Adult-obtained pyrrolizidine alkaloids defend ithomiine butterflies against a spider predator

Brown, Keith S.

doi:10.1038/309707a0

Cited by 210 publications

(116 citation statements)

References 16 publications

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“…The finding that Utetheisa benefits from the possession of alkaloid vis-à-vis an egg predator that might otherwise inflict a heavy toll on the eggs underscores what was apparent already from earlier studies, namely that such alkaloids, which presumably evolved as defensive agents in plants, can serve for protection also in insects that secondarily incorporate the chemicals (1,(18)(19)(20)(21)(22)(23). C. cubana is not the only Utetheisa egg predator deterred by the alkaloids.…”

Section: Discussionmentioning

confidence: 69%

Chemical defense against predation in an insect egg

Eisner

Eisner²,

Rossini³

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

113

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The larva of the green lacewing (Ceraeochrysa cubana) (Neuroptera, Chrysopidae) is a natural predator of eggs of Utetheisa ornatrix (Lepidoptera, Arctiidae), a moth that sequesters pyrrolizidine alkaloids from its larval foodplant (Fabaceae, Crotalaria spp.). Utetheisa eggs are ordinarily endowed with the alkaloid. Alkaloidfree Utetheisa eggs, produced experimentally, are pierced by the larva with its sharp tubular jaws and sucked out. Alkaloid-laden eggs, in contrast, are rejected. When attacking an Utetheisa egg cluster (numbering on average 20 eggs), the larva subjects it to an inspection process. It prods and͞or pierces a small number of eggs (on average two to three) and, if these contain alkaloid, it passes ''negative judgement'' on the remainder of the cluster and turns away. Such generalization on the part of the larva makes sense, because the eggs within clusters differ little in alkaloid content. There is, however, considerable between-cluster variation in egg alkaloid content, so clusters in nature can be expected to range widely in palatability. To check each cluster for acceptability must therefore be adaptive for the larva, just as it must be adaptive for Utetheisa to lay its eggs in large clusters and to apportion alkaloid evenly among eggs of a cluster.Ceraeochrysa cubana ͉ Chrysopidae ͉ Utetheisa ornatrix ͉ Arctiidae ͉ pyrrolizidine alkaloid T he moth Utetheisa ornatrix (family Arctiidae) (henceforth called Utetheisa) endows its eggs with pyrrolizidine alkaloids [henceforth called alkaloid(s)]. It sequesters the chemicals as a larva from its foodplants, legumes of the genus Crotalaria (family Fabaceae), and retains them through metamorphosis into the adult stage. Both parents contribute to the egg endowment. The male transmits alkaloid to the female with the sperm package at mating, and the female allocates a portion of this gift, together with a share of her own alkaloid, to the eggs (1).Here we present evidence that the alkaloids protect the eggs against a natural enemy, the larva of the green lacewing, Ceraeochrysa cubana (family Chrysopidae) ( Fig. 1 A and B). Specifically, we demonstrate that (i) the larva, in laboratory tests, rejects alkaloid-containing Utetheisa eggs, while avidly consuming alkaloid-free eggs offered as controls; (ii) the larva exercises this discrimination in the field as well; (iii) the larva is more strongly deterred by the N-oxide form of the alkaloid than the free base form; (iv) the alkaloid in Utetheisa eggs occurs mainly in the N-oxide form; (v) the eggs in a given cluster are equally endowed with alkaloid; and (vi) the larva seems to act on this information: it abandons a cluster, no matter what the cluster size, if the first few eggs it samples are distasteful. Materials and MethodsThis study was done at our Cornell laboratories and at the Archbold Biological Station, Lake Placid, Highlands County, FL.Experimental Animals. Utetheisa occur at the Archbold Station, often in abundance, in association with stands of Crotalaria mucronata, the major local foodplant. ...

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Section: Discussionmentioning

confidence: 69%

Chemical defense against predation in an insect egg

Eisner

Eisner²,

Rossini³

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

113

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“…In that same species we have now demonstrated that the male passes much of his ingested alkaloid to the reproductive system for eventual copulatory transfer to the female and that The female in turn transmits the alkaloid to eggs (19). In ithomine butterflies, a group closely related to danaines, the alkaloid in eggs appears also to be of paternal origin (22,23). In such cases, where the female herself may contribute little or no alkaloid to the eggs, one would presume her to be particularly discriminating in courtship.…”

Section: Discussionmentioning

confidence: 99%

“…Sci. USA 85 (1988) (in at least some cases) themselves contain such alkaloids (19,(21)(22)(23)(24)(25). Males in some of these species also derive courtship pheromones from the ingested alkaloid (25,26).…”

Section: Discussionmentioning

confidence: 99%

Biparental defensive endowment of eggs with acquired plant alkaloid in the moth Utetheisa ornatrix.

Dussourd

Ubik

Harvis

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

208

133

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The eggs of Utetheisa ornatrix contain pyrrolizidine alkaloids. These compounds are contributed by both parents, who sequester them as larvae from their food plants.Females receive alkaloid from the males at mating, apparently by seminal infusion, and transmit this alkaloid together with alkaloid of their own to the eggs. Field and laboratory tests showed that the alkaloids protect eggs from predators. The alkaloidal contribution of the male, although smaller than that of the female, itself provides significant egg protection. A previously identified pheromone, derived by the male from the alkaloid and emitted during precopulatory behavior, may announce the male alkaloidal worth to the female.

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“…The polymorphism is unique among the 157 species of the subfamily Danainae (Ackery and Vane-Wright, 1984); it is, moreover, a surprising feature in an aposematic species that is chemically defended (Rothschild et al, 1975;Brower et al, 1975Brower et al, , 1978Brown, 1984; JA Edgar in litt. to DASS) and supports numerous mimics (Smith, 1973a(Smith, , 1976(Smith, , 1979Owen and Smith, 1993;Owen et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Incomplete sexual isolation in sympatry between subspecies of the butterfly Danaus chrysippus (L.) and the creation of a hybrid zone

et al. 2003

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Subspecies chrysippus, dorippus and alcippus of the butterfly Danaus chrysippus differ at three biallelic colour gene loci. They have partially vicariant distributions, but their ranges overlap over a substantial part of central and East Africa, where hybridism is commonplace. We now report that the West African subspecies alcippus differs from other subspecies, not only in nuclear genotype but also in mitochondrial haplotype in both allopatry and sympatry. The maintenance of concordant nuclear and cytoplasmic genetic differences in sympatry, and in the face of hybridisation, is prima facie evidence for sexual isolation. Other evidence that suggests alcippus may be isolated from chrysippus and dorippus include differences in sex ratio (SR), heterozygote deficiency at one site and deduced differences in patterns of migration. We suggest that, within the hybrid zone, differential infection of subspecies by a male-killing Spiroplasma bacterium causes SR differences that restrict female choice, triggering rounds of heterotypic mating and consequent heterozygote excess that is largely confined to females. The absence of these phenomena from hybrid populations that test negative for Spiroplasma supports the hypothesis. The incomplete sexual isolation and partial vicariance of alcippus suggests that it is a nascent species.

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Adult-obtained pyrrolizidine alkaloids defend ithomiine butterflies against a spider predator

Cited by 210 publications

References 16 publications

Chemical defense against predation in an insect egg

Chemical defense against predation in an insect egg

Biparental defensive endowment of eggs with acquired plant alkaloid in the moth Utetheisa ornatrix.

Incomplete sexual isolation in sympatry between subspecies of the butterfly Danaus chrysippus (L.) and the creation of a hybrid zone

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