Ground pearls are the large, sedentary adult forms of root-sap feeding insects. Here, two Eurhizococcus brasiliensis hang suspended from grape roots deep underground while a Linepithema micans ant gathers the honeydew exuded by the pearls. These insects are significant pests in Brazilian vineyards. Bento Gonçalves, Rio Grande do Sul, Brazil

Ants and scale insects are often tight ecological associates, even under the soil. Here, a first instar ground pearl (Eurhizococcus brasiliensis) is carried by a Linepithema micans worker. The ground pearls produce honeydew that feeds the ants, while the ants protect the pearls and carry their young to new host plants. Bento Gonçalves, Rio Grande do Sul, Brazil

Linepithema micans astride a ground pearl. The "pearl" is actually a honeydew-producing scale insect that feeds on the sap of roots. Bento Gonçalves, Rio Grande do Sul, Brazil