Escaping an ecological dead-end: asexual overwintering and morph determination in the lettuce root aphid Pemphigus bursarius L.

1. Pemphigus bursarius exhibits a host-alternating life-cycle, overwintering as eggs on the primary host plant (poplar) before migrating in summer to the secondary host plant (mainly annual Compositae). A proportion of the population does not produce return migrants (sexuparae) in the autumn but remains in the soil and overwinters as asexual apterae, even after the annual plants have died in early winter. Laboratory and field experiments investigated the biology and overwintering success of these asexual apterae. 2. Both temperature and photoperiod are important in morph determination. The highest number of apterae (approximately 50% of progeny) was produced in a 20 °C, LD 18 : 6 h regime. Very few apterae were produced in an alatae-inducing environment (15 °C, LD 12 : 12 h), but the proportion increased over successive generations. 3. Apterae remaining in the soil in the autumn overwintered successfully in large numbers and were able to reinfest directly the root systems of newly planted lettuce grown in the same field in the following growing season. 4. Overwintered asexual populations also produced alates in July, which were able to colonise other lettuce plants, indicating that they were not sexuparae. Hence, P. bursarius can avoid the ecological dead-end that would occur through local patch extinction. Clones can therefore persist indefinitely as both asexual apterae and alatae without the need to return to poplar and undergo the sexual phase of the life-cycle.     

Seasonal variation in freeze tolerance and ice content of the tree frog Hyla versicolor

Freeze tolerance and ice content of Hyla versicolor showed pronounced variation between summer (June) and winter (December). Summer frogs survived freezing at -3 degrees C for up to 9 hr and ice accumulation up to 50% of their total body water. A time course of ice formation indicated that an equilibrium level was reached in approximately 15 hr. Thus, the lethal ice content was less than the equilibrium ice content for these conditions (63.1%). A second group was induced to enter an overwintering condition by holding them through the summer and then subjecting them to a progressive reduction in temperature and photoperiod for 2 months. These frogs survived freezing for 48 hr at -3 degrees C. Their equilibrium ice content at this temperature was significantly lower (52.5%) than comparably treated summer animals. In the winter acclimatized group, frozen frogs had substantially higher blood glucose levels than unfrozen frogs (22.7 mumol/ml vs. 1.33 mumol/ml), but glycerol levels were not elevated after freezing. Freezing frogs conditioned for overwintering at -7 degrees C resulted in a higher equilibrium ice content (62.6%), but none survived. It is evident that in preparation for overwintering, frogs reduce the amount of ice formed at a given subzero temperature, but there is little indication of a substantial change in the total amount of ice tolerated.     

Seasonal changes in tolerance to cold and desiccation in Phauloppia sp. (Acari, Oribatida) from Finse, Norway

In the alpine region at Finse, Norway, Phauloppia spp. (Acari, Oribatida) inhabit lichens on top of boulders. Adult mites are about 0.5 mm in length and have a mean weight of ca. 15 μg. Temperatures in the lichens may drop below -35 degrees C in winter and increase to 55 degrees C in the summer. Large seasonal variations were recorded in supercooling points and body fluid osmolality. Mean January values of SCPs and osmolality were -35.3 degrees C and 3756 mOsm, while July values were -9.4 degrees C and 940 mOsm, respectively. Thermal hysteresis proteins were present in both summer and winter acclimated mites. In mid-winter, some of the mites survived more than 49 days in a water vapor saturated atmosphere at -19 degrees C, and more than 42 days enclosed in ice at the same temperature.The mites showed high tolerance to desiccation. Specimens collected in October survived up to 23 days at 22 degrees C and 5% RH. The tolerance to desiccation was lower in specimens collected during the winter. Some mites survived the loss of up to 90% of their total water content and were reactivated when given access to water. Length measurements of individual Phauloppia sp. showed that both male and female mites are clearly divided in two size groups, suggesting that they belong to two closely related species or different populations.     

Factors affecting the freeze tolerance of the hoverfly Syrphus ribesii (Diptera: syrphidae)

Larvae of Syrphus ribesii collected from overwintering sites in the U.K. are strongly freeze tolerant with 70% survival at -35 degrees C. The cold tolerance of laboratory reared insects increased with increasing periods of acclimation at 0 degrees C, with a concurrent rise in the supercooling point (SCP) from -6.8+/-0.1 to -5.1+/-0.3 degrees C. There was 50% survival in the most cold-hardy group 72h after brief exposures to -30 degrees C. The retention of gut contents caused a decrease in cold hardiness, with only 13% of larvae surviving 72h after exposure to -15 degrees C, with no subsequent pupation or emergence. Wet larvae had a significantly higher SCP (-5.0+/-0.2 degrees C) compared to dry larvae (-7.8+/-0.4 degrees C), although survival of larvae was similar in both groups. There was no nucleator activity in the haemolymph of field collected larvae. The importance of these findings are discussed in relation to the freeze tolerance strategy of S. ribesii.     

Overwintering strategy in Pyrrhocoris apterus (Heteroptera): the relations between life-cycle, chill tolerance and physiological adjustments

Seasonal dynamics of ecophysiological parameters are described which are relevant to overwintering in field-collected adults of a Czech population of the red firebug, Pyrrhocoris apterus. Five life-cycle phases were distinguished using the duration of pre-oviposition period as a criterion: reproductive activity (spring-early summer), intensification of reproductive diapause (RD) (peak of summer), maintenance of RD (late summer-early autumn), termination of RD (late autumn-early winter), and low temperature quiescence (LTQ) (winter). The supercooling capacity and chill tolerance (c.t.) increased simultaneously with the termination of RD and all three processes were triggered/conditioned by autumnal decrease in ambient temperatures. Maximum supercooling capacity and c.t. 'outlived' the end of diapause and persisted throughout the LTQ state. The limits of c.t. were estimated as -15 degrees C/1-2 weeks for 50% survival. Ribitol, sorbitol, arabinitol, and mannitol were accumulated in the winter-sampled insects. Relatively low concentrations of polyols (dominating ribitol reached ca. 1% FW) indicate that they do not function as colligative cryoprotectants. However, because their seasonal occurrence coincided with the highest c.t., their non-colligative cryoprotectant effects would merit further study. Although the overwintering microhabitat of P. apterus is buffered, the temperatures may fall to -13 degrees C during exceptionally cold winters and thus, the parameters of c.t. seem to be just appropriately tuned to the local overwintering conditions.     

Overwintering Strategy and Mechanisms of Cold Tolerance in the Codling Moth (Cydia pomonella)

Background

The codling moth (Cydia pomonella) is a major insect pest of apples worldwide. Fully grown last instar larvae overwinter in diapause state. Their overwintering strategies and physiological principles of cold tolerance have been insufficiently studied. No elaborate analysis of overwintering physiology is available for European populations.

Principal Findings

We observed that codling moth larvae of a Central European population prefer to overwinter in the microhabitat of litter layer near the base of trees. Reliance on extensive supercooling, or freeze-avoidance, appears as their major strategy for survival of the winter cold. The supercooling point decreases from approximately −15.3°C during summer to −26.3°C during winter. Seasonal extension of supercooling capacity is assisted by partial dehydration, increasing osmolality of body fluids, and the accumulation of a complex mixture of winter specific metabolites. Glycogen and glutamine reserves are depleted, while fructose, alanine and some other sugars, polyols and free amino acids are accumulated during winter. The concentrations of trehalose and proline remain high and relatively constant throughout the season, and may contribute to the stabilization of proteins and membranes at subzero temperatures. In addition to supercooling, overwintering larvae acquire considerable capacity to survive at subzero temperatures, down to −15°C, even in partially frozen state.

Conclusion

Our detailed laboratory analysis of cold tolerance, and whole-winter survival assays in semi-natural conditions, suggest that the average winter cold does not represent a major threat for codling moth populations. More than 83% of larvae survived over winter in the field and pupated in spring irrespective of the overwintering microhabitat (cold-exposed tree trunk or temperature-buffered litter layer).     

Physiology of Hibernating Larvae of the Pistachio Twig Borer, <Emphasis Type="Italic">Kermania pistaciella</Emphasis> Amsel (Lepidoptera: Tineidae), Collected from Akbari Cultivar of <Emphasis Type="Italic">Pistacia vera</Emphasis> L.

The pistachio twig borer, Kermania pistaciella Amsel (Lepidoptera: Tineidae), a key pest of pistachio trees, is a monovoltine pest living inside the feeding tunnel of pistachio twigs for almost 10 months in a year and overwinters there as last instar larvae. In this study, we measured some physiological parameters of overwintering field collected larvae of the pest. There were no changes in trehalose, glucose, and myo-inositol contents, but there were differences in the levels of total simple sugar and glycogen during overwintering. Total sugar content at the beginning of overwintering (October) was at the lowest level (24.13 mg/g body weight) and reached to the highest level (55.22 mg/g fresh body weight) in November whereas glycogen content was at the highest level (44.05 mg/g fresh body weight) in October and decreased to 18.42 mg/g fresh body weight in November. Decrease in lipid content during the overwintering period was not significant. The highest and lowest levels of protein content were recorded in January and February, respectively. Supercooling points (SCP) of the overwintering larvae were stable and low (ranged between ?17.80 and ?25.10°C) throughout the cold season and no larva survived after SCP determination. The lowest cold hardiness (60 and 0.0% survival following exposure to ?10 and ?20°C/24 h, respectively) was observed for in November-collected larvae. Overwintering larvae of the pistachio twig borer rely mostly on maintaining the high supercooling capacity throughout the overwintering to avoid freezing of their body fluid.     

Cold tolerance of the aphid predator Episyrphus balteatus (DeGeer) (Diptera, Syrphidae)

Abstract. Larvae of the hoverfiy Episyrphus balteatus (DeGeer) are important predators of aphids in the U.K. A large proportion of the U.K. population migrates south to warmer climes at the end of summer, but a small number are thought to overwinter in the U.K., with the mated female being the overwintering morph. The cold tolerance of adult flies was investigated to assess the overwintering potential of E. balteatus in the U.K. The high supercooling point (SCP) of -8.3 ± 0.7°C, and lethal temperature (LTemp₃₀) of -9.1°C for acclimated females suggest that E. balteatus has limited cold hardiness. This was confirmed by experiments where, despite a strong acclimation response in both males and females, there was no long-term survival at 5, 0 or - 5°C. At 5°C, 90% of females had died after 10 days. The weak cold hardiness of adult E. balteatus was corroborated by field experiments which demonstrated a 100% mortality after 10 weeks' exposure to U.K. winter conditions. The ecological significance of this limited cold hardiness is discussed in relation to the overwintering abilities of E. balteatus in the U.K.     

Simulated winter to summer transition in diapausing adults of the lady beetle (Hippodamia convergens): supercooling point is not indicative of cold-hardiness

ABSTRACT. Adults of Hippodamia convergens Guerin-Meneville (Coleoptera: Coccinellidae) form massive overwintering aggregations in the Sierra Nevada Mountains of California. These diapausing pre-reproductive adults may remain in the aggregations for up to 10 months. Beetles were collected from overwintering sites in Nevada County, California, and held at 4C for 6 weeks. In order to simulate the winter to summer transition, the beetles were transferred to 20C and 68% r.h. under a LD 12:12h cycle. Supercooling points increased slightly from - 16C on day 0 to - 12.9CC on day 21. In contrast, low temperature tolerance decreased markedly within 2 weeks. On day 0 nearly all beetles survive 2 h of exposure to - 5C, whereas only 50% survived this treatment on day 4. These data demonstrate the general lack of correlation between the supercooling point and the lower lethal temperature in warm-acclimated beetles. Within 1 day of transfer to 20C, oxygen consumption decreased by 26%. This decrease continued through day 14 when the rate of oxygen consumption had decreased to 40% of initial values. Beetles acclimated to 20C selected temperatures significantly higher than cold-acclimated beetles. The parametric shifts observed in this study are consistent with a physiological transition from cold-hardiness and energy conservation during winter to one of dispersal, feeding and reproduction in summer beetles.     

High cold tolerance through four seasons and all free-living stages in an ectoparasite

Off-host stages of temperate parasites must cope with low temperatures. Cold tolerance is often highest in winter, as a result of diapause and cold acclimation, and low during the active summer stages. In some blood-feeding ectoparasites, offspring provisioning determines cold tolerance through all the non-feeding, off-host stages. Large size increases survival in the cold, but so far seasonal variation in within-female offspring size has not been associated with offspring cold tolerance. The deer ked (Lipoptena cervi) reproduces on cervids from autumn to spring. Newborn pupae drop off the host, facing frosts without any acclimation. We examined cold tolerance through 4 seasons and from birth to adulthood by means of short- and long-term frost exposure. We expected females to produce more tolerant offspring in winter than in spring. Large spring pupae survived prolonged frosts better than did small winter pupae. Thus more tolerant offspring were not produced when the temperature outside the host is at its lowest. Unexpectedly, the freezing points were -20 °C or below all year round. We showed that high cold tolerance is possible without acclimation regardless of life stage, which presumably correlates with other survival characteristics, such as the starvation resistance of free-living ectoparasites.     

Water relations of the freeze-tolerant New Zealand alpine cockroach Celatoblatta quinquemaculata (Dictyoptera: Blattidae)

Celatoblatta quinquemaculata is a freeze-tolerant alpine cockroach found on the Rock and Pillar Range, Central Otago, New Zealand. This study investigated seasonal changes in water content, as well as desiccation tolerance, and the relationship between desiccation and cold tolerance. Whole body water contents from field-fresh cockroaches collected over a 20 month period ranged from 69.9+/-1.0% fresh weight (FW) in February 1998 to 60.3+/-1.1% FW in July 1998. Water contents were significantly lower in winter than summer, and were positively correlated to microhabitat temperatures over the week preceding collection. Cockroaches survived the loss of up to 82% (mean: 56.7%+/-10.2) of their initial body water content, and the amount of water loss sustained was not dependent on the rate of water loss. Cockroaches did not suffer further mortality due to desiccation after removal to 99% relative humidity, but only regained lost water if given access to liquid water. Experimental dehydration did not enhance freeze-tolerance, but did slightly lower the supercooling point. It is concluded that reduction of body water content in winter may be a consequence of cold hardening responses, but desiccation does not constitute the cold hardening mechanism itself.     

Overwintering survival and spring emergence inMeligethes aeneus: Effects of body weight, crowding, and soil treatment withBeauveria bassiana

High overwintering mortality was recorded forMeligethes aeneus in the field in Finland, ranging from 85 to 98% depending on the source of the overwintering population. The main factor explaining, variation in survival was the body weight of the beetles in the autumn: only the heaviest beetles survived. Body weight, on the other hand, was influenced by treatment of the rape field soil withBeauveria bassiana, resulting in a 50% decrease in winter survival compared with the reference. The soil treatment did not appear to have direct mortality effects (pathogenesis) on the beetle neither in the summer nor in the winter, and there was no apparent effect on survival of crowding of the insects at the overwintering site. Density dependence in overwintering survival ofM. aeneus may function through the availability of pollen food in the autumn, and intraspecific competition for it. Treatment of the rape field soil withB. bassiana may be a feasible way to increase, the winter mortality and to lower the pollen beetle populations, but requires further research.     

Effects of starvation on body composition and cold tolerance in the collembolan Orchesella cincta and the isopod Porcellio scaber

The effects of long-term starvation on the body composition of the isopod Porcellio scaber (Latreille) and the collembolan Orchesella cincta (L.) were studied, by determining the body composition in starved and fed animals. A period under summer conditions (19 degrees C, 75% RH and L/D 16/8 photoperiod), was followed by a period under winter conditions (5 degrees C, 75% RH and LD 6/18 photoperiod). O. cincta was held under summer conditions for 3weeks, during which its protein and lipid content decreased, while its water content increased. In P. scaber, the same occurred during the 6weeks they were kept under summer conditions. During subsequent weeks under winter conditions, changes in cold tolerance of the animals were investigated. Cold tolerance and haemolymph osmolality were measured once a week. Starved animals had lower cold tolerance than fed ones. For P. scaber a decreased haemolymph osmolality was found in starved animals compared to fed ones. This is assumed to be caused by a combination of the consumption of carbohydrates out of the haemolymph and of protein reserves and the accumulation of body water. O. cincta appeared to be capable of osmoregulation, as haemolymph osmolality did not differ between starved and fed animals, despite differences in body water content. Decreased cold tolerance in starved animals of both species may be caused by increased water content or, more probably, by the decrease in reserves needed to produce cryoprotective substances.     

Overwintering physiology and microhabitat use of Phyllocnistis populiella (Lepidoptera: Gracilliariidae) in interior Alaska

We investigated the overwintering physiology and behavior of Phyllocnistis populiella Chambers, the aspen leaf miner, which has caused severe and widespread damage to aspen in Alaska over the past 10 yr. Active P. populiella moths caught in spring and summer supercooled to an average temperature of -16°C, whereas dormant moths excavated from hibernacula in the leaf litter during fall and winter supercooled to an average of -32°C. None of the moths survived freezing in the laboratory. Counts of overwintering moths in leaf litter across microhabitats in interior Alaska demonstrated that moths occurred at significantly higher density beneath white spruce trees than beneath the aspen host, several other hardwood species, or in open areas among trees. During winter, the temperature 1-2 cm below the surface of the leaf litter beneath white spruce trees was on average 7-9°C colder than beneath aspen trees, and we estimate that during at least one period of the winter the temperature under some white spruce trees may have been cold enough to cause mortality. However, the leaf litter under white spruce trees was significantly drier than the litter from other microhabitats, which may assist P. populiella moths to avoid inoculative freezing because of physical contact with ice. We conclude that in interior Alaska, P. populiella overwinter in a supercooled state within leaf litter mainly under nonhost trees, and may prefer relatively dry microhabitats over moister ones at the expense of lower environmental temperature.     

Low-temperature-induced changes in trehalose,mannitol and arabitol associated with enhanced tolerance to freezing in ectomycorrhizal basidiomycetes (<Emphasis Type="Italic">Hebeloma</Emphasis> spp.)

Ectomycorrhizal fungi have been shown to survive sub-zero temperatures in axenic culture and in the field. However, the physiological basis for resistance to freezing is poorly understood. In order to survive freezing, mycelia must synthesise compounds that protect the cells from frost damage, and certain fungal-specific soluble carbohydrates have been implicated in this role. Tissue concentrations of arabitol, mannitol and trehalose were measured in axenic cultures of eight Hebeloma strains of arctic and temperate origin grown at 22, 12, 6 and 2 degrees C. In a separate experiment, mycelia were frozen to -5 degrees C after pre-conditioning at either 2 degrees C or 22 degrees C. For some, especially temperate strains, there was a clear increase in specific soluble carbohydrates at lower growth temperatures. Trehalose and mannitol were present in all strains and the highest concentrations (close to 2.5% and 0.5% dry wt.) were recorded only after a cold period. Arabitol was found in four strains only when grown at low temperature. Cold pre-conditioning enhanced recovery of mycelia following freezing. In four out of eight strains, this was paralleled by increases in mannitol and trehalose concentration at low temperature that presumably contribute towards cryoprotection. The results are discussed in an ecological context with regard to mycelial overwintering in soil.     

Temporal and morphological factors related to mineral composition in Myriophyllum heterophyllum michx

The emergent floral stem, apex, sub-apex, mid-stem, lower stem, and roots of Myriophyllum heterophyllum Michx were analyzed for ash, P, Na, K, Ca, Mg, Fe, Mn, Zn, Cu and Pb. Samples were collected 14 times from June 1979 through July 1980 from Lake Winnipesaukee, New Hampshire, U.S.A.The plant segments sampled differed significantly in mineral content, but seasonal pulses for each mineral were usually in synchrony between the different segments sampled. Sodium (range, 0.8–2.7% dry wt.) and potassium (range, 1.4–3.3% dry wt.) were the dominant elements in the submersed stem. The dominant element in the floral spike was Ca (range, 2.4–4.1% dry wt.) and in the roots was Fe (range, 2.8–8.0% dry wt.). Sodium concentrations were greater in the submersed stem (range, 0.8–2.7% dry wt.), relative to the roots (range, 0.5–0.9% dry wt.) and flora stem (range, 0.3–1.1% dry wt.). Lead concentrated in the roots significantly more (range, 0.0040–0.0115% dry wt.), than in other plant parts (range, 0–0.0037% dry wt.).The submersed stem had spring or summer peaks in ash, P, Na, K, Ca, Mg, and Zn content, whereas Fe and Mn exhibited late winter to early spring peaks. No evidence of nutrient storage during the non-growing season was evident in the segments sampled. Explanations for the seasonal and morphological differences observed are presented.     

越冬期不同阶段二点委夜蛾越冬幼虫耐寒性变化

【目的】二点委夜蛾Athetis lepigone (Moschler)是我国夏玉米苗期的新害虫,随着耕作制度的改变,二点委夜蛾的发生危害区域和面积逐渐扩大。本研究探讨二点委夜蛾的抗寒能力,为揭示抗寒机理提供理论基础。【方法】分别在越冬期的3个不同阶段,即越冬初期（2012年11月7日）、越冬期（2012年1月20日）和越冬末期（2013年3月5日）,对二点委夜蛾老熟幼虫的体重、过冷却点（supercooling point, SCP）、结冰点（freezing point, FP）、含水量、脂肪和糖原含量进行测定。【结果】过冷却点在这3个时期有显著差异,最低值（-23.16±0.38℃）出现在1月份,最高值（-16.24±1.24℃）出现在越冬初期,结冰点变化趋势与过冷却点一致。通过定量检测发现,虫体鲜重与过冷却点无相关性（r=0.17, P=0.12）;脂肪含量在越冬初期含量最高,而在越冬末期最低;糖原含量在越冬期含量最低;自由水的含量随着过冷却能力升高而降低,随其降低而升高,而结合水含量恰好相反。【结论】二点委夜蛾的抗寒性在越冬期不同阶段出现明显的变化,即随着冬季低温的到来,其抗寒能力逐渐增强,冬季过后又随气温的回升,其抗寒力逐渐减弱。     

Adult feeding time, lipid accumulation, and overwintering in Aglais urticae and Inachis io (Lepidoptera: Nymphalidae)

The influence of restricted feeding time on the subsequent survival of adult Aglais urticae and Inachis io during diapause was tested in the laboratory. Abdominal lipid weight increased in the first 7 days of feeding by A. urticae and up to day 15 in I. io. Lipid as a proportion of dry weight also increased during this time. Individuals of both species feeding for 0–3 days began overwintering at significantly lower weights, and percentage weight loss during overwintering was more rapid than for those feeding for longer periods. Differences in fresh weights at the beginning of the overwintering period are reflected by differences in overwintering survival. In A. urticae , all 0–3 day feeders died in less than 150 days, in contrast, over 75% of 7–30 day feeders survived this period. In I. io , all 0–1 day feeders died within 160 days, less than 50% of 3 day feeders survived, whilst over 90% of7–15 day feeders were alive after this time. In I. io individuals feeding for one day, fresh weight is correlated with survival time suggesting that a larger body size may enhance survival time if feeding time is restricted.     

Study on the physiology of diapause, cold hardiness and supercooling point of overwintering pupae of the pistachio fruit hull borer, Arimania comaroffi

The pistachio fruit hull borer, Arimania comaroffi (Ragonot) (Lepidoptera: Pyralidae), is a key pest of pistachio orchards in Iran. This pest passes the winter as diapausing pupae. In this study, some physiological changes in relation to environmental temperature were investigated in field collected pupae. The relationship between supercooling point, cold hardiness and physiological changes of a wild population of this pest was also investigated. The glycogen content decreased with decrease in environmental temperature. Decrease in glycogen content was proportional to increase in total body sugar, trehalose, myo-inositol and sorbitol contents. In January with mean ambient temperature of 5.4°C, glycogen (5 mg/g fresh body weight) content was at the lowest level whereas total body sugar (10.3 mg/g fresh body weight), trehalose (8.6 mg/g fresh body weight), myo-inositol (5.3 mg/g fresh body weight) and sorbitol (2.6 mg/g fresh body weight) were at the highest levels. Total body sugar, trehalose, myo-inositol and sorbitol contents increased as mean temperature decreased from 22.7°C in October to 5.4°C in January. Total body lipid decreased during overwintering and reached to the lowest level at the end of March. Supercooling points were decreased from October to January and reached to the lowest level (-16°C) in January with minimum ambient temperature of -10°C. Survival at low temperature after 24 h was also greatest in January with 72% survival at -10°C, 39% survival at -15°C and 0% survival at -20°C. Increase in temperature from February onward, was proportional with increase in supercooling points and decrease in survival rate. Regardless of sampling date, all pupae died after 24 h at -20°C, whereas none pupae died after 24 h at -5°C. This indicates that this insect is freeze-intolerant.     

绿盲蝽越冬卵的耐寒能力

近年来,随着转基因棉花的大面积推广,绿盲蝽成为了我国棉花和果树生产的重要害虫。为了阐明绿盲蝽越冬生态适应性,研究了绿盲蝽卵在越冬过程中的耐寒力变化,测定了卵内生化物质的含量,结果表明:绿盲蝽越冬卵低温存活力呈现出明显的月份变化,在-10℃、-20℃处理下,绿盲蝽的越冬卵的半致死时间从大到小的顺序依次为:1月>2月>12月>3月>4月,在-30℃处理下从大到小的顺序依次为:1月>12月>3月>2月>4月。在极端低温(-20℃)下1、2、3、4和5 d后,4月份保护卵死亡率明显低于相同处理下的4月份裸露卵的死亡率,枣枝中的越冬卵死亡率分别为4.32%、5.36%、5.42%、6.79%和7.63%,剥离出来的越冬卵死亡率分别为46.06%、51.84%、54.59%、63.07%和74.41%。人工滞育卵的耐寒性强于正常发育卵的耐寒性,弱于自然越冬过程中滞育卵的耐寒性。冷驯化可以显著提高绿盲蝽越冬卵的低温存活力,在0℃冷驯化20 min后,越冬卵的低温(-20℃、100 h)死亡率显著降低,冷驯化40 min后,低温死亡率趋于平稳,均在37%左右。越冬卵体内物质呈明显的季节性变化,越冬卵越冬期的含水量显著高于越冬后,其中1月份最高(43.98%),4月份达到最低(38.79%)。越冬卵体内总脂肪含量在整个越冬过程中逐渐降低,从12月份的38.24%,降低到4月份的27.08%。蛋白质和糖的含量均是先降低后升高,其中蛋白质从12月份的78.77μg/mg,降低到1月份的59.80μg/mg,然后又逐渐升高至4月份的73.62μg/mg,体内总糖含量由12月份的39.60μg/mg降低至1月份的21.17μg/mg,然后又逐渐升高至4月份的35.10μg/mg。绿盲蝽越冬卵的耐寒力随着月份的变化而变化,在整个越冬期间表现出较强的抗寒性,能够抵御冬季低温,而其越冬场所的保护作用增加了其对于冬季严寒的适应性。