Pieris Rapae Research Articles

Efficacy and Cost Economics of Bio-Pesticides and Botanical Extracts Against Cabbage Butterly Pieris Brassicae Nepalensis Doubleday in Cauliflower Crop in Ilam, Nepal

A field experiment was conducted to compare the efficacy and profitability of using bio-pesticides and locally available botanical extracts for the management of cabbage butterfly Pieris Brassicae Nepalensis Doubleday for cauliflower production. The management study was established in a farmer’s field in Barhabasti, Ilam, Nepal. Eight different types of management treatments were deployed in a randomized complete block design (RCBD) with three replications. The treatments were i) Bacillus thuringensis var kurstaki (2 gm /lt) ii) Metarhizium Anisopliae (2.5 ml /lit) iii) Beauveria Bassiana (3 ml /lit) iv) Acorus calamus (1:5) v) Lantana camara (1:5) vi) Neem oil (1.5 ml /lt) vii) Cow urine (1:4) viii) Control. Results showed that bio-pesticides and botanical extracts were significantly superior over control. L. camara treated plots contained the lowest larval population compared to all other treatments. The order of effectiveness of the treatments based on the population reduction was L. camara > A. indica > A. calamus > Cow urine > M. Anisopliae > B. thuringiensis > B. Bassiana > control. The above treatments were also safe for natural enemies since there was a non-significant mortality effect of bio-pesticides on natural enemies. The highest benefit-cost ratio (2.36) was recorded in neem oil-treated plots that were superior to all other treatments. To summarize, this study can help to develop an IPM protocol for the sustainable management of cabbage butterflies in crucifer fields. SAARC J. Agric., 22(2): 127-138 (2024)

Radiocaesium and radiostrontium transfer to an insect herbivore and an insect detritivore through holometabolous development: A comparison between the cabbage butterfly (Pieris brassicae) and the black soldier fly (Hermetia illucens).

The presence of the long-lived radionuclides 137Cs and 90Sr in ecosystems is a major environmental concern because bioavailable forms of the radionuclides are readily transferred to living organisms. The present study investigated how holometabolous insect development influences the fate of radiocaesium and radiostrontium by examining the behaviour of tracers (134Cs and 84Sr) and stable elements during the larval feeding stage (21-23days old), the pupal stage, and the adult stage. We aimed to evaluate the degree to which an herbivore or a detritivore food chain could serve as transfer pathways to higher trophic levels in terms of accumulation potential, and during which stage of development the accumulation potential is highest. We used the Cabbage butterfly (Pieris brassicae) and the Black soldier fly (Hermetia illucens) as model insects in the herbivore food chain and the detritivore food chain, respectively. Both food chains showed similar patterns of radiocaesium transfer to the larvae, with concentration ratios of 0.26 to 1.15. Radiocaesium levels then gradually decreased during the transition from larva to adult. We also found strontium in the larvae of both model insects. However, while the transfer to P. brassicae was low and the majority of retained strontium was removed prior to the pupal stage, we found that strontium biomagnified in H. illucens larvae and pupae, showing high accumulation potentials. Overall, our results suggest that radiocaesium transfer to terrestrial holometabolous insects is predominantly determined by radiocaesium levels in their diet, whereas radiostrontium transfer is influenced by the insects' dietary need for calcium and the concentration of calcium in the diet.

Elevated Temperature Diminishes Reciprocal Selection in an Experimental Plant-Pollinator-Herbivore System.

The geographic mosaic of coevolution predicts reciprocal selection, the first step in coevolution, to vary with changing biotic and abiotic environmental conditions. Studying how temperature affects reciprocal selection is essential to connect effects of global warming on the microevolutionary patterns of coevolution to the ecological processes underlying them. In this study, we investigated whether temperature influenced reciprocal selection between a plant (Brassica rapa) and its pollinating butterfly herbivore (Pieris rapae). In two temperature environments (ambient and hot), we measured the phenotypes of plants and butterflies, their interactions and fitness, which we used to calculate reciprocal selection. We found a variety of traits involved in reciprocal selection in the ambient environment, but none in the hot environment. We provide experimental evidence that elevated temperature weakens reciprocal selection, which will help better predict the consequences of global warming for coevolution.

Scorpion insect neurotoxin LqhIT2 is a promising oral biopesticide: high-level preparation in Pichia pastoris and bioactivity assays.

Discovering insecticidal proteins with high activity and strict insect specificity and applying them to the biological control of insect pests is of great significance. Oral LqhIT2 has insecticidal activity, which most other insecticidal neurotoxin proteins do not have, but the large-scale preparation of the toxin is difficult and one of the obstacles to determining its anti-insect potential for biological control. In this study, the expression level of recombinant LqhIT2 (rLqhIT2) in Pichia pastoris was as high as 1.4 g/L under high-cell-density fermentation conditions. A purified rLqhIT2 at a final concentration of 0.5 ng/mL inhibited the proliferation of insect Sf9 cells, with typical insect cell oncosis observed, while 200 ng/mL rLqhIT2 was non-toxic to mammalian cells. The injection of silkworms caused the typical depressive symptoms of flaccid paralysis and death. At a dose of 1 μg/g body weight, 46.7% of the silkworms died within 48 h after injection, and their mortality rate was related to the injection dose. Feeding purified rLqhIT2 to fifth instar Pieris rapae larvae demonstrated its oral insecticidal activity, with a mortality rate 66.7% after 3 days of feeding at a concentration of 10 μg/cm2 cabbage leaf. The rLqhIT2 has high insect cells specificity and insecticidal activity when injected and or delivered orally, and may have better application prospects than other reported insect neurotoxins. We describe a method for large-scale production of functional rLqhIT2 by fed-batch fermentation using Pichia pastoris, which will further facilitate its application in biological control of agricultural insect pests. © 2024 Society of Chemical Industry.

Scope of Entomopathogenic Fungi in the Mustard Ecosystem: A Review

Mustard (Brassica juncea) is a versatile and widely cultivated plant in the Brassicaceae family. Among the primary factors impeding mustard yield, insect pest damage stands prominent. Insect pests such as mustard aphid (Lipaphis erysimi), mustard sawfly (Athalia lugens proxima), painted bug (Bagrada hilaris), diamondback moth (Plutella xylostella)and cabbage butterfly (Pieris brassicae) cause significant damage to mustard production. The excessive reliance on chemical insecticides to control these insect pests may negatively affect non-target organisms such as beneficial insects, pollinatorsand natural enemies of pests, thus disrupting ecosystem balance and posing risks to biodiversity. In pursuit of sustainable alternatives to broad-spectrum chemical pesticides, entomopathogens play a pivotal role in safer pest management strategies. These biological control agents, including various fungi, bacteria, virusesand nematodes, specifically target insect pests while being safer for non-target organisms and the environment. With more widespread commercialization, entomopathogenic fungi hold significant promise in bolstering integrated pest management practices.

Abundance and diversity of butterflies in urban green areas of Setif city (Algeria)

Butterflies are essential bioindicators of environmental health and play a critical role in maintaining ecosystem stability. Understanding their diversity and distribution in urban areas is crucial for biodiversity conservation. We conducted a survey of butterflies in Setif city to address the lack of information on butterfly diversity in Algerian urban environments. Butterflies were surveyed using pollard’s transect walking technique, with transects ranging from 500 m to 1 km. The observer recorded individuals within a 5x5x5 m area while walking each transect at a steady pace. Butterfly survey was conducted twice to three times each month from September 2021 to June 2023. In total, 726 individuals were collected, belonging to 32 species. The most abundant families were Pieridae and Nymphalidae, while Hesperiidae had the fewest species and individuals. Pieris rapae and Pararge aegeria were the most frequent and abundant species. The highest biodiversity indices were found in the Amusement Park (Shannon H = 2.43, Simpson 1-D = 0.867), and the lowest in Kitab Chahid Garden (Shannon H = 1.758) and Zenadia Forest (Simpson 1-D = 0.765). Equitability ranged from 0.67 to 0.88. Cluster analysis revealed two distinct groups of butterfly communities among the green areas. Pararge aegeria and Pieris rapae accounted for 50% of the differences between the green areas.

Butterfly species vary in sex‐specific sodium accumulation from larval diets

Abstract Sodium is essential for animals, and its heterogeneous distribution can cause a range of phenomena, from sodium‐seeking behaviours to impacting their performance. Although sodium content in soils and plants is relatively well documented, data for higher trophic levels are limited. Knowledge of the variation in sodium in lower trophic levels could have implications for understanding the behaviour and physiology of species at higher levels. We investigated the variation in tissue sodium concentration between males and females of four butterfly species. Puddling behaviour of Lepidoptera suggests sodium needs of males are generally greater than females, thus, we predicted males would accumulate more sodium than females on a given diet. Larvae were reared on plants (for Battus philenor, Chlosyne lacinia and Danaus plexippus) and an artificial diet (for Pieris rapae) under Low Na (no added sodium) and High Na (sodium added) conditions. Among species and sexes, we quantified and compared adult absolute tissue sodium concentrations and bioconcentration factors, which indicate net sodium accumulation or excretion relative to individuals' diets. On average, individuals on low‐sodium diets had higher bioconcentration values across all species. Male butterflies accumulated significantly higher sodium concentrations than females in two sodium treatments for B. philenor, and P. rapae and only in the High Na treatment for C. lacinia. However, in D. plexippus, individuals accumulate sodium in the High Na treatment, but males and females responded in the same way. Our study revealed sex‐ and species‐specific patterns of butterfly sodium accumulation, which could be linked to variations in behaviour and/or performance. Differences in sodium content across species have implications for variation in predation and trophic‐level interactions, an interesting avenue for future ecological and evolutionary research.

Important Insect Pests on Cabbage in Lao PDR

This study was conducted in Xiengkhouang province, Vientiane province, Saravane province, Champasak province, Vientiane Capital, and Plant Protection Center, from January to March 2017. The aims of study were to investigate to major insect pests on cabbage and compared the efficacy of Jeevatu, Jeevatu+botanical pesticide and chemical pesticide to control Diamondback moth in laboratory condition. The study was divided into two treatments: 1) survey important insect pests of cabbage in 3 purposive sampling areas (field)/village, 10 points/rai, and 3 cabbages/point to identify insect pests and survey the life cycle of Diamondback moth of cabbage, and 2) conduct the efficacy experiment of Jeevatu, Jeevatu+botanical pesticide and chemical pesticide to Diamondback moth in laboratory. The experiment was done by Completely Randomized Design (CRD) with 5 treatments and 4 replications. The survey showed that there are 8 species of insect pests on cabbage and the most important species is Diamondback moth (Plutella xylostella) which was found in all provinces that had been survey than followed by striped flea beetle (Phyllotreta striolata), cabbage aphid (Brevicoryne brassicae), cabbage butterfly (Pieris rapae), taro caterpillar (Spodoptera litura), cabbage webworm (Hellula undalis), cabbage looper (Trichoplasia ni) and flea beetle (phyllotreta cruciferae). Life cycle of Diamondback moth was investigated in that laboratory, and it showed that the total of life cycle took about 14-21 days that included 3-5 days for egg stage, 8-12 days for lavae stage, 3-4 days for pupae stage, and 13-31 days of bebeing mature. The efficacy of Jeevatu+Sugar apple leaf extracts, Jeevatu+Neem extracts, and Jeevatu with water for control Diamondback moth indicated that after 5 days sprayed, the mortality percentage was up to 90%, 80% and 57% respectively. For chemical sprayed for 2 days, the mortality percentage was up to 100%. The results of this study showed that the Jeevatu+botanical pesticide can be used as a substitute for substituting chemical in preventing the control Diamondback moth.

Caterpillar-parasitoid interactions: species-specific influences on host microbiome composition.

There is increasing evidence that host-parasitoid interactions can have a pronounced impact on the microbiome of host insects, but it is unclear to what extent this is caused by the host and/or parasitoid. Here, we compared the internal and external microbiome of caterpillars of Pieris brassicae and Pieris rapae parasitized by Cotesia glomerata or Cotesia rubecula with nonparasitized caterpillars. Additionally, we investigated the internal and external microbiome of the parasitoid larvae. Both internal and external bacterial densities were significantly higher for P. brassicae than P. rapae, while no differences were found between parasitized and nonparasitized caterpillars. In contrast, parasitism significantly affected the composition of the internal and external microbiome of the caterpillars and the parasitoid larvae, but the effects were dependent on the host and parasitoid species. Irrespective of host species, a Wolbachia species was exclusively found inside caterpillars parasitized by C. glomerata, as well as in the corresponding developing parasitoid larvae. Similarly, a Nosema species was abundantly present inside parasitized caterpillars and the parasitoid larvae, but this was independent of the host and the parasitoid species. We conclude that parasitism has pronounced effects on host microbiomes, but the effects depend on both the host and parasitoid species.

DNA Repair and Mutagenesis of ADP-Ribosylated DNA by Pierisin.

Pierisin is a DNA-targeting ADP-ribosyltransferase found in cabbage white butterfly (Pieris rapae). Pierisin transfers an ADP-ribosyl moiety to the 2-amino group of the guanine residue in DNA, yielding N2-(ADP-ribos-1-yl)-2'-deoxyguanosine (N2-ADPR-dG). Generally, such chemically modified DNA is recognized as DNA damage and elicits cellular responses, including DNA repair pathways. In Escherichia coli and human cells, it has been experimentally demonstrated that N2-ADPR-dG is a substrate of the nucleotide excision repair system. Although DNA repair machineries can remove most lesions, some unrepaired damages frequently lead to mutagenesis through DNA replication. Replication past the damaged DNA template is called translesion DNA synthesis (TLS). In vitro primer extension experiments have shown that eukaryotic DNA polymerase κ is involved in TLS across N2-ADPR-dG. In many cases, TLS is error-prone and thus a mutagenic process. Indeed, the induction of G:C to T:A and G:C to C:G mutations by N2-ADPR-dG in the hypoxanthine phosphoribosyltransferase gene mutation assay with Chinese hamster cells and supF shuttle vector plasmids assay using human fibroblasts has been reported. This review provides a detailed overview of DNA repair, TLS and mutagenesis of N2-ADPR-dG induced by cabbage butterfly pierisin-1.

Biochemical and genetic mechanisms in Pieris rapae (Lepidoptera: Pieridae) resistance under emamectin benzoate stress

Pieris rapae (Lepidoptera: Pieridae) poses a significant threat to Brassicaceae crops, leading to substantial losses annually. Repeated insecticide applications are widely used to protect crops and increase the resistance of P. rapae. Exploring the biochemical and molecular basis of insecticide tolerance in P. rapae is crucial for achieving effective insect suppuration and implementing resistance control strategies. In our research, emamectin benzoate (EBZ) resistance was developed in P. rapae strain through selective pressure over 15 generations. Moreover, the biochemical mechanisms underlying resistance to EBZ and its potential cross-resistance to other insecticides were studied. Additionally, the expression levels of cytochrome P450 (CYP450) and glutathione-s-transferase (GST) genes in P. rapae were quantitatively assessed upon exposure to EBZ using real-time PCR. Our data exhibited that the LC50 value of susceptible strain (Sus) and EBZ resistance strain (EBZ-R) were 0.009 and 8.09 mg/L, with a resistance ratio (RR) reaching 898.8-fold. The EBZ-R stain displayed notably low cross-resistance to lambda-cyhalothrin, spinetoram, and cypermethrin. However, it demonstrated a moderate level of cross-resistance to deltamethrin. Conversely, no cross-resistance was noted to chlorantraniliprole and indoxacarb. Notably, enzyme inhibitors of detoxification enzymes revealed that piperonyl butoxide (PBO) and diethyl maleate (DEM) enhanced the EBZ toxicity to the resistant strain, indicating the potential involvement of CYP450 and GST in avermectin resistance. A remarkable enhancement in CYP450 and GST activity was observed in the EBZ-R stain. CYP450 and GST genes are upregulated in the EBZ-R stain compared to the Sus strain, which serves as a basis for comprehending the mechanism behind P. rapae resistance to EBZ. The molecular docking analysis demonstrated that EBZ has a high binding affinity with CYP6AE120 and PrGSTS1 with docking energy values of −20.19 and −22.57 kcal/mol, respectively. Our findings offer valuable insights into crafting efficient strategies to monitor and manage resistance in P. rapae populations in Egypt.

ВИДОВИЙ СКЛАД І ЧИСЕЛЬНІСТЬ БІЛАНОВИХ (RHOPALOCERA, LEPIDOPTERA, PIERIDAE) В ЕНТОМОЛОГІЧНИХ КОЛЕКЦІЯХ ЗА 2021–2023 рр.

Species of Lepidoptera are specific indicators of the state of biotic communities and ecosystems, playing a crucial role in the functioning of phytocenoses and holding significant scientific, cognitive, and aesthetic value. Diurnal butterflies are highly vulnerable to anthropogenic influences and belong to one of the animal groups that is in danger of extinction. The article presents original data on the current status of the Pieridae family based on the analysis of collection materials gathered during April-October 2021–2023 in the Zakarpattia, Lviv, Volyn, Ivano-Frankivsk, Ternopil, Khmelnytskyi, Zhytomyr, and Dnipropetrovsk regions. Species identification was conducted under laboratory conditions according to scientific requirements. The list of species of this family was formed from taxa according to Nieukerken et al. (2011). Entomological collection of Lepidoptera was conducted in accordance with nature conservation legislation norms. It was established that in 2021, 8 species were identified (168 individuals), in 2022 – 5 species (71 individuals), and in 2023 – 6 species (84 individuals). The studied insects belong to 6 genera: Leptidea, Anthocharis, Pieris, Pontia, Colias, Gonepteryx. Based on the analysis of relative abundance, it was determined that Pieris rapae was the most abundant species throughout the studied years, while Pieris brassicae, Pieris napi, Colias hyale, and Gonepteryx rhamni were common species, and Leptidea sinapis, Anthocharis cardamines, Pontia daplidice, and Colias croceus were rare. For a detailed study of the Pieridae family and conducting comprehensive ecological-faunistic insect identification, we plan to conduct annual entomological surveys of fauna of Ukraine. These data can be used for the further analysis of the changes of species diversity of this family taking into account biodiversity conservation.

Oviposition strategies in Pieridae butterflies and the role of an egg-killing plant trait therein.

Most herbivorous insects are host-plant specialists that evolved detoxification mechanisms to overcome their host plant's toxins. In the evolutionary arms-races between Pieridae butterflies and Brassicaceae plants, some plant species have evolved another defence against the pierids: egg-killing. Underneath the eggs, leaves develop a so-called hypersensitive response (HR)-like cell death. Whether some butterflies have evolved oviposition strategies to counter-adapt against egg-killing remains to be studied. In this study, we assessed the oviposition site location of Pieridae butterflies on their natural host plants. We described the plant tissue on which we located the eggs of the most common Pieridae in the Netherlands: Gonepteryx rhamni, Anthocharis cardamines, Pieris rapae, P. napi, P. brassicae and P. mannii. Additionally, we assessed expression of HR-like cell death in response to the deposited butterfly eggs. We found that both A. cardamines and G. rhamni mainly oviposited on the floral stem and the branch, respectively, and oviposited on host plants from lineages not expected to kill pierid eggs. Accordingly, no HR-like cell death was seen. All Pieris eggs found were located on leaves of their host, the only tissue found to express HR-like cell death. Furthermore, each Pieris species was found to at least occasionally oviposit on Brassica nigra. This was the only plant species in this survey that expressed HR-like cell death in response to the eggs of P. rapae, P. napi and P. brassicae. Our observations demonstrate that HR-like cell death remains an effective defence strategy against these Pieris species and as such did not find evidence for the hypothesized counterstrategies. Surveying certain key species and disentangling the micro-evolution of oviposition strategies within a species would allow us to further investigate potential counter-adaptations that evolved against HR-like cell death. This study provides the basis for further investigation of potential counter-adaptations to egg-killing defences.

Too hot to handle: temperature-induced plasticity influences pollinator behaviour and plant fitness.

Increased temperature can induce plastic changes in many plant traits. However, little is known about how these changes affect plant interactions with insect pollinators and herbivores, and what the consequences for plant fitness and selection are. We grew fast-cycling Brassica rapa plants at two temperatures (ambient and increased temperature) and phenotyped them (floral traits, scent, colour and glucosinolates). We then exposed plants to both pollinators (Bombus terrestris) and pollinating herbivores (Pieris rapae). We measured flower visitation, oviposition of P. rapae, herbivore development and seed output. Plants in the hot environment produced more but smaller flowers, with lower UV reflectance and emitted a different volatile blend with overall lower volatile emission. Moreover, these plants received fewer first-choice visits by bumblebees and butterflies, and fewer flower visits by butterflies. Seed production was lower in hot environment plants, both because of a reduction in flower fertility due to temperature and because of the reduced visitation of pollinators. The selection on plant traits changed in strength and direction between temperatures. Our study highlights an important mechanism by which global warming can change plant-pollinator interactions and negatively impact plant fitness, as well as potentially alter plant evolution through changes in phenotypic selection.

Unraveling the efficacy and reproductive potential of two native isolates of entomopathogenic nematodes against cabbage butterfly (Pieris brassicae (L.) (Lepidoptera: Pieridae)

Unraveling the efficacy and reproductive potential of two native isolates of entomopathogenic nematodes against cabbage butterfly (Pieris brassicae (L.) (Lepidoptera: Pieridae)

Pierisin, Cytotoxic and Apoptosis-Inducing DNA ADP-Ribosylating Protein in Cabbage Butterfly.

Pierisin-1 was serendipitously discovered as a strong cytotoxic and apoptosis-inducing protein from pupae of the cabbage butterfly Pieris rapae against cancer cell lines. This 98-kDa protein consists of the N-terminal region (27 kDa) and C-terminal region (71 kDa), and analysis of their biological function revealed that pierisin-1 binds to cell surface glycosphingolipids on the C-terminal side, is taken up into the cell, and is cleaved to N- and C-terminal portions, where the N-terminal portion mono-ADP-ribosylates the guanine base of DNA in the presence of NAD to induce cellular genetic mutation and apoptosis. Unlike other ADP-ribosyltransferases, pieisin-1 was first found to exhibit DNA mono-ADP-ribosylating activity and show anti-cancer activity in vitro and in vivo against various cancer cell lines. Pierisin-1 was most abundantly produced during the transition from the final larval stage to the pupal stage of the cabbage butterfly, and this production was regulated by ecdysteroid hormones. This suggests that pierisn-1 might play a pivotal role in the process of metamorphosis. Moreover, pierisin-1 could contribute as a defense factor against parasitization and microbial infections in the cabbage butterfly. Pierisin-like proteins in butterflies were shown to be present not only among the subtribe Pierina but also among the subtribes Aporiina and Appiadina, and pierisin-2, -3, and -4 were identified in these butterflies. Furthermore, DNA ADP-ribosylating activities were found in six different edible clams. Understanding of the biological nature of pierisin-1 with DNA mono-ADP-ribosylating activity could open up exciting avenues for research and potential therapeutic applications, making it a subject of great interest in the field of molecular biology and biotechnology.

Resistance and susceptibility of different Barbarea (Brassicaceae) species and types to cabbage whitefly (Hemiptera: Aleyrodidae) and cabbage white butterfly (Lepidoptera: Pieridae)

Several Barbarea spp. (Brassicaceae) have been tested as trap crops for the diamondback moth Plutella xylostella L. (Lepidoptera: Plutellidae). The use of trap crops can be affected by their susceptibility to other pests, especially if the purpose is to reduce insecticide use. Barbarea rupicola Moris, B. verna (Mill.) Asch., and B. vulgaris Aiton (types G and P) (Brassicaceae) were tested for their susceptibility to the cabbage whitefly Aleyrodes proletella L. (Hemiptera: Aleyrodidae). The percentage of plants showing infestation by cabbage whiteflies ranged from 50% in G-type B. vulgaris and 8.3% in B. verna to no infestation at all in B. rupicola and P-type B. vulgaris. On the other hand, 95.8% of P-type plants showed symptoms of powdery mildew, Erysiphe cruciferarum Opiz ex L. Junell (Erysiphales: Erysiphaceae), while the G type and the other Barbarea spp. were unaffected by this pathogen. Additionally, the G and P types were used in two-choice oviposition preference tests to compare their attractiveness to the small white butterfly Pieris rapae L. (Lepidoptera: Pieridae). No significant differences in total oviposition per plant were found between the two types, but within-plant differences show that the small white butterfly prefers to oviposit on the adaxial leaf side in the P type. This study indicates that in locations where the cabbage whitefly is an economic pest, B. verna, which can also be used as a dead-end trap crop for the diamondback moth, could be chosen over G-type B. vulgaris.

Butterfly wing-inspired microstructured film with high reflectivity for efficient passive radiative cooling

Radiative cooling is a passive cooling technology that radiates heat to outer space without any energy input thus such technology is of great significance for alleviating environmental pollution and consumption of energy. However, achieving cooling during the daytime normally requires a series of complex structural designs that are economically inefficient and unscalable fabrication process. In this work, inspired by the nanostructure of Pieris rapae butterfly wings, we fabricate a double-layered polymeric film with a bead-like structure which can scatters incident light intensely for passive radiative cooling. Through optical characterization, it was demonstrated that the film can provide a high solar reflectivity of ∼92.4 % and a high atmospheric window emissivity of ∼93.2 %. In field tests, the film can achieve a maximum temperature drop of 6.5 °C and an average temperature drop of 3.8 °C under direct sunlight, and theoretically producing an effective cooling power of 123.8 W m−2. The as-prepared film could be fabricated through a low-cost template process, and our work presents a new approach to the application of radiative cooling technology in the field of building cooling.

Quantifying direct and indirect effects of early‐season herbivory on reproduction across four brassicaceous plant species

Abstract Insect herbivores can directly affect plant reproduction by feeding on reproductive tissues, or indirectly by feeding on vegetative tissues for which plants are unable to compensate. Additionally, early arriving herbivores may have cascading effects on plant reproduction by altering the later arriving community. However, the dynamic interplay between plant development and the assembly of herbivore communities remains underexplored. Hence, it is unclear whether non‐outbreak levels of ambient herbivory early in the development of plants can impact plant fitness and to what extent these effects are mediated through changes in plant development and subsequent herbivory. By excluding the herbivore community in an exclosure experiment and by manipulating early‐season herbivory in a common garden field experiment replicated across four Brassicaceae species and 2 years, we tested whether early‐season herbivory by caterpillars (Pieris rapae) or aphids (Myzus persicae) affected development, reproduction, and the herbivore communities associated with individual plants. In addition, we tested a causal hypothesis to assess the relative importance and temporal interplay between variation in herbivore communities and variation in plant development in determining plant reproduction. Early‐season herbivory affected plant reproduction in the exclosure experiment, with effects being highly dependent on the plant species, the herbivore species and the year. However, we found no such effects in the field experiment. The exploratory path analysis indicated that variation in plant reproduction is best predicted by variation in plant development, explaining 80% of the total effect on seed production. This suggests early‐season herbivory had limited effects on later plant development, and plants were able to attenuate the impact of early‐season herbivory. However, no clear compensatory mechanism could be identified. While early‐season herbivory has the potential to affect plant reproduction through changes in plant development or the subsequent development of the associated community, these effects were small and varied across closely related species. This suggests that plant species may be exposed to different levels of natural selection by early‐season herbivores through plant‐ or community‐mediated effects on reproduction. Read the free Plain Language Summary for this article on the Journal blog.

Resource-based trade-offs and the adaptive significance of seasonal plasticity in butterfly wing melanism.

Phenotypic plasticity is the ability of an organism to alter its phenotype in response to environmental cues. This can be adaptive if the cues are reliable predictors of impending conditions and the alterations enhance the organism's ability to capitalize on those conditions. However, since traits do not exist in isolation but as part of larger interdependent systems of traits (phenotypic integration), trade-offs between correlated plastic traits can make phenotypic plasticity non- or maladaptive. We examine this problem in the seasonally plastic wing melanism of a pierid (Order Lepidoptera, Family Pieridae) butterfly, Pieris rapae L. Several wing pattern traits are more melanized in colder than in warmer seasons, resulting in effective thermoregulation through solar absorption. However, other wing pattern traits, the spots, are less melanized during colder seasons than in warmer seasons. Although spot plasticity may be adaptive, reduced melanism of these spots could also be explained by resource-based trade-offs. Theory predicts that traits involved in resource-based trade-offs will be positively correlated when variation among individuals in resource acquisition is greater than variation among individuals in resource allocation strategies, and negatively correlated when variation in allocation is greater than variation in acquisition. Using data from both field studies and laboratory studies that manipulate dietary tyrosine, a melanin precursor, we show that when allocation to thermoregulatory melanism (ventral hindwing, and basal dorsal fore- and hindwing "shading") varies substantially this trait is negatively correlated with spot melanism. However, when there is less variation in allocation to thermoregulatory melanism we find these traits to be positively correlated; these findings are consistent with the resource-based trade-off hypothesis, which may provide a non- or maladaptive hypothesis to explain spot plasticity. We also show that increased dietary tyrosine results in increased spot melanism under some conditions, supporting the more general idea that melanism may involve resource-based costs.