Nutrient regulation in the pea aphid Acyrthosiphon pisum: application of a novel geometric framework to sugar and amino acid consumption

Abstract

A recently developed framework was applied to investigate the responses of newborn pea aphids, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), to simultaneous variations in dietary suerose and amino acid levels. The location of functional 'targets' for intake and growth were determined experimentally using performance criteria. Behavioural rules employed by insects to approach these targets were investigated by reference to the geometry of arrays of intake and growth across a range of diets. First-instar aphids were fed one of thirty-one chemically-defined diets ranging in sucrose concentration from 200 to 1000 mM and amino acid concentration from 25 to 250 mM. Insect survivorship, dry weight, protein-and carbohydrate-derived growth were high for all diets except those with the lowest nutrient levels. Peaks in final dry weight and protein content identified the intake target as the point reached by larvae fed the 600mM sucrose, 7 5 m~ amino acid diet. Aphids regulated sucrose primarily by consumption (i.e. behaviourally), whereas amino acids were regulated post-ingestively (i.e. by physiological mechanisms).

The importance of protein type and protein to carbohydrate ratio for survival and ovarian activation of caged honeybees (Apis mellifera scutellata)

“…In other insects the ideal ratio is more biased towards carbohydrates. First instar pea aphids perform best on a diet with an amino acid:sucrose ratio of 1:19 mg/mg (Abisgold et al, 1994), showing a strong bias towards carbohydrate, and confirming the prediction of Simpson and Raubenheimer (1993) that insects with mycetocyte symbionts would have lower P:C ratios than those without. In a recent study of ants (Rhytidoponera metallica), the optimal P:C ratio for colony performance was 1:2, measured in terms of both worker mortality and the number of larvae raised (Dussutour and Simpson, 2008).…”

Effects of total dietary nitrogen and nitrogen form on the development of xylophagous leafhoppers

“…Inverse correlations between CR and nitrogen concentrations are consistent with compensatory feeding based on nitrogen concentrations, which has been extensively documented for other herbivorous insects (Slansky and Feeny, 1977;Slansky and Wheeler, 1994). However, inverse correlations between CR and low dietary carbon are also consistent with evidence that aphids adjust carbon accumulation to ideal target rates (Raubenheimer and Simpson, 1993) by varying CR; target rates of nitrogen retention were achieved post-ingestively by variable rates of nitrogen excretion (Absigold et al, 1994).…”

Convergence of carbohydrate-biased intake targets in caged worker honeybees fed different protein sources

“…The strong bias shown by these broodless caged workers towards dietary carbohydrate is confirmed by the similar intake targets on the three very different protein sources. Strong carbohydrate bias is also evident in the intake target of first-instar pea aphids, which perform best on a diet with an amino acid to sucrose ratio of 1:19mgmg -1 (Abisgold et al, 1994), and other insects with endosymbiotic bacteria that contribute to nitrogen metabolism (Raubenheimer and Simpson, 1997;Simpson and Raubenheimer, 1993). Recently it has been shown in both flies and grasshoppers that a strongly carbohydrate-biased diet maximises lifespan but not reproduction (Fanson et al, 2009;Lee et al, 2008;Maklakov et al, 2008).…”