布氏潜蝇茧蜂对橘小实蝇幼虫寄生作用的研究

在试验室条件下研究了布氏潜蝇茧蜂Fopius vandenboschi(Fullaway)的寄生习性。结果表明:该寄生蜂嗜好寄生低龄的橘小实蝇幼虫;橘小实蝇幼虫的密度对布氏潜蝇茧蜂的寄生有明显的影响;被寄生的幼虫数随寄主自身密度的增加而增加,当寄主幼虫密度达每果片30只以上时,寄生数量的增加幅度就趋于下降,用Holling圆盘方程模拟为Na=0.9051N/(1 0.0163N)。此外,布氏潜蝇茧蜂的自身密度对寄生作用也有影响,随着寄生蜂数量的增加,寄生蜂的发现域逐渐变小,用Hassell-Varley方程表示为α=0.4655P-0.5807。     

Egg–larval opiine parasitoids (Hym., Braconidae) of tephritid fruit fly pests do not attack the flowerhead-feeder Trupanea dubautiae (Dipt., Tephritidae)

Abstract:  We investigated the potential impact of three opiine tephritid fruit fly parasitoids: Fopius arisanus (Sonan), Fopius caudatus (Szépligeti) and Fopius ceratitivorus Wharton, on the non-target native Hawaiian tephritid, Trupanea dubautiae (Bryan), infesting flowerheads of the endemic Asteraceae shrub Dubautia raillardioides Hillebrand. The three species are the only known opiine fruit fly parasitoids that attack host eggs (but occasionally attack first instars). F. arisanus , which originated in southeast Asia, is now widely established in Hawaii and elsewhere in the world, while the other two are African species currently in quarantine in Hawaii. In the laboratory, field-collected flowerheads of D. raillardioides containing T. dubautiae eggs and first instar larvae were exposed to naïve female wasps of each of the three Fopius species in the absence (no-choice test) or presence (choice test) of papaya fruit infested with eggs of the Mediterranean fruit fly Ceratitis capitata (Wiedemann), the parasitoids' normal host. All three Fopius species visited the papaya fruit much more often than the flowerheads, and displayed normal ovipositional responses (probing and stinging) on the fruit in the choice test. None of the three parasitoid species showed ovipositional responses to flowerheads in either choice or no-choice tests. As a result, not a single T. dubautiae egg or larva was attacked by any of the three parasitoids, indicating that these parasitoids of pest tephritids are unable to recognize the microhabitats of flowerhead-feeding tephritids. The results suggest minimal risk of non-target impact in these biological control agents.     

阿里山潜蝇茧蜂对橘小实蝇卵的寄生效能

在温度25℃、相对湿度75%、光周期L∶D=12∶12的条件下,研究了阿里山潜蝇茧蜂对橘小实蝇卵的寄生效能。结果表明:橘小实蝇卵的密度变化对阿里山潜蝇茧蜂的寄生作用有很大影响,可用功能反应模型HollingⅡ型模拟,其模拟方程为Na=0.9082N0/(1 0.0046N0);阿里山潜蝇茧蜂成虫的自身密度对寄生作用也有较大影响,可用Hassell-Varley模型模拟,其模拟方程为α=0.2858P-0.3448。     

Swarming, Delayed Sexual Maturation of Males, and Mating Behavior of Fopius arisanus (Sonan) (Hymenoptera: Braconidae)

Fopius arisanus is unusual among hymenopterous parasitoids in males having an obligatory premating period. We confirmed Hagen's (1953) view that sperm takes several days to migrate from the testes to the seminal vesicles. Males mated for the first time only 4 days after emergence, the time that sperm was first ever recorded in the seminal vesicles. In the field, we studied the sexual maturation of F. arisanus males in relation to their behavior. In general, sexually immature males were found in male-only swarms that persisted over several days in host tree canopies. Mature males were usually found in loose aggregations in the vegetation beneath host trees. Females entered these loose aggregations and were mated, whereas they were generally absent from swarms in the canopy. Swarming is therefore apparently not a primary component of the sexual communication system of the species. We describe, for the first time in F. arisanus, the behavioral sequence that accompanies the intersexual communication that leads to mating. Males probably release a volatile chemical that attracts females from a distance, but we have only circumstantial evidence for this. We also postulate that males may form aggregations to amplify the effects of this distance attractant. In the vicinity of males, females release a pheromone that attracts males, a process we demonstrated with female-baited sticky traps.     

Mass-rearing biology of Fopius vandenboschi (Hym., Braconidae)

Abstract:   Basic biological information concerning the reproductive activities of Fopius ( Biosteres ) vandenboschi (Fullaway) (Hym., Braconidae, Opiinae) were determined to facilitate insectary mass production. Mean (±SE) progeny production per generation (yield) of 200 ♀♀ F. vandenboschi was 6835.8 ± 433.2 and 3755.8 ± 112.4 parasitoids, with 24-h exposure to second instar Bactrocera dorsalis (Hendel), and Ceratitis capitata (Wiedemann), respectively. Ceratitis capitata as a factitious host was more sensitive to parasitism, producing a significantly higher percentage of uneclosed host puparia frequently containing parasitoid cadavers (22.5 ± 0.8%), than B. dorsalis (3.4 ± 0.2%). The overall mean production of female offspring was ≥50%♀♀ in both host species. Unlike several other opiine parasitoids, young (5-day-old) females of F. vandenboschi produced low proportion of daughters (26–37%♀♀) and significantly shifted production to female-biased offspring (53–71%♀♀) at older age intervals (16–30 days). Based on the parasitoid yield data with a 24-h exposure period to second instar host larvae of B. dorsalis , about 150 cage replicates (of 200 ♀♀ each) may be sufficient to mass produce about 1 million parasitoids of F. vandenboschi during the reproductive period of 5–30 days, with an average of 56% female offspring. A short oviposition exposure period of 6 h was not optimal for mass production of F. vandenboschi . Total yield at 6 h exposure was one-fifth the production at 24-h exposure, using B. dorsalis hosts.     

Competitive Superiority of Early Acting Species: A Case Study of Opiine Fruit Fly Parasitoids

Koinobiont parasitoids that attack an early host stage may have an advantage in suppressing competing parasitoids that attack later stages of the same host. We examined the competitive interaction between the two most important parasitoids of tephritid fruit flies in Hawaii, Fopius arisanus (Sonan), and Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae). The former species attacks host eggs while the latter attacks host larvae, and both species emerge as adults from the host puparia. F. arisanus physiologically suppressed egg development of D. longicaudata. Over 90% of D. longicaudata eggs died in the presence of F. arisanus larvae within host larvae of either the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) or the oriental fruit fly, Bactrocera dorsalis (Hendel). D. longicaudata appeared not to discriminate against hosts previously parasitized by F. arisanus. The mechanism that F. arisanus uses to eliminate D. longicaudata is similar to that which it employs to eliminate five other larval fruit fly parasitoids so far reported in Hawaii. This suggests that there is a broad competitive superiority of the early acting species in fruit fly parasitoids. We discuss the implication of this in relation to future biological control introductions against tephritid fruit flies.     

Effect of temperature on immature development and longevity of two introduced opiine parasitoids on Bactrocera invadens

Temperature‐dependent development, parasitism and longevity of the braconid parasitoids, Fopius arisanus Sonan and Diachasmimorpha longicaudata Ashmed on Bactorcera invadens Drew Tsuruta & White, was evaluated across five constant temperatures (15, 20, 25, 30 and 35°C). Developmental rate decreased linearly with increasing temperature for both the parasitoid species. Linear and Brière‐2 nonlinear models were used to determine the lower temperature threshold at which the developmental rate (1/D) approached zero. For F. arisanus, lower thresholds to complete development estimated with the linear and nonlinear models were 10.1 and 6.9°C, respectively. The total degree‐days (DD) required to complete the development estimated by the linear model for F. arisanus was 360. In D. longicaudata, the linear and nonlinear models estimated lower thresholds of 10.4 and 7.3°C, respectively, and the total DD estimated was 282. In F. arisanus, percentage parasitism differed significantly across all temperatures tested and was highest at 25°C (71.1 ± 2.5) and lowest at 15°C (46.4 ± 1.4). Parasitoid progeny sex ratio was female biased at all temperatures except at 20°C. In D. longicaudata, percentage parasitism was highest at 20°C (52.2 ± 4.0) and lowest at 15°C (27.7 ± 2.5). Parasitoid progeny sex ratio was female biased and similar for all temperatures. Adult longevity of both parasitoids was shortest at 35°C and longest at 15°C, and females lived significantly longer than males at all temperatures tested. Our findings provide some guidance for future mass rearing and field releases of the two parasitoids for the management of B. invadens in Africa.     

应用寄生蜂和不育雄虫防控田间橘小实蝇

食品安全已成为当今社会广受关注的问题。尽管国内的一些学者就阿里山潜蝇茧蜂[Fopius arisanus(Sonan)]和橘小实蝇SIT技术分别开展了不同程度的研究,然而关于应用该蜂和不育雄虫对橘小实蝇[Bactrocera dorsalis(Hendel)]进行田间联合防治的研究还未见相关报道。为此,为探讨天敌昆虫和雄性不育技术对橘小实蝇的田间综合治理(IPM)技术,开展了阿里山潜蝇茧蜂和橘小实蝇不育雄虫的田间释放试验:首先应用性引诱剂降低田间野生雄虫数量;而后,释放橘小实蝇不育雄虫,进一步降低田间橘小实蝇种群数量;最后,释放阿里山潜蝇茧蜂对田间残余的橘小实蝇卵进行追踪寄生,以达到持续控制的目的。通过监测整个防控期田间橘小实蝇的种群数量以及果实受害率和防治效果作为评价指标评价该防治方法的综合防治效果。结果表明:应用阿里山潜蝇茧蜂、橘小实蝇不育雄虫并配合引诱剂的综合措施对橘小实蝇的种群数量有明显控制作用,田间总体防治效果可达90%左右。此外,提出完善橘小实蝇田间防控措施的建议,并提出该研究的不足以及有待进一步开展研究的方向。     

Attraction and feeding responses of Mediterranean fruit fly and a natural enemy to protein baits laced with two novel toxins,phloxine B and spinosada

Studies were conducted to determine attraction and feeding propensity of Mediterranean fruit fly, Ceratitis capitata (Wiedemann), to different protein bait mixtures with and without the insecticides malathion, spinosad, and phloxine B. Protein baits were more attractive to females than to males. Protein-starved females responded more than protein-fed females. The type of protein (USB^® yeast hydrolysate enzymatic, Mazoferm^®E802, Nu-Lure^®Insect Bait, or Provesta^® 621 autolyzed yeast extract) in the bait had a major influence on C. capitata attraction, which was strongest to fresh Provesta. Aged baits (four day-old) were not as attractive as fresh baits. In feeding propensity studies, highest response was observed for USB protein. On the basis of attraction and feeding responses Provesta (attraction and feeding) and USB (feeding) outperformed the standard Nu-Lure. Protein-starved flies were much more likely to feed on protein compared to protein-fed flies. For protein-starved flies, a mixture of Provesta and malathion repelled fruit flies, compared to a mixture of Provesta and spinosad or phloxine B. This was not the case with protein–fed flies. The wasp Fopius arisanus (Sonan), one of C. capitata's primary natural enemies in Hawaii, would not consume protein baits. Our studies suggest that spinosad or phloxine B, with low contact toxicity, mixed with protein baits offers a more environmentally friendly choice for control of C. capitata and conservation of F. arisanus, whereby the nontarget effects of broad spectrum contact poisons such as malathion can be avoided. Presumably, due to greater selectivity with spinosad and phloxine B bait treatments, the host would be killed, but not the natural enemy.     

阿里山潜蝇茧蜂Fopius arisanus的发育起点温度和有效积温

对橘小实蝇卵寄生蜂阿里山潜蝇茧蜂Fopius arisanus(Sonan)的发育起点温度和有效积温进行了研究。结果表明,阿里山潜蝇茧蜂的卵、幼虫、蛹、雌成虫、雄成虫和世代的发育起点温度分别为9.7、8.8、8.5、8.7、8.7和9.3℃;有效积温分别为25.2.200.2、133.6、344.4、242.8和440.2日度。在19-31℃之间,阿里山潜蝇茧蜂的发育历期随温度的升高而缩短。