Triterpenoid and caffeic acid derivatives in the leaves of ragweed, <Emphasis Type="Italic">Ambrosia artemisiifolia</Emphasis> L. (Asterales: Asteraceae), as feeding stimulants of <Emphasis Type="Italic">Ophraella communa</Emphasis> LeSage (Coleoptera: Chrysomelidae)

Summary. The leaf beetle Ophraella communa infests almost exclusively Ambrosia artemisiifolia in the fields of Japan, even though it normally feeds on several Asteraceous plants. A filter paper bioassay showed that the feeding of O. communa is strongly stimulated by methanolic extracts of A. artemisiifolia. The feeding stimulants for O. communa have been isolated from methanolic extracts of A. artemisiifolia. -Amyrin acetate, -amyrin acetate, 5-caffeoylquinic acid (chlorogenic acid) and 3,5-dicaffeoylquinic acid from A. artemisiifolia have been identified as feeding stimulants for O. communa. Triterpenoid derivatives (-amyrin acetate or -amyrin acetate) and caffeic acid derivatives (3, 5-dicaffoylquinic acid or 5-caffeoylquinic acid) showed feeding stimulant activity when mixed together.     

Photoperiodic activity pattern in the brittle star<Emphasis Type="Italic"> Amphiura filiformis</Emphasis>

Diurnal activity pattern of suspension-feeding arms of the infaunal brittle star Amphiura filiformis was recorded in situ by time-lapse photography at 30 m water depth in the Gullmarsfjord, west Sweden. Activity was clearly related to the photoperiod with high activity at night and low or no activity during daytime. In laboratory experiments, the activity of the arms of A. filiformis changed in relation to new manipulated photoperiods, demonstrating exogenous circadian rhythms. The time difference for the greatest change in activity of the arms between control and treatment was correlated with the photoperiodicity. The recently found microlenses and associated neural photoreceptors in ophiuroids may apply also to A. filiformis. The trade-off between efficient feeding and predator avoidance is discussed.Communicated by M. Kühl, Helsingør     

Descriptions and durations of premolt setal stages in female Dungeness crabs,<Emphasis Type="Italic"> Cancer magister</Emphasis>

For crustaceans with a well-defined annual molting season, such as adult female Dungeness crabs (Cancer magister Dana), setal molt staging can, in principle, be used to predict molting destiny of individual crabs. Size-specific predictions of molting probability could, in turn, be useful for estimating mortalities due to molting. Female Dungeness crabs were collected January–March 1997 at depths of 10–30 m off the California coast, USA (41°N). Intermolt stage A₁–C₄ and premolt stages D₀, D₁, D₁, D₁ and D₂ were described based on features of the branchial epipod. Laboratory experiments suggested that stage D₁ was the earliest stage beyond which eventual molting was inevitable so that molting destiny could be determined. Estimated mean number of days from the beginning of stage D₁ to molting was 85. Estimated individual stage durations, based on laboratory experiments, were 24, 51, –4, 18, and 20 days, respectively, for stages D₀, D₁, D₁, D₁, and >D₂. The estimated –4 days for stage D₁ suggests that this stage must be very brief and raises a question of its utility in designation of molt stages. Molt staging of three field samples, 300–600 crabs in each, collected prior to the 1997 annual molting season, indicated an increase in the size and frequency of crabs staged D₁ or later as the time to molt approached, although crabs of 150 mm carapace width and larger showed few signs of molt preparation. Because the duration of the molting season (approximately 120 days) for adult female C. magister in northern California exceeds the estimated maximum duration of reliable prediction of molting destiny (85 days), it does not appear that molt staging can be used to predict molting destiny in this population. However, the procedures that we have used in this paper for application to female C. magister might be used with success for other crustaceans if the duration of stages D₁ to molting exceeds the duration of the molting season, and furthermore may be used for describing temporal molting trends.Communicated by J.P. Grassle, New Brunswick     

Habitat and age of the giant squid (<Emphasis Type="Italic">Architeuthis sanctipauli</Emphasis>) inferred from isotopic analyses

The age and habitat of the giant squid, Architeuthis sanctipauli Velain, 1877, were determined based on isotopic analyses of the statoliths of three female specimens captured off Tasmania, Australia, between January and March 1996. Assuming that the aragonite of the statoliths formed in equilibrium with seawater, ¹⁸O analyses indicated that the squid lived at temperatures of 10.5–12.9°C, corresponding to average depths of 125–250 m and maximum depths of 500 m. The capture records indicated that these squid may have occasionally ranged still deeper, to as much as 1000 m. All the statoliths were labeled with bomb ¹⁴C (¹⁴C=+22.9 to +44.6), consistent with the depths inferred from ¹⁸O. A thin section through one of the statoliths revealed 351 growth increments grouped into check-ring structures every 10–16 increments. A model for statolith growth and the pattern of temporal change in ¹⁴C in the water column was used to estimate the ages of the three specimens. These estimates were very sensitive to the choice of depth range over which ¹⁴C values were integrated. Assuming that the capture depths represented the maximum habitat depths of these individuals, the calculations suggested an age of 14 years or less. More refined age estimates require a better understanding of the variation of ¹⁴C and temperature with depth in the areas in which the squids live.Communicated by J.P. Grassle, New Brunswick     

Reproductive effort in relation to maternal social rank in reindeer (<Emphasis Type="Italic">Rangifer tarandus</Emphasis>)

In polygynous mammals, high-quality females may increase their fitness by providing superior care to their offspring. Based on the agonistic interactions of female reindeer in an experimental herd during two consecutive years (1997 and 1998), we tested whether maternal social rank influenced: (1) winter body-mass change of females, (2) preparturition reproductive effort (measured as fecundity, the birth mass and the birth date of their calves), (3) preweaning maternal effort (measured as calves preweaning mortality, early preweaning and late preweaning growth rate and September body mass of calves), and (4) postweaning maternal effort (measured as calves body-mass change during their first winter). In the models, we included September females body mass as a covariate to separate the effects of maternal rank and body mass. We also tested whether the effect of social rank on maternal efforts was dependent on offspring sex. High-ranked females gained body mass whereas low-ranked females lost weight during the winter. Fecundity was higher and date of birth was earlier in high-ranked females than in subordinates, whereas no effect of females rank on birth mass of calves was found. Early preweaning growth rate and September body mass of calves increased with increasing females social rank, whereas late preweaning daily growth rate of calves was not influenced by females rank. Calves preweaning mortality was only influenced by year, which also explained most of the variance in the winter body-mass change of calves. The effects of females rank on the reproductive-efforts parameters studied were not specific to offspring sex. These findings suggest that females rank influences reproductive effort during the preparturition, as well as the preweaning, period, the effect being sex independent.Communicated by R. Gibson     

Ground gleaning in horseshoe bats: comparative evidence from<Emphasis Type="Italic"> Rhinolophus blasii</Emphasis>,<Emphasis Type="Italic"> R. euryale</Emphasis> and<Emphasis Type="Italic"> R. mehelyi</Emphasis>

The 71 species of horseshoe bat (genus Rhinolophus) use echolocation calls with long constant-frequency (CF) components to detect and localize fluttering insects which they seize in aerial captures or glean from foliage. Here we describe ground-gleaning as an additional prey-capture strategy for horseshoe bats. This study presents the first record and experimental evidence for ground-gleaning in the little-studied Blasius horseshoe bat (Rhinolophus blasii). The gleaning bouts in a flight tent included landing, quadrupedal walking and take-off from the ground. The bats emitted echolocation calls continuously during all phases of prey capture. Both spontaneously and in a choice experiment, all six individuals attacked only fluttering insects and never motionless prey. These data suggest that R. blasii performs ground-gleaning largely by relying on the same prey-detection strategy and echolocation behaviour that it and other horseshoe bats use for aerial hawking.We also studied the Mediterranean horseshoe bat (R. euryale) in the flight tent. All four individuals never gleaned prey from the ground, though they appeared to be well able to detect fluttering moths on the ground. It is not known yet whether ground-gleaning plays a role in Mehelys horseshoe bat (R. mehelyi). In a performance test, we measured the ability of these three European species of middle-sized horseshoe bats (R. euryale, R. mehelyi and R. blasii) to take-off from the ground. All were able to take flight even in a confined space; i.e. the willingness to ground-glean in R. blasii is not related to a superior take-off performance. In contrast to ground-gleaning bats of other phylogenetic lineages, R. blasii appears not to be a specialist, but rather shows a remarkable behavioural flexibility in prey-capture strategies and abilities. We suggest that the key innovation of CF echolocation paired with behavioural flexibility in foraging strategies might explain the evolutionary success of Rhinolophus as the second largest genus of bat.Communicated by T. Czeschlik     

Spatial and temporal shifts in stable isotope values of the bottom-dwelling shrimp<Emphasis Type="Italic"> Nauticaris marionis</Emphasis> at the sub-Antarctic archipelago

Spatial and temporal dynamics of carbon and nitrogen stable isotope signatures of the bottom-dwelling caridean shrimp Nauticaris marionis were measured during April and May between 1984 and 2000 in the vicinity of Marion Island (the Prince Edward Islands, Southern Ocean). There was one trophic-level enrichment in bulk ¹⁵N and ¹³C signatures between small (<20 mm long) and large (>20 mm) specimens of N. marionis, suggesting distinct trophic differentiation among major shrimp size groups. Both ¹⁵N and ¹³C values of N. marionis increased with the depth, reflecting changes in their diet. There were no clear temporal trends in bulk ¹⁵N signatures of N. marionis. However, compound-specific ¹⁵N measurements of amino acids indicated that N. marionis from the inter-island realm occupied the trophic level of second order carnivores, while similarly sized shrimps in the near-shore realm were at the trophic level of first order carnivores. Compound-specific measurements also identified a change in the source of inorganic nitrogen at the base of the food web between the inter-island and near-shore realms. In contrast to the bulk ¹⁵N values, a significant shift in bulk ¹³C values of N. marionis was observed between 1984 and more recent years. This temporal change appears to be linked to changes in the overall productivity of the Prince Edward Island inter-island system, which could be linked to global climate change.Communicated by J.P. Thorpe, Port Erin     

Rapid response to changing light environments of the calanoid copepod<Emphasis Type="Italic"> Calanus sinicus</Emphasis>

Calanus sinicus is a large calanoid copepod and a dominant species in the coastal waters of Japan. During a research cruise in Sagami Bay on 18 June 1996, we found C. sinicus performing an unusual diel vertical migration (DVM), a behavior that has not been reported in previous studies on this species. This study examined the DVM of C. sinicus under different light environments and revealed the copepods characteristic response to light. Field and laboratory results show that the DVM of C. sinicus is flexible and also confirmed its sensitivity and its rapid response to changing light environments. It is suggested that C. sinicus reacts to changes in absolute light intensity. This feature may be common in oceanic copepod species. The copepods quick reaction to light variation provides decreased predation risks and increased feeding opportunities, which make them a dominant survivor in coastal water habitats.Communicated by T. Ikeda, Hakodate     

Stability of eelgrass (<Emphasis Type="Italic">Zostera marina</Emphasis> L.) depth limits: influence of habitat type

Seagrass meadows are generally considered stable although few studies have specified and tested this statement. On the basis of a large monitoring dataset from Danish coastal waters, we aimed to test whether the stability of deep eelgrass populations changes along a eutrophication gradient extending from inner bays over outer bays to open coastal waters. We defined stability in terms of the stability properties of constancy, resilience, and/or persistence. Our data allowed us to investigate the stability property constancy expressed as temporal variability in eelgrass depth limits over a time scale of 10 years. We hypothesised that colonisation depths were large and relatively constant along open coasts because of low and relatively constant levels of nutrients and turbidity. Conversely, colonisation depths were hypothesised to be low and variable in protected bays due to higher and more variable levels of nutrients and turbidity. We found that depth limits increased from inner bays towards open coastal waters, matching declines in nutrient concentration and increases in water clarity and oxygen concentration. Stability expressed as constancy of depth limits did not differ significantly between habitat types, and neither did stability of physicochemical variables. However, when data from all habitat types were analysed together, they showed that eelgrass populations at the depth limit were significantly more constant and thus, in this respect, more stable when occurring in deep waters as compared to shallow waters. Areas of good water quality may thus obtain the double benefit of deeper-growing and more stable eelgrass populations. The most likely reason why this pattern did not appear at habitat-type level is that the habitat types studied represented wide spatial variation in water quality and depth limit. We conclude that the question of whether eelgrass populations are stable depends on the stability property and the ecological situation in question. Populations may be considered unstable in terms of inter-annual variation but stable in terms of long-term persistence. Therefore, the common statement that eelgrass populations are stable is not universally true.Communicated by M. Kühl, Helsingør     

Proclivity and effectiveness in gall defence by soldiers in five species of gall-inducing thrips: benefits of morphological caste dimorphism in two species (<Emphasis Type="Italic">Kladothrips intermedius</Emphasis> and<Emphasis Type="Italic"> K. habrus</Emphasis>)

The essence of eusociality is a trade-off between producing ones own offspring and helping collateral kin via such activities as defence, foraging and brood rearing. This trade-off often involves morphological differences between helper and reproductive castes, but the advantages, correlates and phylogenetic context of morphological caste differentiation have seldom been analysed. Six species of Australian gall-inducing thrips on Acacia show morphological polymorphism. One morph, referred to as a soldier, has reduced wings and antennae but greatly enlarged fore-femora, which are thought to be adaptations for gall defence. The other, dispersing morph, has fully developed wings and relatively slight fore-femora. Here, we quantify the defensive behaviour of soldier morphs, and compare soldier and foundresses, using behavioural assays designed to measure proclivity to attack kleptoparasites (specialised invaders in the genus Koptothrips) and effectiveness in killing them. In all five species investigated, soldiers were able to kill Koptothrips. Moreover, the effectiveness of soldiers was relatively high in the more-derived species in the phylogeny of the clade, Kladothrips intermedius, K. habrus and K. waterhousei. Soldiers of K. intermedius and K. habrus also killed kleptoparasites more effectively than did foundresses, and K. habrus soldiers exhibited higher proclivity to attack than did foundresses. Data from naturally invaded galls demonstrate that soldiers in the field do kill Koptothrips, and vice versa. These results show that soldiers of Australian gall thrips are motivated and effective for gall defence.Communicated by D. Gwynne     

Sperm utilization pattern in the honeybee (<Emphasis Type="Italic">Apis mellifera</Emphasis>)

Queen honeybees (Apis mellifera) mate with a large number of drones on their nuptial flights. Not all drones contribute equally to the queens offspring and the queens utilization pattern of spermatozoa from different drones has an important impact on the genetic composition of the colony. Here we study the consequences of sperm use for the fitness of the queens mates with microsatellite DNA-fingerprinting. Eight queens were instrumentally inseminated with semen of six or seven drones. Each drone contributed either 0.5 µl or 1.0 µl semen, respectively, and we analyzed both the impact of the insemination sequence and the amount of semen on the sperm utilization. Our data show no significant effect of the insemination sequence but a strong impact of the semen volume of a drone on the frequency of his worker offspring in the colony. This effect was not linear and the patriline frequencies of the drones contributing larger semen volumes are disproportionately enhanced. If these observations are also valid for natural matings, drone honeybees should maximize the number of sperm but not apply specific mating tactics to be first or last male in a mating sequence.Communicated by R. PageAn erratum to this article can be found at     

Sources of carbon and dietary habits of new Lessepsian entry<Emphasis Type="Italic"> Brachidontes pharaonis</Emphasis> (Bivalvia,Mytilidae) in the western Mediterranean

The sources of carbon and the dietary habits of Brachidontes pharaonis (Mollusca, Bivalvia), a new Lessepsian entry in the western Mediterranean, living in a cooling vat of a saltworks system in western Sicily (MED), were assessed by estimating throughout a season the relative abundance of a stable carbon isotope (¹³C) in particulate organic matter (POM), sedimentary organic matter (SOM), primary organic matter sources (seagrasses, sand microflora, macroalgae), Brachidontes pharaonis and its biodeposition material. In the saltworks the most enriched primary food source potentially fuelling the saltworks food web was Cymodocea nodosa (seasonal average –7.9±0.6), Laurencia papillosa and Cystoseira sp., which represented the predominant macroalgae (seasonal average –19.0±1.0) and sand microflora ¹³C (–14.7±0.11). POM annual mean ¹³C was –17.4±0.9, and that of SOM was –17.0±2.3. The seasonal mean isotopic value of B. pharaonis was –14.7±0.7; while its faeces was more depleted (–17.7±2.4), while the pseudofaeces (–14.6±3.6) was similar to somatic B. pharaonis in composition. Our study showed that Brachidontes assimilated mostly mixed sedimentary organic carbon re-arranged via a detritus route dominated mainly by macroalgae and sand microflora and that it was able to exploit almost all the predominant carbon sources available in its colonised environment both directly (sand microflora) and indirectly via the POM/SOM detritus route. These carbon sources incorporated most of the environmental variability relative to the isotopic composition of primary producers (about –11 throughout the year).Communicated by R. Cattaneo-Vietti, Genova     

Nuclear and mitochondrial DNA markers indicate unidirectional gene flow of Indo-Pacific to Atlantic bigeye tuna (<Emphasis Type="Italic">Thunnus obesus</Emphasis>) populations,and their admixture off southern Africa

A sharp genetic break separates Atlantic from Indo-Pacific bigeye tuna (Thunnus obesus) populations, as the frequencies of two major mitochondrial (mt) DNA types ( and ) found in this species are different across the tip of southern Africa. The level of nucleotide divergence between mtDNA types and is of the same order as that between reproductively isolated taxa. To further investigate the genetic structure of bigeye tuna over its distribution range and in the contact zone off southern Africa, bigeye tuna samples collected between 1992 and 2001 (including samples from a previous mtDNA survey) were characterized for four nuclear DNA loci and for mtDNA. Nuclear markers did not support the hypothesis that and mitochondria characterize sibling species. Significant allele-frequency differences at one intronic locus (GH2) and one microsatellite locus (µ208) were found between Atlantic and Indo-Pacific samples, although the level of nuclear genetic differentiation (Weir and Cockerhams =0.025 to 0.042) was much lower than in mtDNA ( =0.664 to 0.807). Probabilistic Bayesian assignment of individuals to a population confirmed that southern African bigeye tuna samples represent a simple mixture of individuals from Atlantic and Indian stocks that do not interbreed, with a higher contribution from Indian Ocean individuals (about 2/3 vs. 1/3).Communicated by M.S. Johnson, Crawley     

Reproductive cycle of the endemic cassiduloid<Emphasis Type="Italic"> Cassidulus mitis</Emphasis> (Echinoidea: Cassiduloida) on the Brazilian coast

Cassidulus mitis Krau, 1954 is an endemic species from Rio de Janeiro, Brazil. To study the reproductive cycle of this species, samples were collected at Praia Vermelha, in Guanabara Bay, from October 1998 to April 2000. The sex ratio for C. mitis was 1:1, and reproduction occurred throughout the year. The gonadal index of males was greater than that of females. Five gametogenic stages were identified in males: early growth, premature, mature, partially spawned and early growth with a partially spawned stage. There were no spent or recovery stages such as those seen in females. Females had six gametogenic stages: recovery, early growth, premature, mature, partially spawned and spent stage; there was no early growth with a partially spawned stage as there was in males. The mean oocyte diameter was 382 m (SD=49 m), and the mean number of juveniles per female was 100 individuals (SD=108). The anterior gonads were frequently smaller than the posterior ones, and there were differences in the gametogenic stages between the anterior and posterior gonads. First sexual maturation occurred in individuals with a diameter of 17 mm. The intestinal wet weight was two- to threefold higher than the test wet weight. This may indicate that C. mitis uses its intestine as a weight belt to avoid displacement from the substratum.Communicated by P.W. Sammarco, Chauvin     

Precision and accuracy of stable isotope signals in otoliths of pen-reared cod (<Emphasis Type="Italic">Gadus morhua</Emphasis>) when sampled with a high-resolution micromill

A high-resolution sampling technique for stable-isotope measurements in otoliths is now available, but little is known about the precision and accuracy of the results when using this technique. Otolith samples of pen-reared cod (Gadus morhua L.) with well-defined temperature history were obtained using this high-resolution sampling technique. Samples from different-aged cod otoliths were collected in two yearly increments corresponding to the calendar years 1994 and 1995, and the stable-oxygen (¹⁸O) and -carbon (¹³C) isotope compositions of the samples were measured. Otolith ¹⁸O values had a clear seasonal pattern in response to the seasonal water temperature. Otolith material deposited in the same calendar years of different-aged fish showed similar ¹⁸O values. High precision of the temperature estimate using otolith ¹⁸O values was obtained when comparing results from different otoliths. The accuracy of the temperature estimates, relative to measured mean monthly water temperature, was also high, but reduced sampling resolution in the otoliths significantly reduced the accuracy due to attenuation of the ¹⁸O signals. We found that the otolith ¹³C values had a cyclic pattern, roughly in phase with the ¹⁸O values. This was most likely caused by temperature-increased metabolism. Indications of age-specific otolith ¹³C values are also presented.Communicated by M. Kühl, Helsingør     

Diet and trophic position of Atlantic bluefin tuna (<Emphasis Type="Italic">Thunnus thynnus</Emphasis>) inferred from stable carbon and nitrogen isotope analysis

Stable ¹³C and ¹⁵N isotope analyses of scale, bone, and muscle tissues were used to investigate diet and trophic position of North Atlantic bluefin tuna (Thunnus thynnus Linnaeus) during residency in the northwest Atlantic Ocean off the northeast coast of the United States. Adult bluefin tuna scales collected from fish between June and October 2001 were significantly enriched in ¹³C compared to both muscle and bone across all months, while muscle was significantly enriched in ¹⁵N compared to either bone or scale throughout the same period. In muscle tissue, there was evidence of a shift over the summer from prey with ¹³C values (–17 to –18) that were characteristic of silver hake (Merluccius bilinearis) to species with ¹³C values of –20 to –21 that were similar to Atlantic herring (Clupea harengus) and sandlance (Ammodytes americanus). Depletion of ¹⁵N values in adult scales and bone compared to muscle tissue may be explained by bone and scale samples representing juvenile or life-long feeding habits, isotopic routing, or isotopic differences in amino acid composition of the three tissue types. Adult bluefin tuna were estimated to be feeding at a trophic position similar to pelagic sharks in the northwest Atlantic Ocean, while the trophic positions of yellowfin tuna (Thunnus albacares), albacore tuna (Thunnus alalunga), and juvenile bluefin tuna were indicative of a diet of up to a full trophic position below adult bluefin tuna. The close relationship between the juvenile bluefin ¹⁵N values and those of suspension feeders suggests that nektonic crustaceans or zooplankton may contribute significantly to the diet of bluefin tuna, a food source previously overlooked for this species in the northwest Atlantic Ocean.Communicated by J.P. Grassle, New Brunswick     

Sexual reproduction of the solitary sunset cup coral<Emphasis Type="Italic"> Leptopsammia pruvoti</Emphasis> (Scleractinia: Dendrophylliidae) in the Mediterranean. 1. Morphological aspects of gametogenesis and ontogenesis

Information on the reproduction in scleractinian solitary corals and in those living in temperate zones is notably scant. Leptopsammia pruvoti is a solitary coral living in the Mediterranean Sea and along Atlantic coasts from Portugal to southern England. This coral lives in shaded habitats, from the surface to 70 m in depth, reaching population densities of >17,000 individuals m^–2. In this paper, we discuss the morphological aspects of sexual reproduction in this species. In a separate paper, we report the quantitative data on the annual reproductive cycle and make an interspecific comparison of reproductive traits among Dendrophylliidae aimed at defining different reproductive strategies. The present study on L. pruvoti is the first in-depth investigation of the reproductive biology of a species of this genus. As expected for a member of the family Dendrophylliidae, L. pruvoti is a gonochoric and brooding coral. The gastrodermal tissue of the gametogenetic mesenteries we examined was swollen and granular, which led us to hypothesize that interstitial cells could have a trophic function favoring gametogenesis. Undifferentiated germ cells arose in the gastrodermis and subsequently migrated to the mesoglea, where they completed gametogenesis. During spermary development, spermary diameter increased from a minimum of 14 m during the immature stages to a maximum of 410 m during the mature stages. As oogenesis progressed, we observed a gradual reduction in the nucleus to cytoplasm ratio due to the steady synthesis of yolk. During the final stages of oogenesis, after having migrated to the extreme periphery of the oocyte and having firmly adhered to the oolemma, the nucleus became indented, assuming a sickle or dome shape. We can hypothesize that the nucleus migration and change of shape may have to do with facilitating fertilization and determining the future embryonic axis. During oogenesis, oocyte diameter increased from a minimum of 20 m during the immature stage to a maximum of 680 m when mature. Embryogenesis took place in the coelenteron. We did not see any evidence that even hinted at the formation of a blastocoel; embryonic development proceeded via stereoblastulae with superficial cleavage. Gastrulation took place by delamination. Early and late embryos had diameters of 204–724 m and 290–736 m, respectively. When released, the larvae had completed ontogenesis and swam by a ciliary movement with the aboral pole at the anterior, their shape varied from spherical to cylindrical (in the latter the oral–aboral axis measured 695–1,595 m and the transversal one measured 267–633 m).Communicated by R. Cattaneo-Vietti, Genova     

Competitive interactions between two fucoid algae with different growth forms,<Emphasis Type="Italic"> Fucus serratus</Emphasis> and<Emphasis Type="Italic"> Himanthalia elongata</Emphasis>

Competitive interactions between two fucoid algae with different growth forms, Fucus serratus L. and Himanthalia elongata (L.) S.F. Gray were examined both in the laboratory and on a shore of the Isle of Man, Irish Sea. The growth of germlings of both species declined with increasing density, irrespective of whether they were with cohorts or rival species, indicating that intra- and interspecific competition occurred between germlings. H. elongata suppressed the performance of F. serratus at the germling stage by virtue of its larger initial size, and at the mushroom stage by forming a miniature canopy with the caps of the adjacent plants. In a field experiment, the mortality of H. elongata juveniles generally increased in mixtures with F. serratus and was highest when F. serratus were 50% of the plants. At the juvenile stage, the negative effect of F. serratus on H. elongata was more severe than the other way round. This was because F. serratus grows predominantly upwards, whereas H. elongata had already begun to expand laterally at the distal end. If F. serratus survives in sparse mixed stands with H. elongata juveniles, it can overgrow them and inhibit their subsequent survivorship and growth, probably by both shading and physical sweeping. H. elongata and F. serratus maintain their discrete monospecific stands because of the varying outcomes of mutual competitive exclusion resulting from their differing growth patterns. Thus it is possible for them to co-occur at a similar shore height.Communicated by O. Kinne, Oldendorf/Luhe     

Ancient divergences and recent connections in two tropical Atlantic reef fishes<Emphasis Type="Italic"> Epinephelus adscensionis</Emphasis> and<Emphasis Type="Italic"> Rypticus saponaceous</Emphasis> (Percoidei: Serranidae)

Reef habitats of the tropical Atlantic are separated by river outflows and oceanic expanses that may preclude larval dispersal or other population connections in shorefishes. To examine the impact of these habitat discontinuities on the intraspecific phylogeography of reef-associated species we conducted range-wide surveys of two amphi-Atlantic reef fishes that have dispersive pelagic larval stages. Based on 593 bp of mtDNA cytochrome b from the rock hind Epinephelus adscensionis and 682 bp from the greater soapfish Rypticus saponaceous (n=109 and 86, respectively), we found evidence of relatively ancient separations as well as recent surmounting of biogeographic barriers by dispersal or colonization. Rock hind showed slight but significant population genetic differentiation across much of the tropical Atlantic Ocean (_ST=0.056), but deep divergence between the southeastern United States and seven other localities from the Bahamas to the south, central and east Atlantic (mean pairwise d=0.040, overall _ST=0.867). The geographic distribution of the two rock hind lineages is highly unusual in genetic studies of Caribbean Sea reef fishes, because those lineages are separated by less than 250 km of open water within a major biogeographic region. In contrast, highly significant population genetic structure was observed among greater soapfish from the SW Caribbean, Brazil, and mid-Atlantic ridge (_ST=0.372), with a deep evolutionary separation distinguishing putative R. saponaceous from West Africa (mean pairwise d=0.044, overall _ST=0.929). Both species show evidence for a potential connection between the Caribbean and Brazilian provinces. While widespread haplotype sharing in rock hind indicates that larvae of this species cross oceanic expanses of as much as 2000 km, such a situation is difficult to reconcile with the isolation of populations in Florida and the Bahamas separated by only 250 km. These findings indicate that populations of some species in disjunct biogeographic zones may be isolated for long periods, perhaps sufficient for allopatric speciation, but rare gene flow between zones may preclude such evolutionary divergence in other species.Communicated by P.W. Sammarco, Chauvin     

“Copper” granules in the barnacle Balanus balanoides

Balanus balanoides (L.) collected from an area with high heavy-metal run-off contained two different types of granule within the parenchyma cells of the prosoma. X-ray microprobe analysis shows one to be the familiar zinc granule made up of concentric layers and giving major peaks for phosphorus and zinc, and the other to be homogeneous and giving peaks for sulphur and copper. This latter granule is designated the copper granule. Whilst zinc granules are known to be composed of inorganic phosphate, various tests on copper granules in sections and in a granule-rich pellet have shown that the copper is probably complexed with organic matter. The tests also demonstrated the relatively, insoluble (inert) nature of these granules. Although zinc and copper granules were present together in the prosoma, atomic absorption analyses of whole bodies (prosoma+thorax) have shown the level of zinc (50.28 g/mg dry weight) to be much higher than that of copper (3.75 g/mg dry weight).