Host-independent artificial rearing of Eucryptorrhynchus brandti (Coleoptera: curculionidae)†

Eucryptorrhynchus brandti (Harold) is a trunk boring pest of Ailanthus altissima in China and is a potential biological control agent for invasive A. altissima in the USA. In this study, we developed a host-independent artificial rearing method for E. brandti adults and larvae, including fresh thin slices of potato for adults and a potato-based diet (referred to as diet 6) for larvae. Adults reared on thin slices of potato oviposited normally and larvae reared on diet 6 exhibited successful pupation and eclosion and short developmental duration. The rates of larval survival, pupation, and adult emergence were 63.3?±?0.26, 86.7?±?0.42, and 93.5?±?0.33%, respectively. This method could be used for the mass rearing of E. brandti.     

Rearing of the fruit fly parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae) on X-ray irradiated larvae of Ceratitis capitata (Diptera: Tephritidae)

We evaluated the effects of X-ray irradiation on larvae of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), with the aim of finding a treatment that prevented adult fly emergence, yet did not adversely affect larval quality as rearing hosts for the parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Ichneumonidae). Two experiments were carried out. In the first experiment, small numbers of larvae were held in Petri dishes with and without small amounts of rearing media and then irradiated with doses of X-rays ranging from 0 to 8333.6 R (equivalent to 80 Gy). In the second experiment, higher numbers of larvae were held in a manner resembling mass-rearing conditions, and were then irradiated with X-rays ranging from 0 to 10,417 R (equivalent to 100 Gy). In both experiments, the only factor that significantly affected fly emergence was irradiation of larvae. Fly emergence decreased markedly as the irradiation dose increased, and complete suppression of fly emergence was achieved at 6250.2 R (equivalent to 60 Gy) when larvae were irradiated in small batches with or without rearing media. Irradiation also affected the fertility of those flies that did emerge following treatment. In the second experiment, we found the parasitoids reared from irradiated larvae produced a higher parasitism rate and a higher number of female offspring than did parasitoids reared from control (non-irradiated) larvae. Mean fecundity of F1 parasitoids reared from irradiated larvae were affected positively by irradiation only at the 8333.6 R (80 Gy) dose. Our results show that X-ray irradiation can be used to inhibit fruit fly adult emergence and that irradiated larvae are at least as good a rearing substrate as non-irradiated larvae. Future studies should focus on the adjustment of our findings to a mass-rearing scale.     

A plastic container for rearing insects on artificial diets

Abstract

Entomology Division’s Insect Rearing Section, in Auckland, has developed an insect rearing container especially suited to use with artificial diets (Fig. 1).     

In vitro rearing ofLysiphlebus fabarum [Hym.: Braconidae]

In vitro rearing of the aphid endoparasitoidLysiphlebus fabarum (Marshall) (Hymenoptera, Braconidae) was attempted. Successful permanent cultures ofAphis fabae Sc. andMyzus persicae Sulz. cells were not obtained. Therefore, parasitoid larvae were reared in 2 unnatural media rone of which included cells ofCeratitis capitata Wied. (Diptera, Trypetidae). A group of larvae was reared in a substrate to which parasitoid teratocytes had been added. SinceLysiphlebus fabarum females did not oviposit into paraffin droplets including the substrates, the larvae were directly transferred from parasitized aphids into the rearing media. Several larvae reached the final instar, but only 2 out of the 48 tested in the 3 substrates became adults. The meaning of teratocytes inin vitro rearing of Aphidiine, Braconids is discussed. This work was supported by a grant from the italian Ministry of Education (M.P.I. 40%).     

Laboratory studies on the larval food habits of the ground beetle Amara (Curtonotus) gigantea (Motschulsky) (Coleoptera: Carabidae: Zabrini)

Ground beetles (Coleoptera: Carabidae) are important components of soil ecosystems in temperate zones, but our knowledge regarding the ecology of many species is limited. This study examined larval food habits in the ground beetle Amara (Curtonotus) gigantea (Motschulsky) using laboratory‐rearing experiments. Because this beetle is a member of the tribe Zabrini, which includes several species that exhibit granivory during larval and/or adult stages, three diet types were tested, with starvation as a control: Tenebrio larvae, mixed seeds (Bidens pilosa (Asteraceae), Setaria spp., Digitaria ciliaris (both Poaceae), and Humulus scandens (Moraceae)), and Tenebrio larvae + mixed seeds. Because of high larval mortality during overwintering under laboratory‐rearing conditions, survival and the duration of development through pre‐overwintering stages (first and second instars) were compared. Larvae fed the diet of Tenebrio larvae + mixed seeds showed the highest survival (89%), followed by the diet of Tenebrio larvae (83%), but the difference between the two treatments was not significant; similarly, developmental durations did not differ between these two diets. Larvae fed the mixed‐seeds diet showed markedly lower survival, and no larvae reached the second instar. Therefore, for A. gigantea larvae, animal food results in high larval performance, whereas seeds provide a low value diet; animal food is essential for larval development, but seeds provide no benefit, even as a dietary supplement. Overall, the present results suggest that A. gigantea larvae are omnivorous but with a mainly carnivorous food habit.     

New larval agar-based diet for laboratory rearing of Mediterranean fruit fly <Emphasis Type="Italic">Ceratitis capitata</Emphasis> (Diptera,Tephritidae)

Five larval diets for laboratory rearing of Ceratitis capitata were tested. These diets were based on wheat bran, microcellulose, potato starch and agar. To evaluate the quality of diet, pupal rearing efficacy and pupal weight were checked. The best results were obtained with an agar based diet used for Manduca sexta laboratory rearing. To simplify the preparation and to reduce the cost of this diet, a new formulation was developed. Larvae reared on the new agar-based diet achieved higher pupal rearing efficacy than larvae reared on bran diet recently used in medfly mass rearing facilities. Heat treated medflies reared on the new agar-based diet achieved similar pupal rearing efficacy with heat treated medflies reared on bran diet. When testing population density, higher pupal rearing efficacy was again achieved on new diet. The highest pupal rearing efficacy was achieved with 100 eggs per 25 g of diet, lowest with 500 eggs per 25 g of diet. Concerning pupal weight, there was no difference in results achieved on Petri dishes with different larval population densities. Larvae reared on new agar-based diet reached better results than larvae reared on bran diet. The preparation of the new diet is simple and the cost is low, so it is good for laboratory tests and rearing.     

Influence of larval rearing diet on the intensive searching behaviour ofHarmonia axyridis [Col.: Coccinellidae] Larvae

The capture of prey by last instar larvae of the aphidophagous coccinellidHarmonia axyridis Pallas (Col.,Coccinellidae) modified larval movement so that extensive search was replaced by intensive search. The continuous rearing of this species on eggs ofEphestia kühniella Zell. (Lep.,Pyralidae) or on the aphidAcyrthosiphon pisum Harris (Homopt.,Aphidae) led to conditioning. Only larvae that ate the same prey as they were reared on, adopted intensive searching movements after feeding. Using larvae reared on substitute prey in biological control systems may decrease the efficiency of the released predators.     

Larval growth and development in the caddisfly Cheumatopsyche brevilineata under natural thermal regimes

Cheumatopsyche brevilineata (Iwata) is a filter‐feeding caddisfly without distinct or distinguishable cohorts. In a semi‐natural channel, we reared fourth and fifth instar larvae of C. brevilineata in individual cages with hourly recording of water temperature. We calculated the individual growth rate from the wet‐weight gain of each larva, and the development rate from the ratio of larvae that progressed to the next instar or pupal stage during each rearing experiment. We analyzed the linear regressions of growth (increase in size) and development (physiological and morphological progression toward maturity) rates against the statistical parameters of water temperatures during each rearing period, i.e. mean and given percentiles of water temperatures. We presumed that the most appropriate parameter of water temperature to explain larval growth and development would show a peak value of the determination coefficients (r²) in the linear regressions. There were highly significant regressions in the growth rates for fourth and fifth instar larvae and in development rates for fourth instar larvae against every statistical parameter of water temperature, but not in the development rates for fifth instar larvae. For the growth of fourth and fifth instar larvae, we could not specify the most appropriate parameters of water temperatures, because we observed no clear peaks in the determination coefficients. For the development of fourth instar larvae, this parameter could be the 65th percentile value, where the development zero temperature and effective degree‐days were 11.1°C and 56 degree‐days, respectively.     

空心莲子草叶甲室内大量繁殖研究

为了大量繁殖供环境释放的空心莲子草叶甲Agasicles hygrophila以实现空心莲子草区域减灾, 我们探索出室内大量饲养与繁殖空心莲子草叶甲的方法与流程, 包括用叶片法或苗水培法孵化卵粒、用盒养法饲养各龄幼虫与成虫并供成虫产卵、用栽培活苗笼养法化蛹羽化。在室内成虫终日均能取食、交配、产卵, 产卵前期约4～5 d, 产卵高峰期在羽化后第7～24 天, 每雌平均产卵21.08块, 约570粒。盒养法叶片平均可着卵4.28块, 叶背与叶面着卵量相近; 笼养法叶片平均着卵为1.46块, 卵主要产于叶背。盒养法与笼养法得到的卵孵化率分别为94.02%与92.50%。空心莲子草叶甲除化蛹需在栽培活苗上完成外, 各龄幼虫与成虫均可用离体新鲜苗盒养法密集饲养。初孵1龄幼虫转株（叶）期、3龄老熟幼虫转化蛹苗期是室内大量饲养与繁殖空心莲子草叶甲的关键时期, 高密度成功饲养与繁殖空心莲子草叶甲的最适化蛹接虫量是每株8头, 产卵期雌虫的最适密度是每株5头。     

Use of day-degree estimates for rearing management of Ctenopseustis obliquana (Lepidoptera: Tortricidae) in the laboratory

Abstract

The brownheaded leafroller (BHLR), Ctenopseustis obliquana (Walker) (Lepidoptera: Tortricidae) was reared on an artificial diet at seven constant temperatures. The mean life cycle at optimum rearing temperature of 20 ± 1°C was: egg development 8.7 days; larval period, M 37.4, F 41.2 days; pupal period, M 14.9, F 13.3 days; pupal weights, M 50.5, F 68.2 mg; and a fecundity of 670 eggs per female. Estimated lower threshold temperatures and mean cumulative number of day- degrees for various stages of development were 7.8°C and 105D° for eggs, 5.2°C and 538D° for larvae, and 7.2°C and 186D° for pupa. Total mean day-degree accumulation from egg to adult was 829D°.

These data were used to develop an efficient rearing management system embracing colony maintenance, storage, manipulation, production, and quality assessment procedures.     

棉铃虫室内饲养技术的改进

在传统人工饲料饲养技术的基础上 ,对棉铃虫的卵、幼虫、蛹和成虫的饲养器材和操作方法进行了简化和改进。将产于纱布上的卵经消毒晾干后 ,直接放于塑料保鲜袋中孵化。初孵幼虫用毛笔移入特制的带盖 1 0孔饲养盒 ,每孔 1头 ,孔径和高度为 2 5cm× 1 8cm ,接虫前每孔加人工饲料 4～ 5g ,接虫后加盖 ,直至化蛹。幼虫化蛹后用培养皿收集 ,直接放于成虫饲养笼中 ,任其羽化、交配和产卵。采用这一改进饲养技术 ,幼虫存活率、化蛹率、羽化率等均有显著提高 ,棉铃虫的病害明显减少 ,同时节约饲养成本约 5 0 %。     

Effects of temperature increase caused by larval metabolism on the reproduction of Anagasta kuehniella (Lepidoptera: Pyralidae), a factitious host for Trichogramma

Many biological-control programmes, particularly those using egg parasitoids of the genus Trichogramma, involve rearing control agents on eggs of factitious hosts such as Anagasta kuehniella (Zeller). The objective of this study was to improve procedures for mass rearing of A. kuehniella, by determining the optimal population density in rearing trays, and evaluating the effects of metabolically induced temperature increase on reproduction and development. During the fourth and fifth instars, the temperature in trays increased 7–9°C, depending on larval density. Maximum egg production was obtained in trays inoculated with 10,800 eggs. Females and eggs obtained from this density were heavier than those reared at higher densities. Maintaining the temperature inside the rearing trays at 25°C increased egg production by up to 8?g per tray. However, both the heat from larval metabolism and the larval density significantly reduced the fecundity of A. kuehniella.     

Rearing larval stages of Hippodamia variegata Goeze (Col.: Coccinellidae) on artificial diet

The ladybird Hippodamia variegata Goeze is a widespread species found in many parts of the world. It is an efficient predator which feeds on a wide range of pests, specially aphids and other sap feeders. Mass rearing of this predator, in order to use in biological control programmes, entails a great deal of difficulties, among which are the aspects associated with nutrition. Applying artificial diets is of a great importance in mass rearing of biological control agents. We investigated the use of 15 artificial diets that included three separated experiments, in order to rear larval stages of this ladybird. The survival rate and developmental time were assessed on each treatment. The survival rate of the larvae on best diet was 53.30, 93.33, and 93.33% in different experiments. The developmental time in the experiment 1, 2 and 3 for the larva fed on the Aphis fabae was 15.59, 15.51 and 15.94, respectively, but when nourished by the best artificial diets, this factor was 26.59, 26.60 and 20.59, respectively. Developmental time for the larvae fed on A. fabae was significantly shorter than developmental time of larvae on artificial diets. Our results showed that artificial diets have the capacity to support the larval development to adulthood.     

Quality assessment of the predatory bugs Podisus maculiventris (Say) and Podisus sagitta (Fab.) (Heteroptera: Pentatomidae) after prolonged rearing on a meat—based artificial diet

The predatory stinkbugs Podisus maculiventris and Podisus sagitta were reared for more than 15 consecutive generations on a meat—based artificial diet. When they were returned to a diet of live prey (larvae of the pyralid Galleria mellonella) after different generations on the artificial diet, developmental and reproductive traits were similar to those of bugs continuously reared on live prey. Under laboratory conditions, predation rates for nymphs and adults of both pentatomids on larvae of the noctuid Spodoptera exigua were found to be unaffected by the previous diet. The results suggest that long—term rearing of P. maculiventris and P. sagitta on the meat—based artificial diet did not substantially affect the quality of the predators.     

Host-age-dependent parasitism and reproductive success of Apanteles stantoni (Hymenoptera: Braconidae), a larval parasitoid of Diaphania indica (Lepidoptera: Pyralidae)

The relative suitability of five instars of Diaphania indica (Saunders) (Lepidoptera: Pyralidae) as a substrate for the development of a larval parasitoid, Apanteles stantoni Ashmead (Hymenoptera: Braconidae), was investigated. Maximum parasitism (22.25?±?1.21%) under laboratory conditions was observed in the early larval instars. The highest parasitoid emergence was recorded from the second (86.07?±?0.70%) and third (98.93?±?0.72%) instar larvae of D. indica, and that from the first larvae was 71.43?±?1.18%. The number of cocoons in each cluster, length and width of single cocoons, percentage emergence, sex ratio and adult longevity of A. stantoni collected from different instars of D. indica were also recorded. These results indicated that the life stage of the host when the parasitoid larvae complete their final instar is particularly important for their development. Therefore, considering the efficiency of parasitism and reproduction, the second-instar larvae of D. indica is the most suitable stage for mass rearing A. stantoni in the laboratory.     

Optimization of diet and culture environment for larvae and juvenile freshwater pearl mussels,Hyriopsis (Limnoscapha) myersiana Lea, 1856

Summary

Culture of the freshwater pearl mussel, Hyriopsis (Limnoscapha) myersiana, was carried out in three consecutive steps: (1) culture of glochidia larvae in artificial media, (2) rearing the early juveniles (0–120 days old) in a nursery, and (3) rearing the juveniles (120–360 days old) in an earthen pond. The percentage survival of glochidia in standard tissue culture medium (M199) supplemented with common carp plasma was 95±2.5. All surviving larvae (100%) transformed to juveniles, the duration of transformation being 8 days. The early juveniles (0–60 days old) were fed with a mixture of four selected phytoplankton species (Chlorella sp., Kirchneriella incurvata, Navicula sp. and Coccomyxa sp.). The survival rate of juveniles was 8±0.2%. The average length of these juveniles increased from 0.13±0.01 mm to 1.41±0.16 mm and the average height from 0.16±0.01 mm to 0.98±0.09 mm. Subsequently, 60–120-day juveniles were fed with one of the same four phytoplankton species or a combination of the four. Feeding the juveniles with K. incurvata resulted in the highest survival rate (65±8.32%), with an average length of 3.46±0.04 mm and an average height of 1.94±0.04 mm. Finally, the 120–360-day juveniles were cultured in an earthen pond. There were progressive changes in average weight (0.0037±0.002 g to 11.24±5.02 g), length (3.48±0.39 mm to 54.08±6.21 mm), height (1.97±0.24 mm to 25.09±2.48 mm) and width (0.98±0.06 mm to 12.28±3.21 mm) from 120 to 360 days. The average growth rates per day of these parameters were 0.0497±0.01 g, 0.2414±0.15 mm, 0.0975±0.08 mm and 0.0493±0.03 mm, respectively. H. (L.) myersiana juveniles developed the complete structural composition of the adult by 160 days, and at 360 days, gametogenesis was complete.     

Response to rearing in laboratory of the xylophagous grape pest,Xylotrechus arvicola (Coleoptera: Cerambycidae)

Xylotrechus arvicola (Olivier) (Coleoptera: Cerambycidae) is an important pest in vineyards (Vitis vinifera) in the main Iberian wine‐producing regions. Larvae were reared with Semi‐Synthetic Iglesias (SSI) diet over 27 months and two generations in the laboratory. Larval mortality was highest during the first (49.49 %) and second (9.38 %) month of rearing, increasing to 50.52 % during the first month if F2 reared larvae were obtained from an F1 adult female obtained in laboratory. The diet had sufficient nutrients to enable the pest to complete its life cycle within nine months, with F1 larval viability ranging from 23.49 % to 27.97 % and F2 larval viability reduced to 2.07 %. However, the diet did not allow for the completion of additional life cycles and generations (F3, F4,…). Larval mortality increased as the months of rearing (66.13 %, 69.51 % and 89.50 %) and generations (59.10 % and 76.93 % in F1 and F2, respectively) progressed in the laboratory. The larva–adult period of females obtained in the laboratory was longer than for males. In the laboratory, the life cycle was shortened in relation to the life cycle in the field because larvae did not require a cold period to break diapause and start pupation. This indicates that X. arvicola has the potential to complete its life cycle inside grape wood in vineyards of wine‐producing regions with warmer winters.     

大螟人工饲养技术的初步研究

利用大豆粉、玉米粉、麦胚和鲜茭白等成分配制了大螟Sesamia inferens(Walker)的半合成人工饲料,利用该饲料配方,发展了大螟的长期、继代饲养技术,即初孵-2日龄幼虫在茭白上饲养,3日龄-化蛹在人工饲料上饲养。利用该方法连续饲养大螟3代,幼虫的发育历期、蛹重、幼虫存活率、化蛹率、羽化率、卵孵化率和单雌产卵量等生活史参数与在天然饲料茭白上饲养的大螟相比,二者没有任何显著差异。而且利用该方法饲养,成本低、省工省力,能显著减少病原菌的感染。这说明该饲养技术适于大螟种群的长期、继代饲养。     

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.     

Influence of larval food consumption on the fecundity of the lacewingChrysoperla carnea

The effects of food consumption on larval growth and development and adult fecundity of the common green lacewing,Chrysoperla carnea (Stephens), were studied on two populations of larvae derived from either a laboratory colony or from field-collected adults. The number of eggs of the Mediterranean flour moth,Anagasta kuehniella (Zeller), provided to individual lacewing larvae was varied to produce three food-supply treatments: low, intermediate, and high. Food-supply was found to influence larval growth and development and adult fecundity. Lacewing larvae provided with an overabundance of moth eggs developed faster than larvae provided with fewer moth eggs than they could have consumed. Adult females that developed from the high feeding treatment had a substantially shorter preoviposition period, a later decline in egg deposition, and a significantly higher fecundity than adults arising from the other feeding classes. Unrestricted feeding by adult lacewings on an artificial diet did not compensate for prior low feeding regimes. The overall performance of the lacewings derived from the laboratory colony was substantially poorer than that of the lacewings derived from field-collected adults. This effect was accentuated when the larvae were given a low food-supply. This overall decrease in vigor is attributed to inbreeding of the laboratory culture over a one year period. These finds are relevant to mass rearing programs for this biological control agent.