Chemical Tools of Octopus maya during Crab Predation Are Also Active on Conspecifics

Abstract

Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus), the crown conch snail (Melongena corona bispinosa), as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3kDa leading to a metabolic phase (>3kDa) and a neurotoxic fraction (<3kDa). The neurotoxic fraction injected in the crabs caused paralysis and postural changes. Crabs recovered to their initial condition within two hours, which suggests that the effects of the neurotoxic fraction were reversible. The neurotoxic fraction was also active on O. maya conspecifics, partly paralyzing and sedating them; this suggests that octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey.

Digestive Physiology of Octopus maya and O. mimus: Temporality of Digestion and Assimilation Processes

“…Enzymes from salivary glands in O. maya participating in the first chyme pulses are found 20 min after the meal (Pech-Puch et al, 2016). In O. mimus this process occurs 140 min after the meal (Linares et al, 2015), indicating again that habitat temperature of each species modulates this process (Figure 2B).…”

“…In O. maya adults, 20 min is enough to ingest a crab of around 100 g at 26°C (Martínez et al, 2011 ; Figure 2A ). During this time, O. maya injects saliva to the prey which contains chymotrypsin and a neurotoxic fraction that causes paralysis and postural changes in the crab (Pech-Puch et al, 2016 ). After, the first pulse of chyme containing soluble nutrients is absorbed, initiating the digestive process.…”

Marine Natural Products from the Yucatan Peninsula

“…Finally, these compounds showed no antipredatory (deterrent) activity against the Serranus cabrilla fish, which were collected in the Mediterranean Sea, or significant antialgal activity against the diatom Nitzchia acicularis ( Figure 7). Pech-Puch et al reported the isolation of another indole, serotonin (44), from the salivary glands of Octopus maya collected in Sisal, Yucatan state in 2016 [23]. The neurotoxic activity previously found in its extract was attributed to that compound (Figure 7).…”

“…No biological data were reported for 45-48. Pech-Puch et al reported the isolation of another indole, serotonin (44), from the salivary glands of Octopus maya collected in Sisal, Yucatan state in 2016 [23]. The neurotoxic activity previously found in its extract was attributed to that compound (Figure 7).…”

Cephalopods as Predators: A Short Journey among Behavioral Flexibilities, Adaptions, and Feeding Habits

“…Venom is used by cuttlefishes and octopods to kill the prey and for muscle relaxation. Octopuses bored holes in the carapace, the eye or the arthrodial membrane of crustaceans (Grisley et al, 1996 ; Pech-Puch et al, 2016 ). The selection of the preferred area to inject the cephalotoxin in the crab seems to be a combination of factors related to prey and octopus size.…”