Effects of plant nutrient availability and host plant species on the performance of two Pieris butterflies (Lepidoptera: Pieridae)

We assayed the interaction on the availability of plant nutrient and species of host plant on the performance of two species of Pieris butterfly. The results indicated that constant application of different levels of fertilizers to the four different host plants resulted to an increase in their content of plant nutrients. The chemical analysis showed that the added nutrients increased foliar nitrogen and water contents, but there was no effect on the level of glucosinolates. Larvae that fed on highly-nutritious foliage increased their growth rates and showed a shorter development period. The results of feeding trials revealed that the 4th-instar larvae, which had fed on host plants with higher levels of fertilization had a shorter duration of development, less consumption rate, higher growth rate and food processing efficiency. To summarize, this research revealed that both the availability of plant nutrient and species of host plant can strongly influence the physiology and foliar chemistry of host plants. Moreover, the changes of phytochemical in the host plants may play an important role in affecting the performance (growth and food utilization efficiency) of both species of Pieris butterflies.     

The potential role of ectomycorrhizal fungi in determining Douglas-fir resistance to defoliation by the western spruce budworm (Lepidoptera: Tortricidae)

There is phenotypic variation among individual trees of interior Douglas-fir (Pseudotsuga menziesii var. glauca [Beissn.] Franco) in their resistance to defoliation by the western spruce budworm (Choristoneura occidentalis Freeman). We evaluated the potential role of ectomycorrhizal fungi in determining this resistance using half-sib seedlings derived from parent trees that are resistant versus susceptible to budworm defoliation in the field. The seedlings were inoculated with Laccaria bicolor ectomycorrhizal fungi, fertilized, or untreated. Approximately 48 d after treatment, late-instar larvae from a nondiapausing laboratory colony of C. occidentalis were allowed to feed on pairs of resistant versus susceptible seedlings for 1 wk. Chemical analyses of current-year shoots for nitrogen (N), phosphorus (P), magnesium (Mg), and zinc (Zn) indicated that the fungus increased foliar concentrations of P and Mg in resistant seedlings, but it did not increase their growth rate. However, L. bicolor had no effect on foliar concentrations of P or Mg in susceptible seedlings, even though seedling growth rates increased slightly in response to the inoculation. L. bicolor had no effect on foliar levels of N or Zn in any of the seedlings. As expected, fertilization increased levels of N and P in the foliage of both resistant and susceptible seedlings, but it did not affect levels of Mg and Zn. Surprisingly, the fertilizer treatment had no effect on seedling growth rates. Despite these differences, late-instar budworms showed no feeding preference among untreated, mycorrhizal, or fertilized seedlings. The fact that seedlings from resistant versus susceptible Douglas-firs responded differently to the L. bicolor treatment lends preliminary support to the hypothesis that ecotmycorrhizae might play a role in Douglas-fir resistance to damage from the western spruce budworm. Finally, differences in foliar concentrations of N and P among untreated seedlings from different maternal trees suggested that foliar nutritional chemistry is influenced by the tree's genotype.     

Enhancement of nitrogen fixation in lentil,faba bean,and soybean by dual inoculation with Rhizobia and mycorrhizae

The combined effect of Vesicular Arbuscular Mycorrhizae (VAM) and Rhizobium on the cold season legumes, lentil and faba bean, as well as on summer legume, soybean, were studied in soils with low indeginous VA mycorrhizal spores. Inoculation of the plant with VA mycorrhizal fungi increased the level of mycorrhizal root infection of lentil, faba bean and soybean. The inoculation with Rhizobium had no significant effect on VA mycorrhizal infection percent, but VA mycorrhizal inoculation increased nodulation of the three legumes. The inoculation with Rhizobium alone significantly increased plant dry weight and N content of lentil and faba bean as well as seed yield of soybean. VA mycorrhizal inoculation also significantly increased plant dry weight and phosphorus content of the plants as did fertilization with superphosphate. Rock phosphate fertilization, however, had no significant effect on plant growth or phosphorus uptake. The addition of rock phosphate in combination with VA mycorrhizal inoculation significantly increased plant dry weight and P uptake of the plants. The dual inoculation with both rhizobia and mycorrhizae induced more significant increases in plant dry weight, N and P content of lentil and faba bean as well as seed yield of soybean than inoculation with either VA mycorrhizae or Rhizobium alone.     

5种叶面肥对草莓光合特性及品质的影响

为探讨不同叶面肥对大棚草莓光合特性、果实品质及产量的影响,并筛选出适宜的叶面肥,以甘肃省兰州市西固区牟家台草莓温室大棚内栽植的草莓品种‘蒙特瑞’为试材,在施肥充足的情况下,在4个生育期追肥喷施经典750倍液（T1）、花仆1500倍液（T2)、润亮750倍液(T3)、艾德拉果500倍液（T4）及磷酸二氢钾1500倍液（T5）5种叶面肥,清水作为对照（CK）,测定了处理植株光合参数、果实品质、生物量及产量等指标。结果表明：（1）喷施不同叶面肥处理后草莓植株生物量、叶绿素含量显著增加,叶片的净光合速率和蒸腾速率显著上升,喷施叶面肥后的草莓植株胞间二氧化碳浓度均高于CK;（2）对果实品质而言,T2和T3处理能够显著改善草莓果形指数,T1和T5可以显著增大果实体积和重量。其中,T1的平均单果重较CK增加了5.89 g,T5的果实横径和纵径分别较CK增加了1.22 cm和1.15 cm。（3）实硬度、可溶性固形物含量、维生素C含量和还原糖含量有很明显的提高,并以T1施用效果最佳,较CK分别增加了3.3%、17.25 mg/g、2.71%。处理T1和T3可溶性蛋白含量分别较CK提高了0.097 mg/g和0.070 mg/g;（4）喷施叶面肥能够显著提高草莓单位面积产量,且以处理T1处理产量最高,较CK增长了13.65%。可见,施用适宜的叶面肥均能有效改善草莓营养生长状况,提升草莓果实品质,显著提高产量,并以经典750倍液叶面肥施用综合效果最佳。     

Some effects of seed source on early growth in Maris Peer potatoes

Potato seed tubers cv. Maris Peer obtained from a number of sources in England and Scotland were graded into a range of weights and after storage for approximately 3 or 7 months in 1971 or 3 months in 1972 they were planted to determine the effect of seed source on early foliage growth. In both years there were large differences between seed sources on the effect of seed tuber weight on the dry weight of foliage produced in a glasshouse from seed stored for 3 months. In some instances small seed from one source produced the same weight of foliage as large seed from another source. In 1971 after seed storage for 7 months there was no effect of source on foliage dry weight produced in the field. There was, however, no consistent effect of the site of production of the parent seed, of fertilizer treatments of the seed crop, or of N content of the seed tubers. Seed tuber N content increased, though not proportionally, with an increase in seed weight. It was unaffected by source except for seed tubers from one site m 1972.     

The effect of VA mycorrhizal fungi,phosphorus and drought stress on the growth of Acacia nilotica and Leucaena leucocephala seedlings

The effect of vesicular-arbuscular mycorrhizal (VAM) fungi on growth and drought resistance of Acacia nilotica and Leucaena leucocephala seedlings was studied in a glasshouse experiment. The experimental design was a 2·2·2 factorial: ± mycorrhizal inoculation, ± application of phosphorus fertilizer and ± repeated drought treatment. The growth promoting effect of VAM fungi equalled the effect of phosphorus fertilization after 12 weeks. The drought treatment reduced seedling biomass and nodulation. Differences between the plant species were found with respect to growth improvements due to VAM inoculation and/or phosphorus fertilization under drought stress conditions. The results are discussed in relation to plant drought resistance and reforestation in the subhumid to arid tropics.     

Soil nutrients and water availability interact to influence willow growth and chemistry but not leaf beetle performance

We investigated the effects of soil nutrient and water availability on the growth and chemistry of the silky willow (Salix sericea Marshall), and on the performance of the imported willow leaf beetle (Plagiodera versicolora Laichartig). Our major aims were to determine whether there are nutrient–water interactions on plant traits and whether this leads to parallel interactions for herbivore performance. We used a 2 × 3 fully factorial design, which consisted of high and low nutrient treatments crossed with dry, field capacity, and flooded water treatments. We found that nutrient additions increased plant growth, but only in field capacity and flooded conditions (nutrient–water interaction). Leaf nitrogen content also depended on the interaction between soil nutrients and water: nutrient addition resulted in a larger increase in foliar nitrogen in the field capacity treatment than in the flooded and dry treatments. Of the two phenolic glycosides measured, salicortin and 2′‐cinnamoylsalicortin, only one was affected by the treatments. 2′‐cinnamoylsalicortin concentration was lower in the high nutrient–dry treatment compared with the other treatments. In contrast to plant responses, there were no interactions found for larval or pupal weight or development time. Nutrient addition led to an increase in female pupal weight, and foliar N was positively correlated with female pupal weight and negatively correlated with female development time. In addition, leaf water was positively correlated with female development time. The lack of interactions for insect performance may stem from the small absolute differences in foliar nitrogen content associated with the interaction between the nutrients and water. Taken together, our results suggest that nutrient–water interactions influence plant traits that are potentially important for insect performance (leaf nitrogen and water), but these interactions do not produce parallel interactions in beetle performance.     

Effect of VA Mycorrhizal Inoculation on Growth of Asparagus Seedlings

Experiments on asparagus (Asparagus of)icinalis L.) inoculated with VA mycorrhizal fungi were conducted under two fluvo-aquatic phosphorus deficient soils. This study was to examine the growth response of VA mycorrhizae and fertilizer effects on the growth of mycorrhizal and non-mycorrhizal asparagus seedlings in pots and under field conditions. Inoculation with VA mycorrhizal fungi significantly increased mycorrhizal infection and enhanced seedling growth. In treatments of fertilization by different batches of NPK or by different amount of application it was shown that phosphorus was most favourable to VAM activity. Both the prevalance of mycorrhizal infection and the dry weight of seedlings in treatment with NPK in 1:0:1 was similar to that in 1:1:1 and 1:2:1 after inoculation. Further more the prevalance of infection, plant growth and P content in the treatment of 1/2 an amount of NPK in 1:1:1 were even higer than those in full amount of NPK and in non-fertilization. It is indicated that phosphorus uptake and plant growth benefit greatly by mycorrhizal inoculation. Mycorrhizal plant requires only about half as much phosphorus to achieve maximum growth as the uninoculated plants.     

AM fungi root colonization increases the production of essential isoprenoids vs. nonessential isoprenoids especially under drought stress conditions or after jasmonic acid application

Previous studies have shown that root colonization by arbuscular mycorrhiza (AM) fungi enhances plant resistance to abiotic and biotic stressors and finally plant growth. However, little is known about the effect of AM on isoprenoid foliar and root content. In this study we tested whether the AM symbiosis affects carbon resource allocation to different classes of isoprenoids such as the volatile nonessential isoprenoids (monoterpenes and sesquiterpenes) and the non-volatile essential isoprenoids (abscisic acid, chlorophylls and carotenoids). By subjecting the plants to stressors such as drought and to exogenous application of JA, we wanted to test their interaction with AM symbiosis in conditions where isoprenoids usually play a role in resistance to stress and in plant defence. Root colonization by AM fungi favoured the leaf production of essential isoprenoids rather than nonessential ones, especially under drought stress conditions or after JA application. The increased carbon demand brought on by AM fungi might thus influence not only the amount of carbon allocated to isoprenoids, but also the carbon partitioning between the different classes of isoprenoids, thus explaining the not previously shown decrease of root volatile isoprenoids in AM plants. We propose that since AM fungi are a nutrient source for the plant, other carbon sinks normally necessary to increase nutrient uptake can be avoided and therefore the plant can devote more resources to synthesize essential isoprenoids for plant growth.     

Biofortification of wheat with iron through soil and foliar application of nitrogen and iron fertilizers

Increasing iron (Fe) concentration in food crops is an important global challenge due to high incidence of Fe deficiency in human populations. Evidence is available showing that nitrogen (N) fertilization increases Fe concentration in wheat grain. This positive impact of N on grain Fe was, however, not studied under varied soil and foliar applications of Fe. Greenhouse experiments were conducted to investigate a role of soil- and foliar-applied Fe fertilizers in improving shoot and grain Fe concentration in durum wheat (Triticum durum) grown under increasing N supply as Ca-nitrate. Additionally, an effect of foliar Fe fertilizers on grain Fe was tested with and without urea in the spray solution. Application of various soil or foliar Fe fertilizers had either a little positive effect or remained ineffective on shoot or grain Fe. By contrast, at a given Fe treatment, raising N supply substantially enhanced shoot and grain concentrations of Fe and Zn. Improving N status of plants from low to sufficient resulted in a 3-fold increase in shoot Fe content (e.g., total Fe accumulated), whereas this increase was only 42% for total shoot dry weight. Inclusion of urea in foliar Fe fertilizers had a positive impact on grain Fe concentration. Nitrogen fertilization represents an important agronomic practice in increasing grain Fe. Therefore, the plant N status deserves special attention in biofortification of food crops with Fe.     

The effect of foliar nutrition on yield of greenhouse tomatoes and quality of the crop

Tomatoes grown in traditional mediums such as peat moss are usually supplied with essential nutrients by preplant fertilization and in the later growth stages by top dressing application to the root zone. According to the data from literature the efficient method of nutrient supply during the intensive stage of growth may be estimated as by foliar spraying. In the greenhouse experiment conducted in 1998–1999 a preplant fertilization by multicomponential fertilizer MIS-4 was applied to peat moss growing medium in full (4 kg per m³) and half (2 kg per m³) of recommended rate. Supplemental fertilization during the growing period was provided to the root zone or by using liquid multicomponential fertilizers Ekolist S and Mikrosol U in 5 sprays conducted at two week intervals. Results of the study proved that advantageous effect of foliar tomato nutrion grown in eat substrate was observed only in treatments with restricted supply of fertilizers to the growing medium. The maximum fruit yield was received from plots provided by the reduced preplant MIS-4 dose to 50 % of recommended rate combined with foliar sprays by Ekolist S. Such system of fertilization enhanced the marketable yield of fruit by 9.8 % and early yield by 11.3 % as compared to that obtained with preplant and top dressing soil application. Foliar nutrion did not change dry matter and vitamin C content and increased total and reducing sugars accumulation in tomato fruits.     

磷素营养对降香黄檀幼苗生长及叶片养分状况的影响

设置0、15、30、60、100、150 mg P·株^-1等6个磷素处理开展降香黄檀幼苗盆栽试验,测定各处理幼苗的生长、生物量、叶片养分含量等指标,采用临界浓度法确定降香黄檀幼苗的适宜施磷量,从而探讨不同磷素水平对降香黄檀幼苗生长和叶片养分状况的影响,揭示其磷素需求规律以及适宜的磷供应范围。结果显示磷肥能促进幼苗生长和生物量的积累,而且随施磷量的增加,各指标呈现先升高后降低的趋势,最高值出现在60 mg P·株^-1处理,其苗高、地径、叶面积、生物量分别为对照的3.07、2.35、49.21和24.25倍。施磷显著降低幼苗叶片氮、钾含量,提高磷、镁含量,其中30、60、100 mg P·株^-13个处理间叶片磷含量差异不显著,约为对照的1.65倍。根据幼苗生物量与叶片磷含量、氮钾含量比、磷钾含量比的抛物线关系,确定叶片最适磷含量范围为1.35~2.32 g·kg^-1,由此推断降香黄檀幼苗最适宜的施磷量为60~100 mg P·株^-1。     

氮硅肥配施对水稻生长、产量及土壤肥力的影响

采用田间试验研究了氮硅肥配施对水稻生长、产量、养分吸收及土壤养分含量的影响。结果表明 ,氮、硅肥单施都能促进水稻生长及对养分的吸收 ,氮肥效果好于硅肥。氮硅肥配施下 ,水稻有效穗数、穗实粒数、千粒重、水稻产量以及水稻地上部生物量 ,植株氮、磷、钾、硅养分含量增幅均高于氮肥和硅肥单施。随施硅量增加 ,氮 /硅比率后期有明显下降趋势。氮硅配施提高了土壤速效氮含量和有效硅含量、降低了土壤速效钾含量 ,而对速效磷、pH、有机质及全氮无明显影响。     

Carbon dioxide‐ and temperature‐mediated changes in plant defensive compounds alter food utilization of herbivores

Although the impact of elevated carbon dioxide and rising temperature on plants and animals has been extensively documented recently, only limited understanding exists regarding their combined effects. The objective of this research was to address the consequences of using combinations of elevated CO₂ and elevated temperature on a plant's defensive chemistry, and subsequent utilization of the plant as insect food. Our results indicated that elevated CO₂ and increased temperature, for the most part, act independently on the production of defensive compounds in broccoli leaves (Brassica oleracea L. var. italica). CO₂ concentrations had significant effects on the foliar water content, total phenolic compounds, polyphenol oxidase and trypsin inhibitor concentrations. The herbivore Spodoptera litura (Fabricius; Lepidoptera: Noctuidae) responded to changes in the plant secondary chemistry, with larvae consuming more plant materials that had been exposed to elevated CO₂. The food utilization efficiencies of second‐instar larvae were more sensitive to CO₂‐treated foliage than those of the third‐ and fourth‐instar larvae. Temperature did exert a significant effect on food utilization (ECD) by the larvae. Our study will provide important information in future predictions on plant–insect interactions as a result of climate change. The study also demonstrated that since various larval stages might respond differently to climate change, this possibility needs to be considered in future forecasting and monitoring.     

Interactions between above- and belowground insect herbivores as mediated by the plant defense system

Plants are frequently attacked by both above- and belowground arthropod herbivores. Nevertheless, studies rarely consider root and shoot herbivory in conjunction. Here we provide evidence that the root-feeding insect Agriotes lineatus reduces the performance of the foliage feeding insect Spodoptera exigua on cotton plants. In a bioassay, S. exigua larvae were allowed to feed on either undamaged plants, or on plants that had previously been exposed to root herbivory, foliar herbivory, or a combination of both. Previous root herbivory reduced the relative growth rates as well as the food consumption of S. exigua by more than 50% in comparison to larvae feeding on the undamaged controls. We found no effects in the opposite direction, as aboveground herbivory by S. exigua did not affect the relative growth rates of root-feeding A. lineatus . Remarkably, neither did the treatment with foliar herbivory affect the food consumption and relative growth rate of S. exigua in the bioassay. However, this treatment did result in a significant change in the distribution of S. exigua feeding. Plants that had been pre-exposed to foliar herbivory suffered significantly less damage on their young terminal leaves. While plant growth and foliar nitrogen levels were not affected by any of the treatments, we did find significant differences between treatments with respect to the level and distribution of plant defensive chemicals (terpenoids). Exposure to root herbivores resulted in an increase in terpenoid levels in both roots as well as in mature and immature foliage. Foliar damage, on the other hand, resulted in high terpenoid levels in young, terminal leaves only. Our results show that root-feeding herbivores may change the level and distribution of plant defenses aboveground. Our data suggest that the reported interactions between below- and aboveground insect herbivores are mediated by induced changes in plant secondary chemistry.     

基于Illumina MiSeq测序平台分析长期不同施肥处理对黑土真菌群落的影响

【目的】不合理施肥所引发的土壤环境问题逐渐成为制约我国农业可持续发展的重要因素之一,土壤真菌作为一类重要的土壤微生物,研究长期施肥对土壤真菌多样性及群落分布格局,探讨其理化因子对真菌群落结构的影响具有一定意义。【方法】本研究以东北黑土玉米田长期定位施肥试验(1984–2017)为基础,通过常规分析和Illumina Mi Seq高通量测序技术,分析长期施肥对黑土玉米田土壤养分含量和真菌群落结构变化的影响。【结果】长期施用氮肥明显降低土壤p H,却增加了玉米产量,秸秆与化肥配施可以增加土壤有机质和全氮的含量。稀释曲线结果表明长期施肥降低了土壤真菌序列的丰度和均匀度,并且在秸秆与化肥配施中序列数最低;在优势菌群中,共检测出5个已知真菌门,分别是子囊菌门(Ascomycota)、担子菌门(Basidiomycota)、接合菌门(Zygomycota)、球囊菌门(Glomeromycota)和壶菌门(Chytridiomycota),子囊菌门占总序列平均值的57.0%,并且在氮磷钾配施高量秸秆有机肥(NPK+S0.5)的土壤中,子囊菌门丰度高达70.35%。在土壤真菌属水平的物种丰度分析中,共检测出109个已知真菌属,Humicola、Fusarium、Verticillium、Mortierella这4个菌属为优势菌属;Chaetomium、Trichocladium、Podospora、Preussia 4个菌属在秸秆与化肥配施处理中丰度较高,并同属一个分支聚类。从多样性指数分析得出,秸秆与化肥配施可以增加物种丰度和群落多样性;从热图分析可知,施用氮肥和不施用氮肥处理间真菌群落组成存在明显差异。RDA分析中,土壤理化性质影响着土壤真菌群落结构,尤其是土壤的p H、全量氮磷钾(T-N、T-P、T-K)、有效磷钾(A-P、A-K)和铵态氮(NH4+-N)浓度是重要环境因素。【结论】因此,施用氮肥虽然增加了产量,但也造成土壤酸化,真菌数量增加,其丰富度和多样性明显降低。而秸秆与化肥配施可以维持土壤健康生态环境和真菌群落多样性。     

Foliar application of melatonin delay leaf senescence in maize by improving the antioxidant defense system and enhancing photosynthetic capacity under semi-arid regions

Melatonin is an important plant growth regulator which plays a key role in plant growth and development. The objective of the current research was to evaluate the effect of foliar application of melatonin (MF) on photosynthetic efficiency, antioxidant defense mechanism, and its relation with leaf senescence in maize crop grown in a semi-arid region. A field experiment was conducted during 2017 and 2018 growth season, where melatonin was applied to the foliage at concentrations of 0 (MF₀), 25 (MF₁), 50 (MF₂), and 75 (MF₃) μM at the ninth leaf stage. Foliar application of melatonin significantly improved chlorophyll content, net photosynthetic rate, soluble sugar content, and soluble protein content during the process of leaf senescence. The application of melatonin also enhanced antioxidant enzyme activities including superoxide dismutase, catalase, and peroxidase, while reduced malondialdehyde and reactive oxygen species accumulation. Melatonin foliar application also increased total leaf area per plant, grains per ear, thousand grain weight and grain yield of maize crop in a semi-arid region. The application of melatonin significantly improved photosynthetic activity, antioxidant defense mechanism, and yield of maize crop in a semi-arid region, where the most effective treatment was MF2.

     

Foliar metabolic heat rate of seedlings and mature trees of Pinus ponderosa exposed to acid rain and ozone

We investigated the effects of acid rain and ozone on respiration rates of 1-year-old and current-year foliage of half-sib seedlings and mature clones of a ponderosa pine genotype by measurement of foliar metabolic heat rates. Two rain regimes (pH 5-1 and 3-0) were applied weekly to foliage only, from January to April 1992. Two ozone regimes (ambient and twice-ambient) were applied from September 1991 to November 1992. Metabolic heat rate was measured in April on 1-year-old foliage, in June on both 1-year-old and current-year foliage, and in November on current-year foliage in 1992. Except for current-year foliage in June, the metabolic heat rate was calculated per unit of both foliar dry mass and N mass. In seedlings, both measures of metabolic heat rate increased in late June for 1-year-old foliage exposed to twice-ambient ozone, and in November for current-year foliage exposed to the combination of twice-ambient ozone and pH 3-0 rain. In mature trees, metabolic heat rate was not affected significantly by ozone, rain acidity, or their interaction. In June, when both 1-year-old and current-year tissues were examined, the metabolic heat rate of expanding, current-year foliage was higher than that of fully expanded, 1-year-old foliage regardless of plant age or treatment combination.     

叶面喷施微肥对川白芷主要有效成分含量的影响

在川白芷生长旺盛期叶面喷施锌、硼、钼,研究微量元素锌、硼、钼配合喷施对川白芷主要有效成分含量的影响以及最适宜的喷施量.结果表明: 叶面喷施锌、硼、钼有利于川白芷欧前胡素和总香豆素含量的提高,对异欧前胡素含量的影响不显著;硼对欧前胡素和总香豆素含量的积累影响最大,锌次之,钼最小;硼和钼互作对欧前胡素含量有拮抗效应,锌和硼互作对总香豆素含量有协同效应;施锌0.15～0.24 kg·hm^-2、硼2.02～2.36 kg·hm^-2、钼0.08～0.13 kg·hm^-2时,川白芷总香豆素含量≥0.7%;施锌0.15～0.20 kg·hm^-2、硼1.37～1.47 kg·hm^-2、钼0.09～0.13 kg·hm^-2时,欧前胡素含量≥0.2%.叶面喷施锌、硼、钼有利于川白芷中香豆素类成分的积累和品质的提高.     

Intra-plant host selection, oviposition preference and larval survival of Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae: Paropsini) between foliage types of a heterophyllous host

Abstract 1 Paropsine chrysomelid beetles defoliate commercial eucalypt plantations in Australia. Adults and larvae feed on the same host, with the larval food source determined by the oviposition choice of females. Most eucalypt species are heterophyllous, with their foliage undergoing distinct morphological and chemical changes between adult and juvenile growth. 2 The intra‐plant foliage feeding and oviposition preference adults and the larval development of Chrysophtharta agricola were examined using adult and juvenile foliage of a heterophyllous plantation species, Eucalyptus nitens. The foliage types differ in chemistry, toughness, waxiness and timing of production. 3 In the field, feeding damage caused by adult beetles was 15% more frequent on adult foliage than on juvenile foliage; however, egg batches were three times more common on juvenile than on adult foliage. 4 Oviposition preference for juvenile foliage over adult foliage was confirmed in choice trials in the laboratory, with adult fecundity and longevity not significantly different between foliage types. 5 Larval survival, development time and subsequent pupal weight were also unaffected by foliage type, suggesting that neither foliage type is nutritionally superior for adults or for larvae. However, adult foliage was significantly thicker than juvenile foliage and this may prove a physical constraint to larval establishment. Biotic and abiotic factors (including interactions with natural enemies, competition, microclimate and mate location) that may affect patterns of host plant utilization are discussed.