Glutathione S-transferase isoenzymes in the two-spot ladybird, Adalia bipunctata (Coleoptera: Coccinellidae)

Isoenzymes of glutathione S-transferase (GST) in adult Adalia bipunctata, an aphidophagous predator, were studied. Cytosolic GST activity was studied in each beetle developmental stage. The highest activities towards both 1-chloro-2,4-dinitrobenzene (CDNB) and 2,4-dinitro-1-iodobenzene (DNIB) occurred in adults. The enzyme distribution was investigated in adults. While most of the enzymatic activity was found in the abdomen (40-50 and 34-63% respectively) using several concentrations of both CDNB and DNIB, significant differences were observed for the head and the thorax depending on the substrate. Activities were more abundant in the thorax with DNIB (37-47%) compared to the 13-19% obtained with CDNB. Some GST activity was also detected in the elytra. GSTs were purified by epoxy-activated Sepharose 6B affinity chromatography and applied to an HPLC column to determine the native molecular weight (69 kDa). Three isoenzymes were separated by chromatofocusing at pH ranges 7-4. Three bands with molecular mass from 23 to 26 kDa were visualised on SDS-PAGE. Their isoelectric points were 6.66, 6.36, and 6.21. The substrate specificities and the kinetic parameters (Vm and Km) of the isoenzymes showed large differences depending on the isoenzyme. Arch.     

The effect of female mating history on sperm precedence in the two-spot ladybird, Adalia bipunctata (Coleoptera, Coccinellidae)

Effects of two different mating regimes on sperm precedencein the two-spot ladybird, Adalia bipunctata, were studied usingthe polymorphic gene for melanism as a marker for paternity.Virgin nonmelanic females (homozygous recessive) were matedto nonmelanic male(s) and then, after laying fertilized eggs,were mated to a melanic male of known genotype. The resultsafter the two successive single matings showed a highly variabledegree of paternity of the second male. Initial multiple matingwith nonmelanic males did not alter the pattern of paternityafter the subsequent single mating with a melanic male, butit had two other effects: (1) the female showed an increasein rejection behavior, and (2) a longer copulation was requiredfor high success of the melanic male. Additional observationsin which families were reared from beetles collected in copulain the field demonstrated that sperm competition also occursunder natural conditions. The outcome of the competition wasvariable with frequent sperm mixing.     

The Immediate Source of the Oviposition-Deterring Pheromone Produced by Larvae of Adalia bipunctata (L.) (Coleoptera, Coccinellidae)

As is the case for other insects ovipositing on or in resources that are limited in time and/or space, the two-spot ladybird beetle, Adalia bipunctata (L.) produces an oviposition-deterring pheromone (ODP), which is produced by the larval stages. Foraging larvae touch the substrate with their tarsi and the anal disk on the tenth abdominal segment. The aim of this paper was to determine whether the ODP produced by larvae was deposited by the tarsi or the anal disk. Fourth instar larvae either had their anal disk and tarsi, or anal disk, or tarsi coated with a water-soluble mounting medium. Larvae so treated were allowed to walk on filter paper that was subsequently presented to gravid females. The tracks of larvae that had both their tarsi and anal disk masked did not inhibit oviposition. However, the tracks of larvae that had only their tarsi masked significantly inhibited oviposition but those of larvae that had only their anal disk masked did not. It is concluded that the ODP is deposited on the substrate by the anal disk on the tenth abdominal segment of larvae.     

The effects of two microsporidian pathogens on the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae)

Two-spotted lady beetles, Adalia bipunctata L. are available for biological pest control in North America. Lady beetles are known to host microsporidia and although these pathogens are able to infect more than one host under laboratory conditions, little is known regarding the effects of more than one microsporidian pathogen on host fitness. In this study, egg cannibalism was used to examine the effects of the microsporidium Tubulinosema hippodamiae from Hippodamia convergens and an undescribed microsporidium from A. bipunctata (alone and in combination) on A. bipunctata host fitness (larval development and mortality, sex ratio, adult fecundity and longevity). Development was prolonged significantly for larvae that were infected with the undescribed microsporidium but T. hippodamiae had no effect and as a result, conclusions could not be made regarding the effects of both pathogens on larval development. The two microsporidia had no effect on sex ratios (1♀:1♂) or on adult fecundity and longevity. Spores were detected in the majority of smear preparations of individuals that were fed microsporidia-infected eggs and molecular analysis confirmed the identity of both pathogens in sampled individuals. T. hippodamiae spores were smaller than spores of the undescribed microsporidium (3.76±0.03×2.32±0.02 μm and 5.43±0.06×2.75±0.03 μm, respectively) and although the former stained less intensely than did those of latter, spores of the two pathogens are difficult to differentiate when examined by light microscopy alone. The ability of some microsporidia to infect more than one lady beetle host makes it difficult to conclude with certainty as to the number of species that are present in infected Adalia when specimens are examined solely by light microscopy.     

Characterization of the alimentary canal of the aphidophagous ladybird,Adalia bipunctata (Coleoptera: Coccinellidae): anatomical and histological approaches

The alimentary canal of the two‐spot ladybird Adalia bipunctata (Linnaeus) (Coleoptera: Coccinellidae) presents the foregut (stomodeum), the midgut (mesenteron) and the hindgut (proctodeum). The shortest region is the foregut and the longest is the midgut. The relative proportions of the main regions were found to be similar for males and females. In the foregut it was possible to distinguish the pharynx, the esophagus and the proventriculus but no crop. The hindgut is composed of the ileum, rectum and rectal canal. Generally the organ width is similar for males and females, but females presented a wider proventriculus. The epithelium of the foregut varied from squamous to simple cuboidal and columnar. In the midgut the epithelium is simple columnar with goblet and regenerative cells. The epithelium of the hindgut varied from simple cuboidal to squamous. Females presented thicker midgut epithelium whereas males presented thicker epithelium in the esophagus. The anatomy of the alimentary canal of A. bipunctata seems to conform to its carnivorous and recent phylogenetic status within the family Coccinellidae.     

Effects of Aphid Prey on Larval Development and Mortality of Adalia bipunctata and Coccinella septempunctata (Coleoptera: Coccinellidae)

Developmental time and mortality rate of Adalia bipunctata (L.) and Coccinella septempunctata L. (Coleoptera: Coccinellidae) were determined when feeding on five aphid species. Metopolophium dirhodum (Walker), Sitobion avenae (F.), Rhopalosiphum padi (L.), Hyalopterus pruni (Geoffr.) and Myzus cerasi F. (Homoptera: Aphididae) are widespread in Tekirda?, Turkey. Tests were carried out in a controlled environmental chamber (25±1°C temperature, 65±5% relative humidity and 16 h light:8 h dark period). Developmental times for A. bipunctata and C. septempunctata larvae varied significantly depending on species of aphid prey (P<0.05). Development time (±S.E.) varied from 17.50±0.84 to 20.83±1.60 days for C. septempunctata and 16.7±0.76 to 20.7±1.03 days for A. bipunctata. Mortality of A. bipunctata (50%) and C. septempunctata (63%) were highest on H. pruni.     

Programmed cell death of the ovarian nurse cells during oogenesis of the ladybird beetle Adalia bipunctata (Coleoptera: Coccinellidae)

Programmed cell death (PCD) is an evolutionary conserved and genetically regulated form of cell death, in which the cell plays an active role in its own demise. It is widely recognized that PCD can be morphologically classified into three major types: type I, known as apoptosis, type II, called autophagy, and type III, specified as cytoplasmic cell death. So far, PCD has been morphologically analyzed in certain model insect species of the meroistic polytrophic ovary-type, but has never been examined before in insects carrying meroistic telotrophic ovaries. In the present study, we attempted to thoroughly describe the three different types (I, II and III) of PCD occurring during oogenesis in the meroistic telotrophic ovary of the Coleoptera species Adalia bipunctata, at different developmental ages of the adult female insects. We reveal that in the ladybird beetle A. bipunctata, the ovarian tropharia undergo age-dependent forms of apoptotic, autophagic and cytoplasmic (paraptotic-like) cell death, which seem to operate in a rather synergistic fashion, in accordance with previous observations in Diptera and Lepidoptera species. Furthermore, we herein demonstrate the occurrence of morphogenetically abnormal ovarioles in A. bipunctata female insects. These atretic ovarioles collapse and die through a PCD-mediated process that is characterized by the combined activation of all three types of PCD. Conclusively, the distinct cell death programs (I, II and III) specifically engaged during oogenesis of A. bipunctata provide strong evidence for the structural and functional conserved nature of PCD during insect evolution among meroistic telotrophic and meroistic polytrophic ovary-type insects.     

Effects of food and temperature on development,fecundity and life‐table parameters of Adalia bipunctata (Coleoptera: Coccinellidae)

Development, reproduction and life tables of Adalia bipunctata (L.) were studied at three temperatures (19, 23 and 27°C) on a mixture of frozen pollen and Ephestia kuehniella Zeller eggs as a factitious food and on the aphids Myzus persicae (Sulzer) and Acyrthosiphon pisum (Harris) as natural foods. Development time of A. bipunctata on all tested diets decreased with increasing temperature. Mortality was lowest at 23°C, averaging 44.5%, 42.6% and 24.3% on factitious food, A. pisum and M. persicae respectively. The shortest developmental time from egg to adult at this temperature was observed on factitious food (18.55 days). However, the factitious food was inferior to the aphid diets in terms of reproduction, yielding the longest pre‐oviposition period, shortest oviposition period and lowest fecundity. The mean oviposition rate at 23°C varied from 19.94 to 25.03 eggs day^?1 on factitious food and M. persicae respectively. The intrinsic rate of increase (r_m) on different foods increased with increasing temperature and ranged from a minimum of 0.08 females/female/day on factitious food (19°C) to a maximum of 0.18 females/female/day on A. pisum (27°C). The results suggest that a mixture of E. kuehniella eggs and pollen fully support development of A. bipunctata larvae and can be used as an alternative to live aphids in the mass rearing of the pre‐imaginal stages of the predator. However, reproductive performance of a laboratory population may be better on aphids than on the factitious food.     

The Stockholm populations of Adalia bipunctata (L) (Coleoptera: Coccinellidae)--a case of extreme female-biased population sex ratio

The genetic composition and sex ratio in the Stockholm populations of Adalia bipunctata have been studied. The overall frequency of melanics is 3.2%, which is significantly lower than in the populations of St. Petersburg and other large cities along the Baltic Sea. The secondary sex ratio in the Stockholm populations is female-biased 82:18. More than half of A. bipunctata females are infected with the male-killing Spiroplasma bacterium. Beetles of the co-existing species Adalia decempunctata are infected with a different bacterium belonging to the genus Rickettsia.     

Relative suitability of the common pistachio psyllid,Agonoscena pistaciae (Hemiptera: Aphalaridae), as prey for the two-spotted ladybird,Adalia bipunctata (Coleoptera: Coccinellidae)

The suitability of Agonoscena pistaciae Burckhardt & Lauterer as a prey for Adalia bipunctata (Linnaeus) was evaluated by studying the predator’s development and reproduction on this species in comparison to reference diets of nymphs of Myzus persicae (Sulzer) and eggs of Ephestia kuehniella Zeller. Both larval and adult A. bipunctata fed voraciously on A. pistaciae. The development time of the ladybird was shorter when fed on M. persicae and A. pistaciae and longer on E. kuehniella. The survival rate was 87% on M. persicae and 85% on A. pistaciae, both significantly greater than on E. kuehniella eggs (63%). The ladybirds were heaviest at eclosion and their fecundity was higher on M. persicae than on A. pistaciae or E. kuehniella. Both the aphid and psyllid diets yielded higher R₀, r_m values and lower T and DT values than E. kuehniella eggs. Based on total development time, immature survival and adult fecundity, the relative suitability for A. bipunctata was M. persicae > A. pistaciae > E. kuehniella. When ladybirds were reared on psyllids, they showed no preference between aphid or psyllid diets, but when raised on M. persicae, they preferred an aphid diet. A field experiment showed that A. bipunctata preferred to oviposit on pistachio trees at a height of 150–200 cm, i.e. towards the top. The results indicate that A. pistaciae constitutes a complete food for A. bipunctata, supporting both completed development and successful reproduction.     

Variability of the mitochondrial gene for cytochrome oxidase I within the Adalia bipunctata species and within species of ladybird beetles (Coleoptera: Coccinellidae)

Intergeneric, interspecific, and intraspecific genetic variation of the 310-bp 3'-end region of the mitochondrial gene of cytochrome oxidase I (COI) has been assessed in ladybirds (Coleoptera: Coccinnellidae). The phylogenetic distances between eight species of ladybirds have been determined. Mitochondrial DNA (mtDNA) nucleotide sequences have been compared in Adalia bipunctata L. differing in the elytron and pronotum colors that have been sampled from several geographically remote populations. The taxonomic statuses of two morphs from the genus Adalia, A. bipunctata bipunctata and A. bipunctata fasciatopunctata, have been identified.     

Development and reproduction of Adalia bipunctata on factitious and artificial foods

The native coccinellid Adalia bipunctata (L.) (Coleoptera: Coccinellidae) may be an alternative to exotic species like Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) for the biological control of aphid pests in Europe. The availability of adequate factitious or artificial foods may help optimize its mass production. This study examines the nutritional value of Ephestia kuehniella Zeller (Lepidoptera: Phycitidae) eggs plus bee pollen, pea aphids Acyrthosiphum pisum (Harris) (Hemiptera: Aphididae) and mixtures of bee pollen and cysts of Artemia franciscana Kellogg (Branchiopoda: Artemiidae) and/or a lyophilized artificial diet based on bovine meat and liver. Reproducing adults of A. bipunctata were obtained on all diets tested, but immature survival, adult weights, development times and reproductive rates differed among diets. Over 84% of first instars fed on E. kuehniella eggs plus pollen or aphids survived to adulthood. Feeding predator larvae on pollen combined only with A. franciscana cysts or artificial diet yielded 40–55% immature survival, but survival increased to 74% when all of these components were mixed. Adult weights of A. bipunctata on the mixtures of pollen, A. franciscana cysts and/or artificial diet were 55–75% of those on aphids or on E. kuehniella eggs plus pollen. Lifetime fecundity was superior on E. kuehniella eggs plus pollen (1,864 eggs) to that on the other diets (264–889 eggs). The use of mixtures of plant and animal foods for A. bipunctata and other predators may contribute to increasing the cost-effectiveness of commercial mass production by reducing inputs of natural prey like aphids, or of nutritious but expensive factitious foods like lepidopteran eggs.     

Searching by Adalia bipunctata (L.) (Coleoptera: Coccinellidae) and escape behaviour of its aphid and cicadellid prey on lime (Tilia×vulgaris Hayne)

• 1 The paper describes the behavioural interactions between searching larvae of Adalia bipunctata and its aphid and cicadellid prey on lime (Tilia×vulgaris Hayne).
• 2 The frequency with which the predator achieves contact with cicadellid nymphs of differing ages is related to direction of predator approach and predator perception by the cicadellid.
• 3 The success of a coccinellid in contacting and capturing its aphid prey is related to the predator's size and direction of approach, the perception of the predator by an aphid and the latter's ability to escape, the effectiveness of which is discussed.

     

Influence of some pesticides on mortality and fecundity of the aphidophagous coccinellid Adalia bipunctata L. (Col., Coccinellidae)

The influence of 30 pesticides (insecticides, acaricides and fungicides) on different stages of Adalia bipunctata was evaluated under laboratory conditions by: (1) immersing individuals for 5 s in the pesticide solution; (2) placing the second and fourth instar larvae on leaves picked from trees treated with the pesticide; and (3) feeding adult coccinellids with aphids contaminated by a recommended concentration of the pesticide. Fenpropathrin, alphacypermethrin, esfenvalerate, acrinathrin, phosalone and propoxur + methoxychlor caused high mortality (up to 100%) not only by direct contact but also as fresh residues on leaves, or even 28 days after application. The mortality also varied with stage and mode of treatment. Feeding with aphids contaminated by fenpropathrin, clofentezine, hexythiazox, brompropylate and vinclozolin decreased the coccinellid fecundity.     

Bacteria in ovarioles of females from maleless families of ladybird beetles Adalia bipunctata L. (Coleoptera: Coccinellidae) naturally infected with Rickettsia,Wolbachia, and Spiroplasma

Ovarioles were found to be infected with Spiroplasma, Wolbachia, and Rickettsia in Adalia bipunctata females with maleless progeny in different natural populations. Ooplasm was infected with few Wolbachia bacteria. In ooplasm infected by Rickettsia, bacteria were present in small foci. Spiroplasmas were found encapsulated into ooplasm from the wider intercellular spaces between epithelial and oocyte cells. The cytoplasm of follicular epithelia infected with Rickettsia was heavily destroyed, but the nucleus was intact and free from bacteria. The essential feature of follicular epithelium cells from Spiroplasma and Wolbachia infected A. bipunctata females was inclusions of three types: crystalline, filaments, and concentric myelin-like lamellae. Observations of smears prepared from ovaries of A. bipunctata from natural populations revealed a low concentration of bacteria within a microscopy field (less 10 bacteria) in more than 90% of specimens, and only a few ovaries were heavily infected. Two different ways of bacterial invasion of the oocyte are suggested: Spiroplasma-like, through the intercellular spaces in the epithelium and Rickettsia-like, through the cytoplasm of follicular epithelium cells. Bacteria were not found in germarium zones and we suggest that each follicle is infected from haemolymph.     

Yellow Traps Can Be Used to Monitor Populations of Coccinella transversalis (F.) and Adalia bipunctata (L.) (Coleoptera: Coccinellidae) in Cotton Crops

During 1992–4, square (30 times 30 cm) sticky traps of various colours were used on a commercial cotton farm to trap adults of Coccinella transversalis and Adalia bipunctata which are both major predators of Helicoverpa spp. Both insects were attracted most to yellow traps which also reflected the most visible light between 500 nmand 600 nm(where green foliage reflects most light). When yellow was diluted with white to produce yellow-white hues, the light reflected between 500 nm and 600 nm was reduced and the numbers of C. transversalis and A. bipunctata adults caught on these traps were also significantly reduced. This suggests that C. transversalis and A. bipunctata adults can discriminate foliage-like hues (500–580 nm) from non-foliage-like hues (<500 nm and >580 nm) and are attracted to colours that suggest the foliage of host plants that may harbour their prey. Yellow sticky traps placed 25–50 cm above ground caught significantly more C. transversalis and A. bipunctata adults than those placed at 75–150 cm and are the most appropriate traps to monitor populations of C. transversalis and A. bipunctata adults in cotton farms.     

Biological traits and life table of the exotic Harmonia axyridis compared with Hippodamia variegata,and Adalia bipunctata (Col., Coccinellidae)

Abstract: As part of an environmental risk assessment study of exotic natural enemies used in inundative biological control, life‐history characteristics of Harmonia axyridis (Pallas), Hippodamia variegata (Goeze) and Adalia bipunctata (L.) (Col., Coccinellidae) were quantified under laboratory conditions at 25°C on Myzus persicae (Sulzer) as prey. Comparative studies showed significant differences among pre‐adult development times: H. axyridis developed slower ( = 19.8 days) than H. variegata ( = 18.1 days) and A. bipunctata ( = 18.4 days). Differences were also evident in the duration of egg, larval and pupal stages. No measurable differences among the three species were found for fecundity, oviposition rate and adult longevity. Harmonia axyridis exhibited the longest pre‐oviposition ( = 7.4 days) and interoviposition ( = 3.6 days) periods and the shortest oviposition period ( = 13.7 days). The Bieri model was used to describe age‐specific fecundity for the three species of coccinellids. The intrinsic rate of increase (r_m), net reproductive rate (R₀) and mean generation time (T) were higher for H. variegata (r_m = 0.114, R₀ = 52.75, T = 41.88 days) than for H. axyridis (r_m = 0.089, R₀ = 26.27, T = 38.81 days) or A. bipunctata (r_m = 0.081, R₀ = 18.49, T = 40.06 days). Our findings show that the biological traits of H. axyridis do not seem to be factors that may contribute to the invasiveness of this coccinellid.     

Expansion of the geographical distribution of an exotic ladybird beetle, Adalia bipunctata (Coleoptera: Coccinellidae), and its interspecific relationships with native ladybird beetles in Japan

The first record of the exotic ladybird beetle, Adalia bipunctata (Coleoptera; Coccinellidae), in Japan was in 1993 at Osaka Nanko Central Park. Since that time, studies on the life history and geographical distribution of A. bipunctata have been ongoing, and its establishment in the Osaka Nanko area has been confirmed. A. bipunctata is a predacious ladybird beetle and a member of a guild that overlaps in habitat and prey with that of native ladybird beetles such as Harmonia axyridis and Menochilas sexmaculatus. We investigated the distribution of A. bipunctata and its interspecific relationships with native predacious ladybird beetles. In some areas, A. bipunctata was dominant in interspecific relationships with native ladybird beetles. For the first 10 years after A. bipunctata was discovered, it occurred only in the Osaka Nanko area, but the present geographical distribution indicates that it has expanded its range. Though the population density of this species was highest at the area recorded first, and tended to decrease in inverse proportion to the distance from Osaka Nanko Central Park, a satellite occurrence was observed in a remote area. The numbers of aphid and tree species (leaf shelter for aestivation and over-wintering) utilized by A. bipunctata have recently increased. Such increases will cause the rate of distribution of A. bipunctata to accelerate. Interspecific competition between H. axyridis and A. bipunctata, which occurs earlier than H. axyridis, may be avoided by desynchronization of the occurrence seasons, and another common predacious ladybird beetle, Coccinella septempunctata, may escape interspecific competition by habitat segregation.     

Role of photoperiod in the development and reproduction of Harmonia axyridis (Coleoptera,Coccinellidae)

To improve the laboratory mass rearing and the winter greenhouse use of the multicoloured Asian lady beetle Harmonia axyridis (Pallas) (Coleoptera, Coccinellidae), the effects of photoperiod on the development and fecundity of H. axyridis were investigated at 20°C and photoperiods ranging from 0L:24D to 24L:0D. We foun'd photoperiod to significantly affect the pre-imaginal development and reproduction of H. axyridis. The development of the pre-imaginal stage was significantly faster at shorter photoperiods (0–14?h) than at longer ones (16–24?h). The proportion of females laying eggs within the first 30 days after eclosion, the mean number of eggs per ovipositing female, and the long axial length of the first oocyte were all lower at shorter photoperiods (6–12?h) than at longer ones (14–24?h). These results suggest that adult H. axyridis may encounter problems in preying and reproducing in the winter conditions of unheated and unilluminated greenhouses in areas with temperatures lower than 20°C and day lengths shorter than 12?h.     

The consequences of egg cannibalism inAdalia bipunctata [Coleoptera: Coccinellidae]

When eggs ofAdalia bipunctata L. are offered to larvae of their own species, these larvae are able to develop to adults. Reducing the daily egg supply results in decreased larval survival and pupal weight and especially fecundity of the adult females. The duration of larval development is significantly increased, the longevity of adults is shortened.