An experimental study of the pattern and significance of the climbing behaviour of Hydrobia ulvae

1981 ◽  
Vol 61 (2) ◽  
pp. 285-299 ◽  
Author(s):  
R. S. K. Barnes
Keyword(s):  
Population Density ◽  
Laboratory Experiments ◽  
Field Experiments ◽  
High Tide ◽  
Field Observations ◽  
Laboratory Studies ◽  
Hydrobia Ulvae ◽  
Tidal Water ◽  
Climbing Behaviour ◽  
Incoming Tide

The climbing behaviour of the gastropod Hydrobia ulvae (Pennant) and its relationship with flotation/dispersal were investigated by field observations and experiments in Norfolk, U.K. and by laboratory experiments. Field experiments of the type used by previous authors were discontinued when it was observed that counts at low tide of snails which had climbed objects the previous high tide did not reflect adequately climbing activity during that period of tidal cover. Both field and laboratory studies yielded five general results: (i) snails climbed only when covered by tidal water; (ii) climbing activity was not related to population density; (iii) climbing activity, under conditions of constant population density, varied markedly during the cycle of spring tidal cover, reaching a peak after the first few tides and declining rapidly thereafter; (iv) maximum numbers of snails were present on submerged structures relatively early in any given period of cover and declined (snails crawled downwards off the structure) as the period of cover continued; and (v) rarely were large proportions of climbed Hydrobia floated off their support by the incoming tide; this was associated only with conditions of extreme calm.

Ecology and behaviour of immature Culicoides melleus (Coq.) (Dipt., Ceratopogonidae)

1972 ◽  
Vol 62 (1) ◽  
pp. 113-127 ◽  
Author(s):  
J. R. Linley ◽  
G. M. Adams
Keyword(s):  
Intertidal Zone ◽  
Laboratory Experiments ◽  
High Tide ◽  
Time Of Day ◽  
Fourth Instar ◽  
Tidal Level ◽  
Sand Surface ◽  
Tide Level ◽  
The Vertical Distribution ◽  
Incoming Tide

The distribution of the larvae and pupae of Culicoides melleus (Coq.) in a natural beach habitat in an inlet on the Florida coast was studied in relation to tidal level and time of day. Larvae and pupae were confined to the intertidal zone and these distributions were unaffected by time of day or tidal level. Distributions of younger larval instars were displaced towards the inferred area of oviposition at higher elevations on the beach. Pupae were associated with the zone at and somewhat below high tide level. Differences in the vertical distribution of larvae between 0 and 2 in. deep between dark (pre-dawn)/low tide, morning/low tide and afternoon/low tide conditions were probably associated with larval response to light and heat.In laboratory experiments with a temperature gradient, second- to fourth-instar larvae preferred the 18–25°C range, but the fourth instars were the least discriminating. Laboratory experiments with a simulated beach showed that pupae flooded on an incoming tide remained in their burrows and immediately buried themselves more deeply when waves were generated in the water; they were able to return to the surface if buried, and survived drowning for four days. Inundated areas were avoided as pupation sites. The orientation of pupae at the sand surface and their formation in burrows was related to negative phototactic responses of the pupating larvae.

scholarly journals Oxidation of atmospheric reduced sulphur compounds: perspective from laboratory studies

1997 ◽  
Vol 352 (1350) ◽  
pp. 171-182 ◽  
Author(s):  
A. R. Ravishankara ◽  
Yinon Rudich ◽  
Ranajit Talukdar ◽  
Stephen B. Barone
Keyword(s):  
Boundary Layer ◽  
Laboratory Experiments ◽  
Marine Boundary Layer ◽  
Field Observations ◽  
Dimethyl Sulphide ◽  
Laboratory Studies ◽  
Sulphur Compounds ◽  
Complex Sequence ◽  
End Products ◽  
Reduced Sulphur Compounds

Results of laboratory experiments which address the course of the OH + DMS (dimethyl sulphide) reaction in the atmosphere are presented. It is shown that OH reacts via a complex sequence of reactions to produce CH 3 S and other products, and argued that NO 3 is unlikely to be an important oxidizer of DMS in the marine boundary layer (MBL) because it is very efficiently taken up by water droplets. A simplified mechanism for the oxidation of DMS in the troposphere is presented. This mechanism explains some of the field observations on the end products of DMS oxidation and their variations with temperature.

Field and laboratory studies on sexual attractiveness of females of Prays citri (Mill.) (Lep., Yponomeutidae)

1974 ◽  
Vol 63 (3) ◽  
pp. 473-481 ◽  
Author(s):  
M. Sternlicht
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Sexual Attractiveness ◽  
Laboratory Studies ◽  
Sticky Traps ◽  
Adult Females ◽  
Prays Citri ◽  
Old Females

AbstractIn laboratory experiments with Prays citri (Mill.) in Israel, females 1–16 h old proved more attractive to 2–6-day-old males than did female pupae 1–8 h before emergence or female adults 1–4-days old. Attractiveness in the field was tested by means of sticky traps baited with female pupae or adult females. Females were attractive for up to 14 days in summer (19–30°C) and 27 days in winter (8–20°C). Greatest attraction was shown by 1–7-day-old females during summer as compared with 5–9-day-old females during winter. Field experiments with baited sticky traps attached to wind vanes showed that more males were caught by traps aligned with the wind than by those placed at right-angles to it or hung among tree branches, by traps 1–7 m above ground than those 30–50 cm above, and by traps five metres distant from trees than those 10–80 m distant.

Concentration of Impurities during Melting of Snow Made from Secondary Sewage Effluent

1986 ◽  
Vol 18 (2) ◽  
pp. 151-156 ◽  
Author(s):  
R. Zapf-Gilje ◽  
S. O. Russell ◽  
D. S. Mavinic
Keyword(s):  
Potassium Chloride ◽  
Chloride Solution ◽  
Laboratory Experiments ◽  
Field Experiments ◽  
Low Cost ◽  
Sewage Effluent ◽  
Potassium Chloride Solution ◽  
Laboratory Results ◽  
Solution Field ◽  
Concentration Of Impurities

When snow is made from sewage effluent, the impurities become concentrated in the early melt leaving the later runoff relatively pure. This could provide a low cost method of separating nutrients from secondary sewage effluent. Laboratory experiments showed that the degree of concentration was largely independent of the number of melt freeze cycles or initial concentration of impurity in the snow. The first 20% of melt removed with it 65% of the phosphorus and 90% of the nitrogen from snow made from sewage effluent; and over 90% of potassium chloride from snow made from potassium chloride solution. Field experiments with a salt solution confirmed the laboratory results.

scholarly journals Hydraulic transmissivity inferred from ice-sheet relaxation following Greenland supraglacial lake drainages

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ching-Yao Lai ◽  
Laura A. Stevens ◽  
Danielle L. Chase ◽  
Timothy T. Creyts ◽  
Mark D. Behn ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Ice Sheet ◽  
Drainage System ◽  
Greenland Ice Sheet ◽  
Field Observations ◽  
Surface Uplift ◽  
Drainage Networks ◽  
Order Of Magnitude ◽  
Lake Drainage ◽  
Magnitude Increase

AbstractSurface meltwater reaching the base of the Greenland Ice Sheet transits through drainage networks, modulating the flow of the ice sheet. Dye and gas-tracing studies conducted in the western margin sector of the ice sheet have directly observed drainage efficiency to evolve seasonally along the drainage pathway. However, the local evolution of drainage systems further inland, where ice thicknesses exceed 1000 m, remains largely unknown. Here, we infer drainage system transmissivity based on surface uplift relaxation following rapid lake drainage events. Combining field observations of five lake drainage events with a mathematical model and laboratory experiments, we show that the surface uplift decreases exponentially with time, as the water in the blister formed beneath the drained lake permeates through the subglacial drainage system. This deflation obeys a universal relaxation law with a timescale that reveals hydraulic transmissivity and indicates a two-order-of-magnitude increase in subglacial transmissivity (from 0.8 ± 0.3 $${\rm{m}}{{\rm{m}}}^{3}$$ m m 3 to 215 ± 90.2 $${\rm{m}}{{\rm{m}}}^{3}$$ m m 3 ) as the melt season progresses, suggesting significant changes in basal hydrology beneath the lakes driven by seasonal meltwater input.

scholarly journals Interactions Between Chill-Hours and Degree-Days Affect Carpogenic Germination in Monilinia vaccinii-corymbosi

2001 ◽  
Vol 91 (1) ◽  
pp. 77-83 ◽  
Author(s):  
H. Scherm ◽  
A. T. Savelle ◽  
P. L. Pusey
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Degree Days ◽  
Carpogenic Germination ◽  
Conditioning Period ◽  
Low Degree ◽  
Heating Degree Days ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship

The relationship of cumulative chill-hours (hours with a mean temperature <7.2°C) and heating degree-days (base 7.2°C) to carpogenic germination of pseudosclerotia of Monilinia vaccinii-corymbosi, which causes mummy berry disease of blueberry, was investigated. In two laboratory experiments, pseudosclerotia collected from rabbiteye blueberry in Georgia were conditioned at 5 to 6°C for 26 to 1,378 h prior to placement in conditions favorable for germination and apothecium development. The number of chill-hours accumulated during the conditioning period affected the subsequent proportion of pseudosclerotia that germinated and produced apothecia, with the greatest incidence of carpogenic germination occurring after intermediate levels of chilling (≈700 chill-hours). The minimum chilling requirement for germination and apothecium production was considerably lower than that reported previously for pseudo-sclerotia from highbush blueberry in northern production regions. The rate of carpogenic germination was strongly affected by interactions between the accumulation of chill-hours and degree-days during the conditioning and germination periods; pseudosclerotia exposed to prolonged chilling periods, once transferred to suitable conditions, germinated and produced apothecia more rapidly (after fewer degree-days had accumulated) than those exposed to shorter chilling periods. Thus, pseudosclerotia of M. vaccinii-corymbosi are adapted to germinate carpogenically following cold winters (high chill-hours, low degree-days) as well as warm winters (low chill-hours, high degree-days). Results were validated in a combined field-laboratory experiment in which pseudosclerotia that had received various levels of natural chilling were allowed to germinate in controlled conditions in the laboratory, and in two field experiments in which pseudosclerotia were exposed to natural chilling and germination conditions. A simple model describing the timing of apothecium emergence in relation to cumulative chill-hours and degree-days was developed based on the experiments. The model should be useful for better timing of field scouting programs for apothecia to aid in management of primary infection by M. vaccinii-corymbosi.

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