Trial‐and‐error derivation of aggressive‐mimicry signals by Brettus and Cyrba, spartaeine jumping spiders (Araneae: Salticidae) from Israel, Kenya, and Sri Lanka

Abstract

Brettus adonis, Brettus albolimbatus, Cyrba algerina, Cyrba ocellata, and Cyrba simoni are spartaeine jumping spiders (Salticidae) that invade other spiders’ webs, make vibratory signals that deceive the resident spider (aggressive mimicry), then attack and eat the spider. The signal‐generation behaviour of each of these five species is investigated in the laboratory. Each species is characterised by flexible predatory behaviour, including use of a trial‐and‐error (generate‐and‐test) algorithm to derive appropriate aggressive‐mimicry signals: first broadcast an array of different signals, then choose particular signals as a consequence of feedback from the prey spider. However, in laboratory experiments, B. adonis and B. albolimbatus relied on trial‐and‐error significantly more often than did C. algerina, C. ocellata, and C. simoni. Maternal effects and variation in experience were minimised because all individuals tested were laboratory‐reared to the second and third generation under standardised conditions. Selection pressures that may have been responsible for evolution of different levels of flexibility are considered.