菜蚜茧蜂对萝卜蚜的控制作用研究

为了明确菜蚜茧蜂对萝卜蚜的控制作用,本文研究了在云南玉溪以6个不同蚜蜂比释放菜蚜茧蜂对萝卜蚜的寄生率,结果表明,按6个不同蚜蜂比释放菜蚜茧蜂寄生萝卜蚜后,其对萝卜蚜的寄生率随时间变化的曲线相似。放蜂后第3天,其对萝卜蚜的寄生率即达4%左右。前12 d寄生率虽有波动,但寄生率较低,多在5%以下,之后寄生率开始逐渐上升。蚜虫数量越多,其寄生率反而越高,21 d时,蚜蜂比250∶1和500∶1的寄生率已达26.06%和24.23%,显著高于其它蚜蜂比。蚜蜂比5∶1和25∶1时,萝卜蚜数量的增长最慢,21 d时,其数量仍呈直线上升趋势。蚜蜂比50∶1和150∶1时,萝卜蚜数量的增长开始呈直线上升趋势,到第18天趋于平稳。而蚜蜂比250∶1和500∶1时,萝卜蚜在第9天后,其种群数量呈爆发式增长,到第15天时即趋于平稳。萝卜蚜数量与有翅蚜数呈线性关系y=0.0097 x+10.953。僵蚜数与有翅蚜数呈指数函数模型,y=9.2582e0.0017 x。本研究表明菜蚜茧蜂对萝卜蚜有一定的控制作用,可以作为生物防治萝卜蚜的选择之一。     

异色瓢虫生物生态学研究进展

原产于亚洲的异色瓢虫[Harmonia axyridis Pallas(Coleoptera:Coccinellidae)]是最重要的捕食性瓢虫种类之一,被广泛应用于农林业害虫的生物防治.本文综合分析了国内外近几十年对异色瓢虫的研究成果,对其重要的生物学及生态学特性进行了归纳,主要涉及生活史、繁殖行为及策略、捕食行为和自残行为等,分析了相关研究对其应用前景的影响.基于异色瓢虫的人工饲养、农药交互作用以及入侵生态影响等的总结,提出了预防异色瓢虫造成生态不平衡的具体措施.     

Ten years of invasion: Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) in Britain

1. Harmonia axyridis was first recorded in Britain in 2004. Two subsequent earlier records were received from 2003. 2. The UK Ladybird Survey, a citizen science initiative involving online recording, was launched in 2005 to encourage people across Britain to track the spread of H. axyridis. Tens of thousands of people have provided records of H. axyridis and other species of ladybirds, creating an invaluable dataset for large‐scale and long‐term research. Declines in the distribution of seven (of eight assessed) native species of ladybird have been demonstrated, and correlated with the arrival of H. axyridis, using the records collated through the UK Ladybird Survey. 3. Experimental research and field surveys have also contributed to our understanding of the ecology of H. axyridis and particularly the process of invasion. Harmonia axyridis arrived in Britain through dispersal and introduction events from regions in which it was deliberately released as a biological control agent. The rapid spread of this species has been attributed to its high natural dispersal capability by means of both flight and anthropogenic transport. A number of factors have contributed to the successful establishment and indeed dominance of this polymorphic species within aphidophagous guilds, including high reproductive capacity, intra‐guild predation, eurytopic nature, high resistance to natural enemies within the invaded range, and potentially phenotypic plasticity. 4. The global invasion by H. axyridis and subsequent research on this species has contributed to the general understanding of biological invasions.     

Weak photoperiodic response facilitates the biological invasion of the harlequin ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

Photoperiodic regulation of reproductive diapause in two invasive and two native populations of Harmonia axyridis and in one native population of Harmonia yedoensis was investigated in laboratory at 20°C, five photoperiods (day length of 10, 12, 14, 16 and 18 h) and two diets: (i) eggs of the Angoumois grain moth Sitotroga cerealella and (ii) the green peach aphid, Myzus persicae. Laboratory strains originated from native populations of H. axyridis from Irkutsk province of Siberia and H. yedoensis from South Korea showed a strong photoperiodic response: under short photoperiods (10–14 h and 10–12 h for H. axyridis and H. yedoensis, correspondingly), all females which fed on eggs and most of those fed on aphids did not start to lay eggs during 40 days after emergence, while under long photoperiods, all females fed on aphids and most of those fed on eggs oviposited. The photoperiodic response of H. axyridis from South Korea was less strong: on the both diets, the range of the photoperiodic response (the difference in the proportion of ovipositing females between the treatments with long and short days) was ca 40%. In the European (Czech Republic) and in the Caucasian (Sochi region, Russia) invasive populations of H. axyridis, the photoperiodic response was very weak: the proportion of females that started oviposition (when fed on aphids) or at least reproductive maturation (when fed on eggs) during 40 days after emergence was close to 100%, independently of the photoperiodic conditions. Obviously, instead of a rapid micro‐evolutionary adaptation of the critical day length to a new climate, the invasive populations of the harlequin ladybird decrease their dependence on photoperiod and thus the weak photoperiodic response of SE Asian population of H. axyridis can be considered as a pre‐adaptation further developed during the invasion.     

Expansion of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) to European Russia and adjacent regions

An invasive alien species, the harlequin ladybird Harmonia axyridis (Pallas, 1773), has quickly expanded its distribution in Eastern Europe. Records of H. axyridis from 31 localities in Lithuania, Latvia, the Ukraine, European Russia, and the Northern Caucasus are summarized and mapped. Within the last few years this species has established in south Latvia, on the Baltic Sea shore (Kaliningrad oblast and Lithuania), in the western and central Ukraine, Crimea, and in the Northern Caucasus. Besides that, individual specimens have been found in 4 more localities in European Russia. The species is recorded from Lipetsk oblast (European Russia), Crimea, and Nikolaev oblast (the Ukraine) for the first time.     

Walking activity of flightless Harmonia axyridis (Coleoptera: Coccinellidae) as a biological control agent

The use of flightless strains of the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), established via artificial selection, can be highly effective as a biological control agent for aphids. However, flightless H. axyridis must depend on walking for dispersion. Therefore, data on the walking activity levels in flightless strains are important for the development of effective methods when releasing these agents in the field. Results of measurement of walking activity levels using an infrared actograph showed that walking activity levels during the daytime (but not nighttime) in both sexes of pure flightless strains tended to be lower than those of control strains. We also found that walking activity levels during the daytime for the F1 generation of hybrid strains, produced by reciprocal crossing between two pure flightless strains, were approximately equal to those of pure strains; the reduction in walking activity levels was not recovered by hybrid vigor. Our results indicate that the reduction in walking activity levels in the pure flightless strains was not caused merely by inbreeding depression stemming from the artificial selection process. Instead, potentially flight ability and walking activity levels in this species may be controlled by the pleiotropic effect of a gene.     

Role of long-chain hydrocarbons in the aggregation behaviour of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

The multicoloured Asian ladybirds, Harmonia axyridis (Pallas), form large aggregations inside dwellings to survive cold winters, causing annoyance to householders due to their abundance, allergenic properties and problems consequent on reflex bleeding. Flight to overwintering sites and macrosite choice of this species is well documented. H. axyridis shows a hypsotactic behaviour and a clear preference for contrasting visual elements. However, how the microsite is selected remains undocumented, although a better understanding of the factors implicated could lead to the development of new control methods for this pest. In this work, we hypothesised that non-volatile compounds are involved in the microsite choice and aggregation of this beetle. Long chain hydrocarbons were identified at aggregation sites, comprising saturated and unsaturated homologues. An aggregation bioassay was then conducted on overwintering individuals, highlighting the retention capacity of the identified compounds on the tested ladybirds. Additional investigations showed that H. axyridis males and females, originating from overwintering sites, deposit a similar blend of molecules while walking. A Y-shaped tube assay revealed that this blend is used by male and female congeners as cue allowing individuals to orientate towards the treated side of the olfactometer. These results suggest the use of two different blends of long chain hydrocarbons by H. axyridis during its aggregative period, the first one to lead conspecifics towards aggregation sites (microsites) and the second to ensure the cohesion of the aggregation. These findings support the potential use of these blends, in association with volatiles, in the design of traps in order to control infestations of this species in dwellings.     

Efficacy and nontarget effects of reduced-risk insecticides on Aphis glycines (Hemiptera: Aphididae) and its biological control agent Harmonia axyridis (Coleoptera: Coccinellidae)

The efficacy of three reduced-risk insecticides (pyrethrins, insecticidal soap, and narrow-range mineral oil) was determined for nymphs and adults of the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), an exotic pest of North American soybean, Glycine max (L.) Merr. These insecticides also were evaluated for nontarget effects on one of the aphid's key biological control agents, multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), including first and third instars, pupae, and adults. A Potter Spray Tower was used to conduct direct spray laboratory bioassays. Results indicated that although pyrethrins and narrow-range mineral oil caused 100% mortality to A. glycines nymphs and adults at 72 h posttreatment, insecticidal soap caused equivalent mortality to only the nymphs during the same time period. However, A. glycines adult mortality due to the insecticidal soap (83.3%) was significantly greater than the control. Pyrethrins were highly toxic to first instars of H. axyridis (98% mortality), but they had no effect on third instars, pupae, or adults. Mineral oil and insecticidal soap were moderately lethal to first (48.9 and 40% mortality, respectively) and third (31.9 and 38.8% mortality, respectively) instars of H. axyridis, but they had no effect on pupae and adults. Our results suggest that pyrethrins, insecticidal soap, and narrow-range mineral oil may prove useful for soybean aphid management in organic soybean due to efficacy against the aphid with differential nontarget effects on select stages of H. axyridis. Additional studies will be necessary to elucidate the efficacy of these insecticides under field conditions.     

Invasions by Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) in the Western Hemisphere: implications for South America

The multicolored Asian lady beetle, Harmonia axyridis (Pallas), native to Asia, has recently been detected in South America after successfully invading North America and Europe. This coccinellid is a voracious predator; therefore, it is popular and effective in biological control. Unfortunately, H. axyridis also has associated adverse impacts (i.e., as a household pest, pest of fruit production, and threat to non-target organisms). To predict the potential geographic extent of impacts of H. axyridis in South America we review the history of its invasion in the Western Hemisphere and address various factors critical to the future invasion (i.e., arrival, establishment, and spread) of new areas of South America. The likelihood of continued introductions (i.e., arrival) of H. axyridis to South America seems high, due to its popularity as a biological control agent and through accidental introductions. Establishment also seems likely in broad regions of South America. Climate matching with the native range suggested that much of southern South America may be suitable for establishment. In contrast, habitat matching with the native range suggested that northern South America may be more suitable. In addition, prey availability should not limit establishment of this predator. Once established, H. axyridis seems likely to spread by flight and human-assisted means. Overall, the invasion of H. axyridis over broad areas in South America seems likely.     

异色瓢虫成虫耐寒能力的季节性变化

为研究异色瓢虫Harmonia axyridis自然种群耐寒能力的季节性变化,测定了其过冷却点、体内含水量及总脂肪含量和低温存活力。结果表明：异色瓢虫成虫低温存活力呈现出明显的季节性变化,越冬前成虫的耐寒性显著强于夏季成虫和越冬后成虫。冷驯化（5℃, 5 d）可以显著提高夏季成虫的低温存活力。雌雄成虫过冷却点和体内含水量随气温的降低而降低,升高而升高。过冷却点7月份最高,分别为−7.6℃和−8.0℃;越冬中期（2008-01-15）最低,分别为−18.1℃ 和−16.9℃。雌雄成虫体内含水量9月份最高,分别为66.87%和68.01%,10月份显著降低,越冬后期（2008-02-19）最低,分别为52.94%和51.53%。越冬期间过冷却点和体内含水量显著低于其他时期。而雌雄成虫体内总脂肪含量在越冬开始就达到最高,分别为50.07%和47.93%,随后又逐渐降低,越冬期间显著高于其他时期。由此可知异色瓢虫自然种群的耐寒性呈现出明显的季节性变化,文中还就异色瓢虫自然种群耐寒性影响因素及其越冬策略进行了讨论。     

Locomotor Behavior of Flightless Harmonia axyridis Pallas (Col., Coccinellidae)

To improve the efficiency of the lady beetle H. axyridis as a biological control agent against aphids, a flightless population was obtained by feeding adults with a mutagen and selecting their progeny for nonflying but otherwise morphologically normal individuals. These flightless adults attempted to fly but immediately fell. They softened their fall by opening their elytrae and wings. The inability to fly could result from change in their flying behavior compared to control adults. The flight duration was very much shorter, and the wing beat frequency and, more particularly, the amplitude of the wing beats were clearly lower. More time was spent in the other components of the flight behavior such as wing rotation, wing immobility, and wing folding. The sequence of these patterns differed slightly, due mainly to change in their frequency. The locomotor behavior was not modified by the mutation, which affected only the wing muscles. Searching behavior of mutant adults differed from that of control adults only in that they took longer to encounter and ingest aphids. Nevertheless, the larval growth and reproductive rate remained unchanged. The behavioral and biological features of these flightless adults indicate that it should be possible to use them in biological control programs.     

Locomotory behavior of flightless Harmonia axyridis Pallas (Col., Coccinellidae)

To improve the efficiency of the ladybeetle Harmonia axyridis as a biological control agent against aphids, a flightless population was produced by feeding adults with a mutagen and selecting their progeny for non-flying but otherwise morphologically normal individuals. The inability to fly could result from a change in their flying behavior compared with control adults. Flight duration was very much shorter, wing beat frequency and more particularly the amplitude of the wing beats were clearly lower. More time was spent on the other components of flight behavior such as wing rotation, wing immobility and wing folding. The sequence of these patterns differed slightly mainly due to changes in their frequency. The locomotory behavior was not modified by the mutation, which only affected the wing muscles. The searching behavior of mutant adults differed from that of control adults only in that they took longer to encounter and ingest aphids. As this difference is not important, it should be possible to use this flightless population in biological control programs.     

Biological and biochemical characteristics for quality control of Harmonia axyridis (Pallas) (Coleoptera, Coccinellidae) reared on a liver-based diet

Biological and biochemical parameters of a flightless strain of Harmonia axyridis, fed on a pork liver-based artificial diet and on Ephestia kuehniella eggs as controls, were compared. The diet-grown larvae showed a significantly longer developmental time and a lower adult emergence rate compared to control larvae. The weights of the newly emerged adults were significantly higher for adults fed E. kuehniella eggs during their larval stages than fed the artificial diet. In contrast, larval food source had no effect on the duration of the pre-oviposition period or adult longevity. For adults fed on E. kuehniella eggs as larvae, a significantly longer pre-oviposition period, lower daily weight gain and fecundity were found for the diet-fed females compared to those fed on E. kuehniella eggs throughout the life span. The adult food source had no significant effect on longevity and fertility. Lower amino acid and fatty acid contents (in particular C16:1 and C18:3n-3) were found for the prepupae and newly emerged females obtained from diet-reared larvae compared to controls. Deficiencies in fatty acids C16:1 and C18:3n-3 were also observed in females obtained from E. kuehniella egg-reared larvae and fed on diet from adult emergence. The analyses of the foods showed deficiencies in artificial diet, especially for some amino and fatty acids. The results suggest a non-optimal composition of the artificial diet and some possibilities for its improvement. However, this polyphagous predator could be reared from first instar larvae to fully reproductive adults on a pork liver-based artificial diet.     

Effect of Low-Temperature Storage on Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae)

We evaluated the effects of constant low-temperature storage on Diaeretiella rapae (McIntosh) (Braconidae, Aphidiinae). Diaeretiella rapae mummies were stored at 5?±?1°C for 0–36 days. The percentage of D. rapae emergence varied (100-83%) after 0–32 days of storage. After 32 days, emergence reduced to 55%. According to our Probit analysis, 50% mortality (LT50) of the population of D. rapae was reached after 40 days of storage at 5°C. Storage for up to 32 days did not negatively affect emergence and survival. Cold exposure of D. rapae for 36 days did not influence morphological malformations, sex ratio, and emergence of the F1 generation. After 4–36 days of storage, D. rapae showed a gradual decrease in emergence, longevity, reproductive capacity, and F1 sex ratio. Diaeretiella rapae can be stored for up to 24 days at 5°C, at which time the percentage of parasitism and the F1 sex ratio remain above 38% and at 0.50, respectively.     

Influence of diet and photoperiod on development and reproduction of European populations of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

The current study examines the effect of photoperiod (16:08 or 12:12 h L:D) and diet (eggs of Ephestia kuehniella Zeller (Lepidoptera: Phycitidae) or the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae)) on the development and reproduction of the multicoloured Asian lady beetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). A long-term laboratory population of H. axyridis (since 1998) and a melanic and non-melanic population originating from field collected individuals of H. axyridis in Belgium were used in this study. Long day conditions (16 h photoperiod) shortened development of the field populations with 2–3 days when compared with short day conditions (12 h photoperiod). Oviposition in the field populations was delayed by 1–3 months when reared at a 12 h photoperiod. Dissections indicated that the females were in reproductive diapause. As compared with live pea aphids, a diet consisting of E. kuehniella eggs yielded heavier adult body weights (up to 12%) and increased the number of egg laying days (by 45–169%) for both field populations at a 16 h photoperiod and lengthened adult life span (by 45–92%) under both light regimens. The morph types differed in their response to the foods offered in terms of developmental rate, pre-oviposition period and number of oviposition days. The laboratory and field strains responded differentially to regimens of food and photoperiod. The study indicated a greater nutritional plasticity of the non-melanic morphs which may offer them a competitive advantage that may in part explain the predominance of non-melanic morphs in newly colonized areas.     

The potential impacts of the arrival of the harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in Britain

Abstract.  1. The harlequin ladybird, Harmonia axyridis , has recently arrived in Britain.
2. This species has been introduced from Asia into many parts of the world for biological control purposes.
3. In many parts of North America it has become the predominant aphidophagous coccinellid in less than 20 years, and in north-western Europe it is spreading and increasing in number rapidly.
4. Since establishment in North America and continental Europe, reports of its effectiveness as a biological control agent of aphids and coccids have been accompanied by accounts of negative effects on other aphidophagous species and humans.
5. Here the potential impacts of the arrival of the harlequin ladybird in Britain are assessed.     

Effect of alfalfa habitat change on dispersal behavior of Harmonia axyridis Pallas and Hippodamia variegata Goeze (Coleoptera: Coccinellidae)

An alfalfa grassland landscape was divided into 36 plots during 2014 season in Yuanzhou District of Guyuan city in Ningxia Hui Autonomous Region of P.R. China. In these three times repeated experiments, treatment of habitat fragmentation was divided into two grades: continuity (H = 0.0) and fragmentation (H = 1.0), and their habitat loss rate was divided into 6 grades: 90, 80, 70, 50, 20 and 0%. Considering habitat loss 0% of the plot as the reference, as a result of sweeping net and visual methods, results showed that the flight distance of the Harmonia axyridis was much higher than that of the Hippodamia variegata both in fragmentation and continuous habitats. In the alfalfa landscape, H. axyridis moved more by flying, while H. variegata moved more by crawling. There was a threshold effect that affected the movement behavior of lady beetles between 70 and 100% of the habitat loss. The population of the two species of lady beetles in the continuous habitat was higher than that in the habitat fragmentation and was more obvious in 70 and 50% plots of the habitat loss. The dispersal rate of the two species of lady beetles inside plots was higher than outside of the experimental plots, which reflected the low diffusivity of the ladybeetle. Habitat fragmentation affected the dispersal, migration and construction of two species of lady beetles on different spatial scales by disturbing the spread of natural enemies and searching for prey.     

The evolution of chemical defenses along invasion routes: Harmonia axyridis Pallas (Coccinellidae: Coleoptera) as a case study

The evolution of increased competitive ability (EICA) hypothesis (Blossey & Nötzold, 1995 ) postulates that escaping from coevolved enemies increases invaders fitness by energy reallocation from defenses and immunity to growth and reproduction. In this context, we evaluated the evidence of evolutionary change in invasive populations of Harmonia axyridis Pallas (Coccinellidae: Coleoptera). We measured egg defenses—cocktail of hydrocarbons on the egg's surface flagging egg toxicity and the concentration of the main alkaloid harmonine—in individuals from three populations along the invasion route (Japan: native, United States: introduced more than 30 years ago, South Africa: introduced in the early 2000s) in a common garden experiment. Our results support the EICA hypothesis: We found changes along the invasion route in the profiles of the hydrocarbons coating the eggs’ surface and a decrease in the concentration of harmonine in eggs from the most recent invasive South African population compared to the long established in the United States and the native Japanese ones.     

异色瓢虫成虫体型及体内脂肪含量对其耐寒能力的影响

为明确异色瓢虫Harmonia axyridis (Pallas)成虫体型及体内脂肪含量对其耐寒能力的影响, 本研究在2种发育温度(18℃和25℃)下通过表型可塑性诱导获得了不同体型的异色瓢虫成虫, 测定了成虫体型大小、体内脂肪含量、过冷却点(supercooling point, SCP)及其在恒定低温(constant low temperature, CLT)和变温(fluctuating thermal regime, FTR)下的存活率。结果表明: 较低发育温度(18℃)下的成虫体型比25℃下的明显大(P<0.01), 体内脂肪含量显著高于25℃下的(P<0.01); 且两2种发育温度下成虫体内脂肪含量与虫体干重呈较好的正相关关系。由SCP频次分布图可知, 饲养在18℃下的成虫SCP主要集中在-8 ~ -6℃范围内, 饲养在25℃下的成虫SCP主要集中在-10 ~ -9℃范围内; 且成虫体型大小与过冷却能力呈现负相关关系。经过相同时间低温暴露后成虫的存活率按下列顺序降低: FTR18℃＞FTR25℃＞CLT18℃＞CLT25℃。结果表明低温暴露过程中脂肪贮存对异色瓢虫成虫存活是非常重要的, 但是冷伤害是影响存活的基本因素。