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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
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
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
Transfer Code of Practice
Get PDFUpdate on the Transfer Code of Practice, which is now under the umbrella of NISO
Tapped: An Inside Perspective on the Craft Beer Movement
Get PDFAn ethnography of participants of the craft beer movement. This work investigates how craft beer is consumed, how it is made, and what it means to society