The praying mantis (Mantodea) as predator of the poisonous red-spotted newt Notophthalmus viridescens (Amphibia: Urodela: Salamandridae)

Abstract

A Chinese praying mantis, Tenodera sinensis, was observed feeding on a living red-spotted newt, Notophthalmus viridescens. Specimens of that newt's population are known to contain high concentrations of tetrodotoxin (TTX), a specific blocker of voltage-gated sodium channels. After experimental oral administration of a TTX-solution (1 mg/ ml) to adult specimens of four mantis species, all survived high TTX concentrations (up to 30.8 lg/g body mass) as revealed by analysis of their body extracts, but they are rapidly killed by intra-abdominal injection of 1 lg TTX. The toxin was found to be gradually excreted with faeces. As demonstrated by monoclonal antibody-based immunohistochemical technique, TTX does not penetrate the mid-gut membrane, since it was localized only in the gut lumen, but not in the epithelial cells. This prevents the toxin to reach its target, the sodium channels of the insect's nervous system, and enables the mantids to feed on toxic prey without risking poisoning.

Noxious newts and their natural enemies: Experimental effects of tetrodotoxin exposure on trematode parasites and aquatic macroinvertebrates

“…Correspondingly, several macroinvertebrate taxa have been shown to consume larval or embryonic Taricha without notably ill effects, including larvae of Trichoptera, Zygoptera, and Anisoptera (Gall et al, 2012, 2011; Toledo et al, 2016). For instance, caddisfly larvae consume the eggs of T. granulosa (maximum of 1.53 µg TTX/egg) (Gall et al, 2012; Mebs et al, 2016) while dragonfly nymphs will eat larvae of both T. granulosa and T. torosa (0.296 ± 0.103 µg TTX/larva) (Bucciarelli and Kats, 2015; Mebs et al, 2016). Further consistent with our results, mayfly larvae – which are not predators of newt larvae – are often cited as bioindicator taxa sensitive to adverse environmental conditions, including hypoxia and contaminants (Gerhardt, 1996; Hodkinson and Jackson, 2005; Menetrey et al, 2008; O’Halloran et al, 2008).…”

Molecular physiology of chemical defenses in a poison frog

“…Voltage gated-sodium channels are a well-known target of frog alkaloids (Santos et al, 2016), but to our knowledge the epithelial sodium channel has not been tested with poison frog alkaloids, making it unclear whether this channel binds alkaloids. Alternatively, these channels could play a role in retaining alkaloids in the gut epithelium similar to resistance of tetrodotoxin in mantids (Mebs et al, 2016). Another transporter of note is the Na + /K + -ATPase pump, the beta 2 subunit expression of which was elevated in chemically defended wild-caught frogs compared with laboratory frogs.…”

Beetle bombing always deters praying mantises

“…For example, mantises such as T. sinensis could consume toxic caterpillars after removing ('gutting') the midgut containing toxic plant material (Rafter, Agrawal & Preisser, 2013;Mebs et al, 2017;Mebs, Wunder & Toennes, 2019). Several mantis species could also tolerate noxious chemicals such as tetrodotoxin, cardenolides, and quinine used as anti-predator defences by toxic arthropods (Mebs, Yotsu-Yamashita & Arakawa, 2016;Mebs et al, 2017;Rafter et al, 2017aRafter et al, , 2017bMebs, Wunder & Toennes, 2019). Therefore, bombing plays an essential role in defending against mantis predation, although additional experiments are needed to test the importance of heat in the successful defence of P. jessoensis against mantises.…”