Tyria Jacobaeae Research Articles

Natural Mortality of Cinnabar Moth1 in California

The cinnabar moth, Tyria jacobaeae (L.) (Lepidoptera: Arctiidae), an insect introduced for the biological control of tansy ragwort, Senecio jacobaea L., suffered considerable mortality at some study sites from 1967 through 1970. At the original site of colonization, one mile south of Fort Bragg, Calif., mortality was probably in excess of 85% in 1970. Factors influencing the mortality included predation by insects, sowbugs (Crustacea: Isopoda), and rodents, a microsporidian disease caused by Nosema sp., and some limited parasitism. Despite this relatively high mortality for an introduced insect, the cinnabar moth is well established in California, Oregon, and Washington. Populations have generally increased, and partial control of the pest plant is being obtained in some areas.

Experiments On Dispersal, Late-Larval Predation, and Pupation in the Cinnabar Moth (Tyria Jacobaeae L.) With a Radioactive Label (192Ir)

A number of experiments is described from which it is concluded that a predating ant, Lasius alienus Forst, locally has a very important influence on the population dynamics of the Cinnabar Moth. Moreover, Tyria appears to be absent in some of the dry dune vegetations and it is suggested that this is due to the presence of Lasius in high densities in those areas. The distribution pattern of pupae in the field could be explained by preference for certain pupation sites. The applied technique of labelling, with an external radioactive mark, proved satisfactory.

The population ecology of the Cinnabar Moth, Tyria jacobaeae L. (Lepidoptera, Arctiidae).

This paper describes the results of a study of the factors determining the abundance and distribution of the Cinnabar Moth in Britain. The main part of the study was on a population of the moth at Weeting Heath in Norfolk. This is an area of sandy heath which is heavily overgrazed by rabbits. Here the moth fluctuates violently in number and periodically it completely defoliates its food plant (ragwort, Senecio jacobaea L.) over large areas. This happened in 1960, 1961, 1967, and 1968.Since 1966, the numbers of the moth have been studied in detail and Life Tables are presented for five years.Adult fecundity varies considerably between years. This is due mainly to fluctuations in adult size resulting from changes in larval density. By comparison adult mortality and dispersal have little effect on fecundity; although there is some evidence to suggest that dispersal is density dependent. Because the number of eggs laid in one generation depends on the size of the previous generation, fecundity tends to be acting as a delayed density dependent factor.Mortality is low during the egg stage, but is high amongst young larvae, due mainly to arthropod predation. As the caterpillars grow they become immune from this predation. They are distasteful to vertebrate predators.A larval parasite, Apanteles popularis, kills many of the fully grown larvae. The highest rates of parasitism have coincided with the lowest densities of the moth, however, so that over the five years it has acted as an inverse density dependent factor.In 1967, the population became so large that the ragwort was completely defoliated, and about 20% of the caterpillars died from starvation. In the following year the population was still large and the ragwort plants were small, owing to the effects of defoliation in the previous year. Food ran out early in the season and about 50% of the larvae starved. Because of the overriding effect of starvation, total larval mortality tends to be density dependent.Mortality is high at, or immediately after, pupation and this is thought to be due primarily to predation by moles (Talpa europaea). Pupal mortality does not appear to be density dependent.The upward growth of the population is limited by food supply. Starvation led to a population crash, so that in 1969 only 62 eggs/150 m2 were laid compared with 17110 and 16493 in the previous two years. The rate of recovery of the population after this crash was dependent upon the rapid recovery of the ragwort plants. Owing to the wet summer in 1968, plant numbers actually increased after defoliation, due to regeneration from root buds. This was in spite of the fact that no seed was produced in the area in either 1967 or 1968.The only factor which appears to buffer the population against extinction in years when food runs out early in the season, is the heterogeneity within the moth and ragwort populations. The earliest individuals manage to obtain sufficient food in those patches of ragwort which survive longest.Large fluctuations in number only occur in some localities. Other populations of the moth persist at low density and never eat out their food supply. Some data are presented from such a population at Monks Wood. This site is on a heavy clay soil, rabbit grazing is less marked than at Weeting, and ragwort occurs only at a low density. The lusher vegetation supports a very large population of arthropod predators and these take a higher percentage of the young caterpillars than was found at Weeting. Pupal survival is also low due probably to waterlogging of the soil. Pupae can withstand considerable desiccation, but excessive moisture soon leads to their death.The distribution of the moth in Britain and its use for the biological control of ragwort are discussed.

Poisonous Alkaloids in the Body Tissues of the Cinnabar Moth (Callimorpha jacobaeae L.)

Callimorpha jacobaeae L. (the cinnabar moth) has a brilliant red and blackish warning coloration (aposematic), and is a day-flying moth known to be unacceptable to a wide variety of vertebrate predators1–3. The larva, which feeds on groundsel (Senecio vulgaris L.) and ragwort (Senecio jacobaeae L.), has a black and yellow warning coloration and is rejected by many birds, mammals, reptiles and amphibians; it is, however, preyed upon by various arthropods4. When roughly handled the imago ejects or leaks out a pungent secretion mixed with yellow haemolymph from its prothoracic glands5. The adult moth contains a remarkably high level of histamine in its body tissues (700 µg/g)—a substance frequently associated with poison glands in invertebrates6–8.

The Cinnabar Moth, Tyria jacobaeae for Control of Tansy Ragwort1

The cinnabar moth. Tyria jacobaceae (L.), is making promising progress in the control of tansy ragwort, Senecio jacobaea near Fort Bragg, California. Although the insect is established in other areas of California and Oregon, the densities of populations have not yet reached the level required for control of the plant. In California, biological development of the insect is synchronized with the development of the plant, and parasites, predators, and disease have had little effect on the population at Fort Bragg.

An attempt to control ragwort in Australia with the cinnabar moth, Callimorpha jacobaeae (L.) (Arctiidae : Lepidoptera)

This paper describes research on the cinnabar moth, Callimorpha jacobaeae, introduced from England and Italy to Australia for the control of the poisonous weed, ragwort (Senecio jacobaea). Studies were conducted for six seasons in a high rainfall area of southern Gippsland, Vic., where the impact of ragwort infestation on dairy pastures was severe. Callimorpha has a univoltine life cycle with an obligatory pupal diapause during winter. The termination of this diapause in introduced stocks was successful to a limited extent only, and changes in its duration required for synchronization with the southern hemisphere seasons adversely affected the reproductive capacity of emerging females. The larval progeny of Italian stock failed to survive in the field, and disappeared completely within the first season, whereas those of English origin were reasonably successful. In view of the low reproductive rate of Callimorpha and because of its numerous insect enemies, breeding was carried out in the field using techniques designed to provide protection from the locally abundant predators. An attempt was also made to assess factors playing a role in its numerical regulation. The larvae were liable to heavy mortality in the field due to the combined effect of fungal infections, insect predators, and parasites, and also to a virus disease introduced in a latent state with the insect. At an early stage of this work (the second Australian generation), a nuclear polyhedral virus epizootic destroyed 90% of the larval population. The fifth Australian generation was the last to survive in the field. Of the larval predators, the mecopteran Harpobittacus nigriceps caused the most serious mortality. This predator, common in all ragwort-infested areas of Victoria, showed a zonal pattern in its density distribution; the high density zones often overlapped sites occupied by larval colonies of the cinnabar moth. The larvae of Callimorpha were more frequently taken by Harpobittacus than tipulid flies (Macromastix spp.) which are normally its principal prey; the abundance and distribution of these flies was also studied. The abundance of both Harpobittacus and Macromastix, was influenced by weather factors, resulting in a marked annual fluctuation in their numbers. At times of high Harpobittacus abundance, mortality in larval colonies of Callimorpha due to this predator averaged over 80%, with extremes of 90-100% being observed frequently. The larvae of Callimorpha were found to be potentially efficient in controlling ragwort. The viable seed production of severely attacked plants was reduced, following defoliation and destruction of the primary flowerheads, by an average of over 98%. However, taking all factors into account, it is unlikely that Callimorpha could exert useful control of ragwort in Australia. There seems little chance that high larval densities, necessary to suppress seeding by ragwort, could be maintained in face of heavy predation. As the data presented in this paper indicate, Harpobittacus alone would be capable of preventing the effective establishment of C. jacobaeae in this country.

Establishment of the Cinnabar Moth, Tyria jacobaeae, on Tansy Ragwort in the Western United States2

The cinnabar moth, Tyria jacobaeae (L.), was first released in the United States for control of tansy ragwort, Senecio jacobaea L., in 1959 in northwestern California. Additional releases were made in 1960 in western Oregon and in western Washington and in 1961 and 1962 in California. Establishment resulted from most liberations of younger larvae, older larvae, or adults. The cinnabar moth now appears to be established in most of the areas where it has been released in Oregon and California, since significant numbers of next-generation larvae were found in these sites the year after their release. Releases in Washington apparently did not result in successful establishment.

Food-Plant Spectrum and Elimination of Disease of Cinnabar Moth Larvae, Hypocrita jacobaeae (L.) (Lepidoptera: Arctiidae)

The cinnabar moth, Hypocrita jacobaeae (L.), is the principal enemy of tansy ragwort, Senecio jacobaea L., in Europe. To determine if this moth could be safely liberated in Canada to control tansy ragwort, breeding stocks were imported as pupae from Sweden and Ireland for laboratory feeding tests. Larval feeding tests with various important economic plants before the moth was introduced to New Zealand from Britain (Cameron, 1935), to Australia from Britain (Currie and Fyfe, 1938), and to the United States from France (Parker, 1960) showed that the larvae would not survive on any of those tested. Such investigations specifically excluded certain crops from damage by the moth but did not indicate the range of plants that can be eaten. It is essential that an insect used in weed control should be highly restricted in its diet. If this restriction is related to nutrient discrimination, as described by Kennedy and Booth (1951) for Aphis fabae Scop., it would be necessary to screen many more economic plants than if it is related to “secondary” plant substances associated with a taxonomic group, as described by Fraenkel (1953). Thus, besides ad hoc tests on important plants, tests to determine the potential host spectrum of an insect are warranted before it is liberated against a weed. The plant spectrum of the cinnabar moth was determined by feeding the larvae on several genera in the tribe Senecioneae and representatives of most other tribes of Compositae that occur in Canada.

Termination of Pupal Diapause in the Cinnabar Moth and the Reproductive Capacity of the Resulting Females

MANY thousands of pupae of the cinnabar moth, Tyria jacobaeae L., from southern England, and a smaller consignment from central Italy, were introduced into Australia for the control of the noxious weed, ragwort (Senecio jacobaea L.), in southern Victoria. In England this moth has a strictly uni-voltine life-cycle1 that includes an obligatory pupal diapause2 lasting for an average of 270 days. Because of this diapause3, difficulties were expected in synchronizing emergence of the moths with the Australian summer—for this would require diapause to be terminated in less than 150 days or extended to at least 450 days.

Starvation Tests with Larvae of the Cinnabar Moth

Journal Article Starvation Tests with Larvae of the Cinnabar Moth Get access Harry L. Parker Harry L. Parker Entomology Research Division, Agr. Res. Serv. U.S.D.A. Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 53, Issue 3, 1 June 1960, Pages 472–473, https://doi.org/10.1093/jee/53.3.472 Published: 01 June 1960 Article history Accepted: 07 December 1959 Published: 01 June 1960

The Cinnabar Moth and Ragwort

The Cinnabar Moth and Ragwort