Nerol: An alarm substance of the stingless bee,Trigona fulviventris (Hymenoptera: Apidae)

Terpenoid-Induced Feeding Deterrence and Antennal Response of Honey Bees

Multiple interacting stressors negatively affect the survival and productivity of managed honey bee colonies. Pesticides remain a primary concern for beekeepers, as even sublethal exposures can reduce bee immunocompetence, impair navigation, and reduce social communication. Pollinator protection focuses on pesticide application guidelines; however, a more active protection strategy is needed. One possible approach is the use of feeding deterrents that can be delivered as an additive during pesticide application. The goal of this study was to validate a laboratory assay designed to rapidly screen compounds for behavioral changes related to feeding or feeding deterrence. The results of this investigation demonstrated that the synthetic Nasonov pheromone and its terpenoid constituents citral, nerol, and geraniol could alter feeding behavior in a laboratory assay. Additionally, electroantennogram assays revealed that these terpenoids elicited some response in the antennae; however, only a synthetic Nasonov pheromone, citral, and geraniol elicited responses that differed significantly from control and vehicle detections.

Mandibular glands of stingless bees (Hymenoptera: Apidae): Chemical analysis of their contents and biological function in two species ofMelipona

Workers ofMelipona fasciata andM. interrupta triplaridis respond to their respective mandibular gland extracts with alarm recruitment and defensive behavior. Workers rapidly exit from the nest entrance, land on an intruding object, and bite with the mandibles while vibrating the flight muscles. These behaviors are accompanied by the release of the contents of the mandibular glands. Colonies of both species exhibited greater response to their own mandibular gland extracts than to those of other stingless bee species. Chemical analysis identified 2-heptanol as the major component in hexane extracts of each species. Undecane was a constituent of both species; skatole and nerol were identified only in extracts ofM. i. triplaridis.

Alarm substances of the stingless bee,Trigona silvestriana

2-Nonanol, 2-heptanol, octyl decanoate, and octyl octanoate were identified from the heads ofTrigona silvestriana workers. When presented at the nest, 2-nonanol, 2-heptanol, and the mixture of the four compounds elicited angular flights, landing, and buzzing of guard bees. Octyl octanoate elicited a weaker response. No response was given to octyl decanoate, to the ether solvent, or to the control volatile, vanillin.

Defensive behavior of honey bees: organization, genetics, and comparisons with other bees

One key advantage of eusociality is shared defense of the nest, brood, and stored food; nest defense plays an important role in the biology of eusocial bees. Recent studies on honey bees, Apis mellifera, have focused on the placement of defensive activity in the overall scheme of division of labor, showing that guard bees play a unique and important role in colony defense. Alarm pheromones function in integrating defensive responses; honey bee alarm pheromone is an excellent example of a multicomponent pheromonal blend. The genetic regulation of defensive behavior is now better understood from the mapping of quantitative trait loci (QTLs) associated with variation in defensiveness. Colony defense in other eusocial bees is less well understood, but enough information is available to provide interesting comparisons between A. mellifera and other species of Apis, as well as with allodapine, halictine, bombine, and meliponine bees. These comparative studies illustrate the wide variety of evolutionary solutions to problems in colony defense in the Apoidea.

Secretions of stingless bees: cephalic secretions of two Frieseomelitta species

Gas chromatographic and mass spectrometric analysis of the volatile compounds in the mandibular glands of Frieseomelitta varia and the heads of Frieseomelitta silvestrii have revealed relatively simple or more complex mixtures of volatile oxygenated compounds. 2-Alkanols were found to be important components for both species. In F. varia the composition was essentially the same in samples from two widely separated areas and there were small differences between callows and mature, foraging bees. The first electroantennographic studies on stingless bees, using hexane extracts of heads of both species, have demonstrated a response in the workers' antennae to these, as well as to the pure compounds 2-heptanol and 2-nonanol.

Exocrine secretions of bees--VII. Aliphatic esters in the Dufour's gland secretion of Svastra obliqua obliqua (Hymenoptera: Anthophoridae)

The chemistry of the Dufour's gland secretion of Svastra obliqua obliqua is reported. A series of 32 aliphatic esters were identified. The Dufour's secretion of Svastra obliqua obliqua contains the most complex mixture of volatile compounds in bee extracts examined to date.