A laboratory study was conducted to examine tritrophic effects on the suitability of the peach-potato aphid, Myzus persicae (Sulzer), and tobacco aphid, Myzus persicae nicotianae (Blackman & Eastop), as prey for the two spot ladybird, Adalia bipunctata (L.), when the aphids were reared on either sweet pepper or tobacco. Significant host plant-aphid interactions were evident for every component of development (juvenile survival, developmental time, adult mass at emergence) and reproduction (pre-oviposition period, fecundity, fertility). By almost all measures, the suitability of each aphid species was improved by rearing on its host plant of origin and diminished by rearing on the alternative host plant. The symmetry of the interactions are suggestive of both positive and negative host plant effects on aphid suitability as prey. Whereas M. p. nicotianae may be better able than M. persicae to detoxify the nicotine that is likely responsible for the reduced suitability of M. persicae when reared on tobacco, it appears to have lower nutritive value for A. bipunctata than M. persicae when reared on pepper. Thus, population parameters (R0, rm, l and DT) derived from performance data indicated that M. persicae reared on sweet pepper was the most suitable prey and that the same species reared on tobacco was the least suitable, with other host plant-aphid combinations intermediate., Mohammad A. Jalali, J.P. Michaud., and Obsahuje seznam literatury
Fifteen different mitochondrial haplotypes of the mtDNA gene COI encoding cytochrome C oxidase subunit I were identified in the 127 individuals of Adalia bipunctata studied. Two mitochondrial haplotypes, H9 and H10, differed greatly from the others. The mitochondrial polymorphism in A. bipunctata is ancient, though its age remains to be evaluated. It is shown that mitochondrial haplotypes H9 and H10 and others coexisted in the original population of A. bipunctata before it spread throughout Eurasia from Western Europe to the Baikal Area, and before the differentiation of the subspecies A. bipunctata fasciatopunctata, which differs from the European form in its elytral pattern. In order to evaluate the possible origin of the ancient mitochondrial haplotypes in the gene pool of A. bipunctata sequences of the mtDNA gene COI and of the rRNA second internal transcribed spacer of the four species of Adalia: A. bipunctata, A. decempunctata, A. frigida and A. tetraspilota, were compared. It is suggested that infection with Rickettsia had an important role in the preservation of the mitochondrial haplotypes H9 and H10 during the evolution of Adalia., Ilya Zakharov, Elena Shaikevich., and Obsahuje seznam literatury
Certain alkanes or their mixture present on the surface of ladybird elytra is important in the recognition of potential mates. Similar chemicals are present in the tracks of larvae, which deter conspecific female ladybirds from laying eggs in aphid colonies already being attacked by larvae. Finally, the shell of ladybird eggs is covered with alkanes that deter other species of ladybirds from eating the eggs. In each case the alkanes are similar although they fulfil different functions. There are, therefore, indications that ladybirds exploit their natural product with parsimonious versatility.
Cannibalism and intraguild predation (IGP) are both common phenomena amongst aphidophagous coccinellids and serve as vital alternative feeding strategies which can prolong survival during periods of aphid scarcity. A reduction in essential prey density and the acceptance of conspecific or heterospecific prey are likely to have a considerable influence on both larval development and adult reproduction. However, little is known about the legacy of larval diet on adult performance. This paper considers the effects of the diet provided to larvae of Harmonia axyridis (Pallas) and Adalia bipunctata (Linnaeus) (Coleoptera: Coccinellidae) on the reproductive output of the resulting females. Results showed that larval diets, including treatments analogous to competition and IGP, did not affect adult longevity, ovipositional lag, proportion of eggs laid in clutches or ovariole number in H. axyridis or A. bipunctata. However, some variation in the maximum clutch size and oviposition rate was seen. A larval diet of unlimited aphids resulted in the largest clutches of eggs being laid by both species. The total number of eggs laid over 30 days was largest for H. axyridis when larvae were reared on unlimited aphids or limited aphids supplemented with either conspecific or heterospecific eggs, whereas oviposition was lower for A. bipunctata females that had received conspecific or heterospecific eggs in their larval diets. The results have also enabled us to make some general comparisons of reproductive parameters between the two species, and to refute the hypothesis that the maximum clutch size laid by a female ladybird is limited by the number of ovarioles within an ovary. We conclude that IGP of A. bipunctata eggs by H. axyridis larvae has a positive effect on reproductive output and is therefore likely to further contribute to the spread and increase of H. axyridis in Britain.
One factor limiting the adoption of aphidophagous coccinellids in augmentative biological control is cost-effective mass production. The use of factitious foods may lower production costs by reducing space and manpower requirements for mass rearing of the predator and its prey and by enhancing mechanization of rearing procedures. The objective of this study was to compare the efficiency of food conversion, consumption indices and growth rates of first to fourth instars of Adalia bipunctata when fed either a mixture of Ephestia kuehniella eggs and fresh bee pollen, or on the natural prey Myzus persicae. Larval survival did not differ among treatments, averaging 80 and 90% on the respective diets. Mean dry body weights of the coccinellid were significantly lower on M. persicae than on the factitious food only for second instars and the pre-pupal stage. Dry food consumption by the predator throughout larval development averaged 20.61 mg on factitious food and 14.82 mg (corresponding to an average of 284 third and fourth instars) on M. persicae. The efficiency of conversion of ingested food for total larval development averaged 25 and 30% on factitious food and aphids, respectively. The relative growth rate of the larval instars was higher on aphids, whereas the consumption index was higher on the mixture of E. kuehniella eggs and pollen. An additional experiment showed that rearing the previous instars on the factitious food had no substantial effect on aphid consumption in the fourth instar. The study suggests that this factitious diet may be an appropriate food source for mass rearing A. bipunctata.
In the last two decades a huge amount of research has focused on the invasive harlequin ladybird, Harmonia axyridis, particularly on potential or actual deleterious effects that have arisen after it has colonised new regions. A focus of this work has been real or anticipated declines in native ladybird abundance since the introduction of H. axyridis, for which it is deemed responsible. Scientists have generally painted a very bleak picture of the effects of H. axyridis on native species: in this paper I argue that the picture painted is often too bleak. I use the case of the 2-spot ladybird, Adalia bipunctata, the species most often invoked as threatened by H. axyridis, to illustrate my point. While there is little question that H. axyridis has led to a decline in A. bipunctata populations in Europe, it seems likely that prior to the invasive ladybird's arrival A. bipunctata occurred in artificially high numbers in the urban environments in which it was typically studied. Pollution in towns and cities led to enhanced numbers of prey aphids on plants there which initially favoured A. bipunctata, and later H. axyridis. Thus one species, A. bipunctata, that has benefitted from an association with humans has been replaced by another, H. axyridis, just as brown rats replaced black rats in Europe and North America. Viewed with a longer perspective, A. bipunctata has more likely declined back to pre-industrial levels: the artificially high level from which it has declined recently was not a 'natural' one, and thus its decline from this level does not imply that it is now threatened or endangered. More broadly, we need a wider perspective, encompassing other ladybirds, longer timeframes and better comparisons with other (non-ladybird) invasive species to more clearly assess whether H. axyridis really poses as much of a threat as is often proposed., John J. Sloggett., and Obsahuje bibliografii
Adalia bipunctata is a well-known predaceous ladybird distributed in Europe, Central Asia and North America. This species has not been recorded in Japan. Recently, we found this species in the Osaka Bay area in central Japan, and assume that it was imported with goods such as timber by ships. We studied the life history and the distribution in the Osaka Bay area since the initial discovery. The larvae and adults preyed on aphids (mainly, Periphyllus viridis) on trees such as Acer buergerianum and Rhaphiolepis umbellata. The over-wintered adults appeared in March and laid eggs. The adults emerged in spring, and were in the rolled leaves throughout the rest of the year. Thus, in Japan this ladybird is univoltine with long inactivity in adult. The life history of Japanese population of A. bipunctata differs considerably from other areas where populations are multivoltine. The developmental threshold was estimated to be 6.3°C and the sum of effective temperatures was 322.6 day-degrees for the period from egg to adult emergence. Predation on prepupae of A. bipunctata by the larvae of native species such as Harmonia axyridis was observed occasionally.
Coccinella septempunctata was approximately 20% more reluctant to eat the eggs of Adalia bipunctata than the reverse. In addition, fourth instar larvae of C. septempunctata failed to complete their development on a diet of A. bipunctata eggs and only 30% of those of A. bipunctata completed their development on a diet of C. septempunctata eggs, and the survivors took nearly 2 times as long as those fed aphids. This is an indication that the costs of intraguild predation might outweigh the benefits.
Winglessness in the two-spot ladybird beetle Adalia bipunctata (L.) is determined by a single locus with the wingless allele recessive to the winged wildtype allele. The expression of the wingless trait is highly variable, with individuals missing a variable part of elytra and flight wings; the elytra and wings appear to be truncated rather than miniature in form. The degree of winglessness is partly determined genetically. Here we report on the phenotypic plasticity of the degree of winglessness. The environmental effect on elytron length relative to maximal elytron length in wingless phenotypes was studied by rearing offspring of single pair crosses of this form at a low (19°C) or high (29°C) temperature. Offspring reared at 19°C showed relatively longer elytra than those reared at 29°C.
Although there are few studies of the sexual life of coccinellids these phenomena have attracted the interest of isolated groups of coccinellidologists. Probably the most important finding is that at least some coccinellid species (Adalia bipunctata and Harmonia axyridis) do not mate at random with the females prefering certain males. This phenomenon was first observed in Adalia bipunctata by Lusis and then studied in detail by Majerus, O'Donald, de Jong and others. In Japan, Harmonia axyridis was similarly studied by Osawa and Ueno. While the former author found that in this species (as in A. bipunctata) the colour of the elytra is most important in mate choice by females, the latter stresses that size and activity are important. Sperm competition is another interesting phenomenon, most often the sperm of the last male fertilizes the eggs (Ueno, Katakura). Obata and Hidaka have contributed in an important way to elucidating the function of the spermatophore in mating. The studies by Hodek and Ceryngier recorded the maturation and regression of testicular follicles and the relation of mating activity to diapause in four coccinellid species. In contrast to females, where induction of diapause prevents maturation of ovaries, in diapausing males the tissue of testicular follicles remains active until the temperatures decrease in late autumn. Dissection of spermathecae revealed principal difference in autumn mating activity between Coccinella septempunctata, in which 40-60% of the beetles mated before hibernation and Ceratomegilla (syn. Semiadalia) undecimnotata, which does not mate in autumn.