Spatial and foraging behaviour, diet and morphogenesis of postlarvae and juveniles of Pempheris vanicolensis in the Gulf of Aqaba, Red Sea

Post-settlement ecology, ontogenesis of morphology and behaviour were studied in juvenile Pempheris vanicolensis (Pempheridae, Teleostei) in the Gulf of Aqaba, Red Sea. Postflexion larvae of 5.6-6.0 mm total length settled around breakwater heads and natural rocky outcrops of the subtidal zone, widely separated from adults dwelling in groups in coral reef crevices and caves. Settling juveniles formed groups of uniform age and foraged on zooplankton around their habitats. Their circadian behaviour was regulated by levels of illumination in the water, differing slightly in the various age groups. At sunset, juvenile P. vanicolensis migrated and dispersed in deeper water, returning before sunrise to their rocky habitats. Their patterns of foraging and migration behaviours were analysed. At 28.0-32.0 mm total length and 500 mg body weight, the increase in height and length ( H/L ratio) of the juvenile changed from monoto heterochronous, after which a rhomboid body shape, typical for this species, was formed. Concomitantly, the retina of the juvenile changed from a photopic to a scotopic one, the body became heavily pigmented, and the fish left the subtidal rocks, migrating to crevices in coral formations where they settled in close proximity to groups of adult P. vanicolensis .     

Larvae and juveniles of three gobiid species of the genus Priolepis

Ichthyological Research - Larvae and juveniles of three species in the family Gobiidae were described based on reared material; Priolepis borea survived to post-settlement, and Priolepis cincta and...     

Larvae and juveniles of Leptoderma lubricum and L. retropinnum (Argentiformes: Alepocephalidae) collected from Suruga Bay, Japan

Larvae and juveniles of the alepocephalid fishes, Leptoderma lubricum [26.9–69.0 mm in standard length (SL)] and Leptoderma retropinnum (21.1–67.2 mm SL), collected within 1–8 m of the seafloor in Suruga Bay, southern Japan, are described. They can be easily distinguished from each other by the following adult-like characters: membrane morphology between the vertical fin rays and procurrent caudal-fin rays (separated in L. lubricum vs. continuous in L. retropinnum), numbers of dorsal-fin rays (34–40 vs. 45–52) and anal-fin rays (50–57 vs. 65–72), and caudal peduncle length (11.7–13.4% SL vs. 4.5–5.9% SL), in addition to several other body proportional differences. Unique characters in the larval stages of Leptoderma include a translucent occipital region, horizontally elongated eye, and head below the upper margin of the orbit and abdominal cavity densely covered by melanophores, ontogeny being characterized by the acquisition of general adult characters to the postflexion stage, indistinct transformation, and the retention of few larval characters until almost the end of the juvenile stage, as in other known alepocephalids. In addition to the near-bottom larval and juvenile collections of both species, the occurrences of benthic or near-bottom taxa, including Harpacticoida, in their gut contents confirmed the early life history dependence of the former on the near-bottom.     

Larvae and juveniles of blue drum,Nibea mitsukurii,occurring in the surf zone of Tosa Bay,Japan

A total of 211 larval and juvenileNibea mitsukurii (4.0–19.0 mm SL) was collected with a small seine in surf zones of Tosa Bay during the period of May 1981 to June 1984. They had morphological characteristics common to the larvae and juveniles of Sciaenidae, but were distinguished from the others by the distribution pattern of melanophores on body and spines at the anterior tip of maxillary. They occurred only in surf zone of Tei out of three locations facing Tosa Bay from middle May to middle August. Temperatures and salinities at the place when they were collected ranged from 21.7 to 29.5°C and from 24.5 to 31.3‰, respectively. Good catches were observed when minute dusts floated abundantly in the surf zone. In past studies using traditional larval nets or minnow-nets in coastal or shallow waters of Tosa Bay, larval and juvenileN. mitsukurii were not reported. It seems that they occur in association with minute dusts in extremely shallow waters such as surf zones.     

Transitional ecological requirements for early juveniles of two sympatric stichaeid fishes,Cebidichthys violaceus andXiphister mucosus

Synopsis The distribution patterns, diets, and substratum (refuge) requirements of early juveniles of two sympatric stichaeid fishesCebidichthys violaceus andXiphister mucosus, were investigated in a rocky intertidal habitat at Diablo Canyon, California. Monthly investigations were conducted at low tide for four consecutive months, to assess ontogenetic differences in distribution, diet, and refuge requirements within and between the two species. Distinct differences in vertical zonation were exhibited by both stichaeids throughout the study. Interspecific zonation patterns were similar to those recorded for adults of both species. Diet analyses showed that early juveniles of both stichaeids were zooplanktivorous, differing markedly from the primarily herbivorous diets of adults. Changes in diet were largely due to the selection of larger prey taxa as both fishes, and their mouth size, grew over the study period. Predation by both fishes on water-column planktors (calanoid copepods, zoea and polychaete larvae) was greatest following initial intertidal settlement and habitat establishment by early juvenile fishes. Greater dependence on substrate-oriented and/or benthic prey (harpacticoid copepods, gammarid amphipods and mysid shrimp) was exhibited by both fishes as they grew in size. Affinities for sand, gravel, and pebbles during monthly field surveys were similar for both species throughout the study. As the fishes grew, their substratum preferences changed in relation to the substrata which provided the best refuge. Results from laboratory experiments indicated that young stichaeids select very specific substrata based on fish age (size) and substratum suitability (i.e. adequate refuge). Similarities in diet and substratum preferences, and changes in those preferences over time, appear to be the result of morphological similarities (body size and shape and mouth gape) for both species at a given age.     

Consumption of Habenaria sagittifera pollinia by juveniles of the katydid Ducetia japonica

While Habenaria (Orchidaceae) is a species‐rich genus and the orchid diversification is considered to be tightly related to its diverse pollination system, floral visitors of few Habenaria spp. have been studied. Here, we investigated the diurnal floral visitors of Habenaria sagittifera. While Orthoptera have not been considered a regular floral visitor, we observed that juvenile katydid Ducetia japonica (Tettigoniidae) regularly visited and consumed the pollinia and anther caps of H. sagittifera. The relationship between Habenaria and Ducetia would not be a tight mutualism. However, the regular visitation and pollinia consumption may showcase the evolutionary route to Orthoptera–orchid pollination mutualism.     

Development of eggs,larvae and pelagic juveniles of three Indo-Pacific ostraeiid fishes (Tetraodontiformes):Ostracion meleagris,Lactoria fornasini andL. diaphana

The eggs, larvae and pelagic juveniles ofOstracion meleagris, Lactoria fornasini andLactoria diaphana were identified from reared and field collected specimens from Hawaii, Japan, Australia and the eastern Pacific. Eggs are large and pelagic with limited chorion ornamentation and a cluster of oil droplets. At hatching, larvae are well developed, rotund, and enclosed in a dermal sac. The sac disappears and dermal plates form prior to notochord flexion. Larvae of the three species can be distinguished by their pigment patterns and development of the carapace of ossified dermal plates. Eggs of the three species could not be distinguished. The larval stage ends at a small size (< 6 mm) but the juveniles may grow to a substantial size while remaining pelagic.L. diaphana matures and spawns while pelagic in the eastern Pacific.     

Acetate and pyruvate in cell wall polysaccharides ofPropionibacterium acnes,P. avidum,andP. granulosum

Pyruvate and acetate residues were detected in hydrolysates of the cell wall polysaccharides of six strains ofPropionibacterium granulosum, whereas the wall polysaccharides ofP. acnes (three strains) andP. avidum (two strains) contained only acetate. In all strains, acetate appeared to be present only as N-acetyl, since it was alkali resistant.     

Paulownia taiwaniana,a hybrid betweenP. fortunei andP. kawakamii (Scrophulariaceae)

Paulownia taiwaniana, the widely cultivated, commercially important tree, has been suspected of being of hybrid origin at least since its original publication in 1975. Evidence in support of this thesis, derived from a number of different investigations, is presented in this paper.—Strong evidence comes from a controlled pollination study of the two supposed parental species,P. kawakamii andP. fortunei. F₁ seedlings, derived from reciprocal crosses between the suspected parents, exhibited identical banding patterns for a number of enzymes (such as SKDH, GOT, and IDH) withP. taiwaniana, when separated by electrophoresis. Furthermore, comparative morphological studies of trichomes and wood parenchyma patterns between the purported parents andP. taiwaniana reveal that this latter qualitatively exhibits characteristics that combine features of both of the suspected parental types. Biochemically, eight enzyme systems were compared in the three species here under discussion, and, without exception, the electrophoretic banding patterns exhibited byP. taiwaniana represented a combination of the alleles of the other two species. Perhaps the most convincing evidence comes from a genetic analysis of the progeny obtained by selfingP. taiwaniana. Genotypic segregation of the offspring based on a single locus each of SKDH and PGI fit the 1:2:1 hypothesis. Genotypic segregation of the offspring based on two loci each of SP and GOT fit the ratio of 3:6:3:1:2:1. This, taken in conjunction with the other data presented, clearly suggests thatP. taiwaniana is a hybrid involvingP. kawakamii andP. fortunei.     

Hybrid between tetraploidPhaseolus sp. andP. calcaratus Roxb.

1. 1.
   In tetraploidPhaseolus sp. ×P. calcaratus cross, shrivelled but viable seeds were produced. One hybrid was raised but it died within a month. Another hybrid was raised to flowering by artificially culturing the embryos before shrivelling.     
   
   

Macrocyst formation in three dictyostelid species,Dictyostelium monochasioides, Polysphondylium candidum, andP. pseudo-candidum

Macrocyst formation in the sexual cycle was found in three dictyostelid species:Dictyostelium monochasioides, Polysphondylium candidum, andP. pseudo-candidum. Mating tests suggested thatD. monochasioides andP. pseudocandidum were heterothallic andP. candidum was homothallic. The primary walls of macrocysts had partially or fully degenerated, while the inner walls, believed to be tertiary walls, showed an undulate structure.     

Cytological characterization of heterochromatin and rDNA inPinus radiata andP. taeda

Fluorochrome C-banding ofPinus radiata andP. taeda metaphase chromosomes showed many pericentromeric DAPI bands and interstitial CMA bands inP. radiata, and centromeric and interstitial CMA bands inP. taeda. Giemsa C-band patterns differed between the species with centromeric bands inP. radiata but no consistent bands inP. taeda. A karyotype ofP. radiata was developed based on banding patterns that distinguished all but two of the 12 pairs of chromosomes. In situ hybridization (ISH) using probes for high-copy ribosomal DNA (rDNA) showed 10 pairs of 18S–25S sites and two pairs of 5S sites in both species. Most of the sites were interstitial or centromeric.     

Mass-marking of bone tissue of Coregonus lavaretus L. and its potential application to monitoring the spatio-temporal distribution of larvae,fry and juveniles of lacustrine fishes

Mass labelling techniques have great potential for the study of larval fish dynamics in closed habitats (lakes, ponds and flooded quarries). Different methods of mass labelling of bone tissue were tested: bathing in tetracycline solutions with or without osmotic shock, and modification of otolith microstria by temperature, photoperiod or feeding manipulations using different batches of eggs, eleuteroembryos, larvae and prefed fry of Coregonus lavaretus L. from Lake Leman. A short period of immersion with osmotic shock produced better results than longer bathing (6 to 18 h) in low concentration (400 mg 1^–1) tetracycline solutions. At the eyed stage of eggs when otoliths appear, it is possible to use the immersion technique in a hyperosmotic solution (5 to 12% sodium chloride) with 1% tetracycline (as the Hydrochloride or Oxytetracycline). Optimal immersion times (maximal labelling with minimal mortality) were determined as follows: 10 to 15 minutes for eyed eggs, 3.5 min. for eggs just before hatching and eleuteroembryos, 1.5 min. for prefed larvae and less than 1 min. for fry of more than 20 mm total length. Microscopic examination of otoliths and caudal vertebrae from coregonid larvae and juveniles reared for two years has allowed us to determine the effectiveness and persistence of fluorescent tetracycline makers.     

Preparation and regeneration of mycelial protoplasts ofPleurotus florida andP. ostreatus

A method for isolation of higher frequency of regenerated protoplast fromPleurotus florida andP. ostreatus is reported.     

Mate recognition in two sympatric species of butterflies,Pieris rapae andP. melete

Female butterflies should distinguish conspecific males from males of different species. The aim of the present study was to evaluate the female role in avoiding allospecific mating between 2 sympatric pierids,Pieris rapae crucivora (P. rapae hereafter) andP. melete. Since it is relatively rate to observe responses of a wild female to a courting male of different species, we substituted the wings of a female with those of a female of the other species. Such a female attracted allospecific males. FemaleP. melete took “mate-refusal posture” to courting males, regardless whether the male belonged to different species or not. FemaleP. melete discontinued the posture only when the male was conspecific. Such a behavioural difference indicates that the female discriminated its conspecific male. On the other hand, when only the mate-refusal posture was taken into account, a femaleP. rapae did not differently respond to courlship of males of bothP. melete andP. rapae. Having once approached, the maleP. melete attempted more frequently to copulate with its conspecific females than with allospecific ones, while the maleP. rapae indiscriminately attempted to copulate with both allospecific and conspecific females. The maleP. melete tended to persist in its courtship to females of bothP. rapae andP. melete who took the mate-refusal posture. The mate recognition system by male and female in these 2 species is discussed in connexion with the difference in mating behaviour pattern of the species.     

Chromosome analysis and DNA homology in threePicea species,P. mariana,P. rubens,andP. glauca (Pinaceae)

A detailed karyotype analysis was made on the somatic complement ofPicea rubens andP. glauca. B-chromosomes were observed in someP. glauca populations. The karyotypes are generally asymmetrical with most of the chromosomes having median to median-submedian centromeres.Picea glauca chromosomes 2, 3, 7, and 8 have secondary constriction on their short arm and chromosome 10 has a secondary constriction on the long arm. Chromosome 3 was the most easily identifiable, as it has two secondary constrictions located on the short arm. InP. rubens, all the chromosomes but chromosomes 8 and 9 have one to four distinctive secondary constrictions. In general, the diagrammatic comparisons show a high degree of similarity amongP. mariana, P. rubens, andP. glauca. GenomicP. mariana probe strongly hybridized to dots of genomic DNA fromP. rubens andP. glauca indicating that there is a high sequence homology among these three species. The synchronizing agent, hydroxyurea was used at different concentrations to enhance the mitotic index of cell suspensions derived from embryogenic cultures. Hydroxyurea at 1.25 mM increased significantly the mitotic index. An increase of hydroxyurea from 1.25 mM to 5 mM and 10 mM resulted in a steady decrease of mitotic index.     

Induced apogamous sporophytes inPteris dispar andP. semipinnata,and the meiotic behavior in their sporocytes

Spores ofPteris dispar andP. semipinnata were aseptically cultured in flasks for apogamous sporophyte induction. Calli or cell colonies similar to calli were induced in cultures supplemented with hormones. Sporophytic leaves subsequently developed from them in hormone-free medium and the young sporophytes were raised into plants with sporangia. Since the wild-type plants having 116 chromosomes are tetraploid, the sporophytic plants originating from spores would appear to be diploid (dihaploid). In induced sporophytes ofP. semipinnata, non-homologous chromosomes (58 univalents) were found during the meiotic process in sporocytes. InP. dispar, however, the meiotic cells showed many bivalent chromosomes (maximum 29ll). These results suggest thatP. semipinnata is allotetraploid, whereasP. dispar is autotetraploid.