Hydrocarbon profiles of diapausing and reproductive adult face flies (Musca autumnalis)

Hydrocarbons present on the cuticle surface of adult face flies, Musca autumnalis, were identified by GC-MS and quantified by GC. Hydrocarbons consisted of n-, monomethyl, and dimethyl alkanes ranging in chain length from 23–29 carbons. Also present were monounsaturated alkenes with chain lengths of 23, 25, 27, and 29 carbons. Wild-caught flies were extracted and hydrocarbon profiles determined for both diapausing and reproductive adult males and females. Few qualitative differences were found between males and females in the hydrocarbon profile. Differences in percent composition were found between diapausing and reproductive flies in monounsaturated alkenes, 4 and 45%, n-alkanes, 24 and 37%, monomethylalkanes, 57 and 15%, and dimethylalkanes, 15 and 2%, respectively, for females. A small difference was found in the total amount of hydrocarbon present, 7.3 ± 0.6 and 9.7 ± 1.1 μg/fly, between diapausing and reproductive female flies, respectively. Adult males also exhibited a similar change in hydrocarbon profile and amount between diapausing and reproductive flies. A laboratory strain of face flies originating in Minnesota was also analyzed, and again similar differences were observed in both male and female flies that were kept under a reproductive or diapause condition. Arch. Insect Biochem. Physiol. 37:206–214, 1998. © 1998 Wiley-Liss, Inc.     

Cold tolerance in diapausing and non-diapausing stages of the flesh fly, Sarcophaga crassipalpis

ABSTRACT. Supercooling points (SCP) and low temperature tolerance were determined for larval, pupal and adult stages of Sarcophaga crassipalpis Macquart (Diptera: Sarcophagidae). No stage tolerates tissue-freezing. Ontogenetic changes in SCP profiles are similar for comparable developmental stages of diapause and non-diapause groups. Feeding larvae have SCPs near -7°C which decrease to -11°C in the postfeeding wandering phase of the final larval instar. The lowest SCPs are recorded for pupae at -23°C. The capacity to survive at -17°C varies with age of the diapausing pupae: 10-day-old pupae are less cold tolerant than pupae that have been in diapause for 45–80 days. Although the SCP of non-diapausing pupae is as low as in diapausing pupae, non-diapausing pupae are extremely sensitive to low temperature exposure and do not survive to adult eclosion when exposed to -17°C for as little as 20 min. The use of hexane to break pupal diapause has no effect on SCPs or low temperature tolerance.     

Diapausing pupae of the flesh fly Sarcophaga crassipalpis (Diptera: Sarcophagidae) are more resistant to inoculative freezing than non-diapausing pupae

The resistance of diapausing (overwintering) and non‐diapausing (summer) Sarcophaga crassipalpis (Diptera: Sarcophagidae) pupae to inoculative freezing was examined. Although both types of pupae resisted inoculative freezing after 24‐h submergence in water, diapausing pupae were overall significantly more resistant than non‐diapausing pupae. Exposing the thin pupal cuticle by removing the ends of the puparial case eliminated the capacity of both pupal types to resist inoculative freezing, indicating that resistance to inoculative freezing resides with the puparium. Pupae submerged in surfactant solution were significantly less resistant to inoculative freezing than those submerged in water. Furthermore, the puparial water content of pupae submerged in surfactant solution was significantly greater than that of puparia from pupae submerged in water. Surfactant may have promoted inoculative freezing by facilitating the spread of water over the surface of and into the puparium, thereby creating bridges between external ice and pupal body fluids. Extracting puparial surface lipids with chloroform/methanol (2 : 1, v:v) decreased the resistance of non‐diapausing pupae to inoculative freezing but did not significantly affect that of diapausing pupae. This finding indicates that the puparium of diapausing pupae contains protection against inoculative freezing separate from its surface lipids. This barrier may be important in protecting the freezing‐intolerant overwintering pupae against inoculative freezing within their soil hibernaculum.     

Cold-hardiness: a component of the diapause syndrome in pupae of the flesh flies, Sarcophaga crassipalpis and S. bullata

ABSTRACT. Diapausing pupae of Sarcophaga crassipalpis Macquart and S. bullata Parker reared at 20 or 25C readily survive exposure to - 10C for at least 25 days. In contrast, non-diapausing pupae produced by a variety of means are consistently intolerant of the low temperature. Non-diapausing pupae are not immediately killed by exposure to -10C: pupae exposed to the low temperature for up to 3 days proceed with pharate adult development but ultimately die before adult eclosion. Unlike many temperate zone insects, diapausing flesh fly pupae do not require a period of chilling for induction of cold-hardiness, and the attribute of cold-hardiness cannot be separated from other features of the diapause syndrome. Some cold-hardiness is already acquired during the third larval instar: diapause-destined larvae exposed to -10C are more successful in pupariating than non-diapause-destined larvae of the same age.     

Cold shock and rapid cold-hardening of pharate adult flesh flies (Sarcophaga crassipalpis): effects on behaviour and neuromuscular function following eclosion

Abstract. Little is known about the nature of injury due to cold shock, or its prevention by rapid cold-hardening, in insects. To understand these phenomena better at the system level, physiological and behavioural comparisons were made between control, cold shock injured, and rapidly cold-hardened flesh flies, Sarcophaga crassipalpis Macquart (Diptera, Sarcophagidae). Cold shock impaired the proboscis extension reflex in response to 0.125,0.5 and 1.0 M sucrose solutions. Cold shock-injured flies were unable to groom effectively and spent only 12.5% of the first 5 min following general dust application producing ineffectual leg movements. In contrast, control and rapidly cold-hardened flies exhibited normal grooming behaviour spending 92.4% and 94.1% of the first 5 min following generalized dust application grooming. Cold shock also decreased the mean resting membrane potential of tergotrochanteral muscle fibres from -65.9 mV in control flies to -41.6 m V. Conduction velocities of the three motor neurone populations innervating the tergotrochanteral muscle were all significantly lower in cold-shocked flies than in control or rapidly cold-hardened flies. Finally, cold shock impaired neuromuscular transmission as evidenced by a lack of evoked end plate potentials.     

Reproductive and developmental consequences of a diapause maternal effect in the flesh fly, Sarcophaga bullata

Abstract Progeny of Sarcophaga bullata produced from mothers with a history of short day will not enter pupal diapause even if they are reared in a strong diapause-inducing environment (LD 12:12 h at 20^oC). Short-day exposure and diapause commitment are normally inseparable, but this maternal effect provides a tool for examining separately the effect of photoperiod and diapause commitment. Duration of the wandering period of the third instar is longer in diapause-destined larvae than in non-diapause-destined larvae, and fecundity of flies that have experienced pupal diapause is lower than in long-day flies that have not been through diapause. The puparia of diapausing pupae contain more hydrocarbons than puparia of nondiapausing pupae, and this contributes to higher rates of net transpiration for the nondiapausing flies. Flies showing the maternal effect (short-day experience but no diapause) show an intermediate response: length of wandering, fecundity rate and quantities of puparial hydrocarbon are between the extremes observed in the other two groups of flies. Thus, the maternal effect switches the developmental programme to nondiapause, but the progeny retain some characteristics of diapause. Evidence from reciprocal crosses indicates that the photoperiodic history of the female, rather than the male, is responsible for the influence on fecundity.     

Haemolymph protein reserves of diapausing and nondiapausing codling moth larvae, Cydia pomonella (L) (Lepidoptera: Tortricidae)

Haemolymph from diapausing codling moth larvae contain a dominant soluble protein, which is of minor significance in the haemolymph of nondiapausing larvae. This haemolymph protein is accumulated during the ultimate larval instar and its concentration is maintained throughout diapause development. Larvae induced into a diapause-like condition following topical treatment with a juvenile hormone mimie stored the haemolymph protein.     

Intracellular freezing, viability, and composition of fat body cells from freeze-intolerant larvae of Sarcophaga crassipalpis.

Although it is often assumed that survival of freezing requires that ice formation must be restricted to extracellular compartments, fat body cells from freeze-tolerant larvae of the gall fly, Eurosta solidaginis (Diptera, Tephritidae) survive intracellular freezing. Furthermore, these cells are highly susceptible to inoculative freezing by external ice, undergo extensive lipid coalescence upon thawing, and survive freezing better when glycerol is added to the suspension medium. To determine whether these traits are required for intracellular freeze tolerance or whether they are incidental and possessed by fat body cells in general, we investigated the capacity of fat body cells from nondiapause-destined and diapause-destined (i.e., cold-hardy) larvae of the freeze-intolerant flesh fly Sarcophaga crassipalpis (Diptera, Sarcophagidae) to survive intracellular freezing. Fat body cells from both types of larvae were highly susceptible to inoculative freezing; all cells froze between -3.7 to -6.2 degrees C. The highest rates for survival of intracellular freezing occurred at -5 degrees C. The addition of glycerol to the media markedly increased survival rates. Upon thawing, the fat body cells showed little or no lipid coalescence. Fat body cells from E. solidaginis had a water content of only 35% compared to cells from S. crassipalpis larvae that had 52-55%; cells with less water may be less likely to be damaged by mechanical forces during intracellular freezing.     

Three new species of Sarcophaga Meigen found during ecological studies on flesh flies (Diptera: Sarcophagidae) in Thailand

Three new species of Sarcophaga Meigen, 1826 are described from Thailand: Sarcophaga ( Sarcosolomonia ) circa sp. nov., S . ( Mehria ) lanna sp. nov. and S . ( Rosellea ) suthep sp. nov.     

大斑芫菁滞育幼虫在滞育不同阶段体内糖类和醇类含量的变化

在以卵滞育的昆虫中昆虫滞育时的生理代谢特点已经得到了大量研究。本文对以末龄幼虫（5龄）滞育的大斑芫菁Mylabris phalerate（Pallas）在不同滞育阶段体内糖类和醇类代谢的特征进行了研究。结果表明： 滞育个体血淋巴中的海藻糖含量高于非滞育个体,且随滞育时间的加大逐渐升高,滞育5个月时达到最大值,为5.61 μmol/mL。糖原的含量随滞育的进程逐渐减少,滞育初期（0.5个月）为0.72 mg/mL,到滞育末期（5个月）时仅为0.1 mg/mL。滞育个体脂肪体中的海藻糖含量都高于非滞育个体,滞育1个月时为非滞育个体的3倍,至滞育末期时达非滞育个体的5倍,为2.5 μmol/g脂肪体。糖原含量总体变化趋势是随滞育时间的加大逐渐减少,滞育早期和中期都高于非滞育个体。在滞育过程中血淋巴积累的小分子多元醇主要为甘油,其次是山梨醇;而在脂肪体中主要为甘油,其次是甘露醇,少量积累山梨醇：表明大斑芫菁滞育幼虫主要积累的是海藻糖和一些小分子多元醇。滞育幼虫在准备滞育时储备了大量糖原,这些糖原可能为滞育期间海藻糖、山梨醇和甘油的代谢提供了原料。     

Postharvest disinfestation of diapausing and non-diapausing twospotted spider mite (Tetranychus urticae) on persimmons: hot water immersion and coolstorage

The mortality response of diapausing and non-diapausing twospotted spider mite (Tetranychus urticae Koch) on persimmons to hot water immersion treatments between 44 and 54 °C was examined, for potential as a quarantine treatment. The mean immersion time for mean 99% mortality (LT₉₉) of diapausing mites at 44 °C was 211 min, and this time decreased with increasing temperature to 3.6 min at 54 °C. Non-diapausing mites were found to be less tolerant to temperatures below 48 °C, with an estimated LT₉₉ of 102 min at 44 °C, but had similar thermotolerance above 48 °C. In 47 °C water the immersion time required to kill 99% of diapausing mites was estimated at 67 min. This time was not reduced by subsequent coolstorage at 0 °C for up to eight weeks. Rather, coolstorage had the effect of keeping mites alive, relative to LT₉₉ estimates calculated for mites stored at 20 °C. Similarly the thermotolerance of mites did not change with increased time in diapause, even though mites in diapause for 12 weeks had high control mortality. Hot water immersion appears to be a potentially useful disinfestation method for persimmons.     

即时浸酸显著提高滞育性家蚕卵辅酶Ⅰ和Ⅱ含量

即时浸酸在阻止家蚕Bombyx mori卵滞育发动的同时, 提高了其呼吸耗氧量, 抑制了山梨醇积累。本研究利用HPLC法测定了家蚕滞育卵和5 min即时浸酸滞育性卵中辅酶Ⅰ和Ⅱ含量。结果表明： 产下后24-72 h, 家蚕滞育卵中NAD, NADH, NADP和NADPH含量分别下降了30%, 37%, 50%和4%; 而即时浸酸滞育性卵中分别增加了77%, 46%, 142%和241%。不过, 即时浸酸并未显著改变滞育性家蚕卵中NADH/NAD和NADPH/NADP比值。据此推测, 即时浸酸提高滞育性家蚕卵辅酶Ⅰ含量与其呼吸耗氧量增加有关; 即时浸酸显著提高辅酶Ⅱ含量与山梨醇积累抑制无关, 而主要与生物合成加强有关。     

Genetic patterns in the Lathyrus pannonicus complex (Fabaceae) reflect ecological differentiation rather than biogeography and traditional subspecific division

The endangered European relict species complex Lathyrus pannonicus shows distinct morphological variation, reflected by the number of subspecies recognized, and complicated patterns of genetic variation. The traditionally recognized subspecies appear to possess different ecological preferences and disjunct distributions, particularly in the western range of the species. In this study, L. pannonicus was investigated by the correlation of distance matrices based on phytosociological, ecological, molecular and morphological data. Ecological characteristics of selected stands of L. pannonicus throughout Europe were assessed using ‘Ellenberg values’ of all the constituent taxa in phytosociological relevés. Genetic distances were calculated using recently developed methods to analyse high degrees of intra‐individual nuclear‐encoded internal transcribed spacer variability. We found that the remarkable genetic (and morphological) diversity in L. pannonicus could not be explained solely by the fragmentation of the distributional range. Instead, patterns of morphological and genetic differentiation were a reflection of the moisture regime in the sampled stands. Two major lineages could be identified: (1) a lineage adapted to dry conditions (Ellenberg indicator F‐value ≤ 3.5) and (2) a lineage preferring moist conditions (F‐value ≥ 4.5). Although both lineages occurred in close proximity in the Pannonian area, they appeared to be reproductively isolated in general. Further data are needed to determine whether these genetically and ecologically defined lineages, or ecospecies, within the L. pannonicus species complex can be formalized as (Linnaean) species or subspecies. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 165 , 402–421.     

Effect of soil burial depth and wetting on mortality of diapausing larvae and patterns of post-diapause adult emergence of sorghum midge, Stenodiplosis sorghicola (Coquillett) (Diptera: Cecidomyiidae)

Abstract  In south-eastern Queensland, Australia, sorghum planted in early spring usually escapes sorghum midge, Stenodiplosis sorghicola , attack. Experiments were conducted to better understand the role of winter diapause in the population dynamics of this pest. Emergence patterns of adult midge from diapausing larvae on the soil surface and at various depths were investigated during spring to autumn of 1987/88–1989/90. From 1987/88 to 1989/90, 89%, 65% and 98% of adult emergence, respectively, occurred during November and December. Adult emergence from larvae diapausing on the soil surface was severely reduced due to high mortality attributed to surface soil temperatures in excess of 40°C, with much of this mortality occurring between mid-September and mid-October. Emergence of adults from the soil surface was considerably delayed in the 1988/89 season compared with larvae buried at 5 or 10 cm which had similar emergence patterns for all three seasons. In 1989/90, when a 1-cm-deep treatment was included, there was a 392% increase in adult emergence from this treatment compared with deeper treatments. Some diapausing larvae on the surface did not emerge at the end of summer in only 1 year (1989/90), when 28.0% of the larvae on the surface remained in diapause, whereas only 0.8% of the buried larvae remained in diapause. We conclude that the pattern of emergence explains why spring plantings of sorghum in south-eastern Queensland usually escape sorghum midge attack.     

Rates of metabolism in diapausing and reproductively active tropical butterflies, Euploea core and Euploea sylvester (Lepidoptera: Nymphalidae)

Abstract.  Although the ecology of diapause has been widely studied in the field, the underlying physiological responses occurring in tropical diapausing insects remain virtually unexplored. This is especially the case with rates of respiration in diapausing tropical insect species. The present study compares rates of metabolism, as assessed by measurement of carbon dioxide production, between two species of diapausing and reproductively active tropical butterflies, Euploea core (W.S Macleay) and Euploea sylvester (Fabricius) , independent of temperature. Measurement of metabolism over a day-time/night-time regime confirms that these tropical butterflies display a diurnal rhythm in accordance with many other tropical and temperate insect species, regardless of developmental state. In addition, diapausing Euploea butterflies display rates of carbon dioxide production only 28% lower than those of reproductively active butterflies, and can terminate diapause within days of receiving the correct cues. Maintaining a similar metabolic rate throughout diapause, as well as a rapid termination of diapause, would enable these tropical butterflies to respond immediately to larval host plant resources, without the disadvantage of missing optimum conditions, allowing the species to maximize their reproductive potential.     

Reproductive responses to photoperiod and temperature by diapausing and nondiapausing populations of Sesamia nonagrioides Lef. (Lepidoptera − Noctuidae)

Abstract.  The influence of long- and short-day cycles on ovipostion and egg hatch of the corn stalk borer, Sesamia nonagrioides were investigated at a range of temperatures. Oviposition was suppressed when insects are exposed to long days through their immature stages and then transferred to short days after mating. Moreover, mean oviposition and egg hatch increased from 15 to 27.5 °C, whereas oviposition declined significantly at 30 °C at both photoperiodic regimes. Females derived from a diapausing population exposed to long days after mating showed a significantly higher egg production compared to females derived from a nondiapausing population. However, when females from a diapausing population were left to oviposit under short days, fewer eggs were produced compared to those exposed to long days after mating. Thus, photoperiod appears to affect reproductive traits of this species in a quantitative manner. Larval diapause duration is positively correlated with fecundity of the adults. There is also a positive correlation between pupal weight of individuals derived from a diapausing population and the postdiapause fecundity of adults.     

Comparison of cold hardiness and sugar content between diapausing and nondiapausing pupae of the cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

Abstract. To understand overwintering of the cotton boll worm Helicoverpa armigera, cold hardiness and sugar content are compared between diapausing and nondiapausing pupae. Diapausing and nondiapausing pupae reared at 20 °C under short and long photoperiods are acclimatized with a reduction of 5 °C per 5 days to 0 °C. When the acclimation temperature reaches 0 °C, the survival of diapausing pupae is assessed. The survival gradually decreases as the period of treatment progresses and approximately half survive for 112 days. However, nondiapausing pupae survive only 14 days after exposure to 0 °C. The surpercooling points of nondiapausing, diapausing and acclimatized pupae are approximately −17 °C. The major sugars contained in pupae are trehalose and glucose. Even though trehalose contents in diapausing pupae (initial level: 0.6 mg 100 mg⁻¹ fresh weight) increase significantly during cold acclimation and continue increasing until 58 days after exposure to 0 °C (maximum level: 1.8 mg 100 mg⁻¹), glucose is maintained at low levels (0.02 mg 100 mg⁻¹) for 56 days at 0 °C. However, glucose contents increase (maximum level: 0.8 mg 100 mg⁻¹) with decreasing contents of trehalose 84 days after exposure to 0 °C. Glycogen content gradually decreases during cold acclimation. When nondiapausing pupae are acclimatized with a reduction of 5 °C per 5 days to 5 °C from the beginning of pupation until the eyespots move, trehalose content increases (maximum level: 1.0 mg 100 mg⁻¹). Glucose contents in nondiapausing pupae increase before eclosion (0.09 mg 100 mg⁻¹). From these results, diapausing pupae of H. armigera can overwinter in regions where average winter temperatures are higher than 0 °C, but nondiapausing pupae cannot.     

Comparison of the effects of pyrokinins and related peptides identified from arthropods on pupariation behaviour in flesh fly (Sarcophaga bullata) larvae (Diptera: Sarcophagidae)

Peptides from the pyrokinin/PBAN family and some structurally related compounds identified in various arthropods were tested for acceleration of puparial contraction in flesh fly larvae. Modifications of behavioural patterns of pupariation were further studied for the active compounds using a behavioural analysis based on the recording of changes in tension of the cuticle. Nine peptides belonging to the pyrokinin/PBAN family (Lem-PK, Pea-PK-5, Lom-PK II, Hez-PBAN, Bom-DH-I), identified in five different insect species, two pyrokinin peptides derived from the genome of Drosophila melanogaster (capa-3, and hugin), and two pyrokinins identified from the white shrimp Penaeus vannamei were very active in the pupariation assay, with threshold doses within the range of 0.1-5.0 pmol larva(-1). High activity was also detected for a related peptide ETH1 from Drosophila. All of these peptides share a C-terminal PRLamide, which is essential and sufficient for the activity. Interestingly, two other structurally related peptides from Drosophila--ETH2 and capa-1--which feature conservative changes (Ile and Val, respectively) at the C-terminal Leu position, were inactive within a physiological range of concentrations. It is clear that the receptor mediating the acceleration of puparial contraction behaviour is sensitive to the introduction of greater steric bulk at the C-terminal Leu position. The peptides that accelerated pupariation showed very similar patterns of muscular and cuticular activity.     

Geographic variation in the incidence of pupal diapause in Asian and Oceanian species of the flesh fly Boettcherisca (Diptera: Sarcophagidae)

ABSTRACT. The incidence of pupal diapause was examined in nine species of the genus Boettcherisca Rohdendorf ( B.peregrina, B.javanica, B.nathani, B.septentrionalis, B. karnyi, B. koimani, B. timorensis, B. formosensis and B.invaria ) collected from various localities in East Asia and Oceanian islands.
Colonies of B.septenrionalis, B. nathani and B.peregrina obtained from temperate regions of Asia and those of B. formosensis and B.peregrina from the continental subtropics entered pupal diapause in response to photoperiod at 20C.
The incidence of pupal diapause showed a geographic gradient in B.peregrina. No photoperiodically induced diapause was observed in the other five species which are indigenous to the tropical or subtropical habitats.
Different species of Boettcherisca seem to have evolved their pupal diapause independently of one another as an ecophysiological mechanism which enabled those species to expand from the tropical to temperate region.