The sensitivity of the honey bee, Apis mellifera L. (Hymeonoptera: Apidae), brain volume and density to behavior (plasticity) makes it a great model for exploring the interactions between experience, behavior, and brain structure. Plasticity in the adult bee brain has been demonstrated in previous experiments. This experiment was conducted to identify the potentials and limitations of MicroCT (micro computed tomograpy) scanning "live" bees as a more comprehensive, noninvasive method for brain morphology and physiology. Bench-top and synchrotron MicroCT were used to scan live bees. For improved tissue differentiation, bees were fed and injected with radiographic contrast. Images of optic lobes, ocelli, antennal lobes, and mushroom bodies were visualized in 2D and 3D rendering modes. Scanning of live bees (for the first time) enabled minimally-invasive imaging of physiological processes such as passage of contrast from gut to haemolymph, and preliminary brain perfusion studies. The use of microCT scanning for studying insects (collectively termed 'diagnostic radioentomology', or DR) is increasing. Our results indicate that it is feasible to observe plasticity of the honey bee brain in vivo using diagnostic radioentomology, and that progressive, real-time observations of these changes can be followed in individual live bees. Limitations of live bee scanning, such as movement errors and poor tissue differentiation, were identified; however, there is great potential for in-vivo, non-invasive diagnostic radioentomology imaging of the honey bee for brain morphology and physiology.

Nest structures of the Australian blue-banded bee, Amegilla holmesi Rayment (Hymenoptera: Apidae), are difficult to monitor non-invasively, because the bee is a fossorial species that constructs tunnels and natal cells within the soil. Visualization of nest structures requires physical separation of the structures from the soil substrate, which destroys the nest. Using helical, two-dimensional (2D) X-ray computerized tomography (CT), and three-dimensional (3D) volume rendering software on 13 artificial mud-brick nests, we were able to view all previously reported nest structures and cell contents without damaging the nests. We used three volume rendering algorithms (sum along ray, scatter HQ, and false colour), two of which (scatter HQ and false colour) have not previously been used to visualize nest architecture. Each algorithm has a particular advantage for visualizing specific nest structures. The 2D CT images provided the greatest spatial resolution within and between nest structures (capture pixel matrix size 512 × 512; voxel size 0.449 mm 3 ), and for the first time we were able to visualize a meniscus within natal cells that contained liquid provisions, which is a valuable characteristic in detecting the earliest stage of juvenile development once a natal cell is sealed. We also recorded and attributed Hounsfield units to nest structures and their contents that can be utilized in future studies. This new method also enabled us to count and measure natal cells using on-screen linear callipers, visually observe and record stages of larval and pupal development, and visually gauge the incidence of cell parasitism without damaging the nest. Artificial nests can be transported easily to research facilities that have CT scanners; each scan including image processing takes less than 30 min per nest and currently costs less than AUD 20.00, which is within the reach of apiculturists. X-ray CT could be used to follow the life cycle of blue-banded bees and other cryptic species and also to monitor their health.

Bumblebees have been the focus of a broad range of scientific research due to their behavior, social life, and a number of other intriguing traits. Current methods for examining their nest structure, such as natal cells and contents of storage cells, are destructive in nature because the cells need to be opened for physical inspections. This research describes how the internal structures of the artificial nests of the bumblebee Bombus terrestris L. (Hymentoptera: Apidae) were non-invasively viewed and assessed by using diagnostic radioentomology. For the first time, B. terrestris nest structures, and their contents such as larvae, pupae and eggs, were noninvaseively viewed and assessed. This technique will enable future experiments to take morphological measurements of egg, larval, and pupal development over time. Moreover, combining these measurements with measures of food-storage will provide a good assessment of colony health. The method will also allow tracking of individually marked adults, to monitor their behaviour and help gain a better understanding of the processes involved in the global declines of B. terrestris, which will in turn promote better management of these valuable pollinators.

Workers from social insect colonies use different defence strategies to combat invaders. Nevertheless, some parasitic species are able to bypass colony defences. In particular, some beetle nest invaders cannot be killed or removed by workers of social bees, thus creating the need for alternative social defence strategies to ensure colony survival. Here we show, using diagnostic radioentomology, that stingless bee workers (Trigona carbonaria) immediately mummify invading adult small hive beetles (Aethina tumida) alive by coating them with a mixture of resin, wax and mud, thereby preventing severe damage to the colony. In sharp contrast to the responses of honeybee and bumblebee colonies, the rapid live mummification strategy of T. carbonaria effectively prevents beetle advancements and removes their ability to reproduce. The convergent evolution of mummification in stingless bees and encapsulation in honeybees is another striking example of co-evolution between insect societies and their parasites.

Australian stingless bees contribute to the pollination of some commercially important field crops, but it is unclear whether they can increase crop production reliably in the greenhouse environment. Three 20 week trials were therefore conducted, each using a different hive of Austroplebeia australis Friese and Trigona carbonaria Smith placed in separate glasshouses containing Capsicum annuum L. A third glasshouse contained C. annuum but no bees. In the third week of each trial, the numbers of pollen grains present on stigmatic surfaces and pollen tubes growing along styles were determined. Changes in brood volume were assessed by x-ray computerised tomography at weeks 1, 10 and 20.

Australian stingless bees contribute to the pollination of commercially important crops. Optimum bee stocking rates have, however, yet to be established. To determine stocking rates, five pollination trials were conducted. For each trial, 50 plants of Capsicum annuum L. var. grossum (L.) Sendt cv. Aries were placed in each of two glasshouses and a colony of T. carbonaria randomly assigned to one of the two glasshouses.

Here, we describe a single micro-CT scan with a spatial resolution of 10 lm of a 10-day-old adult male Schistocerca gregaria (Forsk al) (Orthoptera: Acrididae) and we compare our tracheal volume (V T ) determination with published work on the subject. We also illustrate the feasibility of performing non-invasive 'virtual dissection' on insects after performing micro-CT. These post-processing steps can be performed using free downloadable 3-D software. Finally, the values of producing stereo-lithography (STL) files that can be viewed or used to print out 3-D models as teaching aids are discussed.

Decision making in honeybees is based on information which is acquired and processed in order to make choices between two or more alternatives. These choices lead to the expression of optimal behaviour strategies such as floral constancy. Optimal foraging strategies such as floral constancy improve a colony's chances of survival, however to our knowledge, there has been no research on decision making based on optimal storage strategies. Here we show, using diagnostic radioentomology, that decision making in storer bees is influenced by nectar sugar concentrations and that, within 48 hours of collection, honeybees workers store carbohydrates in groups of cells with similar sugar concentrations in a nonrandom way. This behaviour, as evidenced by patchy spatial cell distributions, would help to hasten the ripening process by reducing the distance between cells of similar sugar concentrations. Thus, colonies which exhibit optimal storage strategies such as these would have an evolutionary advantage and improve colony survival expectations over less efficient colonies and it should be plausible to select colonies that exhibit these preferred traits. . The standard curve produced for this experiment plotting Hounsfield Units (HU) according to sugar concentrations, without 10% Visipaque contrast agent (red) and with 10% Visipaque contrast agent (green).