Physiology of reproductive worker honey bees (Apis mellifera): insights for the development of the worker caste.

Reproductive and behavioural specialisations characterise advanced social insect societies. Typically, the honey bee (Apis mellifera) shows a pronounced reproductive division of labour between worker and queen castes, and a clear division of colony roles among workers. In a queenless condition, however, both of these aspects of social organisation break down.

Cocaine affects foraging behaviour and biogenic amine modulated behavioural reflexes in honey bees.

In humans and other mammals, drugs of abuse alter the function of biogenic amine pathways in the brain leading to the subjective experience of reward and euphoria. Biogenic amine pathways are involved in reward processing across diverse animal phyla, however whether cocaine acts on these neurochemical pathways to cause similar rewarding behavioural effects in animal phyla other than mammals is unclear. Previously, it has been shown that bees are more likely to dance (a signal of perceived reward) when returning from a sucrose feeder after cocaine treatment.

Altruistic behavior by egg-laying worker honeybees.

If a honeybee (Apis mellifera) colony loses its queen, worker bees develop their ovaries and produce male offspring [1]. Kin selection theory predicts that the degree of altruism in queenless colonies should be reduced because the relatedness of workers to a hivemate's offspring is less in queenless colonies than it is to the daughters of the queen in queenright colonies [2-4]. To explore this hypothesis, we examined the behavior and physiology of queenless egg-laying workers.

General Stress Responses in the Honey Bee.

The biological concept of stress originated in mammals, where a "General Adaptation Syndrome" describes a set of common integrated physiological responses to diverse noxious agents. Physiological mechanisms of stress in mammals have been extensively investigated through diverse behavioral and physiological studies. One of the main elements of the stress response pathway is the endocrine hypothalamo-pituitary-adrenal (HPA) axis, which underlies the "fight-or-flight" response via a hormonal cascade of catecholamines and corticoid hormones.

Regional changes in the cholinergic system in mice lacking monoamine oxidase A.

Elevated brain monoamine concentrations resulting from monoamine oxidase A genetic ablation (MAOA knock-out mice) lead to changes in other neurotransmitter systems. To investigate the consequences of MAOA deficiency on the cholinergic system, we measured ligand binding to the high-affinity choline transporter (CHT1) and to muscarinic and nicotinic receptors in brain sections of MAOA knock-out (KO) and wild-type mice. A twofold increase in [(3)H]-hemicholinium-3 ([(3)H]-HC-3) binding to CHT1 was observed in the caudate putamen, nucleus accumbens, and motor cortex in MAOA KO mice as compared with wild-type (WT) mice.

Regional differential effects of chronic nicotine on brain alpha 4-containing and alpha 6-containing receptors.

Chronic nicotine upregulates central nicotinic acetylcholine receptors (nAChRs), a plasticity process thought to contribute to its addictive properties. To analyze this process in vivo, we chronically exposed mice to nicotine using minipump delivering nicotine at concentrations close to those found in tobacco smokers. Binding studies show upregulation of high-affinity nAChRs after 21 days of treatment in cortical areas, caudate putamen, nucleus accumbens, hippocampus, ventral tegmental area, and superior colliculi.