Distribution

Phoneutria spp.: tropical and subtropical regions of South America.
P. nigriventer: northern Argentina to Uruguay, Brazil (Rio Grande do Sul to Rio de Janeiro).

Biology

The paragraphs below refer to the medically most important species P. nigriventer.

a

b

Fig. 4.42 Phoneutria nigriventer.
a In typical defensive posture.
b Carapace with the arrangement of the 8 eyes.

Body length up to 3 cm, leg length 4.5–6 cm, males smaller. Body covered with short hairs. Colouring greyish to brown-grey, chelicerae (venomous fangs) surrounded by red hairs at the base. Light-coloured marking on the upper surface of the abdomen. 8 eyes in 3 rows (2-4-2) (Fig. 4.42b).

Nocturnal. Do not build webs, but rather actively hunt prey. They travel around in their search for prey and in doing so not uncommonly enter human habitations and adjacent sheds or similar buildings. At daybreak they hide themselves, for example in clothes or shoes. If taken by surprise, they do not attempt to flee like most other spiders, but adopt a warning posture, with front legs raised high, erect upper body and raised chelicerae. In this typical defensive posture, the spider copies every movement made by the cause of the disturbance so that it is always facing it directly (Fig. 4.42a). If you approach these spiders too closely, they jump towards you and bite fiercely. Also, if you try to scare them away with a stick or similar object, they will climb up it towards you at lightning speed.

Risk

Lucas (1988) provides an epidemiological summary for Brazil. Of all the accidents with venomous animals recorded at the Instituto Butantan, São Paolo, Brazil, over 40% are caused by spiders alone. Of a total of 1,136 patients with spider bites who were registered there in 1986, the cause is given as Phoneutria for around 60% of the cases. In over 10% of cases a Wandering spider was brought in for identification, and the species P. nigriventer is believed to be responsible for the large majority of the cases of envenoming.

Literature (biological)

Bücherl 1971b, Lucas 1988, Schenberg and Pereira Lima 1978, White et al. 1995

The World Spider Catalog