Time memory in social insects with a special focus on honey bees.

The ability to associate time and location with food sources is an evolutionary advantage for foraging animals. We find highly sophisticated time memory capabilities especially in social insects, which require efficient foraging capabilities for colony provisioning. Honey bees are perfectly suitable to study time memory mechanisms: they possess an elaborated time memory combined with a relatively simple neuronal clock network and a smaller gene set compared with the mouse model organism.

Dopey proteins are essential but overlooked regulators of membrane trafficking.

Dopey family proteins play crucial roles in diverse processes from morphogenesis to neural function and are conserved from yeast to mammals. Understanding the mechanisms behind these critical functions could have major clinical significance, as dysregulation of Dopey proteins has been linked to the cognitive defects in Down syndrome, as well as neurological diseases. Dopey proteins form a complex with the non-essential GEF-like protein Mon2 and an essential lipid flippase from the P4-ATPase family.

The pigment-dispersing factor neuronal network systematically grows in developing honey bees.

The neuropeptide pigment-dispersing factor (PDF) plays a prominent role in the circadian clock of many insects including honey bees. In the honey bee brain, PDF is expressed in about 15 clock neurons per hemisphere that lie between the central brain and the optic lobes. As in other insects, the bee PDF neurons form wide arborizations in the brain, but certain differences are evident.

Antibodies Against the Clock Proteins Period and Cryptochrome Reveal the Neuronal Organization of the Circadian Clock in the Pea Aphid.

Circadian clocks prepare the organism to cyclic environmental changes in light, temperature, or food availability. Here, we characterized the master clock in the brain of a strongly photoperiodic insect, the aphid , immunohistochemically with antibodies against Period (PER), Cryptochrome (CRY1), and crab Pigment-Dispersing Hormone (PDH). The latter antibody detects all so far known PDHs and PDFs (Pigment-Dispersing Factors), which play a dominant role in the circadian system of many arthropods.

Model and Non-model Insects in Chronobiology.

The fruit fly is an established model organism in chronobiology, because genetic manipulation and breeding in the laboratory are easy. The circadian clock neuroanatomy in is one of the best-known clock networks in insects and basic circadian behavior has been characterized in detail in this insect. Another model in chronobiology is the honey bee , of which diurnal foraging behavior has been described already in the early twentieth century.

Post-embryonic Development of the Circadian Clock Seems to Correlate With Social Life Style in Bees.

Social life style can influence many aspects of an animal's daily life, but it has not yet been clarified, whether development of the circadian clock in social and solitary living bees differs. In a comparative study, with the social honey bee, , and the solitary mason bee, , we now found indications for a differentially timed clock development in social and solitary bees. Newly emerged solitary bees showed rhythmic locomotion right away and the number of neurons in the brain that produce the clock component pigment-dispersing factor (PDF) did not change during aging of the adult solitary bee.

Loss of the Major Phosphatidylserine or Phosphatidylethanolamine Flippases Differentially Affect Phagocytosis.

The lipids phosphatidylserine (PtdSer) and phosphatidylethanolamine (PtdEth) are normally asymmetrically localized to the cytosolic face of membrane bilayers, but can both be externalized during diverse biological processes, including cell division, cell fusion, and cell death. Externalized lipids in the plasma membrane are recognized by lipid-binding proteins to regulate the clearance of cell corpses and other cell debris. However, it is unclear whether PtdSer and PtdEth contribute in similar or distinct ways to these processes.

A Functional Clock Within the Main Morning and Evening Neurons of Is Not Sufficient for Wild-Type Locomotor Activity Under Changing Day Length.

A major challenge for all organisms that live in temperate and subpolar regions is to adapt physiology and activity to different photoperiods. A long-standing model assumes that there are morning (M) and evening (E) oscillators with different photoreceptive properties that couple to dawn and dusk, respectively, and by this way adjust activity to the different photoperiods. In the fruit fly , M and E oscillators have been localized to specific circadian clock neurons in the brain.

The circadian clock uses different environmental time cues to synchronize emergence and locomotion of the solitary bee Osmia bicornis.

Life on earth adapted to the daily reoccurring changes in environment by evolving an endogenous circadian clock. Although the circadian clock has a crucial impact on survival and behavior of solitary bees, many aspects of solitary bee clock mechanisms remain unknown. Our study is the first to show that the circadian clock governs emergence in Osmia bicornis, a bee species which overwinters as adult inside its cocoon.

Degron-tagged reporters probe membrane topology and enable the specific labelling of membrane-wrapped structures.

Visualization of specific organelles in tissues over background fluorescence can be challenging, especially when reporters localize to multiple structures. Instead of trying to identify proteins enriched in specific membrane-wrapped structures, we use a selective degradation approach to remove reporters from the cytoplasm or nucleus of C. elegans embryos and mammalian cells.

Extracellular vesicle budding is inhibited by redundant regulators of TAT-5 flippase localization and phospholipid asymmetry.

Cells release extracellular vesicles (EVs) that mediate intercellular communication and repair damaged membranes. Despite the pleiotropic functions of EVs in vitro, their in vivo function is debated, largely because it is unclear how to induce or inhibit their formation. In particular, the mechanisms of EV release by plasma membrane budding or ectocytosis are poorly understood.

Pigment-Dispersing Factor-expressing neurons convey circadian information in the honey bee brain.

Pigment-Dispersing Factor (PDF) is an important neuropeptide in the brain circadian network of and other insects, but its role in bees in which the circadian clock influences complex behaviour is not well understood. We combined high-resolution neuroanatomical characterizations, quantification of PDF levels over the day and brain injections of synthetic PDF peptide to study the role of PDF in the honey bee We show that PDF co-localizes with the clock protein Period (PER) in a cluster of laterally located neurons and that the widespread arborizations of these PER/PDF neurons are in close vicinity to other PER-positive cells (neurons and glia). PDF-immunostaining intensity oscillates in a diurnal and circadian manner with possible influences for age or worker task on synchrony of oscillations in different brain areas.

A damping circadian clock drives weak oscillations in metabolism and locomotor activity of aphids (Acyrthosiphon pisum).

Timing seasonal events, like reproduction or diapause, is crucial for the survival of many species. Global change causes phenologies worldwide to shift, which requires a mechanistic explanation of seasonal time measurement. Day length (photoperiod) is a reliable indicator of winter arrival, but it remains unclear how exactly species measure day length.

Mechanisms and functions of extracellular vesicle release in vivo-What we can learn from flies and worms.

Cells from bacteria to man release extracellular vesicles (EVs) that contain signaling molecules like proteins, lipids, and nucleic acids. The content, formation, and signaling roles of these conserved vesicles are diverse, but the physiological relevance of EV signaling in vivo is still debated. Studies in classical genetic model organisms like C.

A new device for monitoring individual activity rhythms of honey bees reveals critical effects of the social environment on behavior.

Chronobiological studies of individual activity rhythms in social insects can be constrained by the artificial isolation of individuals from their social context. We present a new experimental set-up that simultaneously measures the temperature rhythm in a queen-less but brood raising mini colony and the walking activity rhythms of singly kept honey bees that have indirect social contact with it. Our approach enables monitoring of individual bees in the social context of a mini colony under controlled laboratory conditions.

Pea Aphids (Hemiptera: Aphididae) Have Diurnal Rhythms When Raised Independently of a Host Plant.

Seasonal timing is assumed to involve the circadian clock, an endogenous mechanism to track time and measure day length. Some debate persists, however, and aphids were among the first organisms for which circadian clock involvement was questioned. Inferences about links to phenology are problematic, as the clock itself is little investigated in aphids.

The single fgf receptor gene in the beetle Tribolium castaneum codes for two isoforms that integrate FGF8- and Branchless-dependent signals.

The precise regulation of cell-cell communication by numerous signal-transduction pathways is fundamental for many different processes during embryonic development. One important signalling pathway is the evolutionary conserved fibroblast-growth-factor (FGF)-pathway that controls processes like cell migration, axis specification and mesoderm formation in vertebrate and invertebrate animals. In the model insect Drosophila, the FGF ligand / receptor combinations of FGF8 (Pyramus and Thisbe) / Heartless (Htl) and Branchless (Bnl) / Breathless (Btl) are required for the migration of mesodermal cells and for the formation of the tracheal network respectively with both the receptors functioning independently of each other.