Adult Colonies Research Articles

Seasonal abundance and vertical distribution of siphonophores in western Norwegian fjords

Seasonal abundance of siphonophores in Korsfjord and Fanafjord was studied by net sampling. Nanomia cara, Lensia conoidea and Dimophyes arctica were dominant species present throughout the year. Abundance of N. cara colonies peaked in late May and early June. Low numbers of relatively large colonies and high numbers of siphonulae were observed during winter. Dimophyes arctica and L. conoidea had a generation shift in March, when large over-wintering and small young polygastric colonies co-existed briefly before the former disappeared. Abundances were lowest during winter, and eudoxids were consistently more numerous than polygastric colonies for both species. Maximum abundances of polygastric D. arctica and L. conoidea occurred in early May and late June, respectively. Lensia conoidea may have more than one annual generation in Korsfjord. Vertical distributions of siphonophores were studied with an remotely operated vehicle in nine fjords. The distributions of agalmatid physonects, probably mostly N. cara, differed significantly between the fjords, with the weighted mean depths of the distributions ranging from 99 to 412 m. Results from Sognefjord suggested diel vertical migration. The bulk of the adult colonies in each fjord occurred below sill depth. Siphonophores were not observed at localities known to host persistent populations of Periphylla periphylla.

Heart rate reflects osmostic stress levels in two introduced colonial ascidians Botryllus schlosseri and Botrylloides violaceus

The influence of abiotic factors on the establishment and success of invasive species is often difficult to determine for most marine ecosystems. However, examining this relationship is critical for predicting the spread of invasive species and predicting which habitats will be most vulnerable to invasion. Here we examine the mortality and physiological sensitivity to salinity of adult colonies of the colonial ascidians Botryllus schlosseri and Botrylloides violaceus. Adult colonies of each species were exposed to abrupt changes in salinity (5, 10, 15, 20, 25, 30 psu) in the laboratory. Salinity ranges used in the laboratory corresponded with those of the field distributions of B. violaceus and B. schlosseri in the Great Bay Estuary, NH. Heart rate was used as a proxy for health to assess the condition of individual colonies. Heart rates were monitored daily for approximately 2 weeks. Results revealed that both species experienced 100% mortality after 1 day at 5 psu and that their heart rates declined with decreasing salinity. Heart rates of B. schlosseri remained consistent between 15 and 30 psu and slowed at 10 psu. Heart rates of B. violaceus remained constant between 20 and 30 psu, but slowed at 15 psu. These laboratory results corresponded to the distribution of these species in estuaries, indicating salinity is a key factor in the distribution and dominance of B. schlosseri and B. violaceus among coastal and estuarine sites. Furthermore, physiological differences to salinity were found between colonies of B. schlosseri in the Venetian Lagoon and colonies in Portsmouth Harbor, suggesting adaptation to environmental variables.

Low intraspecific aggressiveness in two obligate plant-ant species

Little is known about the aggressiveness of plant-ants typically living in isolated trees nor about how that aggressiveness varies based on this isolation. Here, we examine intra- and interspecific aggressiveness between workers of two Allomerus species associated with two different myrmecophytes. In both cases, the level of intraspecific aggressiveness is very low whatever the distance separating the tested nests, while interspecific conflicts are always violent. Similar patterns of aggressiveness have been reported in various ant species, but the strictly arboreal life of Allomerus ants associated with the isolation of their adult colonies highlight different ecological conditions that might explain the lack of aggressiveness between conspecifics.

Effect of requeening on fall populations of honey bees on the northern Great Plains of North America

SummaryThe effects of requeening honey bee colonies in the last week of July with newly mated queens, mature queen cells, or supersedure cells, on sealed brood, adult worker bee populations and colony population demographics were assessed at twelve day intervals until early December. Requeening altered brood rearing patterns, adult worker bee populations and colony demographics. Requeened colonies contained populations with higher proportions of young bees. By early December, colony population sizes converged amongst treatments and were not statistically different.

Larval cannibalism and worker-induced separation of larvae in Hypoponera ants: a case of conflict over caste determination?

Reproductive altruism and cooperative brood care are key characteristics of eusocial insects and reasons for their ecological success. Yet, Hymenopteran societies are also the stage for a multitude of intracolonial conflicts. Recently, a conflict between adult and larval colony members over caste fate was described and evidence for overt conflict was uncovered in several bee species. In theory, diploid larvae of many Hymenopteran species should experience strong fitness benefits, if they would be able to change their developmental pathway towards the queen caste. However, larval self-determination potential is low in most advanced eusocial Hymenopterans, because workers often control larval food intake and queenworker caste dimorphisms are generally high. In the ant genus Hypoponera, larvae actively feed on food provided by workers and here we show extremely low queenworker size differences in these ants: the lowest in H. opacior, where fertile wingless (intermorphic) queens weigh on average only 13% more than workers. Thus, slightly better nutrition during development might change the fate of a Hypoponera larva from a completely sterile worker to a fertile queen. One possibility to obtain extra food for Hypoponera larvae with their well-developed mandibles would be to cannibalise adjacent larvae. Indeed, we observed frequently larval cannibalism in ant nests. Yet, adult workers apparently try to prohibit larval cannibalism by carefully separating larvae in the nest. Larvae, which were experimentally brought into close contact, were rapidly set apart. Workers further sorted larvae according to size and responded swiftly to decreasing food levels, by increasing inter-larval distance. Still, an experimental manipulation of the larval cannibalism rate in H. schauinslandi failed to provide conclusive evidence for the link between larval cannibalism and caste development. Hence, further experiments are needed to determine whether the widespread larval cannibalism in Hypoponera and the untypical brood distribution can be explained by an overt caste conflict.

Acquisition of symbiotic dinoflagellates (Symbiodinium) by juveniles of the coral Acropora longicyathus

Scleractinian corals may acquire Symbiodinium from their parents (vertically) or from the environment (horizontally). In the present study, adult colonies of the coral Acropora longicyathus from One Tree Island (OTI) on the southern Great Barrier Reef (Australia) acquired two distinct varieties of symbiotic dinoflagellates (Symbiodinium) from the environment. Adult colonies had either Symbiodinium from clade C (86.7%) or clade A (5.3%), or a mixture of both clades A and C (8.0% of all colonies). In contrast, all 10-day-old juveniles were associated with Symbiodinium from clade A, while 83-day-old colonies contained clades A, C and D even though they were growing at the same location. Symbiodinium from clade A were dominant in both 10- and 83-day-old juveniles (99 and 97% of all recruits, respectively), while clade D was also found in 31% of 83-day-old juveniles. Experimental manipulation also revealed that parental association (with clade A or C), or the location within the OTI reef, did not influence which clade of symbiont was acquired by juvenile corals. The differences between the genetic identity of populations of Symbiodinium resident in juveniles and adult A. longicyathus suggest that ontogenetic changes in the symbiosis may occur during the development of scleractinian corals. Whether or not these changes are due to host selective processes or differences in the physical environment associated with juvenile versus adult colonies remains to be determined.

CONTINUOUS, MIXED, AND ALTERNATING EXPOSURE TO DELTAMETHRIN AND FENTHION AFFECT DEVELOPMENT OF RESISTANCE IN CULEX PIPIENS PALLENS IN CHINA

A field population of Culex pipiens pallens was collected from Nanjing, China on July in 2000 and reared in an insectarium. Larvae were subjected to single, mixed, and alternating exposure to deltamethrin and/or fenthion, and the surviving early 4th instars were reared for establishment of adult colonies. Larvae from the colonies were then subjected to the same selection pressures over the subsequent 15 generations. Resistance rates and ratios were measured as LC50 values derived from larval bioassays. In populations exposed to deltamethrin or fenthion alone (single exposure), resistance levels rose rapidly. The LC50 values for deltamethrin and fenthion alone were 29.3 and 1.565 mg/liter, respectively, and the ratios of resistance were 697.6- and 24.8-fold, respectively. Exposure to a mixture of deltamethrin and fenthion (1:1; mixed selection) reduced the development of resistance. The LC50 value and ratio of resistance for the mixture of deltamethrin and fenthion were 0.607 mg/liter and 14.8-fold, respectively, at generation 15. Exposure to alternating treatments of deltamethrin and fenthion (alternating selection) showed an even lower development of resistance. For the alternating treatments, the LC50 value and ratio of resistance to deltamethrin were 0.795 mg/liter and 17.7-fold, respectively (generation 14), and those to fenthion were 0.219 mg/liter and 3.6-fold, respectively (generation 15). Together, these results indicate that the single continuous insecticide selection generated a much more severe resistance than a mixture and/or alternating treatments.

Ecological and phenological covariates of offspring sex ratio in barn swallows

Non-random sex allocation in relation to parental, ecological and phenological factors has been investigated in several correlational studies of birds, mostly based on few breeding seasons and relatively small sample sizes, which have led to different results. We investigated sex ratio of nestling barn swallows (Hirundo rustica) in relation to adult sex ratio, laying date, clutch size, colony size and meteorological conditions in a sample of 553 broods (>2200 nestlings) during 10 years. At the population level, nestling sex ratio varied among years and deviated from parity in two years. Sex ratio among adults did not predict offspring sex ratio in the current or the following year. At the within-family level, the proportion of sons increased with laying date in large clutches, did not vary among clutches of intermediate size, and tended to decline with laying date in small clutches. Large colonies harbored more sons. The proportion of males increased with temperature during laying whereas the effects of temperature during the pre- or post-laying periods and that of rainfall were non-significant. These patterns of variation of offspring sex ratio did not differ between years. Thus, we identified several potential causal sources of variation in barn swallow offspring sex ratio, including temporal, phenological and ecological factors. The observation of an association of offspring sex with temperature during laying is novel for birds and may be mediated by effects on maternal steroid hormones profile. The ecological and evolutionary implications of present findings are discussed in the light of adaptive sex allocation theory.

Substratum preferences in planula larvae of two species of scleractinian corals, Goniastrea retiformis and Stylaraea punctata

To test whether coral planulae recruit randomly to different coral reef habitats or have specific substratum preferences, the settling behavior of planulae from two shallow water coral species from Pago Bay, Guam (13°25.02N, 144°47.30E) were examined in the laboratory in June and July of 1995. Goniastrea retiformis is generally restricted to the shallow reef front (<10 m depth) in areas dominated by crustose coralline algae (CCA), while Stylaraea punctata is abundant on inner reef flats were CCA coverage is low and sand and carbonate rubble covered by biofilms is common. When presented with four substrata (1) carbonate rock scrubbed free of biofilm and dried as a control, (2) the CCA Hydrolithon reinboldii, (3) the CCA Peyssonelia sp., and (4) naturally conditioned carbonate rubble covered by a biofilm, G. retiformis larvae showed a significant preference for H. reinboldii, and S. punctata larvae for the carbonate biofilm treatment. The preference shown by S. punctata larvae for biofilmed surfaces did not diminish with increasing larval age up to 11 days. These results suggest that the larvae of both species are capable of habitat selection, and that the preferred substrata among those tested bears a relationship to the habitats in which adult colonies were found.

Immunohistochemical localization of a retinoic acid-like receptor in nerve cells of two colonial anthozoans (Cnidaria)

Retinoic acid is known to induce vertebrate stem cells to differentiate into a variety of cell types, including neurons. Although retinoic acid was reported to affect morphogenetic pattern specification in the hydrozoan Hydractinia (Müller, W.A., 1984. Retinoids and pattern formation in a hydroid. J. Embryol. Exp. Morph. 81, 253–271) and a retinoid RXR receptor was cloned in the jellyfish Tripedalia (Kostrouch, Z., Kostrouchova, M., Love, W., Jannini, E., Piatigorsky, J., Rall, J.E., 1998. Retinoic acid X receptor in the diploblast, Tripedalia cystophora. Proc. Natl. Acad. Sci. U.S.A. 95, 13442–13447), the cellular targets of retinoids were not investigated. We used Western immunoblotting and immunohistochemistry to investigate the presence and cellular distribution of a RXR-like receptor in the sea pansy Renilla koellikeri and in the staghorn coral Acropora millepora (Cnidaria, Anthozoa). Western blots revealed a 64 kDa protein from a sea pansy extract in a band that co-migrated with a RXR protein from the rat brain. Using antibodies raised against an epitope of human alpha RXR, we visualized putative ectodermal sensory cells in the polyp column of the adult sea pansy. Immunoreactivity was absent in staghorn coral larvae but present in the polyp column of adult colonies in the form of clusters of neuron-like cells in the basiectoderm near the ectoderm-mesoglea interface. These observations suggest that a RXR-like receptor is involved in epithelial nerve cell specification in adult anthozoans and that this role is conserved throughout evolution.

P104 Expression of notch receptors and their ligands in the adult human articular cartilage and colony forming cells

P104 Expression of notch receptors and their ligands in the adult human articular cartilage and colony forming cells

Ontogeny of a symbiont-produced chemical defense in Bugula neritina (Bryozoa)

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 327:183-191 (2006) - doi:10.3354/meps327183 Ontogeny of a symbiont-produced chemical defense in Bugula neritina (Bryozoa) Nicole B. Lopanik1,3,*, Nancy M. Targett1, Niels Lindquist2 1University of Delaware, Graduate College of Marine Studies, 700 Pilottown Road, Lewes, Delaware 19958, USA 2University of North Carolina at Chapel Hill, Institute of Marine Sciences, 3431 Arendell Street, Morehead City, North Carolina 28557, USA 3Present address: University of Michigan, Life Sciences Institute, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109-2216, USA *Email: nlopanik@umich.edu ABSTRACT: The larvae of the arborescent bryozoan Bugula neritina are chemically defended against predators by unpalatable secondary metabolites called bryostatins. Bryostatins, polyketide-derived secondary compounds, are produced by the bacterial symbiont ‘Candidatus Endobugula sertula’, which is present throughout all life stages of B. neritina. Crude extracts of larval and all juvenile stages of B. neritina significantly reduced pinfish feeding (p < 0.003). Extract unpalatability is due to high bryostatin concentrations. As B. neritina increases in age after larval settlement and metamorphosis, palatability increases as bryostatin concentrations decrease precipitously. Extracts of brooding portions of adult colonies reduced pinfish feeding by a significant 54% (p = 0.008), whereas extracts of non-brooding portions of the same colonies resulted in a non-significant 20% decline in feeding (p = 0.125). Our data suggest that the different life stages of B. neritina employ alternate defensive strategies. The mobile, short-lived larvae and early-stage juveniles are defended from predators by having deterrent levels of bryostatins; in contrast, the older juveniles and adults, which are clonal and relatively long-lived, may be defended largely by high levels of structural material (i.e. chitin and carbonate). Predation pressure on the vulnerable larval stage of B. neritina appears in part to have driven selection for the development and maintenance of the symbiotic relationship between B. neritina and Ca. Endobugula sertula whereby the larvae are chemically defended by symbiont-produced bryostatins. KEY WORDS: Chemical defense · Symbiosis · Bugula neritina · Bryostatins · Ontogenetic defense Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 327. Online publication date: December 07, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.

Microbial community associated with the colonial ascidian Cystodytes dellechiajei

The ascidian Cystodytes dellechiajei (Della Valle, 1877) (phylum Chordata, class Ascidiacea, family Polycitoridae) is a colonial tunicate that inhabits benthic rock environments in the Atlantic, Pacific and Indian Oceans, as well as the Mediterranean Sea. Its life cycle has two phases, the adult sessile colony and the free-living larva. Both adult zooids and larvae are surrounded by a protective tunic that contains several eukaryotic cell lines, is composed mainly of acidic mucopolysacharides associated with collagen and elastin-like proteins, and is covered by a thin cuticle. The microbiota associated with the tunic tissues of adult colonies and larva of C. dellechiajei has been examined by optical, confocal and electron microscopy and by fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), and 16S rRNA gene clone library analysis. Microscopy analyses indicated the presence inside the tunic, both for the adult and the larva, of a dense community of Bacteria while only the external surface of colony cuticle was colonized by diatoms, rodophyte algae and prokaryotic-like epiphytes. Transmission electron microscopy showed tunic eukaryotic cells that were engulfing and lysing bacteria. 16S rRNA gene analyses (DGGE and clone libraries) and FISH indicated that the community inside the tunic tissues of the adults and larvae was dominated by Alphaproteobacteria. Bacteria belonging to the phyla Gammaproteobacteria and Bacteroidetes were also detected in the adults. Many of the 16S rRNA gene sequences in the tunic tissues were related to known aerobic anoxygenic phototrophs (AAP), like Roseobacter sp. and Erythrobacter sp. In order to check whether the gene pufM, coding for the M subunit of the reaction centre complex of aerobic anoxygenic photosynthesis, was being expressed inside the ascidian tissues, two libraries, one for an adult colony and one for larva, of cDNA from the expressed pufM gene were also constructed. The sequences most frequently (64% for colony and 67% for larva) retrieved from these libraries presented > 90% aa identity with the pufM gene product of the Roseobacter-like group, a cluster of AAP widely detected in marine planktonic environments.

Population dynamics and conservation biology of the over-exploited Mediterranean red coral

The main goal of ecologists is nowadays to foster habitat and species conservation. Life-history tables and Leslie–Lewis transition matrices of population growth can be powerful tools suitable for the study of age-structured over harvested and/or endangered species dynamics. Red coral ( Corallium rubrum L 1758) is a modular anthozoan endemic to the Mediterranean Sea. This slow growing, long lived species has been harvested since ancient times. In the last decades harvesting pressure increased and the overall Mediterranean yield reduced by 2 3 . Moreover, mass mortality (putatively-linked to global warming) recently affected some coastal populations of this species. Red coral populations are discrete genetic units, gonochoric, composed by several overlapping generations and provided of a discrete (annual) reproduction. A population of this precious octocoral was studied in detail and its static life table was compiled. In order to simulate the trends overtime of the population under different environmental conditions and fishing pressures, a discrete, non-linear model, based on Leslie–Lewis transition matrix, was applied to the demographic data. In this model a bell-shaped curve, based on experimental data, representing the dependence of recruitment on adult colonies density was included. On these bases the stability of the population under different density, reproduction and mortality figures was analysed and simulations of the population trends overtime were set out. Some simulations were also carried out applying to the studied population the mortality values measured during the anomalous mass mortality event which really affected some red coral populations in 1999. The population under study showed high stability and a strong resilience capability, surviving to a 61% reduction of density, to a 27.7% reduction of reproduction rate and to an unselective harvesting affecting 95% of the reproductive colonies.

Colony formation of C57BL/6J mice in visible burrow system: Identification of eusocial behaviors in a background strain for genetic animal models of autism

Deficits in social interaction are primary characteristics of autism, which has strong genetic components. Genetically manipulated mouse models may provide a useful research tool to advance the investigation of genes associated with autism. To identify these genes using mouse models, behavioral assays for social relationships in the background strains must be developed. The present study examined colony formation in groups of one male and three female mice (Experiment 1) and, groups of three male mice (Experiment 2) of the C57BL/6J strain in a semi-natural visible burrow system. For adult mixed-sex colonies, 4-h observations during both the dark and light cycles for 15 days demonstrated day-dependent increases in huddling together in the chamber accompanied by decreased frequencies of active social behaviors. Sequential analyses of social interactions indicated that approaches to the back of the approached animal typically elicited flight, while approaches to the front of the approached animal failed to do so. This was seen for female to female, and for female to male approaches, as well as male to female approaches, strongly counterindicating a view that rear approach/flight specifically reflects female responsivirity to unwanted male sexual approach. For adult male colonies, similar protocols found that these social behaviors were similar to those of adult mixed-sex colonies. These findings suggest two potentially useful measures of eusocial behavior in mice, of possible value for genetic mouse models of autism; that is, huddling together and approaches to the front but not the back, of conspecifics.

White Eye Color Mutant in &lt;I&gt;Haematobia irritans&lt;/I&gt; (Diptera: Muscidae)

The wild-type eye color of the horn fly, Hematobia iritans (L.) (Diptera: Muscidae), is a dark reddish brown. An apparent spontaneous mutation in a single adult colony fly resulted in a white-eyed mutant. A colony of white-eyed horn flies was established from this single individual and has been maintained in the laboratory. Laboratory crosses determined that the white-eyed phenotype is inherited as a simple Mendelian autosomal recessive with complete penetrance. No other differences from the wild-type flies were detected in the external characteristics of the mutant phenotype or in egg viability. However, white-eyed flies had significantly lower amounts of the pigment dihydroxyxanthommatin in their heads, suggesting either the lack of xanthommatin production, or a failure of transport and storage within the head of the mutant phenotype.

Colony genetic structure in a facultatively eusocial hover wasp

The degree of genetic heterogeneity among the individuals in an animal society depends on the society's genetic structure. Genetic heterogeneity, in turn, means that group members will differ in their reproductive objectives and conflicts over reproduction may arise. The resolution of these conflicts may be reflected in the way that reproduction is partitioned between potential reproductives. We used 5 microsatellite loci to investigate genetic structure and reproductive skew in 17 nests of the Malaysian hover wasp, Parischnogaster alternata. Parischnogaster alternata colonies are small (1?10 females), and all adult colony members are capable of mating and producing offspring. We found that colonies tended to consist of closely related individuals and that at any one time the production of both female and male offspring was nearly always monopolized by a single dominant female, despite considerable variation between nests in parameters predicted to affect skew. Subordinate females that remained in their natal colonies obtained indirect fitness benefits by helping to raise offspring to which they were related. Subordinate females also appeared to be positioned within an age-based queue for inheritance of the dominant egg-laying position. We suggest that the high skew in P. alternata may result from strong ecological constraints on solitary nesting, high relatedness, and a relatively high probability that subordinates will eventually inherit the position of dominance.

Retrospective Study on the Energy Requirements of Adult Colony Cats1–3

Retrospective Study on the Energy Requirements of Adult Colony Cats1–3

CDNA cloning and phylogenetic and expression analyses of actin in symbiotic dinoflagellates (Symbiodinium spp.)

Three cDNAs encoding actins were identified in two culturable strains (clades A and F) of the symbiotic dinoflagellates Symbiodinium spp. In a molecular phylogenetic analysis these actin sequences formed a monophyletic group with known dinoflagellate actins, remote from Syact-p that had been isolated from a clade A Symbiodinium strain (HG39). One of the newly identified actin sequences (SyAct-F1) was the most closely related to partial actin cDNA sequences (named AGfact-p and AFcact-p) isolated from adult colonies of two reef corals (Galaxea fascicularis and Favites chinensis) that were inhabited by Symbiodinium spp., suggesting the possibility that the latter two were from the symbionts. Partial AFcact-p sequences could be amplified by PCR using genomic DNA prepared from a symbiotic adult colony of F. chinensis as the template, but not from planula larvae in which zooxanthellae could not be detected, also arguing for the origin of AFcact-p in the symbiont. An expression analysis showed that the levels of the SyAct-A1 mRNA were comparable in symbiotic and non-symbiotic states, and also in motile and non-motile phases in a cultured condition, suggesting its usefulness as a constitutively expressed control gene in expression analysis of Symbiodinium mRNAs.

Influence of contrasting larval developmental types upon the population-genetic structure of cheilostome bryozoans

For many sedentary or sessile benthic marine invertebrates the planktonic duration of the larval stage is believed to be a key determinant of the magnitude of genetic differences between populations. An obvious dichotomy in dispersal potential exists within cheilostome bryozoans that develop from either (1) a cyphonautes larva that spends several weeks in the plankton or (2) a brooded coronate larva that settles soon after release from the adult colony. This study characterises the pattern of variation at allozyme loci among British populations of four species of bryozoan—two species with cyphonautes and two with coronate larvae. There is some variation in the estimates of genetic differentiation among similarly separated populations that may be a consequence of non-equilibrium genetic conditions arising from sporadic migration, possibly through dispersal by rafting on macroalgae by mature colonies. Despite this, however, both the level of genetic differentiation between populations and the pattern of migrant exchange correlate with the larval developmental mode. Bryozoan species that brood coronate larvae show higher levels of genetic heterogeneity between populations and significant isolation by distance genetic structure while, by contrast, distance has little or no effect upon the amount of genetic differentiation among populations of bryozoans with cyphonautes larvae. For cheilostome bryozoans, therefore, it appears that genetic differentiation between populations is directly associated with the type of larval development. These data are discussed also with respect to levels of gene diversity and the geological pattern of cheilostome bryozoan species diversity.