Metabolic Basis for Injury to Plants from Combinations of O(3) and SO(2): Studies with Modifiers of Pollutant Toxicity

Pisum sativum L. cv Alsweet (garden pea) and Lycopersicon esculentum Mill. flacca (mutant tomato) were chosen to evaluate the metabolic basis for plant injury from combinations of O₃ + SO₂. The plants were exposed under conditions reported to specifically alter O₃ or SO₂ toxicity; light versus dark exposures, and treatment with the fungal metabolite fusicoccin (FC), the O₃ injury inhibitor N-[2-(2-oxo-1-imidazolidiny) ethyl]-N′-phenylurea (EDU), and the SO₂ injury stimulator diethyldithiocarbamate (DDTC). Plants were grown in controlled environment chambers and exposed to combinations of O₃ (0.05-0.2 microliters per liter) and SO₂ (0.1-0.3 microliters per liter) for 2 hours. Peas treated with FC had the same or greater injury (quantified by visual rating) with O₃ + SO₂ exposures compared to plants not treated with FC. For plants with open stomata in the dark as well as light, i.e. FC-treated peas and tomatoes, there was no change or an increase in foliar necrosis with O₃ + SO₂ exposures in the dark versus light. Peas treated with EDU had an almost complete absence of O₃ injury, no change in SO₂ injury, and moderate decreases in injury from combinations of O₃ + SO₂ compared to plants not treated with EDU. Tomatoes treated with DDTC showed the same or less injury compared to plants not treated with DDTC and exposed to O₃ or SO₂. The plant responses to the experimental treatments and O₃ + SO₂ resembled O₃ responses more than SO₂ responses. The evidence for O₃-like responses are: no change or increase in injury in the light versus dark, and EDU-induced decreases in injury. Evidences for SO₂-like responses are: incomplete protection from injury with EDU, and no change or increased injury to FC-treated versus untreated plants. Thus, a metabolic mechanism affected by both pollutants may be associated with the combination injury, e.g. effects the plasma membrane.     

First Record of <Emphasis Type="Italic">Euphoria lurida</Emphasis> Fabricius (Coleoptera: Scarabaeidae) Injurious to Safflower (<Emphasis Type="Italic">Carthamus tinctorius</Emphasis> L.) (Asterales: Asteraceae) in Brazil

We present the first report on Euphoria lurida (Fabricius) (Coleoptera: Scarabaeidae) infestation on safflower (Carthamus tinctorius L.), a crop of industrial and medicinal importance. Between September and October 2013–2015 in Paraná State, we observed E. lurida adults feeding on safflower plants from the inception of flower head formation onwards, over an area of approximately 400 m². Losses in the productivity of infested plants were estimated between 15 and 50%. The damage was characterized by perforations in the upper portion and at the base of the developing flower heads or open flowers, resulting in withering and abortion of the reproductive structures.     

Diapause Induction and Termination in Hyphantria cunea (Drury) (Lepidoptera: Arctiinae)

The fall webworm, Hyphantria cunea (Drury), enters facultative diapause as a pupa in response to short-day conditions during autumn. Photoperiodic response curves showed that the critical day length for diapause induction was 14 h 30 min, 14 h 25 min and 13 h 30 min at 22, 25 and 28°C, respectively. The photoperiodic responses under non-24 h light–dark cycles demonstrated that night length played an essential role in the determination of diapause. Experiments using a short day length interrupted by a 1-h light pulse exhibited two troughs of diapause inhibition and the effect of diapause inhibition was greater in the early scotophase than in the late scotophase. The diapause-inducing short day lengths of 8, 10 and 12 h evoked greater intensities of diapause than did 13 and 14 h. Diapause can be terminated without exposure to chilling, but chilling at 5°C for 90 and 120 d significantly accelerated diapause development, reduced mortality, and synchronized adult emergence. Additionally, the potential for H. cunea from the temperate region (Qingdao) to emerge and overwinter under field conditions in subtropical regions (Nanchang) of China was evaluated. Pupae that were transferred to Nanchang in early July showed a 60% survival rate and extremely dispersed pupal period (from 12 to 82 days), suggesting that some pupae may undergo summer diapause. Diapausing temperate region pupae that were moved out-of-doors in Nanchang during October showed approximately 20% overwintering survival; moreover, those pupae that overwintered successfully emerged the next spring during a period when their host plants would be available. The results indicate that this moth has the potential to expand its range into subtropical regions of China.     

The subgenus Persicargas (Ixodoidea: Argasidae: Argas). 25. Effect of temperature on diapause termination in female A. (P.) arboreus Kaiser,Hoogstraal and Kohls

The effect of constant 26, 30, 34, and 37 C temperatures on diapause incidence (percentage of diapause females) and intensity (duration of preoviposition period) was compared in field-collected (FC) and laboratory-reared (LR) F₁ and F₂ female A. (P.) arboreus. Diapause incidence, 89–100%, and intensity 115–133 days, in the FC were high at all temperatures except at 30 C when the intensity was reduced (84 days). Diapause incidence, 91–94%, and intensity, 132–137 days, in LRF₁ were high at 26 and 30 C. At 34 and 37 C, both (33% and 78 days) were lower than in FC and LRF₁ at 26 and 30 C. Diapause incidence was always lower in LRF₂ than in FC and LRF₁ and decreased as the temperature increased (58, 30, 17, and 0%, respectively). Diapause intensity in LRF₂ at 26 C (133 days) was high and similar to that in FC and LRF₁ at 26 C but was low at 30 and 34 C (84 and 87 days, respectively). In all groups, diapause intensity was higher in females kept outdoors (191–218 days) than in those held in the laboratory. The results suggest that rearing in the laboratory caused an increased sensitivity of diapause LRF₁ and F₂ females to high temperature.     

Spatio-temporal dynamics of <Emphasis Type="Italic">Scotinophara lurida</Emphasis> (Hemiptera: Pentatomidae) in rice fields

Studying the spatial pattern of insect pests and the temporal stability of their patterns is important in understanding underlying ecological mechanisms and in developing pest management programs in cultivated crop systems. To elucidate the spatio-temporal pattern of the black rice bug, Scotinophara lurida, in rice fields, samplings were conducted in two rice fields over 2 years. Using spatial analysis by distance indices, the spatial pattern of each developmental stage of S. lurida and their temporal stability of the spatial pattern were identified. Most of the I _a (the index of aggregation) values for overwintered adults and eggs of S. lurda were close to 1, indicating random distribution pattern while nymphs and new adults mainly had I _a values >1, indicating an aggregated distribution pattern. According to spatial association analysis between successive samples using X (the index of spatial association), the spatial pattern of S. lurida showed strong temporal stability throughout the season. Also, there was strong association between the spatial patterns of developmental stages, indicating the great effect of the spatial pattern of the previous developmental stage on that of later developmental stage. Factors influencing the spatial pattern and spatial stability of S. lurida are discussed.     

Seasonal patterns of the thermal response in relation to sugar and polyol accumulation in overwintering adults of elm leaf beetle, Xanthogaleruca luteola (Coleoptera: Chrysomelidae)

Elm leaf beetle, Xanthogaleruca luteola (Muller), is one of the key pests of elm trees that survive winter in reproductive diapause in sheltered locations. Overwintering adults of the elm leaf beetle showed a complex sugar/polyol cryoprotectant system. The major components of the multiple systems were glucose, myo-inositol and trehalose. In this study, we investigated the seasonal profile of low molecular weight compounds and glycogen in natural population and also in response to thermal constant regimes (5 and 15 °C). Among these components, a remarkable seasonal pattern of accumulation/depletion was observed in myo-inositol over the course of hibernation with the development of diapause progress. Incubating at 5 °C only elicited a strong response in myo-inositol synthesis during diapause. It suggests that the elm leaf beetle accumulates myo-inositol not only in relation to entering diapause but also in response to low temperatures and their interactions. The laboratory acclimation experiments showed that adults exposed to 15 °C had no chance for accumulation of low molecular weight carbohydrate even during diapause. The results of this study illustrated that overwintering adults of elm leaf beetle produce myo-inositol as the primary substance which plays a specific role in some biochemical adjustments in overwintering adults of X. luteola.     

Enhancing bio-suppression of Parthenium hysterophorus L.: Diapause in Zygogramma bicolorata Pallister and its manipulation through insulin-like peptides (ILPs)

In-depth investigations on diapause behaviour of Z. bicolorata revealed that the adults entered diapause at any time from August to December and that the number peaked (42.00%) during the last half of November. The percentage of adults entering diapause increased with a decrease in day length. Weight of diapausing adults was significantly higher than weight of non-diapausing adults. The percentage of adults undergoing diapause at 30 °C was significantly lower than those undergoing diapause at 15 and 25 °C. The percentage of adults burrowing increased with increasing moisture. In silty soil and soil with high organic matter, 46.7% and 49.2% of adults entered diapause, respectively, whereas in sandy soil, only 23.5% of adults entered diapause. When newly emerged beetles were exposed to 5 μg of human insulin 30/70, a significantly lower percentage of treated adults underwent diapause compared to untreated adults under both feeding and no feeding conditions. Insulin treatment also influenced the emergence period from diapause (93.92 ± 1.73 days), percent emergence (81 ± 1.54%) and fecundity/month (512.7 ± 25.38 eggs) of Z. bicolorata in treated adults as compared to untreated adults (109.05 ± 2.2, 74.00 ± 1.82 and 438.3 ± 19.33 eggs, respectively). However, there was no significant impact of insulin on adult longevity. These findings are of great utility in the biological suppression of Parthenium as it will enhance the effectiveness of this beetle through manipulation of diapause.     

Quantifying the historic contribution of Olympia oysters to filtration in Pacific Coast (USA) estuaries and the implications for restoration objectives

The Olympia oyster, Ostrea lurida Carpenter, was formerly widespread in many US Pacific coast estuaries. Following dramatic declines in the late 1800s and early 1900s, this species is now the focus of renewed restoration efforts. Restoration is undertaken for brood stock rehabilitation as well as a range of ecosystem services such as filtration; however, these ecosystem services are as yet poorly quantified. We present the first laboratory measurements of filtration rates (FR) for O. lurida, to which we fit a model of FR as a function of dry tissue weight and water temperature. We find that O. lurida has a FR at optimum temperature similar to previously established means across oyster species at 1 g dry tissue weight (DTW), but lower than many Crassostrea species. We also find that the allometric exponent relating FR to DTW in O. lurida is lower than the previously published mean across oyster species. Based on our derived filtration rates and historical data, we estimate the historic impact of filtration by O. lurida in five Pacific coast estuaries. We find that historic O. lurida populations did not have the capacity to filter the full volume of the estuary within the estuary residence time in any of the estuaries examined. This result is primarily driven by the low water temperatures and the short estuary residence times that typify the Pacific coast. We conclude that, unlike Crassostrea virginica Gmelin on the Atlantic and Gulf coasts, the Olympia oyster was not historically a dominant force in regulating seston concentrations at large scales in Pacific coast estuaries. Given the differences in the ecological role and habitat structure of these two oyster species, we recommend that analogies between them be drawn with caution. We discuss the implications of our results for developing restoration objectives.     

Effect of photoperiod on a winter and on a summer diapause in two species of cranefly (Tipulidae)

Two craneflies, Tipula subnodicornis and Tipula pagana, both undergo diapause in the final larval instar. The species showed differences in the intensity of diapause and in the timing of the photoperiodic reaction during diapause, that could be related to season. Tipula subnodicornis undergoes a winter diapause that is induced and maintained in its early stages by short photoperiod (L:D:6:18). In the laboratory individuals in the early stages of diapause terminated diapause and pupated earlier when they were exposed to daylengths of, or greater than, 12 hr. However, it is suggested that in the field diapause is broken before the natural daylength is long enough to have any accelerating effect on development. Tipula pagana has a summer diapause which is of greater intensity than that of Tipula subnodicornis and some larvae were maintained for 197 days in the laboratory, without pupating, on an 18 hr daylength. Diapause was broken by a L:D;16:8 photoperiod and development was accelerated by a further decrease in daylength. The acceleration in development rate was attended by a decrease in the variance about the mean date of emergence and resulted in a highly synchronised emergence period. It is suggested that this quantitative response to daylength is particularly important to a species that emerges in the autumn when the temperature in the field is falling.     

中华稻蝗长沙种群的生活史及其卵滞育的进化意义

中华稻蝗Oxya chinensis为重要的水稻害虫,在我国除青海、西藏、新疆、内蒙古等未见报道外,南起海南北至东北均有分布,在许多的分布区域1年发生1代。为探索中华稻蝗长沙种群的生活史及其季节适应特征,通过野外和实验室的研究,调查了其发生代数、孵化率和卵滞育率的季节变化及越冬卵的存活率。结果显示,中华稻蝗长沙种群为1年2代和1年1代混合发生:第1代卵产卵后大部分孵化为若虫而1年完成2代,但亦有19.4% -4.1%的卵不孵化而1年只能完成1世代。第1代成虫于6月上旬至8月上旬羽化,6月下旬至8月中旬产卵;第2代若虫于7月初开始孵化,9-10月羽化为成虫,10月上旬至11月下旬产卵。在室外自然条件下,中华稻蝗长沙种群6-8月(第1代)和10-11月(第2代)所产卵块均为部分滞育,滞育率为30%左右,皆无显著差异。然而,其卵滞育率在12月以后显著降低,仅为6.6%或以下,卵滞育快速地得以解除。因此,包括非滞育卵和滞育解除卵,中华稻蝗长沙种群的越冬卵皆以非滞育状态度过其后的寒冷季节。即使是遭遇长江流域2007年末至 2008年初异常寒冷的冬季,在长沙地区越冬后其卵的存活率亦在98%以上。非滞育状态的中华稻蝗长沙种群越冬卵完全能安全地越冬,其滞育的发生并非是为了提高其耐寒性而安全度过不适环境。并探讨了中华稻蝗长沙种群卵滞育的进化意义。     

Effects of fusicoccin on intact cotton plants (Gossypium hirsutum L.)

Fusicoccin (FC) was applied as a spray to shoots of intact field- and glasshouse-grown cotton plants. Distortions of shoot morphology resulted. Stems and petioles of FC-treated plants were irregular in diameter and twisted, whereas leaf laminae were curled and crinkled. Shoot elongation was inhibited by FC; the effect was dependent upon the concentration and timing of the applications.Abbreviation FC fusicoccin     

Seasonal regulation of dormancy in Chrysopa carnea (Neuroptera)

In Ithaca, New York, diapause incidence in Chrysopa carnea exceeds 50 per cent among adults emerging between 31 August and 3 September. Apparently, decreasing late summer day lengths, which exceed the stationary critical photoperiod in the laboratory, act on the sensitive stages and induce diapause. Full diapause intensity occurs about 2 weeks after adult emergence; complete winter coloration appears approximately 2 weeks later. Photoperiodic stimili in combination with the geographic strain largely determine diapause depth.Decreasing autumn day lengths decelerate diapause development and maintain diapause until the winter solstice. Subsequently, short day lengths and cold temperatures slow diapause development. In nature, neither long days, increasing day lengths, nor chilling hasten diapause termination. Diapause duration is largely determined by the interaction between inducing photoperiod, maintaining photoperiodic and thermal stimuli, and geographic strain. In Ithaca, diapause ends (all response to photoperiod ceases) between 22 January and 12 March.After diapause ends, the animals retain their diapause characteristics until temperatures exceed 4°C. Post-diapause reproductive development in females requires approximately 100 heat units above 4°C; however, below 8°C mating and oviposition are absent. Although the winter coloration remains, mating occurs within 1 day after transfer from 4 to 24°C. Temperature determines the rate at which the green summer colour returns.     

Seasonal cycles in stink bugs (Heteroptera,Pentatomidae) from the temperate zone: Diversity and control

The paper reviews the diversity of seasonal cycles known in stink bugs (Heteroptera, Pentatomidae) from the temperate zone and is based on the data of 43 pentatomid species studied in detail up to date (Saulich and Musolin, 2011). All the seasonal cycles realized by pentatomids in the temperate zone can be divided into two large groups: univoltine and multivoltine cycles. In univoltine cycles, only one generation is annually realized. However, univoltinism of a particular species or population can be ensured by different mechanisms: its control can be endogenous (involving an obligate diapause) or exogenous (environmental, involving a facultative diapause). Furthermore, endogenously controlled univoltine seasonal cycles can include obligate embryonic (egg) diapause (e.g., Picromerus bidens and Apateticus cynicus), obligate nymphal diapause (e.g., Pentatoma rufipes) or obligate adult (reproductive) diapause (e.g., Palomena prasina, Palomena angulosa, and Menida scotti). Exogenously controlled seasonal cycles are more flexible. Many species that are multivoltine in the subtropical or warm temperate zones are univoltine further polewards. In this case, their univoltinism is controlled exogenously, or environmentally. The mechanism often involves such seasonal adaptations as photoperiodic response of facultative winter diapause induction with a high thermal optimum (e.g., Arma custos and Dybowskyia reticulata) or a high critical threshold of winter diapause induction response (e.g., Graphosoma lineatum). The seasonal cycles of some species include not only winter diapause (hibernation) but also summer diapause (aestivation). The diapausing stage can be the same (e.g., Nezara antennata has facultative adult winter and summer diapauses) or different (e.g., Picromerus bidens survives winter in obligate embryonic diapause and spends the hottest period of summer in facultative adult aestivation). All the multivoltine cycles follow the same general pattern, with one, two, or even more directly breeding generation(s) followed by a generation that enters winter diapause. However, this sequence may be complicated by incorporation of specific seasonal adaptations such as aestivation, migrations, different forms of seasonal polyphenism or polymorphism (e.g., seasonal changes of body color), etc. Many stink bugs demonstrate geographic clines of voltinism, producing several generations in the subtropical regions (environmentally controlled multivoltine development) and two or only one generation(s) polewards (environmentally controlled bi- or univoltinism). However, some species demonstrate a strictly bivoltine seasonal cycle: they always produce two annual generations, each with either winter or summer diapause. An example is Nezara antennata which produces two generations and enters facultative winter and summer diapauses. Semivoltine seasonal cycles last more than one year. They are not very rare among insects and are known in true bugs, but have not yet been recorded among pentatomids. Examples of different seasonal cycles are described and discussed in detail. Further discussion is focused on the ecological importance of photoperiodic and thermal responses in cases of natural or artificial dispersal of pentatomids beyond their original ranges. The phytophagous Nezara viridula and the predatory Podisus maculiventris and Perillus bioculatus are used as examples. An attempt is made to compare the phylogeny of Pentatomidae and distribution of realized patterns of their seasonal development. However, it is concluded that reconstruction of phylogenetic relationships cannot yet provide a sufficient basis for prediction of realized seasonal cycles. It is suggested that the terms uni-, bi-, multi-, and semivoltinism should refer to populations rather than species, since the realized patterns of seasonal development often differ between the northern and southern populations of the same broadly distributed species.     

Ecdysteroid levels during post-diapause development and 20-hydroxyecdysone-induced development in male pupae of Mamestra configurata Wlk.

Post-diapause development in male pupae of Mamestra configurata Wlk. was characterized by the appearance of large, transitory peaks of ecdysone (2.8 μg/g live wt) at day 8 and 20-hydroxyecdysone (2.2 μg/g) at day 12 which declined to low levels prior to adult eclosion at day 28.Treatment of diapausing pupae with 20-hydroxyecdysone elicited a progression of dose-dependent physiological and pathological effects, including termination of diapause, development, accelerated development, and accelerated development leading to malformation and death. At a dose of 7.5 μg 20-hydroxyecdysone/g, all treated pupae terminated diapause, developed with little mortality and produced a high proportion of morphologically perfect adults. However, there were no large peaks of ecdysone or 20-hydroxyecdysone in treated pupae, possibly due to feedback inhibition by 20-hydroxyecdysone.At doses greater than 7.5 μg/g, development was accelerated markedly, survival decreased precipitously (0% at 15 μg/g) and the proportion of malformed adults increased sharply. Pupae that received a lethal dose of 20-hydroxyecdysone died almost synchronously after undergoing accelerated development for 18–20 days, indicating that they encounter a common, hormone-induced developmental block. Pupae receiving 15 μg/g also showed no edcysone or 20-hydroxyecdysone peaks, but had a prolonged period of hyperecdysonism which likely caused their accelerated development and death.     

Three Heat Shock Protein Genes from Bactrocera (Tetradacus) minax Enderlein: Gene Cloning,Characterization, and Association with Diapause

Bactrocera (Tetradacus) minax Enderlein is a major pest to wild and cultivated species of citrus. Bactrocera minax produces one generation per year with a long pupal diapause period of over 6 months, which hinders efforts to obtain vast numbers of insects under standard room conditions. Determining the mechanisms of diapause is significantly important for obtaining large quantities of these insects. To characterize the heat shock protein (Hsp) genes of B. minax and to unravel their potential contribution to diapause, we performed 3′ and 5′ RACE to isolate the complementary DNA (cDNA) sequences, bioinformatics to examine the phylogenetic relationships, and real-time quantitative PCR to detect the expression patterns of three Hsp genes during various developmental stages. These results represent the first characterization of the three Hsp genes of B. minax; the open reading frames of Bmhsp23, Bmhsp70, and Bmhsp90 were 510, 1,911, and 1,089 bp, encoding 170, 636, and 363 amino acids, respectively. BmHsp70 and BmHsp90 displayed high identity to previously identified Hsp70 and Hsp90 genes, respectively. BmHsp23 displayed varying similarity, from 28 to 83%, to previously identified small Hsps. Bmhsp23 messenger RNA (mRNA) expression was found to be upregulated during diapause initiation, maintenance, and termination. Bmhsp70 mRNA expression peaked during diapause initiation. Bmhsp90 mRNA expression remained at a relatively low level during deep diapause. Our present results suggest that Bmhsp70 might play an important role in diapause initiation, while Bmhsp23 in diapause initiation and maintenance and Bmhsp90 in diapause regulation. These results improve our understanding of the mechanism of diapause in B. minax at the molecular level.     

Effect of photoperiod on the induction and maintenance of diapause and on development of the predatory bugPodisus maculiventris (Hem.: Pentatomidae)

The predatory bugPodisus maculiventris Say displays a reproductive diapause. In the laboratory, at 23±1°C, when the pre-imaginal stages were reared on larvae ofGalleria melonella L. (Lepidoptera: Pyralidae) under a short photoperiod of 8L: 16D, diapause was induced in all adult females, whereas under a long photoperiod of 16L: 8D none entered diapause. Nymphal development was faster under the diapause-inducing short photoperiod than under the diapause-averting long photo-period. By contrast, embryonic development was faster under the long than under the short photoperiod. Diapause maintenance was also under the control of photoperiod. After a 10-d-period of chilling at 4°C, diapause was quickly terminated in adults kept under long photoperiod whereas it was maintained in most of those kept under short photoperiod. The predation rate of non-diapause or post-diapause adult females was much higher than that of diapause females.     

Cloning and characterization of Methoprene-tolerant(Met)and Kruppel homolog 1(Kr-h1)genes in the wheat blossom midge,Sitodiplosis mosellana

Juvenile hormone(JH),a growth regulator,inhibits ecdysteroid-induced meta-morphosis and controls insect development and diapause.Methoprene-tolerant(Met)and Krippel homolog I(Kr-h1)are two proteins involved in JH action.To gain some insight into their function in development of Sitodiplosis mosellana,an insect pest undergoing obligatory larval diapause at the mature 3rd instar stage,we cloned full-length complemen-tary DNAs of Met and Kr-h1 from this specics.SmMet encoded a putative protein,which contained three domains typical of the bHLH-PAS family and eight conserved amino acid residues important for JH binding.SmKr-h1 encoded a protein showing high sequence homology to its counterparts in other specics,and contained all eight highly conserved Zn-finger motifs for DNA-binding.Expression patterns of SmMet and SmKr hl were de-velopmentally regulated and JH III responsive as well.Their mRNA abundance increased as larvae entered carly 3rd instar,pre-diapause and maintenance stages,and peaked during post-diapause quiescence,a pattern correlated with JH titers in this species.Different from reduced expression of SmMer,SmKr-h1 mRNA increased at mid-to-late period of post-diapause development.Topical application of JH II on diapausing larvac also induced the two genes in a dose-dependent manner.Expression of SmuMer and SmKr-h1 clearly declined in the pre-pupal phase,and was significantly higher in female adults than male adults.These results suggest that JH-responsive SmMet and SmKr-h1 might play key roles in diapause induction and maintenance as well as in post-diapause quiescence and adult reproduction,whereas metamorphosis from larvae to pupac might be correlated with their reduced expression.     

Altitudinal variation in life cycle syndromes of California populations of the grasshopper,Melanoplus sanguinipes (F.)

Summary Life cycles of California populations of the grasshopper, Melanoplus sanguinipes, varied along an altitudinal gradient. Temperature records indicate a longer season at low altitude on the coast, based on computation of degree days available for development, even though summer air temperatures are cooler than at high altitude; this is a result of warm soil temperatures. At high and low altitudes there was a high proportion of diapause eggs oviposited, while intermediate proportions of diapause eggs occurred at mid altitudes. The low altitude, and especially sea level, populations diapaused at all stages of embryonic development, while at high altitudes most diapause occurred in the late stages just before hatch. Diapause was more intense at high altitudes. One result of diapause differences was delayed hatching in the sea level population. Nymphal development and development of adults to age at first reproduction were both accelerated at high altitude relative to sea level. At lower temperatures (27° C) there was a tendency for short days to accelerate development of sea level nymphs, but not high altitude nymphs. In both sea level and high altitude grasshoppers, short days accelerated maturation of adults to onset of oviposition at warm temperature (33° C); there was little reproduction at 27° C. Population differences for all traits studied appear to be largely genetic with some maternal effects possible. We interpret diapause variation at low and mid altitudes to be responses to environmental uncertainty and variations in development rates to be adaptations to prevailing season lengths.