Geraldine Wright

Newcastle University | NCL · Institute of Neuroscience

Bees are important pollinators of agricultural crops, but their populations are at risk when pesticides are used. One of the largest risks bees face is poisoning of floral nectar and pollen by insecticides. Studies of bee detection of neonicotinoids have reported contradictory evidence about whether bees can taste these pesticides in sucrose soluti...

Bees are important pollinators of agricultural crops, but their populations are at risk when pesticides are used. One of the largest risks bees face is poisoning of floral nectar and pollen by insecticides. Studies of bee detection of neonicotinoids have reported contradictory evidence about whether bees can taste these pesticides in sucrose soluti...

Bees are important pollinators of agricultural crops, but their populations are at risk when pesticides are used. One of the largest risks bees face is poisoning of floral nectar and pollen by insecticides. Studies of bee detection of neonicotinoids have reported contradictory evidence about whether bees can taste these pesticides in sucrose soluti...

ELife digest Bees and other pollinators often encounter pesticides while collecting nectar and pollen from agricultural crops. Widely used to protect crops, pesticides are toxic to insects and have contributed to population declines in all bee species. One way that bees might be able to avoid pesticides is using their incredibly good sense of taste...

Background Bees provide essential pollination services for many food crops and are critical in supporting wild plant diversity. However, the dietary landscape of pollen food sources for social and solitary bees has changed because of agricultural intensification and habitat loss. For this reason, understanding the basic nutrient metabolism and meet...

Bees are important pollinators of agricultural crops, but their populations are at risk when pesticides are used. One of the largest risks bees face is poisoning of floral nectar and pollen by insecticides. Studies of bee detection of neonicotinoids have reported contradictory evidence about whether bees can taste these pesticides in sucrose soluti...

The sense of taste permits the recognition of valuable nutrients and the avoidance of potential toxins. Previously, we found that bumblebees have a specialized mechanism for sensing sugars whereby two gustatory receptor neurons (GRNs) within the galeal sensilla of the bees’ mouthparts exhibit burst of spikes. Here, we show that the temporal firing...

Phytosterols are primary plant metabolites that have fundamental structural and regulatory functions. They are also essential nutrients for phytophagous insects, including pollinators, that cannot synthesize sterols. Despite the well‐described composition and diversity in vegetative plant tissues, few studies have examined phytosterol diversity in...

Essential macronutrients are critical to the fitness and survival of animals. Many studies have shown that animals regulate the amount of protein and carbohydrate they eat for optimal performance. Regulation of dietary fat is important but less often studied. Honeybees collect and consume floral pollen to obtain protein and fat but how they achieve...

Flower-visiting insects are important crop pollinators, but their populations in agricultural landscapes are declining. One reason is the decreasing quantity and quality of floral resources. Deterioration of the situation caused by an increasing production of energy crops like maize, a pollen-only resource, may be mitigated by alternative crops suc...

Honey bees feed on floral nectar and pollen that they store in their colonies as honey and bee bread. Social division of labor enables the collection of stores of food that are consumed by within-hive bees that convert stored pollen and honey into royal jelly. Royal jelly and other glandular secretions are the primary food of growing larvae and of...

Sufficiently diverse and abundant resources are essential for generalist consumers, and form an important part of a suite of conservation strategies for pollinators. Honey bees are generalist foragers and are dependent on diverse forage to adequately meet their nutritional needs. Through analysis of stored pollen (bee bread) samples obtained from 2...

Floral nectar is a reward offered by flowering plants to visiting pollinators. Nectar chemistry is important for understanding plant nutrient allocation and plant–pollinator interactions. However, many plant species are difficult to sample as their flowers are small and produce low amounts of nectar. We compared the effects of different methods of...

Pollen provides floral visitors with essential nutrients including proteins, lipids, vitamins and minerals. As an important nutrient resource for pollinators, including honeybees and bumblebees, pollen quality is of growing interest in assessing available nutrition to foraging bees. To date, quantifying the protein‐bound amino acids in pollen has b...

Toxic nectar is an ecological paradox [1, 2]. Plants divert substantial resources to produce nectar that attracts pollinators [3], but toxins in this reward could disrupt the mutualism and reduce plant fitness [4]. Alternatively, such compounds could protect nectar from robbers [2], provided that they do not significantly alter pollinator visitatio...

One of the most important tasks of the brain is to learn and remember information associated with food. Studies in mice and Drosophila have shown that sugar rewards must be metabolisable to form lasting memories, but few other animals have been studied. Here, we trained adult, worker honeybees (Apis mellifera) in two olfactory tasks (massed and spa...

Gustatory receptors (Grs) expressed in insect taste neurons signal the presence of carbohydrates, sugar alcohols, CO2, bitter compounds and oviposition stimulants. The honeybee (Apis mellifera) has one of the smallest Gr gene sets (12 Gr genes) of any insect whose genome has been sequenced. Honeybees live in eusocial colonies with a division of lab...

Apis mellifera gustatory receptor gene information and associated primers. (DOCX)

Expression levels in internal tissues of most gustatory receptor mRNA is greatest in the forager honeybee brain. Expression of mRNA for Apis mellifera gustatory receptors (AmGr): in newly-emerged and forager bees, brain and gut tissues A. AmGr1 (N = 3–4 biological replicates), B. AmGr2 (N = 3–4 biological replicates), C. AmGr3 (N = 4 biological rep...

Raw Ct values from the RT-qPCR for the two reference genes Ribosomal Protein 49 (RP49) and Ribosomal protein S8 (RPS8) showing relatively stable expression across all assessed body parts of forager (~2–3 weeks old) and newly emerged (~24 h old) honeybees. Body parts: Brain (N = 20 pooled tissues), Gut (20 pooled tissues), Ant: antenna (N = 150 pool...

Expression levels of the 10 honeybee gustatory receptor genes across the un-manipulated forager (≈2–3 wk old) and newly emerged honeybee (≈24 h old) anatomy, as seen in Table 1, relative to RPS8 as a reference gene (NA represents unavailable data). (TIF)

The effect of environmental pollutants on honeybee behaviour has focused mainly on currently used pesticides. However, honeybees are also exposed to persistent organic pollutants (POPs). The aim of this laboratory based study was to determine if exposure to sublethal field-relevant concentrations of POPs altered the spontaneous behaviour of foragin...

The ecological function of secondary metabolites in plant defence against herbivores is well established, but their role in plant–pollinator interactions is less obvious. Nectar is the major reward for pollinators, so the occurrence of defence chemicals in the nectar of many species is unexpected. However, increasing evidence supports a variety of...

1. Secondary compounds in nectar can function as toxic chemical defences against floral antagonists, but may also mediate plant-pollinator interactions. Despite their ecological importance, few studies have investigated patterns of spatial variation in toxic nectar compounds in plant species, and none outside their native range. 2. Grayanotoxin I...

Invasive species are considered a main driver of pollinator declines, yet the direct effects of invasive alien plants on pollinators are poorly understood. Abundant, invasive plant species can provide a copious nectar resource for native pollinators. However, the nectar of some plants contains secondary compounds, usually associated with defence ag...

Neonicotinoids are often applied as systemic seed treatments to crops and have reported negative impact on pollinators when they appear in floral nectar and pollen. Recently, we found that bees in a two-choice assay prefer to consume solutions containing field-relevant doses of the neonicotinoid pesticides, imidacloprid (IMD) and thiamethoxam (TMX)...

To avoid poisoning and death when toxins are ingested, the body responds with a suite of physiological detoxification mechanisms accompanied by behaviours that in mammals often include vomiting, nausea, and lethargy. Few studies have characterised whether insects exhibit characteristic ‘malaise-like’ behaviours in response to intoxication. Here, we...

Sodium channels, found ubiquitously in animal muscle cells and neurons, are one of the main target sites of many naturally-occurring, insecticidal plant compounds and agricultural pesticides. Pyrethroids, derived from compounds found only in the Asteraceae, are particularly toxic to insects and have been successfully used as pesticides including on...

The impact of neonicotinoid insecticides on insect pollinators is highly controversial. Sublethal concentrations alter the behaviour of social bees and reduce survival of entire colonies. However, critics argue that the reported negative effects only arise from neonicotinoid concentrations that are greater than those found in the nectar and pollen...

Fruit flies love foods containing yeast. A new study now shows that they are attracted to and have dedicated olfactory neurons for detecting the scents produced by yeast metabolizing common phenolic compounds in fruit. Copyright © 2015 Elsevier Ltd. All rights reserved.

Animals strongly regulate the amount of protein that they consume. The quantity of individual essential amino acids (EAAs) obtained from dietary protein depends on the protein source, but how much EAA proportions in diet affect nutrient balancing has been rarely studied. Recent research using the Geometric Framework for nutrition has revealed that...

Characterizing bee patterns of visitation to host-plants is challenging because of many factors (floral traits, ecological conditions, experience) influencing foraging decision-making. Ultimately, however, bees must forage for floral resources as their sole source of nutrition and may have species-specific nutrient requirements for optimal growth....

Background/Question/Methods Floral nectar commonly contains plant secondary compounds (SC) that may be deterrent or toxic to insects and are usually associated with defense against herbivory elsewhere in the plant. Studies of nectar SCs have included investigations of function, impacts on plant fitness and on flower-visitor health. No work to dat...

Evidence is accumulating that commonly used pesticides are linked to decline of pollinator populations; adverse effects of three neonicotinoids on bees have led to bans on their use across the European Union. Developing insecticides that pose negligible risks to beneficial organisms such as honeybees is desirable and timely. One strategy is to use...

Systemic pesticides such as neonicotinoids are commonly used on flowering crops visited by pollinators, and their use has been implicated in the decline of insect pollinator populations in Europe and North America. Several studies show that neonicotinoids affect navigation and learning in bees but few studies have examined whether these substances...

Obtaining the correct balance of nutrients requires that the brain integrates information about the body's nutritional state with sensory information from food to guide feeding behaviour. Learning is a mechanism that allows animals to identify cues associated with nutrients so that they can be located quickly when required. Feedback about nutrition...

Dietary essential amino acids have an important influence on the lifespan and fitness of animals. The expression of the NAD+-dependent histone deacetylase, Sir2, can be influenced by diet, but its role in the extension of lifespan has recently been challenged. Here, we used the honeybee to test how the dietary balance of carbohydrates and essential...

Dietary sources of essential amino acids (EAAs) are used for growth, somatic maintenance and reproduction. Eusocial insect workers such as honeybees are sterile, and unlike other animals, their nutritional needs should be largely dictated by somatic demands that arise from their role within the colony. Here, we investigated the extent to which the...

Bees visit flowers to collect nectar and pollen that contain nutrients and simultaneously facilitate plant sexual reproduction. Paradoxically, nectar produced to attract pollinators often contains deterrent or toxic plant compounds associated with herbivore defence. The functional significance of these nectar toxins is not fully understood, but the...

Serotonin (5-hydroxytryptamine, 5-HT) is involved in the regulation of feeding and digestion in many animals from worms to mammals. In insects, 5-HT functions both as a neurotransmitter and as a systemic hormone. Here we tested its role as a neurotransmitter in feeding and crop contractions and its role as a systemic hormone that affected feeding i...

Nutrition plays an important role in physiological stress resistance and by adjusting their intake of key nutrients, such as protein and carbohydrate, many animals can better resist stress. Poor nutrition may contribute to the widespread and on-going declines of honeybee populations by increasing their vulnerability to abiotic (e.g. pesticides) an...

Elucidating the cellular and molecular basis of nutrient metabolism and regulation of feeding has become a major focus in scientific research over the last twenty years. Because of the increasing number of overweight and obese people in western and other societies, research efforts have initially been directed towards the basic metabolic processes...

Insect pollinators of crops and wild plants are under threat globally and their decline or loss could have profound economic and environmental consequences. Here, we argue that multiple anthropogenic pressures – including land-use intensification, climate change, and the spread of alien species and diseases – are primarily responsible for insect-po...

Pesticides that target cholinergic neurotransmission are highly effective, but their use has been implicated in insect pollinator population decline. Honeybees are exposed to two widely used classes of cholinergic pesticide: neonicotinoids (nicotinic receptor agonists) and organophosphate miticides (acetylcholinesterase inhibitors). Although sublet...

Bees Get That Caffeine "Buzz" Caffeine improves memory in humans, millions of whom find that their daily dose enhances clarity, focus, and alertness. The human relationship with caffeine is relatively recent, however, and thus its impact on our brains is likely a by-product of its true ecological role. Caffeine occurs naturally in the floral nectar...

Chemosensory information is crucial for most insects to feed and reproduce. Olfactory signals are mainly used at a distance, whereas gustatory stimuli play an important role when insects directly contact chemical substrates. In noctuid moths, although the antennae are the main olfactory organ, they also bear taste sensilla. These taste sensilla det...

Pesticides are important agricultural tools often used in combination to avoid resistance in target pest species, but there is growing concern that their widespread use contributes to the decline of pollinator populations. Pollinators perform sophisticated behaviours while foraging that require them to learn and remember floral traits associated wi...

Cholinergic signaling is fundamental to neuromuscular function in most organisms. Sub-lethal doses of neurotoxic pesticides that target cholinergic signaling can alter the behavior of insects in subtle ways; their influence on non-target organisms may not be readily apparent in simple mortality studies. Beneficial arthropods such as honeybees perfo...

Nosema ceranae is spreading into areas where Nosema apis already exists. N. ceranae has been reported to cause an asymptomatic infection that may lead, ultimately, to colony collapse. It is thought that there may be a temperature barrier to its infiltration into countries in colder climates. In this study, 71 colonies from Scottish Beekeeper's Asso...

Size distribution of Nosema spores identified in Scotland using larger dataset. a Samples were distributed into two groups [group A (221 spores); samples 31, 34 and 66] and [group B (171 spores); samples15, 17, 18, and 42] based on size differences determined by ANOVA (Kruskal–Wallis; Dunnett’s post hoc test) and analyzed for length, width and squa...

The decline of honeybees and other pollinating insects is a current cause for concern. A major factor implicated in their decline is exposure to agricultural chemicals, in particular the neonicotinoid insecticides such as imidacloprid. Honeybees are also subjected to additional chemical exposure when beekeepers treat hives with acaricides to combat...

Complex odours often possess perceptual qualities that are distinct from their components. Previous studies in humans, rodents, and insects indicate that the perception of complex odour blends depends on the concentration of the components and the mixture's complexity. However, we know relatively little about the way that an odour mixture 'gestalt'...

Caffeine affects several molecules that are also involved in the processes underlying learning and memory such as cAMP and calcium. However, studies of caffeine's influence on learning and memory in mammals are often contradictory. Invertebrate model systems have provided valuable insight into the actions of many neuroactive compounds including eth...

Physiological state profoundly influences the expression of the behaviour of individuals and can affect social interactions between animals. How physiological state influences food sharing and social behaviour in social insects is poorly understood. Here, we examined the social interactions and food sharing behaviour of honeybees with the aim of de...

Data for Donors and Receivers. (XLSX)

Social behaviour of receivers towards 1.0 M sucrose-fed and 5% ethanol-fed donors. (A,B) The number of bouts of antennation remained constant during the interval (Pois. Reg χ52 = 6.65, p = 0.248), and was not significantly affected by the treatment (Pois. Reg χ12 = 3.31, p = 0.069). Mean bout duration of antennation changed over the interval for th...

Canonical Discriminant Analysis for Individual Motor Behaviours. (DOCX)

Individual behaviours of receivers towards 1.0 M sucrose-fed and 5% ethanol-fed donors. (A, B) The receivers performed more bouts of walking later in the interval (Pois. Reg. χ52 = 12.3, p = 0.031), but there was no effect of treatment (Pois. Reg χ12 = 1.05, p = 0.307). The average bout duration for the stopped behaviour did not change during the i...

Factor Analysis for All Behavioural Variables. (DOCX)

Canonical Discriminant Analysis for Social Behaviours. (DOCX)

Whether animals experience human-like emotions is controversial and of immense societal concern [1–3]. Because animals cannot provide subjective reports of how they feel, emotional state can only be inferred using physiological, cognitive, and behavioral measures [4–8]. In humans, negative feelings are reliably correlated with pessimistic cognitive...

Recent studies of the way animals learn challenge the idea that food learning relies mainly on how food tastes. Work on Drosophila has now shown that flies must ingest food with a metabolic benefit to form a lasting memory for a learned odour.

For most animals, eating entails the risk of being poisoned. Learning how to identify foods with toxins is an important mechanism that reduces the risk of poisoning. While conditioned food aversions have been studied in vertebrates for over 50 years, the neural circuits underlying this form of learning have been difficult to elucidate because of th...

Avoiding toxins in food is as important as obtaining nutrition. Conditioned food aversions have been studied in animals as diverse as nematodes and humans [1, 2], but the neural signaling mechanisms underlying this form of learning have been difficult to pinpoint. Honeybees quickly learn to associate floral cues with food [3], a trait that makes th...

Latent inhibition refers to learning that some stimuli are not signals of important events. It has been widely studied in vertebrates, but it has been substantially less well studied in invertebrates. We present an investigation into latent inhibition in the honey bee (Apis mellifera) using a proboscis extension response conditioning procedure that...

1. The evolution of flowering plants has undoubtedly been influenced by a pollinator’s ability to learn to associate floral signals with food. Here, we address the question of ‘why’ flowers produce scent by examining the ways in which olfactory learning by insect pollinators could influence how floral scent emission evolves in plant populations. 2....

Recent studies have provided a new perspective on the relationship between the honey bee queen and her colony. They suggest that the queen produces a pheromone which pharmacologically manipulates her workers.

Plants produce flowers with complex visual and olfactory signals, but we know relatively little about the way that signals such as floral scents have evolved. One important factor that may direct the evolution of floral signals is a pollinator's ability to learn. When animals learn to associate two similar signals with different outcomes, biases in...

Animals sample sensory stimuli for longer periods when they must perform difficult discrimination tasks, implying that the brain's ability to represent stimuli improves as a function of time. Although it is true in other senses, few studies have examined whether increasing sampling time improves olfactory discrimination. In the experiments reported...

Invertebrates are valuable models for increasing our understanding of the effects of ethanol on the nervous system, but most studies on invertebrates and ethanol have focused on the effects of ethanol on locomotor behavior. In this work we investigate the influence of an acute dose of ethanol on appetitive olfactory learning in the honey bee (Apis...

Locusts have two large collision-detecting neurons, the descending contralateral movement detectors (DCMDs) that signal object approach and trigger evasive glides during flight. We sought to investigate whether vision for action, when the locust is in an aroused state rather than a passive viewer, significantly alters visual processing in this coll...

[This corrects the article on p. e1704 in vol. 3, PMID: 18301779.].

Animals use odors as signals for mate, kin, and food recognition, a strategy which appears ubiquitous and successful despite the high intrinsic variability of naturally-occurring odor quantities. Stimulus generalization, or the ability to decide that two objects, though readily distinguishable, are similar enough to afford the same consequence, cou...

Animals possess the ability to assess food quality via taste and via changes in state that occur after ingestion. Here, we investigate the extent to which a honey bee's ability to assess food quality affected the formation of association with an odor stimulus and the retention of olfactory memories associated with reward. We used three different co...