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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of fish diseases 27 (2004), S. 0 
    ISSN: 1365-2761
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Along the eastern seaboard of the US, Atlantic menhaden, Brevoortia tyrannus, develop characteristic ulcerative lesions, a condition termed ulcerative mycosis. These lesions are identical to those seen across Asia in fish affected by epizootic ulcerative syndrome, a condition caused by the fungus-like oomycete Aphanomyces invadans. Young-of-the-year menhaden inhabiting estuarine environments are the primary species affected in the USA and little is known about the factors involved in the initiation of the lesions, or why menhaden are predominantly infected. Atlantic menhaden, hogchoker, Trinectus maculatus, striped killifish, Fundulus majalis, and mummichog, Fundulus heteroclitus, were inoculated with A. invadans (80 zoospores per fish) to explore species differences in infection and lesion development. All four species developed lesions. Killifish developed frank lesions similar to those observed in menhaden but the gross lesions occurred later, approximately 5–10 days after those on menhaden. Hogchoker and mummichog did not develop gross skin ulcers; rather, their lesions appeared as reddened areas under the epidermis. Mummichogs also showed evidence of significant healing with a well-developed granuloma and significant myocyte regeneration. These experiments show that species barriers as well as ecological barriers can explain some of the factors involved in the development of lesions in, and specificity of the water mould for, menhaden.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1420-9098
    Keywords: Key words: Biomass, foundress survival, Pogonomyrmex barbatus, P.rugosus, respiration, worker production, brood production.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: A three-factor laboratory experiment (2 species × 2 soil types × 4 moisture levels) demonstrated that water is the most important factor effecting colony establishment and growth in the two ecologically equivalent sister species of desert seed-harvester ants Pogonomyrmex rugosus and P. barbatus. All experimental indices, percent gyne survival, gyne live wet mass, percent of gynes producing workers, and mean number of individuals (workers, larvae, and pupae), increased from low to moderate moistures and then levelled off. Soil texture also displayed a significant effect as gyne wet mass was 5 - 10% higher across treatments in soils that had a higher clay content. The only species effect was that P. barbatus gynes were smaller but produced more workers and brood than those of P. rugosus. That P. rugosus survives longer under arid conditions was demonstrated by a significantly higher number of nests with live workers in the driest treatment; number of live gynes displayed a similar pattern but differences were not significant. Additionally, P. barbatus produced fewer workers than P. rugosus in the driest treatment, while this number was higher than P. rugosus at all other moisture levels. Metabolic rate was higher and workers eclosed sooner in P. barbatus compared to the larger P. rugosus.
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  • 3
    ISSN: 1420-9098
    Keywords: Interspecific trail following ; workerless inquiline ant ; Pogonomyrmex colei ; reproductive biology ; seed-harvester ants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Pogonomyrmex colei is a workerless inquiline ant known only from nests ofP. rugosus, its closest relative. Ten of 776 (1.3%) host nests were parasitized at a site in central Arizona, while none of 1499 potential host colonies were parasitized at two other locales. Colonies ofP. colei are perennial, and host alate females in 9 of 10 colonies demonstrates that host queens survive parasitism. Three of 10 colonies died over 19 colony years of observation, while only 1 of 601 colonies became newly parasitized. Mating occurs in morning for up to 2–3 days following summer and fall rains and in afternoon during cool fall days. Mating is intranidal just outside the nest entrance, with males returning to the natal nest. MaleP. colei may be flightless because their wing area is reduced compared to host males. Females fly from the nest and locate potential host colonies by following trunk trails. Workers are the largest barrier to nest establishment, as they removed over 90% ofP. colei females placed in trunk trails or that entered host nests. Males and females ofP. colei andP. anergismus, the only other congeneric inquiline species, are diminutive compared to their hosts, with females 30% lighter than host workers. Fat content is lower and water content is higher inP. colei andP. anergismus females than in their hosts.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Insectes sociaux 41 (1994), S. 165-177 
    ISSN: 1420-9098
    Keywords: environmental variability ; learning ; memory ; seed-harvester ants ; Sonoran Desert
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Foragers of the antsMessor pergandei andPogonomyrmex rugosus experience differing levels of variability in the distribution of seeds they harvest due to species-specific differences in foraging behavior.Messor pergandei foragers experience more variable seed distributions and densities, learn to recognize a novel seed faster but forget this information faster thanP. rugosus, which experiences more constant seed distributions even in the same habitat. Rate of learning to recognize a novel seed species was negatively associated with measures of seed species diversity for both ants.Messor pergandei foragers respond to variation in seed density by varying number of seeds handled per seed harvested, whileP. rugosus foragers do not. Memory of a novel seed exceeds forager longevity, due perhaps to use of seed caches as a type of information center.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume De nouvelles colonies du termites champignonisteMicrotermes sp. cf.usambaricus (Macrotermitinæ) ont été élevées avec succès en laboratoire jusqu'au stade de l'établissement d'une meule à champignons viable. La première meule est «ensemencée» avec leTermitomyces par la femelle reproductrice, qui a ingéré des spores asexuées (conidies) de la meule avant de quitter le nid parental. Ces conidies survivent dans le tube digestif jusqu'au moment où la première meule à champignons est construite, 10–11 semaines après la fondation de la colonie. La meule est entièrement faite de matières fécales et les observations préliminaires semblent indiquer que 5 semaines de digestion par le champignon sont nécessaires avant que la meule soit consommée par lesMicrotermes ouvriers. Chez les Macrotermitinæ, l'aptitude des colonies nouvellement fondées à produire une meule à champignons viable n'a été mise en évidence que chez le genreMicrotermes et chez une seule espèce du genreMacrotermes. Dans les deux cas, les reproducteurs transportent les spores du champignon dans leur tube digestif. Cette adaptation très évoluée à la symbiose fongique a de toute évidence joué un rôle important dans la large répartition et l'abondance du genreMicrotermes.
    Notes: Summary Incipient colonies of the fungus-growing termiteMicrotermes sp. nr.usambaricus (Macrotermitinæ) have been successfully cultured in the laboratory up to the stage where a viable fungus comb was established. The primordial fungus comb is inoculated with fungusTermitomyces by the female reproductive which ingests asexual spores (conidia) from the comb before leaving the parental nest. These conidia survive in the digestive tube until, 10–11 weeks after colony foundation, the first new fungus comb is built. The comb is built entirely of fæcal material and appears from these preliminary observations to require 5 weeks digestive action by the fungus before it is re-consumed by theMicrotermes workers. Within the Macrotermitinæ the ability of incipient colonies to produce a viable fungus comb has been demonstrated only in the genusMicrotermes and a single species of the genusMacrotermes. In both cases the reproductives transport the fungal spores in their digestive tube. This highly evolved adaptation to the fungal symbiosis has clearly played an important part in establishing the wide distribution and abundance of the genusMicrotermes.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The myrmicine ant Decamorium uelense is a predator of small termites which feed inside their food sources of roots and plant debris. The ant uses a specialized recruitment regime to secure its prey. A scout ant searches for foraging termites and returns to the nest where it recruits a column of 10–30 ants which attack and immobilize the termites. A mass recruitment phase is then instigated, with larger numbers of ants retrieving the prey. The major prey item is Microtermes (consumed at an annual rate of 632 termites m-2), with other small termites accounting for 0.5% of the total predation. The annual predation of Microtermes in primary savanna woodland by D. uelense removes 74% of the standing population.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary At Mokwa, in the Nigerian southern Guinea Savanna, Macrotermitinae are the only recorded prey of the obligate termite predator, Megaponera foetens. The main prey species is Macrotermes bellicosus (141 termites m-2 a-1) followed by Odontotermes spp. (42 termites m-2 a-1). Predation on other species, Ancistrotermes cavithorax, Macrotermes subhyalinus and Microtermes spp., amounts to only 10 termites m-2 a-1. Macrotermes bellicosus is not the most abundant termite in the primary savanna. It is concluded that factors including termite abundance, termite foraging regimes and seasonality, termite biomass and the reactions of the ants to the termites and their products are involved in successful predation of termites by Megaponera.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 79 (1972), S. 85-96 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sectioning of the afferent nerves (NCCl and NCCll) to the locust corpus cardiacum prevents thein vivo release of adipokinetic hormone from the glandular lobes. This failure to release the hormone during flight and the consequent lack of lipid mobilisation brings about an impairment of flight performance which can be corrected by injections of corpus cardiacum extracts. Sectioning of the NCCl and NCCll reduces markedly the activity of the corpora allata. However, the poor flight performance of allatectomised locusts is not related to an inability to mobilise lipid since injections of corpus cardiacum extract which will mobilise fat body lipid in these locusts have no effect on flight performance. The results of individual sectioning of the NCCl and NCCll suggest that a double innervation of the glandular lobes functionsin vivo to control adipokinetic hormone release but that the NCCl alone may control the release of the diuretic hormone.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 85 (1973), S. 213-220 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The amounts of adipokinetic and diuretic hormone in the separate storage and glandular lobes of the locust corpora cardiaca during the imaginal moult and up to the onset of sexual maturation have been measured. The levels of the hormones are high prior to the imaginal moult, fall at emergence and increase during the somatic growth period. The effects of surgical interference with the neuroendocrine system upon the hormonal content of the corpora cardiaca have been investigated. Cautery of the brain neurosecretory cells or allatectomy in mature locusts has no effect on the content of adipokinetic hormone. Diuretic hormone is absent from the storage lobes of locusts deprived of their cerebral neurosecretory cells but normal levels are present in the corpora cardiaca of allatectomised animals. Severance of the nervus corporis cardiacum I and II reduces the level of diuretic hormone in the storage lobes of the corpora cardiaca but is without effect on the levels of adipokinetic hormone in the glandular lobes.
    Type of Medium: Electronic Resource
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  • 10
    Publication Date: 2013-10-23
    Description: Environmental sensor networks are developing rapidly to assess changes in ecosystems and their services. Some ecosystem changes involve thresholds, and theory suggests that statistical indicators of changing resilience can be detected near thresholds. We examined the capacity of environmental sensors to assess resilience during an experimentally induced transition in a...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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