Digenetic trematodes of the genus Clinostomum Leidy, 1856 (Digenea : Clinostomidae) from birds of Queensland, Australia, including C. wilsoni n. sp. from Egretta intermedia

Two species of Clinostomum previously described from Australia, C. hornum from Botaurus poiciloptilus (Australian bittern) and Nycticorax caledonicus (Nankeen night heros) and C. australiense from Pelecanus conspicillatus (Australian pelican), which have previously been synonymised with C. complanatum, are redescribed and recognised as valid species. In addition, C. complanatum is recorded from Egretta alba (large egret), E. garzetta (little egret), E. intermedia (plumed egret), N. caledonicus and Ardea novaehollandiae (white-faced heron). C. wilsoni n. sp. is described from E. intermedia from Queensland. C. wilsoni differs from the other three species in size and shape of the body and in the oral collar, oral sucker, intestinal caeca, caecal diverticula and position of testes. Taxonomic problems within the genus Clinostomum are discussed.

Maternal care and infant behaviour of the bridled nailtail wallaby (Onychogalea fraenata)

Bridled nailtail wallabies Onychogalea fraenata are endangered, medium-sized, nocturnal macropodids that persist at only one location in central Queensland, Australia. Characteristics of juvenile development, shelter use, anti-predator behaviour and maternal care were investigated in the wild using trapping, radio-tracking and spotlighting observations., Timing of developmental stages was identical to the pattern previously found in captivity, except for age at weaning which was much earlier in the wild. After young had left the pouch permanently at 17 weeks of age and weighing c. 800 g, they always spent the day concealed in dense cover, generally > 200 m from their mothers. Juveniles were also alone in > 50% of observations at night, and stayed closer to cover than did adult females. Young became independent of their mothers 7-8 weeks after permanent exit from the pouch and weighing c. 1800 g. Females with dependent juveniles changed their behaviour in ways likely to reduce predation on young. They reduced their home ranges, stayed closer to cover and became more wary than other females. Juveniles differed from adult females in their habitat use, anti-predator behaviour and shelter site preferences. Juveniles were more likely than adults to respond to threats by standing still or lying flat on the ground, whether or not they were in concealing cover. Juveniles used a wider range of smaller shelters than adults, and were less likely to use solid shelters such as hollow logs during the day. Because bridled nailtail wallabies have a 'hider' strategy of maternal care and the young rely on crypsis, successful breeding in the wild requires dense vegetation cover.

Diurnal changes in the photochemical efficiency of the symbiotic dinoflagellates (Dinophyceae) of corals: photoprotection, photoinactivation and the relationship to coral bleaching

The photochemical efficiency of symbiotic dinoflagellates within the tissues of two reef-building corals in response to normal and excess irradiance at wafer temperatures < 30 C were investigated using pulse amplitude modulated (PAM) chlorophyll fluorescence techniques, Dark-adapted F-v/F-m showed clear diurnal changes, decreasing to a low at solar noon and increasing in the afternoon. However, F-v/F-m also drifted downwards at night or in prolonged darkness, and increased rapidly during the early morning twilight. This parameter also increased when the oxygen concentration of the wafer holding the corals was increased. Such changes have not been described previously, and most probably reflect state transition's associated with PQ pool reduction via chlororespiration. These unusual characteristics may be a feature of an endosymbiotic environment, reflective of the well-documented night-time tissue hypoxia that occurs in corals. F-v/F-m decreased to 0.25 in response to full sunlight in shade-acclimated (shade) colonies of Stylophora pistillata, which is considerably lower than in light-acclimated (sun) colonies. In sun colonies, the reversible decrease in F-v/F-m was caused by a lowering of F-m and F-o suggesting photoprotection and no lasting damage. The decrease in F-v/F-m, however, was caused by a decrease in F-m and an increase in F-o in shade colonies suggesting photoinactivation and long-term cumulative photoinhibition. Shade colonies rapidly lost their symbiotic algae (bleached) during exposure to full sunlight. This study is consistent with the hypothesis that excess light leads to chronic damage of symbiotic dinoflagellates and their eventual removal from reef-building corals. It is significant that this can occur with high light conditions alone.

Analysis of the wind field and heat budget in an alpine lake basin during summertime fair weather conditions

Observational data collected in the Lake Tekapo hydro catchment of the Southern Alps in New Zealand are used to analyse the wind and temperature fields in the alpine lake basin during summertime fair weather conditions. Measurements from surface stations, pilot balloon and tethersonde soundings, Doppler sodar and an instrumented light aircraft provide evidence of multi-scale interacting wind systems, ranging from microscale slope winds to mesoscale coast-to-basin flows. Thermal forcing of the winds occurred due to differential heating as a consequence of orography and heterogeneous surface features, which is quantified by heat budget and pressure field analysis. The daytime vertical temperature structure was characterised by distinct layering. Features of particular interest are the formation of thermal internal boundary layers due to the lake-land discontinuity and the development of elevated mixed layers. The latter were generated by advective heating from the basin and valley sidewalls by slope winds and by a superimposed valley wind blowing from the basin over Lake Tekapo and up the tributary Godley Valley. Daytime heating in the basin and its tributary valleys caused the development of a strong horizontal temperature gradient between the basin atmosphere and that over the surrounding landscape, and hence the development of a mesoscale heat low over the basin. After noon, air from outside the basin started flowing over mountain saddles into the basin causing cooling in the lowest layers, whereas at ridge top height the horizontal air temperature gradient between inside and outside the basin continued to increase. In the early evening, a more massive intrusion of cold air caused rapid cooling and a transition to a rather uniform slightly stable stratification up to about 2000 m agl. The onset time of this rapid cooling varied about 1-2 h between observation sites and was probably triggered by the decay of up-slope winds inside the basin, which previously countered the intrusion of air over the surrounding ridges. The intrusion of air from outside the basin continued until about mid-night, when a northerly mountain wind from the Godley Valley became dominant. The results illustrate the extreme complexity that can be caused by the operation of thermal forcing processes at a wide range of spatial scales.

Interactions among endocrinology, seasonal reproductive cycles and the nesting biology of the female green sea turtle

We collected data on plasma levels of testosterone+5a-dihydrotestosterone (T+DHT) and corticosterone (CORT) from adult female green sea turtles (Chelonia mydas) from southern Queensland during distinct stages of their reproductive cycle. Those females capable of breeding in a given year had elevated plasma steroid levels (T+DHT 0.91 +/- 0.08; CORT 1.05 +/- 0.29 ng/ml), associated with follicular development, until courtship began in October. At the beginning of the nesting season in November plasma levels of 2 CORT were related to when the female first nested (r(2) = 0.06; F = 10.45; P = 0.01). However, they were not correlated with the number of clutches a female laid in that season (F = 3.65; P = 0.08). We repeatedly sampled 23 turtles over the nesting season and profiled changes in steroids immediately following oviposition of each clutch. Levels of T+DHT (range 0.41-0.58 ng/ml) and CORT (range 2.13-2.81 ng/ml) were similar through the early stages of the nesting season and inter-nesting period, and declined to near basal levels (T+DHT 0.37 +/- 0.03 and CORT 1.85 +/- ng/ml) following the last clutch for the season. Steroid hormone levels were also low (T+DHT 0.38 +/- 0.16; CORT 0.46 +/- 0.21 ng/ml) in four independent post-breeding (atretic) females; samples for these females were taken at a time when body condition was presumably at the lowest for the season. Subtle changes in the nesting environment, such as variation in nesting habitat or the time of night that nesting occurred, were associated with a small and slow CORT increase. We suggest CORT is increased in nesting females to assist in lipid transfer to prepare the ovarian follicles and/or the reproductive organs for ovulation.

Emergence rates from the benthos of the parasitic juveniles of gnathiid isopods

Variation in the rate at which parasitic gnathiid isopod juveniles emerged from the benthos at Lizard Island, Great Barrier Reef, Australia, was examined (I) every 4 or 8 h throughout the day and night over a 24 h period, (2) over a 12 h period during the day or night, and (3) during different lunar phases (weeks). The number of gnathiids sampled per 4 or 8 h was low, with only 30% of the traps containing gnathiids and the abundance ranging from 0 to 3 gnathiids m(-2). The number of gnathiids that emerged over 12 h, in contrast, ranged from 0 to 36 m(-2). During the third and fifth weeks sampled, more gnathiids emerged during the day than at night. This coincided with the full moon and new moon. Most gnathiids that emerged from the reef during the day (98 %) had not fed, in contrast to those sampled at night (71%). Of the gnathiids with no engorged gut, most (97 %) of those collected during the day were small (II. mm) compared to those collected at night (19%), the latter being mostly >1 mm. Of the gnathiids with an engorged gut, most were sampled at night (83 %) and 97 % were >1 mm in size. These percentages suggest differences in the emergence behaviour among Life stages or species of gnathiids. This study, which shows that gnathiids do emerge during the day and supports other studies showing that gnathiids also attack fishes during the day, has important implications for understanding the role of cleaner fish and their main food source, gnathiids, as it shows there is a constant source of gnathiids emerging from the reef during the day and night in search of hosts.