Figure 1
From: Two developmental switch points for the wing polymorphisms in the pea aphid Acyrthosiphon pisum
Schematic diagram of annual life cycle in A. pisum . This species reproduces by thelytokous parthenogenesis in spring and summer under long day length and high temperatures. Males and oviparous females only appear in late autumn and produce fertilized eggs for overwintering. Viviparous females exhibit wing polyphenism, and males exhibit genetic wing polymorphism. Fundatrices and oviparous females are monomorphic and wingless. WD: winged, WL: wingless.