Harvestmen

Chemical

Harvestmen are well known for being chemically protected. They exude strongly odored secretions from their scent glands, called ozopores, that act as a shield against predators; this creates a strong and unpleasant taste, which is often their most effective defense. In Cyphophthalmi the scent glands release naphthoquinones, chloro-naphthoquinones and aliphatic methyl ketones, Insidiatores use nitrogen-containing substances, terpenes, aliphaticketones, and phenolics, while Grassatores use alkylated phenolics and benzoquinones, and Palpatores use substances like naphthoquinones, methyl- and ethyl-ketones. These secretions have successfully protected the harvestmen against wandering spiders (Ctenidae), wolf spiders (Lycosidae) and Formica exsectoides ants. However, these chemical irritants are not able to prevent four species of harvestmen being preyed upon by the black scorpion Bothriurus bonariensis (Bothriuridae). These secretions contain multiple volatile compounds that vary among individuals and clades.