Parasites and low temperatures

Parasitology ◽  
1999 ◽  
Vol 119 (S1) ◽  
pp. S7-S17 ◽  
Author(s):  
D. A. Wharton
Keyword(s):  
Life Cycle ◽  
Cold Tolerance ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Free Living ◽  
Rate Of Growth ◽  
Subzero Temperatures ◽  
Growth Development ◽  
Epidemiological Significance

SUMMARYLow temperatures affect the rate of growth, development and metabolism of parasites and when temperatures fall below 0°C may expose the parasite to the potentially lethal risk of freezing. Some parasites have mechanisms, such as diapause, which synchronise their life cycle with favourable seasons and the availability of hosts. Parasites of endothermic hosts are protected from low temperatures by the thermoregulatory abilities of their host. Free-living and off-host stages, however, may be exposed to subzero temperatures and both freezing-tolerant and freeze-avoiding strategies of cold hardiness are found. Parasites of ectothermic hosts may be exposed to subzero temperatures within their hosts. They can rely on the cold tolerance adaptations of their host or they may develop their own mechanisms. Exposure to low temperatures may occur within the carcass of the host and this may be of epidemiological significance if the parasite can be transmitted via the consumption of the carcass.

REDUCED COLD-HARDINESS OF PEAR PSYLLA (HOMOPTERA: PSYLLIDAE) CAUSED BY EXPOSURE TO EXTERNAL WATER AND SURFACTANTS

1996 ◽  
Vol 128 (5) ◽  
pp. 825-830 ◽  
Author(s):  
David R. Horton ◽  
Tamera M. Lewis ◽  
Lisa G. Neven
Keyword(s):  
Low Temperatures ◽  
Cold Hardiness ◽  
Dilute Solutions ◽  
Subzero Temperatures ◽  
Pear Psylla ◽  
External Water

AbstractOverwintering pear psylla, Cacopsylla pyricola (Foerster), were misted with water or with one of several dilute solutions of water and surfactant, and then exposed to a range of subzero temperatures for 24 h. Misted psylla had significantly greater mortality than unmisted controls. Increases in mortality occurred at temperatures as warm as −6°C, a temperature well within the range of conditions in the field. At extreme low temperatures (−18°C) there was virtually no mortality in the unmisted controls, whereas mortality approached or reached 100% in several of the misted groups. Temperatures necessary to kill 50% of insects estimated for topically treated psylla ranged between −2.6 and −12.7°C for surfactant-treated insects, and below −18°C for water-treated or control insects. The possibility of using surfactants and water for control of overwintering pear psylla is discussed.

scholarly journals Autumn larval cold tolerance does not predict the northern range limit of a widespread butterfly species

2020 ◽  
Author(s):  
Philippe Tremblay ◽  
Heath A. MacMillan ◽  
Heather M. Kharouba
Keyword(s):  
Climate Change ◽  
Cold Tolerance ◽  
Species Distribution ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Species Distribution Models ◽  
Environmental Data ◽  
Range Shifts ◽  
Butterfly Species ◽  
Distribution Models

AbstractClimate change is driving range shifts, and a lack of cold tolerance is hypothesized to constrain insect range expansion at poleward latitudes. However, few, if any, studies have tested this hypothesis during autumn when organisms are subjected to sporadic low temperature exposure but may not have become cold tolerant yet. In this study, we integrated organismal thermal tolerance measures into species distribution models for larvae of the Giant Swallowtail butterfly, Papilio cresphontes, living at the northern edge of its actively expanding range. Cold hardiness of field-collected larvae was determined using three common metrics of cold-induced physiological thresholds: the supercooling point (SCP), critical thermal minimum (CTmin), and survival following cold exposure. P. cresphontes larvae in autumn have a CTmin of 2.14°C, and were determined to be tolerant of chilling. These larvae have a SCP of −6.6°C and can survive prolonged exposure to −2°C. They generally die, however, at temperatures below their SCP (−8°C), suggesting they are chill tolerant or modestly freeze avoidant. Using this information, we examined the importance of low temperatures at a broad scale, by comparing species distribution models of P. cresphontes based only on environmental data derived from other sources to models that also included the cold tolerance parameters generated experimentally. Our modelling revealed that growing degree-days and precipitation best predicted the distribution of P. cresphontes, while the cold tolerance variables did not explain much variation in habitat suitability. As such, the modelling results were consistent with our experimental results: low temperatures in autumn are unlikely to limit the distribution of P. cresphontes. Further investigation into the ecological relevance of the physiological thresholds determined here will help determine how climate limits the distribution of P. cresphontes. Understanding the factors that limit species distributions is key to predicting how climate change will drive species range shifts.

Overwintering biology and limits of cold tolerance in larvae of pistachio twig borer, Kermania pistaciella

2016 ◽  
Vol 106 (4) ◽  
pp. 538-545 ◽  
Author(s):  
M. Mollaei ◽  
H. Izadi ◽  
P. Šimek ◽  
V. Koštál
Keyword(s):  
Life Cycle ◽  
Molecular Mass ◽  
Cold Tolerance ◽  
Low Temperatures ◽  
Cold Season ◽  
High Survival ◽  
Tree Physiology ◽  
Partial Mortality ◽  
Ambient Temperatures ◽  
Important Pest

AbstractPistachio twig borer, Kermania pistaciella is an important pest of pistachio trees. It has an univoltine life-cycle and its larvae tunnel and feed inside pistachio twigs for almost 10 months each year. The last larval instars overwinter inside the twigs. Survival/mortality associated with low temperatures during overwintering stage is currently unknown. We found that overwintering larvae of the Rafsanjan (Iran) population of K. pistaciella rely on maintaining a stably high supercooling capacity throughout the cold season. Their supercooling points (SCPs) ranged between −19.4 and −22.7°C from October to February. Larvae were able to survive 24 h exposures to −15°C anytime during the cold season. During December and January, larvae were undergoing quiescence type of dormancy caused probably by low ambient temperatures and/or changes in host tree physiology (tree dormancy). Larvae attain highest cold tolerance (high survival at −20°C) during dormancy, which offers them sufficient protection against geographically and ecologically relevant cold spells. High cold tolerance during dormancy was not associated with accumulation of any low-molecular mass cryoprotective substances. The SCP sets the limit of cold tolerance in pistachio twig borer, meaning that high mortality of overwintering populations can be expected only in the regions or years where or when the temperatures fall below the average larval SCP (i.e., below −20°C). Partial mortality can be expected also when temperatures repeatedly drop close to the SCP on a diurnal basis.

The effect of diapause and cold acclimation on the cold-hardiness of the warehouse beetle, Trogoderma variabile (Coleoptera: Dermestidae)

2014 ◽  
Vol 147 (2) ◽  
pp. 158-168 ◽  
Author(s):  
Ahmed Y. Abdelghany ◽  
Duangsamorn Suthisut ◽  
Paul G. Fields
Keyword(s):  
Cold Acclimation ◽  
Cold Tolerance ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Supercooling Point ◽  
Stored Product Pest ◽  
Trogoderma Variabile ◽  
Lethal Time ◽  
Cold Hardy

AbstractThe warehouse beetle, Trogoderma variabile Ballion (Coleoptera: Dermestidae), is a stored-product pest with scant information on its cold tolerance. Ninety-two per cent of larvae reared in isolation at 30 °C went into diapause in the seventh instar, the remaining 8% emerged as adults in 50 days. Diapausing larvae died after 142 days in the 10th instar. The cold tolerance at 0 °C from highest to lowest was; old larvae>pupae>adult=young larvae>eggs. The LT50 (lethal time for 50% of the population) for grouped (non-diapause) non-acclimated old larvae at 0 °C, −5 °C, −10 °C, −16 °C, and −19 °C were; 20, 11, 5, 1, and 1 day, the LT95 were; 38, 15, 10, 5, and 1 days, respectively. The LT50 for isolated (diapausing), cold-acclimated old larvae at the same temperatures were; 275, 125, 74, 26, and 18 days, and the LT95 were; 500, 160, 100, 45, 20 days, respectively. The supercooling point (SCP) of different stages of non-acclimated insects ranged from −25.3 °C (eggs) to −16.1 °C (young larvae). The most cold hardy stage, isolated and acclimated old larvae, had a SCP of −24.9 °C. The potential of using low temperatures to control T. variabile is discussed.

Supercooling Points of Adult Dermacentor variabilis (Acari: Ixodidae) From a Population Near the Northern Distribution Limit

2020 ◽  
Author(s):  
Matthew E M Yunik ◽  
Neil B Chilton
Keyword(s):  
Cold Hardiness ◽  
Dermacentor Variabilis ◽  
Subzero Temperatures ◽  
Host Seeking ◽  
Short Period ◽  
Significant Difference ◽  
Northern Distribution ◽  
Dog Tick ◽  
Provincial Park ◽  
Established Population

Abstract The northern distributional limit of Dermacentor variabilis Say, the American dog tick, is expanding in Saskatchewan and Manitoba (western Canada). The ability of D. variabilis to continue to expand its range northwards will depend upon the ability of individuals within populations at the species distributional edge to withstand very low temperatures during winter. One component of cold hardiness is the supercooling point (SCP), the temperature below 0°C at which an individual freezes. In this study, the SCP was determined for 94 questing D. variabilis adults (44 females and 50 males) from an established population near Blackstrap Provincial Park in Saskatchewan. SCP values ranged from −18.2 to −6.7°C, with a median of −13.3°C. This suggests that host-seeking D. variabilis adults differ in their ability to survive exposure to subzero temperatures, for at least a short period of time, without freezing. The distribution of SCPs was bimodal, but there was no significant difference in SCP values between female and male ticks, and no relationship between SCP and tick body weight. It remains to be determined what factors contribute to the variation in SCP values among questing D. variabilis adults.

Desiccation and low temperature attenuate the effect of UVC254 nm in the photobiont of the astrobiologically relevant lichens Circinaria gyrosa and Buellia frigida

2014 ◽  
Vol 14 (3) ◽  
pp. 479-488 ◽  
Author(s):  
T. Backhaus ◽  
R. de la Torre ◽  
K. Lyhme ◽  
J.-P. de Vera ◽  
J. Meeßen
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Photosynthetic Activity ◽  
Real Space ◽  
Fast Recovery ◽  
Protective Mechanisms ◽  
Subzero Temperatures ◽  
High Viability ◽  
Buellia Frigida ◽  
Insight Into

AbstractSeveral investigations on lichen photobionts (PBs) after exposure to simulated or real-space parameters consistently reported high viability and recovery of photosynthetic activity. These studies focused on PBs within lichen thalli, mostly exposed in a metabolically inactive state. In contrast, a recent study exposed isolated and metabolically active PBs to the non-terrestrial stressor UVC254 nm and found strong impairment of photosynthetic activity and photo-protective mechanisms (Meeßen et al. in 2014b). Under space and Mars conditions, UVC is accompanied by other stressors as extreme desiccation and low temperatures. The present study exposed the PBs of Buellia frigida and Circinaria gyrosa, to UVC in combination with desiccation and subzero temperatures to gain better insight into the combined stressors' effect and the PBs' inherent potential of resistance. These effects were examined by chlorophyll a fluorescence which is a good indicator of photosynthetic activity (Lüttge & Büdel in 2010) and widely used to test the viability of PBs after (simulated) space exposure. The present results reveal fast recovery of photosynthetic activity after desiccation and subzero temperatures. Moreover, they demonstrate that desiccation and cold confer an additional protective effect on the investigated PBs and attenuate the PBs' reaction to another stressor – even if it is a non-terrestrial one such as UVC. Besides other protective mechanisms (anhydrobiosis, morphological–anatomical traits and secondary lichen compounds), these findings may help to explain the high resistance of lichens observed in astrobiological studies.

Thermal Property Measurements on Biological Materials at Subzero Temperatures

1991 ◽  
Vol 113 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Xuemei Bai ◽  
David E. Pegg
Keyword(s):  
Thermal Conductivity ◽  
Low Temperatures ◽  
The Self ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Low Viscosity ◽  
Subzero Temperatures ◽  
Liquid Samples ◽  
Thermal Probes ◽  
Low Ionic Strength

The self-heated thermistor technique was used to measure the thermal conductivity and thermal diffusivity of biomaterials at low temperatures. Thermal standards were selected to calibrate the system at temperatures from −10°C to −70°C. The thermal probes were constructed with a convection barrier which eliminates convection inside liquid samples of low viscosity, without affecting the conductivity and diffusivity results. Using this technique, the thermal conductivity and diffusivity of two organ perfusates (HP5 and HP5 + 2M glycerol), one kidney phantom (a low ionic strength gel), as well as rabbit kidney cortex have been measured from −10°C to −70°C.

Flower cold hardiness: a potential determinant of the flowering sequence exhibited by bog ericads

1979 ◽  
Vol 57 (9) ◽  
pp. 997-999 ◽  
Author(s):  
R. J. Reader
Keyword(s):  
Low Temperatures ◽  
Cold Hardiness ◽  
Vaccinium Macrocarpon ◽  
Southern Ontario ◽  
Air Temperatures ◽  
Insect Pollinators ◽  
Cold Hardy ◽  
Vaccinium Myrtilloides ◽  
Potential Determinant ◽  
Ledum Groenlandicum

In laboratory freezing trials, cold hardiness of six types of bog ericad flowers differed significantly (i.e., Chamaedaphne calyculata > Andromeda glaucophylla > Kalmia polifolia > Vaccinium myrtilloides > Ledum groenlandicum > Vaccinium macrocarpon) at air temperatures between −4 and −10 °C but not at temperatures above −2 °C. At the Luther Marsh bog in southern Ontario, low temperatures (−3 to −7 °C) would select against May flowering by the least cold hardy ericads. Availability of pollinators, on the other hand, would encourage May flowering by the most cold hardy species. Presumably, competition for insect pollinators has promoted the diversification of bog ericad flowering peaks, while air temperature, in conjunction with flower cold hardiness, determined the order in which flowering peaks were reached.

Irrigation and crop improvement in temperate and tropical environments

1986 ◽  
Vol 316 (1537) ◽  
pp. 319-330 ◽  
Keyword(s):  
Life Cycle ◽  
Low Temperatures ◽  
Energy Use ◽  
Crop Improvement ◽  
Yield Potential ◽  
Multiple Cropping ◽  
Tropical Environments ◽  
Physiological Processes ◽  
Seasonal Signals ◽  
The Tropics

There is a strong interaction between irrigation and crop improvement, irrigation creating new opportunities and challenges for plant breeders while depending on their progress for its full benefits to be realized. In temperate environments the primary emphasis is on raising yield potential, especially as irrigation enhances the use of agrichemical inputs. Efficiency of water and energy use through the modification of physiological processes and of sensitivity to stress at various stages of the life cycle is also sought. In tropical environments, breeding for greater yield potential and more comprehensive pest and disease resistance are still important. However, shortening the length of the life cycle, reducing its sensitivity to seasonal signals and increasing yield per day may be more important than raising yield per crop because of the scope for multiple cropping made possible by irrigation in the tropics in the absence of contraints by low temperatures.

scholarly journals Nematode Hsp90: highly conserved but functionally diverse

Parasitology ◽  
2014 ◽  
Vol 141 (9) ◽  
pp. 1203-1215 ◽  
Author(s):  
VICTORIA GILLAN ◽  
EILEEN DEVANEY
Keyword(s):  
Life Cycle ◽  
Heat Shock Protein 90 ◽  
Ecological Niches ◽  
Actual Number ◽  
Host Organism ◽  
Free Living ◽  
Parasitic Species ◽  
Free Living Nematode ◽  
Functionally Diverse

SUMMARYNematodes are amongst the most successful and abundant organisms on the planet with approximately 30 000 species described, although the actual number of species is estimated to be one million or more. Despite sharing a relatively simple and invariant body plan, there is considerable diversity within the phylum. Nematodes have evolved to colonize most ecological niches, and can be free-living or can parasitize plants or animals to the detriment of the host organism. In this review we consider the role of heat shock protein 90 (Hsp90) in the nematode life cycle. We describe studies on Hsp90 in the free-living nematode Caenorhabditis elegans and comparative work on the parasitic species Brugia pahangi, and consider whether a dependence upon Hsp90 can be exploited for the control of parasitic species.

Sign in / Sign up

Export Citation Format

Share Document