Effects of temperature and predator:prey ratio on feeding rate in larvae of Atherix lantha Webb (Diptera: Athericidae)

1997 ◽  
Vol 75 (4) ◽  
pp. 644-647
Author(s):  
Fiona F. Hunter ◽  
Tami M. Sadonoja
Keyword(s):  
Feeding Rate ◽  
Temperature Regimes ◽  
Effects Of Temperature

Predator:prey experiments were conducted in the laboratory using snipe fly (Atherix lantha Webb) larvae as predators and hydropsychid caddisflies (Cheumatopsyche spp.) as prey. The effects on feeding rate of two different temperature regimes (20 and 10 °C) and five different predator:prey ratios (3:1, 2:1, 1:1, 1:2, 1:3) were tested. The number of caddisflies consumed per A. lantha larva per day was significantly greater at 20 °C than at 10 °C for the 2:1, 1:1, and 1:2 ratios (2×, 7×, and 2× greater, respectively). There were no significant differences between the 20 and 10 °C treatments at either the 3:1 or 1:3 ratio.

Effect of temperature, population density, and sex on feeding damage caused by adult pea leaf weevil (Coleoptera: Curculionidae)

2020 ◽  
pp. 1-10
Author(s):  
Vivian Morley-Senkler ◽  
Jonathon Williams ◽  
Meghan Vankosky
Keyword(s):  
Population Density ◽  
Feeding Rate ◽  
Abiotic Factors ◽  
Daily Temperature ◽  
Effect Of Temperature ◽  
Feeding Damage ◽  
Growing Seasons ◽  
Temperature Regimes ◽  
Important Pest ◽  
Effects Of Temperature

Abstract Sitona lineatus (Linnaeus) (Coleoptera: Curculionidae) is an important pest of Pisum sativum Linnaeus (Fabaceae) and Vicia faba Linnaeus (Fabaceae). Managing S. lineatus is difficult. There is currently no forecast that can be used to predict S. lineatus population densities between growing seasons (when management decisions are made). Sitona lineatus populations are monitored in spring by assessing adult-induced feeding damage. We assume the quantity of feeding damage is indicative of population density. However, the effects of abiotic factors, including temperature, on feeding rate are not known. We assessed the effects of temperature, population density, and sex on S. lineatus feeding rate by counting feeding notches on host plants exposed to adult weevils for 24 hours at four densities and under five temperature regimes. Individual females consumed more than male weevils. As expected, feeding damage increased with weevil density. The influence of temperature increased as weevil densities increased. Feeding rate did not differ between constant and fluctuating temperature regimes of equal mean daily temperature. Thus, a model based on mean daily temperature may predict weevil density if temperature and damage levels are known. Historical survey data for S. lineatus could be used to develop and validate new models.

scholarly journals Effects of temperature on the behaviour and metabolism of an intertidal foraminifera and consequences for benthic ecosystem functioning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noémie Deldicq ◽  
Dewi Langlet ◽  
Camille Delaeter ◽  
Grégory Beaugrand ◽  
Laurent Seuront ◽  
...  
Keyword(s):  
High Temperature ◽  
Ecosystem Functioning ◽  
Photosynthetic Activity ◽  
Species Traits ◽  
Biogeochemical Cycles ◽  
Variable Environment ◽  
Sediment Reworking ◽  
Temperature Regimes ◽  
Slow Moving ◽  
Effects Of Temperature

AbstractHeatwaves have increased in intensity, duration and frequency over the last decades due to climate change. Intertidal species, living in a highly variable environment, are likely to be exposed to such heatwaves since they can be emerged for more than 6 h during a tidal cycle. Little is known, however, on how temperature affects species traits (e.g. locomotion and behaviour) of slow-moving organisms such as benthic foraminifera (single-celled protists), which abound in marine sediments. Here, we examine how temperature influences motion-behaviour and metabolic traits of the dominant temperate foraminifera Haynesina germanica by exposing individuals to usual (6, 12, 18, 24, 30 °C) and extreme (high; i.e. 32, 34, 36 °C) temperature regimes. Our results show that individuals reduced their activity by up to 80% under high temperature regimes whereas they remained active under the temperatures they usually experience in the field. When exposed to a hyper-thermic stress (i.e. 36 °C), all individuals remained burrowed and the photosynthetic activity of their sequestered chloroplasts significantly decreased. Recovery experiments subsequently revealed that individuals initially exposed to a high thermal regime partially recovered when the hyper-thermic stress ceased. H. germanica contribution to surface sediment reworking substantially diminished from 10 mm3 indiv−1 day−1 (usual temperature) to 0 mm3 indiv−1 day−1 when individuals were exposed to high temperature regimes (i.e. above 32 °C). Given their role in sediment reworking and organic matter remineralisation, our results suggest that heatwaves may have profound long-lasting effects on the functioning of intertidal muddy ecosystems and some key biogeochemical cycles.

Effects of Temperature on Leaf Expansion in Sunflower

1982 ◽  
Vol 9 (2) ◽  
pp. 209 ◽  
Author(s):  
HM Rawson ◽  
JH Hindmarsh
Keyword(s):  
Field Studies ◽  
Leaf Expansion ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Leaf Position ◽  
Leaf Emergence ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Relative Change

Five commercial cultivars of sunflower were grown in cabinets at three temperature regimes, 32/22, 27/17 and 22/12°C, and with 15-h and 11-h photoperiods, and expansion of leaves 5-15 was followed. Leaves appeared faster with increasing temperature (0.022 leaves day-1 °C-1) and with increasing daylength. Areas of individual leaves increased linearly up the plant profile and, although final area per leaf (Amax) decreased with increasing temperature, the relative change was similar for each leaf position. Cultivars maintained their ranking for Amax across temperatures, and these rankings agreed with those in previous field studies. Within each temperature regime, both the expansion rate of leaves and the duration of expansion increased with leaf position. As temperature increased, leaves grew for shorter periods with a change of 1.04 days °C-1, but under the photon flux density used (500 �mol m-2 s-1, or about 25% full sunlight) expansion rates were greatest at the lowest temperature. Expansion rates were only one-third of those in field studies at comparable temperatures, but durations were similar. Cultivars that achieved the largest Amax did so via faster rates of expansion and not via longer durations: only one cultivar differed from the mean (20 days) duration of leaf expansion. All cultivars reached floral initiation progressively earlier with extension of photoperiod from 10 to 15 h, with the change for the most sensitive cultivars being 8 days and for the least sensitive 5 days. Rates of leaf emergence were linked with this sensitivity.

RESPONSE OF PEAS TO ENVIRONMENT: II. EFFECTS OF TEMPERATURE IN CONTROLLED-ENVIRONMENT CABINETS

1966 ◽  
Vol 46 (2) ◽  
pp. 195-203 ◽  
Author(s):  
B. Stanfield ◽  
D. P. Ormrod ◽  
H. F. Fletcher
Keyword(s):  
Plant Development ◽  
Dry Matter ◽  
Accumulation Rate ◽  
Stem Elongation ◽  
Controlled Environment ◽  
Dry Matter Accumulation ◽  
Average Temperature ◽  
Pisum Sativum L ◽  
Temperature Regimes ◽  
Effects Of Temperature

Effects of day/night temperature regimes from 7/4 to 32/24 °C on growth and development of Pisum sativum L. var. Dark Skin Perfection were studied in controlled-environment cabinets. Light intensity was about 1500 foot-candles and the photoperiod was 16 hours. Rate of plant development, in terms of nodes produced per day, increased steadily as the average temperature increased. Rate of stem elongation, however, was most rapid at 21/13 °C; and plant height was greatest at 16/10 °C. On a dry matter accumulation rate basis, vine growth decreased above and below a temperature optimum which shifted from 21/16 to 16/10 °C in the course of plant development. The combination of high day and high night temperatures caused an increase in the number of nodes to the first flower. Tillering was most prolific at the lower temperatures and was absent at 32 °C day temperatures. Pea yield decreased as temperature increased above 16/10 °C, due mainly to a reduction in the number of pods per plant.

scholarly journals Effect of Environmental Factors on Seed Germination and Early Seedling Emergence of Carolina geranium (Geranium carolinianum)

2018 ◽  
Vol 36 ◽  
Author(s):  
X. LIU ◽  
T. ZONG ◽  
Y. LI ◽  
X. ZHOU ◽  
L. BAI
Keyword(s):  
Control Strategies ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Burial Depth ◽  
Invasive Weed ◽  
Temperature Regimes ◽  
Dark Regime ◽  
Early Seedling ◽  
Effects Of Temperature ◽  
And Control

ABSTRACT: Carolina geranium (Geranium carolinianum) is an emerging invasive weed in rape and wheat fields in China. A better understanding of its germination and emergence ecology will enable the development of integrated weed control strategies. In this study, we investigated the effects of temperature, photoperiod, soil water content, salinity, and burial depth, on germination and emergence of Carolina geranium. Germination percentages were over 74% under 15/20 and 20/25 oC night/day temperature regimes. Germination rate was independent of light/dark regime. Increasing salinity reduced germination of Carolina geranium from 81.1% at 0 mM to 0% at 160 mM NaCl. Seeds germination was peaked at 50% soil moisture, but was completely inhibited at < 20% and > 90%. The seedling emergence above 82.2% was observed when seeds were placed at a depth from 0 to 1 cm, and no seedlings emerged from seeds placed at a depth of 7 cm. Current work provide the basic information to effectively prevent and control this invasive weed in Chinese rape and wheat fields.

Inter- and intra-varietal variation in aerobic methane emissions from environmentally stressed pea plants

Botany ◽  
2018 ◽  
Vol 96 (12) ◽  
pp. 837-850 ◽  
Author(s):  
Awatif M. Abdulmajeed ◽  
Mohammad I. Abo Gamar ◽  
Mirwais M. Qaderi
Keyword(s):  
Stress Factors ◽  
Interactive Effects ◽  
Controlled Environment ◽  
Uvb Radiation ◽  
Pisum Sativum L ◽  
Temperature Regimes ◽  
Varietal Variation ◽  
Growth Chambers ◽  
Effects Of Temperature ◽  
Two Temperature

Environmental stress factors can influence methane (CH4) emissions from plants. There are a few studies on the interactive effects of stress factors on plant aerobic CH4, but none on the comparative evaluation of CH4 emissions between and among plant varieties. We examined the effects of temperature, UVB radiation, and watering regime on CH4 emissions from 10 pea (Pisum sativum L.) varieties first and then selected two varieties with the highest (237J Sundance; var. 1) and lowest (422 Ho Lan Dow; var. 2) emissions for further studies. Plants were grown in controlled-environment growth chambers under two temperature regimes (22 °C / 18 °C and 28 °C / 24 °C, 16 h light / 8 h dark), two UVB levels (0 and 5 kJ·m−2·d−1), and two watering regimes (well-watered and water-stressed) for 14 days, after one week of growth under 22 °C / 18 °C. Higher temperatures and water stress increased CH4 emissions, and increased emission was associated with stress. Pea varieties varied in growth and CH4 emissions; var. 1 was more stressed and had higher emission than var. 2. In the stressed variety, the water-stressed plants grown under higher temperatures at UVB5 had the highest CH4 emission, whereas the well-watered plants grown under lower temperatures at UVB5 had the lowest emission. We conclude that climatic stress conditions increase CH4 emissions, which vary with plant varieties.

Some factors affecting the development and biocontrol of cotton seedling disease

1995 ◽  
Vol 35 (6) ◽  
pp. 771 ◽  
Author(s):  
HJ Ogle ◽  
AM Stirling ◽  
PJ Dart
Keyword(s):  
Pythium Ultimum ◽  
Disease Development ◽  
Symptom Development ◽  
Night Temperature ◽  
Factors Affecting ◽  
Seedling Disease ◽  
Susceptibility To Infection ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Number Of Seeds

The effects of temperature and cultivar on disease development in cotton were investigated in addition to the duration of susceptibility to infection and the timing of infection by Pythium ultimum and Rhizoctonia solani. Symptom development was also monitored. Disease was more severe at day/night temperature regimes of 20/15, 25/20, and 30/25�C than at 35/30�C. Disease development differed significantly between cotton cvv. Deltapine 90 and Siokra 1-4 at 30/25�C and 35/30�C. In glasshouse trials in field soil, both R. solani and P ultimum were isolated from seeds as early as 2 h after inoculation, although most seeds were not infected with P. ultimum until 10 h after inoculation and with R. solani until 24 h after inoculation. Increasing the duration of exposure to inoculum increased the number of seeds infected and reduced the number of plants surviving. Seedlings were resistant to P. ultimum infection by 14 days after sowing but were not resistant to infection by R. solani until 28 days after sowing.

Effects of temperature on development and progression in rape of crown canker caused by Leptosphaeria maculans

1975 ◽  
Vol 15 (76) ◽  
pp. 705 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Brassica Napus ◽  
Temperature Regime ◽  
Leptosphaeria Maculans ◽  
Stem Infection ◽  
Temperature Regimes ◽  
Germination Temperature ◽  
Effects Of Temperature ◽  
Canker Development ◽  
Rape Seedlings

Aspects of the development and progression of blackleg crown canker in rape seedlings (Brassica napus and B. campestris), following stem infection by L. maculans ascospores were examined at three temperature regimes; 12/7�C, 18/11�C, and 24/15�C. Crown cankers were produced at all temperatures on seedlings inoculated one week after germination. Temperature regime was shown to be a major factor determining the time of first appearance of crown cankers after inoculation; 12/7�C being the least favourable for crown canker development of the three regimes used. Temperature regime had a significant effect upon the time taken for infected plants to die, the 12/7�C regime being the optimum for slowest plant death, Infected B. napus plants died at a faster rate than B. campestris. Temperature regime was also shown to influence the nature, or type, of crown canker that developed.

Variation of Seed Dormancy and Germination Ecology of Cowcockle (Vaccaria hispanica)

Weed Science ◽  
2014 ◽  
Vol 62 (3) ◽  
pp. 483-492 ◽  
Author(s):  
Hema S. N. Duddu ◽  
Steven J. Shirtliffe
Keyword(s):  
Seed Dormancy ◽  
Great Plains ◽  
Northern Great Plains ◽  
Light Conditions ◽  
Primary Dormancy ◽  
Local Environments ◽  
Temperature Regimes ◽  
Effects Of Temperature ◽  
Two Temperature ◽  
Seed Dormancy And Germination

Cowcockle, an introduced summer annual weed of the Northern Great Plains, is being considered for domestication because of its high quality starch, cyclopeptides, and saponins. Loss of seed dormancy is one of the key desirable traits for domestication. To determine the potential for domestication of this species, an understanding of the seed dormancy and germination patterns is required. The objectives of this study were to evaluate seed dormancy in cowcockle ecotypes and determine how temperature and light affect seed dormancy. We evaluated 15 populations of cowcockle for primary dormancy by exposing them to five temperatures (5, 7.5, 10, 15, and 20 C) under two temperature regimes (constant and alternating) in both dark and light conditions. Freshly matured seeds of all the populations showed high levels of primary dormancy except ‘Mongolia’. Lower levels of dormancy at medium temperatures (10 and 15 C) and greater dormancy at low and high temperatures suggest conditional dormancy, a state at which seeds germinate over a narrower range of conditions compared to nondormant seeds. The effects of temperature regime, light, and their interaction was significant only at suboptimal (5 and 7.5 C) and supraoptimal (20 C) temperatures. Under these conditions, alternating temperatures were more effective in breaking the conditional dormancy, followed by light. The variation in optimum temperature, light, and their interactions among the cowcockle populations may be due to the plants evolving to adapt to their local environments. From a domestication perspective, the conditional dormancy in cowcockle can be observed as an evolutionary mechanism that prevents untimely germination following maturity and may not be a major obstacle for its domestication.

Sign in / Sign up

Export Citation Format

Share Document