Biological Parameters for Four Coccinellid Species in Central Saudi Arabia

Developmental and reproductive rates ofAdonia variegataGoeze,Coccinella novemnotataHerbst,C. septempunctataL., andC. undecimpunctataL. were studied in wheat and barley in Central Saudi Arabia. Beetles were reared in the laboratory at 25 ± 2°C onBrevicoryne brassicae(L.) andRhopalosiphum padiL.A. variegataandC. undecimpunctatahad significantly higher egg hatching (X = 81.8 and 74.5%), adult longevity (X = 71.8 and 70.0 days), and survival (X = 61.8 and 61.5%), respectively.Coccinella undecimpunctatahad the highest fecundity (X = 370.5 eggs/female) and longest oviposition period (X = 29.8 days).C. septempunctataexhibited the lowest values for these biological parameters. No differences were evident in the total developmental time or egg and pupal duration, although species differences occurred in the larval duration. Larvae ofA. variegatadeveloped faster (X = 11.8 days) than Larvae ofC. septempunctata(X = 12.0 days),C. undecimpunctata(X = 12.2 days), orC. novemnotata(X = 13.1 days). The intrinsic rate of increase (r_m) and predicted population density were higher forC. undecimpunctata(X = 0.093 and 98553) after 60 days than forC. novemnotata(X = 0.088 and 59405),C. septempunctata(X = 0.086 and 35033), orA. variegata(X = 0.082 and 37991), respectively.     

Comparative Prey Suitability ofOstrinia nubilalisEggs andAcyrthosiphon pisumforColeomegilla maculata

The effects ofOstrinia nubilalis(Hübner) (Lepidoptera: Pyralidae) eggs andAcyrthosiphon pisum(Harris) (Homoptera: Aphididae), when provided as single prey species and in combination, on life history characteristics ofColeomegilla maculataDeGeer (Coleoptera: Coccinellidae) larvae and adults were quantified. Preimaginal development was not influenced by the larval prey regime; development at 26 ± 1°C was completed in approximately 13.5 days onO. nubilaliseggs,A. pisum,orA. pisumalternated daily withO. nubilaliseggs. The resulting adults weighed 13.0, 10.7, and 12.5 mg when reared onO. nubilaliseggs,A. pisum,andA. pisumalternated daily withO. nubilaliseggs, respectively. Eighteen percent of the individuals died when reared onA. pisum,28% died when reared onO. nubilaliseggs, and 22% died when fedA. pisumalternated daily withO. nubilaliseggs. Seven adult diet combinations, based on diet regimes of larvae and adults, did not cause significant differences in preoviposition period, interoviposition period, and the number of days on which eggs were laid. Total fecundity was influenced both by larval and adult diet. The diet that resulted in highly fecund females wasA. pisumalternated daily withO. nubilaliseggs for larvae andO. nubilaliseggs for adults. FemaleC. maculatafedO. nubilaliseggs had the highest intrinsic rate of increase and net reproductive rate.     

Interspecific variation in the escape responses of aphids: effect on risk of predation from foliar-foraging and ground-foraging predators

A series of laboratory experiments was conducted to determine the effect of interspecific differences on prey defensive behavior on the susceptibility of two aphid species (Acyrthosiphon pisum and A. kondoi) to a ground-foraging predator, Harpalus pennsylvanicus, and a foliar-foraging predator, Coccinella septempunctata. These organisms are representative of a biologically and economically important predator/prey system in alfalfa. The primary defensive behavior of both aphid species toward C. septempunctata was to “drop” from the plant. Both aphid species were significantly more likely to drop from the plant in the presence of C. septempunctata. However, when C. septempunctata was present, a significantly lower proportion of A. kondoi individuals dropped (0.42 ± 0.07) compared to A. pisum (0.73 ± 0.08). As a result of their lower propensity to drop from the plant A. kondoi individuals are significantly more likely to be consumed by C. septempunctata. Conversely, the higher propensity of A. pisum individuals to drop increased their susceptibility to ground-foraging predators. When A. pisum was the prey species, ground-foraging predators made a significant contribution to overall aphid suppression and there was a significant synergistic interaction between ground and foliar-foraging predators. When A. kondoi was the prey there was no interaction between the predator species. As either a cause or consequence of its higher propensity to drop, A. pisum seems to be more adapted for survival and dispersal off the plant. In comparison to A. kondoi individuals, A. pisum individuals relocate plants more quickly (63 ± 41 s vs. 164 ± 39 s), disperse farther (18 ± 1.7 cm vs. 13 ± 0.66 cm), and survive longer (37 ± 2.0 h vs. 25 ± 2.0) off the plant. This study demonstrates the importance of prey defensive behavior in determining the susceptibility of a prey species to a multiple-predator complex. Received: 24 February 1997 / Accepted:17 December 1997     

Interference and competitive behaviour of the aphid predators,Chrysoperla carnea andCoccinella septempunctata in the laboratory

Interference and competition betweenChrysoperla carnea (Stephens) andCoccinella septempunctata L. was investigated in the absence and presence of aphid prey. When larvae of similar vigour encountered each other,C. carnea larvae were superior toC. septempunctata. Otherwise the larger of 2 individuals always killed the smaller. In the absence of preyC. carnea adults were attacked by their own 2nd and 3rd instar larvae as well as by 3rd instar larvae ofC. septempunctata. In all encounters the adults ofC. septempunctata were superior. Since the eggs ofC. carnea are protected to some extent by being on egg stalks, they were less susceptible to cannibalism and predation thanC. septempunctata eggs which are deposited in batches directly on plant leaves. In the presence of prey cannibalism and predation were reduced, especially between larvae. Only eggs and 1st instar larvae were endangered. In the present experimentsC. carnea showed a slight superiority overc. septempunctata. Paper presented at the 17th International Congress of Entomology held in August 20–26 1984 in Hamburg, F.R. Germany.     

The foraging behaviors of larvae of the ladybird beetle, <Emphasis Type="Italic">Coccinella septempunctata</Emphasis> L., (Coleoptera: Coccinellidae) towards ant-tended and non-ant-tended aphids

The foraging behaviors of larvae of the ladybird, Coccinella septempunctata L., towards both the ant-tended aphid, Aphis craccivora Koch, and the non-ant-tended aphid, Acyrthosiphon pisum Harris, were investigated in the field and in laboratory experiments. Although there were no differences in the development and growth of the ladybird larvae that preyed on either Ac. pisum or Ap. craccivora, the foraging efficiency of the ladybird larvae that preyed on Ap. craccivora was higher than that of the ladybird larvae that preyed on Ac. pisum in the absence of ants. This result was explained by the fact that the number of Ac. pisum that escaped by dropping off the plant was conspicuously larger than the number of Ap. craccivora that escaped in this fashion and derived from the non-ant-attendance associated with Ac. pisum. In the laboratory experiments, fewer ladybird larvae climbed onto a plant with Ap. craccivora in the presence of ants than onto a plant with Ac. pisum in the absence of ants. The ladybird larvae did not switch from foraging for Ap. craccivora to foraging for Ac. pisum, even after suffering attacks by ants on a plant with Ap. craccivora, and it would appear that ladybird larvae are unable to remember where they have previously been attacked by ants. These results could explain why the ladybird larvae in the field more frequently visited Vicia angustifolia plants with Ap. craccivora than those with Ac. pisum and made more visits when ants were absent than when they were present.     

Stage and age-specific predation in four aphidophagous ladybird beetles

In the present study, stage- and age-specific predatory patterns and nutritional ecology attributes of four co-occurring aphidophagous ladybirds, namely, Coccinella septempunctata (L.), Coccinella transversalis F., Cheilomenes sexmaculata (F.) and Propylea dissecta (Mulsant) on pea aphid, Acyrthosiphon pisum (Harris) were investigated. Despite their lower consumption rates, smaller ladybirds (C. sexmaculata and P. dissecta) and earlier instars were efficient converters of aphid prey with higher relative growth rates, over the respective larger ladybirds (C. septempunctata and C. transversalis) and fourth instars. The consumption rates of pea aphids by the larvae increased with stage, but with a decline in the later part of the fourth instars, just prior to pupation. Adult females of early age groups (between 2 and 7 days) had higher consumption rates than later age groups in all the four species. Further in adult females, consumption rates decrease with increase in age, but without significant changes in conversion efficiencies and relative growth rates.     

Aggregation of polyphagous predators in response to multiple prey: ladybirds (Coleoptera: Coccinellidae) foraging in alfalfa

The spatial distribution of polyphagous predators may often reflect the integration of aggregative responses to local densities of multiple species of prey, and as such may have consequences for the indirect linkages among the prey sharing these predators. In a factorial field experiment in which we manipulated local prey densities within a field of alfalfa in Utah (USA), we tested whether aphidophagous ladybirds would aggregate not only in response to their primary aphid prey, but also in response to an abundant alternative prey, the alfalfa weevil (Hypera postica [Gyllenhal]). Native North American ladybirds (primarily Hippodamia convergens Guerin and H. quinquesignata quinquesignata [Kirby]) responded only to spatial variation in aphid density. In contrast, the introduced ladybird, Coccinella septempunctata L., aggregated also at local concentrations of the weevil late in the experiment when weevil density was high and aphid density was relatively low throughout all experimental plots. The results support the hypothesis that C. septempunctata is more responsive than are native ladybirds to the availability of alternative prey in alfalfa, which may account in part for the displacement of native ladybirds from alfalfa by the introduced species as aphid numbers have declined. The differing responses of the native and introduced ladybirds to spatial patterns of the alternative prey underscore the importance of extending the study of predator aggregation to understand better how polyphagous predators distribute themselves in response to spatial patterns of multiple species of potential prey.     

Evaluation of four co-occurring ladybirds for use as biocontrol agents of the pea aphid,Acyrthosiphon pisum (Homoptera: Aphididae)

The potential of four co-occurring ladybirds, Coccinella septempunctata (L.), Coccinella transversalis (F.), Cheilomenes sexmaculata (F.), and Propylea dissecta (Mulsant), as predators of the pea aphid, Acyrthosiphon pisum (Harris) was investigated. Larger ladybirds were more voracious while smaller ones had higher consumption indices and were more efficient converters of food.     

七星瓢虫基础研究现状

七星瓢虫对蚜虫等农林业中的重要害虫有较强的控制作用,利用七星瓢虫进行控害的生物防治技术正在逐步推广.本文就七星瓢虫的生物学特性、捕食、对农药的反应以及人工饲养等方面进行综述:七星瓢虫幼虫随龄期增长逐渐出现黄斑,温湿度对生长发育影响较大,以成虫越冬,有滞育现象.七星瓢虫捕食性强,捕食对象较多,包括多种蚜虫、木虱、蚧虫、粉...     

Growth and development of immature life stages ofPropylaea 14-punctata L. andCoccinella 7-punctata L. [Col.: Coccinellidae] simulated by the metabolic pool model

The conversion of aphid prey tissue (Acyrthosiphon pisum Harris) into predator biomass (immature life stages ofPropylaea 14-punctata L. andCoccinella 7-punctata L.) is calculated by plotting weight gain against assimilation (i.e. consumption minus egestion). This concept is added to the metabolic pool model byGutierrez et al. (1981) that enables the simulation of growth and development of a predator on a physiological basis. Physiological time is expressed in daydegrees above lower development thresholds for both species. Visual examination of observed and calculated values showed that the model satisfactorily describes the growth patterns of the above predators.      

Negative dietary effects of Colorado potato beetle eggs for the larvae of native and introduced ladybird beetles

Aphidophagous ladybird beetles (Coleoptera: Coccinellidae) are attracted to and feed heavily on aphids, but many species will also feed opportunistically on other prey that they encounter. In potatoes (Solanum tuberosum L.) in Washington State, USA, coccinellids feed on both green peach aphids (“GPA,” Myzus persicae Sulzer) and eggs of the Colorado potato beetle (“CPB,” Leptinotarsa decemlineata Say). The guild of aphidophagous ladybirds includes two native species, Hippodamia convergens Guérin-Méneville and Coccinella transversoguttata Brown. Recently, an introduced species, Coccinella septempunctata L., has invaded and apparently displaced its native congener. A second exotic, Harmonia axyridis Pallas, has colonized the area and is becoming more abundant. We compared larval development of each species on a monotypic diet of GPA, a monotypic diet of CPB eggs, or a mixed diet of both GPA and CPB eggs. Our goal was to answer two questions: (1) do larvae of the four ladybird species benefit from including CPB eggs in their diet and (2) do the four ladybird species differ in their ability to utilize CPB eggs as prey? No larva of any species completed development on a pure diet of CPB eggs, and survivorship was highest for all species when they fed on a pure diet of GPA. One native species, H. convergens, and one exotic species, H. axyridis, exhibited significantly lower survivorship on a mixed diet of both CPB eggs and GPA, compared to a pure GPA diet; H. axyridis also took longer to develop from egg to adult when both prey were provided. Survivorship of the two Coccinella spp. was not altered by the inclusion of CPB eggs with GPA, although CPB eggs lengthened the development time of C. transversoguttata. Adult size was not consistently affected by diet for any of the coccinellids. Overall, no ladybird species benefited from the inclusion of potato beetle eggs in its diet. The two Coccinella species responded similarly to the inclusion of CPB eggs, and so we would not expect any difference in the success of coccinellid larval development in potato fields following the replacement of C. transversoguttata by C. septempunctata. Hippodamia convergens and H. axyridis, the two species whose survivorship was depressed by combining CPB egg and aphid prey, were also the two species that consumed the greatest number of CPB eggs during successful larval development. A comparison of total egg consumption by each species cohort suggested that displacement of the other species by H. axyridis would not alter CPB biological control, because the higher per capita feeding rate by H. axyridis larvae compensated for individuals’ greater mortality risk on a diet including CPB eggs.     

Suitability of Aphis fabae, Myzus persicae (Homoptera: Aphididae) and Aleyrodes proletella (Homoptera: Aleyrodidae) as prey for Coccinella undecimpunctata (Coleoptera: Coccinellidae)

The suitability of Aphis fabae Scopoli, Myzus persicae Sulzer and Aleyrodes proletella L. as food sources for Coccinella undecimpunctata L. was evaluated by studying the impact of prey consumption on the predator’s population growth parameters and feeding parameters. Unlike A. proletella, A. fabae and M. persicae supported the development and reproduction of C. undecimpunctata. A. fabae and M. persicae were considered to be essential prey, whereas A. proletella was considered to be an alternative prey. Aphid species showed different degrees of suitability: M. persicae significantly decreased the pre-oviposition period and increased adult longevity, fecundity and fertility compared with A. fabae. Moreover, A. fabae represents a suitable diet for larval development, but is not a suitable food source for adult reproduction. The predator’s population growth parameters, R₀, r_m and λ were increased with M. persicae, whereas T decreased. We found that the 4th instar larvae were the most voracious, particularly when fed on M. persicae; nevertheless, with this prey daily weight gain and feeding efficiency of 4th instar larvae were similar to that of individuals fed with A. fabae.     

Effects of elevated CO2 on five plant-aphid interactions

We investigated interactions between five species of phloem-feeding aphids (Homoptera: Aphididae) and their host plants at elevated CO₂; Acyrthosiphon pisum (Harris) on Vicia faba L., Aphis nerii Boyer de Fonscolombe on Asclepias syriaca L., Aphis oenotherae Oestlund on Oenothera biennis L., Aulacorthum solani (Kaltenbach) on Nicotiana sylvestris Speg. & Comes and Myzus persicae (Sulzer) on Solanum dulcamara L. Host plants grown at elevated CO₂ generally had greater biomass, leaf area and C:N ratios than those grown at ambient CO₂, while plants with aphids had lower biomass and leaf area than those without aphids.The responses of aphid populations to elevated CO₂ were species-specific with one species increasing (M. persicae), one decreasing (A. pisum), and the other three being unaffected. CO₂ treatment did not affect the proportion of alate individuals produced. In general, aphid abundance was not significantly related to foliar nitrogen concentration.We performed separate analyses to test whether either aphid presence or aphid abundance modified the response of host plants to elevated CO₂. In terms of aphid presence, only three of the potential 15 interactions (five aphid species x three plant traits) were significant; A. solani slightly modified the response of the plant biomass to elevated CO₂ and M. persicae affected the response of leaf area and allocation. In terms of aphid abundance, only two of the potential 15 interactions were significant with A. nerii modifying the plant response to CO₂ in terms of total leaf area and allocation.We conclude that, in contrast to other insect groups such as leaf chewers, populations of most phloem-feeders may not be negatively affected by increased CO₂ concentrations in the future. The reasons for this difference include the possibility that aphids may be able to compensate for changes in host plant quality by altering feeding behaviour or by synthesizing amino acids. In addition, there is little evidence that aphid herbivory, even at high levels, will substantially modify the response of plants to elevated CO₂.     

The co-occurrence of an introduced biological control agent (Coleoptera: <Emphasis Type="Italic">Coccinella septempunctata</Emphasis>) and an endangered butterfly (Lepidoptera: <Emphasis Type="Italic">Lycaeides melissa samuelis</Emphasis>)

Whether a biological control agent presents a non-target risk to a native species depends if they co-occur spatially and temporally, and if the agent will harm the native species. We sampled two study sites during 1993 in Minnesota and Wisconsin to survey predators and parasitoids of the extant populations of the United States federally endangered Karner blue butterfly, Lycaeides melissa samuelis. We found the introduced coccinellid Coccinella septempuntata co-occurring spatially and temporally with eggs, larvae and adults of L. m. samuelis. The two species were also observed together on the latters sole host plant, Lupinus perennis, and in Wisconsin, an adult C. septempunctata was observed consuming second instar larvae of L. m. samuelis. Using a simple model to hypothesize the risk that C. septempunctata presents to L. m. samuelis, we showed that increases in predator density could greatly increase mortality to L. m. samuelis. At these sites, C. septempunctata were reproducing and had access to summer aphids and suitable overwintering habitat. Nearby agricultural crops could provide spring aphids for oogenesis, and assist with C. septempunctata population build-up. Maintaining a minimum isolation distance between agricultural crops known to harbor aphids and extant L. m. samuelis populations may need to be considered as part of the butterfly management program.     

Alterations in foraging behavior of Coccinella septempunctata and Propylea japonica mediated by a novel defended prey affect their predatory potential

Generalist aphidophagous coccinellids have to cope with novel prey aphids in environments that are changing rapidly because of anthropogenic activity. The goldenrod aphid, Uroleucon nigrotuberculatum (Olive) (Hemiptera: Aphididae), is a noxious prey, which was recently introduced into Japan. It is a major prey for the native Japanese predators Coccinella septempunctata bruckii Mulsant and Propylea japonica (Thunberg) (both Coleoptera: Coccinellidae) in early summer on patches of solidago, Solidago altissima L. (Asteraceae). Prey preference of these coccinellids between this aphid and a native suitable prey aphid, Megoura crassicauda Mordvilko (Hemiptera: Aphididae), as well as their foraging behavior were studied for a better understanding of the negative impacts of the noxious novel aphid. Coccinella septempunctata initially preferred the novel prey, but later switched to the native prey, M. crassicauda; P. japonica had no preference for either prey. Feeding time of the first instars of C. septempunctata on U. nigrotuberculatum was significantly longer than that of P. japonica. The foraging bouts of fourth instars of C. septempunctata were significantly longer on U. nigrotuberculatum than on M. crassicauda, whereas only the feeding time of fourth instars of P. japonica on U. nigrotuberculatum was significantly longer than on M. crassicauda. Both coccinellids consumed less of U. nigrotuberculatum than of M. crassicauda. Thus, solidago patches infested by U. nigrotuberculatum may present an ecological trap, especially for C. septempunctata.     

Investigations of the host feeding preferences ofSitona weevils found commonly on white clover (Trifolium repens) in the UK

A series of laboratory and field studies were done to evaluate a range of leguminous plant species for their feeding potential by adult weevils of the genusSitona Germar. (Coleoptera: Curculionidae). Three species ofSitona, S. lineatus L.,S. flavescens Marsh. andS. hispidulus F. all of which are found commonly on white clover (Trifolium repens L.) in the UK were offered a range of 11 legume species,T. repens (white clover, cv. Olwen),T. pratense L. (red clover, cv. Marcom),T. fragiferum L. (strawberry clover, cv. Palestine),T. hybridum L. (hybrid clover, cv. Tetra),T. incarnatum L (crimson clover),T. dubium Sibth. (lesser yellow trefoil),Lotus corniculatus L. (birdsfoot-trefoil, cv. Leo),L. uliginosus Schkuhr. (large birdsfoot-trefoil),Melilotus alba Desr. (white melilot),Medicago sativa L. (lucerne, cv. Europe) andM. lupulina L. (black medick) in two laboratory experiments. The weevils were offered a choice of these legumes in one experiment whilst in the other they did not have a choice of food material. These legumes were also sown in the field and a number of measurements of damage, together with counts ofSitona spp., were made. In the laboratoryS. lineatus andS. hispidulus favoured some of the legumes to a greater or lesser extent than white clover.S. flavescens was more restricted in its feeding than the other two weevil species. In the field studyS. lineatus invaded the experimental area quickly and tended to favourMedicago spp. andMelilotus spp. Later in the yearS. flavescens dominated the sitona fauna on the experiment, with the exception of aggregations ofS. lineatus onM. sativa andM. alba. In a separate screen of 5 varieties of white clover (cvs Donna, Menna, Kersey, Olwen and Grasslands Huia), cv. Olwen appeared to be the most susceptible to sitona attack.     

The effect of rearing the ladybirdHarmonia axyridis onEphestia kuehniella eggs on the response of its larvae to aphid tracks

Larvae ofHarmonia axyridis Pallas (Col., Coccinellidae) exhibited two walking patterns during prey search. Extensive search occurred when searching for prey patches and was characterized by long linear paths and a fast speed. Intesive search, which appeared after the ingestion of a prey in a patch, resulted from a lowering of the linear speed and an increase in the number of stops and angular speed. When larvae reared on the aphidAcyrthosiphum pisum Harris (Hom., Aphidae) crossed an artificial substratum previously contaminated by this prey, they changed their path direction and adopted intensive search. They probably perceived aphid odor tracks and consequently modified their walking pattern. This gustatory capacity probably allowed very mobile larvae to locate prey patches more rapidly and improve encounter with preys in every patch.H. axyridis larvae reared on a substitute prey, the eggs ofEphestia kuehniella Zeller (Lep., Pyralidae), for more than a hundred generations, also changed their path orientation but retained extensive search. The weak response of these larvae to aphid tracks may have resulted from either a decrease in their sensitivity to gustatory aphid stimuli or their difficulty in associating aphid odor with aphid presence. These larvae needed more time and more preliminary encounters than larvae reared on aphids before catching prey.     

Effect of temperature on development, growth and feeding of Coccinella septempunctata and Hippodamia convergens reared on the tobacco aphid, Myzus persicae nicotianae

Preimaginal development, mortality, aphid consumption rate, and size and weight upon reaching the adult stage of the aphidophagous coccinellids Hippodamia convergens Guérin-Méneville and Coccinella septempunctata L. collected from Karditsa, central Greece, were examined at four constant temperatures (14, 17, 20 and 23 °C) and L16:D8. The coccinellids fed on the tobacco aphid, Myzus persicae nicotianae Blackman. Egg, larval and pupal mortality was highest at 14 °C reaching 85.0, 73.8 and 29.4% in H. convergens and 49.3, 75.4 and 58.8% in C. septempunctata, respectively. Total preimaginal development ranged from 57.2 to 70.4 days at 14 °C, and to 16.9 and 22.1 days at 23 °C in H. convergens and C. septempunctata, respectively. Heavier and larger adults of H. convergens were obtained at 17 and 20 ° C. In C. septempunctata temperature did not affect adult weight while the lowest size was observed at 14 and 17 °C. Day-degrees requirements for preimaginal development in H. corvengens were 212.9 above a developmental threshold of 11.0 °C. The corresponding values for C. septempunctata were 281.5 and 10.7 °C. In H. convergens total and daily aphid consumption ranged from 46.8 aphids at 14 °C to 85.0 aphids at 23 °C and from 1.5 aphids at 14 °C to 9.2 aphids at 23 °C, respectively. The corresponding values for C. septempunctata were 112.0 and 2.7 at 14 °C and 157.7 and 12.4 at 23 °C. The results show the high potential of both predators as biological control agents against the tobacco aphid. The knowledge obtained could be essential for their appropriate use and for the improvement of mass rearing systems.     

Influence of six aphid prey species on development and reproduction of a ladybird beetle, Coccinella septempunctata

Pre-imaginal development, immaturesurvival, and reproduction of a ladybird, Coccinella septempunctata Linnaeus, werestudied in response to six aphid species, Aphiscraccivora Koch, Aphis gossypii Glover,Aphis nerii Boyer de Fonscolombe,Lipaphis erysimi (Kaltenbach), Myzuspersicae (Sulzer) and Uroleuconcompositae (Theobald) to quantify theirrelative suitability as prey. Pre-adultdevelopment was shortest (13.93 ± 0.12 days)when fed on L. erysimi and longest(22.85 ± 0.10 days) on A. nerii. Immaturesurvival, adult emergence, growth index,relative growth rate, development rate, maleand female longevity, oviposition period,fecundity and hatching percent were maximal, i.e. 73.47 ± 0.89%, 90.07 ± 1.43%,8.62 ± 0.23, 1.52 ± 0.02, 0.07,81.10 ± 1.26 days, 85.70 ± 1.45 days,69.80 ± 1.32 days, 1764.10 ± 8.46,and 87.88 ± 1.05, respectively when C.septempunctata were fed on L. erysimi.The same parameters were minimal, i.e.43.86 ± 1.33%, 71.65 ± 2.75%,2.02 ± 0.08, 0.49 ± 0.02, 0.04,44.40 ± 1.39 days, 53.50 ± 1.00 days,16.40 ± 0.60 days, 203.20 ± 11.83, and48.68 ± 2.06, respectively on A. nerii. Theweights of different ladybird life stages weremaximal after feeding on L. erysimi and minimalon A. nerii. Regression analyses of thedata revealed linear relationships betweendevelopment rate and weight of adult; dailyprey consumption and relative growth rate; logweight of adult male and female; and longevityand fecundity of female. On the basis of thesefindings, the order of suitability of aphidspecies for C. septempunctata is L. erysimi >M. persicae > A. craccivora > A. gossypii >U. compositae > A. nerii. Thus, the presentinformation can be utilized for the massrearing of C. septempunctata by supplyingthe best food and can also help in theprediction of the relative abundance of theladybird on different aphid infestations in thefields.     

The analysis of core and symbiotic genes of rhizobia nodulating Vicia from different continents reveals their common phylogenetic origin and suggests the distribution of Rhizobium leguminosarum strains together with Vicia seeds

In this work, we analysed the core and symbiotic genes of rhizobial strains isolated from Vicia sativa in three soils from the Northwest of Spain, and compared them with other Vicia endosymbionts isolated in other geographical locations. The analysis of rrs, recA and atpD genes and 16S–23S rRNA intergenic spacer showed that the Spanish strains nodulating V. sativa are phylogenetically close to those isolated from V. sativa and V. faba in different European, American and Asian countries forming a group related to Rhizobium leguminosarum. The analysis of the nodC gene of strains nodulating V. sativa and V. faba in different continents showed they belong to a phylogenetically compact group indicating that these legumes are restrictive hosts. The results of the nodC gene analysis allow the delineation of the biovar viciae showing a common phylogenetic origin of V. sativa and V. faba endosymbionts in several continents. Since these two legume species are indigenous from Europe, our results suggest a world distribution of strains from R. leguminosarum together with the V. sativa and V. faba seeds and a close coevolution among chromosome, symbiotic genes and legume host in this Rhizobium–Vicia symbiosis.