Behavioural ecology: tool manufacture by naive juvenile crows

New Caledonian crows (Corvus moneduloides) are the most prolific avian tool-users. Regional variation in the shape of their tools may be the result of cumulative cultural evolution--a phenomenon considered to be a hallmark of human culture. Here we show that hand-raised juvenile New Caledonian crows spontaneously manufacture and use tools, without any contact with adults of their species or any prior demonstration by humans. Our finding is a crucial step towards producing informed models of cultural transmission in this species, and in animals in general.     

Behavioural ecology: bees associate warmth with floral colour

Floral colour signals are used by pollinators as predictors of nutritional rewards, such as nectar. But as insect pollinators often need to invest energy to maintain their body temperature above the ambient temperature, floral heat might also be perceived as a reward. Here we show that bumblebees (Bombus terrestris) prefer to visit warmer flowers and that they can learn to use colour to predict floral temperature before landing. In what could be a widespread floral adaptation, plants may modulate their temperature to encourage pollinators to visit.     

Animal mimicry: choosing when to be a cleaner-fish mimic

Mimicry in vertebrates is usually a permanent state--mimics resemble and normally accompany their model throughout the life stages during which they act as mimics. Here we show that the bluestriped fangblenny fish (Plagiotremus rhinorhynchos), which aggressively attacks other coral-reef fish, can turn off the mimetic colours that disguise it as the benign bluestreak cleaner wrasse, Labroides dimidiatus, and assume a radically different appearance. This opportunistic facultative mimicry extends the fangblenny's scope by allowing it to blend into shoals of small reef fish as well as to remain inconspicuous at cleaning stations.