@phdthesis{Blatt2001,
  author    = {Blatt, Jasmina},
  title     = {Haemolymph sugar homeostasis and the control of the proventriculus in the honeybee (Apis mellifera carnica L.)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-880},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2001},
  abstract  = {The proventriculus regulates the food passage from crop to midgut. As the haemolymph provides a constantly updated indication of an insect's nutritional state, it is assumed that the factor controlling the proventri-culus activity is to be found in the haemolymph. The purpose of this doctoral thesis was to investigate how output (metabolic rate), input (food quality and food quantity) and internal state variables (haemolymph osmolarity and haemolymph sugar titer) affect each other and which of these factors controls the activity of the proventriculus in the honeybee. Therefore free-flying foragers were trained to collect con-trolled amounts of different sugar solutions. Immediately after feeding, metabolic rates were measured over different periods of time, then crop-emptying rates and haemolymph sugar titers were measured for the same individual bees. Under all investigated conditions, both the sugar transport rates through the proventriculus and the haemolyph sugar titers depended mainly on the metabolism. For bees collecting controlled amounts of 15 per cent, 30 per cent or 50 per cent sucrose solution haemolymph trehalose, glucose and fructose titers were constant for metabolic rates from 0 to 4.5 mlCO2/h. At higher metabolic rates, trehalose concentration decreased while that of glucose and fructose increased with the exception of bees fed 15 per cent sucrose solution. As the supply of sugar from the crop via the proventriculus was sufficient to support even the highest metabolic rates, the observed pattern must result from an upper limit in the capacity of the fat body to synthesise trehalose. The maximal rate of conversion of glucose to trehalose in the fat body was therefore calculated to average 92.4 µg glucose/min. However, for bees fed 15 per cent sucrose solution both the rate of conversion of glucose to trehalose and the rate of sugar transport from the crop to the midgut were limited, causing an overall decrease in total haemolymph sugar titers for metabolic rates higher than 5 mlCO2/h. Haemolymph sucrose titers were generally low but increased with increasing metabolic rates, even though sucrose was not always detected in bees with high metabolic rates. Though foragers were able to adjust their sugar transport rates precisely to their metabolic rates, a fixed surplus of sugars was transported through the proventriculus under specific feed-ing conditions. This fixed amount of sugars increased with increasing concentration and in-creasing quantity of fed sugar solution, but decreased with progressing time after feeding. This fixed amount of sugars was independent of the metabolic rates of the bees and of the molarity and viscosity of the fed sugar solution. As long as the bees did not exhaust their crop content, the haemolymph sugar titers were unaffected by the sugar surplus, by the time after feeding, by the concentration and by the viscosity of fed sugar solution. When bees were fed pure glucose (or fructose) solutions, un-usually little fructose (or glucose) was found in the haemolymph, leading to lower total haemolymph sugar titers, while the trehalose titer remained unaffected. In order to investigate the mechanisms underlying the regulation of the honeybee proven-triculus, foraging bees were injected either with metabolisable (glucose, fructose, trehalose), or non-metabolisable sugars (sorbose). Bees reacted to injections of metabolisable sugars with reduced crop-emptying rates, but injection of non-metabolisable sugars had no influence on crop emptying. Therefore it is concluded that the proventriculus regulation is controlled by the concentration of metabolisable compounds in the haemolymph, and not by the haemo-lymph osmolarity. A period of 10min was enough to observe reduced crop emptying rates after injections. It is suggested that glucose and fructose have an effect on the proventriculus activity only via their transformation to trehalose. However, when the bees were already in-jected 5min after feeding, no response was detectable. In addition it was investigated whether the overregulation is the result of feed-forward regulation for the imminent take-off and flight. In a first experiment, we investigated whether the bees release an extra amount of sugar solution very shortly before leaving for the hive. In a second experiment, it was tested whether the distance covered by the bees might have an influence on the surplus amount released prior to the take-off. In a third experiment, it was investigated if walking bees fail to release this extra amount of sugars, as they do not have to fly. Though we were not able to demonstrate that the overregulation is the result of feed-forward regulation for the imminent take-off and flight, it is conceivable that this phenome-non is a fixed reaction in foragers that can not be modulated. To investigate whether regulated haemolymph sugar titers are also observed in honeybee foragers returning from natural food sources, their crop contents and haemolymph sugar titers were investigated. While the quantity of the collected nectar was without influence on the haemolymph sugar titers, foragers showed increasing haemolymph sugar titers of glucose, fructose and sucrose with increasing sugar concentration of the carried nectar. In contrast no relationship between crop nectar concentrations and haemolymph trehalose titers was observed. We are sure that the regulation of food passage from crop to midgut is controlled by the trehalose titer. However, under some conditions the balance between consumption and income is not numerically exact. This imprecision depends on the factors which have an impact on the foraging energetics of the bees but are independent of those without influence on the foraging energetics. Therefore we would assume that the proventriculus activity is modulated by the motivational state of the bees.},
  subject      = {Biene},
  language  = {en}
}
@phdthesis{Thom2002,
  author    = {Thom, Corinna},
  title     = {Dynamics and Communication Structures of Nectar Foraging in Honey Bees (Apis mellifera)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-3601},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2002},
  abstract  = {In this thesis, I examined honey bee nectar foraging with emphasis on the communication system. To document how a honey bee colony adjusts its daily nectar foraging effort, I observed a random sample of individually marked workers during the entire day, and then estimated the number and activity of all nectar foragers in the colony. The total number of active nectar foragers in a colony changed frequently between days. Foraging activity did not usually change between days. A honey bee colony adjusts its daily foraging effort by changing the number of its nectar foragers rather than their activity. I tested whether volatiles produced by a foraging colony activated nectar foragers of a non-foraging colony by connecting with a glass tube two colonies. Each colony had access to a different green house. In 50\% of all experiments, volatile substances from the foraging colony stimulated nectar foragers of the non-foraging colony to fly to an empty feeder. The results of this study show that honey bees can produce a chemical signal or cue that activates nectar foragers. However, more experiments are needed to establish the significance of the activating volatiles for the foraging communication system. The brief piping signal of nectar foragers inhibits forager recruitment by stopping waggle dances (Nieh 1993, Kirchner 1993). However, I observed that many piping signals (approximately 43\%) were produced off the dance floor, a restricted area in the hive where most waggle dances are performed. If the inhibition of waggle dances would be the only function of the brief piping signal, tremble dancers should produce piping signals mainly on the dance floor, where the probability to encounter waggle dancers is highest. To therefore investigate the piping signal in more detail, I experimentally established the foraging context of the brief piping signal, characterized its acoustic properties, and documented for the first time the unique behavior of piping nectar foragers by observing foragers throughout their entire stay in the hive. Piping nectar foragers usually began to tremble dance immediately upon their return into the hive, spent more time in the hive, more time dancing, had longer unloading latencies, and were the only foragers that sometimes unloaded their nectar directly into cells instead of giving it to a nectar receiver bee. Most of the brief piping signals (approximately 99\%) were produced by tremble dancers, yet not all tremble dancers (approximately 48\%) piped. This suggests that piping and tremble dancing have related, but not identical functions in the foraging system. Thus, the brief piping signals may not only inhibit forager recruitment, but have an additional function both on and off the dance floor. In particular, the piping signal might function 1. to stop the recruitment of additional nectar foragers, and 2. as a modulatory signal to alter the response threshold of signal receivers to the tremble dance. The observation that piping tremble dancers often did not experience long unloading delays before they started to dance gave rise to a question. A forager's unloading delay provides reliable information about the relative work capacities of nectar foragers and nectar receivers, because each returning forager unloads her nectar to a nectar receiver before she takes off for the next foraging trip. Queuing delays for either foragers or receivers lower foraging efficiency and can be eliminated by recruiting workers to the group in shortage. Short unloading delays indicate to the nectar forager a shortage of foragers and stimulate waggle dancing which recruits nectar foragers. Long unloading delays indicate a shortage of nectar receivers and stimulate tremble dancing which recruits nectar receivers (Seeley 1992, Seeley et al. 1996). Because the short unloading delays of piping tremble dancers indicated that tremble dancing can be elicited by other factors than long unloading delays, I tested whether a hive-external stimulus, the density of foragers at the food source, stimulated tremble dancing directly. The experiments show that tremble dancing can be caused directly by a high density of foragers at the food source and suggest that tremble dancing can be elicited by a decrease of foraging efficiency either inside (e.g. shortage of receiver bees) or outside (e.g. difficulty of loading nectar) the hive. Tremble dancing as a reaction to hive-external stimuli seems to occur under natural conditions and can thus be expected to have some adaptive significance. The results imply that if the hive-external factors that elicit tremble dancing do not indicate a shortage of nectar receiver bees in the hive, the function of the tremble dance may not be restricted to the recruitment of additional nectar receivers, but might be the inhibition or re-organization of nectar foraging.},
  subject      = {Bienen <Familie>},
  language  = {en}
}
@phdthesis{Groh2005,
  author    = {Groh, Claudia},
  title     = {Environmental influences on the development of the female honeybee brain Apis mellifera},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-17388},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2005},
  abstract  = {F{\"u}r die Honigbiene spielt der Geruchssinn eine entscheidende Rolle bei der Kommunikation innerhalb des Sozialstaates. Kastenspezifische, auf uweltbedingten Einfl{\"u}ssen basierende sowie altersbedingte Unterschiede im olfaktorisch gesteuerten Verhalten liefern ein hervorragendes Modellsystem f{\"u}r diese Studie, um die Entwicklung und Funktion neuronaler Plastizit{\"a}t im olfaktorischen System zu untersuchen. Diese Studie konzentriert sich auf Unterschiede zwischen K{\"o}niginnen und Arbeiterinnen, den beiden weiblichen Kasten innerhalb des Bienestaates, sowie auf umweltbedingte Plastizit{\"a}t. Diploide Eier, aus denen sich K{\"o}niginnen und Arbeiterinnen entwickeln, sind genetisch identisch. Dennoch entwickeln sich K{\"o}niginnen wesentlich schneller zum Adulttier als Arbeiterinnen, sind als Imago gr{\"o}ßer, leben wesentlich l{\"a}nger und zeigen andere Verhaltensweisen. Diese Unterschiede werden durch eine differentielle larvale F{\"u}tterung initiiert. Im Anschluss an das Larvenstadium und somit nach erfolgter Kastendetermination, entwickeln sich die Bienen {\"u}ber eine Puppenphase (verdeckelte Phase) zum Imago. Adulte Bienen klimatisieren das zentrale Brutareal auf einer mittleren Temperatur von 35°C konstant. Bienen, die bei niedrigeren Temperaturen innerhalb des physiologisch relevanten Bereichs aufwachsen, weisen Defizite im olfaktorischen Lernverhalten und in der Tanzkommunikation auf. M{\"o}gliche neuronale Korrelate f{\"u}r altersbedingte, temperatur- und kastenspezifische Unterschiede im olfaktorisch gesteuerten Verhalten sollten in dieser Arbeit betrachtet werden. Die strukturellen Analysen konzentrierten sich dabei auf prim{\"a}re (Antennalloben) und sekund{\"a}re (Pilzk{\"o}rper-Calyces)olfaktorische Verarbeitungszentren im Gehirn von sich entwickelnden und adulten Tieren beider Kasten. Synchron verdeckelte Brutzellen beider Kasten wurden unter kontrollierten Bedingungen im Inkubator herangezogen. Neuroanatomische Untersuchungen wurden an fixierten Gewebeschnitten mittels einer Doppelfluoreszenzf{\"a}rbung mit Fluor-Phalloidin und anti-Synapsin Immuncytochemie durchgef{\"u}hrt. Diese Doppelmarkierung erm{\"o}glichte die Visualisierung und Quantifizierung individueller Synapsenkomplexe (Microglomeruli) im Pilzk{\"o}rper-Calyx. Phalloidin bindet an verschiedene F-Aktin Isoformen und kann zum Nachweis von F-Aktin im Insektennervensystem verwendet werden. F-Aktin wird w{\"a}hrend der Entwicklung in Wachstumskegeln und in adulten Gehirnen in pr{\"a}synaptischen Endigungen und dendritischen Dornen exprimiert. Pr{\"a}synaptische Elemente wurden durch den Einsatz eines spezifischen Antik{\"o}rpers gegen das Drosophila-Vesikeltransportprotein Synapsin I charakterisiert. Mit Hilfe der konfokalen Laser-Scanning Mikroskopie wurde die exakte r{\"a}umliche Zuordnung der Fluoreszenzsignale anhand optischer Schnitte durch die Pr{\"a}parate realisiert. Anhand dieser Methodik konnten erstmals {\"u}ber reine Volumenanalysen hinausgehende Messungen zur synaptischen Strukturplastizit{\"a}t im Pilzk{\"o}rper-Calyx durchgef{\"u}hrt werden. Die Untersuchungen an Gehirnen in den verschiedenen Puppenstadien zeigten Unterschiede im Entwicklungsverlauf der Gehirne mit dem Fokus auf die Bildung antennaler Glomeruli und calycaler Microglomeruli. Unterschiede in der Gehirnentwicklung verdeutlichten die ontogenetische Plastizit{\"a}t des Gehirns der Honigbiene. Entsprechend der k{\"u}rzeren Puppenphase der K{\"o}niginnen bildeten sich sowohl antennale Glomeruli als auch alle Untereinheiten (Lippe, Collar, Basalring) des Calyx etwa drei Tage fr{\"u}her aus. Direkt nach dem Schlupf zeigten quantitative Analysen innerhalb der Pilzk{\"o}rper-Calyces eine signifikant geringere Anzahl an Microglomeruli bei K{\"o}niginnen. Diese neuronale Strukturplastizit{\"a}t auf verschiedenen Ebenen der olfaktorischen Informationsverarbeitung korreliert mit der kastenspezifischen Arbeitsteilung. Die Arbeit liefert Erkenntnisse {\"u}ber den Einfluss eines wichtigen kontrollierten Umweltparameters, der Bruttemperatur, w{\"a}hrend der Puppenphase auf die synaptische Organisation der adulten Pilzk{\"o}rper-Calyces. Bereits geringe Unterschiede in der Aufzuchtstemperatur (1°C) beeinflussten signifikant die Anzahl von Microglomeruli in der Lippenregion des Calyx beider weiblicher Kasten. Die maximale Anzahl an MG entwickelte sich bei Arbeiterinnen bei 34.5°C, bei K{\"o}niginnen aber bei 33.5°C. Neben dieser entwicklungsbedingten neuronalen Plastizit{\"a}t zeigt diese Studie eine starke altersbedingte Strukturplastizit{\"a}t der MG w{\"a}hrend der relativ langen Lebensdauer von Bienenk{\"o}niginnen. Hervorzuheben ist, dass die Anzahl an MG in der olfaktorischen Lippenregion mit dem Alter anstieg (~55\%), in der angrenzenden visuellen Collarregion jedoch abnahm (~33\%). Die in der vorliegenden Arbeite erstmals gezeigte umweltbedingte Entwicklungsplastizit{\"a}t sowie altersbedingte synaptische Strukturplastizit{\"a}t in den sensorischen Eingangsregionen der Pilzk{\"o}rper-Calyces k{\"o}nnte kasten- und altersspezifischen Anpassungen im Verhalten zugrunde liegen.},
  subject      = {Biene},
  language  = {en}
}
@phdthesis{Prusko2006,
  author    = {Prusko, Carsten Dietmar},
  title     = {Evolutionary Diversification of Protein Functions : From Translation in Prokaryotes to Innate Immunity in Invertebrates},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-18517},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2006},
  abstract  = {With the progress in sequencing of the honey bee genome new data become available which allows the search and identification of genes coding for homologous proteins found in other organism. Two genes coding for c-type lysozymes were identified in the genome of A. mellifera through an online-based BLAST search. Expression of both intron-less genes seems not to be under the regulatory control of either of the two pathways involved in humoral insect immunity, i.e. Toll and Imd, since no NF-\&\#954;B transcription factor binding sites are found upstream of the genes. The encoded Lys-1 and Lys-2 are 157 and 143 amino acid long, respectively, and share a sequence similarity of 90\%. Further in silico analysis revealed a signal peptidase cleavage site at the N-terminus of each amino acid sequence, strongly suggesting a secretion of the enzymes into the surrounding environment of the producing cells. Sequence alignments of both amino acid sequences with other c-type lysozymes identified the highly conserved active site glutamic acid (Glu32) as well as eight highly conserved cysteine residues. However, an important aspartic acid (Asp50) in the active site that helps to stabilize a substrate intermediate during catalysis is replaced by a serine residue in the lysozymes of A. mellifera. The replacement of the active site aspartic acid in the honey bee lysozymes suggests a different catalytic mechanism and/or a different substrate-specificity in respect to other c-type lysozymes. Furthermore, 3D-models of Lys-1 and Lys-2 were generated based on the sequence similarity of A. mellifera lysozymes with other c-type lysozymes. The published 3D structure of the lysozyme from the silkmoth Bombyx mori, which shares the highest sequence similarity of all available structures with A. mellifera lysozymes, was used as template for the construction of the 3D-models. The models of Lys-1 and Lys-2 suggest that both enzymes resemble, in large part, the structure of B. mori lysozyme. In order to identify the set of AMPs in the hemolymph of A. mellifera, hemolymph of immunized bees was analyzed. Applying SDS-polyacrylamide gel electrophoresis and mass spectrometry on hemolymph from immunized bees, three out of the four peptides were identified, i.e. abaecin, defensin 1 and hymenoptaecin. Furthermore, Lys-2 was identified in the hemolymph by mass spectrometry, conclusively demonstrating the presence of a lysozyme in the hemolymph of A. mellifera for the first time. However, the protein levels of Lys-2 were not affected by bacterial injection, suggesting that the gene expression of the putative antibacterial protein is not under the regulatory control of the Imd and/or Toll pathway. Besides the abovementioned antimicrobial peptides, the 76 kDa large transferrin was also identified. Transferrin is an iron-binding protein that has been implicated in innate immunity in the honey bee. Furthermore, the effect of pathogenic dose, the timeline of peptide induction and the age-related accumulation of the aforementioned AMPs were studied. The intensity of expression of the antimicrobial peptides, abaecin, defensin 1, and hymenoptaecin as well as transferrin increased proportionally with the amount of bacteria injected into the hemocoel. No such effect was observed for the protein levels of Lys-2. Furthermore, up-regulation of the three antibacterial peptides and transferrin was observed within the first 24 h following infection with E. coli (gram-). Infection with the gram+ bacterium Micrococcus flavus resulted in high and moderate protein levels for transferrin and abaecin, respectively, whereas hardly any accumulation of hymenoptaecin was observed, indicating that the gene expression of abaecin and transferrin is somehow positively correlated, and would suggest a shared regulatory pathway that differs from that of hymenoptaecin. Although bacterial infections didn't seem to stimulate the production of Lys-2, different concentrations in the hemolymph were observed in bees of different ages, suggesting a correlation between the expression of Lys-2 and the age-related division of labor of adult worker honey bees, also known as age polyethism. The results further allow a proposed causal connection between the age-dependent accumulation of Lys-2 and the hemolymph titer of the gonotrophic hormone juvenile hormone, which is the "behavioral pacemaker" in adult honey bees.},
  subject      = {Biene},
  language  = {en}
}
@phdthesis{Basile2009,
  author    = {Basile, Rebecca},
  title     = {Thermoregulation and Resource Management in the Honeybee (Apis mellifera)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39793},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2009},
  abstract  = {Ein grundlegender Faktor, der f{\"u}r das {\"U}berleben einer Kolonie sozialer Insekten ausschlaggebend ist, liegt in der F{\"a}higkeit Nahrung durch sogenannte „Trophallaxis" auszutauschen. Diese F{\"u}tterungskontakte sorgen f{\"u}r die gleichm{\"a}ßige Verteilung der Nahrung innerhalb der Kolonie und werden als einer der Grundpfeiler der Sozialit{\"a}t der Staatenbildenden Insekten erachtet. Im Fall der Honigbienen finden diese Kontakte in vollkommener Dunkelheit statt. Damit es in dieser Situation {\"u}berhaupt zum Nahrungsaustausch kommen kann, sind die Antennen von großer Wichtigkeit. Ein erster Schritt in den Verhaltensweisen, die der Rezipient eines trophallaktischen Kontaktes zeigt, ist der Kontakt einer Antennenspitze mit den Mundwerkzeugen des Donoren, da sich dort die regurgitierte Nahrung befindet. Diese Ber{\"u}hrung hat aufgrund der gustatorischen Sensibilit{\"a}t der Antenne den Zweck, das angebotene Futter zu „erschmecken". Die rechte Antenne wird vom Rezipienten eines trophallaktischen Kontakts signifikant h{\"a}ufiger eingesetzt als die linke Antenne. Die Pr{\"a}ferenz f{\"u}r die rechte Antenne bleibt dabei auch erhalten, wenn ein Teil der Antennengeisel abgetrennt wurde, also die sensorischen F{\"a}higkeiten der rechten Antenne stark beeintr{\"a}chtigt wurden. Der Grund f{\"u}r die Pr{\"a}ferenz der rechten Antenne k{\"o}nnte ihrer erh{\"o}hten Sensibilit{\"a}t gegen{\"u}ber Zuckerwasser zugrunde liegen, da die rechte Antenne im Laborversuch signifikant st{\"a}rker auf Stimulationen mit Zuckerwasser verschiedener Konzentrationen reagierte als die linke. Trophallaktische Kontakte sichern Individuen innerhalb einer Kolonie den Zugang zur lebenswichtigen Nahrung. Im Beispiel der Honigbienen ist st{\"a}ndige Zugriff auf Nahrung besonders wichtig, da es sich um ein heterothermes Tier handelt, das die F{\"a}higkeit besitzt, aktiv seine K{\"o}rpertemperatur zu regulieren. Obgleich jedes Individuum in der Lage ist, seine K{\"o}rpertemperatur den eigenen Bed{\"u}rfnissen anzupassen, ist diese F{\"a}higkeit streng durch den in der Nahrung aufgenommenen Zucker reguliert. Im Gegensatz zu den S{\"a}ugetieren oder V{\"o}geln, die f{\"u}r eine Erh{\"o}hung des Blutzuckerspiegels auch auf Fett- oder Eiweißressourcen zur{\"u}ckgreifen k{\"o}nnen, ist die Honigbiene auf die Glucose aus der aufgenommenen Nahrung angewiesen. Die Ergebnisse dieser Untersuchung zeigen, dass der Zuckergehalt der aufgenommenen Nahrung positiv mit der Thoraxtemperatur der Bienen korreliert. Dieser Zusammenhang tritt auf, selbst wenn keine W{\"a}rmeerzeugung f{\"u}r die Brutpflege oder f{\"u}r das Erw{\"a}rmen der Wintertraube notwendig ist und die Tiere außerhalb des Stockes ohne eigentliche Notwendigkeit f{\"u}r die W{\"a}rmeerzeugung in einem K{\"a}fig gehalten werden. Die Ergebnisse der Untersuchung zeigen, dass die Rezipienten beim Nahrungsaustausch eine signifikant h{\"o}here Thoraxtemperatur haben als die Donoren. Außerdem zeigen die Rezipienten nach der F{\"u}tterung signifikant h{\"a}ufiger Brutw{\"a}rmeverhalten als die Donoren. Letztere haben eine signifikant niedrigere Thoraxtemperatur als die Rezipienten und zeigen eine Verhaltenstendenz, h{\"a}ufig zwischen Brutbereich und Honiglager hin- und her zu pendeln. Dabei nehmen sie im Honiglager Honig in ihren Kropf auf und f{\"u}ttern mit dieser Nahrung danach Bienen im Brutbereich. Außerdem zeigen die Ergebnisse, dass es einen w{\"a}rmegesteuerten Ausl{\"o}semechanismus gibt, der den Donoren und Rezipienten des trophallaktischen Kontakts dazu verhilft, trotz der Dunkelheit des Stocks praktisch verz{\"o}gerungsfreie Nahrungs{\"u}bertragung am Ort des h{\"o}chsten Energieverbrauchs zu gew{\"a}hrleisten. Das Hervorw{\"u}rgen von Nahrung angesichts einer W{\"a}rmequelle k{\"o}nnte seinen Ursprung in einer Beschwichtigungsgeste haben. Aggressive Tiere zeigen neben sichtbaren aggressiven Verhalten auch durch ihre erh{\"o}hte K{\"o}rpertemperatur, dass sie bereit sind sich auf einen Kampf einzulassen. Die Temperaturerh{\"o}hung eines aggressiven Tieres beruht dabei auf der erh{\"o}hten Muskelaktivit{\"a}t, die vor allem bei Insekten dazu n{\"o}tig ist, einen entsprechende Reaktion im Falle eines Kampfes oder der Flucht zeigen zu k{\"o}nnen. Wird ein Individuum mit Aggression konfrontiert, so bleibt ihm die Wahl sich auf einen Kampf einzulassen, zu fl{\"u}chten oder durch eine Beschwichtigungsgeste eine Deeskalation der Situation einzuleiten. Besonders h{\"a}ufig wird f{\"u}r diesen Zweck Nahrung regurgitiert und dem dominanteren Tier angeboten, um einem Konflikt aus dem Weg zu gehen. Die F{\"a}higkeit, Arbeiterinnen mit kleinen Portionen konzentrierter Nahrung zu versorgen tr{\"a}gt zu einer {\"o}konomischen Verteilung der Ressourcen bei, die mit den physiologischen Bed{\"u}rfnissen der Honigbienen konform geht und die {\"o}kologischen Erfordernisse des Stockes erf{\"u}llt. Das daraus resultierende Managementsystem, welches sparsam mit den Ressourcen haushaltet und auf die individuellen Bed{\"u}rfnisse jeder einzelnen Biene einzugehen vermag, k{\"o}nnte ein Grund f{\"u}r die F{\"a}higkeit der Honigbienen zur Entwicklung mehrj{\"a}hriger Kolonien sein, die, anders als Hummeln oder Wespen, auch den Winter in gem{\"a}ßigten Zonen als Gemeinschaft zu {\"u}berstehen verm{\"o}gen.},
  subject      = {Biene},
  language  = {en}
}
@phdthesis{Schneider2011,
  author    = {Schneider, Christof},
  title     = {Detecting the influence of different potential stress factors on the behavior of the honeybee Apis mellifera using Radiofrequency Identification (RFID)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71344},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {This study was conducted to determine the influence of different stress factors on the honeybee Apis mellifera. The investigation was motivated by previous experiments that suggested the existence of an unspecific defense mechanism causing a generalized change of flight behavior after the onset of different diseases. This mechanism is thought to impede the ability of flight bees to return to their respective colonies thereby removing the disease from the colony over time. During the last years, the existence of such a "suicidal behavior" was supported by further studies. Thus, an unnoticed, potentially highly effective defense mechanism of social insects was revealed whose spectrum of activity and physiological basics require further investigation. Suggesting that the reaction by the bees is unspecific to different diseases as well as to other potential stress factors, this study was designed to investigate the influence of pathogens, insecticides, and different brood rearing temperatures on different parameters like lifespan, foraging activity, and foraging trip duration of worker bees.},
  subject      = {Biene},
  language  = {en}
}
@article{PahlZhuTautzetal.2011,
  author    = {Pahl, Mario and Zhu, Hong and Tautz, J{\"u}rgen and Zhang, Shaowu},
  title     = {Large Scale Homing in Honeybees},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68985},
  year      = {2011},
  abstract  = {Honeybee foragers frequently fly several kilometres to and from vital resources, and communicate those locations to their nest mates by a symbolic dance language. Research has shown that they achieve this feat by memorizing landmarks and the skyline panorama, using the sun and polarized skylight as compasses and by integrating their outbound flight paths. In order to investigate the capacity of the honeybees' homing abilities, we artificially displaced foragers to novel release spots at various distances up to 13 km in the four cardinal directions. Returning bees were individually registered by a radio frequency identification (RFID) system at the hive entrance. We found that homing rate, homing speed and the maximum homing distance depend on the release direction. Bees released in the east were more likely to find their way back home, and returned faster than bees released in any other direction, due to the familiarity of global landmarks seen from the hive. Our findings suggest that such large scale homing is facilitated by global landmarks acting as beacons, and possibly the entire skyline panorama.},
  subject      = {Biene},
  language  = {en}
}
@misc{Wenzel2011,
  type      = {Master Thesis},
  author    = {Wenzel, Frank},
  title     = {Smell and repel: Resin based defense mechanisms and interactions between Australian ants and stingless bees},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-65960},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Bees are subject to permanent threat from predators such as ants. Their nests with large quantities of brood, pollen and honey represent lucrative targets for attacks whereas foragers have to face rivalry at food sources. This thesis focused on the role of stingless bees as third party interactor on ant-aphid-associations as well as on the predatory potential represented by ants and defense mechanisms against this threat. Regular observations of an aphid infested Podocarpus for approaching stingless bees yielded no results. Another aim of this thesis was the observation of foraging habits of four native and one introduced ant species for assessment of their predatory potential to stingless bees. All species turned out to be dietary balanced generalists with one mostly carnivorous species and four species predominantly collecting nectar roughly according to optimal foraging theory. Two of the species monitored, Rhytidoponera metallica and Iridomyrmex rufoniger were considered potential nest robbers. As the name implies, stingless bees lack the powerful weapon of their distant relatives; hence they specialized on other defense strategies. Resin is an important, multipurpose resource for stingless bees that is used as material for nest construction, antibiotic and for defensive means. For the latter purpose highly viscous resin is either directly used to stick down aggressors or its terpenic compounds are included in the bees cuticular surface. In a feeding choice experiment, three ant species were confronted with the choice between two native bee species - Tetragonula carbonaria and Austroplebeia australis - with different cuticular profiles and resin collection habits. Two of the ant species, especially the introduced Tetramorium bicarinatum did not show any preferences. The carnivorous R. metallica predominantly took the less resinous A. australis as prey. The reluctance towards T. carbonaria disappeared when the resinous compounds on its cuticle had been washed off with hexane. To test whether the repulsive reactions were related to the stickiness of the resinous surface or to chemical substances, hexane extracts of bees' cuticles, propolis and three natural tree resins were prepared. In the following assay responses of ants towards extract treated surfaces were observed. Except for one of the resin extracts, all tested substances had repellent effects to the ants. Efficacy varied with the type of extract and species. Especially to the introduced T. bicarinatum the cuticular extract had no effect. GCMS-analyses showed that some of the resinous compounds were also found in the cuticular profile of T. carbonaria which featured reasonable analogies to the resin of Corymbia torelliana that is highly attractive for stingless bees. The results showed that repellent effects were only partially related to the sticky quality of resin but were rather caused by chemical substances, presumably sesqui- and diterpenes. Despite its efficacy this defense strategy only provides short time repellent effects sufficient for escape and warning of nest mates to initiate further preventive measures.},
  subject      = {Stachellose Biene},
  language  = {en}
}
@phdthesis{Pahl2011,
  author    = {Pahl, Mario},
  title     = {Honeybee Cognition: Aspects of Learning, Memory and Navigation in a Social Insect},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-66165},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Honeybees (Apis mellifera) forage on a great variety of plant species, navigate over large distances to crucial resources, and return to communicate the locations of food sources and potential new nest sites to nest mates using a symbolic dance language. In order to achieve this, honeybees have evolved a rich repertoire of adaptive behaviours, some of which were earlier believed to be restricted to vertebrates. In this thesis, I explore the mechanisms involved in honeybee learning, memory, numerical competence and navigation. The findings acquired in this thesis show that honeybees are not the simple reflex automats they were once believed to be. The level of sophistication I found in the bees' memory, their learning ability, their time sense, their numerical competence and their navigational abilities are surprisingly similar to the results obtained in comparable experiments with vertebrates. Thus, we should reconsider the notion that a bigger brain automatically indicates higher intelligence.},
  subject      = {Biene},
  language  = {en}
}
@phdthesis{Hendriksma2011,
  author    = {Hendriksma, Harmen P.},
  title     = {Non-target effects of a multiple insect resistant Bt-maize on the honey bee (Apis mellifera L.)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-70304},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Neue methodische Entwicklungen zur Untersuchung der Ursachen des weltweit beobachteten Bienensterbens sind n{\"o}tig, um die lebenswichtige {\"O}kosystemdienstleistung der Best{\"a}ubung zu gew{\"a}hrleisten. Die {\"o}kologisch und wirtschaftlich bedeutsame Honigbiene (Apis mellifera) ist ein wichtiger Nichtziel-Organismus im Zulassungsverfahren f{\"u}r gentechnisch ver{\"a}nderte Pflanzen. Bisher sind vor allem Methoden zur Testung erwachsener Bienen unter Laborbedingungen verwendet worden, aber f{\"u}r eine Risikobewertung mit Hilfe von standardisierten Bienenkolonien oder in vitro gez{\"u}chteten Honigbienenlarven sind keine robusten Methoden oder standardisierte Protokolle vorhanden. In dieser Arbeit wurde eine Vielzahl an neuen methodischen Ans{\"a}tzen f{\"u}r die Biosicherheitsforschung entwickelt: eine Mortalit{\"a}ts-Falle (Kapitel II), ein "Full-Life-Cycle" Test (III), eine robuste in vitro Aufzucht-Methodik (IV), ein standardisierter in vitro Test f{\"u}r Bt-Pollen (V), eine gemischte Toxizit{\"a}tspr{\"u}fung f{\"u}r transgene Reinproteine (VI) und eine {\"U}berpr{\"u}fung der Darmmikroflora sowie der Pollenverdauungrate (VII). Die Ergebnisse dieser Studien zeigten keine nachteiligen Wirkungen von Bt-Maispollen oder Bt-Reinproteinen im "Worst-Case" Szenario auf Honigbienen. In Anbetracht der Datenlage ist eine Sch{\"a}digung der Honigbiene durch den getesteten Bt-Mais Mon89034xMon88017 unwahrscheinlich. Die Anwendung der Untersuchungsmethoden in zuk{\"u}nftigen Biosicherheitsstudien f{\"u}r transgene Pflanzen wird empfohlen.},
  subject      = {Biene},
  language  = {en}
}