Juvenile hormone affects age polyethism, ovarian status and cuticular hydrocarbon profile in workers of the wasp Polybia occidentalis.

Division of labor is one of the most striking features in the evolution of eusociality. Juvenile hormone (JH) mediates reproductive status and aggression among nestmates in primitively eusocial Hymenoptera (species without morphologically distinct castes). In highly social species it has apparently lost its gonadotropic role and primarily regulates the division of labor in the worker caste.

Osmophores of Caryocar brasiliense (Caryocaraceae): a particular structure of the androecium that releases an unusual scent.

Caryocar brasiliense is a flagship species of the Brazilian Cerrado. It produces flowers with a strong peculiar scent, which are pollinated by bats and occasionally moths with short mouthparts. However, the cues responsible for attracting these nocturnal pollinators remain unknown.

Scientific Note: Warming Nurses, a New Worker Role Recorded for the First Time in Stingless Bees.

Nest temperature is a crucial variable that determines colony survival in social insects. The successful production and development of a new brood, therefore, depends on stable thermal conditions and limited temperature oscillations. Thermoregulatory processes are useful in controlling both individual activity and for the maintenance of colony temperature.

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

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.

The acceptance rate of young wasps by alien colonies depends on colony developmental stages in the swarm-founding wasp, Polybia paulista von ihering (Hymenoptera: Vespidae).

In social insects, newly emerged individuals learn the colony-specific chemical label from their natal comb shortly after their emergence. These labels help to identify each individual's colony of origin and are used as a recognition template against which individuals can discriminate nestmates from non-nestmates. Our previous studies with Polybia paulista von Ihering support this general pattern, and the acceptance rate of young female and male wasps decreased as a function of their age.

Nest thermoregulation in Polybia scutellaris (White) (Hymenoptera: Vespidae).

Polybia scutellaris (White) builds large nests characterized by numerous spiny projections on the surface. In order to determine whether or not the nest temperature is maintained because of homeothermic conditions of the nest individuals or otherwise, we investigated the thermal conditions within the nests built by P. scutellaris.

Castes in the neotropical social wasp Leipomeles dorsata (Fabricius) (Hymenoptera: Vespidae): a window for workers achieving a new status in the colony.

Morphometric studies performed in several species of Neotropical social wasps from the tribe Epiponini showed that in some species there are marked differences between castes, while other species present highly distinct castes with differences only in ovarian development. This work analyzed females from six colonies of the social wasp Leipomeles dorsata (Fabricius) in which queens (egglayers) and workers showed differences in ovarian development and coloration. We propose that wasps with developed ovaries (egglayers) and coloration similar to those of workers are possibly intermediates that obtained the status of queens in the colony.

Mandibular gland secretions of meliponine worker bees: further evidence for their role in interspecific and intraspecific defence and aggression and against their role in food source signalling.

Like ants and termites some species of stingless bees (Meliponini), which are very important pollinators in the tropics, use pheromone trails to communicate the location of a food source. We present data on the communicative role of mandibular gland secretions of Meliponini that resolve a recent controversy about their importance in the laying of such trails. Volatile constituents of the mandibular glands have been erroneously thought both to elicit aggressive/defensive behaviour and to signal food source location.

Castes and asynchronous colony cycle in Polybia bistriata (Fabricius) (Hymenoptera: Vespidae).

Neotropical swarm-founding wasps, the Epiponini, are an outstanding group of social insects whose societies are polygynic and complex nest builders. Caste dimorphism in these wasps ranges from incipient to highly distinct. Morphometric analyses of nine body parts, ovarian status, relative age and development of the 5th gastral sternite gland (Richards' gland) of Polybia bistriata Fabricius were undertaken in order to estimate caste differentiation in nine colonies.

Predatory behavior in a necrophagous bee Trigona hypogea (Hymenoptera; Apidae, Meliponini).

Although most bees feed on nectar and pollen, several exceptions have been reported. The strangest of all is the habit found in some neotropical stingless bees, which have completely replaced pollen-eating by eating animal protein from corpses. For more than 20 years, it was believed that carrion was the only protein source for these bees.