Adaptive trade-offs between vertebrate defence and insect predation drive Amazonian ant venom evolution.

Stinging ants have diversified into various ecological niches, and selective pressures may have contributed to shape the composition of their venom. To explore the drivers underlying venom variation in ants, we sampled 15 South American rainforest species and recorded a range of traits, including ecology, morphology and venom bioactivities. Principal component analysis of both morphological and venom bioactivity traits reveals that stinging ants display two functional strategies where species have evolved towards either an exclusively offensive venom or a multi-functional venom.

Exaptation of an evolutionary constraint enables behavioural control over the composition of secreted venom in a giant centipede.

Venoms are biochemical arsenals that have emerged in numerous animal lineages, where they have co-evolved with morphological and behavioural traits for venom production and delivery. In centipedes, venom evolution is thought to be constrained by the morphological complexity of their venom glands due to physiological limitations on the number of toxins produced by their secretory cells. Here we show that the uneven toxin expression that results from these limitations have enabled Scolopendra morsitans to regulate the composition of their secreted venom despite the lack of gross morphologically complex venom glands.

Venom exaptation and adaptation during the trophic switch to blood-feeding by kissing bugs.

Kissing bugs are known to produce anticoagulant venom that facilitates blood-feeding. However, it is unknown how this saliva evolved and if the venom produced by the entomophagous ancestors of kissing bugs would have helped or hindered the trophic shift. In this study, we show that venoms produced by extant predatory assassin bugs have strong anticoagulant properties mediated chiefly by proteolytic degradation of fibrinogen, and additionally contain anticoagulant disulfide-rich peptides.

Subsidence after Trapeziometacarpal Arthroplasty.

Purpose: Surgeons sometimes ascribe inadequate comfort and capability after trapeziometacarpal (TMC) arthroplasty to movement of the trapezium toward the scaphoid (subsidence or reduced trapezial space height [TSH]). We asked the following: (1) What percentage of studies found a relationship between subsidence of the metacarpal toward the distal scaphoid and measures of grip strength, capability, pinch strength, pain intensity, or patient satisfaction after TMC arthroplasty and what study characteristics are associated with having notable correlation? (2) What study factors are associated with greater postoperative TSH? (3) What is the mean subsidence over time?

Methods: We conducted a systematic review by querying PubMed, Cochrane, and Web of Science databases from 1986 and onward. Using inclusion criteria of TMC arthroplasty inclusive of trapeziectomy, ligament reconstruction and tendon interposition, tendon interposition, and prosthetic arthroplasty and a measure of subsidence, 91 studies were identified.