Mohammadreza Khalesi

Conserved class of queen pheromones stops social insect workers from reproducing

Long Live the Queen Eusociality is often considered to have arisen, at least in part, due to the inclusive fitness that workers gain through helping their queen sister to raise her offspring. Van Oystaeyen et al. (p. 287; see the Perspective by Chapuisat) characterized the sterility-inducing queen pheromone across three distantly related eusocial hymenopterans (a wasp, a bumblebee, and a desert ant) and synthesized data across 69 other species. Queen pheromones appear to be remarkably conserved, which suggests that reproductive manipulation has ancient roots. Social insect queens use an ancient, evolutionarily conserved class of pheromones to prevent worker reproduction. [Also see Perspective by Chapuisat] A major evolutionary transition to eusociality with reproductive division of labor between queens and workers has arisen independently at least 10 times in the ants, bees, and wasps. Pheromones produced by queens are thought to play a key role in regulating this complex social system, but their evolutionary history remains unknown. Here, we identify the first sterility-inducing queen pheromones in a wasp, bumblebee, and desert ant and synthesize existing data on compounds that characterize female fecundity in 64 species of social insects. Our results show that queen pheromones are strikingly conserved across at least three independent origins of eusociality, with wasps, ants, and some bees all appearing to use nonvolatile, saturated hydrocarbons to advertise fecundity and/or suppress worker reproduction. These results suggest that queen pheromones evolved from conserved signals of solitary ancestors.

The effects of different ecophysiological factors on ochratoxin A production.

Mycotoxin biosynthesis is affected by peculiar agro-ecosystem dependent conditions. Accordingly, the correlation between mycotoxin contamination and environmental condition change scenarios should be carefully considered. This is because fungal colonization and mycotoxin contamination could critically impair the availability of food products, especially in poor countries. At any time, the agricultural products might become susceptible to fungal contamination and mycotoxin production in uncontrolled storage. From 2000 to 2010, many studies were carried out in the case of the effects of different parameters on ochratoxin A (OTA) production by fungi in order to avoid providing the appropriate conditions for producing OTA. Water activity (a(w)), temperature, type of species and the substrates were introduced as the most important in these articles. This paper reviews the major published articles regarding the different ecophysiological factors influencing on OTA production.