Finite Element Model Updating has recently arisen as an issue of vast importance on the design, construction and maintenance of structures in civil engineering. Many algorithms have been proposed, developed and enhanced in order to accomplish the demands of the updating process, mainly to achieve computationally efficient programs and greater results.The present Master Thesis proposes two new algorithms to be used in Finite Element Model Updating: the Bees Algorithms (BA) and the Artificial Bee Colony algorithm (ABC). Both were first proposed in 2005, are based on the foraging behaviour of bees and have been proved to be efficient algorithms in other fields. The objective of this Master Thesis is, thus, to implement and to test these two newalgorithms in Finite Element Model Updating for a cantilever beam. The Finite Element Model and the algorithms are programmed, followed by the extraction of the experimental frequencies and the updating process. Results, comparison of these two methods and conclusions are given at the end of this report, as well as suggestions for further work.

Bovine viral diarrhoea virus infection is an important viral infection affecting the cattle industry today. The prevalence of this infection in South African feedlots is unknown. Ear notch biopsies were collected from animals entering feedlots which appeared unthrifty, chronic poor doers, and animals entering the hospital pen with respiratory disease for the first time. One thousand and seventy four (1074) samples were collected from the first two categories and 616 samples from animals entering the hospital pen. Samples were processed with routine immunoperoxidase protocol. Serum samples were also collected when possible. The first aim of this study was to determine the prevalence with the use of immunoperoxidase staining on ear notch biopsies. Overall 49 animals tested positive, 43 from the 1074 group and 6 from the 616 group. The prevalence of persistently infected cattle entering the feedlots was determined as 2.9%, which is higher than the rule of thumb that 0.5% of infected animals enter feedlots. Four percent were positive in the group of 1074 animals and one percent in those entering the hospital pen for the first time. It was proposed by the author that persistently infected animals are at a greater risk to develop respiratory disease in the feedlot, but this was not supported by the data collected. There was thus no clear increase in respiratory disease in persistently infected animals. The reliability of the immunoperoxidase stain as a diagnostic method to identify persistently infected animals was also evaluated. This diagnostic method proved to be reliable, but the pathologist needs to be aware of non-specific staining. During the course of the research it became apparent that in some cases mast cells in the dermis stain positive with both DAB and NovaRED stains. Positive staining in keratinocytes and hair follicle epithelium was not present and these cases were proven as negative for persistent infection. The specific cause of positive staining of mast cell granules remains unclear. Only ten positive cases had serum samples on which ELISA tests for antigen and antibody were performed. All tests correlated well with the immunoperoxidase method except in four cases, where the animals were incorrectly diagnosed as positive due to the non-specific staining as described above. Immunoperoxidase staining on ear notch biopsies is thus a reliable diagnostic method to identify persistently infected animals with BVDV, but the pathologist must be aware of non-specific positive staining. / Bees virus diarree infeksie is ‘n belangrike virale infeksie wat die bees industrie van vandag beinvloed. Die prevalensie van die infeksie in Suid Afrikaanse voerkrale is onbekend. Oorknip biopsies is geneem van verdagte diere met aankoms by die voerkraal, chroniese swak beeste en diere wat vir die eerste keer in die hospitaal kraal weens respiratoriese siekte opgeneem is. Een duised vier en sewentig (1074) monsters is van die eerste twee kategoriee geneem en 616 monsters van diere wat in die hospitaal kraal opgeneem is. Monsters is op roetiene wyse vir immunoperoksidase kleuring geprosesseer. Serum monsters is waar moontlik ook versamel. Die eerste doel van die studie was om die prevalensie van permanente besmette draers te bepaal met behulp van immunoperoksidase kleuring op oorknip biopsies. Nege-en-veertig diere in totaal het positief getoets, 43 vanuit die eerste groep en 6 vanuit die tweede groep. Die prevalensie van permanente besmette draers wat in voerkrale opgeneem word is was 2.9% wat hoër is as die verwagte 0.5% wat deur die literatuur aangedui word. Vier persent was positief in die 1074 groep en 1% in die groep wat vir die eerste keer in die hospitaal kraal opgeneem is. Dit is deur die navorser voorgestel dat permanente besmette draers ‘n groter risiko het om met respiratoriese siektes in die hospitaal kraal opgeneem te word, maar dit is nie deur die data bevestig nie. Daar was dus geen verhoging in die teenwoordigheid van respiratoriese siektes in geaffekteerde diere nie. Die betroubaarheid van immunoperoksidase kleuring om permanente besmette diere met BVD te identifiseer is ook geevalueer. Die metode is betroubaar gevind, maar die patoloog moet bewus wees van nie-spesifieke kleuring. Gedurende die navorsing het dit aan die lig gekom dat mastselle in die dermis positief kleur met DAB en NovaRED kleuring. Positiewe kleuring was nie in die epidermis of haarfollikel epiteel teenwoordig nie en die die gevalle was negatief vir permanente besmetting. Die spesifieke rede vir positiewe kleuring in mastselle is steeds onduidelik. Slegs 10 positiewe gevalle het serum monsters gehad vir ELISA teenliggaam en antigeen toetse. Die resultate het goed gekorrelleer met die immunoperoksidase kleuring, behalwe in 4 gevalle waar gevalle verkeerd as positief gediagnoseer is as gevolg van nie-spesifieke positiewe kleuring soos beskryf. Immunoperoksidase kleuring is dus ‘n sensitiewe metode om permanente besmette draers met BVDV te identifiseer, mits die patoloog bewus is van nie-spesifieke kleuring wat mag voorkom. / Dissertation (MMedVet)--University of Pretoria, 2010. / Paraclinical Sciences / unrestricted

Under 2013 förbjöds behandling av blommande grödor med de systematiska neonikotinoiderna imidakloprid, klotianidin och tiametoxam i EU. Ett flertal studier och rapporter hade visat att pollinerande biarter kan uppleva subletala effekter av att konsumera neonikotinoid. Oro rådde om bin blir förgiftade av neonikotinoider funna i pollen och nektar hos dessa blommade grödor. Därför har jag undersökt på en kommunal nivå om neonikotinoidbetade rapsareal generellt har medfört en negativ effekt på förekomst av rapspollinerande vildbin. Studien använde observationsdata från medborgarforskning angående 46 vildbiarter som är vanliga i och omkring åkrar, varav 19 är vanliga i rapsfält. Jag sammanställde data över pollinatörer och areal åker med andel raps mellan 2002 och 2020 för 202 kommuner i södra Sverige. Med hjälp av ”Generalized linear mixed model” undersökte jag sambandet mellan oddset att observera rapspollinerande arter bland pollinatörerna och rapsareal. Resultatet visade ingen effekt av ökad mängd raps på rapsbesökare och ingen lägre mängd pollinatörer mellan 2008–2013 då neonikotinoidbetad raps förekom som mest. Frånvaro av negativ effekt på vildbin kan vara på grund av låga koncentrationer av neonikotinoider i nektar och pollen över skalan för denna studie. En eventuell negativ effekt av neonikotinoider från mer raps kan möjligtvis ha vägts upp av den positiv effekt i form av extra resurser som ökar tillväxten hos lokala populationer. Framtida studier uppmanas att vidare undersöka variationen i exponering av neonikotinoider från raps beroende på beteendemässiga skillnader som tillexempel flygtid och socialstruktur. / In 2013, treatment of flowering crops with the systematic neonicotinoids imidacloprid, clothianidin and thiamethoxam were prohibited by the EU. Several studies and reports had shown that pollinating bees can experience sublethal effects by consuming neonicotinoids. Concerns regarded whether bees would be poisoned by neonicotinoids found in pollen and nectar of these flowering crops. Therefore, I have examined on a municipal level, whether area of rapeseed treated with neonicotinoids have generally caused a negative effect on the abundance of wild bees which pollinate on rapeseed. The study used citizen-based observational data of 46 wild bee-species that are common in and around agricultural fields, 19 of which are common in rapeseed-fields. I compiled data regarding pollinators and area of agricultural field with proportions of rapeseed-fields between 2002 and 2020 for 202 municipalities in South Sweden. Using Generalized linear mixed model, I examined the connection between odds of observing rapeseed-pollinating species among pollinators and the area of rapeseed. The result showed no effect from increased amount of rapeseed on rapeseedpollinators and no reduced number of pollinators between 2008-2013, the periodwhenneonicotinoid-treated rapeseed was most abundant. The absence of a negative effect on wild bees could be caused by low concentrations of neonicotinoids in nectar and pollen. Also, possible negative effects of neonicotinoids from rapeseed could possibly be outweighed by a positive effect from additional resources that increases local population growth. Future studies are encouraged to further examine varied exposure of neonicotinoids from rapeseed based of behavioural differences like flight-time and social structure of wild bees.

The daily patterns of task performance in honey bee colonies during behavioral development were studied to determine the role of circadian rhythmicity in age-related division of labor. Although it is well known that foragers exhibit robust circadian patterns of activity in both field and laboratory settings, we report that many in-hive tasks are not allocated according to a daily rhythm but rather are performed 24 h per day. Around-the-clock activity at the colony level is accomplished through the performance of some tasks by individual workers randomly with respect to time of day. Bees are initially arrhythmic with respect to task performance but develop diel rhythmicity, by increasing the occurrence of inactivity at night, prior to becoming foragers. There are genotypic differences for age at onset of rhythmicity and our results suggest that these differences are correlated with genotypic variation in rate of behavioral development: genotypes of bees that progressed through the age polyethism schedule faster also acquired behavioral rhythmicity at an earlier age. The ontogeny of circadian rhythmicity in honey bee workers ensures that essential in-hive behaviors are performed around the clock but also allows the circadian clock to be engaged before the onset of foraging.

Abstract: The honey bee time memory enables foragers to return to a profitable food source in anticipation of the time of day at which they previously collected food from that source. The time memory thus allows foragers to quickly resume exploiting a source after interruption, at the appropriate time of day, without the costs associated with having to rediscover it. A portion of a foraging group (the persistent foragers) will reconnoiter a previously profitable source and may do so for several days. The remaining bees (the reticent foragers) await confirmation of availability before revisiting the source. Recent work has shown that both persistent and reticent bees make extracurricular flights to alternative sources when one food source ceases being productive. Little else, however, is known about reticent foragers. In the present study, we determined that reticent bees congregate near the hive entrance in anticipation of the learned foraging time as do persistent foragers. We then confirmed that the food-anticipatory clustering takes place on the waggle dance floor, as suspected, but also found differences in the number of days that persistent and reticent foragers continue clustering. Finally, we found that persistent foragers had significantly more rewards per day at the source than did reticent foragers, supporting the hypothesis that experience at a food source influences a forager’s decision to become either persistent or reticent. Our findings demonstrate that persistence and reticence are not immutable characteristics of foragers themselves but rather strategies they employ toward different food sources. Significance statement: Much has been learned in recent years about the honey bee time memory and foraging behavior. Receiving scant attention, however, is the phenomenon of forager bees gathering near the hive entrance, anticipating the time of day when previously productive food sources become available. We show that both persistent and reticent bees (foragers that do and do not investigate the source, respectively) congregate on the waggle dance floor at the appropriate time of day, but, in the absence of food at the source, persistent bees continue to show this behavior a day or two longer than reticent bees do. We also show that experience with the source influences the decision to become persistent or reticent. Our results reveal how foraging experience influences the individual bee’s decision making, thereby providing insights into how foragers are reallocated efficiently among different resources in the environment.

Forager honey bees exhibit a robust time memory, based on an endogenous circadian clock, enabling them to schedule their flights to coincide with the nectar presentation of known food sources. They retain this time memory for several consecutive days even in the absence of nectar rewards. Recent work has identified 2 classes of forager: "persistent" foragers that reconnoiter a known food source to ascertain its status and "reticent" foragers that apparently wait in the hive for a waggle dance confirming source availability. Surprisingly, a foraging group contains 40-90% persistent foragers, depending on experience at the source. What is the benefit in sending so many foragers to investigate a source when only a few foragers are required to reactivate the entire group? We used an agent-based software model to test the energetics underlying several different ratios of persistent and reticent individuals in the foraging group while varying 6 ecological factors: forager group size, source distance, source sucrose concentration, source availability in hours, number of days the source is known to the colony, and the rate at which new unemployed foragers appear on the dance floor. Our model demonstrates 2 primary explanations. First, a large number of persistent foragers are needed to ensure that at least some foragers will reconnoiter their source early in its availability, thus enabling the group to effectively exploit the source. Second, the cost of a reconnaissance flight is negligible compared with even a single successful foraging trip.

Classical experiments demonstrated that honey bee foragers trained to collect food at virtually any time of day will return to that food source on subsequent days with a remarkable degree of temporal accuracy. This versatile time-memory, based on an endogenous circadian clock, presumably enables foragers to schedule their reconnaissance flights to best take advantage of the daily rhythms of nectar and pollen availability in different species of flowers. It is commonly believed that the time-memory rapidly extinguishes if not reinforced daily, thus enabling foragers to switch quickly from relatively poor sources to more productive ones. On the other hand, it is also commonly thought that extinction of the time-memory is slow enough to permit foragers to 'remember' the food source over a day or two of bad weather. What exactly is the time-course of time-memory extinction? In a series of field experiments, we determined that the level of food-anticipatory activity (FAA) directed at a food source is not rapidly extinguished and, furthermore, the time-course of extinction is dependent upon the amount of experience accumulated by the forager at that source. We also found that FAA is prolonged in response to inclement weather, indicating that time-memory extinction is not a simple decay function but is responsive to environmental changes. These results provide insights into the adaptability of FAA under natural conditions.

Forager honey bees can associate the time of day with the presence of food at locations outside the hive. It is thought that this time-memory enables the bee to make a spatio-temporal match between its behavior and floral nectar secretion rhythms. Despite a long tradition of research, the mechanisms by which the time-memory becomes established are unknown. We investigated the influences of two experiential factors on the acquisition of time-memory: (1) the number of collecting visits made by the forager within a feeding bout during a restricted time of day and (2) the number of days of exposure to the restricted feeding time. Our results indicate that these two factors control different processes. The number of days of experience influences the temporal accuracy of reconnaissance behavior to the food source. The cumulative number of collecting visits within the feeding bouts has no apparent effect on time-accuracy but, instead, determines the probability of exhibiting food-anticipatory behavior and, if that overt behavior is performed, the intensity of its expression.

Insects fulfill important roles within all ecosystems, including deserts, and interact directly and indirectly with the endemic and endangered species at the Ash Meadows National Wildlife Refuge (AMNWR). Here I investigate the variability of species richness, diversity, abundance and community composition of four insect groups between stabilized sand dune habitats, unstabilized sand dune habitats and non-sand dune habitats. The insects examined in this thesis include antlions (Myrmeleontidae), bees (Apiformes), darkling beetles (Tenebrionidae) and velvet ants (Mutillidae). As the impact and interactions of two of the insect groups, antlions and velvet ants, are largely unknown within any ecosystem, this thesis also includes a faunal study of velvet ants at AMNWR and their spatial and temporal variation at the refuge. Generalized linear mixed models were used to identify significant differences in richness, diversity and abundance for each insect group between the stabilized sand dune, unstabilized sand dune and non-sand dune habitats. Species richness differed between habitats for antlions, beetles and velvet ants over the study period. Diversity differed between habitats for antlions and beetles, and abundance differed between habitats for all groups over the study period. Nearly every habitat supported some unique species. The faunal survey of velvet ants revealed minor variation in flight times between species and a unique pattern of temporal niche partitioning in one species. Habitat preferences were observed for seven of 42 velvet ant species at AMNWR. In a comparison of the diversity of velvet ants between AMNWR and the Nevada Test Site (NTS), six velvet ant species that occurred at the NTS were not found at AMNWR. Diagnoses and a key are provided for the velvet ants of AMNWR. This thesis increases the number of known terrestrial invertebrates at the refuge and provides a comparison of terrestrial insect distribution and habitat use at AMNWR. These investigations contribute to the goals and objectives of the U. S. Fish and Wildlife Service to obtain basic inventories and understand the terrestrial habitat use of invertebrates at AMNWR.

Several reports of North American bumble bee (Bombus Latreille) decline have been documented across the continent, but no study has fully assessed the geographic scope of decline. In this study I discuss the importance of Natural History Collections (NHC) in estimating historic bumble bee distributions and abundances, as well as in informing current surveys. To estimate changes in distribution and relative abundance I compare historic data assembled from a >73,000 specimen database with a contemporary 3-year survey of North American bumble bees across 382 locations in the contiguous U.S.A. Based on my results, four historically abundant bumble bees, B. affinis, B. occidentalis, B. pensylvanicus and B. terricola, have declined by 72 - 96% relative abundance across their native distribution, while B. bifarius, B. bimaculatus, B. impatiens, and B. vosnesenskii appear to be relatively stable. Finally, I provide some notes on the distribution, abundance, and frequency of Nosema bombi infections in Alaskan B. occidentalis.