The hypothesis that phenotypic plasticity is maintained by divergent natural selection acting across different environments predicts that populations and species exposed to highly variable environments will express high levels of plasticity. I tested this prediction by measuring the behavioral and morphological responses to aeshnid dragonfly larvae of 16 tadpole species and asking whether preda...

Among the violently poisonous species of Amanita, none has received more attention than A. phalloides (Fr.) Secr. By 1959, five related cyclopeptidic toxins had been extracted from this mushroom and named phalloidin, phalloin, and a-, j3-, and y-amanitin. T. Wieland and 0. Wieland (Pharmacol. Rev. 11:87, 1959) reviewed the chemistry and toxicology of these compounds. A sixth toxin, phallacidin,...

Habitat heterogeneity has been shown to promote co-existence of closely related species. Based on this concept, a field study was conducted on the niche partitioning of three territorial congeneric species of skimmers (Anisoptera: Libellulidae) in Northeast Algeria during the breeding season of 2011. According to their size, there is a descending hierarchy between Orthetrum nitidinerve Sélys, O...

We are constantly surprised by the ability of relatively simple animals to perform precise visually guided movements within complex visual scenes, often using eyes with limited resolution. Exceptional examples include the capture of airborne prey by dragonflies, the learning flights of bees and wasps, and the tracking of conspecifics by crabs on intertidal mudflats. Most studies have focused on...

In a recent article in PNAS, Clapham and Karr (1) related the maximum wing length (MWL) of different Odonatoptera and Orthoptera species to Phanerozoic atmospheric oxygen partial pressure (pO2) as predicted by the GEOCARBSULF model (2). They argued that the MWL data assigned to 10-Myr periods is well correlated with elevated Paleozoic pO2 levels, but that the correlation weakens and is ultimate...

Intercepting a moving object requires prediction of its future location. This complex task has been solved by dragonflies, who intercept their prey in midair with a 95% success rate. In this study, we show that a group of 16 neurons, called target-selective descending neurons (TSDNs), code a population vector that reflects the direction of the target with high accuracy and reliability across 36...

While predators such as dragonflies are dependent on visual detection of moving prey, social interactions make conspecific detection equally important for many non-predatory insects. Specialized 'acute zones' associated with target detection have evolved in several insect groups and are a prominent male-specific feature in many dipteran flies. The physiology of target selective neurons associat...

Dragonflies are colorful and large-eyed animals strongly dependent on color vision. Here we report an extraordinary large number of opsin genes in dragonflies and their characteristic spatiotemporal expression patterns. Exhaustive transcriptomic and genomic surveys of three dragonflies of the family Libellulidae consistently identified 20 opsin genes, consisting of 4 nonvisual opsin genes and 1...