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1.
Lukas Schärer Dagmar Knoflach Dita B. Vizoso Gunde Rieger Ursula Peintner 《Marine Biology》2007,152(5):1095-1104
The Labyrinthulomycota are a relatively poorly studied group of heterotrophic unicellular eukaryotes. They comprise three
lineages, labyrinthulids, thraustochytrids, and aplanochytrids, which are all primarily marine organisms and considered to
be important components of marine microbial communities. Recently a number of Labyrinthulomycota have been implicated as parasites
of marine (but also terrestrial) plants and marine molluscs. Here we describe a new species of thraustochytrid, Thraustochytrium caudivorum sp. nov. that we have isolated from laboratory cultures of Macrostomum lignano (Rhabditophora, Macrostomorpha), a marine free-living flatworm. In these worms T. caudivorum can cause lesions, which start at the tip of the tail plate and which can lead to the dissolution of the posterior part of
the animal. Although the worms can frequently cure these lesions and regenerate the lost parts, the lesions can also result
in the complete dissolution of the animal. We describe this thraustochytrid based on pure agar cultures and infestations in
the worm cultures. Moreover, we describe its pathological effects on the worms and its morphology using both light and electron
microscopy. In addition, we report a phylogenetic analysis using a partial 18S rDNA sequence that allows us to place this
new species within the thraustochytrids. Finally, we outline a protocol that allows to permanently remove the parasites from
infested worm cultures. We conclude that thraustochytrids represent a novel group of parasites of free-living flatworms.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
Fine-scale movement patterns in penaeid prawns are rarely observed in situ, but are essential in understanding habitat use,
foraging, and anti-predator behaviour. Acoustic telemetry was applied to examine the activity, space utilization, and habitat
use of the eastern king prawn Penaeus (Melicertus) plebejus, at small temporal and spatial scales. Tracking of sub-adult P. plebejus (n = 9) in Wallagoot Lake (36.789°S, 149.959°E; 23 April–12 May 2009) and calculation of a minimum activity index (MAI) revealed high variation in activity rates across diel periods and in different habitats. Elevated activity rates and movement
indicated foraging in unvegetated habitats during the night. Areas within the 95 and 50% space utilization contours averaged
2,654.1 ± 502.0 and 379.9 ± 103.9 m2, respectively, and there was a significant negative relationship between these areas and prawn activity rates in unvegetated
habitats. This study provides the first estimates of prawn activity rates and space utilization in the field. Application
of acoustic telemetry can increase knowledge of prawn movements and their interactions with other marine species in different
habitats. 相似文献
3.
The experiments were undertaken to measure, for the first time, cardiac output in yellowtail (Seriola quinqueradiata) during exposure to a harmful red tide flagellate (Chattonella marina). The responses were compared with those during exposure to environmental hypoxia to evaluate the significance of the drop of arterial oxygen partial pressure (PaO2) in the fish-kill mechanisms by C. marina. PaO2 immediately decreased, whereas heart rate (HR) was maintained until shortly before death during exposure to C. marina. Suffocation developing during the exposure resulted from a decrease in blood oxygen content, but not from lowered blood flow to the tissue. Although exposure to both C. marina and hypoxia immediately decreased PaO2, arterial oxygen content (CaO2) and pH (pHa) were significantly lower, whereas HR and cardiac output (&Qdot;) remained significantly higher, for the C. marina-exposed fish than for hypoxia-exposed fish. Although the drop in PaO2 appears to play a pivotal role in the mechanisms of fish death by C. marina, other physiological response(s) should also be considered. 相似文献
4.
Telomere length has been purported as a biomarker for age and could offer a non-lethal method for determining the age of wild-caught
individuals. Molluscs, including oysters and abalone, are the basis of important fisheries globally and have been problematic
to accurately age. To determine whether telomere length could provide an alternative means of ageing molluscs, we evaluated
the relationship between telomere length and age using the commercially important Sydney rock oyster (Saccostrea glomerata). Telomere lengths were estimated from tissues of known age individuals from different age classes, locations and at different
sampling times. Telomere length tended to decrease with age only in young oysters less than 18 months old, but no decrease
was observed in older oysters aged 2–4 years. Regional and temporal differences in telomere attrition rates were also observed.
The relationship between telomere length and age was weak, however, with individuals of identical age varying significantly
in their telomere length making it an imprecise age biomarker in oysters. 相似文献
5.
Antarctic limpets, Nacella concinna, from the Admiralty Bay (King George Island, South Shetlands) for at least part of the year (austral winter) co-exist with
predatory sea stars Lysasterias sp. Our laboratory and field experiments established that the presence of Lysasterias sp. or its odour had considerable influence upon their behaviour. Limpets’ responses, consisting of shell mushrooming, shell
rotation and flight, were distinctly different from their reaction to other stimuli, such as food and conspecific odours,
or mechanical stimulation. Moreover, a significant impact of sea star presence on limpets’ activity was observed, with limpets
fleeing to a distance of 60 cm from the predator. Such reactions allow limpets to lower the incidence of sea star predation,
but at the cost of presumptive disrupting of foraging and an additional energy expended for locomotion. A visible difference
was noted between two limpet populations, with the rockpool limpets responding only after physical contact with being touched
by a sea star, and the subtidal ones responding at a distance of up to 20 cm. 相似文献
6.
Halictine bees exhibit a wide range of social behaviour that varies both inter- and intraspecifically. Although previous studies
suggested that the intraspecific variation might be attributed to temperature differences, there was no direct evidence to
detect the relationships between temperature and socialities. Lasioglossum (Evylaeus) baleicum exhibited solitary behaviour in a cooler locality (Kawakita) because of the shorter breeding season; in a warmer locality
(Nishioka Park), however, this bee species exhibited eusociality at sunny site and solitary behaviour at shady site, whereas
a molecular phylogeny confirms that all of these colonies are evidently conspecific. Therefore, we examined the effect of
degree-day accumulation on the sympatric social variation of L. baleicum by rearing the bees to calculate the threshold temperature. Whereas they showed high mortality, the threshold temperature
was estimated to be 10.33°C and the expected degree-day accumulation was 340 degree days. When we use this value of a degree-day
accumulation to estimate the expected eclosion date, the estimated dates were always consistent with observed eclosion dates.
In any sites where the bees were solitary, the degree-day accumulation was not enough for the second eclosion by the end of
the bee-active season. In Nishioka Park, sex ratio of the first brood was female biased, and daughters were smaller than mothers;
in Kawakita, however, there was no sex bias, and daughters were as large as their mothers indicating that the foundresses
seem to produce gyne-sized females in Kawakita but worker-sized females in Nishioka though these females do not become workers
at shady site. 相似文献
7.
Corals harbouring genetically mixed communities of endosymbiotic algae (Symbiodinium) often show distribution patterns in accordance with differences in light climate across an individual colony. However, the
physiology of these genetically characterised communities is not well understood. Single stranded conformation polymorphism
(SSCP) and real time quantitative polymerase chain reaction (qPCR) analyses were used to examine the genetic diversity of
the Symbiodinium community in hospite across an individual colony of Acropora valida at the spatial scale of single polyps. The physiological characteristics of the polyps were examined prior to sampling with
a combined O2 microelectrode with a fibre-optic microprobe (combined sensor diameter 50–100 μm) enabling simultaneous measurements of O2 concentration, gross photosynthesis rate and photosystem II (PSII) quantum yield at the coral surface as a function of increasing
irradiances. Both sun- and shade-adapted polyps were found to harbour either Symbiodinium clade C types alone or clades A and C simultaneously. Polyps were grouped in two categories according to (1) their orientation
towardps light, or (2) their symbiont community composition. Physiological differences were not detected between sun- and
shade-adapted polyps, but O2 concentration at 1,100 μmol photons m−2 s−1 was higher in polyps that harboured both clades A and C symbionts than in polyps that harboured clade C only. These results
suggest that the acclimatisation of zooxanthellae of individual polyps of an A. valida colony to ambient light levels may not be the only determinant of the photosynthetic capacity of zooxanthellae. Here, we
found that photosynthetic capacity is also likely to have a strong genetic basis and differs between genetically distinct
Symbiodinium types. 相似文献
8.
Embryos of the large infaunal clam Laternula elliptica and the scallop Adamussium colbecki, from Antarctica, were cultured over an 18-month period. Their development rates were extremely slow, taking 240 and 177 h,
respectively, to reach the trochophore stage. This is ×4 to ×18 slower than related clams and scallops from temperate latitudes.
The relationship between temperature and development rate for bivalve molluscs shows the expected slowing with reduced temperature
(Q
10 in the range 2–4) for temperate and tropical species. However, the slowing at polar latitudes is much stronger than at warmer
waters, and all of the limited data for Antarctic species are well above the Arrhenius plot for the overall bivalve data,
and the Q
10 value for Antarctic to cool temperate species is 11.8, well outside the expected range for biological systems. Either the
relationships describing the effects of temperature on the kinetics of biological systems do not apply to Antarctic bivalve
molluscs, or some other factor that cannot be compensated for becomes important at low temperature. In the laboratory, L. elliptica embryos stayed viable in very sticky egg capsules for up to 18 months without hatching. However, even the disturbance of
removing eggs using a pipette ruptured some egg capsules allowing embryo release. Gametogenesis in Antarctic marine invertebrates
is almost universally slowed compared to temperate species, with nearly all cases documented requiring more than 1 year to
complete oogenesis. The only exception so far appears to be A. colbecki, which has a 1-year gametogenic cycle. The data here indicate that it has been unable to adapt embryonic development in a
similar way, and we are not aware of any exceptions to the markedly slowed development at low temperature rule. 相似文献
9.
Echinoderms are major predators of anemones in temperate ecosystems. The fate of two algae, zooxanthellae and zoochlorellae, after their host anemone (Anthopleura elegantissima Brandt) was consumed by the leather star Dermasterias imbricata Grube was determined in experiments conducted in July and August 2004. Productivity, photosynthetic pigments, and mitotic index (percent of cells dividing) were used as indicators of algal health; algae released after leather stars consumed their host were compared with algae freshly isolated from anemones. Two types of waste products contained algae: pellets resulting from extraoral digestion, and feces. Zooxanthellae and zoochlorellae isolated from these waste products were photosynthetic, although to different extents. For algae from feces and pellets, light-saturated photosynthetic rates (P
max) were 85 and 13%, respectively, of P
max of freshly isolated zooxanthellae; and were 20 and 46%, respectively, for zoochlorellae. The photosynthetic pigments and mitotic index (percent of dividing cells) were not altered by the feeding activities of the leather star. These results show that algae released by seastar predation on their hosts remain viable, and are hence available for establishing symbioses in A. elegantissima and other potential hosts. 相似文献
10.
D. Hedgecock S. Launey A. I. Pudovkin Y. Naciri S. Lapègue F. Bonhomme 《Marine Biology》2007,150(6):1173-1182
The great fecundity and very high larval mortality of most marine invertebrates and fish make possible substantial variance
in the number of offspring contributed by adults to subsequent generations. The reproductive success of such organisms may
thus resemble a sweepstakes lottery, in which a minority of progenitors succeeds in replacing an entire population, while
the majority fails to procreate. One specific prediction of this hypothesis, that genetic diversity of newly settled cohorts
should be less than that of the adult population, is tested in the present study. Microsatellite DNA markers were examined
in naturally spawned juvenile European flat oysters Ostrea edulis (L.), collected over a 12-day period in 1993 from the western Mediterranean Sea, near Sète, France (43°32′N, 3°56′E) and
grown out for a period of up to 10 months. Variation in these juveniles was compared to that in a pooled sample of adults
collected in 1994 from two locations (Thau Lagoon and Port St. Louis) that had statistically homogeneous allelic frequencies.
Though nearly twice as large as the pooled adult sample, the juvenile sample had only 60% of the adult allelic diversity.
Analyses of linkage disequilibrium and kinship, as well as estimation of the effective number of parents, suggested that 10–20
adults produced this juvenile cohort. This observation supports the hypothesis of sweepstakes reproductive success and suggests
that partial inbreeding may occur even in species with large populations and dispersing planktonic larvae.
Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at . 相似文献
11.
Mirna H. R. Seleghim Simone P. de Lira Patrícia T. Campana Roberto G. S. Berlinck Marcio R. Custódio 《Marine Biology》2007,150(5):967-975
Ascidians are a notable source of nitrogen-bearing secondary metabolites with a wide range of biological activities. Although
many biologically active compounds have been isolated from ascidians, it is often unclear whether the animal or associated
microbial symbionts such as bacteria or fungi are the true biosynthetic source of the metabolites. We have addressed the question
of the biosynthetic source of the alkaloids granulatimide and isogranulatimides by localizing these compounds within the ascidian.
In this work, we demonstrate that granulatimide is stored in Didemnum
granulatum tunic bladder cells. Analysis by confocal fluorescence microscopy at the granulatimide emission range indicated the presence
of fluorescent cells as highly vacuolated cells found dispersed in the ascidian tunic. Since this is the most exposed ascidian
tissue, it is possible that these alkaloids may have a protective role, either as sunscreens and/or as feeding deterrents. 相似文献
12.
Bacterial isolates from multi-species biofilms were identified by 16S rDNA gene sequences and investigated for their inductive
effects as monospecific biofilms on larval metamorphosis of Mytilus galloprovincialis. Alteromonas sp. 1 biofilm was found to have inductive activity, which increased with increasing cell density. The cue(s) of Alteromonas sp. 1 biofilm responsible for inducing larval metamorphosis was further investigated. Treatment of the biofilm with formalin,
ethanol, heat or ultraviolet irradiation resulted in a significant reduction in the inductive activity of Alteromonas sp. 1, and the crude extract of surface-bound products of the biofilm showed no activity. These results indicated that if
the cue was a surface-bound chemical cue, it was unstable, or susceptible to the treatments or the extraction process. On
the other hand, the inductive activity of treated biofilms had a linear regression to the cell survival of bacteria, indicating
a metabolically active biofilm was a requirement for larval metamorphosis. Conditioned water of the biofilm did not induce
larvae to metamorphose. However, larval crawling behavior in the conditioned water was the same as that in the biofilm prior
to larval metamorphosis, and significantly different to larval behavior in seawater. This indicated that a potential or partial
waterborne cue existed, but remained inactive when alone. A synergistic effect of the conditioned water with formalin-fixed
Alteromonas sp. 1 biofilm resulted in a significant increase in larval metamorphosis. Heat treatment and fractionation of the conditioned
water demonstrated that the waterborne cue was heat-stable and <3,000 Da in molecular weight. Platinum-coating, Lentil Lectin
and Wheat Germ Agglutinin treatments of the formalin-fixed biofilm significantly reduced its synergistic effect with the conditioned
water, suggesting that a surface-bound cue was present on the biofilm and that the cue might be associated with the bacterial
exopolysaccharide or glycoprotein. Evidence presented here suggests that two chemical cues derived from bacteria act synergistically
on larval metamorphosis of Mytilus galloprovincialis. 相似文献
13.
Short-term (3 h) changes in concentration of chlorophylls and their derivatives in stage V Pseudodiaptomus euryhalinus and their fecal material were followed by HPLC during a 24 h experiment. Copepodites were fed with the prasinophyte Tetraselmis suecica. Intact chlorophyll a and b were found in animals and fecal material and had similar dynamics of accumulation over time. The extent of transformation of chlorophyll a and b to colorless compounds was different with chlorophyll a being more extensively degraded. Additionally, several chlorophyll derivatives (pheophytin and pyropheophytin-like pigments) were found. Pyropheophytin a was the most abundant followed by pheophytin b, pheophytin a, and pheophorbide a. Relative amounts of pheopigments were different in copepodites and fecal material, and pheophytin a, pheophorbide a, and pheophytin b concentrations were low and variable. The amount of ingested chlorophyll recovered as chlorophyll a and its derivatives in fecal and copepodite pools was generally low (<5%), with one exception occurring after 9 h, when it accounted for >70%. These data suggest individual pheopigments are produced at different rates and that chemical or enzymatic mechanisms in the gut of copepodites act on the two chlorophylls in different ways. 相似文献
14.
Susanna Andersson 《Chemoecology》2003,13(1):1-11
Summary. For butterflies to be efficient foragers, they need to
be able to recognize rewarding flowers. Flower signals such as colours
and scents assist this recognition process. For plant species to attract
and keep butterflies as pollinators, species-specific floral signals are
crucial. The aim of this study is to investigate foraging responses to
floral scents in three temperate butterfly species, Inachis io L.
(Nymphalidae), Aglais urticae L. (Nymphalidae), and
Gonepteryx rhamni L. (Pieridae), in behavioural choice
bioassays. The butterflies were allowed to choose bet-ween flower models
varying in scent and colour (mauve or green). Flowers or vegetative
parts from the plants Centaurea scabiosa L. (Asteraceae),
Cirsium arvense (L.) (Asteraceae), Knautia arvensis (L.)
(Dipsacaceae), Buddleja davidii Franchet (Loganicaeae), Origanum vulgareL. (Lamiaceae), Achillea millefolium L. (Asteraceae), and
Philadelphus coronarius L. (Hydrangiaceae) were used as scent
sources. All visits to the models — those that included probing and
those that did not — were counted, as was the duration of these
behaviours. Both flower-naive and flower-experienced (conditioned to
sugar-water rewards, the colour mauve, and specific floral scents)
butterflies were tested for their preference for floral versus
vegetative scents, and to floral scent versus colour. The butterflies
were also tested for their ability to switch floral scent preferences in
response to rewards. Flower-naive butterflies demonstrated a preference
for the floral scent of the butterfly-favourable plants C.
arvense and K. arvensis over the floral scent of the non-favourable
plants Achillea millefolium (Asteraceae), and Philadelphus
coronarius cv. (Hydrangiaceae). Most of the butterflies that were
conditioned to floral scents of either C. arvense, K. arvensis,
or B. davidii readily switched theirfloral scent preferences to
the one most recently associated with reward, thus demonstrating that
floral scent constancy is a result from learning. These findings suggest
that these butterflies use floral scent as an important cue signal to
initially identify and subsequently recognize and distinguish among
rewarding plants.
Received 2 September 2001; accepted 9 September 2002. 相似文献
15.
Summary. Sequestration of plant toxins in herbivores is often
correlated with aposematic coloration and gregarious behaviour. Larvae
of Pieris brassicae show these conspicuous morphological and behavioural
characteristics and were thus suggested to sequester glucosinolates that
are characteristic secondary metabolites of their host plants. P. rapaeare camouflaged and solitary, and are thus not expected to sequester. To
test this hypothesis and to check the repeatabi-lity of a study that did
report the presence of the glucosinolate sinigrin in P. brassicae,
larvae were reared on three species of Brassicaceae (Sinapis alba,
Brassica nigra and Barbarea stricta), and different leaf and insect
samples were taken for glucosinolate analysis. The major host plant
glucosinolates could only be found in traces or not at all in larval
haemolymph, bled or starved larvae, faeces or pupae of both species or
P. brassicae regurgitant. Haemolymph of both Pieris spp. was not
rejected by the ant Myrmica rubra in dual-choice assays; the regurgitant
of P. brassicae was rejected. This suggests the presence of compounds
other than glucosinolates that might be sequestered in or produced by P.
brassicae only. In faeces of both Pieris spp. a compound which yielded
4-hydroxybenzylcyanide (HBC) upon incubation with sulfatase was detected
in high concentrations when larvae had been reared on S. alba. This
compound may be derived from hydrolysis of sinalbin, the main
glucosinolate of that plant. The unidentified HBC progenitor was
apparently not sequestered in the two Pieris spp., and was not detected
in faeces of larvae reared on B. nigra or B. stricta.
Received 18 July 2002; accepted 11 September 2002. 相似文献
16.
Eun Jung Choy Qtae Jo Hyo-Bang Moon Chang-Keun Kang Ju-Chan Kang 《Marine Biology》2007,151(1):157-165
The time-course of uptake and elimination of benzo(a)pyrene (BaP) for the Pacific oyster, Crassostrea gigas and reproduction damage and reproductive outputs were studied. Sexually immature C. gigas broodstock were fed for 28 days with live algae grown in four BaP solutions of 0, 50, 500, and 5,000 μg L−1 (hereafter, control, 50, 500, and 5,000 oysters) and were subsequently conditioned to maturation by a feeding with BaP-free
live algae under temperature manipulation for another 28 days. The 5,000 μg L−1 oysters gained a steady state concentration, around 30,000 ng g−1 d.w. for digestive gland, a week earlier compared to the 500 μg L−1 oysters. The earlier gain or longer persistence of the steady state concentration influenced elimination of BaP, with an
eliminating trend for 500 μg L−1 oysters, while no elimination for 5,000 μg L−1 oysters. The maternal persistence of the steady state concentration resulted in significant damages in the reproductive success
and their reproductive outputs in terms of the hatching rate and larval growth, survival, and settlement. The 50 μg L−1 oysters remained far below the steady state concentration, and showed a manifest eliminating behavior during the subsequent
BaP-free 28 day maturation period. The reproductive success and initial larval events of 50 μg L−1 oysters were comparable to those of control. However, the damage potential of the 50 μg L−1 oysters might be more significant if their maternal exposure continued beyond 28 days, since the accumulation profile at this
dose was linear. 相似文献
17.
Susanna Andersson 《Chemoecology》2003,13(1):13-20
Summary. To better understand the biological role of floral scents for
butterflies, electrophysiological responses to floral scents were
investigated using combined gas chromatography and electroantennographic
detection (GC-EAD). The antennal responses of three butterfly species,
Aglais urticae L. (Nymphalidae), Inachis io L. (Nymphalidae), and
Gonepteryx rhamni L. (Pieridae) to floral scent compounds from both
natural and synthetic mixtures were examined. Floral scents were
collected from the butterfly nectar plants Cirsium arvense (L.)
(Asteraceae), and Buddleja davidii Franchet cv. (Loganicaeae) with
dynamic head-space methods on Tenax-GR and eluted with pentane. These
eluates, composed of natural floral scent blends, represent an array of
compounds in their natural state. In the GC-EAD analyses eleven
compounds were identified from C. arvense with the benzenoid compound
phenylacetaldehyde in highest abundance. Seventeen compounds were
identified from B. davidii with the irregular terpene oxoisophorone in
highest abundance. Thirty-nine synthetic floral scent compounds were
mixed in pentane, in equal amounts; about 35 ng were allowed to reach
the antennae. The butterflies showed antennal responses to most of the
floral scent compounds from both natural and synthetic blends except to
the highly volatile monoterpene alkenes. Certain benzenoid compounds
such as phenylacetaldehyde, monoterpenes such as linalool, and irregular
terpenes such as oxoisophorone, were emitted in relatively large amounts
from C. arvense and B. davidii, and elicited the strongest antennal
responses. These compounds also elicited strong antennal responses when
present in the synthetic scent blends. Thus, the butterflies seem to
have many and /or sensitive antennal receptors for these compounds,
which points to their biological importance. Moreover, these compounds
are exclusively of floral scent origin. For B. davidii, which depends
highly on butterflies for pollination, the exclusive floral scent
compounds emitted in high abundance could be the result of an adaptive
pressure to attract butterflies.
Received 2 Septemter 2001; accepted 9 September 2002. 相似文献
18.
Michael G. Frick Kerry Kopitsky Alan B. Bolten Karen A. Bjorndal Helen R. Martins 《Marine Biology》2011,158(8):1699-1708
Grapsoid crabs of the genera Planes and Plagusia are commonly referred to as “rafting crabs” due to their propensity to live on flotsam and pelagic marine animals. Planes minutus and Planes major (=Planes cyaneus) are epibionts of sea turtles. Occurrences of grapsoid crabs in the genera Planes and Plagusia were evaluated on a total of 27 olive ridley sea turtles, Lepidochelys olivacea, from the eastern tropic Pacific (1998–2001) and the Hawaiian Islands (2002) captured in July–December each year. This is
the first report of Planes marinus and Plagusia
squamosa on sea turtles, and of P. major, P. marinus, and P. squamosa in sympatry on a confined substrate. Stomach content analyses showed P. major and P. marinus consumed a variety of neuston and marine vegetation, with the former consuming considerably more animal material. Epibiotic
P. squamosa consumed mostly plant material. The three Planes species had distinctive differences in gastric mill tooth morphology. The versatile mouthparts of P. marinus are described and resemble those of their congeners. Most female P. major and P. marinus collected were ovigerous and present in all survey months. 相似文献
19.
Johannes Stökl Robert Twele Dirk H. Erdmann Wittko Francke Manfred Ayasse 《Chemoecology》2007,17(4):231-233
Summary.
Ophrys flowers mimic the female produced sex pheromone of their pollinator species to attract males for pollination. The males try
to copulate with the putative female and thereby pollinate the flower. Using electrophysiological and chemical analyses, floral
volatiles released by O. iricolor as well as the female sex pheromone of its pollinator species, Andrena morio are investigated. Overall, 38 peaks comprising 41 chemical compounds, were found to release reactions in the antennae of
male A. morio bees. Analyses using coupled gas chromatography-mass spectrometry revealed the presence of alkanes and alkenes with 20 to
29 carbon atoms, aldehydes (C9 to C24) and two esters. Almost all of those compounds were found in similar proportions in
both, the floral extracts of O. iricolor and cuticle surface extracts of A. morio females. The pattern of biologically active volatiles described here is very similar to that used by other Ophrys species pollinated by Andrena males. 相似文献
20.
The reconstruction of past climates is a major challenge. One approach is the use of paleoceanography, which looks for clues
to the past activity of deep-sea currents by associating them with the melting of the poles. In different sampling zones,
fossil biomarkers are used to reconstruct the oxygenation levels of the sea bottom. Among the ostracods (crustaceans), the
family Cytherellidae is considered to be resistant to significant decreases in oxygen and their fossil valves are used as
biomarkers for oxygenation levels in the past. We studied the basic principles behind Cytherella cf. abyssorum’s ability to adapt to variations in water oxygenation levels in an attempt to determine what could differentiate it from
other ostracods. Cytherella cf. abyssorum Sars 1866 has an activity level and ventilatory frequency only half that of ostracods studied previously. When subjected
to a decrease in oxygenation, it demonstrates the beginnings of ventilatory adaptation which is unknown in the other studied
ostracods. Some morpho-functional aspects are also remarkable, such as the presence of thick valves, which can close hermetically
by means of powerful adductor muscles. Compared with already studied ostracods, Cytherella cf. abyssorum has, therefore, characteristics which suggest an ability to present increased resistance in hypoxia. We discuss these results
in the paleoceanographical context by describing a scenario suggesting why an increased proportion of the ostracod population
could indicate the existence of ocean bottoms with low oxygenation. 相似文献