Small Cabbage White Butterfly Research Articles

Extremely high relative growth rate makes the cabbage white, Pieris rapae, a global pest with highly abundant and migratory nature

The small cabbage white butterfly, Pieris rapae, is an extraordinarily abundant migratory pest of cabbage that causes severe damage worldwide without known reasons. I here show that the average relative growth rate (RGR: the ratio of the daily increase of biomass to total biomass) of herbivore (Gh; an indicator of the growth speed of herbivore) of P. rapae on cabbage during the larval period is larger by far than those of all other insect–plant pairs tested. It exceeds 1.15 (/day),—meaning that the biomass more than doubles each day—compared to 0.1–0.7 for most insect–plant pairs, including that of Pieris melete, a sibling of P. rapae which never becomes a pest of cabbage. My data further showed the RGR in the larval stage (larval Gh), positively correlates with abundance and/or migratoriness of insect herbivores. These results together with my mathematical food web model suggest that the extraordinarily high larval Gh of P. rapae is the primary reason for its ubiquitously severe pest status accompanied with its abundance and migratoriness, and that the RGR of herbivores, Gh, characterizing the plant–herbivore interface at the bottom of the food webs is an important factor affecting whole ecosystems, including animal abundance, fauna size, plant damage levels, competitiveness among herbivorous species, determination of hostplant, invasiveness, and the evolution of animal traits involved in the so-called r/K strategy, such as migratoriness. Knowledge about Gh will be crucial to controlling pests and improving the negative effects of human activity on ecosystems including faunal decline (or defaunation).

Global invasion history of the agricultural pest butterfly Pieris rapae revealed with genomics and citizen science

The small cabbage white butterfly, Pieris rapae, is a major agricultural pest of cruciferous crops and has been introduced to every continent except South America and Antarctica as a result of human activities. In an effort to reconstruct the near-global invasion history of P. rapae, we developed a citizen science project, the "Pieris Project," and successfully amassed thousands of specimens from 32 countries worldwide. We then generated and analyzed nuclear (double-digest restriction site-associated DNA fragment procedure [ddRAD]) and mitochondrial DNA sequence data for these samples to reconstruct and compare different global invasion history scenarios. Our results bolster historical accounts of the global spread and timing of P. rapae introductions. We provide molecular evidence supporting the hypothesis that the ongoing divergence of the European and Asian subspecies of P. rapae (∼1,200 y B.P.) coincides with the diversification of brassicaceous crops and the development of human trade routes such as the Silk Route (Silk Road). The further spread of P. rapae over the last ∼160 y was facilitated by human movement and trade, resulting in an almost linear series of at least 4 founding events, with each introduced population going through a severe bottleneck and serving as the source for the next introduction. Management efforts of this agricultural pest may need to consider the current existence of multiple genetically distinct populations. Finally, the international success of the Pieris Project demonstrates the power of the public to aid scientists in collections-based research addressing important questions in invasion biology, and in ecology and evolutionary biology more broadly.

Black and Garlic Mustard Plants Are Highly Suitable for the Development of Two Native Pierid Butterflies.

In multivoltine insects that oviposit and develop on short-lived plants, different herbivore generations across a growing season often exploit different plant species. Here, we compare the development time, pupal mass, and survival of two closely related oligophagous herbivore species on two species of brassicaceous plants that grow in different habitats and which exhibit little overlap in temporal growth phenology. In central Europe, the green-veined white butterfly, Pieris napi L., is bivoltine, whereas the small cabbage white butterfly, Pieris rapae L., has two to three generations a year. Moreover, P. napi is primarily found in moist, open (e.g., meadow), and forest habitats, whereas P. rapae prefers drier, open habitats. Both butterflies were reared on Garlic mustard (Alliaria petiolata), which is shade-tolerant and grows early in spring in forest undergrowth, and Black mustard (Brassica nigra), which prefers open disturbed habitats and is most common in summer. Both host plant species differ in other traits such as secondary chemistry. We hypothesized that, owing to habitat preference, P. napi would develop equally well on both plants but that P. rapae would perform better on B. nigra. The results provide partial support for this hypothesis, as both herbivores performed equally well on A. petiolata and B. nigra. However, there were differences in these parameters that were species-specific: on both plants P. rapae developed faster and had larger pupae than P. napi. Our results show that specialized herbivores can exploit different species of related plants that grow at different times of the season, enabling them to have multiple generations.

Differentially expressed genes linked to natural variation in long-term memory formation in Cotesia parasitic wasps.

Even though learning and memory are universal traits in the Animal Kingdom, closely related species reveal substantial variation in learning rate and memory dynamics. To determine the genetic background of this natural variation, we studied two congeneric parasitic wasp species, Cotesia glomerata and C. rubecula, which lay their eggs in caterpillars of the large and small cabbage white butterfly. A successful egg laying event serves as an unconditioned stimulus (US) in a classical conditioning paradigm, where plant odors become associated with the encounter of a suitable host caterpillar. Depending on the host species, the number of conditioning trials and the parasitic wasp species, three different types of transcription-dependent long-term memory (LTM) and one type of transcription-independent, anesthesia-resistant memory (ARM) can be distinguished. To identify transcripts underlying these differences in memory formation, we isolated mRNA from parasitic wasp heads at three different time points between induction and consolidation of each of the four memory types, and for each sample three biological replicates, where after strand-specific paired-end 100 bp deep sequencing. Transcriptomes were assembled de novo and differential expression was determined for each memory type and time point after conditioning, compared to unconditioned wasps. Most differentially expressed (DE) genes and antisense transcripts were only DE in one of the LTM types. Among the DE genes that were DE in two or more LTM types, were many protein kinases and phosphatases, small GTPases, receptors and ion channels. Some genes were DE in opposing directions between any of the LTM memory types and ARM, suggesting that ARM in Cotesia requires the transcription of genes inhibiting LTM or vice versa. We discuss our findings in the context of neuronal functioning, including RNA splicing and transport, epigenetic regulation, neurotransmitter/peptide synthesis and antisense transcription. In conclusion, these brain transcriptomes provide candidate genes that may be involved in the observed natural variation in LTM in closely related Cotesia parasitic wasp species.

Does stem color affect the selection of host plants by the small cabbage white butterflyPieris rapae?

The effects of Brassica rapa stem color on the selection of host plants by Pieris rapae were investigated using choice tests between seedlings with reddish-purple, anthocyanin-containing stems and seedlings with light-green, anthocyaninless stems. The first landing response and the collective as well as the individual egg-laying behavior of P. rapae female butterflies to the reddish-purple-stemmed seedlings were comparable to the responses to the light-green-stemmed plants. These results demonstrate that stem anthocyanins do not play a significant role in host plant selection.

Development of a generalist predator, Podisus maculiventris, on glucosinolate sequestering and nonsequestering prey.

Insect herbivores exhibit various strategies to counter the toxic effects of plant chemical defenses. These strategies include the detoxification, excretion, and sequestration of plant secondary metabolites. The latter strategy is often considered to provide an additional benefit in that it provides herbivores with protection against natural enemies such as predators. Profiles of sequestered chemicals are influenced by the food plants from which these chemicals are derived. We compared the effects of sequestration and nonsequestration of plant secondary metabolites in two specialist herbivores on the development of a generalist predator, Podisus maculiventris. Profiles of glucosinolates, secondary metabolites characteristic for the Brassicaceae, are known to differ considerably both inter- and intraspecifically. Throughout their immature (=nymphal) development, the predator was fed on larval stages of either sequestering (turnip sawfly, Athalia rosae) or nonsequestering (small cabbage white butterfly, Pieris rapae) prey that in turn had been feeding on plants originating from three wild cabbage (Brassica oleracea) populations that have previously been shown to differ in their glucosinolate profiles. We compared survival, development time, and adult body mass as parameters for bug performance. Our results show that sequestration of glucosinolates by A. rosae only marginally affected the development of P. maculiventris. The effects of plant population on predator performance were variable. We suggest that sequestration of glucosinolates by A. rosae functions not only as a defensive mechanism against some predators, but may also be an alternative way of harmlessly dealing with plant allelochemicals.

Insects Associated With Tea and Their Identification at Ntri (Shinkiari) Mansehra, Pakistan

Tea plants are visited by different types of insects including tea pests and pollinator. The objective of the study was to identify tea associated insects in National Tea Research Institute (NTRI), Mansehra, Pakistan during April-June 2012. A collection of tea associated insects was made during April-June 2012 in Tea Experimental Garden (TEG), NTRI, Mansehra, Pakistan. A total of 128 samples were collected from TEG randomly. During the present research, 10 species were identified. Species collected were brush-footed butterfly, Argynnis hyperbius (Linnaeus, 1763); painted lady, Vanessa cardui (Linnaeus, 1758), Lucerne butterfly, Colias electo (Linnaeus, 1763)( Nymphalidae); small cabbage white butterfly, Pieris rapae (Linnaeus, 1758), white cabbage butterfly, Pieris brassicae (Linnaeus, 1758)( Pieridae); Asiatic honey bee, Apis cerana Fabricius, 1793, Western honey bee, Apis mellifera Linnaeus, 1758(Apidae); seven-spot ladybird Coccinella septempunctata (Linnaeus, 1758)( Coccinellidae); blue marsh hawk Orthetrum glaucum (Brauer, 1865), Crimson-tailed marsh hawk, Orthetrum pruinosum neglectum (Rambur, 1842)( Libellulidae). Different numbers of individuals were collected of each species. Seventeen individuals of P. brassicae, 16 of C. septempunctata, 15 of P. rapae, 14 of C. electo, 13 of V. cardui and A. cerana, 10 of A. mellifera, 9 of O. pruinosum neglectum and 7 of O. glaucum.It is concluded that there is a diversity to explain tea associated insects in NTRI, Mansehra, Pakistan.

New Record of Brachymeria albicrus (Klug) (Hymenoptera: Chalcididae), A Pupal Parasitoid of the Cabbage White Butterfly, Pieris rapae (linnaeus) from Iran

Small cabbage white butterfly, Pieris rapae is the most important insect pest of the plants belonging to family Brassicaceae. In order to identify its parasitoids, sampling was made in the cauliflower fields of southern Tehran from June until October 2011. The pupae were collected from fields and then reared under controlled conditions of 27°C, 60±10% Rh and 14L:10D photoperiod until the emergence of parasitoid adults. These parasitoids were put in alcohol 75°. One parasitoid wasp specimen was collected from the pupal samples. This parasitoid was identified as Brachymeria albicrus (Klug) (Hymenoptera: Chalcididae). This species is a new host record from P. rapae and distribution record from Tehran for the fauna of Iran.

Onset of herbivore-induced resistance in systemic tissue primed for jasmonate-dependent defenses is activated by abscisic acid

In Arabidopsis, the MYC2 transcription factor on the one hand and the AP2/ERF transcription factors ORA59 and ERF1 on the other hand regulate distinct branches of the jasmonic acid (JA) signaling pathway in an antagonistic fashion, co-regulated by abscisic acid (ABA) and ethylene, respectively. Feeding by larvae of the specialist herbivorous insect Pieris rapae (small cabbage white butterfly) results in activation of the MYC-branch and concomitant suppression of the ERF-branch in insect-damaged leaves. Here we investigated differential JA signaling activation in undamaged systemic leaves of P. rapae-infested plants. We found that the MYC2 transcription factor gene was induced both in the local insect-damaged leaves and the systemic undamaged leaves of P. rapae-infested Arabidopsis plants. However, in contrast to the insect-damaged leaves, the undamaged tissue did not show activation of the MYC-branch marker gene VSP1. Comparison of the hormone signal signature revealed that the levels of JA and (+)-7-iso-jasmonoyl-L-isoleucine raised to similar extents in locally damaged and systemically undamaged leaves, but the production of ABA and the JA precursor 12-oxo-phytodienoic acid was enhanced only in the local herbivore-damaged leaves, and not in the distal undamaged leaves. Challenge of undamaged leaves of pre-infested plants with either P. rapae larvae or exogenously applied ABA led to potentiated expression levels of MYC2 and VSP1, with the latter reaching extremely high expression levels. Moreover, P. rapae-induced resistance, as measured by reduction of caterpillar growth on pre-infested plants, was blocked in the ABA biosynthesis mutant aba2-1, that was also impaired in P. rapae-induced expression of VSP1. Together, these results suggest that ABA is a crucial regulator of herbivore-induced resistance by activating primed JA-regulated defense responses upon secondary herbivore attack in Arabidopsis.

Study on the Effect of Allylisothiocyanate Formulations on Three Lepidopterous Insect Larvae, the Diamond Back Moth, <i>Plutella xylostella</i> (L.), the Small Cabbage White Butterfly, <i>Pieris rapae</i> (L.) and Tobacco Cut Worm, <i>Spodoptera litura</i> Fabr

Problem statement: The toxicity of seven of Allylisothiocyanate (AITC) formulations, AITC pure and in mixture with cypermethrin and chlorpyrifos, was evaluated using spray application and fumigation method against the diamondback moth, Plutella xylostella (L.), the small cabbage white butterfly, Pieris rapae (L.) and the tobacco cut worm, Spodoptera litura Fabr. Approach: Response varied according to insect species, specific formulation and AITC application rates. Results: Fumigant toxicity of the oil based on 9 h exposure was evaluated against the three insect larvae, the diamond back moth, P. xylostella larvae were more susceptible followed by tobacco cut worm, S. litura and cabbage white, P. rapae larvae. To P. xylostella larvae, LC50 value was 1.5 μL L-1 air, S. litura larvae (LC50, 1.8 μL L-1 air) and P. rapae larvae (LC50, 2.0 μL L-1 air). These three insect larvae were killed after 9 h exposure to a dose of 4.3 μL L-1 air of the oil, showed no significance difference with that of phosphine (40 μg L-1 air) a recommended dose. On the other hand, on the spray application bioassays, mortality data counted 72h after treatment, the P. rapae larvae were most susceptible to AITC formulations followed by S. litura larvae and P. xylostella larvae. LC50 values, to P. xylostella larvae, HJ(A) and HJ(B) were the most potent toxicant (33 mg L-1) and (46 mg L-1) respectively, while the least toxic was HJ(C) (556 mg L-1). To S. litura larvae, HJ(B) and HJ(A) were the most efficient (10 mg L-1) and (22 mg L-1) respectively, while HJ(D) (LC50, 385 mg L-1) was found to be the least toxic. The both of HJ (B) and HJ (C) had similar insecticidal activity (LC50, 8 mg L-1) to Pieris rapae larvae followed by HD (B) (LC50, 22 mg L-1) and HD (A) (LC50, 82 mg L-1). Conclusion/Recommendations: It was concluded that the AITC oil showed promise findings and may be a good alternative to old fumigant “phosphine”. The others were found efficient on the spray application bioassays but the mixture of AITC with cypermethrin especially HJ (A) and HJ (B) were found to be better than AITC mixed with chlorpyrifos and AITC pure. So they can be used in the field of crop protection as safer and potential components of an integrated pest management strategy, especially allylisothiocyanate is considered fully biodegradable, less toxic and many cruciferous vegetables daily consumed by humans.

Chemical espionage on species-specific butterfly anti-aphrodisiacs by hitchhiking Trichogramma wasps

Parasitic wasps employ a wide range of chemical cues to find their hosts. Very recently, we discovered how 2 closely related egg parasitoids, Trichogramma brassicae and Trichogramma evanescens, exploit the anti-aphrodisiac pheromone benzyl cyanide of one of their hosts, the gregarious large cabbage white butterfly Pieris brassicae that deposits a clutch of more than 20 eggs per oviposition bout. The pheromone is transferred by male butterflies to females during mating to enforce female monogamy. On detecting the anti-aphrodisiac, the tiny parasitic wasps ride on a mated female butterfly to a host plant and then parasitize her freshly laid eggs. The present study demonstrates that both wasp species similarly exploit the anti-aphrodisiac mixture of methyl salicylate and indole of another host, the more common solitary small cabbage white butterfly Pieris rapae that deposits only one egg at a time. Interestingly, this behavior is innate in T. brassicae, whereas T. evanescens learns it after one successful ride on a mated female butterfly. Moreover, we show that the wasps only respond to the anti-aphrodisiacs of the 2 cabbage white butterflies when the ubiquitous compounds are part of a complete mated female odor blend. Obviously, parasitic wasps use the sophisticated espionage-and-ride strategy to find eggs of different gregarious and solitary host species. From the wasps’ perspective there seems to be a trade-off between the abundance and egg-laying behavior of the butterflies. Our findings suggest that Pieris butterflies are under strong selective pressure to minimize the use of an anti-aphrodisiac.

Responses of disparate phenotypically-plastic, melanin-based traits to common cues: limits to the benefits of adaptive plasticity?

The evolution of perfect adaptive phenotypic plasticity of a given trait may be influenced by, among other things, phenotypic costs associated with the expression of a given trait value, relative to alternative trait values. One potential cause of such phenotypic costs is the allocation of limited resources to multiple traits. When multiple traits rely on the same resource, trait values for one adaptively plastic trait might be unavoidably associated with maladaptive trait values for other traits. I address this problem in three traits of Pieris rapae L. (the small cabbage white butterfly) that all rely on the pigment melanin and are adaptively plastic, but have very different functions: wing pattern, immune defense, and pupal color. Cool, short-day rearing conditions simultaneously increased total wing melanization and decreased a melanin-based immune response in females, consistent with predictions. However, cool, short days also reduced the melanin-based immune response in males, despite little effect on male wing melanization. Furthermore, contrary to predictions, these patterns were not altered by differences in dietary resources. Finally, dark-colored rearing backgrounds during pupation substantially increased pupal melanization in both sexes, but was not associated with differences in wing melanization. These results offer only mixed support for the hypothesis of melanin-based trade offs as a source of phenotypic costs to adaptive plasticity in these traits. However, patterns of sexual dimorphism for these traits suggest trade offs might be at work at another level: relative to males, females have consistently more heavily melanized wings but less heavily melanized pupae and immune responses. The reduced immune response under cool, short-day conditions may also have implications for the evolutionary ecology of these butterflies.

Chemosensory basis of behavioural plasticity in response to deterrent plant chemicals in the larva of the Small Cabbage White butterfly Pieris rapae

Behavioural and electrophysiological responsiveness to three chemically different secondary plant substances was studied in larvae of Pieris rapae L. (Lepidoptera: Pieridae). Three groups of caterpillars were studied that during their larval development were exposed to different rearing diets: an artificial diet or one of two host-plants, cabbage, Brassica oleracea, or nasturtium, Tropaeolum majus. In dual-choice leaf disc assays, caterpillars reared on cabbage were strongly deterred by the phenolic chlorogenic acid, the flavonol glycoside naringin and the alkaloid strychnine. However, behavioural plasticity was found in caterpillars reared on nasturtium or artificial diet in that these did not discriminate against chlorogenic acid. Caterpillars reared on the artificial diet were also significantly less sensitive to naringin and strychnine in the behavioural assay. Electrophysiological studies of the maxillary sensilla styloconica revealed that the deterrent neuron in the medial sensillum, but not in the lateral sensillum, of cabbage-reared caterpillars was more sensitive than the same neuron type of caterpillars reared on nasturtium or artificial diet. We conclude that (1) the diet-induced behavioural habituation to deterrents can at least partly be explained by chemosensory desensitisation of a generalist type of maxillary deterrent neuron; (2) behavioural cross-habituation to the three structurally diverse deterrent compounds can be traced back to cross-sensitivity for these compounds in the same gustatory neuron.

Natural selection and genetic differentiation of behaviour between parasitoids from wild and cultivated habitats

Differences in behaviour between individuals in populations living in different environments may result from evolution proceeding differently in each population. The parasitoid wasp Cotesia glomerata (L.) (Hymenoptera: Braconidae) parasitizes early instar larvae of butterflies in the family Pieridae. In the study area the only host of C. glomerata is the Small Cabbage White Butterfly [Pieris rapae (L.) (Lepidoptera: Pieridae)], which feeds on cruciferous host plants in a variety of habitats. The behaviour of this parasitoid wasp collected from two habitat types (wild and agricultural) was observed in a reciprocal transplant-style experiment in a greenhouse. Differences in behaviour between wasp sources and test habitat type were analysed using canonical analysis in multivariate analysis of variance. Directional selection on parasitoid behaviour in each test habitat type was estimated by regressing the relative rate of parasitism (a measure of relative fitness) on the behavioural character state. We found that there is genetic differentiation of behaviour between wasps from wild and cultivated habitats and that a different set of behaviours is associated with short-term fitness within models of each source habitat. There was no evidence of local adaptation of wasps to either habitat.

A review of the pre‐oviposition behaviour of small cabbage white butterfly, Pieris rapae(lepidoptera: Pieridae)

SummaryThis paper reviews the literature concerning the ovipositional behaviour of Pieris rapae (small cabbage white butterfly) and where appropriate considers results from studies involving other butterflies. The paper considers searching behaviour, stimuli utilised in host plant finding and identification and concludes with a general section on the role of learning and prior experience in ovipositional behaviour.