Defensive nymphs in the water-repellent gall of the social aphid Colophina monstrifica (Hemiptera: Aphididae: Eriosomatinae)

The aphid Colophina monstrifica forms woolly colonies with sterile soldiers on the secondary host Clematis uncinata in Taiwan. However, the gall or primary-host generation of C. monstrifica has not been found to date. We successfully induced galls of the species on trees of Zelkova serrata through attaching its eggs onto the trees, and also found a few naturally formed galls on another Z. serrata tree. The identity of the aphids was confirmed by examining their morphology and mitochondrial DNA sequences. First- and second-instar nymphs in the galls exhibited attacking behavior toward artificially introduced moth larvae. Observations with a scanning electron microscope revealed that the gall inner surface was densely covered with minute trichomes. This indicates the water repellency of the inner surface, and strongly suggests that young nymphs of C. monstrifica dispose of honeydew globules outside the gall, as known in the congener C. clematis.

A Review of the Biology of Cerataphidini (Hemiptera, Aphididae, Hormaphidinae), Focusing Mainly on Their Life Cycles, Gall Formation, and Soldiers

Species of the aphid tribe Cerataphidini (Hormaphidinae) form galls of various shapes onStyraxtrees, their primary host, throughout East and Southeast Asia including tropical rainforests. All known species of the tribe produce second-instar sterile soldiers on the primary host and some also produce first-instar sterile soldiers on the secondary host. Here, we review their complicated life cycles with or without host alternation, the formation process of their remarkable galls (flower-like multiple-cavity galls in particular), and all morphs including soldiers. The life cycles of cerataphidines are basically the same as those of the subfamily Eriosomatinae, but in tropical and subtropical regions their life cycles are not very rigidly tuned to seasonal changes in the climate if any. In addition, cerataphidine galls in these regions last at least several months, or at times even for over one year; thus it often takes longer than one year to complete their life cycles.