Starvation Stress Causes Body Color Change and Pigment Degradation in Acyrthosiphon pisum

Abstract

The pea aphid, Acyrthosiphon pisum (Harris), shows body color shifting from red to pale under starvation in laboratory conditions. These body color changes reflect aphid’s adaptation to environmental stress. To understand the color-shifting patterns, the underlying mechanism and its biological or ecological functions, we measured the process of A. pisum’s body color shifting patterns using a digital imagery and analysis system; we conducted a series of biochemical experiments to determine the mechanism that causes color change and performed biochemical and molecular analyses of the energy reserves during the color shifting process. We found that the red morph of A. pisum could shift their body color to pale red, when starved; this change occurred rapidly at a certain stress threshold. Once A. pisum initiated the process, the shifting could not be stopped or reversed even after food was re-introduced. We also discovered that the orange-red pigments may be responsible for the color shift and that the shift might be caused by the degradation of these pigments. The carbohydrate and lipid content correlated to the fading of color in red A. pisum. A comparative analysis revealed that these reddish pigments might be used as backup energy. The fading of color reflects a reorganization of the energy reserves under nutritional stress in A. pisum; surprisingly, aphids with different body colors exhibit diverse strategies for storage and consumption of energy reserves.

Parental silencing of a horizontally transferred carotenoid desaturase gene causes a reduction of red pigment and fitness in the pea aphid

“…Silencing of CdeB prolonged nymph development duration in the present generation, altered the body weight and age structure, and significantly decreased the total aphid population number. Several studies have suggested that the red pigment could be used as a backup energy source that influences body length, body weight, finding of new hosts, and starvation resistance …”

Learning‐induced switching costs in a parasitoid can maintain diversity of host aphid phenotypes although biocontrol is destabilized under abiotic stress

“…This might include stress conditions that affect resource vulnerability to attack by the consumer, for example through a change in morphology (e.g. stress‐induced changes in aphid body colour that alter their location by predators: Losey, Harmon, Ballantyne, & Brown, 1997; Wang et al, 2019) or effects on emission of volatile signals such as herbivore‐induced plant volatiles used for host location (see Stenberg, Heil, Åhman, & Björkman, 2015).…”

Striking clone-specific nymph deformity in pea aphid exposed to heat stress

“…Acyrthosiphon pisum, an important crop pest [16] and eco-evo model organism [17], shows impressive phenotypic plasticity, a phenomenon of producing variable phenotypes in response to environmental stress [18,19]. Reproductive, ontogenetic, and phenotypic plasticities are contextual and may differ across polymorphic lineages, including green and pink morphs, underlined by metabolic differences [21][22][23][24][25]. The optimal temperatures for A. pisum range from 20°C to 25°C, with upper limits up to 30°C, depending on the geographic location and adaptability of aphid lineages [13].…”