How symbiotic bacteria influence plant utilisation by the polyphagous aphid, Aphis fabae

Area of Science:

• Insect-microbe interactions
• Symbiotic relationships in insects
• Aphid biology and ecology

Background:

• Buchnera are essential symbiotic bacteria for aphids, providing nutrients.
• Aphid performance is influenced by host plant quality and symbiotic bacteria.
• Understanding the interplay between aphids, Buchnera, and host plants is crucial for pest management.

Purpose of the Study:

• To investigate how different host plant species affect the contribution of Buchnera to aphid performance.
• To determine if the plant species influences the importance of the Buchnera symbiosis for aphid growth.

Main Methods:

• Larvae of Aphis fabae, both with (symbiotic) and without (aposymbiotic) Buchnera, were reared on 16 different plant species.
• Aphid mortality and relative growth rate (RGR) were measured on each plant species.

Main Results:

• Aphid mortality was low across most plant species.
• Relative growth rate (RGR) varied significantly with plant species for both symbiotic and aposymbiotic aphids.
• The absence of Buchnera generally reduced aphid RGR, and this reduction varied depending on the host plant.
• Symbiotic aphids exhibited higher RGR (0–0.29 μg μg-1 day-1) compared to aposymbiotic aphids (0–0.17 μg μg-1 day-1).

Conclusions:

• The aphid host plant species significantly influences the contribution of Buchnera to aphid performance.
• The symbiosis with Buchnera may be especially critical for aphids feeding on plants with poor-quality phloem sap, characterized by high amino acid content but low essential amino acid concentrations.