Interactions among three species of cereal aphids simultaneously infesting wheat

Area of Science:

• Agricultural Entomology
• Plant-Insect Interactions
• Pest Management

Background:

• Wheat is a vital global crop susceptible to aphid infestations.
• Multiple aphid species can co-occur on wheat, potentially influencing each other.
• Understanding interspecific aphid competition is crucial for effective pest control strategies.

Purpose of the Study:

• To investigate the survival, development, and fecundity of three aphid species when interacting on wheat.
• To determine if conspecific or heterospecific interactions affect aphid performance and behavior.
• To identify potential amensalistic relationships and their impact on aphid populations.

Main Methods:

• Wheat plants (Triticum aestivum L., cv. TAM 107) were infested with pairs of greenbug (Schizaphis graminum), Russian wheat aphid (Diuraphis noxia), or bird cherry-oat aphid (Rhopalosiphum padi).
• Nymphs of first or fourth instars were used to assess survival, developmental time, fecundity, movement, and tissue affinity.
• Comparisons were made between conspecific and heterospecific pairings, and between feeding on same vs. different plant tissues.

Main Results:

• Overall survival from first instar to reproduction was high (90-100%).
• Diuraphis noxia exhibited faster development with conspecifics and on the same plant tissue.
• Amensalism was observed: D. noxia development was delayed with S. graminum, and fecundity reduced with S. graminum and R. padi. S. graminum survival was reduced with R. padi.

Conclusions:

• Interspecific aphid interactions on wheat can significantly impact development, fecundity, and survival, with evidence of amensalism.
• Aphid-induced changes in plant physiology appear to mediate these interactions, particularly for early instars.
• Understanding these complex dynamics is essential for predicting aphid population dynamics and developing integrated pest management strategies.