Influence of virgin queen honeybees (Apis mellifera) on queen rearing and foraging

ABSTRACT. Virgin queens are as effective as mated laying queens at inhibiting colonies from rearing queens but not from producing queen cell cups. Colonies without brood produce fewer queen cell cups than similar colonies that have brood. Colonies without queens forage much less and collect less pollen than with either a mated or virgin queen. Colonies with virgin queens forage as much as those with mated queens but collected less pollen.     

Growth of Tiller Buds in Barley: Effects of Shade Treatment and Mineral Nutrition

Examination of the stem apex of Proctor barley showed that thebud of the coleoptile tiller, Tc, is probably present in thedry grain and that the bud, TI, carried in the axil of the firstleaf is present at or soon after 24 h from planting. Subsequentlytiller buds are initiated with a plastochron of about 4 days,this being rather longer than that for the foliar primordia.During the initial phase of bud growth vascular connectionsare established with the leaf above, but not to the subtendingleaf. At some time after these vascular connections are formedand when it has a dry weight of 4–7 µg the bud entersa phase of rapid, exponential growth in dry weight. Shading the first leaf delays the onset of rapid growth forboth Tc and Ti, but after a lag period rapid growth commences;this is coincident with development of the second leaf as anorgan exporting assimilated carbon. The phase of rapid growth of tiller buds is delayed when applicationof either nitrogenous or nonnitrogenous minerals is delayed.Ammonium was found to be less satisfactory as a nitrogen sourcethan nitrate, probably because of toxicity effects. Slight growthof Tc and T1 occurs in presence of nonnitrogenous minerals andabsence of nitrogen but growth is greater when nitrogen is suppliedin absence of the other minerals, although such growth is substantiallyless than that found when all nutrients are supplied. The interactionbetween nitrogen and non-nitrogenous minerals which controlsbud growth was not found to affect growth of the parent plantwhich is, as previously shown, controlled by timing of the nitrogensupply. AnotheT distinction is that higher concentrations ofnitrogen and the other minerals are required for maximum growthof the bud than for that of the plant. Tiller bud growth is interpreted as occurring in two phases.In the first, initiation, phase there is a close associationwith the subtending leaf, and nutritionally bud and leaf arelinked. This phase is followed by one in which the bud is directlyconnected by vascular traces to the leaf above, which becauseof this controls bud growth by modulating supply of assimilatedcarbon and nitrogen, and other minerals to it.     

The Active and the Inactive Form of the hAT1 Receptor Have an Identical Ligand-Binding Environment: An MPA Study on a Constitutively Active Angiotensin II Receptor Mutant

Several models of activation mechanisms were proposed for G protein-coupled receptors (GPCRs), yet no direct methods exist for their elucidation. The availability of constitutively active mutants has given an opportunity to study active receptor conformations within acceptable limits using models such as the angiotensin II type 1 (AT₁)¹ receptor mutant N111G-hAT₁ which displays an important constitutive activity. Recently, by using methionine proximity assay, we showed for the hAT₁ receptor that TMD III, VI, and VII form the ligand-binding pocket of the C-terminal amino acid of an antagonistic AngII analogue. In the present contribution, we investigated whether the same residues would also constitute the ligand-binding contacts in constitutively activated mutant (CAM) receptors. For this purpose, the same Met mutagenesis strategy was carried out on the N111G double mutants. Analysis of 43 receptors mutants in the N111G-hAT₁ series, photolabeled and CNBr digested, showed that there were only subtle structural changes between the wt-receptor and its constitutively active form.     

High rates of extra‐pair paternity in a socially monogamous beetle with biparental care

1. Nest construction and paternity assurance are predicted to favour biparental care in insects. The horned passalus (Odontotaenius disjunctus) is a socially monogamous beetle with biparental care that breeds in decaying logs. The genetic mating system of the horned passalus was investigated to determine if paternity assurance is likely to drive the evolution or maintenance of paternal care in this system. Parental time budgets were also examined to better understand the types and frequencies of behaviours performed by parents. 2. Genotyping‐by‐sequencing revealed high levels of extra‐pair paternity, with 54.8% of offspring sired by extra‐pair males and 70% of nests containing extra‐pair young. 3. More heterozygous social males were cuckolded less than more homozygous social males. Extra‐pair mating, however, seems unlikely to increase offspring genetic diversity as extra‐pair offspring were not more heterozygous than within‐pair offspring, and average brood heterozygosity did not increase with higher rates of extra‐pair paternity. 4. Behavioural observations demonstrated that parents spent on average 46.5% of their time processing the decaying wood resource for larval offspring. Because resource processing is a by‐product of feeding and provides shareable benefits for all larvae in the brood, this form of paternal care could be favoured despite low paternity.     

In the Arms of Africa: The Life of Colin Turnbull

In the Arms of Africa: The Life of Colin Turnbull. Roy Richard Grinker. Chicago: University of Chicago Press, 2002. 368 pp.     

The Development and Structure of the Root-nodules of Myrica gale L. with Special Reference to the Nature of the Endophyte

The development and structure of the root nodules of Myricagale are described, and evidence advanced showing that theyrepresent modified lateral roots. Attempts at the isolationof the endophyte were unsuccessful, but on the basis of a cytologicalstudy of the nodules the author adheres to the view of someprevious investigators that the endophyte is actinomycetal.