Miami University, Ohio
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Anatomic site of application of ice-nucleating active bacteria affects supercooling in the Colorado potato beetle (Coleoptera: Chrysomelidae)
Get PDFMost overwintering insects do not survive internal freezing and must avoid low temperatures or enhance the capacity of their body fluids to supercool to survive low temperature exposure. Recent reports have demonstrated that the application of ice-nucleating active microorganisms markedly diminishes supercooling. Topical application of as little as 20 ppm of a suspension of a freeze-dried preparation of the ice-nucleating active bacterium Pseudomonas syringae van Hall was sufficient to elevate the mean supercooling point of the overwintering adults of the Colorado potato beetle, Leptinotarsa decemlineata (Say), from −8.7 to −4.7°C. Previous reports have demonstrated that topical application of these biological ice nucleators to insects whose mouths have been sealed still reduces supercooling capacity; however, the anatomical route by which these agents make contact with body water is unclear. Application of the P. syringae suspension to the ventral abdomen did not significantly increase the supercooling point (−5.5°C) compared with beetles treated with the non-ice-nucleating active (control) bacterium Escherichia coli (Migula). However, application of the ice-nucleating agent to the thoracic spiracle, ventral cervix, or abdominal spiracle elevated supercooling point values above those of beetles treated on the ventral abdomen. These data are instructive in the development of methods for the use of ice-nucleating active microorganisms for the biological control of overwintering pests
Cold-hardiness of a laboratory colony of lone star ticks.
Get PDFThe cold-hardiness of a lone star tick, Ambylomma americium (L.) laboratory colony was characterized. Fed and unfed larvae, fed and unfed nymphs, and unfed adults did not survive exposure to -17C for 7 d. After an 8-d exposure to -10C, adults tolerated cold better than immatures and unfed specimens fared better than fed ticks. Exposing unfed 6-wk old (post mold) adult males and females to -15C for increasing intervals up to 2 hrs suggests that males were more tolerant to cold then were females. Half of all adults were alive 3 d after the 2-h low-temperature treatment. Males may have survived because of a significantly higher hemolymph osmotic pressure, although the solute concentration increased for both sexes after a 2-h exposure to 0C. Acclimation to 5C for 7 d had no influence on supercooling points for unfed males and females, engorged nymphs and larvae, and eggs. None of the life stages survived supercooling, which strongly suggests that this species is freeze-intolerant. Intolerance of immature stages to chilling may be a limiting factor in the northern distribution of lone star ticks in North America
Cryobiology of the freeze-tolerant gall fly Eurosta solidaginis: Overwintering energetics and heat shock proteins.
No full textThe goldenrod gall fly Eurosta solidaginis (Diptera: Tehritidae) ranges from the southern U.S. northward into Canada. The larvae overwinters with a ball gall on the stem of goldenrod Solidago spa. The galls often extend above the snowpack, exposing the larva to a wide range of environmental extremes in winter. This species has received extensive attention as a freeze-tolerent insect model. A seasonal study of the overwintering bioenergetics of an Ohio, USA, population revealed marked decreases in body weight, lipid and total caloric content in October and November when environmental temperatures were the highest. Overwintering larvae produced heat-shock proteins in response to high-temperature exposure. However, unlike other insects E. solidaginis does not appear to synthesize head-shock proteins in response to low-temperature exposure
Adaptations of frogs to survive freezing
Get PDFFive species of frogs from North America survive extensive freezing of their body fluids to temperatures as low as -8C for periods lasting at least 2 weeks. These frogs hibernate in leaf litter where subzero temperatures commonly occur during the winter. The onset of freezing triggers liver glycogenolysis and the production of high concentrations of glucose or glycerol (to 100x normal) that functions as a cryoprotectant against freezing injury. Concomitantly the release of the latent heat of crystallization as body water freezes promotes the continued function of the cardiovascular system for many hours, and serves to distribute glucose throughout the body. The water content of major organs is reduced by 50% or more during the first 24 hours of freezing, with the water being relocated and frozen in other body spaces. Organ dehydration functions to concentrate cryoprotectant and the reduce mechanical damage by ice during freezing. As freezing progresses, breathing, heart beat, and most other vital functions cease, but reanimation occurs within a few hours after thawing. The evolution of freeze tolerance in these animals illustrates the highly flexible capacities of frogs to adapt to stressful environments
Cold hardiness and overwintering strategies of hatchlings in an assemblage of northern turtles.
Get PDFField and laboratory studies were conducted during 1989-1994 to investigate the overwintering strategies of hatching turtles representing four families native to western Nebraska. Whereas hatchling snapping turtles (Chelydra serpentina) and spiny soft-shelled turtles (Apalone spinifera) overwinter in aquatic habitats, yellow mud turtles (Kinosternon flavescens) and ornate box turtles (Terrapene ornata) burrow below the natal nest and hibernate in sandy soil. Painted turtles (Chrysemys picta) overwinter within their shallow natal nests, but this species, and T. ornata, tolerate extensive tissue freezing. Overwintering behaviors of these species are consistent with indices of physiological cold hardiness and patterns of geographic distribution. Frost commonly penetrated and persisted below 10 cm, the soil depth as which hatchling C. picta routinely hibernate. Field and laboratory data suggested that hatchling C. picta survive either by remaining super-cooled (unfrozen) or by tolerating tissue freezing, the strategy employed depending on prevailing physiological and microenvironmental conditions. Whereas relatively lower temperatures can be survived in the supercooled state, supercooling capacity may be limited via the inoculation of body fluids by environmental ice. Alternatively, wheras freeze tolerence fortuitously is promoted by ice inoculation, this strategy may be viable only at relatively high subzero temperatures. A cold-hardiness stragefy based on both survival mechanisms may promote winter survival in hatchling C. picta by conferring protection under dynamic physiological and microenvironmental conditions. Physiological cold hardiness and behavior are integrated determinants of the northern distributions of temperature region turtles
Cryobiology of the freeze-tolerent gall fly Eurosta solidaginis: overwintering energetics and heat shock proteins
No full textThe goldenrod gall fly E urosta solidaginis (Diptera: Tephritidae) ranges from
the southern us. northward into Canada. The larva overwinters within a ball gall on the stem
of goldenrod Solidago spp. The galls often extend above the snowpack, exposing the larva to a wide range of environmental extremes in winter. This species has received extensive attention as a freeze-tolerant insect model. A seasonal study of the overwintering bioenergetics of an Ohio, USA population revealed marked decreased in body weight, lipid and total caloric content in October and November, when environmental temperatures were the highest. Overwintering larvae produce heat shock proteins in responses to high temperature exposure. However, unlike other insects E. solidagnis does not appear to synthesize heat shock proteins in response to low-temperature exposure
Ice nucleating active bacteria reduce the cold-hardiness of the freeze-intolerant Colorado potato beetle (Coleoptera: Chrysomelidae).
No full textIn laboratory experiments, a freeze-dried concentrated form of the icenucleating active bacteria, Pseudomonas syringae, was used to decrease the supercooling capacity of field-collected diapausing Colorado potato beetles, Leptinotarsa decemlineata (Say). Application of the P. syringae to adult beetles increased their mean supercooling point values from −7.6 ± 0.2°C (untreated) to −3.7 ± 0.1°C (1,000 ppm). No beetles survived cooling to temperatures below their supercooling point, indicating that this species is freeze-intolerant. During tests conducted in 1991 and 1992, the increase in the supercooling point was directly dependent on the amount of P. syringae added to soil containing the beetles. Cumulative freezing distributions indicated that 80% of beetles treated with 100ppm of P. syringae would be expected to freeze and die when exposed to −5°C; in contrast, none or very few of the untreated control beetles would be expected to freeze at this temperature. Other experiments demonstrated that the capacity of P. syringae treatments to increase the supercooling point of the beetles decreased after 2 wk of exposure at 4°C and when experiments were done at 10°C. If delivery systems were developed that would expose adult beetles to ice nucleating agents and preserve their ice nucleating activity until critical low-temperature exposure occurs in mid-winter, these nucleating agents could be used in conjunction with cultural control strategies for increasing winter mortality
Topical application of ice-nucleating-active bacteria decreases insect cold tolerance
Get PDFThe majority of overwintering insects avoid lethal freezing by lowering the temperature at which ice spontaneously nucleates within their body fluids. We examined the effect of ice-nucleating-active bacteria on the cold-hardiness of the lady beetle, Hippodamia convergens, a freeze-intolerant species that overwinters by supercooling to ca. −16°C. Topical application of the ice-nucleating-active bacteria Pseudomonas syringae increased the supercooling point to temperatures as high as −3°C. This decrease in cold tolerance was maintained for at least 3 days after treatment. Various treatment doses (108, 106, and 104 bacteria per ml) and modes of action (bacterial ingestion and topical application) were also compared. At the highest concentration of topically applied P. syringae, 50% of the beetles froze between −2 and −4°C. After topical application at the lowest concentration, 50% of the individuals froze by −11°C. In contrast, beetles fed bacteria at this concentration did not begin to freeze until −10°C, and 50% were frozen only at temperatures of −13°C or less. In addition to reducing the supercooling capacity in H. convergens, ice-nucleating-active bacteria also significantly reduced the cold-hardiness of four additional insects. These data demonstrate that ice-nucleating-active bacteria can be used to elevate the supercooling point and thereby decrease insect cold tolerance. The results of this study support the proposition that ice-nucleating-active bacteria may be used as a biological insecticide for the control of insect pests during the winter
Surviving the big chill: overwintering strategies of aquatic and terrestrial insects.
Get PDFThe purpose of this paper is to describe the cold-hardiness of aquatic insects and to use the literature to compare physiological and behavioral strategies that aquatic and terrestrial insects use to cope with minimum winter temperatures. In sharp contrast to terrestrial insects, aquatic insects from seven different orders had limited ability to supercool and did so to temperatures of only −3 to −7°C. Inability to supercool may be due to inoculative freezing—the penetration of external ice crystals through pores or orifices of the insect's cuticle. Furthermore, our results suggest that terrestrial adult stages of aquatic insects may have greater capacity to supercool than aquatic stages of the same taxon. Our results and others' suggested that few aquatic species are freeze tolerant, and those that are appear to be restricted to the order Diptera. Consequently, behavioral avoidance of ice or the capacity to remain unfrozen while encased in ice may be particularly important for overwintering aquatic insects. Ecological implications of insect coldhardiness at the individual, population, and community level are discussed for both terrestrial and aquatic insects
Ice-nucleating active bacteria decrease the cold-hardiness of stored grain insects.
No full textThis report provides further evidence that a freeze-dried, concentrated form of Pseudomonas syringae, an ice-nucleating active bacteria, reduces the cold tolerance of stored grain insect pests. Application of ice-nucleating bacteria to wheat or corn that contained insect pests decreased the insects’ supercooling capacity: after treatment with 100 ppm of P. syringae the mean supercooling points of five insect species increased from 4.7 to 11.9°C above untreated controls. Treatment with P. syringae also decreased the capacity of insects to survive a 24-h exposure to subzero temperatures. Decreases in cold tolerance were observed in eight species of stored grain pests: Indianmeal moth larvae, Plodia interpullctella (Hubner); red flour beetle adults, Tribolium castaneum (Herbst); flat grain beetle adults, Cryptolestes pusillus (Schon herr); rusty grain beetle adults, Cryptolestes ferrugineus (Stephens); Gibbium psylloides (Czenpinski); lesser grain borer adults, Rhyzopertha dominica (F.); yellow meal worm larvae, Tenebrio molitor (L.); and granary weevil adults, Sitophilus granariusgranarius (L.). Results of this study provide further support for the use of ice-nucleating active bacteria as biological insecticides to kill overwintering insects by decreasing their low temperature tolerance. The approach may be particularly appropriate for the control of a variety of insect pests in restricted areas such as grain bins