Cantharidin world in nature: a concealed arthropod assemblage with interactions via the terpenoid cantharidin

Abstract

Cantharidin is produced by beetles of only two families, the Meloidae and the Oedemeridae. This substance is a defensive terpenoid that is toxic to the enemies of the beetles. Cantharidin also attracts other groups of insects and has been used as a bait to trap them. Cantharidin-baited traps deployed in central Japan captured coleopterans (Anthicidae, Endomychidae, Pyrochroidae, and Scarabaeidae), dipterans (Ceratopogonidae), hymenopterans (Formicidae), and harvestmen (Podoctidae). The seasonal occurrences of these arthropods, their sex ratios, known feeding choices, and mating habits suggest three possible underlying reasons for the attractancy of cantharidin: (i) it is accumulated as a defense against enemies and sometimes for transfer from males to females as a nuptial gift; (ii) it is used as a chemical cue in food searching; and (iii) it is used as an aggregation pheromone by mature arthropod individuals. The group of canthariphilous arthropods we describe represents a cryptic ecological assemblage with rare chemical networking among apparently unrelated species.

Cantharidin world on islands: Species diversity of canthariphilous arthropods in the Izu–Ogasawara Arc

“…This is the first report of a canthariphilous community on the Pacific islands, although Hashimoto and Hayashi (2014) reported such a community on the central part of the Japanese mainland. Cantharidin baits attracted three orders of insects, Coleoptera (Anthicidae and Pyrochroidae), Diptera (Ceratopogonidae) and Hymenoptera (Formicidae), and one harvestman (Podoctidae).…”

“…Cantharidin is used not only in food searching but also in defense and aggregation (Hashimoto & Hayashi ). In our study, the two species of beetles, Clavicollis fugiens (Anthicidae) and Pseudopyrochroa laticollis (Pyrochroidae), were attracted to the cantharidin traps, but most of them were males.…”

“…Inter-and intraspecific communication in terrestrial arthropod communities highly depends on mediation by semiochemicals such as pheromones, allomones, kairomones, attractants and repellents (Blum 1996). Cantharidin world with a chemical networks of arthropods mediated by cantharidin is one of such arthropod communities (Hashimoto & Hayashi 2014). Cantharidin (C 10 H 12 O 4 ) is the defense chemical synthesized and secreted by beetles of only two families, Meloidae and Oedemeridae, as far as currently known (Carrel & Eisner 1974;Carrel et al 1986).…”

“…They are so-called as "canthariphilous" arthropods including insects of one opiliones, seven coleopteran, six dipteran, three hemipteran and three hymenopteran families (Hemp & Dettner 2001;Hashimoto & Hayashi 2014). Hashimoto and Hayashi (2014) suggested three possible pathways for attraction of these arthropods to cantharidin, as cantharidin (i) is stored as a defense against predatory animals and as nuptial gift from males to females at mating (e.g. Eisner et al 1996a, b;Dettner 1997); (ii) functions as a chemical cue for food and host searching (e.g.…”

Cantharidin world in air: Spatiotemporal distributions of flying canthariphilous insects in the forest interior

“…). However, cantharidin also functions by attracting other groups of arthropods and forming a peculiar community, the so‐called “cantharidin world,” in which the members interact inter‐ and intra‐specifically using this chemical (reviewed by Hashimoto & Hayashi ). This world consists of four possible functional groups: (i) producers of cantharidin (beetles of Meloidae and Oedemeridae); (ii) consumers of cantharidin to use for their own defense against carnivorous enemies, or to transfer from males to the mated female as a nuptial gift to be used for her own and egg protection (e.g.…”