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1.
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
2.
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
3.
Jacques M. Pasteels Claudine Theuring Donald M. Windsor Thomas Hartmann 《Chemoecology》2003,13(1):55-62
Summary. Sequestration and processing of pyrrolizidine alkaloids
(PAs) by leaf beetles of the genus Platyphora were investigated. Tracer
experiments with labeled alkaloids were performed with P. eucosma
feeding on Koanophyllon panamense (Asteraceae, tribe Eupatorieae). P.
eucosma catalyzes the same reactions previously demonstrated for P.
boucardi specialized to Prestonia portobellensis (Apocynaceae): (i)
epimerization of rinderine to intermedine; (ii) esterification of
retronecine yielding insect-specific PAs; (iii) efficient transport of
the PAs as free bases into the defensive secretions. P. bella feeding on
Tournefortia cuspidata (Boraginaceae) shows the same sequestration
behavior and ability to synthesize the specific retronecine esters. P.
ligata, a species phylogenetically closely related to the PA adapted
species and clustering in the same clade, but feeding on a host plant
devoid of PAs, feeds easily on PA treated host-plant leaves, but does
not sequester or metabolize PAs. P. kollari a species clustering outside
the PA clade refused to feed on its food-plant leaves painted with PAs.
The results are discussed in relation to host-plant selection of the PA
adapted species and the role of PAs in chemical defense.
Received 20 September 2002; accepted 18 November 2002. 相似文献
4.
Summary. The ontogeny of pyrrolizidine alkaloid (PA) synthesis
and constraints on defence level during the seedling stage were examined
in the annual Senecio vulgaris and the monocarpic perennial
Senecio jacobaea. In both species, PAs were actively
synthesized from the onset of seedling growth so that juvenile stages
did not go through an undefended stage. Roots are known to be the
exclusive sites where PAs are produced. Root biomass was the single most
important biomass parameter explaining variation in total PAs per
seedling. All correlation coefficients between—relative growth
rate and PA concentration were negative, but none was significant.
However, a significant negative—correlation was found between
shoot to root ratio and PA concentration in S. jacobaeaseedlings, suggesting a dilution effect of the PAs. Earlier studies have
shown that the shoot to root ratio is positively correlated with
relative growth—rate of established S. jacobaea plants.
It is therefore suggested that young S. jacobaea plants
with a high shoot to root ratio and hence a high growth capacity
necessarily have lower PA defence levels than plants with a low
shoot to root ratio.
Received 10 July 2002; accepted 16 November 2002. 相似文献
5.
Summary. We tested the hypothesis that aggregation behaviour of the
firebrat, Thermobia domestica (Packard) (Thysanura: Lepismatidae), an
inhabitant of enclosed microhabitats, is mediated, at least in part, by
a pheromone. Individual insects were released into the central chamber
of a 3-chambered olfactometer and test stimuli were placed in lateral
chambers. Paper discs previously exposed for 3 days to 10 female, male,
or juvenile T. domestica were all preferred by female, male, or juvenile
T. domestica over unexposed paper discs, indicating the presence of an
aggregation/arrestment pheromone. In additional experiments, frass and
scales from female T. domestica, tested singly and in combination,
proved not to be the source of the pheromone. Physical contact was
required for pheromone recognition, indicating that the pheromone
arrests rather than attracts conspecifics. Arrestment by the
long-tailed silverfish, Ctenolepisma longicaudata Escherich
(Thysanura: Lepismatidae), but not by the common silverfish, Lepisma
saccharina L. (Thysanura: Lepismatidae), to T. domestica exposed
paper discs suggests closer phylogenetic relatedness between C.
longicaudata and T. domestica, than between C.
longicaudata and L. saccharina. Whether C.
longicaudata or L. saccharina produce an aggregation
signal, and whether T. domestica respond to this signal is unknown.
Received 10 June 2002; accepted 30 September 2002. 相似文献
6.
Summary. Sensitivities to methyl eugenol of three sibling species in the Bactrocera dorsalis complex were compared. The degree of species sensitivity to methyl eugenol, i.e. B. dorsalis > B. papayae > B. carambolae (in decreasing order), was concomitant with the species age-related response to methyl eugenol as previously reported. The
ability to consume methyl eugenol by the three sibling species showed similar trend - the average ME consumption per male
was 0.70 ml for B. dorsalis, 0.58 ml B. papayae and 0.18 μl B. carambolae. Results obtained were discussed in relation to area-wide control of fruit fly.
Received 21 April 2002; accepted 9 July 2002 相似文献
7.
Letizia Mattiacci Sara Rudelli Bettina Ambühl Rocca Sem Genini Silvia Dorn 《Chemoecology》2001,11(4):167-173
Summary. Plant responses to herbivory might directly affect the herbivore (“direct” defences) or might benefit the plant by promoting
the effectiveness of natural antagonists of the herbivores (“indirect” defences). Brussels sprouts attacked by Pieris brassicae larvae release volatiles that attract a natural antagonist of the herbivores, the parasitoid Cotesia glomerata, to the damaged plant. In a previous study, we observed that feeding by caterpillars on the lower leaves of the plant triggers
the systemic release of volatiles detectable by the parasitoids from upper leaves of the same plant.?The role of these systemically
induced volatiles as indirect defence and the dynamics of their emission were investigated in wind-tunnel dual choice tests
with C. glomerata. The systemically induced emission of volatiles varied depending on leaf age and on plant age. Systemic induction affected
parasitoid effectiveness, as induced plants could be more easily located by parasitoids than non-induced ones.?The role of
the systemic induction as a direct defence was investigated through behavioural and feeding tests with P. brassicae. In dual choice assays, 1st instar larvae preferred to feed and fed more on systemically induced than on non-induced leaves.
In single choice assays, the leaf area consumed by caterpillars was larger on systemically induced leaves than on non-induced
control leaves. However, caterpillars fed on systemically induced leaves attained the same weight as those feeding on non-induced
controls. In addition, P. brassicae pupae whose larvae were fed on systemically induced leaves had longer developmental times than those of larvae fed on non-induced
leaves. Adult oviposition behavior was not influenced by systemic induction.?We conclude that systemically induced responses
in cabbage might reduce P. brassicae fitness both directly, by affecting their development and feeding behavior and indirectly by making caterpillars and pupae
more vulnerable to attack by carnivores. The occurrence of a possible relationship between direct and indirect defence is
discussed.
Received 24 January 2001; accepted 3 May 2001. 相似文献
8.
Phylogenetic analyses have demonstrated that nonfeeding larvae have evolved from feeding larvae many times among marine invertebrates.
In light of this observation, it is surprising that an intermediate strategy, a larva that can feed but is provisioned with
enough energy to metamorphose without acquiring exogenous food (i.e., facultative planktotrophy), is rare. A hypothesis for
the lack of facultative planktotrophic species among marine invertebrates is that the transition from feeding to nonfeeding
is rapid due to this intermediate stage being evolutionarily unstable. Evidence that would support this hypothesis is if species
with facultative planktotrophy have reduced food assimilation when compared with obligate planktotrophs. We studied a species
with facultative planktotrophic larvae, Clypeaster rosaceus, that is very near the boundary between facultative and obligatory planktotrophy, to answer two questions: (1) does feeding
during the larval stage result in energy gains in larval or juvenile stages and (2) if not, are larvae capable of assimilating
exogenous food at all. Our measurements of energetics in larval and juvenile stages show that C. rosaceus larvae accumulate very little if any energy when fed, but stable isotope data indicate that larvae are able to assimilate
some food. Our results are consistent with similar studies on facultative planktotrophic larvae suggesting poor food assimilation
and rapid loss of larval feeding after a population evolves the ability to reach metamorphosis without feeding (lecithotrophy). 相似文献
9.
We examined the effects of elevated temperature under different exposure periods on larval settlement and post-settlement
survival in scleractinian corals, Acropora solitaryensis and Favites chinensis. In the first experiment with the subtropical coral, A. solitaryensis, the numbers of larvae settling and those dead were examined daily for 5 days at 20, 23 (ambient), 26 and 29°C conditions.
Larval settlement of A. solitaryensis was initially greater at higher temperature conditions, but the peak in number of settled larvae shifted from 29 to 26°C
by day 5, due to ca. 90% post-settlement mortality at 29°C condition. In order to determine the effects under short-term exposure,
larvae of F. chinensis were exposed to 27 (ambient), 31 or 34°C only for one hour in the second experiment. The number of larvae settling for 24 h
after the exposure and their survivorship over subsequent week was monitored in the ambient temperature condition. Larvae
of F. chinensis exhibited greater settlement at higher temperature treatments and constantly low post-settlement mortalities (< ca. 17%)
in all temperature treatments, resulting in the highest number of settled larvae at 34°C treatment. These results suggested
two different effects of elevated temperature on the early stages of recruitment process of scleractinian corals; (1) the
positive effect on larval settlement and (2) the negative effect on post-settlement survival under prolonged exposure. 相似文献
10.
Summary. In earlier investigations on host plant discrimination of leaf beetles glucosinolates were described as feeding stimulants
for the Brassicaceae specialist Phaedon cochleariae F. (Coleoptera: Chrysomelidae). However, since these findings could not be confirmed in later studies offering 2-propenylglucosinolate
in concentrations corresponding to those detected in host plant leaf material, the identification of feeding stimulants of
this leaf beetle species remained unclear. In order to investigate which compounds of the host plant Sinapis alba (Brassicaceae) are involved in feeding stimulation, leaf extracts of different polarities were tested in bioassays with adults
of P. cochleariae. Number of feeding beetles and net consumption rates were highest on pea leaves painted with methanol extracts of S. alba, whereas weak feeding responses were also detectable for hexane extracts. In subsequent bioassay-guided fractionations of
methanol extracts with semi-preparative high performance liquid chromatography, two distinct fractions, one containing glucosinolates
and another containing flavonoids, were found to stimulate beetles to feed to variable degrees. Other collected fractions
had zero activity. The combination of both active fractions evoked significantly higher consumption rates and stimulated more
beetles to feed than fractions tested individually. At least one compound of each fraction, among these the main glucosinolate
of S. alba, 4-hydroxybenzylglucosinolate, act additively. Effects of two different naturally-occurring ratios of glucosinolates and
flavonoids on the strength of feeding responses were investigated by use of extracts of two sets of host plants differently
exposed to radiation. One set was outdoors-exposed, whereas the second set was kept in the greenhouse. However, the feeding
behaviour of P. cochleariae was not affected by the significantly different relative compositions of both compound classes in the host material. In conclusion,
mustard leaf beetles need a combination of distinct plant metabolites acting in concert for feeding stimulation, whereby the
mere presence of these stimulants, but probably not the ratio of involved compounds, determines their feeding response. 相似文献
11.
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
12.
While qualitative observations of jellyfish intraguild predation abound in the literature, there are only few rate measurements
of these interactions. We quantified predation rates among two common jellyfish in northern boreal waters, Cyanea capillata and its prey Aurelia aurita, both of which also feed on crustacean zooplankton and fish larvae. A series of incubation experiments using a wide range
of prey concentrations (0.38–3.8 m−3) in large containers (2.6 m3) was carried out. By replenishing the prey continuously as they were captured we maintained a nearly constant prey concentrations.
Ingestion rates increased linearly up to prey concentrations of 1.92 m−3, yielding maximum clearance rates of ∼2.37 ± 0.39 m3 predator−1 h−1 for C. capillata predators 16 ± 2.3 cm in diameter. Mean ingestion rate at saturated prey concentrations (1.92–3.85 m−3) was 4.01 ± 0.78 prey predator−1 h−1. Behavioral observations suggested that predators did not alter their swimming behavior during meals, and thus that feeding
rates were generally handling limited rather than encounter limited. Predators captured more prey than needed, and semi-digested
prey was often discarded when fresh prey was encountered. 相似文献
13.
Howard I. Browman Jeannette Yen David M. Fields Jean-François St-Pierre Anne Berit Skiftesvik 《Marine Biology》2011,158(12):2653-2660
Paraeuchaeta norvegica (8.5 mm total length) and yolk-sac stage Atlantic cod larvae (4 mm total length) (Gadus morhua) larvae were observed in aquaria (3 l of water) using silhouette video photography. This allowed direct observations (and
quantitative measurement) of predator–prey interactions between these two species in 3-dimensions. Tail beats, used by cod
larvae to propel themselves through the viscous fluid environment, also generate signals detectable by mechanoreceptive copepod
predators. When the prey is close enough for detection and successful capture (approximately half a body-length), the copepod
launches an extremely rapid high Reynolds number attack, grabbing the larva around its midsection. While capture itself takes
place in milliseconds, minutes are required to subdue and completely ingest a cod larva. The behavioural observations are
used to estimate the hydrodynamic signal strength of the cod larva’s tail beats and the copepod’s perceptive field for larval
fish prey. Cod larvae are more sensitive to fluid velocity than P. norvegica and also appear capable of distinguishing between the signal generated by a swimming and an attacking copepod. However, the
copepod can lunge at much faster velocities than a yolk-sac cod larva can escape, leading to the larva’s capture. These observations
can serve as input to the predator–prey component of ecosystem models intended to assess the impact of P. norvegica on cod larvae. 相似文献
14.
Migrating feeding aggregations (or fronts) of sea urchins can dramatically alter subtidal seascapes by destructively grazing
macrophytes. While direct effects of urchin fronts on macrophytes (particularly kelps) are well documented, indirect effects
on associated fauna are largely unknown. Secondary aggregations of predators and scavengers form around fronts of Strongylocentrotus droebachiensis in Nova Scotia. We recorded mean densities of the sea stars Asterias spp. (mainly A. rubens) and Henricia sanguinolenta of up to 11.6 and 1.7 individuals 0.25 m−2 along an urchin front over 1 year. For Asterias, mean density at the front was 7 and 15 times greater than in the kelp bed and adjacent barrens, respectively. There was
strong concordance between locations of peak density of urchins and sea stars (Asterias r = 0.98; H. sanguinolenta r = 0.97) along transects across the kelp–barrens interface, indicating that sea star aggregations migrated along with the
urchin front at rates of up to 2.5 m per month. Size–frequency distributions suggest that Asterias at the front were drawn from both the barrens (smaller individuals) and the kelp bed (larger individuals). These sea stars
fed intensively on mussels on kelp holdfasts and in adjacent patches. Urchin grazing may precipitate aggregations of sea stars
and other predators or scavengers by incidentally consuming or damaging mussels and other small invertebrates, and thereby
releasing a strong odor cue. Consumption of protective holdfasts and turf algae by urchins could facilitate feeding by these
consumers, which may obtain a substantial energy subsidy during destructive grazing events. 相似文献
15.
J. D. Salierno J. D. Shields A. Z. Murphy G. E. Hoffman A. S. Kane 《Marine Biology》2007,152(4):835-843
To better understand sublethal effects of harmful algal blooms (HABs) on fish, mummichog, Fundulus heteroclitus (L.), were exposed in the laboratory to varying, environmentally relevant densities of Pfiesteria shumwayae (Glasgow et Burkholder, CCMP 2089, dinoflagellate) and Chaetoceros concavicornis (Mangin, CCMP 169, diatom). Two experiments were conducted during the spring of 2003 and 2004 to quantitatively examine the
effects of acute (2 h) P. shumwayae and C. concavicornis algal exposure on mummichog brain activity using c-Fos expression as a marker of altered neuronal activity. Brains from HAB-exposed
fish were removed, sectioned, and stained using immunocytochemistry prior to quantifying neuronal c-Fos expression. Fish exposed
to P. shumwayae and C. concavicornis showed increased c-Fos expression compared to unexposed control fish. A significant dose-response relationship was observed,
with increased labeling in brains of fish exposed to higher cell densities for both HAB species tested (P ≤ 0.01). Increased labeling was found in the telencephalon, optic lobes, midbrain, and portions of the medulla. The greatest
increases in expression were observed in the telencephalon of P. shumwayae-exposed fish, and in the telencephalon and optic lobes of C. concavicornis-exposed fish (P ≤ 0.01). These increases in c-Fos expression are consistent with other physical and chemical stress exposures observed in
fish. Neuronal stress, evidenced by c-Fos expression, demonstrates a sublethal effect of exposure and changes in brain activity
in fish exposed to HAB species. 相似文献
16.
Fleur E. Champion de Crespigny Nina Wedell 《Behavioral ecology and sociobiology》2007,61(8):1229-1235
The maternally inherited bacterium Wolbachia pipientis generates strong reproductive incompatibilities between uninfected females and infected males (cytoplasmic incompatibility),
significantly reducing both female and male reproductive success. Such fitness costs are thought to place selective pressure
on hosts to evolve pre-copulatory preferences for mating with compatible mates, thereby enabling them to avoid the reproductive
incompatibilities associated with Wolbachia. Therefore, uninfected females are predicted to prefer mating with uninfected males, whereas infected males are predicted
to prefer mating with infected females. Despite these predictions, previous investigations of pre-copulatory mate preferences
in Wolbachia-manipulated Drosophila have not found evidence of female preference for uninfected or compatible males. However, none of these studies utilised
a design where focal individuals are provided with a simple choice in a relatively non-competitive situation. We examined
both female and male pre-copulatory mate preference based on mate infection status in Drosophila simulans and D. melanogaster using simple choice assays involving between 30–50 replicates per treatment. Although we found no evidence of female pre-copulatory
mate preferences in either species, male D. simulans exhibited some preference for mating with females of the same infection status. However, this preference was not evident
when we repeated the experiment to confirm this finding. Consequently, we conclude that neither male nor female D. melanogaster and D. simulans exhibit significant Wolbachia-associated pre-copulatory mate preferences. 相似文献
17.
Andrea Gori Sergio Rossi Elisa Berganzo Joan Lluis Pretus Mark R. T. Dale Josep-Maria Gili 《Marine Biology》2011,158(1):143-158
Most of the current knowledge on Mediterranean gorgonians is restricted to investigations of those populations found within
shallow sublittoral waters, and only limited data are available for populations located below scuba depth. To overcome this
lack of information, the occurrence and abundance of the gorgonians Eunicella singularis, Paramuricea clavata, and Leptogorgia sarmentosa were investigated in northwestern Mediterranean benthic communities over a wide geographical (60 km of coastline) and bathymetrical
(0–70 m deep) extent using a remotely operated vehicle (ROV). The greatest occurrence and abundances of E. singularis and P. clavata were concentrated in areas that are directly exposed to strong near-bottom currents. E. singularis was the most common and abundant species and displayed great plasticity and amplitude in its environmental preferences. Conversely,
P. clavata showed a very patchy distribution that was associated with vertical rocky walls. Only isolated colonies of L. sarmentosa were observed in the study area. Hot spots of abundance of E. singularis and P. clavata were identified below a depth of 40 m, which demonstrates the importance of studying the distribution of benthic species
over a wide geographical and bathymetrical extent. 相似文献
18.
The zoanthid genus Isaurus (Anthozoa: Hexacorallia) is known from both the Indo-Pacific and Atlantic Oceans, but phylogenetic studies examining Isaurus using molecular markers have not yet been conducted. Here, two genes of markers [mitochondrial cytochrome oxidase subunit
I (COI) and mitochondrial 16S ribosomal DNA (mt 16S rDNA)] from Isaurus specimens collected from southern Japan (n = 19) and western Australia (n = 3) were sequenced in order to investigate the molecular phylogenetic position of Isaurus within the order Zoantharia and the family Zoanthidae. Additionally, obtained sequences and morphological data (polyp size,
mesentery numbers, mesogleal thickness) were utilized to examine Isaurus species diversity and morphological variation. By comparing our obtained sequences with the few previously acquired sequences
of genera Isaurus as well as with Zoanthus, Acrozoanthus (both family Zoanthidae), and Palythoa spp. (family Spenophidae) sequences, the phylogenetic position of Isaurus as sister to Zoanthus within the Family Zoanthidae was suggested. Based on genetic data, Isaurus is most closely related to the genus Zoanthus. Despite considerable morphological variation (in particular, polyp length, mesentery numbers, external coloration) between
collected Isaurus specimens, all specimens examined are apparently conspecific or very closely related based on molecular data and observed
morphological variation within colonies. Additionally, obtained internal transcribed spacer of ribosomal DNA (ITS-rDNA) sequences
from symbiotic zooxanthellae (Symbiodinium spp.) from all Isaurus specimens were shown to be subclade C1-related Symbiodinium.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
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
20.
M. A. Iannotta F. P. Patti M. Ambrosino G. Procaccini M. C. Gambi 《Marine Biology》2007,150(6):1115-1126
The aim of this work was to define the phylogeographic patterns of the two species of polychaete Eunicidae, Lysidice ninetta Audouin and Milne Edwards and Lysidice collaris Grube, both associated as sheath borers to the Mediterranean seagrass Posidonia oceanica, and with reference to their different origin and their actual geographic distribution. L. ninetta is distributed in the Atlantic and in the Mediterranean Sea while L. collaris is a tropical species, whose introduction into the Mediterranean Sea through the Suez Canal (lessepsian migrant) has been
hypothesized in recent years. The two species have been often confused in the past, although they appear morphologically distinct.
They share the same microhabitat (Posidonia sheaths) and they co-exist along a broad bathymetric range (1–30 m). Several populations for both taxa were sampled all along
the coast of the Mediterranean basin. A variable no coding region of nuclear DNA (rDNA, ITS1) and a portion of a more conservative
coding region of mitochondrial DNA (sub-unit one of citochrome oxidase, COI) were used as molecular markers. Both markers
confirmed the separation between the two species. Low intraspecific polymorphism was present in L. collaris, together with absence of phylogeographic structure. In L. ninetta, instead, the presence of intraspecific cryptic lineages, sympatric in some sites, was recorded. Clustering of single populations
in the two main clades was not always consistent between markers. The mitochondrial COI region showed more resolution at the
given spatial scale. Our results suggest that Lysidice collaris could be recently introduced into the Mediterranean Sea from one or more separate events. On the other hand, for L. ninetta one could presume a re-colonization of the Mediterranean basin from the Atlantics, after the Messinian crisis (dry-out of
the Mediterranean Sea, 5.5 my) with the subsequent separation of intraspecific lineages. The phylogeographic patterns of both
Lysidice spp. are disjoined with respect to that of the host plant, P. oceanica. The obtained results suggest that environmental constraints and evolutionary history of these polychaetes and their host
plant act in different ways to determine their actual genetic spatial structure. 相似文献