O. van Laere

Toxicity of pyriproxifen and fenoxycarb to bumble bee brood using a new method for testing insect growth regulators

SUMMARYThese insect growth regulators were administered in 1:1 sucrose solution to young bumble bee (Bombus terrestris) colonies kept in the dark in a controlled climate chamber and fed with 50% sucrose solution and bee-collected pollen. Three colonies received Admiral (pyriproxifen at either 20 ppm a.i., or 2 ppm a.i., or 0.2 ppm a.i.) and one received Insegar (fenoxycarb 100 ppm a.i.). One colony was fed with Nomolt (teflubenzuron 150 ppm a.i.), which was known to be toxic to bumble bee brood. A sixth colony, fed with pure sucrose solution, acted as a negative control. After the 24-h feeding period the amounts of ingested sucrose solutions were determined and the colonies, which had been photographed daily for one week before treatment, were photographed daily for the next five weeks. There was no significant difference between colonies in the amount of food consumed on the day of treatment. The only colony to show larval mortality and arrested egg development was the one fed on teflubenzuron-sucrose so...

Novel Applications Integrate Location and Context Information

New applications and services aim to adapt themselves to the users context and thus require platforms that can collect, distribute, and exchange contextual information. The Context-Aware Service Platform (CASP) can help, as exemplified here in three different use cases.

Physiology of the Honeybee Corpora Allata 3. A New Method for Allatectomy of Queens

SummaryA new method for allatectomy of queen honeybees is described. This technique makes it possible to carry out the allatectomy in the air instead of under physiological solution. After allatectomy, three young queens lived for 22, 35 and nearly 50 days, respectively, and during this time they laid eggs; the two longer-lived queens showed a fairly normal rate of brood production up to about 10 days before death, when the rate decreased. In the period following allatectomy, the workers continued to form a retinue around each queen, and no queen cells were produced in the colonies. This would seem to indicate that production of pheromone by the queens proceeded adequately for the colonies used.

Ultrastructure of the Corpora Cardiaca in the Honeybee

SummaryThe ultrastructure of the corpora allata of the honeybee is described from the electron micrographs presented. The gland is composed of large uniform cells whose walls interdigitate. The nucleus contains various nucleoli, which are surrounded by dispersed associated chromatin fragments. The perikaryon is characterized by a large number of longitudinally striped mitochondria, a dispersed granular endoplasmic reticulum, isolated or grouped lysosomes, and several small vacuoles. There are numerous desmosomes on the cell membrane.The gland wall is an amorphous layer of connective tissue, which by means of extensive ramification forms a “stroma” of intercellular spaces between the glandular cells. In the neighbourhood of the gland wall or of large intercellular spaces there are sometimes local bladder-like widenings of the space between adjacent cell membranes; the function of these is not known.The axons of the nervus allatus lie over the entire gland interspersed between the cells. Sometimes they cros...

Use of the Scanning Electron Microscope for Investigating Pollen Grains isolated from Honey Samples

SummaryExamination of pollen grains with an optical microscope yields imperfect images, owing to the highly refractive properties and opaque character of the grains, and to the very restricted depth of focus. A preliminary report is given on the use of the scanning electron microscope for pollen analysis of honey. The images provide an extremely good representation of the surface texture of the pollen grains, and are characterized by a considerable depth of focus.

Morphology of the Neuro-Endocrine System of the Honeybee. A New Method for Cutting Thin Serial Paraffin Sections

SummaryAn approved technique is described for cutting paraffin sections of relatively small objects (up to about 5 mm diameter), in the range of 1–4 μ.New observations are reported on the morphology of the endocrine system of the worker honeybee imago. The corpora allata are connected by a striated muscle ring round the oesophagus, and an additional strip of tissue connects the corpora allata to the suboesophageal ganglion.

Interest Based Selection of User Generated Content for Rich Multimedia Services

In view of the overwhelming popularity of user generated content, both in terms of production and consumption, new intelligent services are needed to help users finding the content they need and enhance existing services with suitably selected content. In this paper we present a set of algorithms for retrieving content, based on dynamic user profiles and learning capabilities (e.g. based on user feedback). The profile information is used in content searches as well as for assisting the user input analysis process (i.e. speech recognition). To illustrate the approach taken, a rich communication service is presented. Here, the basic service (i.e. voice/video conferencing) is enhanced by showing pictures in real time to the users based on the topic of their conversation and their specific interests.

Efficient Management of User Interests for Personalized Communication Services

Nowadays, there is a lot of interest in context- aware services, especially those services taking into account user interests. An important example is the automated filtering of the overwhelming amount of information available to the user. There is a clear need for the automated capturing of user interests without explicit user interaction. In this paper we present a set of algorithms for the management of user interests. This information is used for updating a tree structure, with added weight values, representing user interests. To illustrate the approach taken, we detail the use case of an instant messaging communication service which updates the user profiles and searches for content matching the topic of the ongoing conversation and the specific interests of the user. The retrieved content is recommended to the user, who is then able to provide feedback by selecting the content he prefers. The gain of the detailed approach is illustrated by means of simulation results, taking real-time constraints into account.

Fluorescence Microscopy of the Intercerebralis-Cardiacum-Allatum Complex in the Honeybee

SummaryThe parts of the neuro-endocrine system of the honeybee (pars intercerebralis, corpora cardiaca and corpora allata) were examined by the fluorescence microscope after suitable staining and fixation. Extremely small quantities of neurosecretion could be identified.Two kinds of neurosecretory cells were distinguished in the pars intercerebralis, and neurosecretory material could be localized very precisely in the axon bundles, the corpora cardiaca and the corpora allata.

Physiology of the Honeybee Corpora Allata 2. Influence of Temperature and of Carbohydrate and Protein Consumption on the Development of the Glands

SummaryCages of 85 young worker honeybees were kept at 35°, 28° and 24°. Sucrose was fed to the bees in all cages; one series was in addition supplied with protein (fresh pollen). Every 2–3 days six corpora allata were measured from bees in each cage.There was a significant increase in sucrose consumption at the lower temperatures, which did not, however, affect the development of the corpora allata. The development of the corpora allata was greater in bees provided with protein than in those fed on sucrose only.