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Pink muhly grass Muhlenbergia capillaris (Lamark) Trinius is a perennial, tussock-forming grass that is native to North and Central America. The reddish-purple coloration of the spikes of this species has resulted in this grass becoming popular as an ornamental plant around the world. Interestingly, very few insects have been reported to be associated with this grass. I therefore examined arthropod assemblages on M. capillaris in two urban parks in central Japan in autumn and found that the aphid Hysteroneura setariae (Thomas, 1878) (Hemiptera: Aphididae) and its natural ladybird predator Coccinella septempunctata L., 1758 (Coleoptera: Coccinellidae) occurred at high densities at one of the parks (ca. 9000 vs 3.4 individuals/m2). Other insect pests, such as the moth Helicoverpa armigera (Hübner, 1808) (Lepidoptera: Noctuidae) and mirid bugs were also present, but at markedly lower densities. Since H. setariae is not a pest in Japan and C. septempunctata is a beneficial predator, M. capillaris could be used as a banker plant in agricultural fields as well as in urban green spaces.

Pineapple lilies Eucomis autumnalis (Mill.) Chitt. and Eucomis comosa Houtt. ex. Wehrh. are endemic herbaceous plants in southern Africa but are planted as ornamental bulbous plants globally. The flowers are known to be primarily pollinated by pompilid wasps in their native range. In a Japanese botanical garden, Blattella nipponica Asahina, 1963 cockroaches visited the inflorescences of the two Eucomis species, fed on the floral nectar, and used the comae (i.e., leaf-like tufts on the top of inflorescences) as physical shelters and transported the pollen, thereby resulting in a fruit set. Ants, flies, and beetles were also observed to visit the flowers but did not touch the anthers or stigmas. These observations suggest that ground-dwelling cockroaches can act as pollinators of Eucomis flowers in an ex-situ setting.