Figure 4
From: Two developmental switch points for the wing polymorphisms in the pea aphid Acyrthosiphon pisum
Histological comparisons of postembryonic flight-apparatus development among all A. pisum morphs. (a) Wingless male; (b) winged male; (c) viviparous wingless female; (d) viviparous winged female; (e) oviparous female; (f) fundatrix. Transverse planes of second to third thoracic segment are shown. Although wingless males do not possess wings, they possess flight muscles. In winged adults, wings were removed before the sample preparations. Ordinal numbers indicate the nymphal stadia (instars). Arrowheads indicate fat cells.