Populus-nigra
Guides
Pemphigus spyrothecae
Poplar Spiral Gall Aphid
Pemphigus spyrothecae is a gall-forming aphid that induces distinctive spiral-shaped galls on leaf petioles of Populus nigra. The species exhibits eusocial behavior with a sterile soldier caste comprising first-instar nymphs with thickened hind legs that defend the colony against predators. Colony defense includes fortress defense, gall repair, and maintenance of colony hygiene. The aphid has a holocyclic life cycle with four generations: fundatrix, apterous virginoparae, alate sexuparae, and sexual males and females. Genetic relatedness within galls is high due to clonal reproduction, with clonal mixing averaging 0.68-10.4% across populations.