Effects of alcohol and coca on foot temperature responses of highland Peruvians during a localized cold exposure

Two groups of highland Quechua Indian males were tested under conditions of local foot exposure to cold air (0°C). Foot temperatures were monitored throughout the hour cold test and for 16 minutes recovery at room temperature (24°C). In the first group (age range 14–20 years), 29 subjects were tested while chewing coca leaves and while under control conditions. The second group (age range 20–50 years) of 25 subjects was tested while consuming 1.1 gm of ethyl alcohol per kilogram of body weight and again under control conditions. Both drugs (coca and alcohol) are habitually consumed by members of the native population. The mastication of coca leaves had no effect on foot skin temperatures. Alcohol consumption, however, elevated foot temperatures to between 4 and 6°C higher than control values at the end of 60 minutes of cold exposure. It is suggested that alcohol consumption gives the Indian a slight thermal advantage and increases levels of comfort during natural cold exposure.     

Molecular cloning and functional characterization of the dopamine transporter from Eloria noyesi, a caterpillar pest of cocaine-rich coca plants

Cocaine is produced by coca plants as a chemical defense to deter feeding by insects. It has been shown that cocaine sprayed on tomato leaves reduces insect feeding, causes abnormal behaviors at low doses and kills feeding insects at doses equivalent to that in coca leaves [Nathanson, J.A., Hunnicutt, E.J., Kantham, L., Scavone, C., 1993. Cocaine as a naturally occurring insecticide. Proc. Natl. Acad. Sci. U. S. A. 90, 9645-9648.]. Most insects avoid coca leaves except the larvae of Eloria noyesi, a caterpillar pest of coca plants, which feeds preferentially on coca leaves. In the current study, we cloned and characterized the dopamine transporters (DATs) from caterpillars of E. noyesi (enDAT) and the silkworm, Bombyx mori (B. mori, bmDAT). The two insect DATs shared 88% amino acid sequence homology and functional similarity. Although enDAT and bmDAT showed the highest affinity for dopamine among endogenous amines, they were more sensitive to mammalian NET-selective inhibitors than to mammalian DAT-selective inhibitors. Despite a high cocaine content in the food source for E. noyesi, cocaine sensitivity of enDAT was similar to that of bmDAT, suggesting that mechanisms other than DAT insensitivity to cocaine, such as cocaine sequestration, might be responsible for cocaine resistance in this species. Given the significant differences in pharmacological profile from mammalian DATs, invertebrate DATs provide excellent tools for identifying regions and residues in the transporters that contribute to high-affinity binding of psychostimulants and antidepressants.     

Storage effects on genomic DNA in rolled and mature coca leaves

Rolled and mature leaf tissue was harvested from Erythroxylum coca var. coca Lam. (coca) to determine a method for storage that would maintain DNA with high quality and content up to 50 days. Harvesting coca leaf tissue under Andean field conditions often requires storage from 3 to 10 days before extraction where tissue integrity is lost. All samples of rolled and mature coca leaf tissue were harvested and separately stored fresh in RNAlater for 50 days at 4 degrees, -20 degrees, and 23 degrees C, while similar samples were air-dried for 72 h at 23 degrees C or oven-dried for 72 h at 40 degrees C after storage, before extraction. Triplicate samples of each tissue type were extracted for DNA at 10-day intervals and showed that DNA integrity and content were preserved in leaf tissue stored at 4 degrees and -20 degrees C for 50 days. Rolled and mature leaf tissue stored at 4 degrees, -20 degrees, and 23 degrees C showed insignificant degradation of DNA after 10 days, and by day 50, only leaf tissue stored at 4 degrees and -20 degrees C had not significantly degraded. All air- and oven-dried leaf tissue extracts showed degradation upon drying (day 0) and continuous degradation up to day 50, despite storage conditions. Amplified fragment length polymorphism analysis of DNA from rolled and mature leaf tissue of coca stored at 4 degrees and -20 degrees C for 0, 10, and 50 days showed that DNA integrity and content were preserved. We recommend that freshly harvested rolled or mature coca leaf tissue be stored at 4 degrees, -20 degrees, and 23 degrees C for 10 days after harvest, and if a longer storage is required, then store at 4 degrees or -20 degrees C.     

Identification of Erythroxylum taxa by AFLP DNA analysis

Erythroxylum coca, indigenous to the Andean region of South America, is grown historically as a source of homeopathic medicine. However, in the last century, cultivation of E. coca and several closely-related species for the production of illicit cocaine has become a major global problem. Two subspecies, E. coca var. coca and E. coca var. ipadu, are almost indistinguishable phenotypically; a related cocaine-bearing species also has two subspecies (E. novogranatense var. novogranatense and E. novogranatense var. truxillense) that are phenotypically similar, but morphologically distinguishable. The purpose of this research was to discover unique AFLP DNA patterns ("genetic fingerprinting") that characterize the four taxa and then, if successful, to evaluate this approach for positive identification of the various species of coca. Of seven different AFLP primer pairs tested, a combination of five proved optimal in differentiating the four taxa as well as a non-cocaine-bearing species, E. aerolatum. This method of DNA fragment separation was selective, and faster, for coca identification, compared with analyses based on flavonoid chemotaxonomy. Using the 5-primer AFLP approach, 132 known and unknown coca leaf accessions were evaluated. Of these, 38 were collected in 1997-2001 from illicit coca fields in Colombia, and all were genetically differentiated from coca originating in Peru and Bolivia. Based on the DNA profiling, we believe that the Colombian coca now represents a hybridization of E. coca var. ipadu. Geographical profiling within Colombia also seems feasible as new coca production areas are developed or new types of coca are introduced within traditional growing areas.     

The effect of repeated mild cold water immersions on the adaptation of the vasomotor responses

There are several types of cold adaptation based on the alteration of thermoregulatory response. It has been thought that the temperature of repeated cold exposures during the adaptation period is one of the factors affecting the type of cold adaptation developed. This study tested the hypothesis that repeated mild cold immersions would induce an insulative cold adaptation but would not alter the metabolic response. Seven healthy male participants were immersed to their xiphoid process level repeatedly in 26°C water for 60 min, 3 days every week, for 4 weeks. During the first and last exposure of this cold acclimation period, the participants underwent body immersion tests measuring their thermoregulatory responses to cold. Separately, they conducted finger immersion into 5°C water for 30 min to assess their cold-induced vasodilation (CIVD) response before and after cold acclimation. During the immersion to xiphoid process, participants showed significantly lower mean skin temperature and skin blood flow in the forearm post-acclimation, while no adaptation was observed in the metabolic response. Additionally, blunted CIVD responses were observed after cold acclimation. From these results, it was considered that the participants showed an insulative-type of cold acclimation after the repeated mild cold immersions. The major finding of this study was the acceptance of the hypothesis that repeated mild cold immersion was sufficient to induce insulative cold adaptation but did not alter the metabolic response. It is suggested that the adaptation in the thermoregulatory response is specific to the response which is repeatedly stimulated during the adaptation process.     

Archaeological evidence of coca (Erythroxylum coca,erythroxylaceae) in the upper mantaro valley,Peru

Prehistoric remains of coca (Erythroxylum spp.) are rarely uncovered by archaeologists or positively identified by botanists because of their fragile nature and the lack of rigorous archaeological collection techniques. This absence of plant evidence has made evolutionary studies of diffusion and use of coca difficult. From special depositional conditions in the Mantaro area of central Peru, one coca leaf and two endocarps have been uncovered and identified as Erythroxylum coca var. coca. These three specimens came from elite-status contexts dating to the Late Intermediate and the Late Horizon-Early Colonial Periods. These remains provide the first highland evidence for access to coca-producing, ceja de montaña farms, which lie more than 50 km away on the eastern slope of the Andes.     

Inter- and intra-specific variation among five Erythroxylum taxa assessed by AFLP

BACKGROUND: and Aims The four cultivated Erythroxylum taxa (E. coca var. coca, E. novogranatense var. novogranatense, E. coca var. ipadu and E. novogranatense var. truxillense) are indigenous to the Andean region of South America and have been cultivated for folk-medicine and, within the last century, for illicit cocaine production. The objective of this research was to assess the structure of genetic diversity within and among the four cultivated alkaloid-bearing taxa of Erythroxylum in the living collection at Beltsville Agricultural Research Center. METHODS: Amplified fragment length polymorphism (AFLP) fingerprinting was performed in 86 Erythroxylum accessions using a capillary genotyping system. Cluster analysis, multidimensional scaling (MDS) and analysis of molecular variance (AMOVA) were used to assess the pattern and level of genetic variation among and within the taxa. KEY RESULTS: A clear distinction was revealed between E. coca and E. novogranatense. At the intra-specific level, significant differentiation was observed between E. c. var. coca and E. c. var. ipadu, but the differentiation between E. n. var. novogranatense and E. n. var. truxillense was negligible. Erythroxylum c. var. ipadu had a significantly lower amount of diversity than the E. c. var. coca and is genetically different from the E. c. var. ipadu currently under cultivation in Colombia, South America. CONCLUSIONS: There is a heterogeneous genetic structure among the cultivated Erythroxylum taxa where E. coca and E. novogranatense are two independent species. Erythroxylum coca var. coca is most likely the ancestral taxon of E. c. var. ipadu and a founder effect may have occurred as E. c. var. ipadu moved from the eastern Andes in Peru and Bolivia into the lowland Amazonian basin. There is an indication of artificial hybridization in coca grown in Colombia.     

Coca chewing for exercise: hormonal and metabolic responses of nonhabitual chewers

Favier, Roland, Esperanza Caceres, Laurent Guillon, BrigitteSempore, Michel Sauvain, Harry Koubi, and Hilde Spielvogel. Cocachewing for exercise: hormonal and metabolic responses of nonhabitualchewers. J. Appl. Physiol. 81(5):1901-1907, 1996.To determine the effects of acute coca use onthe hormonal and metabolic responses to exercise, 12 healthynonhabitual coca users were submitted twice to steady-state exercise(~75% maximal O₂ uptake). Onone occasion, they were asked to chew 15 g of coca leaves 1 h beforeexercise, whereas on the other occasion, exercise was performed after 1 h of chewing a sugar-free chewing gum. Plasma epinephrine,norepinephrine, insulin, glucagon, and metabolites (glucose, lactate,glycerol, and free fatty acids) were determined at rest before andafter coca chewing and during the 5th, 15th, 30th, and 60th min ofexercise. Simultaneously to these determinations, cardiorespiratoryvariables (heart rate, mean arterial blood pressure, oxygen uptake, andrespiratory gas exchange ratio) were also measured. At rest, cocachewing had no effect on plasma hormonal and metabolic levels exceptfor a significantly reduced insulin concentration. During exercise, theoxygen uptake, heart rate, and respiratory gas exchange ratio weresignificantly increased in the coca-chewing trial compared with thecontrol (gum-chewing) test. The exercise-induced drop in plasma glucoseand insulin was prevented by prior coca chewing. These results contrastwith previous data obtained in chronic coca users who display duringprolonged submaximal exercise an exaggerated plasma sympatheticresponse, an enhanced availability and utilization of fat (R. Favier,E. Caceres, H. Koubi, B. Sempore, M. Sauvain, and H. Spielvogel.J. Appl. Physiol. 80: 650-655, 1996). We conclude that, whereas coca chewing might affect glucose homeostasis during exercise, none of the physiological data provided bythis study would suggest that acute coca chewing in nonhabitual userscould enhance tolerance to exercise.

     

Flavonoids as chemotaxonomic markers for Erythroxylum australe

Methanolic leaf extracts of Erythroxylum australe F. Muell. produced eight O-conjugated flavonoids. Six of the flavonoid aglycones were dihydroisoflavones (all dihydro-orobol derivatives), one a flavanone, eriodictyol, and one a flavonol, quercetin. The major glycosides of the flavonoids included mono-glucosyl-rhamnosyls and dirhamnosyl-glucosides with either 3, 5, 7 or 3', 4' linkage or a combination thereof The array of flavonoids present in E. australe suggests kinship to E. ulei and linkage to the four cultivated alkaloid-bearing Erythroxylum, especially the ancestral E. coca var. coca. Because of the uniqueness of the flavonoids present in leaf tissue of E. australe they are unambiguously useful as chemotaxonomic markers for the taxon.     

Coca chewing in prehistoric coastal Peru: dental evidence

In this study, we describe the dental health of four prehistoric human populations from the southern coast of Peru, an area in which independent archaeological evidence suggests that the practice of coca-leaf chewing was relatively common. A repeated pattern of cervical-root caries accompanying root exposure was found on the buccal surfaces of the posterior dentition, coinciding with the typical placement of coca quids during mastication. To further examine the association between caries patterning and coca chewing, caries site characteristics of molar teeth were utilized as indicators for estimating the likelihood of coca chewing for adults within each of the study samples. Likelihood estimates were then compared with results of a test for coca use derived from hair samples from the same individuals. The hair and dental studies exhibited an 85.7% agreement. Thus, we have demonstrated the validity of a hard-tissue technique for identifying the presence of habitual coca-leaf chewing in ancient human remains, which is useful in archaeological contexts where hair is not preserved. These data can be used to explore the distribution of coca chewing in prehistoric times. Simultaneously, we document the dental health associated with this traditional Andean cultural practice.     

Body fluid homeostasis and cardiovascular adjustments during submaximal exercise: influence of chewing coca leaves

 The present study was undertaken to determine the haematological and cardiovascular status, at rest and during prolonged (1 h) submaximal exercise (approximately 70% of peak oxygen uptake) in a group (n = 12) of chronic coca users after chewing approximately 50 g of coca leaves. The results were compared to those obtained in a group (n = 12) of nonchewers. At rest, coca chewing was accompanied by a significant increase in heart rate [from 60 (SEM 4) TO 76 (SEM 3) beats · min⁻¹], in haematocrit [from 53.2 (SEM 1.2) to 55.6 (SEM 1.1)%] in haemoglobin concentration, and plasma noradrenaline concentration [from 2.8 (SEM 0.4) to 5.0 (SEM 0.5) μmol · l⁻¹]. It was calculated that coca chewing for 1 h resulted in a significant decrease in blood [−4.3 (SEM 2.2)%] and plasma [−8.7 (SEM 1.2)%] volume. During submaximal exercise, coca chewers displayed a significantly higher heart rate and mean arterial blood pressure. The exercise-induced haemoconcentration was blunted in coca chewers compared to nonchewers. It was concluded that the coca-induced fluid shift observed at rest in these coca chewers was not cumulative with that of exercise, and that the hypovolaemia induced by coca chewing at rest compromised circulatory adjustments during exercise. Accepted: 29 October 1996     

Context‐dependent effects of cold stress on behavioral,physiological, and life‐history traits of the red flour beetle

Animals are exposed in nature to a variety of stressors. While stress is generally harmful, mild stress can also be beneficial and contribute to reproduction and survival. We studied the effect of five cold shock events versus a single cold shock and a control group, representing three levels of stress (harsh, mild, and no stress), on behavioral, physiological, and life‐history traits of the red flour beetle (Tribolium castaneum, Herbst 1797). Beetles exposed to harsh cold stress were less active than a control group: they moved less and failed more frequently to detect a food patch. Their probability to mate was also lower. Beetle pairs exposed to harsh cold stress frequently failed to reproduce at all, and if reproducing, females laid fewer eggs, which were, as larvae in mid‐development, smaller than those in the control group. However, harsh cold stress led to improved female starvation tolerance, probably due to enhanced lipid accumulation. Harsh cold shock also improved tolerance to an additional cold shock compared to the control. Finally, a single cold shock event negatively affected fewer measured response variables than the harsh cold stress, but also enhanced neither starvation tolerance nor tolerance to an additional cold shock. The consequences of a harsher cold stress are thus not solely detrimental but might even enhance survival under stressful conditions. Under benign conditions, nevertheless, harsh stress impedes beetle performance. The harsh stress probably shifted the balance point of the survival‐reproduction trade‐off, a shift that did not take place following exposure to mild stress.     

An Alginate Prill Formulation of Fusarium oxysporum Schlechtend: Fr. f. sp. erythroxyli for Biocontrol of Erythroxylum coca var. coca

A rice alginate prill formulation of isolate EN - 4 of Fusarium oxysporum f . sp . erythroxyli, pathogenic to Erythroxylum coca var . coca (coca) , was evaluated in greenhouse and field studies for its ability to enhance pathogen populations in the soil and cause disease in coca . The formulation was applied to four different soil types in the greenhouse at 33 . 6 kg ha 1 . It enhanced the population of EN - 4 in each soil and most ( > 90%) of the fungal population remained in the upper 5 cm of soil during the 49 - day experiment . When applied in field experiments , the formulation enhanced the population of EN - 4 in the soil . Isolate EN - 4 was present in the upper 7 . 6 cm of soil 28 days after application at populations similar to those in the greenhouse studies (1 103 to 1 104 colony - forming units (CFUs) / g of soil) . Elevated populations of the pathogen (1 102 CFUs / g of soil) were still present in treated soils 229 days after application of the formulation . The areas used for field studies were already infested with the pathogen and typically developed high levels of fusarium wilt within 2 years of planting with coca . The formulated F. oxysporum began having a significant effect on plant death 100 - 200 days after application based on repeated measures analysis . These data suggest that a formulation of F. oxysporum f . sp . erythroxyli which enhances the incidence of fusarium wilt in coca fields can be produced using established techniques .     

华南地区龙眼寒害灾损风险评估

基于华南地区64个基本气象站1961—2012年逐日气象资料,采用公认的龙眼寒害灾害指标,结合农业气象灾害风险研究的方法与模拟技术,并考虑龙眼寒害灾损减产风险在不同生育期（花芽生理期、花芽形态分化期、休眠期）之间的差别,对1961—2012年华南地区龙眼不同发育时段的寒害灾损最大风险进行定量评估与分析.结果表明： 在花芽生理期,各地区龙眼受灾最严重的是轻度寒害,其次为重度寒害,最后为中度寒害;不同寒害致灾等级对各地龙眼造成的危害程度不同,在轻度寒害威胁下,龙眼受灾轻重次序为福建、广东和海南、广西,中度寒害威胁下,龙眼受灾轻重次序为海南、广东和广西、福建,重度寒害威胁下,龙眼受灾轻重次序为海南、广东和广西、福建.在花芽形态分化期,各地区龙眼受灾最严重的是轻度寒害,其次为重度寒害,最后为中度寒害;该时段内不同寒害致灾等级对各地龙眼造成的危害程度相似,龙眼受灾轻重次序均为海南、广东和广西、福建.在休眠期,各地区龙眼寒害受灾最严重的是轻度寒害,其次为重度寒害,最后为中度寒害;该时段内不同寒害致灾等级对各地龙眼造成的危害程度不完全相同,轻度和重度寒害威胁下,各地龙眼受灾轻重次序为海南、广东和广西、福建,中度寒害威胁下,海南和广西龙眼受灾最轻,其次为广东,福建受灾最严重.同一寒害致灾等级下,不同发育时段龙眼寒害灾损减产最大风险指数差异显著：轻度寒害威胁下,各地区龙眼在花芽生理期受到危害最重,其次为花芽形态分化期,休眠期危害最轻;中度和重度寒害威胁下,各地区龙眼在花芽生理期受到危害最重,其次为休眠期,花芽形态分化期危害最轻.     

Effects of Mild Chronic Intermittent Cold Exposure on Rat Organs

Cold adaptation is a body''s protective response to cold stress. Mild chronic intermittent cold (CIC) exposure has been used to generate animal models for cold adaptation studies. However, the effects of mild CIC exposure on vital organs are not completely characterized. In the present study, we exposed rats to mild CIC for two weeks, and then measured the body weights, the weights of brown adipose tissue (BAT), the levels of ATP and reactive oxygen species (ROS) in the brains, livers, hearts, muscles and BATs. Rats formed cold adaptation after exposure to CIC for two weeks. Compared to rats of the control group that were hosted under ambient temperature, rats exposed to mild CIC showed a lower average body weight, but a higher weight of brown adipose tissue (BAT). Rats exposed to CIC for two weeks also exhibited higher levels of ATP and ROS in all examined organs as compared to those of the control group. In addition, we determined the expression levels of cold-inducible RNA binding protein (Cirbp) and thioredoxin (TRX) in rat tissues after 2 weeks of CIC exposure. Both Cirbp and TRX were increased, suggesting a role of these two proteins for establishment of cold adaptation. Together, this study reveals the effects of mild CIC exposure on vital organs of rats during CIC exposure.     

The identification of coca (Erythroxylutn species): 1860–1910

The taxonomic history of plants known under the name 'coca' is complex. During the period 1860–1910, botanists, horticulturalists and pharmacists became increasingly interested in the varieties of coca then known in cultivation. A debate over the correct identity of the cultivated cocas ensued which continues today. During the latter part of the 19th century and early part of the 20th century, several new taxa were described from cultivation which significantly -complicated the taxonomy. Notable contributors were D. Morris in Kew, W. Burck in Bogor, H. H. Rusby in New York and O. E. Schulz in Berlin. In order to evaluate the complex interaction among these workers, it is necessary to examine the problem chronologically. Two cultivated species of commercial coca are now recognized: Erythroxylutn coca Lam. and Erythroxylutn nooogranatense (Morris) Hieron., each of which has one distinct variety in cultivation: E. coca var. ipadu Plowman and E. novogranatense var. truxillense (Rusby) Plowman, respectively.     

Coca Leaf Use in Southern Peru: Some Biosocial Aspects

The use of coca leaves in the Andean region has usually been condemned as a simple addiction to cocaine. This paper summarizes a series of studies in the southern Andes which consider the biological and economic motivations of the users. It is suggested that consumption of leaves is limited to avoid the undesirable effects of large doses of cocaine, while the smaller doses received are beneficial in certain aspects of the arduous life at high altitude. The persistence of the practice is viewed in terms of economics. It is concluded that coca plays a role in Andean life which is not related to simple addictive properties .     

Can lacewings feed on pests in winter? (Neur.: Chrysopidae and hemerobiidae)

Some lacewings occur in winter as larvae and may be efficient predators, either under Mediterranean and mild temperate climates, or in cold greenhouses. They can be used to help controlling aphids in winter. Among chrysopids,Dichochrysa spp. overwinter as second and/or third instars; they show a low preying rate, both a moderate cold hardiness and a minimal activity threshold.Nineta pallida overwinters as first instars which have a very low activity threshold and a high cold hardiness. In hemerobiids — namely various spp. ofHemerobius, Wesmaelius, Micromus — hibernating larvae manifest prey searching and feeding activity at low temperatures. Minimal thermal thresholds may be very low in embryos and in larvae. Adults often are insensitive to photoperiod and so do not exhibit any diapause under short daylength conditions; they have a low minimal activity threshold for preying and reproducing.     

Regional differences in temperature sensation and thermal comfort in humans

Sensations evoked by thermal stimulation (temperature-related sensations) can be divided into two categories, "temperature sensation" and "thermal comfort." Although several studies have investigated regional differences in temperature sensation, less is known about the sensitivity differences in thermal comfort for the various body regions. In the present study, we examined regional differences in temperature-related sensations with special attention to thermal comfort. Healthy male subjects sitting in an environment of mild heat or cold were locally cooled or warmed with water-perfused stimulators. Areas stimulated were the face, chest, abdomen, and thigh. Temperature sensation and thermal comfort of the stimulated areas were reported by the subjects, as was whole body thermal comfort. During mild heat exposure, facial cooling was most comfortable and facial warming was most uncomfortable. On the other hand, during mild cold exposure, neither warming nor cooling of the face had a major effect. The chest and abdomen had characteristics opposite to those of the face. Local warming of the chest and abdomen did produce a strong comfort sensation during whole body cold exposure. The thermal comfort seen in this study suggests that if given the chance, humans would preferentially cool the head in the heat, and they would maintain the warmth of the trunk areas in the cold. The qualitative differences seen in thermal comfort for the various areas cannot be explained solely by the density or properties of the peripheral thermal receptors and thus must reflect processing mechanisms in the central nervous system.     

Effects of Starvation and Thermal Stress on the Thermal Tolerance of Silkworm, <Emphasis Type="Italic">Bombyx mori:</Emphasis> Existence of Trade-offs and Cross-Tolerances

Organisms, in nature, are often subjected to multiple stressors, both biotic and abiotic. Temperature and starvation are among the main stressors experienced by organisms in their developmental cycle and the responses to these stressors may share signaling pathways, which affects the way these responses are manifested. Temperature is a major factor governing the performance of ectothermic organisms in ecosystems worldwide and, therefore, the thermal tolerance is a central issue in the thermobiology of these organisms. Here, we investigated the effects of starvation as well as mild heat and cold shocks on the thermal tolerance of the larvae of silkworm, Bombyx mori (Linnaeus). Starvation acted as a meaningful or positive stressor as it improved cold tolerance, measured as chill coma recovery time (CCRT), but, at the same time, it acted as a negative stressor and impaired the heat tolerance, measured as heat knockdown time (HKT). In the case of heat tolerance, starvation negated the positive effects of both mild cold as well as mild heat shocks and thus indicated the existence of trade-off between these stressors. Both mild heat and cold shocks improved the thermal tolerance, but the effects were more prominent when the indices were measured in response to a stressor of same type, i.e., a mild cold shock improved the cold tolerance more than the heat tolerance and vice versa. This improvement in thermal tolerance by both mild heat as well as cold shocks indicated the possibility of cross-tolerance between these stressors.