The effects of the anaesthetic quinaldine on oxygen consumption in an intertidal teleost Blennius pholis (L.)

The effects of the anaesthetic quinaldine on oxygen consumption in an intertidal teleost Blennius pholis (L.) were investigated. Oxygen consumption generally decreases with increasing quinaldine concentration in environmental water. However, at low concentrations, oxygen consumption of smaller specimens is slightly increased. Generally, smaller specimens have their oxygen consumption affected less by a given quinaldine concentration than do larger specimens, as the former appear to be at less depressed stages of anaesthesia. This is thought to be due to smaller B. pholis becoming saturated with quinaldine more rapidly but simultaneously being afforded more rapid removal, because of their greater relative gill area per unit body volume. The reduction of oxygen consumption at high concentrations of quinaldine is great.     

Oxygen consumption by sticklebacks (Gasterosteus aculeatus L.) exposed to zinc

The rate of oxygen consumption by sticklebacks has been studied by long-term continuous-flow respirometry. Exposure to 1 p.p.m. zinc in calcium-free water causes wide variations in individual responses, but oxygen uptake tends to rise and then become extremely erratic, before declining as death approaches. Behavioural abnormalities such as increased ventilation rate, loss of balance, and long periods of inactivity alternating with spasmodic swimming also occur. Exposure to 6.5 p.p.m. zinc in high-calcium water generally causes a rise in oxygen consumption, followed by fluctuations in the rate of uptake, but no behavioural abnormalities occur and deaths are rare even after exposure for 400 h. If restored to zinc-free water after 40 h exposure to zinc, recovery is generally complete, although fluctuating rates of oxygen uptake persist. These results are discussed in relation to previous work on the effects of heavy metals on fish respiration.     

Rates of oxygen consumption by Thais (Nucella) Lapillus (L.)

Oxygen consumption by Thais varied seasonally with higher values in summer than in winter. This seasonal difference was due in part to the effects of temperature and in part to those of feeding. During feeding, rates of oxygen consumption were high, but declined in the period between meals. There was little evidence of acclimation of oxygen consumption to changes in temperature; low (winter) rates of consumption were more sensitive to increases in temperature than were high (summer) rates. A polynomial expression, including terms for temperature and ‘time since last meal’, was derived for the constant a′ in the allometric equation relating oxygen consumption (_o2) to dry body weight: _o2 = a′.W^0.511.     

Diet of Lipophrys pholis (L.) (Teleostei,Blenniidae) in Cantabrian coastal waters (Spain)

Between February and December 1988, a total of 261 specimens of Lipophrys pholis were caught in eleven intertidal pools on the western coast of Asturias. This blenniid species mainly feeds on different groups of invertebrates, although algal remains also appear. Mollusca is the most highly represented taxon with the largest number of prey being Gastropoda, followed by Bivalvia and, to a lesser degree, Polyplacophora. Crustacea is well represented by Cirripedia. Isopoda also stands out and Amphipoda, Tanaidacea and Decapoda appear sporadically. Temporal diet analysis throughout the year shows no great differences. Likewise, a great similarity was observed among the feeding of L. pholis specimens collected in pools at a different tidal level, of variable size and with different algal cover. Changes in diet are appreciable as size increases, especially from a length of 6 cm on.     

Host feeding responses of Aedes aegypti (L.) exposed to deltamethrin

Escape responses of mated and unmated nulliparous Aedes aegypti mosquitoes were compared using three different concentrations of deltamethrin in the presence or absence of a live animal host using an excito-repellency (ER) test system. Both insecticide contact (excitation) and non-contact (repellency) test configurations were compared. For contact trials, mated mosquitoes showed similar escape movements among the three concentrations when host stimuli were absent. Significant differences in responses were seen between the lower concentrations of (LC(50) and LC(75) ) deltamethrin with and without hosts present (P<0.05). Presence or absence of host stimuli produced no significant differences in escape response for unmated females when exposed to the highest concentration (LC(90) ) of deltamethrin. Our findings indicate that as deltamethrin concentrations decrease to sublethal levels, mating status and host cues play a more significant role in escape behavior. Therefore, insemination can influence the outcome of feeding success and flight movement of nulliparous female Ae. aegypti in contact with deltamethrin and in the presence of live host stimuli. The ER assay system serves as a useful tool for observing excitation and repellency responses of Ae. aegypti to insecticides in the presence or absence of other environmental and biological cues that can affect mosquito behavior.     

Changes in cardiac activity, oxygen uptake and perfusion indices in Carcinus maenas (L.) exposed to crude oil and dispersant

Cardiac activity and oxygen consumption increased when C. maenas were exposed to a 20% solution of the water-soluble fraction of Fortes crude oil, a 10% solution of the dispersant BP1100WD or a combination of both. Normal feeding behaviour was disrupted. Perfusion indices (Q/VO2) decreased as locomotor activity increased following exposure to crude oil. However, exposure to dispersant or dispersant + crude oil resulted in elevation of perfusion index despite crabs becoming active. All test animals survived for at least 6 weeks following exposure to the pollutants. The acute, sublethal effects of dispersant and dispersant + crude oil were more severe than the effects of crude oil alone.     

Agonistic behaviour and control of access to hiding places in two intertidal blennies, Lipophrys pholis and Coryphoblennius galerita (Pisces: Blenniidae)

In this study we investigated the relationships between dominance rank and access to shelters in captive groups of Lipophrys pholis and Coryphoblennius galerita, as well as the effects of group size and shelter availability. Dominance rank was strongly correlated with size in juvenile L. pholis and with sex and size in adult C. galerita, males being dominant over females of similar size. Access to shelters was significantly correlated with dominance rank. For both species, most interactions occurred out of shelters. Direct disputes over shelters were always initiated by the dominant fish and the initiator was always the winner. The rate of aggression per fish per unit time decreased with an increase in the number of fish in L. pholis but not in C. galerita. No significant differences were found in groups differing in the number of shelters. C. galerita showed a higher rate of agonistic interactions and a higher proportion of overt aggression than L. pholis. It is suggested that one of the functions of agonistic interactions in these fishes is the control of a set of shelters, in the network of pathways used by each individual within its home range, minimising the time required to hide in case of danger. Received in revised form: 29 January 2001 Electronic Publication     

The responses of bonobos (Pan paniscus) to their mirror images: Evidence of selfrecognition

This research examined the responses of bonobos (Pan paniscus) to their mirror images. Nine bonobos were presented alternately with the reflective and non-reflective sides of a mirror. The apes exhibited considerable interest in the mirror, and immature animals exhibited higher frequencies of contingent action and inactive looking than did adults. four animals used the mirror to inspect parts of their bodies that were otherwise not visible to them, indicating that bonobos are capable of self-recognition.     

Increased sensitivity to mirror symmetry in autism

Can autistic people see the forest for the trees? Ongoing uncertainty about the integrity and role of global processing in autism gives special importance to the question of how autistic individuals group local stimulus attributes into meaningful spatial patterns. We investigated visual grouping in autism by measuring sensitivity to mirror symmetry, a highly-salient perceptual image attribute preceding object recognition. Autistic and non-autistic individuals were asked to detect mirror symmetry oriented along vertical, oblique, and horizontal axes. Both groups performed best when the axis was vertical, but across all randomly-presented axis orientations, autistics were significantly more sensitive to symmetry than non-autistics. We suggest that under some circumstances, autistic individuals can take advantage of parallel access to local and global information. In other words, autistics may sometimes see the forest and the trees, and may therefore extract from noisy environments genuine regularities which elude non-autistic observers.     

Respiratory potential of maize (Zea mays L.) roots exposed to hypoxia

When hypoxia is not too severe, root aerobic metabolism can be partly supported by oxygen delivery via aerenchymateous tissues. In terms of supplying energy, this adaptation is of special importance in plants with a high metabolic demand, such as maize (Zea mays L.). The ability of maize to respond to hypoxia by morphological changes is well documented; however, little is known on the potential for oxidative metabolism in different types of maize roots. In our study, we assessed the root respiratory potential in seminal and adventious nodal roots of maize exposed to mild short-term hypoxia. Plants responded to the treatment with an increased portion of nodal roots per total root length, while there were no changes in the biomass of shoots and roots. Thick nodal roots had much higher respiratory potential (Electron Transport System Activity – ETS) than nodal roots of smaller diameter or seminal roots, irrespective of the aeration rate. The only change in ETS under oxygen deficiency was found for seminal roots where oxygen consumption increased by 25%. Increased root porosity was observed in all roots, the increase was higher in nodal roots. On the basis of ETS data and taking into account changes of root morphology, it can be concluded that large changes of root respiratory potential are not involved in the response of maize to hypoxia. Obviously, maize can cover the respiratory needs with shifts in the growth of different root types which inherently differ in their potential aerobic respiration.     

Ichthyophthiriasis in the mirror carp Cyprinus carpio (L.) III. Pathology

The microscopical pathology of Ichthyophthiriasis was studied in a group of mirror carp infected with measured numbers of parasites under standardized conditions. Primary pathology consisted of inflammatory, proliferative, and degenerative changes in the epidermis and hyperaemia and oedema of the spongiose dermis. This was accompanied by changes in the amount and distribution of pigment in the spongiose dermis. Proliferation of interlamellar epithelial tissue of the gills in response to the parasite resulted in partial or complete filling of the interlamellar spaces. Secondary changes noted in the disease were devacuolization of hepatocytes, leukocytic depletion of the mesonephric kidneys, and leukocytic metaplasia or hyperplasia in the spleen.