Colony fissioning in honey bees: size and significance of the swarm fraction

During colony founding in honey bees, a portion of a colony’s workforce (the “swarm fraction”) departs with the old mother queen in a swarm while the remaining workforce stays with a new daughter queen in the parental nest. There is little quantitative information about swarm fraction size and about how swarm fraction size affects the growth and survival of mother-queen and daughter-queen colonies. We measured (a) the swarm fraction in naturally fissioning honey bee colonies, (b) the growth and survival of mother-queen colonies as a function of swarm size, and (c) the growth and survival of mother-queen and daughter-queen colonies as a function of the swarm fraction. We found an average swarm fraction of 0.75. We also found a significant positive effect of swarm size and swarm fraction on the growth (i.e., comb built, brood produced, food stored, and weight gained) and the survival of mother-queen colonies. We found no effect of swarm fraction on the survival of daughter-queen colonies. Evidently, a honey bee colony must devote a large majority of its workforce to a swarm so that the mother-queen colony can grow sufficiently rapidly to survive its first winter.     

Fixation patterns in simple choice reflect optimal information sampling

Simple choices (e.g., eating an apple vs. an orange) are made by integrating noisy evidence that is sampled over time and influenced by visual attention; as a result, fluctuations in visual attention can affect choices. But what determines what is fixated and when? To address this question, we model the decision process for simple choice as an information sampling problem, and approximate the optimal sampling policy. We find that it is optimal to sample from options whose value estimates are both high and uncertain. Furthermore, the optimal policy provides a reasonable account of fixations and choices in binary and trinary simple choice, as well as the differences between the two cases. Overall, the results show that the fixation process during simple choice is influenced dynamically by the value estimates computed during the decision process, in a manner consistent with optimal information sampling.     

The chromatin-remodeling protein BAF60/SWP73A regulates the plant immune receptor NLRs

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A study of sandfly species (Diptera: Psychodidae: Phlebotominae) in a focus of cutaneous leishmaniasis in the municipality of Baturité, Ceará, Brazil.

In a study on putative vectors of cutaneous leishmaniasis in Baturité, Ceará State, Brazil, six sandfly species were identified: Lutzomyia longipalpis, L. wellcomei, L. peresi, L. whitmani, L. shannoni and L. migonei. In general L. whitmani and L. migonei were the predominant species. They were collected in periodomiciliary areas and were attracted by man and equines. L. whitmani was the most anthropophilic species. Studies using animals as bait showed that blood-feeding occurs throughout the night. Previously L. whitmani had been found infected with a Leishmania species of the braziliensis complex and L. migonei was infected with peripylarian flagellates. In combination these findings suggest that they may be responsible for periodomestic transmission of cutaneous leishmaniasis.     

AhDGR2, an amaranth abiotic stress-induced DUF642 protein gene,modifies cell wall structure and composition and causes salt and ABA hyper-sensibility in transgenic Arabidopsis

Planta - An amaranth DGR gene, induced under abiotic stress, modifies cell wall structure and causes hypersensitivity to ABA and salt when overexpressed in Arabidopsis. DUF642 is a highly conserved...     

In vitro study of the insulin-like action of vanadyl-pyrone and -pyridinone complexes with a VO(O4) coordination mode

The insulin-like action of a novel class of potential insulin-mimetic complexes was investigated in terms of free fatty acid (FFA) release from isolated rat adipocytes. Vanadyl complexes such as VO(ema)2 [(bis(2-ethyl-3-hydroxy-4-pyrone)VO], VO(mpp)2 [bis (3-hydroxy-2-methyl-4(1H)-pyridinone)VO], VO(dmpp)2 [bis(1,2-dimethyl-3-hydroxy-4(1H)-pyridinone)VO] and VO(empp)2 [bis(2-ethyl-3-hydroxy-1-methyl-4(1H)-pyridinone)VO] were tested together with vanadyl sulfate for comparison. The inhibitory effect of the vanadium complexes on FFA release, from rat adipocytes treated with epinephrine, is dependent on concentration and for that reason the results are reported in terms of the IC50 value, the 50% inhibition concentration. The results show that all the complexes have an inhibitory effect on FFA release and that two pyridinone complexes, VO(mpp)2 and VO(empp)2, have a significantly better insulin-mimetic activity than that of vanadyl sulfate.