Population dynamics ofLuehdorfia japonica Leech (Lepidoptera: Papilionidae)

Mortality processes from egg to final instar larval stage are examined in the papilionid butterfly Luehdorfia japonica for two generations in a natural populations. Special attention is given to the effects of initial egg cluster size on the survival rate by the 3rd instar. Mean egg cluster sizes for the two generations were 11.3 and 10.7. The hatching rate was not affected by the egg cluster size. Up to 3rd instar, larvae in a group were more likely to die en masse rather than to die individually, whereas most larvae in later instars died independently. The egg clusters of the average (and the most frequent) size class (11±1) had the second highest survival rate until the 3rd instar. A slightly higher survival rate occurred in clusters a little larger (14±1). The average size clusters were least likely to be exterminated and about 70% of them produced at least one individual surviving to the 3rd instar. Factors affecting the observed mortality patterns were discussed.     

平卧川牛漆甾酮对小菜蛾生长发育的影响(英文)

平卧川牛漆甾酮是紫背金盘中的主要植物蜕皮甾类 ,在筋骨草属植物中普遍存在。试验结果表明 ,用 5 0mg L平卧川牛漆甾酮处理小菜蛾卵 ,其孵化受到抑制 ,总孵化率为 94.7% ,显著低于对照的 1 0 0 %孵化。平卧川牛漆甾酮对幼虫具有弱的毒杀活性和良好的拒食活性 ,且与浓度相关。小菜蛾的生长发育也受平卧川牛漆甾酮的影响。用高于 5 0mg L浓度处理幼虫 ,其生长受抑及蛾的产卵量下降 ,而较低浓度处理则有利于幼虫生长 ,卵量提高。这种双重作用可能是由于平卧川牛漆甾酮的激素活性和拒食活性的作用结果 ,后者导致昆虫营养不良。处理幼虫后 ,试虫的化蛹和羽化受阻。小菜蛾对平卧川牛漆甾酮比 2 0 羟基蜕皮酮更敏感。     

模拟降雨对草地贪夜蛾卵和幼虫的影响

为探究降雨对草地贪夜蛾Spodoptera frugiperda种群的影响,本研究通过室外模拟降雨研究了雨水冲刷对草地贪夜蛾卵和幼虫的影响。结果表明：在4种不同降雨强度0 mm/h（对照）、10.2 mm/h（中雨）、26.5 mm/h（暴雨）、42.8 mm/h（大暴雨）处理下,卵块的掉落率随着降雨强度的增加而增加;在暴雨、大暴雨条件下卵块的孵化率分别为75.14%、43.58%,显著低于对照和中雨;对比有无鳞毛层覆盖的卵块之间的掉落率和孵化率,二者在各个降雨强度之间差异不显著;对比玉米叶片不同位置卵块的掉落率和孵化率,在中雨降雨强度影响下,二者差异不显著,而在暴雨、大暴雨条件下,玉米叶片背面卵块的掉落率低于正面,孵化率高于正面。此外,在相同的降雨强度下,草地贪夜蛾幼虫（2龄、3龄、4龄、5龄）的掉落率随着龄期的增加而降低;当降雨强度增加时,3龄幼虫的掉落率增加。结果表明降雨,特别是暴雨和大暴雨,对草地贪夜蛾的卵和幼虫均有不利影响,为预测草地贪夜蛾种群提供一定依据。     

Chemical constituents and energy content of some latex bearing plants

The latex bearing plants Plumeria alba, Calotropis procera, Euphorbia nerrifolia, Nerium indicum and Mimusops elengi were evaluated as potential renewable sources of energy and chemicals. Plant parts (leaf, stem, bark) and also whole plants were analyzed for elemental composition, oil, polyphenol, hydrocarbons, crude protein, alpha-cellulose, lignin and ash. The dry biomass yields were between 4.47 and 13.74 kg/plant. The carbon contents in whole plants varied from 38.5% to 44.9%, while hydrogen and nitrogen contents varied from 5.86% to 6.72% and 1.26% to 2.34%, respectively. The bark of the plants contained the highest amount of hydrocarbons (1.78-3.93%) and the leaves contained the lowest amounts (0.26-1.82%). The unsaponifiable materials and fatty acids in the oil fractions of whole plants ranged from 22.8% to 56.4% and 24.7% to 58.7%, respectively. The highest gross heat value was exhibited by C. procera (6145 cal/g) and the lowest by N. indicum (4405 cal/g). Hydrocarbon fractions were characterized by IR and (1)H-NMR and by thermogravimetric analyses. The activation energy (E(a)) in the third stage of decomposition was the greatest in the hydrocarbon fraction obtained from M. elengi (16.40 kJ mol(-1)) and the lowest for C. procera (3.96 kJ mol(-1)). The study indicated that the plant species might be suitable as alternative source of hydrocarbons and other phytochemicals.     

Effect of tomato fruit cultivar and ripening stage on Bactrocera tryoni (Froggatt) egg and larval survival

In studies of frugivorous tephritids, determining when offspring (i.e. egg and three larval instars) mortality occurs within the fruit can greatly improve the mechanistic understanding of the fly/host interaction. Previous research has demonstrated that the Queensland fruit fly, Bactrocera tryoni, has differential offspring performance in two tomato cultivars Cherry and Roma, but when juvenile mortality was occurring was not determined. We examined B. tryoni egg and larval survival in three different ripening stages (immature-green (IG), colour-break (CB) and fully-ripe (FR)) of Cherry and Roma tomato cultivars through destructive fruit sampling at 72 and 120 hr for eggs, and 48 (1st instar), 96 (2nd instar) and 120 hr (3rd instar) after fruit inoculation with neonates for larvae. Cultivar and ripening stage had no significant effect on egg survival, nor larval survival at 48 hr: the overall percentage of egg survival was at least 80% across all treatments, while 1st-instar larval was less than 52% across all treatments. In immature-green tomatoes of both varieties, nearly all mortality occurred during the first and second instars, but at 96 and 120 hr, there were significant interaction effects between cultivar and ripening stage on larval survival. In both colour-break Cherry and Roma tomatoes, there was significant larval mortality between 96 and 120 hr. However, in fully-ripe Cherry, no further significant larval mortality happened after 48 hr, while in fully-ripe Roma significant larval mortality occurred between the first and second larval instars but not thereafter. The difference in timing of larval mortality with ripening stage provides indirect evidence of active fruit defence which is strongest in immature-green fruit, less in colour-break fruit and absent in fully-ripe fruit.     

Toxicity of Bacillus thuringiensis beta-exotoxin to three species of fruit flies (Diptera: Tephritidae)

The current study describes toxic effects of the Bacillus thuringiensis beta-exotoxin toward 3rd instars of 3 fruit fly species: Anastrepha ludens (Loew), A. obliqua (Macquart), and A. serpentina (Wiedemann). The beta-exotoxin was highly toxic to all 3 species tested, with LC50 values calculated as 0.641, 0.512, and 0.408 microgram/cm2 of filter paper used to expose the larvae, for A. ludens, A. obliqua, and A. serpentina, respectively. Exposure to beta-exotoxin was associated with an increase in the incidence of deformed pupae. The adult survivors from beta-exotoxin treatments showed no negative effects in terms of their longevity, fecundity, or egg eclosion (fertility). We conclude that the beta-exotoxin may have potential as a control agent for fruit fly pests.     

Studies on the biology of Argas (A.) reflexus (Fabricius, 1794) (Acari: Ixodida: Argasidae). 2. Effect of alternating temperatures on embryonic development and egg hatch.

The paper presents the results of observations on the effect of temperature alterations between 9 degrees C and 30 degrees C every 6 and 12 hours, respectively, on the embryonic development and egg hatch of Argas (A.) reflexus. No effect of the frequency of temperature changes on the percentage of egg mortality, embryo mortality, abnormal egg hatching, or egg hatching into morphologically normal larvae was observed. The experiments showed that in changes temperature have a particularly detrimental effect on the eggs prior to blastulation.     

Mortality of second-instar larvae of Tuta absoluta produced by the hexane extract of Lycopersicon hirsutum f. glabratum (PI 134417) leaves

1 The mortality resulting from exposure of second‐instar larvae of Tuta absoluta to a hexane extract of Lycopersicon hirsutum f. glabratum (PI 134417) leaves was evaluated in the laboratory. 2 A crude hexane extract was fractionated on a silica gel column to produce 17 fractions. The toxicity of the fractions was evaluated on T. absoluta larvae at 2 and/or 6 mg/10 larvae/Petri dish along with a control. 3 Only two fractions, 4.50 and 10.18% of the total hexane extract, were found to result in very high mortality of second‐instar T. absoluta. 4 All the 17 fractions were analysed by capillary gas chromatography/mass spectrometry (GC/MS). The two most toxic fractions were virtually identical and contained mainly undeca‐2‐one (2‐UD) and trideca‐2‐one (2‐TD). 5 A third major sub‐fraction 13 (50.73% of the total hexane extract) was further fractionated on a silica gel column to obtain five additional sub‐fractions. The toxicity of all the five sub‐fractions was evaluated using second‐instar T. absoluta at 2 mg/10 larvae/Petri dish and also analysed by GC/MS. The most toxic sub‐fractions contained mostly 2‐UD and 2‐TD. 6 The results suggest that 2‐UD and 2‐TD could be related to resistance of L. hirsutum to T. absoluta.     

Effect of a high dose of three antibiotics on the reproduction of a parthenogenetic strain of Folsomia candida (Isotomidae: Collembola)

Folsomia candida Willem (Isotomidae: Collembola) is an edaphic parthenogenetic species commonly used in ecotoxicity studies. We exposed F. candida to a high dose of three antibiotics, tylosin, ampicillin, and oxytetracycline, that target different bacterial groups. Possible toxic effects were assessed through egg production, hatching, and body size. All three antibiotics caused toxic effects. Treatment with oxytetracycline proved the most toxic. This group showed the smallest body size and lowest number of eggs laid, likely the result of a combination of antibiotic toxicity and avoidance of the antibiotic spiked food. Active toxin avoidance by F. candida in toxicological assays may play a role in minimizing their exposure to toxic compounds. Despite the administration of high doses of oxytetracycline, F. candida individuals remained infected with the intracellular bacteria Wolbachia indicating that this strain is resistant to this antibiotic or that the host or its gut flora had detoxified the compound. An increase in percent egg hatch with time was seen in the ampicillin and oxytetracycline treatments, indicating a possible accommodation of the host and/or gut-flora to these antibiotics.     

EFFECTS OF CYASTERONE ON GROWTH AND DEVELOPMENT OF DIAMONDBACK MOTH,PLUTELLA XYLOSTELLA (L.)*

Abstract Cyasterone is the main phytoecdysteroid component from cultured plants of Ajuga nipponensis, and common in other Ajuga species. Results showed that when treated with 50 mg/L cyasterone, the egg hatching of diamondback moth was retarded. The total percentage of eggs hatched in treatment was 94.7%, significantly less than that in control, which was 100%. Low toxicity and good antifeeding activity to the 3rd instar larvae were exhibited, which are dependent upon concentration. The growth and development of diamondback moth were affected by cyasterone. It was found that, at concentrations higher than 50 mg/L cyasterone, the larval growth and egg production were inhibited; while promoted at lower concentrations. This dual role of cyasterone might be attributed to its hormonal activity and antifeeding activity, which resulted in poor nutrition. The pupation and eclosion were hindered by treatment of larvae. This insect species was more susceptible to cyasterone than 20‐hydroxyecdysone.     

Repellency and toxicity of extract from Francoeria crispa (Forsk.) to Eutetranychus orientalis (Klein) (Acari: Tetranychidae)

Laboratory bioassays were conducted to characterise the activity of the extract Francoeria crispa (Forsk.) (Family: Compositae) against the citrus brown mite, Eutetranychus orientalis (Klein). Ethyl acetate was tested for preparing the crude extract of F. crispa. The extract was tested for its toxicity against eggs and adult females of the pest E. orientalis. Ethyl acetate extract of F. crispa affected the behaviour, toxicity and fecundity of females under laboratory conditions. The extract had similar toxic effects on egg stage and adult females of E. orientalis (LC₅₀ = 0.00050 g/ml), respectively. Leaf discs treated with increasing concentrations of ethyl acetate extract of F. crispa showed a high percentage of repellency (97.45%), respectively. Treated females with LC₅₀ concentration of ethyl acetate extract showed a higher remarkable percentage of mortality as well as a reduction in the total number of eggs laid during 7 days. Ten isolated fractions of ethyl acetate crude extract from F. crispa were detected. The results clearly indicate that the isolate number (10) was the most toxic isolate on eggs and females of E. orientalis (LC₅₀ = 0.00014 and 0.000125 g/ml), respectively.     

诱导水稻抗褐飞虱的化学激发子筛选

【目的】化学激发子具有毒性低、不易产生抗药性等特点,因此开发基于化学激发子的害虫防控技术,能够降低农药的使用量,促进农业生产的可持续发展。本研究旨在筛选能够诱导水稻产生对褐飞虱Nilaparvata lugens抗性的化学激发子。【方法】将茉莉酸(JA)、茉莉酸甲酯(MeJA)、水杨酸(SA)、水杨酸甲酯(MeSA)、油菜素内酯(BR)、苯甲酸苄酯(BB)、独脚金内酯(SLs)、萘乙酸(NAA)、吲哚丁酸(IBA)、草酸钠(SO)、硅酸钾(PS)和叶枯唑(Bis)12种化合物以根吸或叶鞘涂抹处理水稻,测定这些化合物处理水稻后褐飞虱的卵孵化率和24 h总产卵量。【结果】12种候选化合物中,仅茉莉酸甲酯、油菜素内酯和苯甲酸苄酯对褐飞虱卵孵化率和24 h总产卵量有显著影响。5 mg/L MeJA根吸处理水稻使褐飞虱的卵孵化率显著降低(达58.8%,降低了20.1%),而0.5 mg MeJA叶鞘涂抹处理水稻同时降低了褐飞虱的卵孵化率(达53.3%,降低了35.4%)和24 h总产卵量(达203.5粒/株,降低了15.6%),且其涂抹的浓度越高,褐飞虱的卵孵化率和24 h总产卵量越低。5 mg/L BR根吸处理水稻可以显著降低褐飞虱的卵孵化率(达59.5%,降低了22.1%),但是不影响褐飞虱的24 h总产卵量;褐飞虱的卵孵化率随BR处理浓度增高而降低,其浓度为20 mg/L时,褐飞虱的卵孵化率下降了41.8%。5 mg/L BB根吸处理水稻可以显著降低褐飞虱的24 h总产卵量(达100.3粒/株,降低了26.2%)。体外试验结果表明,MeJA和BR处理对褐飞虱卵孵化率无明显影响,说明两者对褐飞虱卵无直接毒害作用。【结论】化合物茉莉酸甲酯、油菜素内酯和苯甲酸苄酯可以提高水稻对褐飞虱的抗性,其中茉莉酸甲酯和油菜素内酯具有化学激发子的作用。     

Differential responses of populations of the copepod Acartia hudsonica to toxic and nutritionally insufficient food algae

Nutritional insufficiency and toxicity are deleterious effects of phytoplankton on grazers. We hypothesize that toxic food is likely to have stronger evolutionary selective effects on grazers than nutritionally insufficient food. We explore this hypothesis in comparative studies of egg production and egg hatching of the copepod Acartia hudsonica challenged with both a toxic and a nutritionally insufficient alga. Experiments lasting 6 days, in which mixtures of different proportions of the suspect and a control alga were offered as food to female copepods, showed that the dinoflagellate Alexandrium fundyense, which bears paralytic shellfish toxins, was toxic to A. hudsonica. In contrast, the diatom Phaeodactylum tricornutum was nutritionally insufficient to A. hudsonica. In another set of experiments, the effects of A. fundyense and P. tricornutum, respectively, as sole foods on egg production and egg hatching success of two geographically separated populations (Maine and Connecticut) of the copepod A. hudsonica were examined in common-environment experiments, after being raised under identical conditions for two generations. The location in Maine regularly experiences toxic blooms of Alexandrium sp. whereas the location in Connecticut does not. During a 6-day period, A. fundyense reduced the egg production rates of the Connecticut copepod population, but not of the Maine population. In contrast, the diatom P. tricornutum reduced the egg production of both populations. These results of this study are consistent with the hypothesis of local adaptation to toxic food, but not to nutritionally insufficient food.     

Effect ofCalotropis latex on laticifers differentiation in callus cultures ofCalotropis procera

Laticifers differentiation in callus cultures of Calotropis procera (Asclepiadaceae) as affected by own latex and its fractions incorporated in Murashige and Skoog (MS) medium is described. Callus cultures have been maintained on MS medium with 2.3 ΜM 6-furfurylaminopurine (FAP) and 3.0 ΜM 1-naphthylacetic acid (NAA). Marked increase in laticifers differentiation (from 10.1 to 28.4 %) was observed on this medium supplemented with 1 % (v/v) of latex. Latex fractions containing proteins + complex polysaccharides or inorganic salts also increased laticifers differentiation (by 21.8 % and 24.1 %, respectively). Other fractions (free amino acid + saccharides, phenols and terpenes + sterols) had no marked effect on laticifers differentiation while alkaloid fraction inhibited it. Effect of latex on laticifers differentiation was much more profound than the reported optimal concentration of plant growth regulators (4.6 ΜM FAP + 1 ΜM IAA). This research was supported by grant-in-aid for research from the University Grants Commission (No. F3-65/91SR II), New Delhi, to Dr. KG. Ramawat.     

Population quality,dispersal and numerical change in the gypsy moth,Lymantria dispar (L.)

Summary First instars from small and large gypsy moth eggs differ significantly in their head capsule width, weight, hatching time and the length of thoracic setae. Pupal weight and the developmental period of immature stages of the gypsy moth originating from small or large eggs do not differ significantly. The mean number of eggs per mass produced by females originating from small eggs is greater than that of females from large eggs although not statistically significant. Highly significant differences in mean egg size of egg masses of each type of female were also observed. The relationship between egg size and dispersal strategies are discussed.Paper No. 2229 Massachusetts Agricultural Experiment Station. University of Massachusetts at Amherst. This research supported (in part) from Experiment Station Project No. 355     

稻虱红单节螯蜂寄生不同虫龄白背飞虱对二者发育表现的影响

【目的】为了解稻虱红单节螯蜂Haplogonatopus apicalis与白背飞虱Sogatella furcifera间的互作关系,开展了稻虱红单节螯蜂在白背飞虱不同龄期寄生时,对寄主及其自身发育表现影响的研究。【方法】在室内25℃条件下,观察了被寄生的白背飞虱各龄若虫及其寄生蜂稻虱红单节螯蜂的发育表现。【结果】白背飞虱2, 3, 4和5龄若虫被寄生后,当龄及其后各龄的历期均显著延长;2和3龄若虫被寄生后,成虫羽化率仅分别为54.29%和60.95%,显著低于在4和5龄若虫被寄生后的成虫羽化率（分别为96.20%和100%）。稻虱红单节螯蜂寄生白背飞虱5龄若虫后的发育历期（23.77 d）显著短于寄生2龄若虫后的发育历期（27.77 d）;寄生3龄若虫的成蜂羽化率最高,为56.19%;而寄生5龄若虫的羽化雄蜂比例最高,为77.12%。【结论】稻虱红单节螯蜂寄生可使白背飞虱若虫发育历期显著延长,白背飞虱2和3龄若虫是稻虱红单节螯蜂发育的适宜寄主。     

Histamine mediates the pro-inflammatory effect of latex of Calotropis procera in rats

INTRODUCTiON: Calotropis procera is known to produce contact dermatitis and the latex of this plant produces intense inflammation when injected locally. However, the precise mode of its pro-inflammatory effect is not known. In present study we have pharmacologically characterized the inflammation induced by latex of C. procera in a rat paw edema model and determined the role of histamine in latex-induced inflammation. METHODS: Inflammation was induced in the hind paw of rats by injecting different doses of dried latex (DL) of C. procera. The inhibitory effect of phenylbutazone, dexamethasone, celecoxib, cyproheptadine, chlorpheniramine and compound 48/80 on edema volume was evaluated and compared with that against carrageenan. The histamine content of DL was measured fluorometrically. RESULTS: DL produced dose-dependent inflammation of the rat paw. Cyproheptadine and chlorpheniramine effectively inhibited DL-induced inflammation (90%; p < 0.01), while anti-inflammatory drugs phenylbutazone, dexamethasone and celecoxib were more effective against carrageenan-induced inflammation. Depletion of mast cell histamine by compound 48/80 produced a significant decrease in DL-induced inflammation as compared with carrageenan (500% versus 25%). DL was also found to contain about 6 microg/g of histamine. CONCLUSIONS: Thus, our study shows that the biogenic amines play a significant role in C. procera latex-induced inflammation and antihistaminic drugs could be effectively used to inhibit inflammatory response elicited by exposure to latex.     

Developmental strategies in Ectobius pallidus (Dictyoptera: Blattidae)

Ectobius pallidus has a semivoltine life cycle, overwintering as an egg and intermediate nymphal instar. A range of instars may overwinter, although the exact composition of an overwintering population varies annually. A number of developmental pathways are defined, involving both quiescence and diapause. The proportion of an instar following each pathway also varies annually. In ‘advanced’ years more 3rd and 4th instars enter diapause. The ecological significance of the different developmental strategies is discussed.     

Biological effects of alkaloïds extracted from three plants of Moroccan arid areas on the desert locust

Abstract. The effects of three plant species, Calotropis procera , Zygophyllum gaetulum and Peganum harmala on survival, feeding behaviour and reproduction in the desert locust ( Schistocerca gregaria ) were studied under laboratory conditions. The species originate in Moroccan arid areas and were seen to be avoided by locusts during the 1995 upsurge in Morocco. Alkaloids were extracted from leaves of the plants and applied topically to lettuce for leaves which were then offered with no other food to young adults of the desert locust for 3 days. The locust were then fed on untreated lettuce for 15 days. Controls were fed with lettuce leaves treated with ethanol. The results indicate that the alkaloids extracted from each of the three plant species cause a significant mortality compared to untreated controls and reduced food intake, as well as causing weight loss. Alkaloids extracted from C. procera and Z. gaetulum prevent sexual maturity both in males and females. However, alkaloids extracted from P. harmala merely delay sexual maturity by at least 8 days and engender a reduction in female fecundity and hatching rate compared to untreated controls. The presence and the concentration of alkaloids and other secondary substances in the investigated plants may explain the avoidance behaviour manifested by locusts under natural conditions.     

The effect of superparasitism on development of the solitary parasitoid wasp, Venturia canescens (Hymenoptera: Ichneumonidae)

Abstract.

• 1 The effects of superparasitism on the rate of development, adult size and mortality of Venturia canescens (Hymenoptera: Ichneumonidae) were investigated. Parasitoids were reared from third (L3) and fifth (L5) instars of one of its hosts, Plodia interpunctella (Lepidoptera: Pyralidae) containing one, two or four parasitoid eggs.
• 2 Superparasitism increased the development time of Venturia reared from both instars, but the developmental delay was more evident in wasps from L5 hosts.
• 3 The size of parasitoids from L3 hosts was unaffected by egg number, but wasps from both superparasitized L5 treatments were significantly smaller than those from singly parasitized hosts.
• 4 Parasitoid mortality was significantly higher in L5 than L3, but within instars did not differ significantly with egg number.
• 5 The results confirm that superparasitism may affect the fitness of both the adult female wasp and her progeny, and should therefore be incorporated into models of superparasitism as an adaptive foraging strategy.