Nutritional value of brine shrimp cysts as a factitious food for Orius laevigatus (Heteroptera: Anthocoridae)

Decapsulated cysts of the brine shrimp Artemia franciscana were assessed as a factitious food for rearing the anthocorid predator Orius laevigatus. Developmental and reproductive traits of O. laevigatus reared for a single generation on A. franciscana from three geographical locations or on gamma-irradiated eggs of the Mediterranean flour moth Ephestia kuehniella were compared. There was no effect of diet on nymphal survival but nymphal period on E. kuehniella eggs (12.2 days) was 0.7-1.6 days shorter than on the Artemia diets. The predator developed 0.5-1 day faster on cysts from San Francisco Bay (USA) than on cysts from Great Salt Lake (USA) or Macau (Brazil). Fecundity on brine shrimp cysts from different locations was similar to that on flour moth eggs (142-187 eggs/female). The biochemical composition of decapsulated cysts from San Francisco Bay was compared with that of E. kuehniella eggs. Depending on the type of analysis, Artemia cysts contained higher or similar amounts of protein as compared with E. kuehniella eggs, but amino acid patterns were generally similar. Flour moth eggs were almost three times richer in fatty acids than brine shrimp cysts, with some marked differences in fatty acid profiles. Because nutrient imbalances in a diet may be expressed only after several generations of rearing, the predator was cultured for three consecutive generations on A. franciscana cysts from San Francisco Bay. In the third generation on brine shrimp cysts, nymphs took 18% longer to develop, and adults were shorted-lived and about 60% less fecund than those maintained on E. kuehniella eggs. Brine shrimp cysts may be used as a supplement in the mass production of O. laevigatus but may not be a suitable food for long-term culturing of the predator.     

Influence of thrips prey species on the life-history and behaviour of Orius albidipennis

The effects of two diets, i.e., cowpea leaves plus Megalurothrips sjostedti larvae versus cowpea leaves alone, on nymphal development and mortality of Orius albidipennis were studied under controlled laboratory conditions in Benin, West Africa. Nymphal development was longer when O. albidipennis was fed with cowpea leaves only, compared to the diet complemented with M. sjostedti larvae (17.6 days versus 14.8, respectively). Nymphal mortality was very high (78.6%) if fed with cowpea leaves only, and still relatively high if the diet was complemented with thrips larvae (44.4%).In a separate study on the longevity and fecundity of O. albidipennis adult females feeding on M. sjostedtilarvae, an average of 6.8 eggs per day (maximum 16 eggs) and a mean total fecundity of 61.1 eggs were observed. The females lived on average 13.5 days.Finally, observations on the predation by O. albidipennis adults on three different thrips species revealed that M. sjostedti larvae were killed at a lower rate than larvae of Ceratothripoides cameroni and Frankliniella schultzei. Higher predation rates were measured using unmated females and males than in mated females. However, the rate of first attack, measured as first larva attacked in dual-choice assays, was higher for M. sjostedti when a F. schultzei larva was offered simultaneously, and not different when a C. cameroni or Sericothrips adolfifridericilarva was offered.The results of this study are discussed with regard to the lack of efficacy of O. albidipennis as biological control agent for M. sjostedti.     

南方小花蝽对寄主植物的产卵选择性及其卵的保存条件

室内研究南方小花蝽Orius similis Zheng在9种产卵寄主植物(辣椒,豇豆,长寿花,迎春花,黄荆,绿豆芽,棉花,石莲花,太阳花)的嫩茎上的产卵量、孵化率及繁殖系数。结果表明,南方小花蝽对不同产卵植物具有显著的选择差异性。从产卵量看,对辣椒嫩枝选择性最强,其产卵量占总产卵量的23.4%;从孵化率看,产在迎春花嫩茎上的卵的孵化率最高;从繁殖系数看,辣椒嫩枝和迎春花嫩茎作为产卵植物的繁殖系数较高,分别为7.6和12.8;从辣椒嫩枝和迎春嫩茎上的繁殖系数的构成看,两者明显属于2种不同的类型,前者属于高着卵量、低存活率类型,后者属于低着卵量、高存活率类型。对南方小花蝽不同虫态进行了抗寒能力的测定,结果表明南方小花蝽卵的抗寒能力最强,成虫次之,1~2龄若虫最弱。在此基础上做了卵的低温保藏实验,结果表明要保证80%以上的孵化率,最佳保藏条件为8℃下保藏9天。     

Liver-based artificial diets for the production of Orius laevigatus

Different meat- and liver-based artificialdiets were designed for the generalist predatorOrius laevigatus (Fieber) (Anthocoridae)and their suitability was compared to that ofits factitious food, Ephestia kuehniellaZeller (Pyralidae) eggs. The quality of thefood was measured by its ability to promotegrowth and oviposition of the insect. Nymphaldevelopment was slower on artificial diets thanon the control food, taking 15.0–15.9 days vs.14.3 days, respectively. Survival of nymphs fedartificial diets varied from 68.0–92.5%,compared with 96% for those fed E. kuehniella eggs. Adult weights were, however,not affected by diet. Fecundity of femalesprovided with liver diets was similar to orsomewhat lower than that of females fed Ephestia eggs. Oviposition rate and egg hatchwere similar on all diets tested. The resultssuggest that beef liver was the most importantcomponent of the diets tested, offering theessential nutrients to sustain growth andreproduction of O. laevigatus.Supplementing ingredients, like ground beef,egg yolk, sucrose and vitamin C can improve thenutritional value of the diet for O.laevigatus, but effects are rather small.Artificial diets containing liver and egg yolkas the main components may prove useful to makemass production of O. laevigatus andother heteropteran predators more cost effective.     

南方小花蝽在不同空间及笼罩条件下对西花蓟马的控制作用

利用小花蝽控制外来害虫西花蓟马越来越受到人们的重视。本文在室内研究了5种空间异质条件下南方小花蝽对西花蓟马的捕食作用,并研究了笼罩条件下4种比例释放南方小花蝽对西花蓟马的控制效果。结果表明,不同空间异质下,南方小花蝽对西花蓟马的功能反应均符合Holling Ⅱ圆盘方程;以瞬时攻击率和寻找效应为评价指标,发现南方小花蝽在小容器中的瞬时攻击率（a'）最高,为0.9204,寻找效应最好;在大容器且空间异质最复杂的处理中的瞬时攻击率（a'）最低,为0.6303,寻找效应最差。在笼罩条件下,以3:120和6:120比例释放南方小花蝽和西花蓟马,其控制效果差;以9:120的比例释放,5周后对西花蓟马成虫和若虫的控制效果分别达到74.70％和81.01％;以15:120比例释放,5周后对西花蓟马成虫和若虫的控制效果分别达到95.71％和89.02％。结果显示空间越小或异质性越简单,越利于南方小花蝽捕食西花蓟马。若实际生产中采用9:120的益害比例释放南方小花蝽,既可以达到对西花蓟马较好的控制效果,又相对节约成本。     

不同猎物饲喂对南方小花蝽捕食量和喜好性的影响

为探讨南方小花蝽对不同猎物的捕食喜好性,室内用西花蓟马、蚕豆蚜、二斑叶螨、混合饲料(同时饲喂3种猎物)分别饲喂南方小花蝽驯化两代,研究了4种饲喂处理的南方小花蝽初孵若虫、5龄若虫和雌成虫对西花蓟马、蚕豆蚜和二斑叶螨的捕食量和喜好性。结果显示不同猎物饲喂处理驯化的南方小花蝽1龄若虫对同一种猎物的捕食量和喜好性均不存在显著差异。南方小花蝽5龄若虫和雌成虫对某种猎物的捕食量因前期取食的猎物种类不同而有显著差异。南方小花蝽5龄若虫和雌成虫均表现出对西花蓟马2龄若虫的正喜好性。蚕豆蚜饲喂处理的5龄若虫和雌成虫对蚕豆蚜表现出正喜好性,除二斑叶螨饲喂处理外其余3种处理的南方小花蝽5龄若虫和雌成虫均表现出对二斑叶螨的负喜好性。以上结果表明4种饲喂驯化处理的南方小花蝽1龄若虫的喜好性不受前期取食猎物的影响,但5龄若虫和雌成虫对前期取食过的猎物的喜好性增强,存在一定的学习行为。     

Continuous rearing of the predatory anthocorid Orius laevigatus without plant materials

The omnivorous anthocorid predator Orius laevigatus is an economically important biological control agent of several small arthropod pests including the western flower thrips Frankliniella occidentalis. Mass rearing systems for Orius bugs typically make use of plant materials such as bean pods as an oviposition substrate and moisture source. Omission of plant materials from the mass rearing system of these beneficial arthropods could drastically improve the cost‐effectiveness of their production and thus stimulate their use in augmentative biological control. This study investigated the effect of a plantless rearing system, using wax paper as a walking substrate, water encapsulated in Parafilm domes, and an artificial oviposition substrate made of Parafilm and moist cotton wool, on the developmental and reproductive fitness of O. laevigatus. Plantless rearing during four generations resulted in females with an 11% lower body weight and a pre‐oviposition period that was prolonged by 29%. However, other biological parameters were not negatively affected by the absence of plants. In addition, plantless‐reared females had similar predation rates on F. occidentalis larvae as their peers maintained on plants. Our study indicates that the omission of plant material from the production cycle of O. laevigatus is possible when Ephestia kuehniella eggs are provided as a nutritionally optimal food source.     

Seasonal abundance of hemipteran predators in relation to western flower thrips Frankliniella occidentalis (Thysanoptera: Thripidae) on weeds in the eastern Mediterranean region of Turkey

Generalist predators and the prey species Frankliniella occidentalis (Pergande) were periodically sampled from 64 weed species to determine their numerical interrelationships in three ecologically different locations in the eastern Mediterranean region of Turkey in 2002–2003. Adult and nymph stages of seven hemipteran predator species were recorded: Deraeocoris pallens Reuter, Geocoris arenarius (Jakovkev), Nabis punctatus Costa, Orius laevigatus Fieber, Orius majusculus (Reuter), Orius niger (Wolff) and Piocoris erythrocephalus (Peletie and Serville). The most common and abundant predator species was O. niger, which was found on 53 weed species in the winter–spring and summer–fall periods; the highest total numbers of O. niger adults per weed species were 139, 275, 266 and 325 on Urtica urens, Sinapis arvensis, Lamium amplexicaule and Mentha aquatica, respectively. Relatively higher numbers of Orius spp. nymphs were detected on the weed species Echium plantagineum, Cichorium intybus, Heliotropium europeum, Mentha aquatica and Polygonum aviculare. Orius spp. were attracted to flowers in significantly higher numbers than to leaves of the investigated weeds. No significant correlation was found between the numbers of Orius spp. and F. occidentalis on the major weed species, except E. plantagineum. These findings suggest that weeds may provide Orius spp. with resources other than prey, such as nectar and pollen, shelter, and breeding sites. The weed species on which relatively higher numbers of Orius adults and nymphs were found may be considered as candidates for studies aiming to include weeds to enhance integrated pest management of F. occidentalis on crops.     

Phenology of the Predatory Bugs Orius vicinus (Heteroptera: Anthocoridae) and Sejanus albisignata (Heteroptera: Miridae) in Otago, New Zealand, Apple Orchards

The phenology of the anthocorid, Orius vicinus and the mirid, Sejanus albisignata , was studied in apple orchards in Otago, New Zealand, from 1995 to 1998. The bugs were sampled on shoot and fruit clusters, and with beating trays and passive sticky traps. Three age classes of each bug were identified in the cluster and tray sampling, while the traps caught only adults. Both cluster and beating tray sampling successfully identified the generations. O. vicinus completed two generations per year with peak numbers of adults of each generation occurring in January and February/March, respectively. A very small partial third generation occurred in the warmest season. Adult females from the second generation overwintered. S. albisignata completed two full generations and a partial third generation each season. Peak adult numbers of each generation occurred, respectively, in December/January, February/March and April/May. S. albisignata overwinters in the egg stage but the proportions of these eggs from the three generations are not known. Both O. vicinus and S. albsignata are polyphagous and a range of their known prey species coexist with them on the apple trees in spring and summer.     

军配盲蝽和南方小花蝽对茶网蝽若虫的捕食作用

茶网蝽Stephanitis chinensis是一种为害春茶的重要害虫,本文研究了天敌军配盲蝽Stethoconus japonicus和南方小花蝽Orius similis对茶网蝽的捕食能力,为茶网蝽的生物防治提供科学依据。在室内开展军配盲蝽和南方小花蝽对茶网蝽3龄若虫的捕食功能反应和寻找效应以及南方小花蝽的种内干扰反应研究。结果表明军配盲蝽和南方小花蝽对茶网蝽3龄若虫的捕食功能反应均符合Holling Ⅱ型。军配盲蝽和南方小花蝽的捕食量与茶网蝽3龄若虫的密度呈正相关,但寻找效应与猎物密度呈负相关。南方小花蝽成虫、3龄若虫对茶网蝽3龄若虫的日最大捕食量（11.49头、12.82头）大于军配盲蝽成虫、3龄若虫（10.10头、6.41头）;军配盲蝽成虫对茶网蝽的寻找效应高于其3龄若虫,而南方小花蝽3龄若虫的寻找效应高于成虫。南方小花蝽成虫、3龄若虫对茶网蝽3龄若虫的捕食作用均存在种内干扰反应,且符合Hassell模型,分别为E=0.4263P^-0.825和E=0.5234P^-0.762。综上研究结果,军配盲蝽和南方小花蝽对茶网蝽3龄若虫的捕食作用较强,均具有良好的生物防治潜能。