PHOTOPERIODIC CONTROL OF ADULT DIAPAUSE IN CHRYSOPERLA SINICA （TJEDER） （NEUROPTERA： CHRYSOPIDAE） -I. CRITICAL PHOTOPERIOD AND SENSITIVE STAGES OF ADULT DIAPAUSE INDUCTION

Photoperiodic sensitivity for diapause induction of the green lacewing, Chrysoperla sinica (Tjeder) was examined at 22℃. The adult diapause of C. sinica was induced by short-day photoperiods, and the critical photoperiod for its induction was between 12.5L-11.5D and 13L-11D.Adults developed without diapause under long-day conditions, and entered diapause under short-day conditions. The adult stage was the uppermost sensitive stage for adult diapause induction, adults could go into diapause only when the emerging adults were under diapause-inducing short-day photoperiods. The short-day photoperiodic experience by transferring between 15L: 9D and 9L: 15D at preimaginal stages did not result in adult diapause under 15L: 9D photo regime, although some treatments extended the pre-oviposition period in adult stage. The results showed that the 3rd instar larvae and pre-pupae were more sensitive to the photoperiodic change from 15L: 9D to 9L: 15D photo regime than the other preimaginal stages.     

Effects of photoperiod and temperature on diapause induction in Conogethes punctiferalis （Lepidoptera： Pyralidae）

The yellow peach moth, Conogethes punctiferalis （Guenee）, a multivoltine species that overwinters as diapausing larvae, is one of the most serious insect pests on maize in China. Effect of photoperiod and temperature on larval diapause was examined under empirical laboratory conditions. Short-day treatments caused larval diapause at 25℃, and the critical photoperiod was between 12 and 13 h （or 12 h 51 min） light per day. No sensitive instar was identified for diapause induction under alternated short- （L ： D 11 ： 13 h） and long-day （L ： D 14 ： 10 h） treatments at different larval stages. However, accumulative treatment of three instars and 10 d under short-day treatment was required for the induction of 50% larval diapause. All larvae entered diapause at 20℃, whereas less than 3% did so at 30℃, irrespective of the long- or short-day treatment. Furthermore, under the short-day treatment, more than 90% of larvae went into diapause with temperatures ≤ 25℃, but less than 17% did so at 28℃. In contrast, under the long-day treatment, less than 19% of larvae went into diapause with temperatures ≥23 ℃. The forward shift （5℃） of critical temperature under the long-day regime demonstrated the compensatory effect of temperature and photoperiod on diapause induction. In conclusion, C. punctiferalis had a temperature-dependent type Ⅰ photoperiodic diapause response; there was no sensitive instar for diapause determination, but the photoperiodic accumulation time countermeasures both of the short-day cycles and the number ofinstars exposed, and the photoperiodic diapause response, was a temperature-compensated phenomenon.     

Repellent effects of pongam oil on settlement and oviposition of the common greenhouse whitefly Trialeurodes vaporariorum on chrysanthemum

The repellent activities, including host deterrence and anti-oviposion, of pongam oil against the adults of the common greenhouse whitefly Trialeurodes vaporariorum Westwood in greenhouses were tested. Chrysanthemum plants treated with different concentrations （0.5%-2.0%） of water-suspended pongam oil showed relatively long-lasting host deterrent and anti-oviposition effects on the adults of greenhouse whitefly. Although the repellent effect declined in time and concentration, strong effects on the reduction of oviposition were found, which lasts, dependent on concentration at least 12 days after application.     

Effect of pine foliage damage on the incidence of larval diapause in the pine caterpillar Dendrolimus punctatus （Lepidoptera： Lasiocampidae）

The pine caterpillar Dendrolimus punctatus （Walker） with a larval facultative diapause is one of the most destructive insect pests of the pine tree Pinus massoniana in China. The larvae feeding on pine trees with different damage levels were studied to determine the induction of diapause under both laboratory and field conditions. Developmental duration of larvae before the third instar was the longest when fed with 75%-90% damaged needles, followed by 25%-40% damaged needles and intact pine needles, whereas mortalities did not differ among different treatments under the conditions of 25℃ and critical photoperiod 13.5：10.5 L：D. At 25 ℃, no diapause was induced under 15：9 L：D, whereas 100% diapause occurred under 12：12 L：D regardless of the levels of needle damage. Incidences of larvae entering diapause when they were fed with intact, 25%-40% and 75%- 90% damaged pine needles were 51.7%, 70.8% and 81% under 13.5：10.5 L：D, respectively. Similar results were obtained in the field experiment. Incidence of diapause was significantly different among the pine needle damage levels of pine trees when the photoperiod was close to the critical day length, indicating that the effect of host plants on diapause induction was dependent on the range of photoperiod. The content of amino acid and sugar decreased and tannin increased in pine needles after feeding by the pine caterpillars, suggesting that changed levels of nutrients in damaged needles or a particular substance emitted by damaged pine trees was perhaps involved in the diapause induction of the pine caterpillar.     

How does the host-specialized aphid deal with food deficiency？

Aphis gossypii Glover shows obvious host specialization, with cucurbit- and cotton-specialized biotypes or host races in many regions. Because its annual natal hostcrops senesce earlier the cucurbit-specialized biotype may suffer food deficiency. The method this biotype uses to overcome this challenge is still poorly understood. In orderto understand the potential of the cucurbit-specialized biotype aphids in host shift and usage, the performance of this biotype on cotton （Gossypium hirsutum）, a common butpoor quality host plant, was explored in this study. The cucurbit-specialized aphids could establish populations on cotton only when these plants had at least nine leaves, and subsequent populations developed rather slowly. The presence of whitefly populations on cotton improved the success rate of cucurbit-specialized aphids. The cucurbit-specialized aphidswere mainly distributed on the older leaves of cotton, with only a few settling on the upper leaves. The cucurbit-specialized aphids reared on cotton for 40, 54 and 61 days stillmaintained strong preference for their natal host plant, cucumber （Cucumis sativus）, rather than cotton, and their net reproductive rates and intrinsic rates of natural increase weredramatically lower when they were transferred onto new six-leaf cotton plants or detached leaves. Therefore, we concluded that the cucurbit-specialized aphids have the potentialto utilize mature or whitefly-stressed cotton plants, but that this feeding experience on cotton did not alter their specialization for cucurbits. Some cotton plants could act as atemporary host for the cucurbit-specialized aphids to overcome food deficiency arising from senescing cucurbits.     

Effects of nitrogen on the tolerance of brown planthopper, Nilaparvata Lugens, to adverse environmental factors

The effect of nitrogen content in rice plants on the tolerance of brown planthopper (BPH), Nilaparvata lugens Stal to high temperature, starvation and insecticide, was studied in the laboratory at International Rice Research Institute (IRRI), Philippines. Survival of nymphs and adults, fecundity and egg hatchability were significantly increased by the increase of nitrogen content in host plants at 38℃. Moreover, the survival of nymphs,fecundity and egg hatchability were significantly higher in BPH populations on rice plants with a high nitrogen regimen than those on rice plants with a low nitrogen regimen.Meanwhile, the tolerance of female adults to starvation and nymphs to growth regulator buprofezin on rice plants with a high nitrogen regimen were slightly increased. This indicates that the tolerances of BPH to adverse environmental stresses were positively increased by the application of nitrogenous fertilizer. The outbreak potential of BPH induced by the excessive application of fertilizer in rice fields was also discussed.     

Response of Solanum tuberosum to Myzus persicae infestation at different stages of foliage maturity

Young leaves of the potato Solanum tuberosum L. cultivar Kardal contain resistance factors to the green peach aphid Myzuspersicae （Sulzer） （Hemiptera： Aphididae） and normal probing behavior is impeded. However, M. persicae can survive and reproduce on mature and senescent leaves of the cv. Kardal plant without problems. We compared the settling ofM. persicae on young and old leaves and analyzed the impact of aphids settling on the plant in terms of gene expression. Settling, as measured by aphid numbers staying on young or old leaves, showed that after 21 h significantly fewer aphids were found on the young leaves. At earlier time points there were no difference between young and old leaves, suggesting that the young leaf resistance factors are not located at the surface level but deeper in the tissue. Gene expression was measured in plants at 96 h postinfestation, which is at a late stage in the interaction and in compatible interactions this is long enough for host plant acceptance to occur. In old leaves of cv. Kardal （compatible interaction）, M. persicae infestation elicited a higher number of differentially regulated genes than in young leaves. The plant response to aphid infestation included a larger number of genes induced than repressed, and the proportion of induced versus repressed genes was larger in young than in old leaves. Several genes changing expression seem to be involved in changing the metabolic state of the leaf from source to sink.     

Effects of crop development on the emission of volatiles in leaves of Lycopersicon esculentum and its inhibitory activity to Botrytis cinerea and Fusarium oxysporum

Volatiles emitted from the leaves of Lycopersicon esculentum at the two-, ten-leaf and anthesis periods were collected by a gas absorbing method and analyzed by gas chromatography （GC）-mass spectrometry. In total, 33 compounds of volaUles emitted from three developmental stage plants were separated and identified, and quantitatively analyzed by the internal standard addition method. All of the samples of volatile were found to be rich in monoterpenes and sesquiterpenes.β-phellandrene and caryophyllene predominated in the volatiles of the leaves of plants at the two- and ten-leaf stages. Furthermore, （E）-2-hexenal were the dominant components in the volatiles emitted from anthesis plants. The results of volatiles analyzed show that the compositions varied depending on the developmental stages. The volatiles emitted from crushed tomato leaves of plants at the anthesis stage had the most strongly inhibitory activity against the spore germination and hyphal growth of Botrytis cinerea and Fusarium oxysporum, followed by ten- and two-leaf plants. However, the activity of volatiles, emitted from the leaves of plants at the two-leaf stage, in inhibiting F. oxysporum was greater than B. cinerea.     

Influence of rice black streaked dwarf virus on the ecological fitness of non-vector planthopper Nilaparvata lugens （Hemiptera： Delphacidae）

Rice black streak dwarf virus （RBSDV） is transmitted by the small brown planthopper （SBPH）, Laodelphax striatellus （Fallen）. Non-vector rice brown planthopper （BPH）, Nilaparvata lugens （Stal）, shares the same host rice plants with SBPH in paddy fields. The changes in nutritional composition of rice plants infected by RBSDV and the ecological fitness of BPH feeding on the infected plants were studied under both artificial climate chamber and field conditions. Contents of 16 detected amino acids and soluble sugar in RBSDV infected rice plants were higher than those in the healthy ones. On the diseased plants BPH had significantly higher nymphal survival rates, nymphal duration of the males, weight of the female adults, as well as egg hatchability compared to BPH being fed on healthy plants. However, there was no obvious difference in female nymph duration, longevity and fecundity. Defense enzymes （superoxidase dismutase, SOD and catalase, CAT） and detoxifying enzymes （carboxylesterase, CAE and glutathione S-transferase, GST） in BPH adults fed on diseased plants had markedly higher activities. The results indicate rice plants infected by RBSDV improved the ecological fitness of the brown planthopper, a serious pest but not a transmitter of the RBSDV virus.     

PHOTOPERIODIC CONTROL OF ADULT DIAPAUSE IN CHRYSOPERLA SINICA (TJEDER) (NEUROPTERA: CHRYSOPIDAE— I. CRITICAL PHOTOPERIOD AND SENSITIVE STAGES OF ADULT DIAPAUSE INDUCTION

Abstract  Photoperiodic sensitivity for diapause induction of the green lacewing, Chrysoperla sinica (Tjeder) was examined at 22°C. The adult diapause of C. sinica was induced by short-day photoperiods, and the critical photoperiod for its induction was between 12.5L-11.5D and 13L-11D.
Adults developed without diapause under long-day conditions, and entered diapause under short-day conditions. The adult stage was the uppermost sensitive stage for adult diapause induction, adults could go into diapause only when the emerging adults were under diapause-inducing short-day photoperiods. The short-day photoperiodic experience by transferring between 15L: 9D and 9L: 15D at preimaginal stages did not result in adult diapause under 15L: 9D photo regime, although some treatments extended the pre-oviposition period in adult stage. The results showed that the 3rd instar larvae and pre-pupae were more sensitive to the photoperiodic change from 15L: 9D to 9L: 15D photo regime than the other preimaginal stages.     

Inheritance of the photoperiodic response controlling imaginal summer diapause in the cabbage beetle, Colaphellus bowringi

Adults of the cabbage beetle Colaphellus bowringi display a summer diapause in response to the exposure of their larvae to long photoperiods. In the present study, the inheritance of the photoperiodic response controlling summer diapause in C. bowringi by crossing a high diapause strain (D strain) with a laboratory selected nondiapause strain (N strain) was investigated under different photoperiods at 22, 25 and 28 °C. The beetles in both reciprocal crosses and backcrosses showed a clear short-day response for the induction of diapause at all temperatures, similar to that of the D strain, suggesting that photoperiodic response of this beetle is heritable. The diapause incidences in the progeny from all the crosses under LD 15:9 or LD 12:12 at 25 °C suggest that genetic and genetic-environmental interactions are involved in diapause induction. The incidence of diapauses in F₁ progeny was significantly lower than that in the D × D strain but significantly higher than that in the N × N strain, indicating that the diapause capability is inherited in an incomplete dominant manner. The incidence of diapause was greater among the offspring of hybrid females when those females had a D strain mother or grandmother rather than a N strain mother or grandmother, indicating that maternal effects on diapause induction are stronger than paternal effects. The laboratory selected nondiapause strain also showed a short-day photoperiodic response at a low temperature of 22 °C, indicating that the photoperiodic photoreceptor and photoperiodic clock still function in the nondiapause strain.     

Diapause in a Glasgow strain of the flour moth, Ephestia kuehniella

ABSTRACT. The incidence of diapause in Ephestia kuehniella Zeller from an unhealed granary in Scotland was influenced by both photoperiod and temperature. At 25°C, nearly 50% of larvae entered diapause when reared in continuous darkness (DD) and up to 30% did so in short photoperiods. Little diapause was detected around LD 14:10 but a second, smaller peak of about 20% occurred at LD 16:8 and LD 18:6, falling away again to nearly zero in continuous light. More larvae entered diapause when reared continuously at 15 or 20°C than at 25 and 30°C. However, when larvae reared from hatch at 25°C in LD 16:8 were transferred after 1 week to 15°C in LD 9:15, almost twice as many entered diapause as did those reared at 15°C throughout. The sensitive phase for diapause induction occurred near the start of the final instar. The mean duration of diapause was between 2 and 3 months in most photoperiods at 20 and 25°C, and was shorter at 15°C. However, in DD at 25°C, it lasted about 7 months. Termination of diapause was hastened in larvae reared at 25°C in DD by transferring them to LD 14:10, and also by chilling them at 7.5°C for 6 weeks before returning to 25°C in DD. In an unhealed store in southern England, viable adults emerged from May to July and originated from larvae which terminated diapause relatively late. It would appear from the results of transferring larvae back to the laboratory at various times during the winter that some phases of diapause development were completed quite early after exposure to low temperatures, although no further development took place in the store until temperatures rose again in April.     

Environmental and genetic control of the larval diapause of the Southwestern corn borer, Diatraea grandiosella

ABSTRACT. The interaction of photoperiod and temperature in the regulation of the induction and termination of the larval diapause of the Southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera), was examined. A population originating from south-eastern Missouri had critical daylengths for diapause induction of about 15h 5min (ecological threshold) and llh (physiological threshold). The ecological threshold was more stable than was the physiological threshold at temperatures lower than 25°C. Above 25°C the diapause response was suppressed. The insect appears to measure photoperiods in a stationary manner since a stepwise increase or decrease in photoperiod did not affect the incidence of diapause. In the critical region of the photoperiodic response curve, a higher incidence of diapause was found among females than among males. Females entered diapause later than did males, but resumed active development earlier than males. The rate of diapause development was more temperature dependent than was the rate of diapause induction, yet it was also clearly under photoperiodic control. The temperature coefficient (Q₁₀) for this process was about 4. Several other factors including sex-linkage, age, and geographic adaptations are involved in controlling the rate of diapause development, even more so than they are in controlling diapause induction. In the laboratory, the intensity of diapause declined gradually without larvae being exposed to non-diapause inducing conditions. Incubation of field-collected larvae revealed that their sensitivity to diapause maintaining photoperiods had ended by January. Three generations of selection of a Mississippi population of D. grandiosella at 30°C and LD 12:12 led to the production of an essentially diapause-free strain and a diapause strain.     

Effects of photoperiod and temperature on the development and diapause of the bark beetle Ips typographus

Abstract:  Diapause was induced in a Central European population of Ips typographus grown at 20°C when the day length decreased below 16 h [50% diapause incidence occurred in the 14.7:9.3 h L:D (light:dark) regime]. The non-diapausing adults fed on days 2–6 and 10–14 after the ecdysis and swarmed after the second feeding bout with chorionated eggs in the ovaries and sperm in the spermiducts. Neither gonads nor the flight muscles matured and no swarming occurred in the diapausing adults. The development from egg to adult took about 34 days in both 18:6 h (no diapause) and 12:12 h L:D (diapause) regimes, but it was extended by up to 30% without diapause induction when only larvae or pupae were exposed to L:D 12:12 h. Diapause was induced in insects reared at L:D 12:12 h through the last larval and the pupal instars and/or in the adult stage. Temperature ≥ 23°C prevented diapause induction at L:D 12:12 h but diapause occurred at L:D 14:10 h associated with 26:6°C thermoperiod. The effect of thermoperiods on the developmental rate requires further research. Exposure of the non-diapausing adults to 5°C for several days blocked feeding and evoked a diapause-like state, whereas diapausing adults fed and their gonads slowly developed at this temperature. Diapausing adults exposed in forest to low night temperatures and transferred in October to 20°C readily reproduced at 18:6, but not 12:12 h L:D photoperiods. After 2-months at 5°C and darkness, they became insensitive to the photoperiod, matured and most of them also swarmed at 20°C in the 12:12 h L:D regime. In a Scandinavian population, diapause occurred at 18:6 h L:D and was terminated either by exposure to 5°C or by very long photoperiod (L:D 20:4 h) combined with high temperature (23°C).     

Performance of cabbage stem flea beetle larvae (Psylliodes chrysocephala) in brassicaceous plants and the effect of glucosinolate profiles

The cabbage stem flea beetle (CSFB), Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae), is one of the most important pests in European winter oilseed rape production. Adult beetles feed on young leaves whereas larvae mine within the petioles and stems. Larval infestation can cause significant crop damage. In this study, the host quality for CSFB of four oilseed rape (Brassica napus L.) cultivars and seven other brassicaceous species with different glucosinolate (GSL) profiles was assessed under controlled conditions. Larval instar weights and mortality were measured after 14 and 21 days of feeding in the petioles of test plants. To study the impact of GSL on the performance of larvae, the GSL contents in petioles from non-infested and infested plants were analysed before, and 21 days after, the start of larval infestation. Larval performance was not significantly different between the four cultivars of oilseed rape, but differed considerably among the other brassicaceous species tested. In comparison to the weight of larvae in the standard B. napus cv. Robust, the larval weight was higher in turnip rape (Brassica rapa L. var. silvestris) and significantly reduced in white mustard (Sinapis alba L.), oil radish (Raphanus sativa L. var. oleiformis), and cabbage (Brassica oleracea L. convar. capitata var. alba). The duration of larval development increased in white mustard and oilseed radish. The GSL profiles of the petioles showed little difference between non-infested and infested plants of oilseed rape whereas the content of aliphatic GSL increased in the infested turnip rape plants. In contrast, the aliphatic and benzenic GSL decreased in infested Indian rape (B. rapa subsp. dichotoma Roxb.). Larval weight was not correlated with the total GSL content of plants, neither before infestation nor 21 days after. Larval weight was positively correlated with progoitrin and 4-hydroxyglucobrassicin. White mustard, which provides inferior host quality for larval development, has the potential to introduce insect resistance into high-yielding oilseed rape cultivars in breeding programmes.     

Photoperiodic induction of the pupal diapause in the tobacco hornworm, Manduca sexta

A study was made of photoperiodic induction of the facultative pupal diapause in the tobacco hornworm, Manduca sexta, reared on artificial diet in the laboratory. The species entered a prolonged diapause when the egg and larval feeding stages were reared in daily photoperiods of 13·5 hr or less. Diapause was induced in all insects at photoperiods ranging from 1 to 13 hr, and part of the population entered diapause at only 15 to 30 min of light per day. Photoperiods of 14 hr or more and continous darkness prevented diapause. Duration of diapause varied with the inductive photoperiod in which the hornworms were reared during the sensitive period. Insects reared in longer diapause-inducing photoperiods within a range of 12 to 13·25 hr remained in diapause longer than those reared in shorter photoperiods. There was no difference in the rate of larval development of hornworms reared in diapause-inducing vs diapause-preventing photoperiods. Temperatures of 26 to 30°C were most favourable for the photoperiodic induction of diapause; at 21°C, the critical photoperiod and incidence of diapause were decreased. Diapause induction was suppressed by low (18°C) and higher (33°C) temperatures. The number of inductive 12L:12D (light = 12 hr; dark = 12 hr) cycles required to induce diapause ranged from as few as 5 for some insects to as many as 12 for others when the post-inductive régimen was continuous light, but with insects previously held in continuous dark, as few as 2 12L:12D cycles during the last 2 days of larval feeding induced diapause in 38 per cent of the population. Only 3 to 4 cycles of 15L:9D during the final larval instar reversed inductive effects of 14 to 15 12L:12D cycles. Photoperiodic sensitivity extended from the late embryo to the end of larval feeding but showed considerable fluctuation during development with maximum sensitivity occurring just before egg hatch and during larval growth.Light breaks applied at different times during the dark period of 12L:12D cycles generated different response curves, depending on the number of cycles in which light breaks were repeated. When repeated for 6 cycles, a unimodal response curve was obtained; 10 cycles produced a bimodal curve and light breaks given for 18 cycles throughout the sensitive period averted diapause regardless of time of night applied. It is suggested that diapause is regulated by a photo- and thermolabile substance that accumulates during long nights (11 hr or more) and acts during the early pupal stage to inhibit the translocation and release of development-promoting neurosecretion from the brain.     

大猿叶虫哈尔滨种群的滞育诱导研究

本文研究了光周期、温度和食料对大猿叶虫Colaphellus bowringi Baly哈尔滨种群滞育诱导的影响。结果表明,在恒温20～30℃范围内,大猿叶虫哈尔滨种群滞育率为91.8%～100%,未见明显的光周期诱导反应,但温度对其滞育诱导具有一定的作用,高温可使少部分大猿叶虫继续发育而不滞育。在平均25℃的温周期与光周期L12∶D12条件下,其滞育诱导差异不显著。大猿叶虫取食白菜、油菜、雪里蕻、萝卜和独荇菜5种食料,在25℃滞育率为89.5%～100%;在28℃滞育率为76.9%～100%,食料种类对大猿叶虫哈尔滨种群滞育诱导差异显著,其中,取食独荇菜滞育率最低,取食萝卜滞育率最高。     

The role of photoperiod and temperature in determination of summer and winter diapause in the cabbage beetle,Colaphellus bowringi (Coleoptera: Chrysomelidae)

The cabbage beetle, Colaphellus bowringi, is a short-day species undergoing an imaginal summer and winter diapause. Its photoperiodic response highly depends on temperature. All adults entered diapause at ≤ 20 °C regardless of photoperiods. High temperatures strongly weakened the diapause-inducing effects of long daylengths. The diapause-averting influence of short daylengths was expressed only at high temperatures (above 20 °C). This indicates that the beetle has a cryptic ability to reproduce in summer. In fact, summer and winter diapause were induced principally by relatively low temperatures in the field, whereas photoperiod had less influence on diapause induction. The critical daylength for the autumnal population was between 12 h and 13 h. By transferring from a long day to a short day or vice versa at different times after hatching, it was shown that the sensitive stage with regard to photoperiod was the larva, whereas a long day was photoperiodically more potent than a short day. The sensitive stage to temperature encompassed the larval, pupal and adult stages. This different response pattern serves to ensure that the beetle enters summer and winter diapause in time. The selections for non-diapause trait under laboratory (at 25 °C) and natural conditions (at >24 °C) showed that the beetle could lose its sensitivity to photoperiod very rapidly.     

Temporal changes in olfactory and oviposition responses of the diamondback moth to herbivore‐induced host plants

Temporal changes in the pre‐ and post‐alighting responses of mated female diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), to two species of Brassica (Brassicaceae) host plants induced by larval feeding were studied using olfactometer and oviposition assays. Females displayed strong olfactory and oviposition preferences for herbivore‐induced common cabbage (Brassica oleracea var. capitata L. cv. sugarloaf) plants over intact plants; these preferences decreased with time and disappeared by the 7th day after induction. In herbivore‐induced common cabbage plants, eggs were clustered near feeding damage on the younger leaves (leaves 5–7), whereas in intact plants, eggs were clustered on the stem and lower leaves (leaves 1–4) . However, as the time interval between larval feeding and oviposition increased, more eggs were laid on the lower leaves of induced plants. This demonstrates a change in egg distribution from the pattern associated with induced plants to that associated with intact plants. In contrast, females displayed strong olfactory and oviposition preferences for intact Chinese cabbage [Brassica rapa ssp. pekinensis (Lour.) Hanelt cv. Wombok] plants over induced plants; these preferences decreased with time and disappeared by the 5th day after induction. More eggs were laid on the upper leaves (leaves 4–6) than on the lower leaves (leaves 1–3) of intact Chinese cabbage plants at first, but the distribution changed over time until there were no significant differences in the egg count between upper and lower leaves by the 4th day post induction. For both host plant species, pre‐alighting responses of moths were reliable indicators of post‐alighting responses on the first 2 days post induction. The results suggest that temporal changes in a plant's profile (chemical or otherwise) following herbivory may influence attractiveness to an insect herbivore and be accompanied by changes in olfactory and oviposition preferences.