Portia panic’ before stealing the eggs for consumption later (5).

Portia spiders also target the Spitting Spider (Family: Scytodidae) which defend themselves by spitting venom. Portia will always attempt to attack from behind or above, unless it’s a female carrying her eggs in her fangs, in which case it attacks from the front, knowing that its prey will have to drop the eggs before defending itself.

When planning an attack on a victim Portia will always choose the most optimum route, even if said route takes it out of the line of sight of its prey and take hours or even days to reach its intended prey.

Bibliography

1 - www.arkive.org

2 - Jackson, R.R.; A.D. Blest (1982). "The distances at which a primitive jumping spider, Portia fimbriata, makes visual discriminations" Journal of Experimental Biolology. 97: 441–445.

3 - Wilcox, S. & Jackson, R. (2002). "Jumping Spider Tricksters". In Bekoff, M.; Allen, C. & Burghardt, G.M. The Cognitive Animal: Empirical and Theoretical Perspectives on Animal Cognition. MIT Press. pp. 27–3

4 - Jackson, Robert R.; Susan E. A. Hallas (1986). "Comparative biology of jumping spiders Portia africana, P. albimana, P. fimbriata, P. labiata and P. schultzi, areanophagic, web-building jumping spiders (Araneae: Salticidae) utilisation of webs, predatory versatility, and intraspecfic interactions". New Zealand Journal of Zoology. 13: 423–48

5 - Wilcox, R. Stimson; Robert R. Jackson (1998). "Cognitive Abilities of Araneophagic Jumping Spiders". In Russell P. Balda; Irene Maxine Pepperberg; Alan C. Kamil. Animal cognition in nature: the convergence of psychology and biology in laboratory and field

Picture References

1 - http://farm8.static.flickr.com/7773/18297500732_27aaa17121.jpg

2 - https://c1.staticflickr.com/6/5346/10071160275_5d67f82bb1_b.jpg

3 - https://c1.staticflickr.com/8/7349/12375745183_8484451310_b.jpg

4 - https://ichef.bbci.co.uk/images/ic/976x549_b/p037zbtz.jpg

This spider is a genius!! Well skilled no doubt at the very least. And thanks to @rockette we go from tactical thinking we go to ‘road train of terror’. Until then though make sure to critic, comment and suggest future issues as well as making sure you check out past issues in Impurest’s Bestiary.

Many Thanks

Impurest Cheese

Want more IGTA? For more cute Jumping Spider antics, click here to see the adorable Zebra Jumping Spider. Or for an animal that can ‘predict the future’ click here to see the tactical Tentacled Snake.