text: There are a number of AFPs found in insects, including those from Dendroides, Tenebrio and Rhagium beetles, spruce budworm and pale beauty moths, and midges (same order as flies). Insect AFPs share certain similarities, with most having higher activity (i.e. greater thermal hysteresis value, termed hyperactive) and a repetitive structure with a flat ice-binding surface. Those from the closely related Tenebrio and Dendroides beetles are homologous and each 12–13 amino-acid repeat is stabilized by an internal disulfide bond. Isoforms have between 6 and 10 of these repeats that form a coil, or beta-solenoid. One side of the solenoid has a flat ice-binding surface that consists of a double row of threonine residues. Other beetles (genus Rhagium) have longer repeats without internal disulfide bonds that form a compressed beta-solenoid (beta sandwich) with four rows of threonine residus, and this AFP is structurally similar to that modelled for the non-homologous AFP from the pale beauty moth. In contrast, the AFP from the spruce budworm moth is a solenoid that superficially resembles the Tenebrio protein, with a similar ice-binding surface, but it has a triangular cross-section, with longer repeats that lack the internal disulfide bonds. The AFP from midges is structurally similar to those from Tenebrio and Dendroides, but the disulfide-braced beta-solenoid is formed from shorter 10 amino-acids repeats, and instead of threonine, the ice-binding surface consists of a single row of tyrosine residues. Springtails (Collembola) are not insects, but like insects, they are arthropods with six legs. A species found in Canada, which is often called a "snow flea", produces hyperactive AFPs. Although they are also repetitive and have a flat ice-binding surface, the similarity ends there.  Around 50% of the residues are glycine (Gly), with repeats of Gly-Gly- X or Gly-X-X, where X is any amino acid. Each 3-amino-acid repeat forms one turn of a polyproline type II helix. The helices then fold together, to form a bundle that is two helices thick, with an ice-binding face dominated by small hydrophobic residues like alanine, rather than threonine.  Other insects, such as an Alaskan beetle, produce hyperactive antifreezes that are even less similar, as they are polymers of sugars (xylomannan) rather than polymers of amino acids (proteins).  Taken together, this suggests that most of the AFPs and antifreezes arose after the lineages that gave rise to these various insects diverged. The similarities they do share are the result of convergent evolution.