Cabbage White Butterfly Pieris Brassicae Research Articles

Oviposition Preference for Young Plants by the Large Cabbage Butterfly (Pieris brassicae) Does not Strongly Correlate with Caterpillar Performance

The effects of temporal variation in the quality of short-lived annual plants on oviposition preference and larval performance of insect herbivores has thus far received little attention. This study examines the effects of plant age on female oviposition preference and offspring performance in the large cabbage white butterfly Pieris brassicae. Adult female butterflies lay variable clusters of eggs on the underside of short-lived annual species in the family Brassicaceae, including the short-lived annuals Brassica nigra and Sinapis arvensis, which are important food plants for P. brassicae in The Netherlands. Here, we compared oviposition preference and larval performance of P. brassicae on three age classes (young, mature, and pre-senescing) of B. nigra and S. arvensis plants. Oviposition preference of P. brassicae declined with plant age in both plant species. Whereas larvae performed similarly on all three age classes in B. nigra, preference and performance were weakly correlated in S. arvensis. Analysis of primary (sugars and amino acids) and secondary (glucosinolates) chemistry in the plant shoots revealed that differences in their quality and quantity were more pronounced with respect to tissue type (leaves vs. flowers) than among different developmental stages of both plant species. Butterflies of P. brassicae may prefer younger and smaller plants for oviposition anticipating that future plant growth and size is optimally synchronized with the final larval instar, which contributes >80% of larval growth before pupation.

Egg Laying of Cabbage White Butterfly (Pieris brassicae) on Arabidopsis thaliana Affects Subsequent Performance of the Larvae

Plant resistance to the feeding by herbivorous insects has recently been found to be positively or negatively influenced by prior egg deposition. Here we show how crucial it is to conduct experiments on plant responses to herbivory under conditions that simulate natural insect behaviour. We used a well-studied plant – herbivore system, Arabidopsis thaliana and the cabbage white butterfly Pieris brassicae, testing the effects of naturally laid eggs (rather than egg extracts) and allowing larvae to feed gregariously as they do naturally (rather than placing single larvae on plants). Under natural conditions, newly hatched larvae start feeding on their egg shells before they consume leaf tissue, but access to egg shells had no effect on subsequent larval performance in our experiments. However, young larvae feeding gregariously on leaves previously laden with eggs caused less feeding damage, gained less weight during the first 2 days, and suffered twice as high a mortality until pupation compared to larvae feeding on plants that had never had eggs. The concentration of the major anti-herbivore defences of A. thaliana, the glucosinolates, was not significantly increased by oviposition, but the amount of the most abundant member of this class, 4-methylsulfinylbutyl glucosinolate was 1.8-fold lower in larval-damaged leaves with prior egg deposition compared to damaged leaves that had never had eggs. There were also few significant changes in the transcript levels of glucosinolate metabolic genes, except that egg deposition suppressed the feeding-induced up-regulation of FMOGS-OX2, a gene encoding a flavin monooxygenase involved in the last step of 4-methylsulfinylbutyl glucosinolate biosynthesis. Hence, our study demonstrates that oviposition does increase A. thaliana resistance to feeding by subsequently hatching larvae, but this cannot be attributed simply to changes in glucosinolate content.

Insect Egg Deposition Induces Indirect Defense and Epicuticular Wax Changes in Arabidopsis thaliana

Egg deposition by the Large Cabbage White butterfly Pieris brassicae on Brussels sprouts plants induces indirect defense by changing the leaf surface, which arrests the egg parasitoid Trichogramma brassicae. Previous studies revealed that this indirect defense response is elicited by benzyl cyanide (BC), which is present in the female accessory reproductive gland (ARG) secretion and is released to the leaf during egg deposition. Here, we aimed (1) to elucidate whether P. brassicae eggs induce parasitoid-arresting leaf surface changes in another Brassicacean plant, i.e., Arabidopsis thaliana, and, if so, (2) to chemically characterize the egg-induced leaf surface changes. Egg deposition by P. brassicae on A. thaliana leaves had similar effects to egg deposition on Brussels sprouts with respect to the following: (a) Egg deposition induced leaf surface changes that arrested T. brassicae egg parasitoids. (b) Application of ARG secretion of mated female butterflies or of BC to leaves had the same inductive effects as egg deposition. Based on these results, we conducted GC-MS analysis of leaf surface compounds from egg- or ARG-induced A. thaliana leaves. We found significant quantitative differences in epicuticular waxes compared to control leaves. A discriminant analysis separated surface extracts of egg-laden, ARG-treated, untreated control and Ringer solution-treated control leaves according to their quantitative chemical composition. Quantities of the fatty acid tetratriacontanoic acid (C34) were significantly higher in extracts of leaf surfaces arresting the parasitoids (egg-laden or ARG-treated) than in respective controls. In contrast, the level of tetracosanoic acid (C24) was lower in extracts of egg-laden leaves compared to controls. Our study shows that insect egg deposition on a plant can significantly affect the quantitative leaf epicuticular wax composition. The ecological relevance of this finding is discussed with respect to its impact on the behavior of egg parasitoids.

Root and shoot jasmonic acid induction differently affects the foraging behavior of Cotesia glomerata under semi-field conditions

Plants can accumulate and release defensive chemicals by activating various signaling pathways when they are damaged by herbivores or pathogens. The jasmonic acid pathway is activated after damage by chewing herbivores. Here we used jasmonic acid (JA) as an exogenous elicitor to induce feral cabbage plants. In this study, the effects of root JA (RJA) and shoot JA (SJA) induction on the foraging behavior of Cotesia glomerata, a parasitoid of the large cabbage white butterfly Pieris brassicae, was investigated under semi-field conditions. In all combinations of differently induced plants (RJA, SJA and control plants), the percentages of shoot induced plants that were visited by at least one wasp were significantly higher than those of controls or root induced plants during 3 h of foraging. Consequently, parasitism rates of P. brassicae on shoot-JA induced plants were significantly higher than on plants induced with JA to the roots or control plants in all tests. However, this behavioral preference was not reflected in the allocation of offspring. The clutch sizes of C. glomerata eggs on control, root induced and shoot induced plants were not significantly different from each other in two-choice or three-choice experiments, but did differ with clutch size in the two-choice experiment of uninduced control plants versus SJA. This semi-field study helps to further understand the choice behavior and preferences of parasitoids in natural multitrophic communities in which plants induced with root or shoot herbivores occur together.

The Biosynthesis of Hexahydrofarnesylacetone in the Butterfly Pieris brassicae

Hexahydrofarnesylacetone (6,10,14-trimethylpentadecan-2-one, 1) is a widespread ketone occurring in plants and insects. Several species use this compound or the respective alcohol as part of their pheromone bouquet. Here, we showed by using deuterium labeled phytol (3) and GC-MS experiments that the Large Cabbage White butterfly Pieris brassicae can take up phytol in the larval stage and transforms it into 1 by oxidative degradation.

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.

Do parasitized caterpillars protect their parasitoids from hyperparasitoids? A test of the ‘usurpation hypothesis’

Caterpillars that are attacked by some species of parasitoid wasps are known to survive for several days after the parasitoid larvae emerge and pupate. It has been argued that the behaviour of the parasitized larva is ‘usurped’ by the parasitoid and that it ‘guards’ the parasitoid cocoons against their own natural enemies such as hyperparasitoids (the ‘usurpation hypothesis'). We tested this hypothesis in the association involving a gregarious endoparasitoid, the wasp Cotesia glomerata; caterpillars of its host, the large cabbage white butterfly Pieris brassicae; and a pupal hyperparasitoid, the wasp Lysibia nana. In laboratory experiments, we presented cocoon broods of C. glomerata to single females of L. nana in arenas for 6 h. We tested several treatments for rates of primary parasitoid survival, including variation in the position of the caterpillar and the presence or absence of an additional silk web spun by parasitized caterpillars. Parasitized P. brassicae larvae survived longer than the period necessary for C. glomerata adults to emerge. Rates of parasitoid survival were, however, unaffected by the presence of a P. brassicae larva on the cocoon brood, although significantly more parasitoids emerged when the silk web was present. Analyses of the foraging behaviour of individual L. nana females in arenas, performed using Observer software, revealed that the wasps showed a greater tendency to leave cocoons when caterpillars and silk were present. The laboratory experiments only partially support the usurpation hypothesis. In nature, usurpation of the host of the primary parasitoid may be a more effective strategy against generalist predators than against more specialized and better-adapted hyperparasitoids.

Associative learning of visual and gustatory cues in the large cabbage white butterfly, Pieris brassicae

AbstractThe landing response of the large cabbage white butterfly Pieris brassicae was studied under controlled optical and gustatory stimulus conditions. Experience-based changes in landing behaviour were examined by offering cardboard circles of two different shades of green, treated with either an oviposition stimulant or a deterrent. We employed two training situations. In one situation the two shades of green, carrying either the stimulant or the deterrent, were offered simultaneously, in the other sequentially. During the 1 hour training periods, butterflies were either landing and drumming spontaneously or they were caught at the end of the period and placed on the artificial leaves until tarsal drumming ensued. Our experiments demonstrated that P. brassicae females can learn to associate visually detected substrate characteristics with contact-chemosensory information available only after landing. Furthermore, a learned preference for a substrate could be turned into a preference for the alternative substrate by exposing the insect to a deterrent on the previously preferred substrate. These results provide indications of aversion learning, thus far undocumented in oviposition behaviour of Lepidoptera. Bringing the butterflies into forced contact with the oviposition stimulant resulted in similar effects on landing preference compared to those of spontaneous landing, but spontaneous landing had a stronger effect on preference for associations involving the deterrent. The simultaneous training regime, which supposedly requires a less important role for short-term memory, was more effective in modifying landing preferences.