Studies on insect dormancy. II. Relationship of cold-hardiness to diapause and quiescence in the eastern tent caterpillar, Malacosoma americanum (Fab.), (Lasiocampidae: Lepidoptera)

1974 ◽  
Vol 52 (5) ◽  
pp. 629-637 ◽  
Author(s):  
Ajai Mansingh

Studies were conducted on the relationship between levels of glycerol and carbohydrates, supercooling points, and the relative abilities of diapausing and developing eggs and of larval instars of Malacosoma americanum to withstand various periods of chilling at 5° and −15 °C.Diapause in the mature embryos was associated with very high glycerol content (112 mg/g), low carbohydrate level (13 mg/g), and the ability to supercool to −35 °C. During diapause termination, the glycerol level was reduced lo 11 mg/g with a slight rise only in carbohydrate level while the supercooling point was raised to −14 °C. When quiescence was induced in the larvae by chilling them at 5 °C for 1 to 7 weeks, their wet weights and carbohydrate and glycerol contents decreased gradually. However, the supercooling point remained constant around −14 °C.Diapausing embryos could survive several weeks of chilling at −15° and 5 °C. However, only a few weeks of exposure to 5 °C was fatal to quiescent larvae.It is concluded that there is a direct relationship between glycerol content, supercooling points, and the relative abilities of developing and diapausing stages of the tent caterpillar to withstand low temperatures. The developing stages were naturally "cold-tolerant" with the ability to supercool to −14 °C and survive a few weeks of quiescence at 5 °C, which is well below their range of physiological adaptation. Induction of diapause enhanced the supercooling ability and increased cold-hardiness in the mature embryos.

1993 ◽  
Vol 125 (6) ◽  
pp. 1043-1053 ◽  
Author(s):  
Er-Ning Han ◽  
Eric Bauce

AbstractSupercooling point, biochemical metabolites, and water content of the larvae of Choristoneura fumiferana (Clem.) were measured during pre-diapause and diapause development under laboratory conditions. Supercooling point dropped significantly, from a mean value of −22.9 °C to −31.7 °C during the 3-week pre-diapause development. Supercooling point continued to decline down to −34.5 °C after the beginning of diapause. Water content also dropped significantly during pre-diapause development and was maintained at a low level during diapause. Significant amounts of glycerol were detected only when the larvae were 5 weeks into diapause and the glycerol level continued to increase until week 20 when it was almost 10 times its original level. Glycogen was nearly depleted after diapause, but lipid remained at a relatively high level. Little change in glucose and trehalose content was found during diapause in spite of their initial rise before diapause. Larvae could survive low temperatures close to their supercooling point without freezing but none survived freezing, suggesting that this species is freeze-intolerant. First-instar larvae were found to excrete green material out of their body within 5 days after emergence. Removal of this material from the insect body coincided with a significant drop in supercooling point, indicating that a potential nucleating factor might be involved in the green material. The implications of these results for the overwintering strategy of C. fumiferana are discussed.


2012 ◽  
Vol 58 (7) ◽  
pp. 897-902 ◽  
Author(s):  
Marjan Bemani ◽  
Hamzeh Izadi ◽  
Kamran Mahdian ◽  
Abbas Khani ◽  
Mohammad Amin samih

1993 ◽  
Vol 71 (8) ◽  
pp. 1511-1515 ◽  
Author(s):  
T. D. Fitzgerald ◽  
F. X. Webster

Behavioral assays show that the steroid 5β-cholestan-3-one, isolated from the abdomen of the larva of the forest tent caterpillar (Malacosoma disstria), constitutes the chemical basis of trail following in this insect. Caterpillars follow artificial trails prepared from solvent dilutions of the compound at rates as low as 10−11 g∙mm−11 of trail, though the true threshold sensitivity is likely to be one or two orders of magnitude lower than this. Fourth-instar caterpillars store an average of 58 ng of the pheromone. Field and laboratory studies indicate that the compound is fully competitive with their authentic trails. The caterpillars are highly sensitive to differences in the concentration of the pheromone, preferring stronger trails to weaker trails. The caterpillars also respond to 5β-cholestane-3,24-dione, a chemical not found in M. disstria but known to be a component of the trail pheromone of the eastern tent caterpillar, Malacosoma americanum.


1991 ◽  
Vol 69 (12) ◽  
pp. 3028-3037 ◽  
Author(s):  
Olga Kukal ◽  
Matthew P. Ayres ◽  
J. Mark Scriber

A steep decline in the diversity of swallowtail butterfly species at high latitudes could be due to limited cold tolerance of overwintering pupae. If this is so, species with unusually northerly distributions should be unusually cold tolerant. We compared the northerly distributed Papilio canadensis with its southern relative, P. glaucus. Pupae were exposed for 2–5 months to four acclimatization treatments: outdoors in Alaska, outdoors in Michigan, constant 5 °C, and constant −25 °C. Field temperatures encountered by pupae in Alaska were lower than in Michigan. The supercooling point of P. glaucus pupae was unaffected by acclimatization (mean ± SE= −23.5 ± 0.52 °C). The supercooling point of P. canadensis pupae did not differ from that of P. glaucus pupae, except following acclimatization in Alaska, when it dropped to −27.0 ± 0.55 °C. Survival of pupae in Michigan was high for all populations (70–90%); in Alaska, survival of P. canadensis was just as high, but survival of P. glaucus dropped to 14%. Freezing was usually fatal in both species, but death was not immediate. No pupae survived 6 weeks at −25 °C. Trehalose was the most conspicuous metabolite revealed by nuclear magnetic resonance spectroscopy of live pupae and hemolymph. Labelled glucose was metabolized differently by the two species, which may underly the difference in acclimation potential and cold tolerance. The results support the hypothesis that winter temperatures limit swallowtail distributions.


1993 ◽  
Vol 71 (4) ◽  
pp. 759-764 ◽  
Author(s):  
Thierry Hance ◽  
Guy Boivin

The cold hardiness of egg parasitoids is critical to their survival in winter because these organisms have little control in the choice of their overwintering site. The supercooling points of Listronotus oregonensis eggs increased from −24.9 to −22.1 °C as eggs matured. When these eggs were parasitized by Anaphes sp., their supercooling point remained stable at −22.9 °C throughout the development of the parasitoid. Anaphes sp. maintained its cold hardiness by increasing its levels of glycerol and fructose. When the parental generation was exposed to a combination of low temperature and short photoperiod, the supercooling point of the daughter generation (F1) was significantly decreased. A further decrease in the supercooling point was observed when F1 individuals were stored at 3 °C for 14 or 20 days. These data show that local extinction of populations overwintering in nonsheltered habitats is probably common in southwestern Quebec.


2015 ◽  
Author(s):  
Stefanos S Andreadis ◽  
Yianna Poulia ◽  
Sofia Noukari ◽  
Barbara Aslanidou ◽  
Matilda Savopoulou-Soultani

The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is a worldwide pest of solanaceous crops especially devastating to potatoes. In the present study we investigated the cold hardiness profile of short-term acclimated and non-acclimated immature and adult stages of a field population of P. operculella. Late instars displayed the lowest mean supercooling point, for both short-term acclimated and non-acclimated individuals, however, no significant differences were observed among developmental stages. Unlike supercooling capacity, acclimation at 5 oC for 5 days enhanced the ability to survive at subzero temperatures after a 2 h exposure. Mean lethal temperature (LTemp50) of all developmental stages (egg, late instar, pupa and adult) decreased after short-term acclimation, however only adults displayed a significant difference among acclimated and non-acclimated individuals concerning their LTemp50 (-11.1 and -8.3 oC, respectively). Generally, pupae were the most cold tolerant developmental stage followed in decreasing order by the eggs and adults, while interestingly late instars were the least ones. Non-freezing injury above the supercooling point was well documented for all developmental stages indicating a pre-freeze mortality and suggesting that P. operculella is considered to be chill tolerant rather than freeze intolerant. Nevertheless, given its high degree of cold hardiness, winter mortality of P. operculella due to low temperatures is not likely to occur and potential pest outbreak can take place following a mild winter.


2020 ◽  
Vol 113 (3) ◽  
pp. 1254-1261
Author(s):  
Jiahe Pei ◽  
Chengcheng Li ◽  
Lili Ren ◽  
Shixiang Zong

Abstract Streltzoviella insularis (Staudinger) (Lepidoptera: Cossidae) is a woodboring pest that severely damages urban and plain afforestation trees in northern China. Cold hardiness is an important strategy for the insect to survived during low winter temperatures. Understanding the strategy of S. insularis might provide insights for pest management approaches. To assess the key factors affecting cold hardiness, we measured the supercooling point, freezing point, total water content, total fat content, glycogen content, and total protein content of overwintering larvae. The relationships between supercooling points, temperature, body size, and nutrients were analyzed. The results showed that the supercooling point and freezing point of the larvae decreased first, reached the lowest point in January, and then increased during the rest of the overwintering period. The supercooling point positively correlated with the daily average temperature and the daily minimum temperature. Total lipid content negatively correlated with the supercooling point, while glycogen content had a significant positive correlation with the supercooling point. The temperature may have a major impact on cold hardiness, whereas individual body size may have no significant influence over cold tolerance. During the overwintering process, glycogen and total lipid contents may directly affect cold hardiness. Therefore, the lipid and carbohydrate metabolism may play a role in the cold tolerance of S. insularis larvae. This study provides a physiological and biochemical basis for future metabolic studies on S. insularis larva and the research of overwintering strategies.


1964 ◽  
Vol 42 (1) ◽  
pp. 87-101 ◽  
Author(s):  
Lauritz Sømme

The effects of glycerol on cold-hardiness in insects and seasonal changes in glycerol concentrations were investigated. The presence of this polyhydric alcohol was demonstrated in overwintering stages of 10 species. Larvae of one species also contained sorbitol, and eggs of two species another polyhydric alcohol, probably mannitol.Evidence gathered from various diapausing species showed that glycerol accumulated during the fall. This increase in concentration was observed in eggs of one species at temperatures ranging from −5° to 20 °C. No decrease in glycerol content was observed in any species as long as it was in diapause. After diapause was broken glycerol was lost in all species, in some even at temperatures down to −5 °C. Increase in concentration was never found in postdiapause insects. In two species, which do not have a diapause, the glycerol content increased below a certain temperature and decreased at higher temperatures.Three species were freezing-tolerant, although one contained less than 3% and another no glycerol, whereas eight species, most of which contained more than 15%, were killed by freezing. Thus glycerol alone cannot protect against freezing injuries.In several species the cold-hardiness was increased by the presence of glycerol because supercooling points were depressed. These depressions were more than those of the corresponding melting points. The regression of amount of supercooling on concentration of glycerol was linear in five species.


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