Evolutionary assembly of cooperating cell types in an animal chemical defense system.

How the functions of multicellular organs emerge from the underlying evolution of cell types is poorly understood. We deconstructed evolution of an organ novelty: a rove beetle gland that secretes a defensive cocktail. We show how gland function arose via assembly of two cell types that manufacture distinct compounds. One cell type, comprising a chemical reservoir within the abdomen, produces alkane and ester compounds. We demonstrate that this cell type is a hybrid of cuticle cells and ancient pheromone and adipocyte-like cells, executing its function via a mosaic of enzymes from each parental cell type. The second cell type synthesizes benzoquinones using a chimera of conserved cellular energy and cuticle formation pathways. We show that evolution of each cell type was shaped by coevolution between the two cell types, yielding a potent secretion that confers adaptive value. Our findings illustrate how cooperation between cell types arises, generating new, organ-level behaviors.

Mechanical evaluation of 3D printed biomimetic non-Euclidean saddle geometries mimicking the mantis shrimp.

Engineering design has drawn inspiration from naturally occurring structures to advance manufacturing processes and products, termed biomimetics. For example, the mantis shrimp, orderStomatopoda, is capable of producing one of the fastest appendage strikes in the world with marginal musculoskeletal displacement. The extreme speed of the mantis shrimp's raptorial appendage is due to the non-Euclidean hyperbolic paraboloid (i.e. saddle) shape within the dorsal region of the merus, which allows substantial energy storage through compression in the sagittal plane. Here, investigation of 3D printed synthetic geometries inspired by the mantis shrimp saddle geometry has revealed insights for elastic energy storage (i.e. spring-like) applications. Saddles composed of either astiffor aflexibleresin were investigated for spring response to explore the geometric effects. By modulating the saddle geometry and testing the spring response, it was found that, for thestiffresin, the spring constant was improved as the curvature of the contact and orthogonal faces were maximized and minimized, respectively. For theflexibleresin, it was found that the spring constant increased by less than 250 N mm-1as the saddle geometry changed, substantiating that the flexible component of mantis saddles does not contribute to energy storage capabilities. The geometries of two saddles from the mantis shrimp speciesO. scyllaruswere estimated and exhibited similar trends to manufactured saddles, suggesting that modulating saddle geometry can be used for tailored energy storage moduli in spatially constrained engineering applications.