95 results on '"Gronenberg W"'
Search Results
2. Afferent projections of infrared-sensitive sensilla in the beetle Melanophila acuminata (Coleoptera: Buprestidae)
- Author
-
Gronenberg, W. and Schmitz, Helmut
- Published
- 1999
- Full Text
- View/download PDF
3. Fast actions in small animals: springs and click mechanisms
- Author
-
Gronenberg, W.
- Published
- 1996
- Full Text
- View/download PDF
4. The fast mandible strike in the trap-jaw ant Odontomachus: I. Temporal properties and morphological characteristics
- Author
-
Gronenberg, W.
- Published
- 1995
- Full Text
- View/download PDF
5. The fast mandible strike in the trap-jaw ant Odontomachus: II. Motor control
- Author
-
Gronenberg, W.
- Published
- 1995
- Full Text
- View/download PDF
6. The sensory basis for the trap-jaw mechanism in the ant Odontomachus bauri
- Author
-
Gronenberg, W. and Tautz, J.
- Published
- 1994
- Full Text
- View/download PDF
7. Alometría cerebral y plasticidad neuronal en el abejorro Bombus occidentalis
- Author
-
Riveros , Andre J. and Gronenberg, W.
- Subjects
Cognition ,fungi ,Honeybee ,Brain size ,Bombus - Abstract
Brain plasticity is a common phenomenon across animals and in many cases it is associated with behavioral transitions. In social insects, such as bees, wasps and ants, plasticity in a particular brain compartment involved in multisensory integration (the mushroom body) has been associated with transitions between tasks differing in cognitive demands. However, in most of these cases, transitions between tasks are age-related, requiring the experimental manipulation of the age structure in the studied colonies to distinguish age and experience-dependent effects. To better understand the interplay between brain plasticity and behavioral performance it would therefore be advantageous to study species whose division of labor is not age-dependent. Here, we focus on brain plasticity in the bumblebee Bombus occidentalis, in which division of labor is strongly affected by the individual’s body size instead of age. We show that, like in vertebrates, body size strongly correlates with brain size. We also show that foraging experience, but not age, significantly correlates with the increase in the size of the mushroom body, and in particular one of its components, the medial calyx. Our results support previous findings from other social insects suggesting that the mushroom body plays a key role in experience-based decision making. We also discuss the use of bumblebees as models to analyze neural plasticity and the association between brain size and behavioral performance.
- Published
- 2010
8. The Evolution of Body Size, Antennal Size and Host Use in Parasitoid Wasps (Hymenoptera: Chalcidoidea): A Phylogenetic Comparative Analysis
- Author
-
Gronenberg, W, Symonds, MRE, Elgar, MA, Gronenberg, W, Symonds, MRE, and Elgar, MA
- Abstract
Chalcidoid wasps represent one of the most speciose superfamilies of animals known, with ca. 23,000 species described of which many are parasitoids. They are extremely diverse in body size, morphology and, among the parasitoids, insect hosts. Parasitic chalcidoids utilise a range of behavioural adaptations to facilitate exploitation of their diverse insect hosts, but how host use might influence the evolution of body size and morphology is not known in this group. We used a phylogenetic comparative analysis of 126 chalcidoid species to examine whether body size and antennal size showed evolutionary correlations with aspects of host use, including host breadth (specificity), host identity (orders of insects parasitized) and number of plant associates. Both morphological features and identity of exploited host orders show strong phylogenetic signal, but host breadth does not. Larger body size in these wasps was weakly associated with few plant genera, and with more specialised host use, and chalcidoid wasps that parasitize coleopteran hosts tend to be larger. Intriguingly, chalcidoid wasps that parasitize hemipteran hosts are both smaller in size in the case of those parasitizing the suborder Sternorrhyncha and have relatively larger antennae, particularly in those that parasitize other hemipteran suborders. These results suggest there are adaptations in chalcidoid wasps that are specifically associated with host detection and exploitation.
- Published
- 2013
9. The Processing of Color, Motion, and Stimulus Timing Are Anatomically Segregated in the Bumblebee Brain
- Author
-
Paulk, A. C., primary, Phillips-Portillo, J., additional, Dacks, A. M., additional, Fellous, J.-M., additional, and Gronenberg, W., additional
- Published
- 2008
- Full Text
- View/download PDF
10. Ant mushroom bodies reflect living conditions and species specific behavior
- Author
-
Gronenberg, W, primary
- Published
- 1999
- Full Text
- View/download PDF
11. Optimizing force and velocity: mandible muscle fibre attachments in ants
- Author
-
Paul, J., primary and Gronenberg, W., additional
- Published
- 1999
- Full Text
- View/download PDF
12. Age-dependent and task-related morphological changes in the brain and the mushroom bodies of the ant Camponotus floridanus
- Author
-
Gronenberg, W, primary, Heeren, S, additional, and Hölldobler, B, additional
- Published
- 1996
- Full Text
- View/download PDF
13. The trap-jaw mechanism in the dacetine ants Daceton armigerum and Strumigenys sp.
- Author
-
Gronenberg, W, primary
- Published
- 1996
- Full Text
- View/download PDF
14. The control of mandible movements in the ant Odontomachus
- Author
-
Just, S. and Gronenberg, W.
- Published
- 1999
- Full Text
- View/download PDF
15. Jaws that snap: control of mandible movements in the ant Mystrium
- Author
-
Gronenberg, W., Hoelldobler, B., and Alpert, G. D.
- Published
- 1998
- Full Text
- View/download PDF
16. Trail communication in the ant Megaponera foetens (Fabr.) (Formicidae, Ponerinae)
- Author
-
Hoelldobler, B., Braun, U., Gronenberg, W., and Kirchner, W. H.
- Published
- 1994
- Full Text
- View/download PDF
17. Brain size scaling through development in the whitelined sphinx moth (Hyles lineata) shows mass and cell number comparable to flies, bees, and wasps.
- Author
-
Aksamit IC, Dorigão-Guimarães F, Gronenberg W, and Godfrey RK
- Subjects
- Bees, Animals, Drosophila melanogaster, Organ Size, Larva, Cell Count, Wasps, Moths
- Abstract
Factors regulating larval growth and determinants of adult body size are described for several holometabolous insects, but less is known about brain size scaling through development. Here we use the isotropic fractionation ("brain soup") method to estimate the number of brain cells and cell density for the whitelined sphinx moth (Lepidoptera: Hyles lineata) from the first instar through the adult stage. We measure mass and brain cell number and find that, during the larval stages, body mass shows an exponential relationship with head width, while the total number of brain cells increases asymptotically. Larval brain cell number increases by a factor of ten from nearly 8000 in the first instar to over 80,000 in the fifth instar. Brain cell number increases by another factor of 10 during metamorphosis, with the adult brain containing more than 900,000 cells. This is similar to increases during development in the vinegar fly (Drosophila melanogaster) and the black soldier fly (Hermetia illucens). The adult brain falls slightly below the brain-to-body allometry for wasps and bees but is comparable in the number of cells per unit brain mass, indicating a general conservation of brain cell density across these divergent lineages., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
18. The flavonoid rutin protects the bumble bee Bombus impatiens against cognitive impairment by imidacloprid and fipronil.
- Author
-
Riveros AJ and Gronenberg W
- Subjects
- Animals, Bees, Flavonoids, Imidazoles toxicity, Neonicotinoids toxicity, Nitro Compounds, Pyrazoles, Rutin pharmacology, Cognitive Dysfunction, Insecticides toxicity
- Abstract
The ongoing decline of bee populations and its impact on food security demands integrating multiple strategies. Sublethal impairments associated with exposure to insecticides, affecting the individual and the colony levels, have led to insecticide moratoria and bans. However, legislation alone is not sufficient and remains a temporary solution to an evolving market of insecticides. Here, we asked whether bees can be prophylactically protected against sublethal cognitive effects of two major neurotoxic insecticides, imidacloprid and fipronil, with different mechanisms of action. We evaluated the protective effect of the prophylactic administration of the flavonoid rutin, a secondary plant metabolite, present in nectar and pollen, and known for its neuroprotective properties. Following controlled or ad libitum administration of rutin, foragers of the North American bumble bee Bombus impatiens received oral administration of the insecticides at sublethal realistic dosages. Learning acquisition, memory retention and decision speed were evaluated using olfactory absolute conditioning of the proboscis extension response. We show that the insecticides primarily impair acquisition but not retention or speed of the conditioned proboscis extension response. We further show that the administration of the flavonoid rutin successfully protects the bees against impairments produced by acute and chronic administration of insecticides. Our results suggest a new avenue for the protection of bees against sublethal cognitive effects of insecticides., Competing Interests: Competing interests Part of the results presented here are included in the PCT application W02021046388A1., (© 2022. Published by The Company of Biologists Ltd.)
- Published
- 2022
- Full Text
- View/download PDF
19. The central nervous system of whip spiders (Amblypygi): Large mushroom bodies receive olfactory and visual input.
- Author
-
Sinakevitch I, Long SM, and Gronenberg W
- Subjects
- Animals, Central Nervous System anatomy & histology, Central Nervous System cytology, Olfactory Pathways physiology, Scorpions physiology, Visual Pathways physiology, Mushroom Bodies cytology, Olfactory Pathways cytology, Scorpions anatomy & histology, Visual Pathways cytology
- Abstract
Whip spiders (Amblypygi) are known for their nocturnal navigational abilities, which rely on chemosensory and tactile cues and, to a lesser degree, on vision. Unlike true spiders, the first pair of legs in whip spiders is modified into extraordinarily long sensory organs (antenniform legs) covered with thousands of mechanosensory, olfactory, and gustatory sensilla. Olfactory neurons send their axons through the leg nerve into the corresponding neuromere of the central nervous system, where they terminate on a particularly large number (about 460) of primary olfactory glomeruli, suggesting an advanced sense of smell. From the primary glomeruli, olfactory projection neurons ascend to the brain and terminate in the mushroom body calyx on a set of secondary olfactory glomeruli, a feature that is not known from olfactory pathways of other animals. Another part of the calyx receives visual input from the secondary visual neuropil (the medulla). This calyx region is composed of much smaller glomeruli ("microglomeruli"). The bimodal input and the exceptional size of their mushroom bodies may support the navigational capabilities of whip spiders. In addition to input to the mushroom body, we describe other general anatomical features of the whip spiders' central nervous system., (© 2020 Wiley Periodicals LLC.)
- Published
- 2021
- Full Text
- View/download PDF
20. Allometric analysis of brain cell number in Hymenoptera suggests ant brains diverge from general trends.
- Author
-
Godfrey RK, Swartzlander M, and Gronenberg W
- Subjects
- Animals, Bees, Brain, Cell Count, Primates, Ants, Hymenoptera, Wasps
- Abstract
Many comparative neurobiological studies seek to connect sensory or behavioural attributes across taxa with differences in their brain composition. Recent studies in vertebrates suggest cell number and density may be better correlated with behavioural ability than brain mass or volume, but few estimates of such figures exist for insects. Here, we use the isotropic fractionator (IF) method to estimate total brain cell numbers for 32 species of Hymenoptera spanning seven subfamilies. We find estimates from using this method are comparable to traditional, whole-brain cell counts of two species and to published estimates from established stereological methods. We present allometric scaling relationships between body and brain mass, brain mass and nuclei number, and body mass and cell density and find that ants stand out from bees and wasps as having particularly small brains by measures of mass and cell number. We find that Hymenoptera follow the general trend of smaller animals having proportionally larger brains. Smaller Hymenoptera also feature higher brain cell densities than the larger ones, as is the case in most vertebrates, but in contrast with primates, in which neuron density remains rather constant across changes in brain mass. Overall, our findings establish the IF as a useful method for comparative studies of brain size evolution in insects.
- Published
- 2021
- Full Text
- View/download PDF
21. Learning of bimodal versus unimodal signals in restrained bumble bees.
- Author
-
Riveros AJ, Leonard AS, Gronenberg W, and Papaj DR
- Subjects
- Animals, Bees, Flowers, Odorants, Learning, Smell
- Abstract
Similar to animal communication displays, flowers emit complex signals that attract pollinators. Signal complexity could lead to higher cognitive load for pollinators, impairing performance, or might benefit them by facilitating learning, memory and decision making. Here, we evaluated learning and memory in foragers of the bumble bee Bombus impatiens trained to simple (unimodal) versus complex (bimodal) signals under restrained conditions. Use of a proboscis extension response protocol enabled us to control the timing and duration of stimuli presented during absolute and differential learning tasks. Overall, we observed broad variation in performance under the two conditions, with bees trained to compound bimodal signals learning and remembering as well as, better than or more poorly than bees trained to unimodal signals. Interestingly, the outcome of training was affected by the specific colour-odour combination. Among unimodal stimuli, the performance with odour stimuli was higher than with colour stimuli, suggesting that olfactory signals played a more significant role in the compound bimodal condition. This was supported by the fact that after 24 h, most bimodal-treatment bees responded to odour but not visual stimuli. We did not observe differences in latency of response, suggesting that signal composition affected decision accuracy, not speed. We conclude that restrained bumble bee workers exhibit broad variation of responses to bimodal stimuli and that components of the bimodal signal may not be used equivalently. The analysis of bee performance under restrained conditions enables accurate control of the multimodal stimuli provided to individuals and to study the interaction of individual components within a compound., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2020. Published by The Company of Biologists Ltd.)
- Published
- 2020
- Full Text
- View/download PDF
22. Linking Colony Size with Foraging Behavior and Brain Investment in Odorous Ants (Formicidae: Dolichoderinae).
- Author
-
Godfrey RK and Gronenberg W
- Subjects
- Animals, Ants physiology, Appetitive Behavior physiology, Behavior, Animal physiology, Brain anatomy & histology, Exploratory Behavior physiology, Organ Size physiology, Social Behavior
- Abstract
Superorganisms represent a unique level of biological organization in which the phenotype of the reproductive unit, the colony, results from traits expressed at the level of individual workers. Because body size scaling has important consequences for cell diversity and system complexity in solitary organisms, colony size is a trait of particular interest in superorganism evolution. In some instances, division of labor and worker polymorphism scale with colony size, but in general little is known about how colony size drives differences in individual-level behavior or neural traits. Ants represent the greatest diversity of superorganisms and provide a manner of natural experiment to test trends in trait evolution across multiple instances of colony size expansion. In this study, we control for environmental differences and worker size polymorphism to test if colony size correlates with measures of foraging behavior and brain size in dolichoderine ants. We present data from 3 species ranked by colony size. Our results suggest colony size correlates with measures of exploratory behavior and brain investment, with small-colony ants showing higher exploratory drive and faster exploration rate than the larger colony species, and greater relative investment in the primary olfactory brain region, the antennal lobe, than the larger colony species., (© 2019 S. Karger AG, Basel.)
- Published
- 2020
- Full Text
- View/download PDF
23. Brain evolution in social insects: advocating for the comparative approach.
- Author
-
Godfrey RK and Gronenberg W
- Subjects
- Animals, Brain growth & development, Insecta growth & development, Neural Pathways growth & development, Neuronal Plasticity, Organ Size, Species Specificity, Synaptic Transmission, Behavior, Animal, Biological Evolution, Brain physiology, Insecta physiology, Neural Pathways physiology, Social Behavior
- Abstract
Sociality is classified as one of the major transitions in the evolution of complexity and much effort has been dedicated to understanding what traits predispose lineages to sociality. Conversely, studies addressing the role of sociality in brain evolution (e.g., the social brain hypothesis) have not focused on particular traits and instead relied largely on measurements of relative brain composition. Hymenoptera range from solitary to advanced social species, providing enticing comparisons for studying sociality and neural trait evolution. Here we argue that measuring the role of sociality in brain evolution will benefit from attending to recent advances in neuroethology and adopting existing phylogenetic comparative methods employed in analysis of non-neural traits. Such analyses should rely on traits we expect to vary at the taxonomic level used in comparative analyses and include phylogenetic structure. We outline the limits of brain size and volumetric interpretation and advocate closer attention to trait stability and plasticity at different levels of organization. We propose neural traits measured at the cellular, circuit, and molecular levels will serve as more robust variables for evolutionary analyses. We include examples of particular traits and specific clades that are well-suited to answer questions about the role of sociality in nervous system evolution.
- Published
- 2019
- Full Text
- View/download PDF
24. Peripheral sensory organs vary among ant workers but variation does not predict division of labor.
- Author
-
Leitner N, Charbonneau D, Gronenberg W, and Dornhaus A
- Subjects
- Animals, Microscopy, Electron, Scanning, Neurons physiology, Ants physiology, Behavior, Animal physiology, Sensilla physiology
- Abstract
The neural mechanisms underlying behavioral variation among individuals are not well understood. Differences among individuals in sensory sensitivity could limit the environmental stimuli to which an individual is capable of responding and have, indeed, been shown to relate to behavioral differences in different species. Here, we show that ant workers in Temnothorax rugatulus differ considerably in the number of antennal sensory structures, or sensilla (by 45% in density and over 100% in estimated total number). A larger quantity of sensilla may reflect a larger quantity of underlying sensory neurons. This would increase the probability that a given set of neurons in the antenna detects an environmental stimulus and becomes excited, thereby eliciting the expression of a behavior downstream at lower stimulus levels than an individual with comparatively fewer sensilla. Individual differences in antennal sensilla density, however, did not predict worker activity level or performance of any task, suggesting either that variation in sensilla density does not, in fact, reflect variation in sensory sensitivity or that individual sensory response thresholds to task-associated stimuli do not determine task allocation as is commonly assumed, at least in this social insect. More broadly, our finding that even closely related individuals can differ strongly in peripheral sensory organ elaboration suggests that such variation in sensory organs could underlie other cases of intraspecific behavioral variation., (Copyright © 2018 Elsevier B.V. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
25. Performance, morphology and control of power-amplified mandibles in the trap-jaw ant Myrmoteras (Hymenoptera: Formicidae).
- Author
-
Larabee FJ, Gronenberg W, and Suarez AV
- Subjects
- Animals, Biological Evolution, Biomechanical Phenomena, Mandible anatomy & histology, Mandible physiology, Ants anatomy & histology, Ants physiology
- Abstract
Trap-jaw ants are characterized by high-speed mandibles used for prey capture and defense. Power-amplified mandibles have independently evolved at least four times among ants, with each lineage using different structures as a latch, spring and trigger. We examined two species from the genus Myrmoteras (subfamily Formicinae), whose morphology is unique among trap-jaw ant lineages, and describe the performance characteristics, spring-loading mechanism and neuronal control of Myrmoteras strikes. Like other trap-jaw ants, Myrmoteras latch their jaws open while the large closer muscle loads potential energy in a spring. The latch differs from other lineages and is likely formed by the co-contraction of the mandible opener and closer muscles. The cuticle of the posterior margin of the head serves as a spring, and is deformed by approximately 6% prior to a strike. The mandibles are likely unlatched by a subgroup of closer muscle fibers with particularly short sarcomeres. These fast fibers are controlled by two large motor neurons whose dendrites overlap with terminals of large sensory neurons originating from labral trigger hairs. Upon stimulation of the trigger hairs, the mandibles shut in as little as 0.5 ms and at peak velocities that are comparable with other trap-jaw ants, but with much slower acceleration. The estimated power output of the mandible strike (21 kW kg
-1 ) confirms that Myrmoteras jaws are indeed power amplified. However, the power output of Myrmoteras mandibles is significantly lower than distantly related trap-jaw ants using different spring-loading mechanisms, indicating a relationship between power-amplification mechanism and performance., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2017. Published by The Company of Biologists Ltd.)- Published
- 2017
- Full Text
- View/download PDF
26. Social complexity influences brain investment and neural operation costs in ants.
- Author
-
Kamhi JF, Gronenberg W, Robson SK, and Traniello JF
- Subjects
- Animals, Cognition, Electron Transport Complex IV physiology, Energy Metabolism, Mushroom Bodies physiology, Organ Size, Ants physiology, Brain physiology, Social Behavior
- Abstract
The metabolic expense of producing and operating neural tissue required for adaptive behaviour is considered a significant selective force in brain evolution. In primates, brain size correlates positively with group size, presumably owing to the greater cognitive demands of complex social relationships in large societies. Social complexity in eusocial insects is also associated with large groups, as well as collective intelligence and division of labour among sterile workers. However, superorganism phenotypes may lower cognitive demands on behaviourally specialized workers resulting in selection for decreased brain size and/or energetic costs of brain metabolism. To test this hypothesis, we compared brain investment patterns and cytochrome oxidase (COX) activity, a proxy for ATP usage, in two ant species contrasting in social organization. Socially complex Oecophylla smaragdina workers had larger brain size and relative investment in the mushroom bodies (MBs)-higher order sensory processing compartments-than the more socially basic Formica subsericea workers. Oecophylla smaragdina workers, however, had reduced COX activity in the MBs. Our results suggest that as in primates, ant group size is associated with large brain size. The elevated costs of investment in metabolically expensive brain tissue in the socially complex O. smaragdina, however, appear to be offset by decreased energetic costs., (© 2016 The Author(s).)
- Published
- 2016
- Full Text
- View/download PDF
27. Amblypygids: Model Organisms for the Study of Arthropod Navigation Mechanisms in Complex Environments?
- Author
-
Wiegmann DD, Hebets EA, Gronenberg W, Graving JM, and Bingman VP
- Abstract
Navigation is an ideal behavioral model for the study of sensory system integration and the neural substrates associated with complex behavior. For this broader purpose, however, it may be profitable to develop new model systems that are both tractable and sufficiently complex to ensure that information derived from a single sensory modality and path integration are inadequate to locate a goal. Here, we discuss some recent discoveries related to navigation by amblypygids, nocturnal arachnids that inhabit the tropics and sub-tropics. Nocturnal displacement experiments under the cover of a tropical rainforest reveal that these animals possess navigational abilities that are reminiscent, albeit on a smaller spatial scale, of true-navigating vertebrates. Specialized legs, called antenniform legs, which possess hundreds of olfactory and tactile sensory hairs, and vision appear to be involved. These animals also have enormous mushroom bodies, higher-order brain regions that, in insects, integrate contextual cues and may be involved in spatial memory. In amblypygids, the complexity of a nocturnal rainforest may impose navigational challenges that favor the integration of information derived from multimodal cues. Moreover, the movement of these animals is easily studied in the laboratory and putative neural integration sites of sensory information can be manipulated. Thus, amblypygids could serve as model organisms for the discovery of neural substrates associated with a unique and potentially sophisticated navigational capability. The diversity of habitats in which amblypygids are found also offers an opportunity for comparative studies of sensory integration and ecological selection pressures on navigation mechanisms.
- Published
- 2016
- Full Text
- View/download PDF
28. Specialization and group size: brain and behavioural correlates of colony size in ants lacking morphological castes.
- Author
-
Amador-Vargas S, Gronenberg W, Wcislo WT, and Mueller U
- Subjects
- Animals, Brain anatomy & histology, Panama, Social Behavior, Ants anatomy & histology, Ants physiology, Mushroom Bodies anatomy & histology
- Abstract
Group size in both multicellular organisms and animal societies can correlate with the degree of division of labour. For ants, the task specialization hypothesis (TSH) proposes that increased behavioural specialization enabled by larger group size corresponds to anatomical specialization of worker brains. Alternatively, the social brain hypothesis proposes that increased levels of social stimuli in larger colonies lead to enlarged brain regions in all workers, regardless of their task specialization. We tested these hypotheses in acacia ants (Pseudomyrmex spinicola), which exhibit behavioural but not morphological task specialization. In wild colonies, we marked, followed and tested ant workers involved in foraging tasks on the leaves (leaf-ants) and in defensive tasks on the host tree trunk (trunk-ants). Task specialization increased with colony size, especially in defensive tasks. The relationship between colony size and brain region volume was task-dependent, supporting the TSH. Specifically, as colony size increased, the relative size of regions within the mushroom bodies of the brain decreased in trunk-ants but increased in leaf-ants; those regions play important roles in learning and memory. Our findings suggest that workers specialized in defence may have reduced learning abilities relative to leaf-ants; these inferences remain to be tested. In societies with monomorphic workers, brain polymorphism enhanced by group size could be a mechanism by which division of labour is achieved., (© 2015 The Author(s) Published by the Royal Society. All rights reserved.)
- Published
- 2015
- Full Text
- View/download PDF
29. Molecular traces of alternative social organization in a termite genome.
- Author
-
Terrapon N, Li C, Robertson HM, Ji L, Meng X, Booth W, Chen Z, Childers CP, Glastad KM, Gokhale K, Gowin J, Gronenberg W, Hermansen RA, Hu H, Hunt BG, Huylmans AK, Khalil SM, Mitchell RD, Munoz-Torres MC, Mustard JA, Pan H, Reese JT, Scharf ME, Sun F, Vogel H, Xiao J, Yang W, Yang Z, Yang Z, Zhou J, Zhu J, Brent CS, Elsik CG, Goodisman MA, Liberles DA, Roe RM, Vargo EL, Vilcinskas A, Wang J, Bornberg-Bauer E, Korb J, Zhang G, and Liebig J
- Subjects
- Alternative Splicing, Animals, DNA Methylation, Epigenesis, Genetic, Gene Expression Profiling, Genome, Insect Proteins metabolism, Male, Fertility genetics, Gene Expression Regulation, Insect Proteins genetics, Isoptera genetics, Reproduction genetics, Social Behavior
- Abstract
Although eusociality evolved independently within several orders of insects, research into the molecular underpinnings of the transition towards social complexity has been confined primarily to Hymenoptera (for example, ants and bees). Here we sequence the genome and stage-specific transcriptomes of the dampwood termite Zootermopsis nevadensis (Blattodea) and compare them with similar data for eusocial Hymenoptera, to better identify commonalities and differences in achieving this significant transition. We show an expansion of genes related to male fertility, with upregulated gene expression in male reproductive individuals reflecting the profound differences in mating biology relative to the Hymenoptera. For several chemoreceptor families, we show divergent numbers of genes, which may correspond to the more claustral lifestyle of these termites. We also show similarities in the number and expression of genes related to caste determination mechanisms. Finally, patterns of DNA methylation and alternative splicing support a hypothesized epigenetic regulation of caste differentiation.
- Published
- 2014
- Full Text
- View/download PDF
30. Investment in higher order central processing regions is not constrained by brain size in social insects.
- Author
-
Muscedere ML, Gronenberg W, Moreau CS, and Traniello JF
- Subjects
- Animals, Ants anatomy & histology, Bees anatomy & histology, Body Size, Brain anatomy & histology, Brain physiology, Cognition, Organ Size, Wasps anatomy & histology, Ants physiology, Bees physiology, Biological Evolution, Wasps physiology
- Abstract
The extent to which size constrains the evolution of brain organization and the genesis of complex behaviour is a central, unanswered question in evolutionary neuroscience. Advanced cognition has long been linked to the expansion of specific brain compartments, such as the neocortex in vertebrates and the mushroom bodies in insects. Scaling constraints that limit the size of these brain regions in small animals may therefore be particularly significant to behavioural evolution. Recent findings from studies of paper wasps suggest miniaturization constrains the size of central sensory processing brain centres (mushroom body calyces) in favour of peripheral, sensory input centres (antennal and optic lobes). We tested the generality of this hypothesis in diverse eusocial hymenopteran species (ants, bees and wasps) exhibiting striking variation in body size and thus brain size. Combining multiple neuroanatomical datasets from these three taxa, we found no universal size constraint on brain organization within or among species. In fact, small-bodied ants with miniscule brains had mushroom body calyces proportionally as large as or larger than those of wasps and bees with brains orders of magnitude larger. Our comparative analyses suggest that brain organization in ants is shaped more by natural selection imposed by visual demands than intrinsic design limitations.
- Published
- 2014
- Full Text
- View/download PDF
31. Honeybees (Apis mellifera) learn to discriminate the smell of organic compounds from their respective deuterated isotopomers.
- Author
-
Gronenberg W, Raikhelkar A, Abshire E, Stevens J, Epstein E, Loyola K, Rauscher M, and Buchmann S
- Subjects
- Animals, Conditioning, Classical, Learning, Bees physiology, Odorants, Smell, Volatile Organic Compounds chemistry
- Abstract
The understanding of physiological and molecular processes underlying the sense of smell has made considerable progress during the past three decades, revealing the cascade of molecular steps that lead to the activation of olfactory receptor (OR) neurons. However, the mode of primary interaction of odorant molecules with the OR proteins within the sensory cells is still enigmatic. Two different concepts try to explain these interactions: the 'odotope hypothesis' suggests that OR proteins recognize structural aspects of the odorant molecule, whereas the 'vibration hypothesis' proposes that intra-molecular vibrations are the basis for the recognition of the odorant by the receptor protein. The vibration hypothesis predicts that OR proteins should be able to discriminate compounds containing deuterium from their common counterparts which contain hydrogen instead of deuterium. This study tests this prediction in honeybees (Apis mellifera) using the proboscis extension reflex learning in a differential conditioning paradigm. Rewarding one odour (e.g. a deuterated compound) with sucrose and not rewarding the respective analogue (e.g. hydrogen-based odorant) shows that honeybees readily learn to discriminate hydrogen-based odorants from their deuterated counterparts and supports the idea that intra-molecular vibrations may contribute to odour discrimination.
- Published
- 2014
- Full Text
- View/download PDF
32. Division of labor and structural plasticity in an extrinsic serotonergic mushroom body neuron in the ant Pheidole dentata.
- Author
-
Giraldo YM, Patel E, Gronenberg W, and Traniello JF
- Subjects
- Animals, Ants physiology, Behavior, Animal, Mushroom Bodies physiology, Serotonergic Neurons physiology, Social Behavior, Ants cytology, Mushroom Bodies cytology, Serotonergic Neurons cytology
- Abstract
Worker polyphenisms in ants enable insightful analyses of neuronal underpinnings of division of labor, a crucial aspect of animal social organization. In the ant Pheidole dentata, which has a dimorphic worker caste, serotonin titer increases in the brain with age, modulating pheromonal recruitment communication and foraging, behaviors characteristic of mature individuals. Serotonin-immunoreactive (5HT-IR) neurons are found in the mushroom bodies (MB) and may modulate multi-sensory information processing associated with cues and social signals guiding task performance. The volume of this neuropil correlates with worker subcaste and age in P. dentata, but the role of structural variation in individual extrinsic MB neurons in division of labor in ants is poorly understood. We tested the hypothesis that branching complexity in a 5HT-IR calyx input neuron (CIN) in the MBs increases with age in minor workers of P. dentata in association with task repertoire expansion. We further predicted that major workers, which are defense specialists, have less elaborate CIN axonal arbors at any age in comparison to minor workers, which are task generalists. Contrary to our predictions, immunohistochemical and morphometric analyses revealed significantly greater CIN branching in both newly eclosed and mature major workers, and identified an effect of worker age on branching complexity only in majors. Our results indicate a modulatory role of the CIN in subcaste-specific behaviors and suggest behavioral specialization may be associated with the elaboration of specific MB neurons., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
33. Chromatic processing in the anterior optic tubercle of the honey bee brain.
- Author
-
Mota T, Gronenberg W, Giurfa M, and Sandoz JC
- Subjects
- Animals, Calcium metabolism, Color, Color Perception physiology, Evoked Potentials, Visual physiology, Photic Stimulation, Visual Pathways physiology, Bees physiology, Neurons physiology, Optic Lobe, Nonmammalian physiology, Visual Perception physiology
- Abstract
Color vision in honey bees (Apis mellifera) has been extensively studied at the behavioral level and, to a lesser degree, at the physiological level by means of electrophysiological intracellular recordings of single neurons. Few visual neurons have been so far characterized in the lateral protocerebrum of bees. Therefore, the possible implication of this region in chromatic processing remains unknown. We performed in vivo calcium imaging of interneurons in the anterior optic tubercle (AOTu) of honey bees upon visual stimulation of the compound eye to analyze chromatic response properties. Stimulation with distinct monochromatic lights (ultraviolet [UV], blue, and green) matching the sensitivity of the three photoreceptor types of the bee retina induced different signal amplitudes, temporal dynamics, and spatial activity patterns in the AOTu intertubercle network, thus revealing intricate chromatic processing properties. Green light strongly activated both the dorsal and ventral lobes of the AOTu's major unit; blue light activated the dorsal lobe more while UV light activated the ventral lobe more. Eye stimulation with mixtures of blue and green light induced suppression phenomena in which responses to the mixture were lower than those to the color components, thus concurring with color-opponent processing. These data provide evidence for a spatial segregation of color processing in the AOTu, which may serve for navigation purposes.
- Published
- 2013
- Full Text
- View/download PDF
34. Plasticity of the worker bumblebee brain in relation to age and rearing environment.
- Author
-
Jones BM, Leonard AS, Papaj DR, and Gronenberg W
- Subjects
- Animals, Brain growth & development, Mushroom Bodies growth & development, Organ Size, Physical Stimulation, Smell, Vision, Ocular, Bees growth & development, Housing, Animal, Neuronal Plasticity
- Abstract
The environment experienced during development can dramatically affect the brain, with possible implications for sensory processing, learning, and memory. Although the effects of single sensory modalities on brain development have been repeatedly explored, the additive or interactive effects of multiple modalities have been less thoroughly investigated. We asked how experience with multisensory stimuli affected brain development in the bumblebee Bombus impatiens. First, to establish the timeline of brain development during early adulthood, we estimated regional brain volumes across a range of ages. We discovered significant age-related volume changes in nearly every region of the brain. Next, to determine whether these changes were dependent upon certain environmental stimuli, we manipulated the visual and olfactory stimuli available to newly emerged bumblebee workers in a factorial manner. Newly emerged bumblebees were maintained in the presence or absence of supplemental visual and/or olfactory stimuli for 7 days, after which the volumes of several brain regions were estimated. We found that the volumes of the mushroom body lobes and calyces were larger in the absence of visual stimuli. Additionally, visual deprivation was associated with the expression of larger antennal lobes, the primary olfactory processing regions of the brain. In contrast, exposure to plant-derived olfactory stimuli did not have a significant effect on brain region volumes. This study is the first to explore the separate and interactive effects of visual and olfactory stimuli on bee brain development. Assessing the timing and sensitivity of brain development is a first step toward understanding how different rearing environments differentially affect regional brain volumes in this species. Our findings suggest that environmental factors experienced during the first week of adulthood can modify bumblebee brain development in many subtle ways., (© 2013 S. Karger AG, Basel.)
- Published
- 2013
- Full Text
- View/download PDF
35. Decision-making and associative color learning in harnessed bumblebees (Bombus impatiens).
- Author
-
Riveros AJ and Gronenberg W
- Subjects
- Animals, Bees, Decision Making, Models, Animal, Association Learning, Color Perception
- Abstract
In honeybees, the conditioning of the proboscis extension response (PER) has provided a powerful tool to explore the mechanisms underlying olfactory learning and memory. Unfortunately, PER conditioning does not work well for visual stimuli in intact honeybees, and performance is improved only after antennal amputation, thus limiting the analysis of visual learning and multimodal integration. Here, we study visual learning using the PER protocol in harnessed bumblebees, which exhibit high levels of odor learning under restrained conditions. We trained bumblebees in a differential task in which two colors differed in their rewarding values. We recorded learning performance as well as response latency and accuracy. Bumblebees rapidly learned the task and discriminated the colors within the first two trials. However, performance varied between combinations of colors and was higher when blue or violet was associated with a high reward. Overall, accuracy and speed were negatively associated, but both components increased during acquisition. We conclude that PER conditioning is a good tool to study visual learning, using Bombus impatiens as a model, opening new possibilities to analyze the proximate mechanisms of visual learning and memory, as well as the process of multimodal integration and decision-making.
- Published
- 2012
- Full Text
- View/download PDF
36. Coming of age in an ant colony: cephalic muscle maturation accompanies behavioral development in Pheidole dentata.
- Author
-
Muscedere ML, Traniello JF, and Gronenberg W
- Subjects
- Aging, Animals, Ants growth & development, Ants metabolism, Body Fat Distribution, Muscles anatomy & histology, Muscles physiology, Ants physiology, Behavior, Animal
- Abstract
Although several neurobiological and genetic correlates of aging and behavioral development have been identified in social insect workers, little is known about how other age-related physiological processes, such as muscle maturation, contribute to task performance. We examined post-eclosion growth of three major muscles of the head capsule in major and minor workers of the ant Pheidole dentata using workers of different ages with distinct task repertoires. Mandible closer muscle fibers, which provide bite force and are thus critical for the use of the mandibles for biting and load carrying, fill the posterio-lateral portions of the head capsule in mature, older workers of both subcastes. Mandible closer fibers of newly eclosed workers, in contrast, are significantly thinner in both subcastes and grow during at least the next 6 days in minor workers, suggesting this muscle has reduced functionality for a substantial period of adult life and thus constrains task performance capability. Fibers of the antennal muscles and the pharynx dilator, which control antennal movements and food intake, respectively, also increase significantly in thickness with age. However, these fibers are only slightly thinner in newly eclosed workers and attain their maximum thickness over a shorter time span in minors. The different growth rates of these functionally distinct muscles likely have consequences for how adult P. dentata workers, particularly minors, develop their full and diverse task repertoire as they age. Workers may be capable of feeding and interacting socially soon after eclosion, but require a longer period of development to effectively use their mandibles, which enable the efficient performance of tasks ranging from nursing to foraging and defense.
- Published
- 2011
- Full Text
- View/download PDF
37. Neural organization and visual processing in the anterior optic tubercle of the honeybee brain.
- Author
-
Mota T, Yamagata N, Giurfa M, Gronenberg W, and Sandoz JC
- Subjects
- Animals, Bees anatomy & histology, Brain anatomy & histology, Female, Nerve Net anatomy & histology, Photic Stimulation methods, Visual Fields physiology, Visual Pathways anatomy & histology, Bees physiology, Brain physiology, Evoked Potentials, Visual physiology, Nerve Net physiology, Neurons physiology, Visual Pathways physiology
- Abstract
The honeybee Apis mellifera represents a valuable model for studying the neural segregation and integration of visual information. Vision in honeybees has been extensively studied at the behavioral level and, to a lesser degree, at the physiological level using intracellular electrophysiological recordings of single neurons. However, our knowledge of visual processing in honeybees is still limited by the lack of functional studies of visual processing at the circuit level. Here we contribute to filling this gap by providing a neuroanatomical and neurophysiological characterization at the circuit level of a practically unstudied visual area of the bee brain, the anterior optic tubercle (AOTu). First, we analyzed the internal organization and neuronal connections of the AOTu. Second, we established a novel protocol for performing optophysiological recordings of visual circuit activity in the honeybee brain and studied the responses of AOTu interneurons during stimulation of distinct eye regions. Our neuroanatomical data show an intricate compartmentalization and connectivity of the AOTu, revealing a dorsoventral segregation of the visual input to the AOTu. Light stimuli presented in different parts of the visual field (dorsal, lateral, or ventral) induce distinct patterns of activation in AOTu output interneurons, retaining to some extent the dorsoventral input segregation revealed by our neuroanatomical data. In particular, activity patterns evoked by dorsal and ventral eye stimulation are clearly segregated into distinct AOTu subunits. Our results therefore suggest an involvement of the AOTu in the processing of dorsoventrally segregated visual information in the honeybee brain.
- Published
- 2011
- Full Text
- View/download PDF
38. Draft genome of the red harvester ant Pogonomyrmex barbatus.
- Author
-
Smith CR, Smith CD, Robertson HM, Helmkampf M, Zimin A, Yandell M, Holt C, Hu H, Abouheif E, Benton R, Cash E, Croset V, Currie CR, Elhaik E, Elsik CG, Favé MJ, Fernandes V, Gibson JD, Graur D, Gronenberg W, Grubbs KJ, Hagen DE, Viniegra AS, Johnson BR, Johnson RM, Khila A, Kim JW, Mathis KA, Munoz-Torres MC, Murphy MC, Mustard JA, Nakamura R, Niehuis O, Nigam S, Overson RP, Placek JE, Rajakumar R, Reese JT, Suen G, Tao S, Torres CW, Tsutsui ND, Viljakainen L, Wolschin F, and Gadau J
- Subjects
- Animals, Ants physiology, Base Sequence, Desert Climate, Hierarchy, Social, Molecular Sequence Data, North America, Phenotype, Polymorphism, Single Nucleotide genetics, Receptors, Odorant genetics, Sequence Analysis, DNA, Ants genetics, Gene Regulatory Networks genetics, Genome, Insect genetics, Genomics methods, Phylogeny
- Abstract
We report the draft genome sequence of the red harvester ant, Pogonomyrmex barbatus. The genome was sequenced using 454 pyrosequencing, and the current assembly and annotation were completed in less than 1 y. Analyses of conserved gene groups (more than 1,200 manually annotated genes to date) suggest a high-quality assembly and annotation comparable to recently sequenced insect genomes using Sanger sequencing. The red harvester ant is a model for studying reproductive division of labor, phenotypic plasticity, and sociogenomics. Although the genome of P. barbatus is similar to other sequenced hymenopterans (Apis mellifera and Nasonia vitripennis) in GC content and compositional organization, and possesses a complete CpG methylation toolkit, its predicted genomic CpG content differs markedly from the other hymenopterans. Gene networks involved in generating key differences between the queen and worker castes (e.g., wings and ovaries) show signatures of increased methylation and suggest that ants and bees may have independently co-opted the same gene regulatory mechanisms for reproductive division of labor. Gene family expansions (e.g., 344 functional odorant receptors) and pseudogene accumulation in chemoreception and P450 genes compared with A. mellifera and N. vitripennis are consistent with major life-history changes during the adaptive radiation of Pogonomyrmex spp., perhaps in parallel with the development of the North American deserts.
- Published
- 2011
- Full Text
- View/download PDF
39. Brain composition and olfactory learning in honey bees.
- Author
-
Gronenberg W and Couvillon MJ
- Subjects
- Animals, Bees, Brain anatomy & histology, Learning physiology, Smell physiology
- Abstract
Correlations between brain or brain component size and behavioral measures are frequently studied by comparing different animal species, which sometimes introduces variables that complicate interpretation in terms of brain function. Here, we have analyzed the brain composition of honey bees (Apis mellifera) that have been individually tested in an olfactory learning paradigm. We found that the total brain size correlated with the bees' learning performance. Among different brain components, only the mushroom body, a structure known to be involved in learning and memory, showed a positive correlation with learning performance. In contrast, visual neuropils were relatively smaller in bees that performed better in the olfactory learning task, suggesting modality-specific behavioral specialization of individual bees. This idea is also supported by inter-individual differences in brain composition. Some slight yet statistically significant differences in the brain composition of European and Africanized honey bees are reported. Larger bees had larger brains, and by comparing brains of different sizes, we report isometric correlations for all brain components except for a small structure, the central body., (2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
40. Africanized honeybees are slower learners than their European counterparts.
- Author
-
Couvillon MJ, DeGrandi-Hoffman G, and Gronenberg W
- Subjects
- Africa, Animals, Association Learning, Bees anatomy & histology, Cognition, Ecosystem, Europe, Feeding Behavior, Odorants, Reflex physiology, Reward, Social Behavior, Bees physiology, Learning physiology
- Abstract
Does cognitive ability always correlate with a positive fitness consequence? Previous research in both vertebrates and invertebrates provides mixed results. Here, we compare the learning and memory abilities of Africanized honeybees (Apis mellifera scutellata hybrid) and European honeybees (Apis mellifera ligustica). The range of the Africanized honeybee continues to expand, superseding the European honeybee, which led us to hypothesize that they might possess greater cognitive capabilities as revealed by a classical conditioning assay. Surprisingly, we found that fewer Africanized honeybees learn to associate an odor with a reward. Additionally, fewer Africanized honeybees remembered the association a day later. While Africanized honeybees are replacing European honeybees, our results show that they do so despite displaying a relatively poorer performance on an associative learning paradigm.
- Published
- 2010
- Full Text
- View/download PDF
41. Brain allometry and neural plasticity in the bumblebee Bombus occidentalis.
- Author
-
Riveros AJ and Gronenberg W
- Subjects
- Aging, Animals, Appetitive Behavior physiology, Body Size, Brain anatomy & histology, Brain physiology, Organ Size, Random Allocation, Bees anatomy & histology, Bees physiology, Neuronal Plasticity
- Abstract
Brain plasticity is a common phenomenon across animals and in many cases it is associated with behavioral transitions. In social insects, such as bees, wasps and ants, plasticity in a particular brain compartment involved in multisensory integration (the mushroom body) has been associated with transitions between tasks differing in cognitive demands. However, in most of these cases, transitions between tasks are age-related, requiring the experimental manipulation of the age structure in the studied colonies to distinguish age and experience-dependent effects. To better understand the interplay between brain plasticity and behavioral performance it would therefore be advantageous to study species whose division of labor is not age-dependent. Here, we focus on brain plasticity in the bumblebee Bombus occidentalis, in which division of labor is strongly affected by the individual's body size instead of age. We show that, like in vertebrates, body size strongly correlates with brain size. We also show that foraging experience, but not age, significantly correlates with the increase in the size of the mushroom body, and in particular one of its components, the medial calyx. Our results support previous findings from other social insects suggesting that the mushroom body plays a key role in experience-based decision making. We also discuss the use of bumblebees as models to analyze neural plasticity and the association between brain size and behavioral performance., (Copyright 2010 S. Karger AG, Basel.)
- Published
- 2010
- Full Text
- View/download PDF
42. Learning from learning and memory in bumblebees.
- Author
-
Riveros AJ and Gronenberg W
- Abstract
The difficulty to simultaneously record neural activity and behavior presents a considerable limitation for studying mechanisms of insect learning and memory. The challenge is finding a model suitable for the use of behavioral paradigms under the restrained conditions necessary for neural recording. In honeybees, Pavlovian conditioning relying on the proboscis extension reflex (PER) has been used with great success to study different aspects of insect cognition. However, it is desirable to combine the advantages of the PER with a more robust model that allows simultaneous electrical or optical recording of neural activity. Here, we briefly discuss the potential use of bumblebees as models for the study of learning and memory under restrained conditions. We base our arguments on the well-known cognitive abilities of bumblebees, their social organization and phylogenetic proximity to honeybees, our recent success using Pavlovian conditioning to study learning in two bumblebee species, and on the recently demonstrated robustness of bumblebees under conditions suitable for electrophysiological recording.
- Published
- 2009
- Full Text
- View/download PDF
43. Visual processing in the central bee brain.
- Author
-
Paulk AC, Dacks AM, Phillips-Portillo J, Fellous JM, and Gronenberg W
- Subjects
- Action Potentials, Animals, Bees anatomy & histology, Brain anatomy & histology, Brain physiology, Color, Evoked Potentials, Visual, Medulla Oblongata anatomy & histology, Medulla Oblongata physiology, Membrane Potentials, Microelectrodes, Motion, Neurons cytology, Photic Stimulation, Time Factors, Visual Pathways anatomy & histology, Visual Pathways physiology, Bees physiology, Neurons physiology, Visual Perception physiology
- Abstract
Visual scenes comprise enormous amounts of information from which nervous systems extract behaviorally relevant cues. In most model systems, little is known about the transformation of visual information as it occurs along visual pathways. We examined how visual information is transformed physiologically as it is communicated from the eye to higher-order brain centers using bumblebees, which are known for their visual capabilities. We recorded intracellularly in vivo from 30 neurons in the central bumblebee brain (the lateral protocerebrum) and compared these neurons to 132 neurons from more distal areas along the visual pathway, namely the medulla and the lobula. In these three brain regions (medulla, lobula, and central brain), we examined correlations between the neurons' branching patterns and their responses primarily to color, but also to motion stimuli. Visual neurons projecting to the anterior central brain were generally color sensitive, while neurons projecting to the posterior central brain were predominantly motion sensitive. The temporal response properties differed significantly between these areas, with an increase in spike time precision across trials and a decrease in average reliable spiking as visual information processing progressed from the periphery to the central brain. These data suggest that neurons along the visual pathway to the central brain not only are segregated with regard to the physical features of the stimuli (e.g., color and motion), but also differ in the way they encode stimuli, possibly to allow for efficient parallel processing to occur.
- Published
- 2009
- Full Text
- View/download PDF
44. Olfactory learning and memory in the bumblebee Bombus occidentalis.
- Author
-
Riveros AJ and Gronenberg W
- Subjects
- Animals, Conditioning, Operant, Disease Models, Animal, Feeding Behavior physiology, Female, Motor Activity physiology, Pupa physiology, Reflex physiology, Satiety Response, Sucrose metabolism, Bees physiology, Learning physiology, Memory physiology, Smell physiology
- Abstract
In many respects, the behavior of bumblebees is similar to that of the closely related honeybees, a long-standing model system for learning and memory research. Living in smaller and less regulated colonies, bumblebees are physiologically more robust and thus have advantages in particular for indoor experiments. Here, we report results on Pavlovian odor conditioning of bumblebees using the proboscis extension reflex (PER) that has been successfully used in honeybee learning research. We examine the effect of age, body size, and experience on learning and memory performance. We find that age does not affect learning and memory ability, while body size positively correlates with memory performance. Foraging experience seems not to be necessary for learning to occur, but it may contribute to learning performance as bumblebees with more foraging experience on average were better learners. The PER represents a reliable tool for learning and memory research in bumblebees and allows examining interspecific similarities and differences of honeybee and bumblebee behavior, which we discuss in the context of social organization.
- Published
- 2009
- Full Text
- View/download PDF
45. Color processing in the medulla of the bumblebee (Apidae: Bombus impatiens).
- Author
-
Paulk AC, Dacks AM, and Gronenberg W
- Subjects
- Animals, Electrophysiology, Histamine metabolism, Immunohistochemistry, Medulla Oblongata anatomy & histology, Medulla Oblongata cytology, Medulla Oblongata metabolism, Neurons metabolism, Optic Lobe, Nonmammalian anatomy & histology, Optic Lobe, Nonmammalian cytology, Optic Lobe, Nonmammalian metabolism, Photic Stimulation methods, Serotonin metabolism, Visual Pathways cytology, Visual Pathways physiology, gamma-Aminobutyric Acid metabolism, Bees, Color Perception physiology, Medulla Oblongata physiology, Membrane Potentials physiology, Neurons physiology, Optic Lobe, Nonmammalian physiology, Visual Pathways anatomy & histology, Visual Perception physiology
- Abstract
The mechanisms of processing a visual scene involve segregating features (such as color) into separate information channels at different stages within the brain, processing these features, and then integrating this information at higher levels in the brain. To examine how this process takes place in the insect brain, we focused on the medulla, an area within the optic lobe through which all of the visual information from the retina must pass before it proceeds to central brain areas. We used histological and immunocytochemical techniques to examine the bumblebee medulla and found that the medulla is divided into eight layers. We then recorded and morphologically identified 27 neurons with processes in the medulla. During our recordings we presented color cues to determine whether response types correlated with locations of the neural branching patterns of the filled neurons among the medulla layers. Neurons in the outer medulla layers had less complex color responses compared to neurons in the inner medulla layers and there were differences in the temporal dynamics of the responses among the layers. Progressing from the outer to the inner medulla, neurons in the different layers appear to process increasingly complex aspects of the natural visual scene., ((c) 2009 Wiley-Liss, Inc.)
- Published
- 2009
- Full Text
- View/download PDF
46. Brain size: a global or induced cost of learning?
- Author
-
Snell-Rood EC, Papaj DR, and Gronenberg W
- Subjects
- Animals, Biological Evolution, Brain physiology, Butterflies physiology, Feeding Behavior physiology, Hypertrophy, Mushroom Bodies anatomy & histology, Mushroom Bodies physiology, Organ Size physiology, Smell physiology, Species Specificity, Adaptation, Physiological physiology, Behavior, Animal physiology, Brain anatomy & histology, Butterflies anatomy & histology, Learning physiology
- Abstract
The role of brain size as a cost of learning remains enigmatic; the nature and timing of such costs is particularly uncertain. On one hand, comparative studies suggest that congenitally large brains promote better learning and memory. In that case, brain size exacts a global cost that accrues even if learning does not take place; on the other hand, some developmental studies suggest that brains grow with experience, indicating a cost that is induced when learning occurs. The issue of how costs are incurred is an important one, because global costs are expected to constrain the evolution of learning more than would induced costs. We tested whether brain size represented a global and/or an induced cost of learning in the cabbage white butterfly, Pieris rapae. We assayed the ability of full sibling families to learn to locate either green hosts, for which butterflies have an innate search bias, or red hosts, which are more difficult to learn to locate. Naïve butterflies were sacrificed at emergence and congenital brain volume estimated as a measure of global costs; experienced butterflies were sacrificed after learning and change in brain volume estimated as a measure of induced costs. Only for the mushroom body, a brain region involved in learning and memory in other insects, was volume at emergence related to learning or host-finding. Butterfly families that emerged with relatively larger mushroom bodies showed a greater tendency to improve their ability to find red hosts across the two days of host-search. The volume of most brain regions increased with time in a manner suggesting host experience itself was important: first, total number of landings during host-search was positively related to mushroom body calyx volume, and, second, experience with the red host was positively related to mushroom body lobe volume. At the family level, the relative volume of the mushroom body calyx and antennal lobes following learning was positively related to overall success in finding red hosts. Overall, our results suggest that within species, brain size might act as a small global cost of learning, but that environment-specific changes in brain size might reduce the overall costs of neural tissue in the evolution of learning., ((c) 2009 S. Karger AG, Basel.)
- Published
- 2009
- Full Text
- View/download PDF
47. Higher order visual input to the mushroom bodies in the bee, Bombus impatiens.
- Author
-
Paulk AC and Gronenberg W
- Subjects
- Action Potentials, Animals, Brain anatomy & histology, Brain physiology, Brain Mapping, Color Perception physiology, Habituation, Psychophysiologic, Motion Perception, Mushroom Bodies anatomy & histology, Neurons, Afferent physiology, Optic Lobe, Nonmammalian anatomy & histology, Optic Lobe, Nonmammalian physiology, Photic Stimulation, Signal Transduction, Bees physiology, Mushroom Bodies physiology, Visual Perception physiology
- Abstract
To produce appropriate behaviors based on biologically relevant associations, sensory pathways conveying different modalities are integrated by higher-order central brain structures, such as insect mushroom bodies. To address this function of sensory integration, we characterized the structure and response of optic lobe (OL) neurons projecting to the calyces of the mushroom bodies in bees. Bees are well known for their visual learning and memory capabilities and their brains possess major direct visual input from the optic lobes to the mushroom bodies. To functionally characterize these visual inputs to the mushroom bodies, we recorded intracellularly from neurons in bumblebees (Apidae: Bombus impatiens) and a single neuron in a honeybee (Apidae: Apis mellifera) while presenting color and motion stimuli. All of the mushroom body input neurons were color sensitive while a subset was motion sensitive. Additionally, most of the mushroom body input neurons would respond to the first, but not to subsequent, presentations of repeated stimuli. In general, the medulla or lobula neurons projecting to the calyx signaled specific chromatic, temporal, and motion features of the visual world to the mushroom bodies, which included sensory information required for the biologically relevant associations bees form during foraging tasks.
- Published
- 2008
- Full Text
- View/download PDF
48. Correlation between facial pattern recognition and brain composition in paper wasps.
- Author
-
Gronenberg W, Ash LE, and Tibbetts EA
- Subjects
- Animals, Behavior, Animal physiology, Brain Mapping, Wasps anatomy & histology, Brain anatomy & histology, Face, Pattern Recognition, Visual, Recognition, Psychology, Wasps physiology
- Abstract
Unique among insects, some paper wasp species recognize conspecific facial patterns during social communication. To evaluate whether specialized brain structures are involved in this task, we measured brain and brain component size in four different paper wasp species, two of which show facial pattern recognition. These behavioral abilities were not reflected by an increase in brain size or an increase in the size of the primary visual centers (medulla, lobula). Instead, wasps showing face recognition abilities had smaller olfactory centers (antennal lobes). Although no single brain compartment explains the wasps' specialized visual abilities, multi-factorial analysis of the different brain components, particularly the antennal lobe and the mushroom body sub-compartments, clearly separates those species that show facial pattern recognition from those that do not. Thus, there appears to be some neural specialization for visual communication in Polistes. However, the apparent lack of optic lobe specialization suggests that the visual processing capabilities of paper wasps might be preadapted for pattern discrimination and the ability to discriminate facial markings could require relatively small changes in their neuronal substrate., ((c) 2007 S. Karger AG, Basel.)
- Published
- 2008
- Full Text
- View/download PDF
49. Electrical potentials indicate stimulus expectancy in the brains of ants and bees.
- Author
-
Ramón F and Gronenberg W
- Subjects
- Animals, Biological Evolution, Electroretinography, Ganglia, Invertebrate physiology, Photic Stimulation, Photoreceptor Cells, Invertebrate physiology, Visual Pathways physiology, Ants physiology, Bees physiology, Brain physiology, Evoked Potentials, Visual physiology
- Abstract
In vertebrates, and in humans in particular, so-called 'omitted stimulus potentials' can be electrically recorded from the brain or scalp upon repeated stimulation with simple stimuli such as light flashes. While standard evoked potentials follow each stimulus in a series, 'omitted stimulus potentials' occur when an additional stimulus is expected after the end of a stimulus series. These potentials represent neuronal plasticity and are assumed to be involved in basic cognitive processes. We recorded electroretinograms from the eyes and visually evoked potentials from central brain areas of honey bees and ants, social insects to which cognitive abilities have been ascribed and whose rich-behavioral repertoires include navigation, learning and memory. We demonstrate that omitted stimulus potentials occur in these insects. Omitted stimulus potentials in bees and ants show similar temporal characteristics to those found in crayfish and vertebrates, suggesting that common mechanisms may underlie this form of short-term neuronal plasticity.
- Published
- 2005
- Full Text
- View/download PDF
50. Brain allometry in bumblebee and honey bee workers.
- Author
-
Mares S, Ash L, and Gronenberg W
- Subjects
- Animals, Body Weight physiology, Brain anatomy & histology, Brain Chemistry, Organ Size physiology, Species Specificity, Bees physiology, Brain physiology, Social Behavior
- Abstract
Within a particular animal taxon, larger bodied species generally have larger brains. Increased brain size usually correlates with increased behavioral repertoires and often with superior cognitive abilities. Bumblebees are eusocial insects that show pronounced size polymorphism among workers, whereas in honey bees size variation is much less pronounced. Recent studies suggest that within a given colony, large bumblebee workers are more efficient foragers and are better learners than their smaller sisters. Here we examine the allometric relationship between brain and body size of worker bumblebees and honey bees. We find that larger bees have larger brains and that most brain components show a similar size increase as the overall brain. One particular brain structure, the central body, is relatively smaller in large bumblebees compared to small bees. The same is true for the mushroom body lobes, whereas the mushroom body calyces, which receive sensory input, are not reduced in larger bumblebees or honey bees. Honey bees have relatively smaller brains, as well as smaller mushroom bodies, than bumblebee workers. We discuss why brain or mushroom body size does not necessarily correlate with the degree of a species' social organization., (Copyright 2005 S. Karger AG, Basel.)
- Published
- 2005
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.