An historical overview of the Republic of Ireland's lobster (Homarus gammarus Linnaeus) fishery,with reference to European and North American (Homarus americanus Milne Edwards) lobster landings

Historical developments of the Republic of Ireland's Homarus gammarus fishery are reviewed and compared in the context of landings in Europe and the North American H. americanus fishery. H. gammarus fishing has provided essential income for over a century to many Irish coastal communities. There have been significant fluctuations (greater than 460%) in recorded landings over this time and the relative importance of H. gammarus fishing has changed with the establishment of ancillary crustacean fisheries. In 1994, H. gammarus landings reached an all-time high of 714 tonnes, with a landed value of IR £6.3 million; in 1999 landings were 597 tonnes valued at IR £6.15 million. Current Republic of Ireland lobster fishery regulations are: (a) minimum carapace length of 85 mm, (b) ban on landing lobsters that have been `V-notched' or have a mutilated tail fan, and (c) prohibition of capturing lobsters by SCUBA diving. Chronological details on recent legislation, regulations and landings relating to Ireland's lobster fishery sector are reviewed. In the last 40 years landings of H. gammarus in the Republic of Ireland exhibit signs of an overexploited stock characterised by a reduction in catch per unit effort and there has been a general decline of total landings for H. gammarus throughout Europe. This contrasts with North America, where many regulations govern the H. americanus fishery and landings appear to be in a healthier state.     

Evolution of carotenoid metabolic capabilities during the early development of the European lobster Homarus gammarus (Linné, 1758)

The quantification of carotenoids during the early developmental stages of the European lobster Homarus gammarus, indicates a rapid decrease of pigment concentration, occurring immediately after hatching. Conversely, the carotenoid amount of the individual increases progressively at the end of larval stage I, as a result of an enhanced feeding activity. Free astaxanthin represents the bulk of carotenoids of the unhatched embryo (metanauplius), whereas larval, post-larval and juvenile stages exhibit the typical adult carotenoid pattern, in which astaxanthin esterified forms (diester and monoester) appear preponderant. The Artemia strain used as food material is not found to contain astaxanthin, while important amounts of canthaxanthin are observed; nevertheless, this carotenoid is not detected in the larvae, indicating that metabolic transformation capabilities are already occurring in freshly hatched individuals.     

Cellular organization of the embryonic lobster heart

Summary The cellular organization of the embryonic heart of the lobster Homarus americanus was examined in 6-week and 6-month-old animals. The heart wall consists of an outer adventitial layer of fibroblast cells and an inner layer of transversely striated myocardial cells. Present in close association with the myocardium are cardiac neurons, hemocytes and so-called storage cells.Adjacent fibroblasts form fasciae adhaerentes and gap junctions. Adherent junctions also occur between fibroblasts and myocardial cells. Intercalated discs and differentiated membrane regions of close apposition (4 nm) occur between adjacent myocardial cells.The cardiac neurons form a ganglion that contains four small and five large somata. Regions of neuropil are present. Motor axons arising from the cardiac ganglion form neuromuscular synapses with the myocardial cells.The storage cells contain large inclusions and form gap junctions with the myocardial cells. They may supply nutritive material to the developing myocardium.The heart at 6 weeks is about 200 m long and 160 m wide. At 6 months, it is about 300 m long and 250 m wide. The myocardium at 6 weeks is one cell layer thick, and the cells are from 2–6 m in maximum width. At 6 months the myocardium is 2–4 cells thick, and the cells are from 6–12 m in width. Therefore, the myocardium grows by an increase in the number and size of the myocardial cells.     

Mitotic and meiotic chromosomes of the American lobster Homarus americanus (Nephropidae, Decapoda)

The chromosomes of H. americanus have been characterised by C-banding, fluorochrome banding and restriction endonuclease banding. Thanks to these techniques, it has been possible to identify mitotic and meiotic figures clearly and to study the distribution and structure of heterochromatic regions. Moreover, we have identified small supernumerary chromosomes, variable in number and often asynaptic in first meiotic metaphase.     

Behavioral thermoregulation in the spiny lobster Panulirus Argus (latreille)

Ten spiny lobsters (Panulirus argus) were allowed to thermoregulate individually for 3-day periods in an electronic thermoregulatory shuttlebox which allowed them to control water temperatures (and thereby their own body temperatures) by their movements. The range of preferred (voluntarily occupied) temperatures was 25–35°C (mean 29.9°C; mode 30.0°C; median 30.0°C; midpoint 30.0°C; S_k (skewness, Pearson's coefficient) –0.04; s.e.m. 0.19°C; S.D. 2.32°C). The final thermal preferendum (by the gravitation method) in this species is 30°C.     

Sublethal effects of esfenvalerate residues on pyrethroid resistant Typhlodromus pyri (Acari: Phytoseiidae) and its prey Panonychus ulmi and Tetranychus urticae (Acari: Tetranychidae)

The effect of residues of esfenvalerate on oviposition of the resistant strain of the predatory mite Typhlodromus pyri and its main prey, European red mite Panonychus ulmi and two-spotted spider mite Tetranychus urticae, were investigated. T. pyri showed a significant linear reduction in oviposition after 24h in the presence of increasing levels of esfenvalerate residue applied at the field rate. Furthermore, when given a choice, T. pyri preferred to lay eggs on residue-free surfaces. Of the two prey species, only P. ulmi showed significant avoidance of increasing levels of residues of the field rate concentration of esfenvalerate, as measured by runoff mortality, however both P. ulmi and T. urticae, when given a choice, showed a preference for esfenvalerate-free surfaces. As with the predatory mite T. pyri, both prey species showed a significant linear reduction of oviposition with increasing esfenvalerate residues and a preference to lay eggs on esfenvalerate-free surfaces. Esfenvalerate residues as high as 15X field rate were not repellent to pyrethroid-resistant T. pyri. The possible effects of these sublethal effects on predator-prey dynamics and implications for integrated mite control programmes in apple orchards are discussed.     

Effects of marine reserve protection on spiny lobster (Palinurus elephas Fabr., 1787) in a central western Mediterranean area

The contribution that a small restocking area (central western Mediterranean) has made to the Palinurus elephas (Fabr., 1787) population was examined by comparing the abundances recorded inside and outside the area before (1997) and after the establishment of the reserve (1998–2005). From 1998 to 2002 a progressive percentage increase of P. elephas biomass values was recorded both inside the area and in the surrounding zones. The total mean abundance within the reserve (CPUE = 0.23 ± 0.10 kg/50 m/boat) was 7.5 times greater than that for the neighbouring zone (CPUE = 0.03 ± 0.07 kg/50 m/boat). The inter-annual analysis of lobster size inside the area also showed a progressive increase of adults and juveniles. The results highlighted the effectiveness of fishing restrictions in rebuilding the lobsters population and suggest that small MPAs should be set up. Guest editors: J. Davenport, G. Burnell, T. Cross, M. Emmerson, R. McAllen, R. Ramsay & E. Rogan Challenges to Marine Ecosystems     

Carotenoids in the outer cell-wall layer of Scenedesmus (Chlorophyceae)

Scenedesmus obliquus, strain 633, which synthesizes ketocarotenoids and sporopollenin, also forms pink-red-colored cell walls. Both the cell walls left over after autospore liberation and those from homogenates of disrupted green cells have similar carotenoid pigmentation. Canthaxanthin, astaxanthin, an unidentified ketocarotenoid, and lutein were found as integral cell wall components. They are bound to the outer (trilaminar) layer of the complete cell wall which also contains sporopollenin.Abbreviations CWH complete cell walls isolated from the homogenates - CWM maternal cell walls accumulated in the medium - KC ketocarotenoid - SC secondary carotenoids - SP sporopollenin     

Phase Maintenance in the Pyloric Pattern of the Lobster (Panulirus interruptus) Stomatogastric Ganglion

The extent to which individual neural networks can producephase-constant motor patterns as cycle frequency is altered has notbeen studied extensively. I investigated this issue in thewell-defined, rhythmic pyloric neural network. When pyloric cyclefrequency is altered three- to fivefold, pyloric inter-neuronaldelays shift by hundreds to thousands of msec, and all pyloricpattern elements show strong phase maintenance. The experimentalparadigm used is unlikely to activate exogenous inputs to thenetwork, and these delay changes are thus likely to arise fromphase-compensatory mechanisms intrinsic to the network. Pyloricinter-neuronal delays depend on the time constants of the networkssynapses and of the membrane properties of its neurons. The observeddelay shifts thus suggest that, in response to changes in overallcycle frequency, these constants vary so as to maintain patternphasing.     

The Rhizobium meliloti early nodulation genes (nodABC) are nitrogen-regulated: Isolation of a mutant strain with efficient nodulation capacity on alfalfa in the presence of ammonium

Summary The presence of combined nitrogen in the soil suppresses the formation of nitrogen-fixing root nodules by Rhizobium. We demonstrate that bacterial genes determining early nodulation functions (nodABC) as well as the regulatory gene nodD3 are under nitrogen (NH ₄ ⁺ ) control. Our results suggest that the gene product of nodD3 has a role in mediating the ammonia regulation of early nod genes. The general nitrogen regulatory (ntr) system as well as a chromosomal locus mutated in Rhizobium meliloti were also found to be involved in the regulation of nod gene expression. A R. meliloti mutant with altered sensitivity to ammonia regulation was isolated, capable of more efficient nodulation of alfalfa than the wild-type strain in the presence of 2 mM ammonium sulfate.     

Chloroplast DNA study of the generaAmbrosia s.l. andHymenoclea (Asteraceae): Systematic implications

The relationship ofAmbrosia (ragweed) andFranseria has long been debated. Their treatment as separate genera has been repeatedly challenged. In this study, chloroplast DNA restriction site variation was examined for species from bothAmbrosia andFranseria as well as taxa from the closely related genusHymenoclea. The chloroplast genomes of members of these three genera were examined using 21 restriction endonucleases and the restriction mutations were used to construct phylogenetic trees. Wagner and Dollo parsimony as well as weighted parsimony were employed to compare the different phylogenies. The results support a close relationship betweenAmbrosia andFranseria, but indicate that the two groups are well separated. Compared toFranseria, Ambrosia is a much more strongly supported group, and the results indicate thatHymenoclea is closer toFranseria than toAmbrosia. The cpDNA phylogeny was used as a framework to examine evolutionary trends in morphology and secondary chemistry.     

Oriole pollination ofErythrina breviflora (Leguminosae): Evidence for a polytypic view of ornithophily

Erythrina breviflora is visited by large numbers of passerine birds of which orioles (Icterus: Icteridae) are the primary pollinators. The flowers produce large quantities of nectar but they are rarely visited by hummingbirds. Inflorescence and floral morphology, and low levels of sucrose in the nectar probably explain the rarity of foraging hummingbirds. A comparison of Old WorldErythrina and their pollinators with New World species pollinated by orioles and hummingbirds suggests that parallel evolution has occurred. When the comparison is expanded to include other species pollinated by orioles, it is clear that various New WorldIcteridae, Thraupidae, etc. are ecological equivalents of Old WorldOriolidae, Pycnonotidae, Sturnidae, etc. and that flowers pollinated by these birds have similar characteristics.     

Population Biology of Maculinea rebeli (Lepidoptera: Lycaenidae) on the Chalk Grasslands of Eastern Westphalia (Germany) and Implications for Conservation

The population biology of Maculinea rebeli Hirschke, 1904, on dry grassland biotypes in different successional stages was investigated in the summers of 1990 and 1991 in the district of Höxter (North Rhine–Westphalia, Germany). The population characteristics of M. rebeli were studied by mark-recapture and eggshell counts on the larval host plant Gentiana cruciata. Pitfall traps, ant baits, excavating and counting of ant nests were used to examine the Formicidae community and the nest density of Myrmica sabuleti. In 1990, the total population of M. rebeli was estimated as 528 individuals, with subpopulations varying from 2 to 273 individuals. Populations existed in areas differing in size and vegetation structure. However, the limiting factor for population size was the density of the host ant population. The differences in population size did not depend on the size of the habitat or the density of the larval food plant. The butterflies can switch their host. In the absence of M. schenki, the colonies of M. sabuleti can maintain M. rebeli populations. Adult males and females have a maximum life expectancy of 13 days. The females prefer to oviposit on G. cruciata plants of 10–30cm height. Only plants which stuck out of the surrounding vegetation were oviposited on. The average number of eggs deposited per female was 100–150. Low density populations are probably most threatened. Therefore, future protective measures should work towards further maintaining and optimizing the habitats of the small populations, as well as creating the prerequisites so that dense stable populations of M. rebeli can develop.     

Cranial morphology of the golden monkey (Rhinopithecus) and douc langur (Pygathrix nemaeus)

Because they have been less studied than most other non-human primates (partly due to the difficulties in accessing their habitat) the origins and phylogenetic relationships ofR. roxellana andR. bieti are controversial. These controversies may be clarified to some degree by adding information on the cranium. To this end, ten cranial dimensions analysed morphometrically here provide data about cranial differences among species of the genusRhinopithecus, and between species ofRhinopithecus andPygathrix nemaeus. Though more similar to each other than to any others in the same genus, the results show a significant separation betweenR. roxellana andR. bieti to the degree that they may be regarded as two different species. This confirms the conclusions of prior studies of external features, qualitative morphological characteristics and biochemical evidence (Yeet al, 1987; Zhang and Ryder, 1995; Jablonski, 1998; Penget al., 1988). The differences between these two species are mainly size-related, being highly correlated with cranial length. Other differences, probably non-size related shape differences, however, are highly correlated with cranial width. Sexual dimorphism plays a part in these findings. In relation to the other species, however, the results show that the Vietnam golden monkey (R. avunculus) has closer craniometric relationships with the douc langur (Pygathrix nemaeus) rather than with the three Chinese golden monkey species. Of these, the Gouzhou species (R. brelichi) shares more similarity withR. avunculus and is more separate fromRhinopithecus roxellana and R. bieti. The smaller differentiation between the two latter species could be due to their more recent separation following the dramatic elevation of Qinghai-Tibetan Plateau after the Middle Pleistocene.     

The presence of opioidergic pinealocytes in the pineal gland of the European hamster (Cricetus cricetus): an immunocytochemical study

By use of antibodies raised against leu-enkephalin and met-enkephalin immunoreactive, opioidergic bi- and multipolar cells were demonstrated in the pineal gland of the European hamster. Ultrastructural analysis of these opioidergic cells revealed them to be pinealocytes. Processes emerged from the cell bodies and terminated in club-shaped swellings containing many small clear and some larger granular vesicles. Some of the terminals made synapse-like contacts with non-immunoreactive pinealocytes. The presence of the opioidergic pinealocytes strongly indicates that the pineal gland of the European hamster, in addition to its pinealopetal nervous regulation, is regulated by intrapineal peptidergic pinealocytes via a synaptic mechanism. A possible paracrine role of the opioidergic cells must also be considered.     

Fine structure of the spermatozoon of the sea cucumber,Leptosynapta clarki (Echinodermata: Holothuroidea)

Summary The spermatozoon of the holothurian Leptosynapta clarki has a small circular head measuring about 3.0 at the greatest diameter, a midpiece containing a single mitochondrion and a tail flagellum measuring between 35 and 45 in length. The acrosomal region contains a granule measuring 0.7 in diameter which consists of electron dense material arranged in concentric lamellae. Five concentric very electron dense lamellae alternate with areas of much less electron dense material in the central region of the granule. This granule rests in an anterior nuclear depression.The nucleus is circular in shape and contains one or two unbound vacuoles which frequently contain a fine granular material. Posteriorly the nucleus is bounded by a large mitochondrion and an occasional Golgi complex. The proximal centriole which contains a lateral arm of dense material lies in a deep fossa projecting into the nucleus. The distal centriole lies posteriorly in the mitochondrial mass and gives rise to nine satellite projections and their Y-shaped connective extensions.The tail contains the 9 + 2 tubule arrangement and tapers at its distal end.This investigation was supported by a National Research Council grant to F. S. Chia.     

Soldier bug predation on swallowtail caterpillars (Lepidoptera: Papilionidae): Circumvention of defensive chemistry

All larvae in the family Papilionidae possess osmeteria, eversible glands that release defensive chemicals upon disturbance. These chemicals have been shown to be repellent to ants, mantids, and other predaceous arthropods with chewing mouthparts. In this study, we demonstrate that the pentatomid Podisus maculiventris,an important predator of the black swallowtail Papilio polyxenes,is capable of piercing the body wall of the caterpillar and consuming body fluids without eliciting osmeterial eversion. Tenebrio molitorlarvae coated with osmeterial secretions of Papilio polyxeneswere universally rejected by Podisus maculiventris,suggesting that the predator is in fact repelled by the swallowtail defensive chemistry. By circumventing the defensive behavior of the caterpillar, the pentatomid is able to utilize an otherwise chemically unsuitable prey species.     

Ultrastructure of the aortic diverticula of the adult dragonfly Sympetrum danae (Odonata: anisoptera)

Summary The aorta of Sympetrum danae possesses two dorsal diverticula: one in the mesothorax and one in the metathorax. They are very similar in form and position. Each diverticulum has a dorsal valve through which blood is pumped from the wings down into the aorta. The wall of the aortic diverticula consists of two simple cell layers: an outer epidermis-like layer and an inner muscle layer. The nuclei of the muscle cells are situated close to the lumen of the diverticula. The mitochondria are evenly dispersed between the myofibrils and are often paired up on either side of the Z-band. The Z-bands are thick and fragmented. The length of the sarcomeres varies from 3.3 to 6.1 . The A-band length is about 3 . The myofibrils consist of thick (250 Å) and thin (85 Å) filaments. Each thick filament is surrounded by 9–12 thin filaments. The sarcoplasmic reticulum is well developed and separates the myofibrils with one or two layers. The T-tubules are flattened and branch irregularly like a two-dimensional tree between the lamellar myofibrils. Intercalated discs are observed.The peculiarities of the muscle of aortic diverticula in S. danae are discussed in relation to various muscles of other insects and arthropods.