Colonies Of Origin Research Articles

Selective enrichment of founding reproductive microbiomes allows extensive vertical transmission in a fungus-farming termite.

Mutualistic coevolution can be mediated by vertical transmission of symbionts between host generations. Termites host complex gut bacterial communities with evolutionary histories indicative of mixed-mode transmission. Here, we document that vertical transmission of gut bacterial strains is congruent across parent to offspring colonies in four pedigrees of the fungus-farming termite Macrotermes natalensis. We show that 44% of the offspring colony microbiome, including more than 80 bacterial genera and pedigree-specific strains, are consistently inherited. We go on to demonstrate that this is achieved because colony-founding reproductives are selectively enriched with a set of non-random, environmentally sensitive and termite-specific gut microbes from their colonies of origin. These symbionts transfer to offspring colony workers with high fidelity, after which priority effects appear to influence the composition of the establishing microbiome. Termite reproductives thus secure transmission of complex communities of specific, co-evolved microbes that are critical to their offspring colonies. Extensive yet imperfect inheritance implies that the maturing colony benefits from acquiring environmental microbes to complement combinations of termite, fungus and vertically transmitted microbes; a mode of transmission that is emerging as a prevailing strategy for hosts to assemble complex adaptive microbiomes.

High-resolution (mtDNA) melting analysis for simple and efficient characterization of Africanized honey bee Apis mellifera (Hymenoptera:Apidae).

Analysis of the mtDNA variation in Apis mellifera L. has allowed distinguishing subspecies and evolutionary lineages by means of different molecular methods; from RFLP, to PCR-RFLP and direct sequencing. Likewise, geometric morphometrics (GM) has been used to distinguish Africanized honey bees with a high degree of consistency with studies using molecular information. High-resolution fusion analysis (HRM) allows one to quickly identify sequence polymorphisms by comparing DNA melting curves in short amplicons generated by real-time PCR (qPCR). The objective of this work was to implement the HRM technique in the diagnosis of Africanization of colonies of A. mellifera from Argentina, using GM as a validation method. DNA was extracted from 60A. mellifera colonies for mitotype identification. Samples were initially analyzed by HRM, through qPCRs of two regions (485bp/385bp) of the mitochondrial cytochrome b gene (cytb). This technique was then optimizing to amplify a smaller PCR product (207bp) for the HRM diagnosis for the Africanization of colonies. Of the 60 colony samples analyzed, 41 were classified as colonies of European origin whereas 19 revealed African origin. All the samples classified by HRM were correctly validated by GM, demonstrating that this technique could be implemented for a rapid identification of African mitotypes in Apis mellifera samples.

Defensive Behavior and Morphometric Variation in Apis mellifera Colonies From Two Different Agro-Ecological Zones of North-Western Argentina

European lineages of Apis mellifera were first introduced into America for beekeeping purposes. A subsequent introduction and accidental release of A. m. scutellata resulted in hybridization events that gave rise to Africanized populations that rapidly spread throughout the continent. In Argentina, Africanized honey bees (AHBs) have been mostly detected in northern regions of the territory, and represent a valuable genetic resource for the selection of stocks with advantageous characteristics for beekeeping. The objective of the present study was to profile honey bee colonies of wild origin with potential beneficial traits for apiculture using morphological, molecular and behavioral traits. Honey bee colonies chosen for evaluation were located in two different agro-ecological regions in north-western Argentina (Tucumán province): The Chaco Depressed Plain (Leales apiary) and the Piedmont (Famaillá apiary). Each apiary was surveyed three times during the 2017–2018 season (mid-season, wintertime, and early spring) for: brood population, phoretic Varroa level and defensive behavior (run, fly, sting, and hang). At the midpoint of the beekeeping season colonies were also characterized by morphometry (45 variables) and mitochondrial haplotypes (COI–COII intergenic region). Apiaries studied showed similar patterns throughout the beekeeping season, for most of the characteristics monitored. However, significant variation in defensive behavior parameters was found between apiaries at the different times of evaluation. Twelve of 45 morphometric variables also showed significant differences between apiaries. The mitochondrial haplotype analysis revealed a high representation of African A4 and A1 haplotypes (91%) in both apiaries. Haplotype variation was associated with morphometric and behavioral traits. Multivariate analyses [principal component analysis (PCA) and principal coordinate analysis (PCoA)] including morphometric and behavior variables explained 65.3% (PCA) and 48.1% (PCoA) of the variability observed between colonies in the first two components. Several morphometric parameters and “fly” behavior were mainly associated with the separation of the colonies. The results from this study point to a possible association between morphometric and behavioral variation and the adaptation of honey bee colonies to differential agro-ecological conditions. We discuss how the detected variation between apiaries can be used for the selection and preservation of honey bee ecotypes in regional breeding programs.

Influence of inbreeding in the early stages of artificially reared colonies of Bombus terrestris

AbstractIn the present study on the bumblebee Bombus terrestris, we investigated the influence of inbreeding on queen fitness by comparing diapause survival and egg‐laying success of queens mated with nestmate and non‐nestmate males. We then compared the early stage of colonies with or without diploid males and analysed colony characteristics to identify a factor predictive of colony outcome. Diapause survival was no different between queens mated with nestmates and non‐nestmates, but in the latter case, egg‐laying success was significantly higher. Queens mated with nestmates gave rise to a percentage of diploid male colonies (52.6%) compatible with brother–sister coupling. We obtained 18.6% of colonies with diploid males even from queens mated with non‐nestmates, indicating that the colonies of origin were in some way related or homozygous at the sex determination loci. There was no difference in the early growth stage between colonies with or without diploid males, except in the number of workers emerging in the first brood, which was significantly higher in the latter. Among diploid male colonies, the number of workers and the male/worker ratio in the first brood was highly variable and was not a good predictor of subsequent colony growth. Out of 49 colonies with diploid males that reached full development, only 11 had a sufficient size to assume that they could survive in the field or, in a commercial breeding, to be suitable for pollination purposes.

Development of a microbially-derived therapy against Fusobacterium nucleatum, a bacterial pathogen linked with colorectal cancer

Background. Specific bacterial species have been linked to several intestinal diseases, including colorectal cancer (CRC). In recent years, high abundances of an emerging pathogen, Fusobacterium nucleatum, have been identified in tumors and stool samples of CRC patients and it has been suggested that F. nucleatum contributes to CRC initiation and development. The possibility of suppressing the growth of F. nucleatum in the GI tract using antimicrobial-producing probiotic bacteria may reduce the overall risk of CRC development. Methods. Here, we screen a collection of faecal samples from healthy donors against F. nucleatum in an effort to discover an antimicrobial-producing isolate capable of selectively inhibiting this emerging human pathogen. Potential isolates with anti-Fusobacterial activity were then further analysed for the ability to inhibit the pathogen in cell culture and in a faecal fermentation system, which simulates the dynamic conditions of the human colon. Results. Culture-based screening of over 16,000 colonies of gastrointestinal origin resulted in the identification of one faecal isolate with probiotic potential displaying significant antagonistic activity against F. nucleatum initially in cell culture media and subsequently inhibition was confirmed in the simulated intestinal model. Conclusion. This study reveals that, a novel gut isolate demonstrates inhibition against the CRC-associated F. nucleatum in vitro and suppresses its growth in a model of the human distal colon. This is an important finding, suggesting the potential of a natural gut bacterium to supress the growth of a bacterial pathogen associated with CRC, which may contribute to reducing the overall risk of developing the disease.

Investigation of polyandry in honey bees (Apis mellifera) using microsatellites

Polyandry is a specific phenomenon increasing genetic diversity. To analyze the level of polyandry and to assess the contribution of drones to the genetic diversity of honey bee colonies, three microsatellite loci (A008, Ap049, and AC117) were studied in honey bees from colonies of different origin (Middle Russian race, Carpathian race, and hybrids) in Tomsk Province. The share of the introduced paternal alleles varied between colonies from 6.67 to 28.00%. The highest genetic diversity was observed in hybrid colonies (25–28% of introduced paternal alleles).

Use of wildlife rehabilitation centres in pathogen surveillance: A case study in white storks (Ciconia ciconia)

More than 70% of new human pathogens are zoonotic and many originate from the wildlife reservoir. Wildlife rehabilitation centres (WRC) are an easily accessible source for sample and data collection for preventive surveillance, but data collected this way may be biased. We use white storks (Ciconia ciconia) as a model to compare pathogen prevalence obtained in the field and WRC. We address factors that may affect disease prevalence data like origin, the age group and the “diseased” state of WRC admissions. In this study we compared prevalence of Escherichia coli and Salmonella spp. in the digestive tract; antibodies against West Nile virus, avian influenza and Newcastle disease virus, and antimicrobial resistance patterns of E. coli between nestling and adult wild storks established in different habitats (n=90) and storks admitted to two different WRC (n=30) in the same region.When age groups and colonies of origin were disregarded, the mean enterobacteria (E. coli, Salmonella) and viral antibody prevalence of the wild population (n=90) were similar to prevalence observed in the individuals admitted to WRC (n=30). However, in fledgling juvenile storks admitted to WRC, the prevalence of Salmonella spp. (13.3%), E. coli showing resistance to cefotaxime (37.9%) and against two antimicrobials at once (41.4%) were more similar to the prevalence in stork nestlings from landfill-associated colonies (7.9%, 37.1% and 48.6%, respectively for prevalence of Salmonella spp. and E. coli displaying, cefotaxime resistance and resistance against two antimicrobials), and significantly higher than in colonies located in natural habitats (0%; 10.5% and 15.8%, respectively).Thus, pathogen surveillance in individuals from an abundant species admitted to WRC is useful to monitor overall mean prevalence, but for certain pathogens may not be sufficient to detect differences between local populations. In addition, the ecology of the tested species and the specific temporal, spatial and age group distribution of WRC admissions have to be taken into account.

Swarming, defensive and hygienic behaviour in honey bee colonies of different genetic origin in a pan-European experiment

SummaryHoney bee colonies exhibit a wide range of variation in their behaviour, depending on their genetic origin and environmental factors. The COLOSS Genotype-Environment Interactions Experiment gave us the opportunity to investigate the phenotypic expression of the swarming, defensive and hygienic behaviour of 16 genotypes from five different honey bee subspecies in various environmental conditions. In 2010 and 2011, a total of 621 colonies were monitored and tested according to a standard protocol for estimation of expression of these three behavioural traits. The factors: year, genotype, location, origin (local vs. non-local) and season (only for hygienic behaviour) were considered in statistical analyses to estimate their effect on expression of these behaviours. The general outcome of our study is that genotype and location have a significant effect on the analysed traits. For all characters, the variability among locations was higher than the variability among genotypes. We also detected significant variability between the genotypes from different subspecies, generally confirming their known characteristics, although great variability within subspecies was noticed. Defensive and swarming behaviour were each positively correlated across the two years, confirming genetic control of these characters. Defensive behaviour was lower in colonies of local origin, and was negatively correlated with hygienic behaviour. Hygienic behaviour was strongly influenced by the season in which the test was performed. The results from our study demonstrate that there is great behavioural variation among different subspecies and strains. Sustainable protection of local genotypes can be promoted by combining conservation efforts with selection and breeding to improve the appreciation by beekeepers of native stock.

Linking at-sea mortality of a pelagic shearwater to breeding colonies of origin using biogeochemical markers

An emerging issue in seabird conservation is the ability to link at-sea mortality with observed demographic changes at breeding colonies. Applications of modelling and biochemical markers can be used to assign mortalities of unknown provenance to a colony of origin ensuring conservation actions are targeted at those colonies identified as the most affected. We analysed feathers (n = 120) from flesh-footed shearwater Puffinus carneipes collected from 5 breeding colonies throughout their range. Using stable isotopes (δ15N and δ13C) and trace element concentrations (Mn, Ni, Cu, Mo, Ag, Ba, Pb), we assigned birds recovered from fishing vessels off Australia, New Zealand, and the North Pacific to colony of origin, and investigated the rate of correct assignment at 3 spatial scales. Using quadratic discriminant analysis, samples of known origin were correctly assigned to basin, region, and breeding colonies at similar rates (92.3, 81.3, and 88.1%, respectively). Stable isotopes succeeded in assigning individuals among basins (72.8%), performing less well at the region and colony level (52.5 and 36.4%, respectively). In contrast, correct assignment was consistent at all 3 scales using only trace elements (93.2, 95.7, and 96.6%, respectively). Applying our final model based on trace elements to 116 flesh-footed shearwaters taken as bycatch in eastern Australia (n = 30), Western Australia (n = 32), New Zealand (n = 16), eastern North Pacific (n = 27) and western North Pacific (n = 11), we assigned individuals to colonies in New Zealand (35.3%), Western/South Australia (36.2%), Western Australia (27.6%), and Lord Howe Island (0.9%). Bycatch in fisheries may help explain ongoing declines in fleshfooted shearwater populations across the species’ range, highlighting the utility of assignment tools to account for unobservable mortality of wildlife at-sea.

Tractable field metrics for restoration and recovery monitoring of staghorn coral Acropora cervicornis

The staghorn coral Acropora cervicornis is a branching coral with complex morphol- ogy. While this structural complexity confers high ecological and habitat value, it hinders accurate quantification. An appropriate and quantitative coral 'unit' is required to effectively implement protective provisions (e.g. prevention of take or strategies to meet quantitative recovery criteria) for A. cervicornis under the United States Endangered Species Act. Actual measurements of 3- dimensional structure or extent of branches within colonies are time-consuming and therefore not feasible for monitoring application. This study calibrated arduous in-water measurements of total linear extent (TLE, sum of all branch lengths in a fully live colony, intuitively representing the 'amount' of coral in an individual colony) to more manageable standard field measurements of colony dimensions or photographs. The robustness of this relationship was then evaluated among colonies of different origin (wild, nursery-reared, transplanted) and different habitats (patch reef, shallow forereef, deep forereef) in the upper Florida Keys, USA. Within this sample set, colony vol- ume (calculated as an ellipsoid based on 3 colony dimensions) was highly predictive of TLE (r 2 = 0.94 for log-log linear regression), and this relationship was consistent for colonies from different origins and different reef habitats. Thus, 'unit' coral abundance at the colony scale in terms of branch extent (TLE) can be reliably estimated from simple colony dimensions in the Florida Keys. Additional data are required to determine if different calibrations are needed in other populations, to adjust estimates for partial mortality of colonies, and to 'scale up' reliable estimates to thicket- or reef-scale.

Population genetics study of common (Pipistrellus pipistrellus) and soprano (Pipistrellus pygmaeus) pipistrelle bats from central Europe suggests interspecific hybridization

The discovery that the most widespread bat in Europe comprises cryptic species, Pipistrellus pipistrellus (Schreber, 1774) (common pipistrelle) and Pipistrellus pygmaeus (Leach, 1825) (soprano pipistrelle), provides a great opportunity to look at the mechanism of species coexistence. Based on eight nuclear microsatellite loci (n = 353), we observed similarities between the species in Poland with respect to heterozygosity, allelic richness, mean relatedness, and inbreeding coefficients. However, pronounced differences in migratory patterns (shown by assignment tests) suggest that P. pygmaeus is the more migratory species. The proportion of bats migrating between colonies differed significantly, with 17.1% and 41.8% individuals of P. pygmaeus and P. pipistrellus, respectively, confidently assigned to colonies of origin. Both species demonstrated a more migratory character in central Europe compared with the populations from the British Isles. Given the cryptic nature of the examined taxa, we also assessed whether they hybridize. Hybridization was confirmed by three methods—one based on genetic distance and two based on Bayesian approaches. The overall hybridization rate, depending on assumed threshold values, ranged from 1.7% to 13.3% for both species. We conclude that the population structuring in these pipistrelles is not homogenous across their range. Moreover, hybridization between them in continental Europe does occur and is not rare.

Mating, ovariole number and sperm production of the dengue vector mosquito Aedes aegypti (L.) in Australia: broad thermal optima provide the capacity for survival in a changing climate

Little is known about mating, ovariole number and sperm production of Aedes aegypti (L.) in Australia, especially in relation to climate. To determine the extent of interpopulation variation and thermal dependence of reproductive traits in A. aegypti, laboratory studies are conducted using colonies originating from up to four locations in Queensland, Australia. Observations of insemination reveal that these behaviours are temperature‐dependent, although humidity levels appear to have little effect, with only small increases in insemination at higher humidities. No noteworthy variations in thermal optima (temperature ranges within which maximal performance occurs) for such behaviours are observed between colonies, with all showing high levels of insemination between 25 and 35 °C. Both male and female maximum fecundity for A. aegypti are also found to be temperature‐dependent. Sperm counts, not hitherto obtained for Australian A. aegypti, range from approximately 3000–5000 per male, with counts increasing with increased rearing and holding temperature, despite a decreasing body size. Conversely, ovary size decreases with temperature and body size, from approximately 100 ovarioles per female at 17 °C, to 85 at 35 °C. The lack of variation in reproductive capacity between colonies of different geographical origin indicates that any locally‐acting selective pressures are not driving divergence in key reproductive traits such as insemination ability and fecundity. This may be because the source populations used are not from sufficiently diverse climates. Nonetheless, the broad thermal optima for reproductive traits in A. aegypti are suggestive of limitations on these traits not being responsible for limiting distribution and population growth in the event of projected mean temperature rises.

Longevity and lifetime reproductive success of barn swallow offspring are predicted by their hatching date and phenotypic quality

1. Longevity is a major determinant of individual differences in Darwinian fitness. Several studies have analyzed the stochastic, time-dependent causes of variation in longevity, but little information exists from free-ranging animal populations on the effects that environmental conditions and phenotype early in ontogeny have on duration of life. 2. In this long-term (1993-2011) study of a migratory, colonial, passerine bird, the barn swallow (Hirundo rustica), we analyzed longevity and, in a subsample of individuals, lifetime reproductive success (LRS) of the offspring that reached sexual maturity in relation to hatching date, which can affect the rearing environment through a seasonal deterioration in ecological conditions. Moreover, we analyzed the consequences of variation in body size and, for the first time in any species, of a major component of immunity on longevity, both by looking at absolute phenotypic values and at deviations from the brood mean. 3. Accelerated failure time models showed that individuals of both sexes that hatched early in any breeding season enjoyed larger longevity and larger LRS, indicating directional selection for early breeding. Both male and female offspring with large T cell-mediated immune response relative to their siblings and female nestlings that dominated the brood size/age hierarchy had larger longevity than their siblings of inferior phenotypic quality/age. Conversely, absolute phenotypic values did not predict longevity. 4. Frailty modelling disclosed marked spatial heterogeneity in longevity among colonies of origin, again stressing the impact of rearing conditions on longevity. 5. This study therefore reinforces the notion that perinatal environment and maternal decisions over timing and site of breeding, and position in the brood hierarchy can have marked effects on progeny life history that extend well into adulthood. In addition, it provides the first evidence from any bird population in the wild that immune response when nestlings predicts individuals' longevity after sexual maturation.

Haematopoietic stem cells derived from sheep and human amniotic fluid engraft after transplantation

IntroductionMouse amniotic fluid c-Kit(+)/Lin(-) stem (AFS) cells display hematopoietic potential. We explored the haematopoietic potential of sheep and human AFS cells after in utero stem cell transplantation.MethodsHuman AFS cells (hAFSC)...

Individual variability of salivary gland proteins in three Phlebotomus species

Pooled salivary gland samples are frequently used to ensure the sufficient amount of material for the experiments; however, this could mask an individual variability. Thus, we compared salivary protein profiles in seven colonies of three Phlebotomus species: Phlebotomus sergenti, Phlebotomus perniciosus, and Phlebotomus papatasi. Surprisingly, the individual profiles differed significantly between the colonies as well as between individuals. The highest variability was observed in proteins with molecular masses of 42–46kDa corresponding to the yellow-related proteins. The phenogram constructed from salivary gland profiles revealed the existence of two main groups in P. sergenti, corresponding well with the geographical origin. The F1 progeny obtained from cross-mating studies between P. sergenti colonies of different geographical origin formed a distinct subgroup within the parental groups. In P. papatasi, several groups of protein profiles were observed with no relationship to the geographical origin. The biological role of salivary proteins variability is discussed.

Nosema ceranae in age cohorts of the western honey bee (Apis mellifera)

Nosemaceranae intensity (mean spores per bee) and prevalence (proportion of bees infected in a sample) were analyzed in honey bees of known ages. Sealed brood combs from five colonies were removed, emerging bees were marked with paint, released back into their colonies of origin, and collected as recently emerged (0–3days old), as house bees (8–11days old), and as foragers (22–25days old). Fifty bees from each of the five colonies were processed individually at each collection date for the intensity and prevalence of N. ceranae infection. Using PCR and specific primers to differentiate Nosema species, N. ceranae was found to be the only species present during the experiment. At each collection age (recent emergence, house, forager) an additional sample from the inner hive cover (background bees=BG) of each colony was collected to compare the N. ceranae results of this sampling method, commonly used for Nosema spore quantification, to the samples comprised of marked bees of known ages. No recently emerged bees exhibited infection with N. ceranae. One house bee out of the 250 individuals analyzed (prevalence=0.4%) tested positive for N. ceranae, at an infection level of 3.35×106spores. Infection levels were not statistically different between the recently emerged (mean=0 spores/bee) and house bees (mean=1.34×104spores/bee) (P=0.99). Foragers exhibited the highest prevalence (8.3%) and infection intensity (mean=2.38×106spores/bee), with a range of 0–8.72×107spores in individual bees. The average infection level across all foragers was significantly higher than that of recently emerged bees (P=0.01) and house bees (P=0.01). Finally, the prevalence of Nosema in infected bees was found to be positively correlated with the infection intensity in the sample.

Employing a highly fragmented, weedy coral species in reef restoration

A major determinant in reef restoration programs is the choice of species employed. In this paper, we concentrate on the potential use of Montipora digitata (Dana, 1846), a highly fragmented and weedy coral species, for reef restoration and for recreation of reef physiognomy in Bolinao, The Philippines, under the ‘gardening concept’. Coral ramets ( n = 1960) were reared in a shallow lagoon nursery for 1 year and then, the resulting nursery-grown colonies were transplanted onto denuded reef knolls at two different sites and according to three transplantation designs (grid design with high or low density and patch design). The nursery grown ramets, which had initially exhibited a 99% survivorship, were reduced to 87% by a super typhoon. Low detachment rates, low mortality (<1% both) and low bleaching (<3% over most months), have been indicating good nursery conditions for corals. Monitoring transplanted colonies for over 15 months showed no significant differences between the sites or among the three different transplantation designs. The major events of mortality and detachment were documented during the first 3 months post-transplantation and in the wake of a bleaching event. M. digitata transplants exhibited rapid growth (a 384% increase in ecological volume) and frequent fragmentation. Some fragments remained by their colonies of origin entangled in the attached branches, while other fragments fell onto the surrounding sandy substrate, forming M. digitata ‘beds’ around the knolls. In both, nursery and transplanted corals, creation of complex 3D structures was followed by recruitment of juvenile fishes into aggregations. Above results reveal that employing fast growing, weedy and easily fragmenting branching species, which are also considered as ‘modifier species’, in reef restoration may result in a fast regeneration of reef physiognomy. Instead of ‘copying’ natural processes, reef managers should therefore concentrate on recovering the reef's ability for self-maintenance.

Nestmate Recognition and the Role of Cuticular Hydrocarbons in the African Termite Raiding Ant Pachycondyla analis

Cuticular hydrocarbons (CHCs) are used for chemical communication among nestmates in many ant species, and they may play a role in the discrimination of nestmates and non-nestmates. Using the mandible opening response (MOR) bioassay, we tested the response of the African termite raiding ant, Pachycondyla analis, to CHC extracts of nestmates and non-nestmates. The ants were able to distinguish control chemical cues, from nestmate CHCs, and from non-nestmate CHCs, and, based on a CHC recognition threshold, aggression was demonstrated toward non-nestmates. Gas chromatography (GC) and GC-mass spectrometric analyses showed that CHC components of different ant colonies had chain lengths ranging from C(8) to C(31), comprising mainly n-alkanes, alkenes, and methyl branched alkanes, with the n-alkanes occurring in the same proportions among all colonies. The ants were grouped successfully according to their colonies of origin by using discriminant analysis of CHCs. We demonstrate that nestmate recognition occurs in P. analis, and that some of the cues involved are evidently alkenes and methyl-branched alkanes.

Inheritance of Resistance to &lt;I&gt;Acarapis woodi&lt;/I&gt; (Acari: Tarsonemidae) in Crosses Between Selected Resistant Russian and Selected Susceptible U.S. Honey Bees (Hymenoptera: Apidae)

The pattern of inheritance of tracheal mite resistance in selected Russian bees was determined in bioassays and in samples from field colonies. Resistant colonies of Russian origin and colonies selected for high susceptibility in the United States were used to generate divergent parental populations. Seven groups of F1 colonies were produced by crossing queens and drones from these selected resistant Russian and selected susceptible populations. In a series of bioassays with young workers exposed in infested colonies, average mite abundance (female mites per worker) in F1 colonies was intermediate (1.04 +/- 0.13 [mean +/- SE]) and significantly different from that of both resistant Russian (0.74 +/- 0.13) and selected susceptible (1.57 +/- 0.13) colonies. Colonies representing the three populations were established in two apiaries in July 2005. Colonies surviving with original queens after 10 mo had mite prevalences supporting the findings of the bioassay. All three resistant colonies had undetectable mite levels, whereas prevalences in four F1 colonies ranged from 0 to 53%, and in 10 susceptible colonies ranged from 0 to 90%. Tracheal mite resistance in Russian bees is likely polygenic, but there may be a number of genes with major dominance interacting with minor genes. Use of selected Russian queens mated with Russian drones or with drones from unknown sources is beneficial for beekeeping in areas with persistent problems with tracheal mite infestation.

Describing dispersal under habitat constraints: A randomization approach in lesser kestrels

Animal dispersal is usually studied with capture-mark-reencounter data, which provide information on realized dispersal but rarely on underlying processes. In this context, the unreliable assumption of all habitat being available is usually made when describing and analysing dispersal patterns. However, actual settlement options may be constrained by the spatial distribution of appropriate patches, so an important task to understand movement patterns is to adequately describe dispersal when the dispersers’ options are constrained by the sites that are available to them. Using a long-term monitored population of the migratory lesser kestrel, we show how randomization procedures can be used to describe dispersal strategies in such situations. This species breeds colonially in discrete patches, most individuals (83%) disperse from their natal colony, and dispersers tend to move short distances (median=7.2 km). Observed patterns (natal dispersal rates and median dispersal distances of birds emigrating from their natal colony) were compared with those expected from two null models of random settlement of individuals: in any colony available in the whole population, or within the subpopulation (cluster of colonies) of origin. Our simulations indicate that philopatry to the natal colony was much higher than expected under both null expectations, and observed distances were much lower than expected in the whole population. When individuals were constrained to settle within their natal subpopulation in the simulations, dispersal distances were longer than expected in females, but were higher or lower in males depending on year. Dispersal was not only constrained by the spatial distribution of settlement options, but specific hypotheses arise that can be helpful to design and conduct further research. These results challenge previous interpretations of observed dispersal patterns, which may not reflect free decisions of individuals but environmental or social constraints. We suggest using simulation procedures as a routine to advance in the understanding of dispersal ecology and evolution. Die Ausbreitung von Tieren wird normalerweise über Fang-Wiederfang-Daten untersucht, die zwar Informationen über die tatsächliche Ausbreitung liefern, jedoch wenig über die zugrundeliegenden Prozesse aussagen. In diesem Zusammenhang wird normalerweise die unwahrscheinliche Annahme getroffen, dass sämtliche Habitate zur Verfügung stehen, wenn Ausbreitungsmuster beschrieben und analysiert werden. Die tatsächlichen Ansiedlungsmgölichkeiten sind jedoch durch die räumliche Anordnung geeigneter Flächen beschränkt. Für das Verständnis der Bewegungsmuster ist es daher eine wichtige Voraussetzung, die Ausbreitung adäquat zu beschreiben, wenn die Ausbreitungsmöglichkeiten durch die zur Verfügung stehenden Flächen beschränkt sind. Unter Nutzung einer langfristig untersuchten Population des ziehenden Rötelfalkens beschreiben wir, wie Randomisierungsprozeduren genutzt werden können, um die Ausbreitungsstrategien in solchen Situationen zu beschreiben. Die Art brütet in Kolonien an diskreten Orten, die meisten Individuen (83 %) verlassen die Brutkolonie und die wandernden Vögel bewegen sich nur eine kurze Distanz (Median = 7,2 km). Die beobachteten Muster (Ausbreitungsraten und die Mediane der Ausbreitungsdistanzen von Vögeln, die ihre Geburtskolonie verlassen) wurden mit denen verglichen, die aufgrund von zwei Null-Modellen bei zufälligen Besiedlungen durch die Individuen erwartet wurden: in jede Kolonie, die in der Population zur Verfügung steht, oder innerhalb der Herkunfts-Subpopulation (ein Cluster von Kolonien). Unsere Simulationen weisen darauf hin, dass die Standorttreue in den Geburtskolonien viel höher war als aufgrund beider Null-Modelle erwartet wurde und dass die beobachteten Distanzen in der gesamten Population sehr viel geringer als erwartet waren. Wenn die Individuen in dem Modell darauf beschränkt waren, in der Herkunfts-Subpopulation zu siedeln, dann waren die Ausbreitungsdistanzen größer als erwartet bei den Weibchen, jedoch in Abhängigkeit vom Jahr bei den Männchen größer oder geringer. Die Ausbreitung war nicht nur durch die räumliche Verteilung der Ansiedlungsmöglichkeiten begrenzt, aber es ergeben sich spezifische Hypothesen, die hilfreich bei der Planung und Durchführung weiterer Forschung sind. Diese Ergebnisse stellen vorangegangene Interpretationen der beobachteten Ausbreitungsmuster in Frage, die nicht freie Entscheidungen von Individuen widerspiegeln, sondern soziale oder Umwelteinschränkungen. Wir schlagen vor, Simulationsprozeduren als Routine zu nutzen, um das Verständnis der Ausbreitungsökologie und Evolution zu fördern.