Food stress prompts dispersal behavior in apterous pea aphids: Do activated aphids incur energy loss?

► Apterous pea aphids lose their red color and become pale when receive low quality food.► Pale aphids walk up to four times more actively than red ones on the same host plant. ► This enables aphids to quickly respond to crowding by walking to neighboring plants. ► Active aphids lose their body weight and energy contents compared to non-active ones. ► Our findings highlight a new shift between reproductive and dispersal phases in aphids.