Population dynamics of Lucilia eximia (Dipt., Calliphoridae)

Abstract:  The theoretical dynamics of experimental populations of Lucilia eximia was investigated as an attempt to understand its population biology. Specifically the population dynamics of L. eximia was analysed by means of a mathematical model that incorporates fecundity and survival as density-dependent demographic parameters in discrete time. The sensitivity of these parameters to changes in the magnitude was also investigated. The mathematical model applied to experimental populations of L. eximia predicts a theoretical one-point equilibrium for immatures. The population dynamics of L. eximia is compared to the dynamics of Chrysomya species and Cochliomyia macellaria.     

Seasonal population dynamics in Lucilia eximia (Wiedemann) (Diptera: Calliphoridae)

In this study the seasonal variation of fecundity, wing and tibia sizes were investigated in natural populations of Lucilia eximia (Wiedemann) as an attempt to determine the variations in life history of the species associated to seasonality. Specimens of L. eximia were monthly collected in Botucatu, S?o Paulo, Brazil, during two years and the adult females dissected to estimate fecundity. Body size was estimated by measuring wing and tibia. Fecundity and body size were seasonally analysed. A relatively constant temporal trajectory was found for fecundity, wing and tibia size over twenty-four months. Strong positive correlations between wing and tibia size, fecundity and wing and fecundity and tibia were observed. The maintenance of stable values in L. eximia indicates that it has suffered little seasonal influence over the period analysed. This result confirms the demographics and life history stable profile of the species in spite of seasonal climatic changes observed in the study area.     

Host shifting by Operophtera brumata into novel environments leads to population differentiation in life-history traits

Abstract.  1. Operophtera brumata L. (Lepidoptera: Geometridae), a polyphagous herbivore usually associated with deciduous trees such as oak Quercus robur L . , has expanded its host range to include the evergreen species heather Calluna vulgaris (L.) Hull and, most recently, Sitka spruce Picea sitchensis (Bong.) Carrière.
2. Phenology, morphology, and survival of O. brumata were measured at several life-history stages in populations from the three different host plant communities sampled from a range of geographical locations. The data were used to test for population differences, reflecting the marked differences in host-plant secondary chemistry, growth form, and site factors such as climate. The hypothesis that spruce-feeding populations originated from populations feeding on moorland, commonly sites of coniferous afforestation, was also tested.
3. Altitude, not host plant species, was the major influence on the timing of adult emergence. An effect of insect population independent of altitude was found, implying that additional unidentified factors contribute to this phenological variation. Larval survival and adult size varied between populations reared on different host plant species. Survival of larvae was affected negatively when reared on the novel host plant, Sitka spruce, versus the natal plant (oak or heather) but oak and heather-sourced insects did not differ in survivorship on Sitka spruce.
4. Host range extension into novel environments has resulted in population differentiation to the local climate, demonstrating that host shifts pose challenges to the herbivore population greater than those offered by the host plant alone. The hypothesis that Sitka spruce feeding populations have arisen predominantly from moorland feeding populations was not supported.     

Molecular evidence using enzyme and RAPD markers for sympatric evolution in British species of Tetramesa (Hymenoptera: Eurytomidae)

Some species of the insect genus Tetramesa (Hymenoptera: Eurytomidae), which has a world‐wide distribution, are morphologically very similar, both in the adult and larval stages. In the British Isles, there are 37 recorded species, all of which feed on grasses as larvae and are largely host specific. Some form galls on their hosts; others do not. We used a range of enzyme and random amplified polymorphic DNA (RAPD) markers to investigate a complex of five cryptic species occurring sympatrically in the UK, collected from seven sites in mainland England and Wales: T. calamagrostidis (von Schlechtendal), T. longicornis (Walker) and T. petiolata (Walker) infesting different grass hosts, and T. hyalipennis (Walker) s.l. comprising two‐host adapted forms (labelled 1 and 2) reared from the grasses Elymus repens and E. farctus, respectively. Nine soluble enzyme systems (some known to be polymorphic in other insects) and 37 RAPD primers allowed taxonomic separation of the species. However, whilst RAPD markers were able to discriminate between the two host‐adapted forms of T. hyalipennis, enzyme markers (producing phenotypic profiles in the absence of genetic crosses) could not. Upon calculating genetic distances for the RAPD data from which a cladogram of Euclidean distances (relatedness) was produced along with multivariate analysis of the data, T. longicornis was shown to be the most ‘basal’ species, and most related to T. hyalipennis s.l.; T. calamagrostidis and T. petiolata were found to be more distantly related to these species but most closely related to each other. The two forms of T. hyalipennis s.l. appear to be the most closely related of any of the species investigated, probably diverging the most recently. From this data, and since the populations examined were all sympatric without obvious physical barriers to reproduction, it can be concluded that some degree of sympatric evolution has occurred, most obviously in the case of the host‐adapted forms of T. hyalipennis. If so, this complex of species could be another rare example of sympatric speciation in insects. Further research using more sophisticated molecular markers such as microsatellites, amplified fragment length polymorphic markers (AFLPs) and DNA sequencing (e.g. of mtDNA and ribosomal DNA regions), in conjunction with behavioural studies, are required to further elucidate this interesting species group. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 83 , 509–525.     

Genetic diversity of natural populations of Arabidopsis thaliana (L.) Heynh. in Karelia

The genetic structure of ten natural populations of Arabidopsis thaliana (L.) Heynh. at eight isozyme loci was studied. The populations were located in the northern part of the species range, 200 km from the north to the south along the Onega Lake coast in Karelia. Considerable genetic diversity (P99% = 43.7, Hobs = 0.003) was revealed that is not typical of populations of self-pollinating plant species. A direct correlation between the proportion of polymorphic loci and geographical latitude was shown (r = 0.68; P < 0.05). It is suggested that a high polymorphism level in Karelian Arabidopsis thaliana (L.) populations increasing from the south to the north is due to extreme environmental conditions in the northern part of the species range. The distribution of genetic diversity within and between populations is typical of self-pollinating species: the larger part of the total diversity resides among populations (GST = 0.583).     

Interactions between the phloem-feeding speciesTomicus piniperda (Col.: Scolytidae) andAcanthocinus aedilis (Col.: Cerambycidae), and the predatorThanasimus formicarius (Col.: Cleridae) with special reference to brood production

Interactions betweenTomicus piniperda (L.) (Col.: Scolytidae),Acanthocinus aedilis (L.) (Col.: Cerambycidae) andThanasimus formicarius (L.) (Col.: Cleridae) were investigated in caged pine bolts. The treatments wereT. piniperda alone,A. aedilis alone,T. piniperda together withA. aedilis, T. piniperda together withT. formicarius and all three species together. T. piniperda offspring production per m² was reduced by 92% when reared withT. formicarius, by 78% when reared withA. aedilis, and by 94% when all three species were reared together, compared withT. piniperda reared alone.A. aedilis had a negative influence on the offspring production ofT. formicarius and vice versa. When both species were present in the same bolt (together withT. piniperda) offspring production was reduced by 74% forA. aedilis and by 42% forT. formicarius compared with their respective production values when each species was present alone with the bark beetle. The new generation ofT. formicarius emerged as larvae from June to August while most of theA. aedilis offspring emerged as adults from September to October, leaving only a few larvae in the bolts to hibernate.A. aedilis only reproduced in a small part of one of the bolts without bark beetles.     

Parasitic hymenoptera fauna on agromyzidae (diptera) colonizing weeds in ecological compensation areas in northern Italian agroecosystems

Parasitoids (Hymenoptera) associated with agromyzid leafminers (Diptera: Agromyzidae) were studied in three rural farms located in northern Italy. The parasitoids were reared from mined foliage of weeds growing in field margins. We reared 998 Hymenoptera specimens, representing five families, 23 genera, and 53 species, from leafminers infesting weeds. Eulophidae was the most abundant family (67.64%), followed by Braconidae (28.86%), Eucoilinae (1.40%), Tetracampidae (1.40%), and Pteromalidae (0.7%). Braconids was the most species rich family, accounting for 28 species; eulophids were represented by 19 species, pteromalids by four species, and eucoilins and tetracampids by one species each. The dominant parasitoid was the eulophid Pediobius metallicus (Nees), representing 18.17% of the total, followed by Diglyphus isaea (Walker) (12.73%), and Neochrysocharis formosa (Westwood) (10.82%). The most abundant braconid parasitoid was Dacnusa maculipes Thomson (9.62%). More than 80% of parasitoids were recovered from 10 plant species: Cirsium arvense (L.) Scopoli, Plantago lanceolata L., Sonchus asper (L.) Hill, Papaver rhoeas L., Picris echioides L., Lactuca serriola L., Myagrum perfoliatum L., Ranunculus velutinus Tenore, Arctium lappa L., and Medicago sativa L. The retention and the management of wild plants within field margins can be crucial tools to enhance the populations of biological control agents of agromyzids and to conserve rare parasitic wasp species.     

Light brown apple moth in California: a diversity of host plants and indigenous parasitoids

The light brown apple moth, Epiphyas postvittana (Walker), an Australia native tortricid, was found in California in 2006. A field survey of host plants used by E. postvittana was conducted in an urban region of the San Francisco Bay Area. An inspection of 152 plant species (66 families), within a 23-ha residential community, found E. postvittana on 75 species (36 families). Most (69 species) host plants were not Australian natives, but had a wide geographic origin; 34 species were new host records for E. postvittana. Heavily infested species were the ornamental shrubs Myrtus communis L., Pittosporum tobira (Thunb.) W.T. Aiton, Euonymus japonicus Thunb., and Sollya heterophylla Lindl. To survey for parasitoids, four urban locations were sampled, with E. postvittana collected from five commonly infested plants [M. communis, P. tobira, E. japonicus, Rosmarinus officinalis L., and Genista monspessulana (L.) L.A.S. Johnson]. Twelve primary parasitoid species and two hyperparasitoids were reared; the most common were the egg parasitoid Trichogramma fasciatum (Perkins), the larval parasitoids Meteorus ictericus Nees, and Enytus eureka (Ashmead), and the pupal parasitoid Pediobius ni Peck. Meteorus ictericus accounted for >80% of the larval parasitoids, and was recovered from larvae collected on 39 plant species. Across all samples, mean parasitism was 84.4% for eggs, 43.6% for larvae, and 57.5% for pupae. The results are discussed with respect to the potential for resident parasitoid species to suppress E. postvittana populations.     

Impact of Gyranusoidea tebygi Noyes (Hymenoptera: Encyrtidae) on the Mango Mealybug Rastrococcus invadens Williams (Homoptera: Pseudococcidae) in Nigeria

This study investigated the impact of released exotic mango mealybug parasitoid Gyranusoidea tebygi on mango mealybug Rastrococcus invadens in Nigeria. Observations were also made on the occurrence of the mealybug on other host plants in the surveyed areas. The monitoring exercise started in 1991 about 2 years after the first release in Ibadan. By 1997 and 1998, G. tebygi was found to have crossed all agro-ecological barriers to colonize the entire area of infestation nationwide on mango as well as other host plants. During this period, the populations of R. invadens had greatly decreased from between 11.0 and 98.0 mealybugs per leaf in 1991 to between 0.0 and 18.2 mealybugs per leaf in 1998. This fall was attributed to the activities of the released parasitoid. At many sampling sites in 1998, mealybugs were virtually absent on both mango and other host plants. Predators that were observed during the survey, were the coccinellids: Exochomus promptus Weise, Chilocorus nigritus (F) and Nephus spp. Larvae of chrysopid species, Ceratochrysa autica (Walker) and Plesiochrysa sp. The hyperparasitoids reared from mummies were Marietta leopardina Motsch (Aphelinidae), Chartocerus hyalipennis Hayat and Chartocerus subaeneus (Forster) (Signiphoridea).     

Subsociality in halictine bees

To look for the occurrence and the significance of brood care in social evolution, I reared six eusocial halictine bee species in laboratory cages enabling the observation of intranest behaviour: Lasioglossum (Evylaeus) laticeps, L. (E.) pauxillum, L. (E.) nigripes, L. (E.) euboeensis, Halictus (Halictus) scabiosae and L. (E.) fulvicorne. All of them were subsocial, each mother caring for her brood. Brood cells were sealed after oviposition with earthen plugs; they were then reopened, visited and closed again. These observations plus the reports in the literature on eleven eusocial species indicate that seventeen species of eusocial halictine bees provide parental care, i.e. are subsocial. Brood care, subsociality, is strongly associated with eusociality. To study reversal from eusociality to subsociality, I have reared the non-eusocial form of two species within which there are or have been eusocial forms: Halictus (H.) rubicundus and Lasioglossum (E.) fratellum. They are secondarily solitary, having lost worker brood. However, both species still show brood care. This suggests that in transitions to eusociality, brood care antedated eusociality. To further examine this issue I reared two truly solitary species that are not derived from eusocial ancestors: Lasioglossum (E.) villosulum and L. (L.) quadrinotatum. Unlike secondarily solitary species, females of both these species close their brood cells after oviposition and ignore their progeny thereafter. This association strongly suggests that the subsocial route with maternal brood care is the route to eusociality in halictine bees.     

The separation of two hymenopteran parasitoids, Tersilochus obscurator and Tersilochus microgaster (Ichneumonidae), of stem-mining pests of winter oilseed rape using DNA, morphometric and ecological data

Tersilochus obscurator Aubert and Tersilochus microgaster (Szépligeti) are larval endoparasitoids of economically-important stem-mining pests of winter oilseed rape (Brassica napus L.) in Europe. They are difficult to separate morphologically. Their hosts are Ceutorhynchus pallidactylus (Marsham) and Psylliodes chrysocephala Linnaeus, respectively. The parasitoids' taxonomic status, identification, host range and phenology were studied using genetic, morphometric and ecological data. The study used 527 female parasitoids from the UK and Germany, either field-collected in emergence traps or reared from field-collected host larvae. Two morphometric characters, the ovipositor sheath to first metasomal tergite ratio and the percentage of the mesopleuron spanned by the sternaulus, were measured. A 440 bp section of mitochondrial DNA cytochrome oxidase subunit I (COI) gene was sequenced from 35 parasitoids reared from C. pallidactylus, 20 reared from P. chrysocephala and individuals from two outgroups, Tersilochus heterocerus Thomson and Phradis interstitialis Thomson. Distinct and invariable COI sequences corresponded exclusively to each parasitoid group, confirming that T. obscurator and T. microgaster are discrete species. Measurements of host-reared and COI-sequenced specimens indicated that the ranges of both morphometric characters overlapped between species. Using these ranges as criteria, all but 3.6% of UK specimens and 2% of German specimens were identifiable to species without reference to host or phenology. There were differences in emergence phenology in the UK, adult T. microgaster emerging from winter diapause by 29 March 2000, T. obscurator emerging between 12 April and 24 May 2000. The value of molecular techniques in the identification of closely-related parasitoid species is discussed.     

A new species of Eriopeltis Signoret (Homoptera: Coccidae) from Britain

Abstract. Eriopeltis varleyi from Wytham in Britain is described as new. The adult female and male are described and all stages are illustrated. Keys are provided for the identification of all known species of Eriopeltis, and to the males of the three species known from Britain. E. varleyi is univoltine and apparently specific to Brachypodiumpinnatum (L.) Beauv. Males and females occur in equal proportions, but many more males were produced when populations were reared under very warm dry conditions in the laboratory. The population studied at Wytham was parasitized by a number of species of chalcid wasps and a chamaemyid fly egg predator.     

Host quality of different aphid species for rearing Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae)

This study aimed to evaluate the quality of the aphid Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) and Brevicoryne brassicae (L.) as hosts for the parasitoid Diaeretiella rapae (McIntosh). Parasitization by D. rapae was higher on M. persicae than on L. erysimi and B. brassicae. The time of development of D. rapae from egg to mummy or egg to adult male or female were shorter on M. persicae than on L. erysimi and B. brassicae. Moreover, D. rapae showed no significant differences in the emergence rate, sex ratio and longevity when reared on the three aphid species. Myzus persicae was the largest aphid host, with B. brassicae and L. erysimi being of intermediate and of small size, respectively. Diaeretiella rapae reared on M. persicae was larger than when reared on L. erysimi and B. brassicae, and females of D. rapae were significantly larger than males on M. persicae, but males of D. rapae were larger than females when reared on L. erysimi. No difference in size was detected between males and females in parasitoids reared on B. brassicae. Among the aphid species studied, M. persicae was found to be the most suitable to D. rapae.     

Genetic Diversity in Natural Populations of Arabidopsis thaliana (L.) Heynh. from Karelia

The genetic structure of ten natural populations of Arabidopsis thaliana (L.) Heynh. at eight isozyme loci was studied. The populations were located in the northern part of the species range, 200 km from the north to the south along the Onega Lake coast in Karelia. Considerable genetic diversity (P _99% = 43.7, H _obs = 0.003) was revealed that is not typical of populations of self-pollinating plant species. A direct correlation between the proportion of polymorphic loci and geographical latitude was shown (r = 0.68; P < 0.05). It is suggested that a high polymorphism level in Karelian Arabidopsis thaliana (L.) populations increasing from the south to the north is due to extreme environmental conditions in the northern part of the species range. The distribution of genetic diversity within and between populations is typical of self-pollinating species: the larger part of the total diversity resides among populations (G _ST = 0.583).     

Variation between laboratory populations in the performance of the parasitoid Encarsia formosa on two host species, Bemisia tabaci and Trialeurodes vaporariorum

We tested the hypothesis that populations of the parthenogenetic parasitic wasp Encarsia formosa Gahan (Hymenoptera: Aphelinidae) differed in their ability to use two different host species, Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae). Of the three wasp populations tested, two populations had been reared for many generations on B. tabaci and one population had been reared for many years on T. vaporariorum. Performance was measured by the number of whitefly nymphs that were successfully parasitized by individual wasps, and performance on either host was measured in separate experiments. There was variation between wasp populations in their performance on the host B. tabaci, with one wasp population reared for many years on this host performing considerably better than the other two populations. There were no significant differences between populations in their use of the preferred host, T. vaporariorum. The experiments were conducted in such a way that we could distinguish heritable differences between populations from environmentally-induced conditioning differences due to the immediate host from which an individual wasp enclosed. In either experiment there were no significant effects of conditioning, although there was a trend within each population for wasps conditioned on T. vaporariorum to have higher performance than those conditioned on B. tabaci. Thirdly, we conducted a selection experiment, initiated with wasps from a single population historically reared on T. vaporariorum, to measure the effect of laboratory rearing on different hosts for 17 generations. We did not see any difference in the performance of wasps on B. tabaci after this period of rearing on either of the two hosts. In summary, populations of E. formosa do differ in their relative performance on B. tabaci. The one population that was tested further did not show any response to selection by rearing, but the ability to respond to selection on performance may not be equal for all populations. The possibility that wasp populations have differential performance on particular hosts may affect the use of this species as a biological control agent.     

Prolonged development time of the bark beetle predator Thanasimus formicarius (Col.: Cleridae) in relation to its prey species Tomicus piniperda (L.) and Ips typographus (L.) (Col.: Scolytidae)

1 The generation time of the bark beetle predator Thanasimus formicarius (L.) (Col.: Cleridae) was found to be predominantly two years both in the field and in rearing experiments conducted with two of its main prey species, the pine shoot beetle Tomicus piniperda (L.) and the spruce bark beetle Ips typographus (L.) (Col.: Scolytidae). 2 Emergence of T. formicarius adults in the first summer was only observed in one of the two rearing experiments, and these individuals represented only 6% of that generation. 3 All individuals not emerging as adults in the first summer remained as larvae in their pupal chambers until the second summer. Pupae were found starting around mid-June, and adults (in pupal chambers) were found from late July through to the end of August. 4 Newly emerged adults had to feed in order to survive hibernation. 5 The existence of T. formicarius races, specialized on certain bark beetle species and with phenologies matching their hosts, could not be demonstrated. After hibernation there was no difference in feeding activity, timing of egg-laying or proportion of egg-laying females between the T. formicarius adults reared as larvae on T. piniperda (flight period in April) and those reared as larvae on I. typographus (main flight period generally starting in late May or early June) when exposed to a temperature and day-length typical of the early spring conditions prevailing during the flight period of T. piniperda. 6 T. formicarius was parasitized by Enclisis vindex (Tschek) (Hym.: Ichneumonidae) in the pupal chamber. 7 The importance of these findings for the population dynamics of bark beetles is discussed.     

Transferability and characterization of microsatellite markers in two Neotropical Ficus species

Microsatellite markers were transferred and characterized for two Neotropical fig tree species, Ficus citrifolia and Ficus eximia. Our study demonstrated that microsatellite markers developed from different subgenera of Ficus can be transferred to related species. In the present case, 12 of the 15 primer pairs tested (80%) were successfully transferred to both of the above species. Eleven loci were polymorphic when tested across 60 F. citrifolia and 60 F. eximia individuals. For F. citrifolia, there were 4 to 15 alleles per locus, whereas expected heterozygosities ranged from 0.31 to 0.91. In the case of F. eximia, this was 2 to 12 alleles per locus and expected heterozygosities from 0.42 to 0.87.     

Role of diet and experience in the development of feeding behaviour in largemouth bass, Micropterus salmoides

Two groups of largemouth bass, Micropterus salmoides , were reared in the laboratory. One group was reared on an artificial, passive diet (frozen brine shrimp) whereas the second was reared on a natural, active diet (cultured zooplankton). Observations on the development of feeding behaviour indicated that the motor patterns and duration (number of weeks in the behavioural repertoire) of the feeding acts did not differ between fry reared on the two diets. While feeding on their respective diets, natural-diet fry performed significantly more orientations and bites, the two major early feeding acts, than did the artificial-diet fry. When tested with live fish prey, fish reared on the natural diet performed fewer orientations and strikes and captured more prey per fry than did the artificial-diet fry. Natural-diet fry had a significantly better net efficiency (captures minus strikes minus orientations) than did artificial-diet fry. Diet, experience, and length (T.L.) of fry affected their predator efficiency significantly. We argue that providing hatchery-reared bass fry with an opportunity to prey on live forage fish once or twice before their release would enhance their survival and eventual recruitment into natural populations.     

Changes associated with laboratory rearing in antennal sensilla patterns of Triatoma infestans, Rhodnius prolixus, and Rhodnius pallescens (Hemiptera, Reduviidae, Triatominae)

We examined changes in the array of antennal sensilla of three species of Triatominae (Triatoma infestans, Rhodnius prolixus, and R. pallescens) following their establishment for different periods in laboratory culture. In each case, the laboratory colonies were compared with conspecific samples taken directly from the field, by quantitative analysis of the sensilla arrays on the three distal segments of the antenna in terms of the densities of three types of chemoreceptors (basiconics and thick and thin walled trichoids) and one type of mechanoreceptor (bristles). Sensilla densities were compared by ANOVA or non-parametric tests, and by multivariate discriminant analysis. Strains of the same species reared in different laboratories showed significant differences in their sensilla arrays, especially when compared to field-collected material from the same geographic origin. A Bolivian strain of T. infestans reared in the laboratory for 15 years and fed at monthly intervals, showed greatest differences from its conspecific wild forms, especially in terms of reductions in the number of chemoreceptors. By contrast, an Argentine strain of T. infestans reared for 25 years in the laboratory and fed weekly, showed a relative increase in the density of mechanoreceptors. A Colombian strain of R. prolixus reared for 20 years and fed weekly or fortnightly, showed only modest differences in the sensilla array when compared to its wild populations from the same area. However, a Colombian strain of R. pallescens reared for 12 years and fed fortnightly, did show highly significant reductions in one form of chemoreceptor compared to its conspecific wild populations. For all populations, multivariate analysis clearly discriminated between laboratory and field collected specimens, suggesting that artificial rearing can lead to modifications in the sensory array. This not only supports the idea of morphological plasticity in these species, but also suggests caution in the use of long-established laboratory material for experimental studies designed to extrapolate the natural behaviour and physiology of these species.     

Selection of Cassida spp. from southern Africa for the biological control of Chrysanthemoides monilifera in Australia

Four species of tortoise beetle (Chrysomelidae, Cassidinae) (Cassida spatiosa Spaeth and three undescribed Cassida species, labelled 1. 2 and 3) from South Africa, were assessed as potential biological control agents against Chrysanthemoides monilifera monilifera (L.) T. Norl. and C. m. rotundata (DC.) T. Norl. These southern African plants are important weeds of conservation areas in Australia. In South Africa, Cassida spatiosa was found feeding on C monilifera subcanescens (DC.) T. Norl., Cassida sp. 1 on Chrysanthemoides monilifera pisifera (L.) T. Norl. and C m. monilifera, Cassida sp. 2 on C m. pisifera and Chrysanthemoides incana (Burm.f.) T. Norl. and Cassida sp. 3 on C. m. rotundata. The life cycle of each species was completed in about three months on the leaves of the host. Cassida species 1, 2 and 3 were tested against eight species of plant and only fed and completed development on Chrysanthemoides species and the related species. Calendula officinalis L. Cassida species 1 and 3 showed no preference between Calendula officinalis and Chrysanthemoides species for oviposition. Cassida species 3 was selected for further assessment as a biological control agent based on match to the host subspecies and target climate in Australia.