Observations on feeding and population structure of five New Zealand terrestrial planarians which prey on lumbricid earthworms

The feeding of five terrestrial planarians found in New Zealand on European lumbricid earthworms was studied. Under laboratory conditions between 60–83% of Artioposthia spp. fed in the first 24 h compared with 21–40% of Australoplana spp. The mean percentage weight gain varied from 31% for Australoplana sanguinea var. alba to 113% for Artioposthia sp. 1. Analysis of the weights of the planarian species showed a mean 11-fold difference between Australoplana sanguinea and Artioposthia triangulata and that these body weights were not related to mean percentage weight gains after feeding. The relationship between the weights of egg capsules and pregnant female planarians was similar for Australoplana sanguinea var. alba (11%), Artioposthia triangulata (12%) and Artioposthia testacea (13%). This study confirms that there are terrestrial planarians in New Zealand which have the potential to prey upon European lumbricid earthworms but which have not been detected in Europe. Greater knowledge of their biology is necessary to control the spread and impact of these organisms around the world.     

Isozyme evidence for the allotriploid origin of Lycoris flavescens (Amaryllidaceae)

 Variation in isozyme patterns from ten populations of the Korean endemic Lycoris species was used to test the hypothesis that L. flavescens originated from natural hybridization between diploid L. chinensis and L. sanguinea var. koreana. Lycoris sanguinea var. koreana shows fixed heterozygosity at four of nine loci assayed, suggesting that this species is an allotetraploid instead of a diploid. Electrophoretic data suggest that Lycoris flavescens is an allotriploid species derived from the hybridization between diploid L. chinensis and tetraploid L. sanguinea var. koreana. The patterns of allelic distribution in populations of L. flavescens suggest multiple origins of the allotriploid. Within the L. flavescens complex, our isozyme data support the recognition of two taxa, L. flavescens and a recently recognized species, L. uydoensis. Received August 28, 2000 Accepted December 27, 2000     

Phylogenetic Relationships and Possible Hybrid Origin of Lycoris Species (Amaryllidaceae) Revealed by ITS Sequences

To examine interspecific relationships and test the hypothesis of hybrid origin within Lycoris species, this study used data from parsimony analyses with nuclear ITS sequences for 19 taxa representing 14 species of Lycoris and two outgroup taxa. The ITS sequences resolved three infrageneric clades. One clade included L. chinensis, L. longituba, L. longituba var. flava, L. anhuiensis, and L. aurea; the second one consisted of L. sprengeri, L. radiata, L. radiata var. radiata, L. radiata var. pumila, L. haywardii, L. rosea, L. sanguinea var. sanguinea, and L. sanguinea var. koreana; and the third included L. caldwellii, L. straminea, L. albiflora, L. flavescens, and two hybrids. The results strongly support the hypothesis that L. straminea originated from hybridization between L. chinensis and L. radiata var. pumila, and the allotriploid L. caldwellii and L. albiflora derived from hybridization between L. chinensis and L. sprengeri. As nucleotide additivity was observed in the artificial hybrids and several presumed hybrids, the likelihood of hybrid origin of Lycoris species is supported.These authors contributed equally to this work.     

A comparison of genetic variation among wild and cultivated Morus Species (Moraceae: Morus) as revealed by ISSR and SSR markers

In this study, inter-simple sequence repeats (ISSR) ans simple sequence repeat (SSR) markers were used to investigate genetic diversity of 27 mulberry accessions including 19 cultivated accessions (six M. multicaulis, three M. alba, two M. atropurpurea, two M. bombycis, one M. australis, two M. rotundiloba, one M. alba var. pendula, one M. alba var. macrophylla, and one M. alba var. venose) and 8 wild accessions (two M. cathayana, two M. laevigata, two M. wittiorum, one M. nigra and one M. mongolica). ISSRs and SSRs were compared in terms of their informativeness and efficiency in a study of genetic diversity and relationships among 27 mulberry genotypes. SSRs presented a higher level of polymorphism and greater information content. All index values of genetic diversity both markers analyzed using Popgene 32 software indicated that within wild species had higher genetic diversity than within cultivated species. Cultivation may caused the lose of genetic diversity of mulberry compared with wild species revealed by ISSR and SSR markers. The mean genetic similarity coefficients among all mulberry genotypes ascribed by ISSR and SSR matrices were 0.7677 and 0.6131, respectively. For all markers a high similarity in dendrogram topologies was obtained although some differences were observed. Cluster analysis of ISSR and SSR using UPGMA method revealed that the wild species are genetically distant from the domesticated species studied here. The correlation coefficients of similarity were statistically significant for both marker systems used. Principal coordinates analysis (PCA) for ISSR and SSR data also supports their UPGMA clustering. These results have an important implication for mulberry germplasm characterization, improvement, molecular systematics and conservation.     

Food consumption and utilisation by larvae of two coccinellid predators, Scymnus levaillanti and Cycloneda sanguinea, on cotton aphid, Aphis gossypii

This study was carried out under laboratory conditions at various temperatures to compare food consumption and efficiency of conversion of food to body mass for larvae of two coccinellid predators, Scymnus levaillanti Mulsant (Coleoptera: Coccinellidae) and Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae), which differ in body size and feeding method. The consumption rate of each larval stage of both species increased with increasing temperature. The consumption rate for total development (from egg hatch to pupation) of S. levaillanti was found to be 22.9 aphids per day at 30°C. It was much higher for C. sanguinea (975.1 aphids per day at 25°C and 1066 aphids per day at 30°C). The larger species, C. sanguinea was more voracious at each temperature than the smaller species, S. levaillanti. The larvae of S. levaillanti, employing pre-oral digestion, were more efficient in converting food to body mass than larvae of C. sanguinea, which used chewing and sucking. The fourth instars of both species were less efficient in converting food to body mass than were their first three instars. It was concluded that body size and feeding method of coccinellid predators play an important role in food consumption and efficiency of conversion of food to body mass.     

Parasitism as a biological control agent of dinoflagellate blooms in the California Current System

Amoebophrya is a marine parasite recently found to infect and kill bloom-forming dinoflagellates in the California Current System (CCS). However, it is unknown whether parasitism by Amoebophrya can control dinoflagellate blooms in major eastern boundary upwelling systems, such as the CCS. We quantified the abundance of a common bloom-forming species Akashiwo sanguinea and prevalence of its parasite (i.e., % infected cells) in surface water samples collected weekly from August 2005 to December 2008 at the Santa Cruz Wharf (SCW), Monterey Bay, CA. Additionally, we measured physical and chemical properties at the SCW and examined regional patterns of wind forcing and sea surface temperature. Relative abundance of the net phytoplankton species was also analyzed to discern whether or not parasitism influences net phytoplankton community composition. Epidemic infection outbreaks (>20% parasite prevalence in the host species) may have contributed to the end or prevented the occurrence of A. sanguinea blooms, whereas low parasite prevalence was associated with short-term (≤2 weeks) A. sanguinea blooms. The complete absence of parasitism in 2007 was associated with an extreme A. sanguinea bloom. Anomalously strong upwelling conditions were detected in 2007, suggesting that A. sanguinea was able to outgrow Amoebophrya and ‘escape’ parasitism. We conclude that parasitism can strongly influence dinoflagellate bloom dynamics in upwelling systems. Moreover, Amoebophrya may indirectly influence net phytoplankton species composition, as species that dominated the net phytoplankton and developed algal blooms never appeared to be infected.     

Prey preferences of the polyclad flatworm Prostheceraeus roseus among Mediterranean species of the ascidian genus Pycnoclavella

In the present study we analyzed prey preferences of the polyclad flatworm Prostheceraeus roseus among three different species of colonial ascidians of the genus Pycnoclavella occurring sympatrically in the Northwestern Mediterranean (Spain). Palatability assays were conducted in laboratory conditions in order to test predator preferences in pairwise tests, and cycles of abundance of the predator and prey were monitored in the field. The results showed a clear preference of the predator for Pycnoclavella communis over Pycnoclavella nana and Pycnoclavella aurilucens. We suggest that chemical variation in defense compounds among species of this secondary metabolite-rich genus can drive the flatworm preferences. The ascidian had seasonal cycles in the area studied, with resting (aestivation) states in the summer months. The flatworm abundance showed no clear seasonal cycle, but it was less abundant in winter. The predator has been seen in the field feeding either on active zooids or on the reserve-laden basal mass of tunic during the aestivation phase of P. communis. Handling editor: I. Nagelkerken     

Genome sequence and genetic transformation of a widely distributed and cultivated poplar

Populus alba is widely distributed and cultivated in Europe and Asia. This species has been used for diverse studies. In this study, we assembled a de novo genome sequence of P. alba var. pyramidalis (= P. bolleana) and confirmed its high transformation efficiency and short transformation time by experiments. Through a process of hybrid genome assembly, a total of 464 M of the genome was assembled. Annotation analyses predicted 37 901 protein‐coding genes. This genome is highly collinear to that of P. trichocarpa, with most genes having orthologs in the two species. We found a marked expansion of gene families related to histone and the hormone auxin but loss of disease resistance genes in P. alba if compared with the closely related P. trichocarpa. The genome sequence presented here represents a valuable resource for further molecular functional analyses of this species as a new tree model, poplar breeding practices and comparative genomic analyses across different poplars.     

庙岛群岛南五岛灌木群落结构及其对环境因子的响应

该研究对山东省庙岛群岛南五岛灌木植被及环境因子进行调查,运用TWINSPAN等级划分法和多元分析技术研究调查区域内灌木的植被分布、群落结构及其与环境因子间的关系。结果显示:(1)调查期间庙岛群岛南五岛共发现灌木27种,隶属于15科23属,荆条、扁担木、酸枣为优势种。(2)灌木群丛主要被划分为6个群丛,即桑群丛、刺槐-柘树群丛、酸枣群丛、扁担木群丛、荆条群丛、紫穗槐群丛。(3)应用典范对应分析(CCA)并采用向前引入法对环境因子进行逐步筛选,Monte Carlo置换检验结果显示,乔木层盖度、土壤pH是影响庙岛群岛南五岛灌木空间分布的关键环境因子。研究认为,CCA二维排序结果与TWINSPAN分类结果较为一致,庙岛群岛南五岛森林灌木群落主要分布于乔木层盖度适中、偏酸性土壤的环境下。     

Intra‐ and interspecific interactions between aphidophagous ladybirds: the role of prey in predator coexistence

Cannibalism (CANN) and intraguild predation (IGP) may provide energy and nutrients to individuals and eliminate potential competitors. These negative competitive interactions could also affect the coexistence of predatory species. The co‐occurrence of aphidophagous ladybird species in crops creates opportunities for CANN and IGP, especially when aphids become scarce. The Lotka–Volterra model predicts the coexistence of two species if intraspecific competition is stronger than interspecific interference interactions. Cycloneda sanguinea L. and Eriopis connexa (Germar) (both Coleoptera: Coccinellidae) coexist in sweet pepper crops in La Plata (Argentina) consuming mainly Myzus persicae (Sulzer) (Hemiptera: Aphididae). The present study used laboratory experiments to estimate levels of CANN and IGP by adults and larvae on eggs, and by adults on larvae, in both the presence and absence of prey (i.e., M. persicae), to explain the effect of prey on coexistence of these two predators. Levels of CANN by C. sanguinea and E. connexa were high in the absence of aphids, and decreased when prey was present. Intraguild predation was bidirectional and asymmetric. Adults and larvae of E. connexa were more voracious IG predators of C. sanguinea than vice versa, the former being the stronger IG predator and interference competitor. Eriopis connexa always won when larvae of the same instar were compared, whereas the larger larva always won when larvae were of different instars, regardless of species. In the presence of prey, CANN by both species decreased, but IGP by E. connexa on C. sanguinea remained high, suggesting that E. connexa could displace C. sanguinea via interspecific interference competition. Other factors potentially affecting the coexistence of C. sanguinea and E. connexa in sweet pepper crops are discussed.     

Characteristics of Encelia species differing in leaf reflectance and transpiration rate under common garden conditions

Summary The performance of coastal and desert species of Encelia (Asteraceae) were evaluated through common garden growth observations. The obectives of the study were to evaluate the roles of leaf features, thought to be of adaptive value (increased leaf reflectance and/or transpirational cooling), on plant growth in the hot, arid, desert garden versus their impact on growth under cooler, relatively more moist coastal garden conditions. E. californica native to the coast of southern California and E. farinosa, and E. frutescens, interior desert species, were grown in common gardens at coastal (Irvine, California) and interior (Phoenix, Arizona) sites under both irrigated and natural conditions. Although all species survived in both gardens during the two and a half year study period, there were large differences in their sizes. In the desert garden, leaf conductance and leaf water potential were both lower than at the coastal site. E. californica shrubs were leafless much of the time under natural conditions in the desert garden and had the smallest size there as well. Under natural conditions, E. farinosa, with its reflective leaf surface, was able to maintain lower leaf temperatures and attained a large size than the other two species in the desert garden. The green-leaved species (E. californica and E. frutescens) were not able to maintain leaves into the drought periods in the desert garden, with the exception of the irrigated E. frutescens which did maintain its leaf area if provided with supplemental watering to maintain transpirational leaf cooling. In the coastal garden, all species survived and there were few clear differences in the physiological characteristics among the three species. E. californica, the coastal native, attained a larger size in the coastal garden when compared with either of the two desert species.     

Zur Kenntnis einiger Arten vonEuglena

Zusammenfassung Beim Studium einer größeren Zahl ökologisch verschiedener Arten vonEuglena in Reinkultur ergab sich folgendes: morphologisch, brauchten die früheren Angaben nur ergänzt zu werden, wobei die reversible Modifizierbarkeit noch besser gegen die erbliche Variabilität abgegrenzt wurde.Die einzige, bisher eingehend physiologisch untersuchte ArtEuglena gracilis ist ein durch weite Anpassungsfähigkeit in der Ernährung ausgezeichneter extremer Fall. Doch machen auch Stämme vonEuglena deses undEuglena viridis guten Gebrauch von organischen Nährstoffen, währendEuglena acus undEuglena sanguinea ganz phototroph sind.Euglena pisciformis ist gleichfalls phototroph, gedeiht aber auch in verschmutztem Wasser, was beiEuglena sanguinea nur in geringem Maße der Fall ist.FürEuglena deses var.Mesnili wurden in der Literatur verbreitete Mißverständnisse und Fehlschlüsse berichtigt.Allen Arten gemeinsam ist der Bedarf an Vitamin B₁₂ und die Bevorzugung von Ammonstickstoff, während die Verwertung von Nitrat nur selten vorkommt.Wachstum im Dunkeln ist nur bei wenigen Arten erzielt worden. Sie ist mit dem Unterbleiben der Chlorophyllbildung verbunden.Die Ergebnisse entsprechen im großen und ganzen den Bedingungen an den Standorten der Arten.

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Summary By studying a number of ecologically differing species ofEuglena in axenic cultures the following results were obtained:With respect to morphology my earlier statements only needed supplementing. Reversible modificability gained a clearer separation from hereditary variability.The only species hitherto thoroughly investigated as to its physiology wasEuglena gracilis. It proved to be an extreme case of nutritional adaptability being able to live photoautotrophically as well as to utilize various organic nutrients and even to grow almost as luxuriantly in the dark as in the light.Strains ofEuglena deses andEuglena viridis may also make good use of organic nutrients, though not producing without photosynthesis populations as dense as those ofEuglena gracilis. Euglena acus andEuglena sanguinea are quite predominantly phototrophic, and so isEuglena pisciformis which, however, penetrates into polluted water, a faculty not so well developed inEuglena sanguinea. Euglena deses var.Mesnili had been the object of widespread misunderstanding and wrong conclusions which were corrected in detail.All species have in common a requirement of vitamin B₁₂ and the preference of Ammon-N, while utilization of Nitrate is a rare instance.Growth in the dark has been achieved only in a few species. It is always combined with the lack of chlorophyll formation.On the whole the results are conform to the conditions at the respective habitats.

     

Morphogenic response of the alginate-encapsulated axillary buds from in vitro shoot cultures of six mulberries

Axillary buds obtained from in vitro shoot cultures of six mulberries (Morus alba L., M. australis Poir., M. bombycis Koidz., M. cathyana Hemsl., M. latifolia Poir., and M. nigra L.) were encapsulated in calcium alginate hydrogel containing Murashige and Skoog (1962) nutrients (MS) and 4.4 μM benzyladenine (BA). Morphogenic response of encapsulated buds to various planting media such as MS medium + 4.4 μM BA, MS basal medium, soilrite mix + half-strength MS medium, garden soil + half-strength MS medium, soilrite mix + tap water and garden soil + tap water was evaluated. Encapsulated buds of M. alba, M. bombycis, M. latifolia and M. nigra exhibited shoot development in each of the six media tested whereas that of M. australis and M. cathyana responded only to the first four media. Analysis of variance revealed that the planting medium exhibited the greatest influence on shoot development. Of the six planting media evaluated, shoot development was highest in MS medium containing 4.4 μM BA and lowest in garden soil moistened with water. Of the six Morus species studied, one-step regeneration, i.e. both shoot and root formation, was recorded in M. alba, M. bombycis and M. latifolia. Rooted shoots were retrieved from encapsulated buds of these species on all planting media tested except the one that contained BA. Root development was significantly affected by the planting medium and the plant species with planting medium contributing the maximum amount (82%) of the total variation observed. Of the five planting media tested, the percentage of root development was highest in MS basal medium. Of the six Morus species studied, the best shoot and root development was observed in M. alba. Encapsulated buds of M. bombycis, M. latifolia and M. nigra stored for 90 days and those of M. alba, M. australis and M. cathyana for 60 days at 4 °C still regenerated shoots. Plants regenerated from the encapsulated buds were hardened off and transferred to soil. This revised version was published online in June 2006 with corrections to the Cover Date.     

Antioxidant and Pigment Composition during Autumnal Leaf Senescence in Woody Deciduous Species Differing in their Ecological Traits

Abstract: Photoprotection mechanisms have been studied during autumnal senescence in sun and shade leaves of woody plants with different ecological characteristics and senescence patterns. Three of them belonging to the same family, Betulaceae: the shade‐intolerant and early successional species (Betula alba L.), the shade‐tolerant and late successional species (Corylus avellana L.), and an N‐fixing tree with low N resorption efficiency (Alnus glutinosa L.). The other two species: a shade‐intolerant (Populus tremula L.) and a shade‐tolerant (Cornus sanguinea L.), were chosen because of their ability to accumulate anthocyanins during autumnal leaf senescence. The study of plants with different ecological strategies allowed us to establish general trends in photoprotection mechanisms during autumnal senescence, when nutrient remobilisation occurs, but also during whole leaf ontogeny. We have not found a clear relationship between shade tolerance and the level of photoprotection; the main difference between both groups of species being the presence of α‐carotene in shade leaves of shade‐tolerant species. Preceding autumn, nitrogen resorption started in mid‐summer and occurred in parallel with a slight and continuous ascorbate, chlorophyll and carotenoid degradation. However, the ascorbate pool remained highly reduced and lipid oxidation did not increase at this time. Contrasting with ascorbate, α‐tocopherol accumulated progressively in all species. Only during the last stages of senescence was chlorophyll preferentially degraded with respect to carotenoids, leading to the yellowing of leaves, except in A. glutinosa in which a large retention of chlorophyll and N took place. Senescing leaves were characterised, except in C. sanguinea, by a relative increase in the proportion of de‐epoxidised xanthophylls: zeaxanthin, antheraxanthin and lutein. The light‐induced accumulation of anthocyanins in C. sanguinea could play an additional protective role, compensating for the low retention of de‐epoxidised xanthophylls. These different strategies among deciduous species are consistent with a role for photoprotective compounds in enhancing nitrogen remobilization and storage for the next growing season.     

Evaluation of some coccinellid species for the biological control of aphids in protected cropping

Four species of Coccinellidae, Adalia bipunctata (L.), Coccinella septem-punctata L., Coelomegilla maculata de G. and Cycloneda sanguinea L., were compared as predators of aphids on cucumbers and chrysanthemums. In laboratory feeding tests C. maculata and C. sanguinea proved the most voracious but the former could not remain on cucumber foliage long enough to be effective. The fecundity of C. sanguinea was the highest of those studied and a satisfactory laboratory rearing technique has been developed for this species.     

Differences between understorey and canopy in herbivore community composition and leaf quality for two oak species in Missouri

1. From July 1994 to September 1995, at six censuses, the herbivore community associated with understorey (< 2.5 m height) and canopy (15–20 m) leaves of Quercus alba and Q. velutina was sampled in south-eastern Missouri, U.S.A. 2. Across all censuses, herbivore densities were not significantly different between canopy and understorey for Q. alba and Q. velutina, except in August 1994 when herbivore densities were 60% higher in the canopy on Q. alba. Little significant spatial variation in herbivore densities or community composition was found during the study years. 3. The herbivore community was diverse, consisting of 138 species of leaf-chewing insects. Species richness was significantly greater (by 5–20%) in the understorey than in the canopy for both tree species, and the relative abundance of the main families, different feeding guilds, and most common species differed significantly between understorey and canopy. 4. To determine the extent to which leaf quality explained the observed patterns, percentage nitrogen and protein binding capacity were measured in canopy and understorey leaves of Q. alba and Q. velutina. Per cent nitrogen was higher in canopy leaves for Q. velutina while protein binding capacity was higher in canopy leaves for Q. alba. 5. These results suggest that the herbivore community associated with these two species of Quercus comprises species that appear to respond individually to environmental and biological conditions encountered in the understorey and the canopy.     

Relationship between climate and growth of two North African varieties of Pinus pinaster Arn.

Planting tree species that are well adapted to local ecological conditions guarantees the success and sustainability of forest restoration. The aim of this study was to investigate the acclimation of two varieties of Pinus pinaster (var. renoui from Tunisia and var. maghrebiana from Morocco), to the ecological conditions of the Kroumirie Mountains in northwest of Tunisia. Tree growth performance (diameter at 1.30 m [DBH], ring widths and total height) and climate–growth responses over the period 1970–2013 were evaluated for two varieties. The trees used in this study were from pine variety and provenance trials growing in common garden in Souiniet (21 trees per variety). Significant difference in height growth rate, DBH and ring widths was found between the two varieties. The Maghrebiana variety had the highest survival and mean radial growth rates. The mean sensitivity to climate was the same in two varieties. A significant negative correlation between May precipitation and radial growth was found for var. maghrebiana. Both varieties showed a significant negative correlation between May and June temperatures and radial growth. January–February temperatures had a positive influence on ring width. The Maghrebiana variety appears well acclimatised so it is expected to ensure more successful restoration of Kroumirie Mountains.     

Recognition of Individuals from Mixed Colony by Formica sanguinea and Formica polyctena Ants

It was examined whether Formica polyctena and F. sanguinea ants from a mixed colony elicit higher levels of aggression of conspecific ants in comparison to ants from homospecific colonies. Individuals were confronted in an experimental arena and their behavior was recorded. It was found that F. polyctena workers behaved more aggressively toward ants from a mixed colony. This pattern, however, was not confirmed in F. sanguinea. Moreover, both species clearly discriminated between conspecific and allospecific ants from a mixed colony. It seems that as a result of social interactions both species exchanged cuticular hydrocarbons, which caused their recognition labels to adjust to some extent. Results of the present study support the idea that that F. sanguinea is able to form mixed colonies in which species-specific recognition cues are probably still retained.     

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.