Queen signals in a stingless bee: suppression of worker ovary activation and spatial distribution of active compounds

Abstract

In most species of social insect the queen signals her presence to her workers via pheromones. Worker responses to queen pheromones include retinue formation around the queen, inhibition of queen cell production and suppression of worker ovary activation. Here we show that the queen signal of the Brazilian stingless bee Friesella schrottkyi is a mixture of cuticular hydrocarbons. Stingless bees are therefore similar to ants, wasps and bumble bees, but differ from honey bees in which the queen's signal mostly comprises volatile compounds originating from the mandibular glands. This shows that cuticular hydrocarbons have independently evolved as the queen's signal across multiple taxa, and that the honey bees are exceptional. We also report the distribution of four active queen-signal compounds by Matrix-assisted laser desorption/ionization (MALDI) imaging. The results indicate a relationship between the behavior of workers towards the queen and the likely site of secretion of the queen's pheromones.

Solitary bees reduce investment in communication compared with their social relatives

“…In highly social insects, queens produce a pheromone that signals their reproductive status and also inhibits worker reproduction (11)(12)(13)(14)(15). Some of these pheromones contain compounds that can be highly conserved across species, suggesting that there may be some aspects of these blends that have been coopted from the mating or defense signals of their solitary ancestors (16).…”

Evolution: A Royal Seal for Wasp Eggs

“…It now seems that non-volatile, saturated, long-chain cuticular hydrocarbons have been co-opted as the queen-presence, worker-sterilityinducing signal in all major groups of hymenopteran social insects (ants, wasps, bumble bees and stingless bees) except honey bees [16,17]. Eusociality evolved independently in ants, wasps and An 'anarchistic' honey bee worker laying an egg.…”

Reproductive regulation in an orchid bee: social context, fertility and chemical signalling

“…Our results clearly show that dominant females had higher proportions of n-alkanes than subordinates. The effects of the social environment on the cuticular profiles are particularly interesting here, given the apparently significant role of alkanes in suppressing ovarian activation in other bees (see van Oystaeyen et al, 2014).…”

“…The ethophysiological effects of putative queen pheromones have been demonstrated in workers of some species of ants, bees and wasps (Holman, Jørgensen, Nielsen, & d'Ettorre, 2010;Nunes et al, 2014;van Oystaeyen et al, 2014;van Zweden, Bonckaert, Wenseleers, & d'Ettorre, 2014). Recent evidence also indicates that the cuticular hydrocarbons of the queen pheromone are conserved over a range of eusocial taxa, suggesting that the fertility-associated signal is an ancestral trait, and was probably present in the ancestral solitary insects that gave rise to the social insects (van Oystaeyen et al, 2014).…”

“…Despite the existence of an extensive database for bumblebees (Ayasse et al, 1999), honeybees (Wossler & Crewe, 1999) and stingless bees (Nunes et al, 2014), no evidence is available on the possible chemical modulation of social relationships in bees of the genus Euglossa. In this study, we investigated which factors contribute to the social structure of the nest of an orchid bee, Euglossa melanotricha.…”