Venom of prey‐specialized spiders is more toxic to their preferred prey: A result of prey‐specific toxins

Abstract

In specialized predators, a variety of adaptations have evolved to such a level of specificity that they allow very effective exploitation of focal prey. Venom is an essential adaptive trait of predatory venomous species, such as spiders, yet our knowledge of spider venom is incomplete. In agreement with the prey preference hypothesis, we expected that the venom of spider specialists should be more toxic to focal than to alternative prey, because it is composed of prey-specific toxins. Here we used spiders with three types of trophic specializations: specialists that were ant-eating, termite-eating and spider-eating. We compared the efficacy of prey capture of preferred and alternative prey (measured as paralysis latency) with that of related generalists and profiled the venom of the studied species using proteomic methods. We used 22 spider species: six myrmecophagous, two termitophagous, three araneophagous and 11 euryphagous generalist species belonging to different families. We found that ten of the eleven specialist species induced significantly shorter paralysis latency in preferred prey than in alternative prey. Generalists exhibited either similar efficiency on both prey types or slightly higher efficiency on preferred prey. Multivariate analysis of proteomic profiles (peptides and proteins) revealed significant differences between trophic specializations, particularly in peptides. Specialists appear to have venom composed of unique specific compounds as revealed by the multivariate ordination and indicator analysis. These components are likely prey-specific toxins.

Diet Breadth Mediates the Prey Specificity of Venom Potency in Snakes

“…While venom has evolved in response to several factors [10][11][12], for species that use venom for predation, various functional aspects of their venoms, such as their potency, are expected to reflect the evolutionary pressures related to capturing prey [5]. In particular, as the functional ability of such venoms are selected through their efficacy against the organisms they are most frequently targeted towards, they are expected to show patterns of prey-specific potencies [13,14]. Examples of venoms which show such prey-specific potency are found across the animal kingdom, including spiders [13,[15][16][17], cone snails [11,18,19], centipedes [20], heteropterans [21] and snakes [22].…”

“…In particular, as the functional ability of such venoms are selected through their efficacy against the organisms they are most frequently targeted towards, they are expected to show patterns of prey-specific potencies [13,14]. Examples of venoms which show such prey-specific potency are found across the animal kingdom, including spiders [13,[15][16][17], cone snails [11,18,19], centipedes [20], heteropterans [21] and snakes [22]. Furthermore, in snakes, prey-specific potencies seem to be the rule rather than the exception, with increasing potencies found to be associated with venoms tested on animals more closely related to the snakes' diet [14,23,24].…”

“…In the simplest case, the venom from a predator which preys on a single species will be prey-specifically selected against that given species [13]. However, predators typically have diets comprising multiple species, often from a range of taxonomic groups.…”

No ontogenetic shift in the realised trophic niche but in Batesian mimicry in an ant-eating spider

“…the ability to process a selected food type, has not been studied yet in this species, although venomic adaptation has. Mexcala has very potent venom that is more efficient on ants than on termites when compared to a closely related salticid species 32 . Its venom likely possesses specific toxins effective especially on ants 33 .…”

Alteration of Bumblebee Venom Composition toward Higher Elevation

“…Additionally, venom toxin levels may correlate with predator distributions and physiology due to the coevolutionary theory which suggests a phenotype matching occurring in predator-prey interactions. This is known as the escalating arms race and is well documented in predatory venoms [15,41,[54][55][56]. As the frequency and the strength of biotic encounters decrease at high elevations due to colder climatic conditions [43,44,[57][58][59][60], a lower predator pressure is expected to be exerted on bumblebees at high elevations.…”