Suitable Cavities Research Articles

Characteristics of roost cavities used by Lilian's Lovebird Agapornis lilianae in Liwonde National Park, Malawi

Lilian's Lovebird Agapornis lilianae is a non-excavating cavity user of mopane Colophospermum mopane woodlands. We investigated roost characteristics of Lilian's Lovebirds in Liwonde National Park, Malawi. We quantified tree and roost site variables for roost and non-roost trees. Sixty-six roosts were found. Roosts were in large tall mopane trees with a mean diameter at breast height (dbh) of 57.4 ± 1.64 cm, a mean height of 16.5 ± 0.42 m, and with a mean cavity entrance height of 10.0 ± 0.05 m. Non-roost areas had significantly smaller trees (mean dbh = 39.4 ± 1.72 cm). Human disturbance was low in both areas, but browsing of African elephant Loxodonta africana was evident by large areas of stunted mopane woodland recorded in non-roost areas. We recommend that the current Liwonde National Park vegetation map be updated to highlight areas of stunted mopane woodland unsuitable for Lilian's Lovebird roosts. The impact of elephant browsing on large mopane trees should be assessed to understand its impact on the availability of suitable cavities for lovebirds and other tree cavity reliant vertebrate species.

Defining the complementarities between antibodies and haptens to refine our understanding and aid the prediction of a successful binding interaction.

BackgroundLow molecular weight haptens (<1000 Da) cannot be recognized by the immune system unless conjugated to larger carrier molecules. Antibodies to these exceptionally small antigens can still be generated with exquisite sensitivity. A detailed understanding at the molecular level of this incredible ability of antibodies to recognize haptens, is still limited compared to other antigen classes.MethodsDifferent hapten targets with a broad range of structural flexibility and polarity were conjugated to carrier proteins, and utilized in sheep immunization. Three antibody libraries were constructed and used as potential pools to isolate specific antibodies to each target. The isolated antibodies were analysed in term of CDR length, canonical structure, and binding site shape and electrostatic potential.ResultsThe simple, chemically naïve structure of squalane (SQA) was recognized with micromolar sensitivity. An increase in structural rigidity of the hydrophobic and cyclic coprostane (COP) did not improve this binding sensitivity beyond the micromolar range, whilst the polar etioporphyrin (POR) was detected with nanomolar sensitivity. Homoserine lactone (HSL) molecules, which combine molecular flexibility and polarity, generated super-sensitive (picomolar) interactions. To better understand this range of antibody-hapten interactions, analyses were extended to examine the binding loop canonical structures and CDR lengths of a series of anti-hapten clones. Analyses of the pre and post- selection (panning of the phage displayed libraries) sequences revealed more conserved sites (123) within the post-selection sequences, when compared to their pre-selection counterparts (28). The strong selection pressure, generated by panning against these haptens resulted in the isolation of antibodies with significant sequence conservation in the FW regions, and suitable binding site cavities, representing only a relatively small subset of the available full repertoire sequence and structural diversity. As part of this process, the important influence of CDR H2 on antigen binding was observed through its direct interaction with individual antigens and indirect impact on the orientation and the pocket shape, when combined with CDRs H3 and L3. The binding pockets also displayed electrostatic surfaces that were complementary to the hydrophobic nature of COP, SQA, and POR, and the negatively charged HSL.ConclusionsThe best binding antibodies have shown improved capacity to recognize these haptens by establishing complementary binding pockets in terms of size, shape, and electrostatic potential.

Modulation, asymmetry and the diurnal variation in axionic dark matter searches

In the present work we study possible time dependent effects in Axion Dark Matter searches employing resonant cavities. We find that the width of the resonance, which depends on the axion mean square velocity in the local frame, will show an annual variation due to the motion of the Earth around the sun (modulation). Furthermore, if the experiments become directional, employing suitable resonant cavities, one expects large asymmetries in the observed widths relative to the sun's direction of motion. Due to the rotation of the Earth around its axis, these asymmetries will manifest themselves as a diurnal variation in the observed width.

Raccoon (Procyon lotor) Diurnal Den use within an Intensively Managed Forest in Central West Virginia

Abstract Intensive forest management may influence the availability of suitable den sites for large den-seeking species, such as Procyon lotor (Raccoon). As part of a Raccoon ecology study on an industrial forest in the Allegheny Mountains of central West Virginia, we radio-tracked 32 Raccoons to 175 diurnal den sites to determine relative use of dens that included cavity trees, rock dens, log piles, slash piles, and exposed limbs. Patterns of den use significantly differed between sexes and among seasons. Overall, we recorded 58 cavity dens in 12 tree species with 7 maternal dens found in 5 tree species. Raccoons selected larger-diameter den trees than available cavity trees and non-cavity trees. Because the abundance of suitable tree cavities is known to influence Raccoon densities and recruitment at fine spatial scales and female Raccoons in this study used tree cavities as maternal den sites, the continued harvest of large-diameter trees (i.e., those capable of developing den cavities) without replace...

Species differences and geographic variation in the communal roosting behavior ofPrionostemmaharvestmen in Central American rainforests

Many species roost communally but the proximate causes and ultimate functions of this widespread behavior remain poorly understood. We studied the communal roosts of two undescribed species of harvestmen in the genus Prionostemma Pocock 1903 at a Caribbean rainforest site in southeastern Nicaragua. The species are quite similar in gross morphology but differ in body coloration, male genitalia, and roosting behavior. One species roosts primarily on spiny palms while the other species, which is darker in coloration, roosts inside buttress root cavities. In a mark-recapture study, the cavity-roosting species had higher levels of individual site fidelity than found previously in the spiny palm-roosting species, perhaps because suitable cavities are scarcer than spiny palms. The tree cavity aggregations were strongly male-biased, which our review of the literature suggests is unusual for harvestman roosts. The overall sex ratio of the spiny palm aggregations was 1∶1, but some roost sites were strongly male biased while others were strongly female biased. Removing all harvestmen from 10 spiny palm roost sites shifted the overall sex ratio toward males on subsequent days, but the sites with skewed sex ratios remained skewed in the same directions despite complete turnover in roost membership. These results are discussed in relation to mechanisms of roost formation and possible sex differences in vagility, microhabitat preferences and sensitivity to disturbance. Both species also occur at La Selva Biological Station in Costa Rica but neither forms roosting aggregations in spiny palms or tree cavities there. A possible explanation for the geographic variation is that roosting patterns change over time through cultural drift.

Ratiometric fluorescent probe based on novel red-emission BODIPY for determination of bovine serum albumin

A novel red-emission boron-dipyrromethene(BODIPY) dye with a pyrrole ring was synthesized simply via one-pot reaction. The spectral properties of it were investigated under the conditions of different solvents. The results show that the as-prepared BODIPY dye is extremely sensitive to solvent polarity, and the fluorescent emission enhances with the decrease of solvent polarity. In aqueous buffer, the addition of bovine serum albumin leads to a ratiometric change in absorption spectra with an association constant of 1.16×106 L/mol. Meanwhile, the fluorescence emission increases greatly at 622 nm but changes slightly at 575 nm. The response time is very short(less than 3 min), and the changes of color can be noticed by naked eyes. Bovine serum albumin can be detected by this ratiometric fluorescence probe, but other proteins or enzymes cannot be detected by this method, which indicates that this novel dye has high selectivity towards bovine serum albumin. The reason is that bovine serum albumin has suitable hydrophobic cavities for binding with the dye. In addition, the dye molecule can penetrate cell membrane easily and make a fast fluorescent stain, which makes it a potential probe for living-cell fluorescence imaging.

Hole Selection by Nesting Swifts in Medieval City-Walls of Central Spain

Disturbance and predation risks from terrestrial animals decline the higher up the nest sites selected by birds that nest in wall cavities are located. Terrestrial predators can also negate the protective quality of higher nesting sites by approaching from above in walls. It is unknown how terrestrial predation risks from below and above walls determine nest site selection in cavity-nesting species. In relation to this situation, we describe nest-site selection in common swifts Apus apus in the medieval city walls of Ávila, Spain. We recorded the entry size, hole depth and the horizontal and vertical positions of cavities. Most cavities were empty despite their size being suitable for nesting. Swifts nested in cavities at least 12 cm deep and with an entry between 3.5 cm and 13 cm wide. Nests were 3.5 m above the ground and 1.7 m below the top of the wall, although there were suitable cavities at the lower and higher extremes, respectively. Higher predation risks and disturbances could explain why suitable cavities were empty at lower and higher heights. The distances to the ground and to the top of the wall, as well as the distance to the nearest corner, accounted for about one-tenth of the probability that a cavity was used for nesting. Our data do not indicate a possible reason for nesting near corners, but weather is an obvious candidate.

Woodpecker excavations suitability for and occupancy by cavity users in the boreal mixedwood forest of eastern Canada

In the boreal forest, where tree cavities are mainly excavated by woodpeckers, many holes are incomplete excavations that are not suitable cavities for most other cavity users that form nest webs. We assessed cavity suitability for and use by a community of primary excavators and secondary users in managed and unmanaged landscapes in the boreal mixedwood forest of eastern Canada. We compared ground surveys of tree holes with direct inspections of the inside of potential cavities in remnant habitats surrounded by cutover areas and in large tracts of unharvested forest. We found that ground surveys overestimated suitable cavity abundance: only 38% of the potential cavities detected by ground surveys were suitable for nesting in both managed and unmanaged landscapes. Ground surveys of active nests correctly detected a greater proportion of primary (93%) than secondary cavity nesters (48%). In nest webs such as those of the boreal forest, where cavities are mainly created by woodpeckers, our results indicate that a large proportion of holes detected from the ground are not suitable for cavity nesters, thus overestimating the actual availability of nest sites. Furthermore, when nest cavities are active, ground surveys are satisfactory for detecting primary cavity nesters, but they are inadequate for detecting secondary cavity nesters.

Temporal and Spatial Factors Shaping Reproductive Performance in a Mediterranean Population of the Eurasian NuthatchSitta europaea

A Mediterranean population of the Eurasian nuthatch Sitta europaea using nestboxes was studied during three breeding seasons (2009-2011). The study area was a managed holm oak forest where suitable natural cavities for breeding were accordingly scarce. A large proportion of breeding territories was significantly associated with nestboxes located in the periphery of the patch and with large-holed nestboxes. The relationship between habitat heterogeneity (predicted by canopy cover of holm oaks and tree numbers) and breeding performance (egg-laying date, clutch size, hatching success, fledging success and breeding success) was tested. Egg-laying date was independent of predictors of habitat heterogeneity but was related to breeding success: earlier nesters achieved better breeding success than those breeding later. Clutch size and breeding success showed a negative relationship with canopy cover and tree numbers, respectively: both reproductive parameters were higher in the apparently suboptimal territories than in the optimal ones. These results are interpreted as an effect of the severe competition for cavities between all species breeding in the nestboxes and the reproductive output of nuthatch is density-dependent. The high overall breeding success achieved by nuthatches suggests that holm oak forest must be considered a high quality habitat for this species.

Habitat Selection and Reproductive Success of Lewis's Woodpecker (Melanerpes lewis) at Its Northern Limit

Lewis's Woodpecker (Melanerpes lewis) has experienced population declines in both Canada and the United States and in 2010 was assigned a national listing of threatened in Canada. We conducted a two-year study (2004–2005) of this species at its northern range limit, the South Okanagan Valley in British Columbia, Canada. Our main objective was to determine whether the habitat features that influenced nest-site selection also predicted nest success, or whether other factors (e.g. cavity dimensions, clutch initiation date or time of season) were more important. Nest tree decay class, density of suitable cavities and total basal area of large trees were the best predictors of nest-site selection, but these factors were unrelated to nesting success. Estimates of demographic parameters (mean ± SE) included daily nest survival rate (0.988±0.003, years combined), nest success (0.52±0.08), clutch size (5.00±0.14 eggs), female fledglings per successful nest (1.31±0.11), and annual productivity (0.68±0.12 female fledglings per nest per year). Although higher nest survival was associated with both early and late initiated clutches, early-initiated clutches allowed birds to gain the highest annual productivity as early clutches were larger. Nests in deep cavities with small entrances experienced lower predation risk especially during the peak period of nest predation. We concluded that nest-site selection can be predicted by a number of easily measured habitat variables, whereas nest success depended on complicated ecological interactions among nest predators, breeding behaviors, and cavity features. Thus, habitat-based conservation strategies should also consider ecological factors that may not be well predicted by habitat.

Assessing the effects of selective logging on birds in Neotropical piedmont and cloud montane forests

In tropical and subtropical forests there is limited information about how to integrate sustainable timber management with the conservation of biodiversity. We examined the effect of selective logging on the bird community to help develop management guidelines to assure the conservation of biodiversity in forests managed for timber production. The study design consisted of control and harvested plots in piedmont and cloud forests of the subtropical montane forests of the Andes in northwestern Argentina. We conducted bird point-count surveys combined with distance estimation. Breeding season bird community composition was more similar between control and logged forest in both the cloud forest and piedmont, than between the two elevations, probably because Neotropical bird communities change dramatically along elevational gradients. Within each elevation zone, community composition changed significantly between harvested and control forests. Both between and within each elevation zone no significant differences in bird density were detected. Similarly, when we analyzed bird density according to diet guilds no general pattern could be extracted. However, we found a significantly greater density of cavity nesters and lower of non-cavity nesters in control plots, probably because most trees that can develop suitable cavities were extracted in logged plots and these plots had a greater structural diversity enabling more nesting resources. Grouping species according to their nesting habitat requirements has rarely been used in the neotropics and other tropical and subtropical forests, but focusing management attention on cavity nesters might address the most sensitive portion of the avian community as well as other species dependent on trees likely to hold cavities.

Change in Density of Duck Nest Cavities at Forests in the North Central United States

AbstractDuring the past century, clear-cut hardwood forests of the north central United States have regenerated, and trees have matured into size classes increasingly capable of producing cavities suitable for nesting ducks. We determined the density of natural cavities suitable for cavity-nesting ducks, compared suitable cavity-tree distribution by size class and species, and assessed how forest maturation impacted suitable cavity density and distribution over time at four sites in the north central United States. During 2006–2008, cavities suitable for nesting ducks occurred at densities of 1.76, 1.40, 1.84, and 0.92/ha at Mingo National Wildlife Refuge (NWR) in Missouri, Shiawassee NWR in Michigan, Muscatatuck NWR in Indiana, and a study site including Mead State Wildlife Area in Wisconsin, respectively. Suitable nest-cavity densities increased at Mingo NWR (+300%) since 1965 and Shiawassee NWR (+900%) since 1973, but they remained similar at study sites examined during the mid-1980s (Muscatatuck NWR and Mead Wildlife Area) when previous site-specific cavity-suitability criteria were applied to our cavity data. Differences among sites were due to variation in tree species composition, stage of forest maturation, and potentially forest harvest regimes. Comparison of size distributions of all trees and those with suitable nest cavities indicated these forests have yet to mature into the most prolific cavity-producing size classes. Our findings suggest nest sites are not limiting duck populations at these four sites and hardwood forests with similar composition and structure. Rather than using the traditional practice of supplementing duck nest sites, wildlife managers in the North Central region should assess actual limiting factors before developing habitat management prescriptions for local cavity-nesting duck populations.

Responses to experimental reduction and increase of cavities by a secondary cavity-nesting bird community in cavity-rich Pyrenean oak forests

Cavity shortage limits secondary cavity-nesting birds (SCN) assemblages in intensively-managed forests with few cavities, but whether cavity availability limits SCN in cavity-rich forests remains unclear. To address this issue, we used a replicated before-after-control-impact design in which the availability of cavities was experimentally reduced and increased in cavity-rich Quercus pyrenaica forests. Cavity-blocking and nest-box addition led to reduction by 66% and increase by 185%, respectively, of nest densities of blue (Cyanistes caeruleus) and great (Parus major) tits. Analysis of cavity characteristics suggests that tits occupied less suitable cavities in blocking plots compared to control and nest-box addition plots after treatments, further indicating that the availability of suitable nest-sites may limit tit populations. No effect of cavity manipulation was found for short-toed treecreepers (Certhia brachydactyla) and Eurasian nuthatches (Sitta europaea), which defend larger territories than tits and whose numbers may be more influenced by territoriality than by nest-sites. Alternatively, high plasticity in nest-site use of treecreepers may enable them to cope with reductions in cavity availability and increased interspecific competition. Spotless starlings (Sturnus unicolor) were little affected by cavity manipulation. Often foraging on pastures, starlings may be more limited through reduced foraging opportunities in this forested landscape than by nest-sites. In addition, starlings may exclude other species from their preferred cavities to cope with reductions in numbers of suitable cavities. Community responses to the variation in cavity abundance in cavity-rich Pyrenean oak forests may therefore vary considerably among species, depending on their plasticity in nest-site use, behavioral dominance, foraging conditions or social structure. Thus, management actions aimed to increase cavity abundance and suitability for SCN communities in cavity-rich forests should consider inter-specific interactions and species-specific characteristics of the targeted species.

Nesting habitat of the Tucuman ParrotAmazona tucumanain an old-growth cloud-forest of Argentina

SummaryTucuman ParrotAmazona tucumanabreeds in the cloud-forest of south-eastern Bolivia and north-western Argentina (or Southern Yungas forest). We studied the nesting requirements of the Tucuman Parrot and assessed cavity availability, reuse, and spatial pattern of nests in El Rey National Park – one of the last mature, undisturbed areas of the Southern Yungas forest. We recorded 44 nesting attempts in seven tree species, with most nests (95%) being located in live canopy trees &gt; 60 cm DBH. Most parrot nest-cavities occurred inBlepharocalix salicifolius(60%) and cavities in this species were selected significantly more than expected based on availability. Nests were shallower and higher than nests of otherAmazonaspecies. For all years combined, mean nest density of Tucuman Parrot was 0.24 ± 0.04 nest ha-1and the distance to the nearest active nest was significantly greater than the distance between all trees used as nests. Nesting pairs of Tucuman Parrot were separated by 144.1 ± 152.8 m, while potential nest-trees were 66.0 ± 55.4 m apart. Density of suitable cavities for nesting was 4.6 cavities ha-1. Approximately 16 suitable cavities were available for each breeding pair (0.24 breeding pair ha-1and four suitable cavities ha-1) and 5% of the suitable cavities available were occupied, suggesting that suitable cavities are not a limiting resource. However, due to the territorial behaviour of breeding pairs, some of these cavities are unavailable to other breeding pairs. The spatial requirements of Tucuman Parrot for nesting could limit management actions intended to increase the density of nesting pairs.

The dilemma of selecting suitable proximal carious lesions in primary molars for restoration using ART technique.

To determine the examiner's accuracy in selecting proximal carious lesions in primary molars for restoration using the atraumatic restorative treatment (ART) approach. Intervention study. CLINICAL SETTING AND PARTICIPANTS: A total of 804 six to eight year-olds from 30 rural schools in Kenya participated in the study. Three examiners selected a total of 1,280 suitable proximal carious lesions in primary molars after examining 6,002 children from 30 schools randomly selected out of 142 schools in two divisions. Seven operators randomly paired on a daily basis with eight assistants restored the lesions. An explanation was provided for any cavity that was not restored. Pre-and post-operative radiographs of the cavities were also taken for evaluation. The examiner's choice of suitable proximal cavities restorable using the ART approach was related to the decision made to either restore or not during the operative stage. The radiographic findings of the selected cavities were also compared to the decision made by the operator. The results obtained were used to determine the examiner's accuracy in selecting suitable proximal cavities for restoration using the ART approach. The majority of the children recruited in the study were excluded due to absenteeism, pulpal-exposure or anxiety during the operative stage. Only 804 children received one restoration in their primary molars. The examiner's accuracy in selecting suitable ART-restorable cavities clinically was 94.9% and based on radiographic analysis was 91.7%. A trained and diligent examiner has a very good chance of selecting proximal carious lesions restorable with the use of ART approach, without the threat of dental pulpal-involvement during the excavation of caries.

Redefining tissue engineering for nanomedicine in ophthalmology

Working at the nanoscale means to completely rethink how to approach engineering in the body in general and in the eye in particular. In nanomedicine, tissue engineering is the ability to influence an environment either by adding, subtracting or manipulating that environment to allow it to be more conducive for its purpose. The goal is to function at the optimum state, or to return to that optimum state. Additive tissue engineering replaces cells or tissue, or tries to get something to grow that is no longer there. Arrestive tissue engineering tries to stop aberrant growth which, if left uncontrolled, would result in a decrease in function. Nano delivery of therapeutics can perform both additive and arrestive functions influencing the environment either way, depending on the targeting. By manipulating the environment at the nanoscale, the rate and distribution of healing can be controlled. It infers that potential applications of nanomedicine in ophthalmology include procedures, such as corneal endothelial cell transplantation, single retinal ganglion cell repair, check of retinal ganglion cell viability, building of nanofibre scaffolds, such as self-assembling peptides, to create a scaffold-like tissue-bridging structure to provide a framework for axonal regeneration in the case of optic nerve reconnection or eye transplantation, and ocular drug delivery. Examples of potential arrestive therapies include gene-related treatment modalities to inhibit intraocular neovascularization and to block retinal cell apoptosis. Looking towards the future, this review focuses on how nanoscale tissue engineering can be and is being used to influence that local environment.

Supply of tree-holes limits nest density of cavity-nesting birds in primary and logged subtropical Atlantic forest

Tree cavities are proposed to limit populations and structure communities of cavity-nesting birds. Although the greatest diversity of cavity-nesting birds is found in tropical and subtropical moist forests, little is known about how tropical logging affects the abundance of cavities or cavity-nesting birds. We compared the abundance of cavities and cavity nests between primary and selectively-logged subtropical moist Atlantic forest in Argentina, and conducted the first before-after controlled nest-box addition experiment to determine whether nest sites limit the breeding density of cavity-nesting birds in tropical or subtropical moist forest. Visual inspection of 86 cavities identified through ground-surveys revealed that only 19% were suitable for nesting birds, suggesting that cavity abundance may be overestimated in the literature on tropical forests. Suitable cavities were found in fewer than 1% of 1156 trees <60 cm dbh but 20% of 20 trees >100 cm dbh. Logged forest had half the basal area of primary forest, one third the density of large trees, nine times fewer cavities suitable for nesting birds, and 17 times fewer active nests. When we added nest boxes, nesting density increased on treatment plots but not on control plots in both logged and primary forest, suggesting that cavity supply can limit nest density even in relatively undisturbed forest. This is the first experiment to show how reduced cavity supply in logged tropical forest can limit breeding density of cavity-nesting birds. International initiatives such as forest certification should promote tropical timber management strategies that conserve large live cavity-bearing trees.

Selection of Nest Trees by Cavity-nesting Birds in the Neotropical Atlantic Forest

One of the five most important global biodiversity hotspots, the Neotropical Atlantic forest supports a diverse community of birds that nest in tree cavities. Cavitynesting birds may be particularly sensitive to forestry and agricultural practices that remove potential nest trees; however, there have been few efforts to determine what constitutes a potential nest tree in Neotropical forests. We aimed to determine the characteristics of trees and cavities used in nesting by excavators (species that excavate their own nest cavity) and secondary cavity-nesters (species that rely on existing cavities), and to identify the characteristics of trees most likely to contain suitable cavities in the Atlantic forest of Argentina. We used univariate analyses and conditional logistic regression models to compare characteristics of nest trees paired with unused trees found over three breeding seasons (2006‐2008). Excavators selected dead or unhealthy trees. Secondary cavity-nesters primarily selected cavities that were deep and high on the tree, using live and dead cavity-bearing trees in proportion to their availability. Nonexcavated cavities suitable for birds occurred primarily in live trees. They were most likely to develop in large-diameter trees, especially grapiaApuleia leiocarpaand trees in co-dominant or suppressed crown classes. To conserve cavity-nesting birds of the Atlantic forest, we recommend a combination of policies, economic assistance, environmental education, and technical support for forest managers and small-scale farmers, to maintain large healthy and unhealthy trees in commercial logging operations and on farms.

Nest‐Site Defense by Competing Honey Bee Swarms During House‐Hunting

AbstractCavity‐nesting animals must often defend their homes against intruders, especially when the availability of suitable cavities is limited. Competition for nest sites is particularly strong when multiple groups of the same species migrate synchronously to found a new home. This may be the case for honey bees during the reproductive season, because neighboring colonies often cast swarms simultaneously, leading to potential competition for high‐quality nesting cavities. To test the idea that honey bee swarms may compete for and defend potential nest sites as they search for a new home, we observed pairs of artificial swarms that were house‐hunting concurrently. Workers from one swarm in each pair carried a gene influencing body color, so that the bees from the two swarms were easily distinguished. We set up a high‐quality nest box and waited for nest‐site scouts from each swarm to explore and recruit swarm mates to it. We recorded all the interactions between competing scouts at the nest box and found that when scouts from both swarms explored the box simultaneously they behaved agonistically toward bees from the other swarm. The level of aggression depended on the number of scouts from each swarm present at the nest box. When only one to three scouts from each swarm were at the box, they rarely fought. But when the scouts from one swarm outnumbered those from the other swarm (4–20 vs. one to three bees), those in the majority advertised their presence with a buzzing behavior at the entrance opening, and started mobbing and killing those in the minority. When one swarm gained clear control of the nest box (20+ vs. zero to one bees), some of its scouts guarded the box’s entrance, preventing entry by foreign scouts. Our study exemplifies how cavity‐nesting animals may compete for and defend suitable nesting sites.

Imidazolium salts from amino acids—a new route to chiral zwitterionic carbene precursors?

Chiral, carboxylic acid-functionalised imidazolium zwitterions were synthesised from the corresponding l-amino acids phenyl alanine, alanine and glycine (achiral). They form infinite C 1 1 (10) chain structures in the solid state. The incorporation of water is dependent upon the creation of suitable cavities by the steric demands of the amino acid side chains.