Figure 9
From: Two developmental switch points for the wing polymorphisms in the pea aphid Acyrthosiphon pisum
Schematic diagrams showing the hypothesized relationships between the developmental time in both winged and wingless aphids and the degree of flight-apparatus development. (a) The forked pathway in which wing primordia did not develop at all in any of the developmental stages in wigless morphs; (b) the pathway in which wing primordia once organize and breakdown in wigless morphs. In polyphenic development, the pathway including primordia formation and subsequent context-dependent degeneration (b) may be maintained rather than the pathway without unavailing primordia (a) due to allowing rapid response to environmental cues. FA: flight apparatus, WD: winged, WL: wingless.