Is there ontogenetic shift in the capture traits of a prey-specialized ant-eating spider?

The onset of piscivory in a freshwater fish species: analysis of behavioural and physiological traits

The onset of piscivory in fish, resulting in a shift from zooplankton or invertebrate to fish prey, was studied on pikeperch (Sander lucioperca) larvae displaying and not displaying piscivorous behaviour at different ages (23, 30, 37, 44 and 52 days post-hatching) using behavioural (attack, capture and swimming activity), morphological (allometry) and digestive enzymatic (trypsin, α-amylase and pepsin) analyses. The shift from zooplanktonic food items (Artemia nauplii) to a piscivorous diet did not occur at the same time for all individuals within the same cohort. Predation tests, conducted under controlled conditions (20°C; ad libitum feeding), showed that some larvae attacked fish prey as early as the age of 3 weeks [11.0 ± 1.3 mm total length (TL)], whereas others did not start until the age of 6 weeks (16.6 ± 1.9 mm TL). Piscivorous individuals were bigger, with larger heads, longer tails, higher acid protease and lower alkaline protease activities, than non-piscivorous conspecifics. In conclusion, high interindividual variability in morphological and digestive system developments linked to the development of predatory abilities could induce cannibalism in fish.

MALDI-TOF Mass Spectrometric Profiling of Spider Venoms

Fingerprinting by means of matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) represents a tool for rapidly detecting proteinaceous compounds from spider venoms. Here we describe an optimized protocol and discuss methodological details with the aim of providing a platform for obtaining the most informative and reproducible mass spectral data.

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

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.

A new ant-eating spider genus Suffascar (Araneae:Zodariidae) endemic to Madagascar: a considerable extension of the dual femoral organ clade

The new zodariid genus Suffascar, gen. nov. is described from Madagascar. It is apparently endemic to the island, common and speciose. Twelve new species were discovered and are here described: Suffascar albolineatus, sp. nov., S. fianara, sp. nov., S. fisheri, sp. nov., S. fitzpatrickae, sp. nov., S. gigas, sp. nov., S. griswoldi, sp. nov., S. macromma, sp. nov., S. micromma, sp. nov., S. nonus, sp. nov., S. scutatus, sp. nov., S. sufficiens, sp. nov. and S. tofti, sp. nov. It is well known that Zodariidae with femoral organs are specialised consumers of ants or termites, although the exact role of these glands still remains obscure. Suffascar is part of the ‘dual femoral organ clade’ (DF), which also includes Asceua Thorell, 1887, Suffasia Jocqué, 1991, and Suffrica Henrard & Jocqué, 2015. Using a morphology-based phylogenetic analysis, we test whether zodariids sharing the dual femoral organ are part of the same group as the ‘single femoral organ clade’ (SF) or form a separate monophyletic group. It appears that SF and DF constitute clearly monophyletic entities with a sister-group relation. These groups may be considered as distinct subfamilies and, together, they may turn out to be sister to the Storeninae (which then could be re-established). An analysis that focuses on these questions is underway. http://zoobank.org/urn:lsid:zoobank.org:pub:281E1357-FAEE-4300-B1BB-F0D43E724E91