Pieris Rapae Research Articles

Studies on insect-pests complex in mustard (Brassica juncea L.)

The present investigation was carried out at Students’ Instructional Farm of Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya during Rabi, 2016. Among various Brassica oilseed crop mustard is an important Rabi oilseed crop, attacked by mustard aphid (Lipaphis erysimi), mustard sawfly (Athalia lugens proxima), painted bug (Bagrada hilaris) and cabbage butterfly (Pieris brassicae) insect-pests at different part of plant at different growth stages. The result of present studies revealed that the populations of mustard sawfly appeared at an early stage of crop growth 45th SW of 2016 which continued up to 1st SW of 2017 with varying population ranging from 0.33 grubs/plant to 3.33 grubs/plant. The maximum population of mustard sawfly was recorded as 3.33 grubs/plant in 48th SW of 2016. The 1st occurrence of mustard aphid was recorded during 49th SW of 2016 which continued up to 10th SW of 2017 with varying population ranging from 0.41 to 212.67 aphids/10cm central twig/plant. The peak period of occurrence of mustard aphid was observed in 7th SW of 2017, the maximum population of this insect was recorded as 212.67 aphids/10 cm central twig/plant. The population of painted bug initiated during 2nd SW of 2017 and remained up to 9th SW of 2017.The bug population ranged from 0.33 to 2.67 bugs/plant. The maximum population of bug was recorded as 2.67 bugs/plant in 5th SW of 2017. The other insect-pests (grass hopper, green bug cabbage butterfly, etc.) made its first appearance during 46th SW of 2016 and continued up to 11th SW of 2017 with population varying from 0.33 to 4.00 insects/plant.

Isolation and evaluation of Heterorhabditis bacteriophora strain-s26 as biocontrol agents against Pieris brassicae L. under laboratory conditions

Entomopathogenic nematodes (EPNs) as bio-control have been reported as conventional and intensified method in insect pest management. In the present investigation, a survey was carried out in district Sirmaur to detect the presence of EPNs. In total, 110 soil samples were collected from the rhizospheric soil of fruit plantations and among them 35 samples possess EPNs. Based on morphological analysis, all the isolated EPNs were identified as Heterorhabditis bacteriophora. The insecticidal potential of local isolate of EPN H. bacteriophora strain EUPT-S26 was evaluated against two different larval instars (3rd and 4th instars) of Pieris brassicae (cabbage butterfly) under the laboratory conditions. Different concentrations of nematode inoculums @ 30 infective juveniles (IJs), 60 IJs, 90 IJs, 120 IJs and 150 IJs/ml along with control were applied against both the instars. The rate of pathogenicity was recorded upto 96 h. It was observed that both the instars of P. brassicae were highly susceptible for H. bacteriophora strain EUPT-S26 infection. The inoculum level of 150 IJs was causing highest mortality to both 3rd and 4th larval instars at 96 h of exposure. The data recorded from the present study shows lethal concentration LC50=29.13 IJs (95% FL=21.92–38.71) in 3rd instars and LC50=21.62 IJs (95% FL=16.06–29.10) against 4th instar larvae after 96 h of nematodes exposure. It was concluded from the present investigation, that the local isolates of H. bacteriophora strain EUPT-S26 showed significant mortality among both the larval instars that keeps on enhanced with the increase in nematode inoculum concentration and exposure time. Further studies are required to explore their insecticidal potential against other insect pests in the field condition also.

LABORATORY EVALUATION OF THE EFFECTIVENESS OF THE BIOLOGICAL DRUG ENTOLEK K PLANTECO® ON DIFFERENT SPECIES OF PEST INSECTS OF FODDER CROPS

The article presents the data on the results of laboratory tests of effectiveness of the biological drug Entolek K Planteco® on different species of insect pests of fodder crops. The authors used the following pest species as test-objects - imago of Eurydema ornata(Linnaeus, 1758) (Heteroptera, Pentatomidae), larvae of Tettigonia viridissima(Linnaeus, 1758) (Orthoptera, Tettigoniidae), larvae and adults of Anacanthotermes ahngerianus Jacobson, 1904 (Blattodea, Hodotermitidae), adults of Oxythyrea cinctella (Schaum, 1841) (Coleoptera, Scarabaeidae), caterpillars of Pieris rapae (Linnaeus, 1758) (Lepidoptera, Pieridae). Of the pest arthropods tested, the most resistant to the effects of Entolek K Planteco® were the adults of O. cinctella - the death of insects reached 100% in 15 minutes after treatment. The same resistance was shown by E. ornata. The larvae of T. viridissima showed average resistance - 7 minutes. A. ahngerianus and P. rapae were the most susceptible to the preparation - 99- 100% of insects died 5 minutes after treatment. This difference is largely due to the thickness of the chitinous cover of the insects used as test objects. Based on this, we can say that the Entolek K Planteco® can be used with the greatest effectiveness against insect pests with thin covers or in the younger age of larval stage when they are the least resistant. Also, it may be better used against agricultural pests with thick chitinous covers (beetles, adult bugs, etc.) by increasing the concentration. Based on the results of the studies, Planteco® Entolek K can be used against various pests, which are quite numerous on the crops of fodder crops. Analysis of the obtained results showed that after 7-15 minutes (depending on the pest species), the drug efficiency reaches 99-100%. This efficiency is good enough for a biological preparation and will allow to obtain organic products of fodder crops, and then livestock, containing no toxic residues.

Compatibility of entomopathogenic nematodes with insecticides against the cabbage white butterfly, Pieris rapae L. (Lepidoptera: Pieridae)

BackgroundCompatibility of entomopathogenic nematodes (EPNs) with insecticides is a crucial mainstay of integrated pest management (IPM) programs. This study was designed to evaluate the joint action of EPN species and insecticides when employed to deter 3rd and 4th larval instars of cabbage white butterfly, Pieris rapae L. (Lepidoptera: Pieridae) under laboratory conditions. EPNs [Steinernema carpocapsae (All strain), S. feltiae (Filipjev), Heterorhabditis bacteriophora (HP88), and H. bacteriophora (Ar-4)], at concentrations of 50, 100, and 125 IJs/larva, were tested with 3 insecticides (lambda-cyhalothrin, emamectin benzoate, and indoxacarb) at LC25 and LC50 values. Additionally, expression profiles of 2 detoxification genes (CYP6AE120 and PrGSTs1) when the 4th instar larvae were treated by H. bacteriophora (HP88) and lambda-cyhalothrin were examined.ResultsData indicated that statistically significant mortality of 2 larval instars of P. rapae was observed in vitro among EPN species and pesticide concentrations. At concentration of 50 IJs/larva, LT50 values were 2.385 and 3.92 days for S. carpocapsae (All strain) and H. bacteriophora(Ar-4), respectively, on 3rd instar larvae; also, these values were 3.506 and 3.107 days for S. feltiae and H. bacteriophora (Ar-4), respectively, on 4th instar larvae Lambda-cyhalothrin was the most toxic insecticide, followed by emamectin benzoate and indoxacarb at LC25 and LC50, respectively. An additive effect was observed between EPN species with LC25 and LC50 of the tested insecticides, except for lambda-cyhalothrin at LC50 with H. bacteriophora (Ar-4), and indoxacarb, with all EPNs showing antagonistic effects on mortality of 3rd instar larvae after 3 days post-treatment. The interaction between the tested pesticides at LC25 and LC50 and EPN species, showed an additive effect, excluding lambda-cyhalothrin at LC25 with S. carpocapsae (All strain) and LC25 of indoxacarb with H. bacteriophora (Ar-4), which showed potentiation effects. The interaction of S. feltiae (Filipjev) with tested insecticides at LC50 exhibited an antagonistic effect on the mortality of 4th instar P. rapae larvae after 3 days post-treatment. The expression of both CYP6AE120 and PrGSTs1 was significantly up-regulated with lambda-cyhalothrin, followed by H. bacteriophora (HP88) compared to control.ConclusionsThe findings suggested that combining EPNs and the pesticide concentrations can be a practical strategy for managing P. rapae and could pave the way to using new control technologies in protecting organic farm vegetables from lepidopteran pests.

Effectiveness of biological protection of cabbage against pests in the conditions of the Primorsky Territory

The results of the use of entomophages and biological products to regulate the number of cabbage pests (cabbage moth Mamestra brassicae L., cabbage butterfly Pieris brassicae L., turnip butterfly Pieris rapae L., diamondback moth Plutella xylostella L.) are presented. The study was carried out in the Primorsky Territory in 2018-2020. The efficiency of Trichogramma ussuricum Sorokina applications was assessed on cabbage varieties. The effectiveness of the entomophage against the cabbage moth varied from 33.3 to 66.6%, against the turnip butterfly - from 32.6 to 70.2%. In field experiments the effectiveness of biological products Fitoverm EC (0.09 l/ha), Akarin EC (1.6 l/ha), Proclaim WG (0.3 kg/ha), Bitoxibacillin (10 l/ha), Bitoxibacillin P (2 kg/ha), Lepidocid SC (2 l/ha), Lepidocid P (2 kg/ha) against diamondback moth are studied. Cabbage plants were sprayed with the preparations once. Pest counts were carried out before treatment and after treatment on the 5th, 10th and 15th day in accordance with the approved methods. Bioinsecticide Proclaim showed a high efficiency of 93.0-100% on the 5-10th day. The effectiveness of preparations based on aversectin C and avertin N was 65.0-88.6%. Using the biological product Bitoxibacillin and Lepidocid a decrease the number of diamondback moth relative to the control by 61.2-97.5 и 65.0-78.0% was registered.

Local thermal environment and warming influence supercooling and drive widespread shifts in the metabolome of diapausing Pieris rapae butterflies.

Global climate change has the potential to negatively impact biological systems as organisms are exposed to novel temperature regimes. Increases in annual mean temperature have been accompanied by disproportionate rates of change in temperature across seasons, and winter is the season warming most rapidly. Yet, we know relatively little about how warming will alter the physiology of overwintering organisms. Here, we simulated future warming conditions by comparing diapausing Pieris rapae butterfly pupae collected from disparate thermal environments and by exposing P. rapae pupae to acute and chronic increases in temperature. First, we compared internal freezing temperatures (supercooling points) of diapausing pupae that were developed in common-garden conditions but whose parents were collected from northern Vermont, USA, or North Carolina, USA. Matching the warmer winter climate of North Carolina, North Carolina pupae had significantly higher supercooling points than Vermont pupae. Next, we measured the effects of acute and chronic warming exposure in Vermont pupae and found that warming induced higher supercooling points. We further characterized the effects of chronic warming by profiling the metabolomes of Vermont pupae via untargeted LC-MS metabolomics. Warming caused significant changes in abundance of hundreds of metabolites across the metabolome. Notably, there were warming-induced shifts in key biochemical pathways, such as pyruvate metabolism, fructose and mannose metabolism, and β-alanine metabolism, suggesting shifts in energy metabolism and cryoprotection. These results suggest that warming affects various aspects of overwintering physiology in P. rapae and may be detrimental depending on the frequency and variation of winter warming events. Further research is needed to ascertain the extent to which the effects of warming are felt among a broader set of populations of P. rapae, and among other species, in order to better predict how insects may respond to changes in winter thermal environments.

계층분석방법(AHP)과 전문가 설문조사를 활용한 농업생태계 기후변화 지표생물 30종 선정

It is more efficient to select and monitor a few climate-sensitive organisms to assess the impacts of climate change on agroecosystems. In this study, indicator species of climate change in agroecosystem in South Korea were selected through analytical hierarchy process and an expert questionnaire survey. Climate sensitivity, agroecosystem symbolism, survey easiness, identification easiness, and public interest were selected as criteria for indicator species, with weights of 0.38 (±0.15), 0.23 (±0.13), 0.18 (±0.11), 0.14 (±0.09), and 0.07 (±0.06), respectively. According to these criteria, 30 indicator species were finally selected from six taxonomic groups of plants, aquatic invertebrates, bees, terrestrial beetles, butterflies, and spiders as follows. Seven plant species were selected: Taraxacum officinale, Capsella bursa-pastoris, Veronica persica, Hypochaeris radicata, Lamium amplexicaule, Trigonotis peduncularis, and Conyza sumatrensis. Seven aquatic invertebrate species were selected: Pomacea canaliculata, Cybister chinensis, Hydrochara affinis, Sternolophus rufipes, Hydaticus grammicus, Appasus japonicus, and Rhantus suturalis. Five butterfly species were selected: Eurema mandarina, Chilo suppressalis, Pieris rapae, Papilio xuthus, and Colias erate. Three spider species were selected: Argiope bruennichi, Larinioides cornutus, and Neoscona adianta. Four bee species were selected: Vespa velutha nigrithorax, V. simillima simillima, V. mandarinia, and V. simillima xanthoptera. Four species were selected for terrestrial beetles: Pheropsophus javanus, P. jessoensis, Platydracus brevicornis, and Chlaenius micans. The selected species are expected to be used as indicators for assessing the impacts of climate change in agroecosystems in the future.

The relationship of mean temperature and 9 collected butterfly species\u2019 wingspan as the response of global warming

BackgroundOrganism body size is a basic characteristic in ecology; it is related to temperature according to temperature-size rule. Butterflies are affected in various aspects by climate change because they are sensitive to temperature. Therefore, this study was conducted to understand the effect of an increase in temperature due to global warming on the wing of butterflies.ResultsA total of 671 butterflies belonging to 9 species were collected from 1990 to 2016 in Seoul (336 specimens) and Mokpo (335 specimens). Consequently, as the mean temperature increased, the wing length of the species increased. However, there are exceptions that the Parnassius stubbendorfii, Pieridae canidia, and Pieris rapae wing length of Seoul increased, but the butterfly wing length of Mokpo decreased.ConclusionsThe positive correlations between the butterfly wing length and mean temperature showed that the change of mean temperature for about 26 years affects the wing length of butterfly species. The exception is deemed to have been influenced by the limited research environment, and further studies are needed. We would expect that it can be provided as basic data for studying effect of climate change.

In Search of an Honest Butterfly: Sexually Selected Wing Coloration and Reproductive Traits From Wild Populations of the Cabbage White Butterfly

Abstract Sexual selection is central to many theories on mate selection and individual behavior. Relatively little is known, however, about the impacts that human-induced rapid environmental change are having on secondary sexually selected characteristics. Honest signals function as an indicator of mate quality when there are differences in nutrient acquisition and are thus potentially sensitive to anthropogenically altered nutrient inputs. We used the cabbage white butterfly, Pieris rapae (L.) (Lepidoptera: Pieridae), to investigate differences in color and testes size in a system that is often exposed to agricultural landscapes with nitrogen addition. We collected individuals from four sites in California and Nevada to investigate variation in key traits and the possibility that any relationship between wing color and a reproductive trait (testes size) could vary among locations in the focal butterfly. Coloration variables and testes size were positively albeit weakly associated across sites, consistent with the hypothesis that females could use nitrogen-based coloration in the cabbage white as an indicator for a male mating trait that has the potential to confer elevated mating success in progeny. However, variation in testes size and in the relationship between testes size and wing color suggest complexities that need exploration, including the possibility that the signal is not of equal value in all populations. Thus these results advance our understanding of complex relationships among environmental change and sexual selection in the wild.

The genome sequence of the small white, Pieris rapae (Linnaeus, 1758)

We present a genome assembly from an individual female Pieris rapae (the small white; Arthropoda; Insecta; Lepidoptera; Pieridae). The genome sequence is 256 megabases in span. The majority of the assembly is scaffolded into 26 chromosomal pseudomolecules, with the W and Z sex chromosome assembled. Gene annotation of this assembly on Ensembl has identified 12,390 protein coding genes.

A Laser Irradiation Method for Controlling Pieris rapae Larvae

At present, chemical pesticides remain the main approach for controlling Pieris rapae (L.) (Lepidoptera: Pieridae). This research proposes a novel laser irradiation method for managing P. rapae larvae as an alternative to chemical control. The effectiveness of controlling larvae and the influencing factors of lasers were studied to estimate optimal parameter combinations. Tests using the antifeedant effect and mortality of the larvae as dependent variables showed that the laser power, irradiation area, laser opening time and irradiation position were positively correlated with the P. rapae controlling effect. The optimal parameters for each factor were the following: laser power, 7.5 W; irradiation area, 6.189 mm2; laser opening time, 1.177 s; and irradiation position, middle of the abdomen. Based on these observations, a validation experiment was performed using the optimal combination of parameters, and the results showed that the antifeedant percentage of P. rapae larvae within 24 h posttreatment was 98.49%, whereas the mortality rate was 100%. The optimal parameter combination identified in the study was suitable for P. rapae larvae from the first- to fifth-instar stages, and a more effective controlling effect was observed with the younger larvae. These results can provide a theoretical basis for future pest control using laser pest-killing robots.

Can Symbiotic Bacteria (Xenorhabdus and Photorhabdus) Be More Efficient than Their Entomopathogenic Nematodes against Pieris rapae and Pentodon algerinus Larvae?

Simple SummaryFood security is the people’s main concern, and agricultural crops play a significant role in ensuring it. Agricultural pests, on the other hand, are regarded one of the most serious threats to cause a significant problem for food security. Entomopathogenic nematodes of the genera Herterorhabditids and Sterinernematids fulfil the fundamental requirements of perfect bio-control agents; however, their efficacy mostly dependent on their symbiotic bacteria. As a result, this study aimed to investigate the ability of the isolated symbiotic bacteria (Photorhabdus and Xenorhabdus) to control Pieris rapae and Pentodon algerinus larvae in comparison with their own nematodes, Heterorhabditis bacteriophora and Steinernema riobravis, respectively. The results showed that both nematode species and their symbiotic bacteria were able to suppress both insect species. However, both bacterial genera were more efficient than the investigated nematode species against P. rapae, although nematodes were superior against P. algerinus. Gas chromatography–mass spectrophotometry of Xenorhabdus sp. and Photorhabdus sp. identified the key components with the insecticidal properties. The two bacteria genera were proven to be safe and had no significant effect on normal WI-38 human cells. In conclusion, the symbiotic bacteria can be employed safely and effectively against the tested insects independently on their own entomopathogenic nematodes.Pieris rapae and Pentodon algerinus are considered a global threat to agricultural crops and food security; hence, their control is a critical issue. Heterorhabditid and Steinernematid nematodes, along with their symbiotic bacteria, can achieve the optimal biocontrol agent criterion. Therefore, this study aimed to evaluate the efficacy of Heterorhabditis bacteriophora, Steinernema riobravis, and their symbiotic bacteria (Xenorhabdus and Photorhabdus) against P. rapae and P. algerinus larvae. The virulence of entomopathogenic nematodes (EPNs) was determined at different infective juvenile concentrations and exposure times, while the symbiotic bacteria were applied at the concentration of 3 × 107 colony-forming units (CFU)/mL at different exposure times. Gas chromatography–mass spectrophotometry (GC-MS) analysis and the cytotoxic effect of Photorhabdus sp. and Xenorhabdus sp. were determined. The results indicated that H. bacteriophora, S. riobravis, and their symbiotic bacteria significantly (p ≤ 0.001) induced mortality in both insect species. However, H. bacteriophora and its symbiont, Photorhabdus sp., were more virulent. Moreover, the data clarified that both symbiotic bacteria outperformed EPNs against P. rapae but the opposite was true for P. algerinus. GC-MS analysis revealed the main active compounds that have insecticidal activity. However, the results revealed that there was no significant cytotoxic effect. In conclusion, H. bacteriophora, S. riobravis, and their symbiotic bacteria can be an optimal option for bio-controlling both insect species. Furthermore, both symbiotic bacteria can be utilized independently on EPNs for the management of both pests, and, hence, they can be safely incorporated into biocontrol programs and tested against other insect pests.

Comparative efficacy of synthetic pesticides with botanical extracts under field condition on cabbage white butterfly (Pieris brassicae Linnaeus) (Lepidoptera: Pieridae)

Cabbage white butterfly, Pieris brassicae (L., 1758) (Lepidoptera: Pieridae), is one of the important insect pests of cabbage crop which causes remarkable quantitative or qualitative crop losses. The effect of different new chemical insecticides and one botanical oil, neem seed oil (Azadirachta indica A. Juss.) on the population density of P. brassicae was studied at Hazara Agricultural research station, Abbottabad(Pakistan). The study showed that neem oil had a significant effect on population of P. brassic in comparison to control treatment.So, neem oil alone or in combination with insecticides can be used for control of P. brassicae in vegetable crops for a safer food supply.

Comparative efficacy of synthetic pesticides with botanical extracts under field condition on cabbage white butterfly (Pieris brassicae Linnaeus) (Lepidoptera: Pieridae)

Cabbage white butterfly, Pieris brassicae (L., 1758) (Lepidoptera: Pieridae), is one of the important insect pests of cabbage crop which causes remarkable quantitative or qualitative crop losses. The effect of different new chemical insecticides and one botanical oil, neem seed oil (Azadirachta indica A. Juss.) on the population density of P. brassicae was studied at Hazara Agricultural research station, Abbottabad(Pakistan). The study showed that neem oil had a significant effect on population of P. brassic in comparison to control treatment.So, neem oil alone or in combination with insecticides can be used for control of P. brassicae in vegetable crops for a safer food supply.

Seasonal Abundance of the White Butterfly Pieris rapae L. in the old and reclaimed areas with reference to its relative susceptibility and damage to certain cabbage cultivars

The main goal of this study was to determine the seasonal abundance of the white butterfly Pieris rapae L. (Lepidoptera: Pieridae) on several local and imported cabbage cultivars in old and reclaimed lands. The impact of certain cabbage metabolites on P. rapae populations was examined, as well as the relative susceptibility of different cabbage cultivars. Damage caused by P. rapae Varies. During the first two months following transplantation, P. rapae can cause economic damage to cabbage plants in both areas. One month later, its population had multiplied several times in the old land. Three of the six tested cabbage cultivars were appeared as susceptible (S) cultivars and harbored high numbers of the pest with an average of 0.63, 0.60 and 0.53 Kenz, Crossina and Ganzory cultivars, respectively. However, the imported white cabbage hybrids, 728, 730 and 747 showed sort of resistance and appeared as low resistant (LR) hybrids and harbored 0.40, 0.41 and 0.45 individuals/plant, respectively. Chlorophyll only showed highly significant negative correlation with P. rapae populations. However, the remaining metabolites showed non-significant positive correlation. In a comparison between P. rapae populations in Assiut (the old area) and El-Fath province (the reclaimed area), it can be note that the pest populations, the damaged (infested and unmarketable) plants were multiplied several times in the later. It can be noted that the general mean of the pest numbers recorded in the reclaimed area (2.14 individuals/plant) was found to equal 4.28 folds more than that recorded in the old area (0.50 individuals/plant).

The Use of Synthetic Herbivory-Induced Plant Volatiles That Attract Specialist Parasitoid Wasps, Cotesia vestalis, for Controlling the Incidence of Diamondback Moth Larvae in Open Agricultural Fields

We evaluated the effectiveness of using a blend of volatiles that attract Cotesia vestalis, a specialist parasitoid wasp of diamondback moth (DBM) larvae, to control DBM larvae on cabbage plants under open field conditions. We set three dispensers of the synthetic C. vestalis attractant together with one sugary-food feeder in a cabbage plot (10 m × 1 m; the treated plot) on one side of a pesticide-free open agricultural field (approximately 20 m × 20 m) from June to September in 2010 and July to August in 2011. On the other side of the field, we created a control cabbage plot of the same size in which neither dispensers nor a feeder was set. The incidences of DBM larvae and C. vestalis cocoons in the control and treated plots were compared. In 2010, the incidence of DBM larvae in the treated plot was significantly lower than that in the control plot. Poisson regression analyses in 2010 showed that the rate of increase in the number of C. vestalis cocoons along with an increase in the number of DBM larvae in the treated plot was significantly higher than that in the control plot. In 2011, the incidence in both the treated and control plots remained low (five larvae per plant or less) with no significant difference between the plots. Poisson regression analyses in 2011 showed that the number of C. vestalis cocoons in the treated plot was significantly higher than that in the control plot, irrespective of the number of DBM larvae. This 2-year field study suggested that the dispensers recruited native C. vestalis from the surrounding environment to the treated plot, and the dispensers controlled the number of DBM larvae in 2010 when the density of DBM larvae exceeded the economic injury levels for the cabbage crop. We also compared the incidences of other arthropods in the control and treated plots. The incidences of Pieris rapae larvae and Plusiinae spp. were not affected by the treatments. The number of aphids in the treated and control plots was inconsistent between the 2 years. Based on these 2-year results, the possible use of C. vestalis attractants in open agricultural fields is discussed.

Smart strategy of butterfly wing scales to control the light diffusion and absorption

The sparkling colors on the wing scales of butterflies are one of the most fascinating light–matter interactions in nature and have been an intense area of research in recent times. Controlling the light diffusion and absorption due to multiple scattering induced by the inherent disorder in the wing scales is required for applications in imaging, light trapping, and localization using such bio-inspired photonic structures. Here, we study the selective anisotropic light diffusion and absorption in the nanoarchitectures of Pieris rapae and Graphium sarpedon butterfly wing scales in the visible range. We have measured broadband spatially independent low values of specular reflectivity and ballistic transmission from the ventral and the dorsal sides of the wing scales, which are supported with finite-difference time-domain simulations. The specular reflectivity value as small as 3% indicates strong diffuse scattering within the scales, probed using total transmission and reflection measurements. We have found finite wavelength-dependent absorption < 100 % in these wing scales. Further, we have obtained negative scattering anisotropy ( g ) values from the dorsal side, whereas it is positive from the ventral side for both butterflies. The negative g value originating due to the inherent structural correlation is differentiated from that arising due to pigment absorption. The results are useful for generating the optimized light scattering in bio-inspired photonic devices.

An Independent Evolutionary Origin for Insect Deterrent Cucurbitacins inIberis amara

Pieris rapae and Phyllotreta nemorum are Brassicaceae specialists, but do not feed on Iberis amara spp. that contain cucurbitacins. The cucurbitacins are highly oxygenated triterpenoid, occurring widespread in cucurbitaceous species and in a few other plant families. Using de novo assembled transcriptomics from I. amara, gene co-expression analysis and comparative genomics, we unraveled the evolutionary origin of the insect deterrent cucurbitacins in I. amara. Phylogenetic analysis of five oxidosqualene cyclases and heterologous expression allowed us to identify the first committed enzyme in cucurbitacin biosynthesis in I. amara, cucurbitadienol synthase (IaCPQ). In addition, two species-specific cytochrome P450s (CYP708A16 and CYP708A15) were identified that catalyze the unique C16 and C22 hydroxylation of the cucurbitadienol backbone, enzymatic steps that have not been reported before. Furthermore, the draft genome assembly of I. amara showed that the IaCPQ was localized to the same scaffold together with CYP708A15 but spanning over 100 kb, this contrasts with the highly organized cucurbitacin gene cluster in the cucurbits. These results reveal that cucurbitacin biosynthesis has evolved convergently via different biosynthetic routes in different families rather than through divergence from an ancestral pathway. This study thus provides new insight into the mechanism of recurrent evolution and diversification of a plant defensive chemical.

Taste-testing tarsi: Gustatory receptors for glucosinolates in cabbage butterflies.

Taste-testing tarsi: Gustatory receptors for glucosinolates in cabbage butterflies.

Identification of a gustatory receptor tuned to sinigrin in the cabbage butterfly Pieris rapae.

Glucosinolates are token stimuli in host selection of many crucifer specialist insects, but the underlying molecular basis for host selection in these insects remains enigmatic. Using a combination of behavioral, electrophysiological, and molecular methods, we investigate glucosinolate receptors in the cabbage butterfly Pieris rapae. Sinigrin, as a potent feeding stimulant, elicited activity in larval maxillary lateral sensilla styloconica, as well as in adult medial tarsal sensilla. Two P. rapae gustatory receptor genes PrapGr28 and PrapGr15 were identified with high expression in female tarsi, and the subsequent functional analyses showed that Xenopus oocytes only expressing PrapGr28 had specific responses to sinigrin; when ectopically expressed in Drosophila sugar sensing neurons, PrapGr28 conferred sinigrin sensitivity to these neurons. RNA interference experiments further showed that knockdown of PrapGr28 reduced the sensitivity of adult medial tarsal sensilla to sinigrin. Taken together, we conclude that PrapGr28 is a gustatory receptor tuned to sinigrin in P. rapae, which paves the way for revealing the molecular basis of the relationships between crucifer plants and their specialist insects.