ALTERATIONS IN THE OMMATIDIA OF THE COMPOUND EYES OF APIS-MELLIFERA EYE-COLOR MUTANT WORKERS .3.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mispatterning in the ommatidia of Apis mellifera pupae treated with a juvenile hormone analogue

To further understand the function of morphogenetic hormones in honeybee eye differentiation, the alterations in ommatidial patterning induced by pyriproxyfen, a juvenile hormone (JH) analogue, were studied by scanning and transmission electron microscopy. Prepupae of prospective honeybee workers were treated with pyriproxyfen and the effects on ommatidial differentiation were described at the end of the pupal development. The results show that the entire ommatidia, i.e., the dioptric as well as the receptor systems, were affected by the JH analogue. The wave of ommatidial differentiation, which progresses from the posterior to the anterior region of the pupal eyes, was arrested. In treated pupae, the rhabdomeres only differentiated at the apical axis of the retinula, the secondary and tertiary pigment cells did not develop their cytoplasm protrusions, and the cone cell quartet did not pattern correctly. Simultaneously, an intense vacuolization was observed in cells forming ommatidia. In a previous study we showed that pyriproxyfen exerts an inhibition on pupal ecdysteroid secretion. In this sense, the arrested ommatidial differentiation in pyriproxyfen-treated pupae could be due to a secondary effect resulting from an alteration in pupal ecdysteroid titers. J. Morphol. 249:89-99, 2001. (C) 2001 Wiley-Liss, Inc.

The venom gland of queens of Apis mellifera (Hymenoptera, Apidae): morphology and secretory cycle

The venom gland of queens of Apis mellifera was examined through light and transmission electron microscopy and subjected to electrophoretic analyses. Virgin queens exhibited prismatic secretory cells containing large amounts of rough endoplasmic reticulum with dilated cisternae, open secretory spaces, numerous vacuoles and granules scattered in the cytoplasm, and spherical nuclei with numerous nucleoli. The secretion produced was non-refringent under polarized light and the electrophoretic analysis of glandular extracts revealed five main protein bands. In mated queens, the venom gland exhibited a high degree of degeneration. Its secretion was refringent under polarized light and one of the main bands was absent in the electrophoretic pattern obtained. The morphological aspects observed are in agreement with the function of this gland in queens, given that virgin queens use venom in battles for the dominance of the colony, a situation that occurs as soon as they emerge, while fertilized queens rarely use venom. (c) 2006 Elsevier Ltd. All rights reserved.

Ferritin in iron containing granules from the fat body of the honeybees Apis mellifera and Scaptotrigona postica

It is already known that the behaviour of the honeybee Apis mellifera is influenced by the Earth's magnetic field. Recently it has been proposed that iron-rich granules found inside the fat body cells of this honeybee had small magnetite crystals that were responsible for this behaviour. In the present work, we studied the iron containing granules from queens of two species of honeybees (A. mellifera and Scaptotrigona postica) by electron microscopy methods in order to clarify this point. The granules were found inside rough endoplasmic reticulum cisternae. Energy dispersive X-ray analysis of granules from A. mellifera showed the presence of iron, phosphorus and calcium. The same analysis performed on the granules of S. postica also indicated the presence of these elements along with the additional element magnesium. The granules of A. mellifera were composed of apoferritin-like particles in the periphery while in the core, clusters of organised particles resembling holoferritin were seen. The larger and more mineralised granules of S. postica presented structures resembling ferritin cores in the periphery, and smaller electron dense particles inside the bulk. Electron spectroscopic images of the granules from A. mellifera showed that iron, oxygen and phosphorus were co-localised in the ferritin-like deposits. These results indicate that the iron-rich granules of these honeybees are formed by accumulation of ferritin and its degraded forms together with elements present inside the rough endoplasmic reticulum, such as phosphorus, calcium and magnesium. It is suggested that the high level of phosphate in the milieu would prevent the crystallisation of iron oxides in these structures, making very unlikely their participation in magnetoreception mechanisms. They are most probably involved in iron homeostasis. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

HERITABILITY OF THE NUMBER OF OVARIOLES IN HONEY-BEE WORKERS (APIS-MELLIFERA L) (HYM, APIDAE)

Narrow and broad sense heritabilities (h(2)) of the number of ovarioles in Apis mellifera L. workers were estimated using two distinct data sets, based on groups of half (queens inseminated by several drones) and super-sisters (single drone insemination). The values found are in the usual range for economically important characters (0.25-0.38).

Induction of the split sting trait in Africanized Apis mellifera (Hymenoptera : Apidae) by cold treatment of pupae

Split sting is the name given to a nonfunctional honey bee sting characterized by lancets not attached to the stylet. It has appeared in a mutant line in Brazil, and has provoked interest as a possible means to reduce honey bee colony defensiveness. We induced this alteration in Africanized Apis mellifera L. workers and queens by maintaining pupae at 20 degrees C. In particular, we determined the pupal phase most susceptible to alterations in the sting caused by cold treatment, and we investigated whether this treatment also affected survival to the adult phase and wing morphology. The highest frequency of split sting was detected in workers treated at the pink-eyed pupal phase. The lowest frequency was observed in the bees treated at the oldest worker pupal phase studied (brown-eyed pupae with lightly pigmented cuticle). Both queen pupal phases tested (white and pink-eyed pupae) were equally sensitive and produced high percentages of adults with split sting. However, the 20 degrees C treatment of workers and queens, at the different pupal phases, resulted in high frequencies of adults with deformed wings. Also, fewer workers and queens treated at the earlier pupal stages reached adult emergence. There was also an arrest in developmental time, corresponding to the period of cold treatment.

Differentiation of the honey bee (Apis mellifera L.) antennal lobes during metamorphosis: a comparative study among castes and sexes

In insects the antennal lobes (AL) constitute the brain deutocerebrum. In bees they consist of two neuropil regions, each associated with one antenna, delimited by a layer of glial cells and somata of neurons. The neuropil is organized in distinct globular structures of dense synaptic axons coming from the olfactory organs of the antennae, known as glomeruli. In Apis mellifera, as in other eusocial species of bees, queens, workers, and drones perform different functions in the colony and consequently the organs associated with these functions undergo a differential development. In this paper we analyzed the structure and size of the differentiating AL of queens, workers, and drones during metamorphosis using light microscopy. During metamorphosis the neuropil enlarge and differentiates into concentric structures known as glomeruli. The results showed size, structural and temporal differences in the glomeruli development among the classes of individuals of the colony. The neuropil differentiation starts early and is faster in drones and newly emerged worker is the colony individual class with greater neuropil area in AL. These results are discussed taking in account the functions of the individuals in the colony. (C) Koninklijke Brill NV, Leiden, 2011.

Storaged products and presence of acid phosphatase in fat body cells at pre-pupal worker stage of Apis mellifera Linnaeus, 1758 (Hymenoptera, Apidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphological changes in the cephalic salivary glands of females and males of Apis mellifera and Scaptotrigona postica (Hymenoptera, Apidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)