Growth and induction in food consumption of Helicoverpa armigera Hbn. (Lep., Noctuidae) larvae on chickpea, soybean, and maize diets

Laboratory studies were conducted to determine the effect of different artificial diets made of powdered seed materials of chickpea ( Cicer arietinum ), soybean ( Glycine max ), and maize ( Zea mays ) on the growth, consumption, and feeding preferences of Helicoverpa armigera larvae. Food consumption and growth of ultimate instar gram pod borer larvae were minimal on maize diet. The nutritive value of the soybean diet was higher, but the consumption rate of larvae was highest on chickpea diet compared with the other test diets. The growth of larvae was statistically equal on chickpea and soybean diets, in spite of differences in the consumption rate of these diets and their nutritive value. There appears to be a direct correlation between the quantity of the diets consumed and their nutritive value for growth of the larvae on chickpea and soybean diets. The lower nutritive value of chickpea diet is correlated with its higher intake by the larvae. Similarly, the lower consumption rate of larvae on soybean diet is correlated with its higher nutritive value. The diet on which the larvae were fed during earlier instars did not induce any feeding preference for that particular diet in the ultimate larval instar. The larvae consumed similar quantities of each of the three diets in their ultimate instar, irrespective of having fed on any of these diets during any preceding instars. However, induction in the quantitative consumption of food by the larvae was evident. The higher or lower consumption rate of diet by the larvae in the ultimate instar was influenced by their food during earlier instars. Hence the food consumption rate of larvae in the last instar appears to be set while feeding on a diet in the preceding instars.     

人工饲料与天然饲料饲养条件下烟青虫的生长发育和繁殖力比较

报道饲养烟青虫HelicoverpaassultaGue澖ee的一种人工饲料,比较了烟青虫取食该饲料和天然饲料的主要生物学指标,测定了6龄幼虫对2种食料的转化和利用率。该人工饲料的主要成分是麦胚、黄豆粉、酵母粉和烟叶粉,天然饲料为烟草叶片。结果表明:取食人工饲料的烟青虫幼虫生长发育快,化的蛹较大,成虫寿命长,产卵量大,所产卵孵化率高;取食人工饲料的烟青虫与取食烟草蒴果的相比,前者相对取食量和近似消化率较高,相对生长率无显著性差异。说明烟青虫对该人工饲料有较好的适应性,可以作为繁殖烟青虫的实用饲料。     

二化螟人工饲料研究初报

在温度为(29±1)℃,相对湿度为80%~90%的条件下,分别以3种人工饲料和天然饲料(新鲜水稻茎杆)对二化螟Chilo suppressalisWalker进行连续继代饲养。结果表明,3种人工饲料饲养的二化螟幼虫的生长历期、化蛹率、蛹重、蛹期及羽化率等均与天然饲料的基本接近,而且这3种人工饲料配制简便、成本较低,也不易霉变,是3种较为理想的人工饲料。通过第2代和第3代的继代繁殖表明,3种人工饲料和天然饲料饲养的二化螟的发育情况都稍有下降,但3种人工饲料与天然饲料间不存在显著差异。     

Comparison of artificial diets for rearing Bracon hebetor Say (Hymenoptera: Braconidae)

The ectoparasitoid Bracon hebetor Say is an insect frequently found in storage facilities, where it attacks stored grain pests. The biology of this parasitoid was studied when reared on seven different artificial diets (in vitro rearing), under controlled temperature (25 ± 2 °C), relative humidity (60 ± 10%), and photoperiod (14-h photophase), and compared to its biology on its natural host Anagasta kuehniella (Zeller) (in vivo rearing). The artificial diet contained 60% holotissue of Diatraea saccharalis (Fabricius) pupae, 12% fetal bovine serum, 12% lactoalbumin hydrolysate, and 16% egg yolk, enabled development similar to that obtained on the natural host. The life cycle duration (egg–adult) was not significantly different, and the adults reared on this diet promptly paralyzed and parasitized the natural host, though at a lower proportion than those reared in vivo. There was no difference in the longevity of females obtained with these two different rearing systems (in vivo and in vitro). However, about 60% of the larvae developed on the diet failed to produce a protective cocoon during the pupal phase, indicating a sub-optimal quality associated with this artificial medium.     

Effects of two artificial diets on the development and reproduction of Tirathaba rufivena (Walker) (Lepidoptera: Pyralidae)

Growth, survival, fecundity, and nutrition of Tirathaba rufivena (Walker) fed on two artificial and one natural diet were studied at 29±1°C and 75±5% relative humidity. Larvae reared on the two artificial diets showed faster growth and development, higher pupal survival and weight, and higher adult fecundity than those reared on a natural diet of young coconuts, Cocos nucifera L. The relative growth rate, efficiency of ingested food conversion, and efficiency of digested food conversion in larvae fed on artificial diets were significantly higher than those of larvae fed on young coconuts. The relative consumption rate of larvae fed on artificial diets was significantly lower than that of larvae fed on young coconuts. T. rufivena showed no significant degradation in ability to propagate after being reared on the artificial diet for five successive generations. These results indicated that two artificial diets are suitable for mass rearing of T. rufivena.     

A method for rearing and assessing the health of the sugarcane pest Dermolepida albohirtum (Coleoptera: Scarabaeidae)

Rearing insects in controlled conditions is a prerequisite to supply high-quality specimens for bioassays. However, while artificial diets and standardized rearing methods have been developed for many phytophagous insects, especially Lepidoptera, there are limited published diets for root-feeding Coleoptera which are commonly fed either grass roots or pieces of vegetables as a simple alternative to artificial diets during bioassays. These feeding options, while convenient, can be considered suboptimal as they do not maximise the insects' development and health. Additionally, it is also important to develop standardised screening methods designed to test sublethal effects of control agents which may have repellent, antifeedant, antimetabolic and/or delayed mortality effects. The greyback canegrub (Dermolepida albohirtum, Waterhouse) is the most damaging native pest of Australian sugarcane, but no rearing method or artificial diet has ever been developed for this species. Our objectives were to improve bioassay methodology for D. albohirtum by describing and developing standard rearing and health assessment protocols. We describe a successful rearing method to raise healthy D. albohirtum larvae with a total of 48.8% of first instars successfully moulting to the second instar. We also tested a modified artificial diet which increased the weight, size and food uptake of larvae compared to traditional methods (i.e., pieces of carrots). For example, the average weight increase of larvae fed with the modified diet was 3.4 times higher than for carrot-fed larvae while modified diet-fed larvae were 2.1 times wider than if they were fed with carrots. Finally, we developed a method to measure larval activity which can be used to identify sublethal effects of control agents such as effects on activity level. Our methods may also be applied to improve bioassay methodology for other root-feeding Coleoptera.     

Artificial diets for rearing the coconut hispine beetle Brontispa longissima and its parasitoid Asecodes hispinarum

We tested artificial diets for rearing the coconut hispine beetle, Brontispa longissima, a serious invasive pest of coconut (Cocos nucifera) in Southeast Asia. We examined three artificial diets that were identical except for their agar content. The survival rate from hatching to adult emergence was 26.0% when beetles were reared on a ‘soft diet’ (20 g/l agar), 16.0% on a ‘hard diet’ (40 g/l agar), and 41.0% on a ‘mixed diet’, in which the hard diet was used for the first instar and the soft diet for later instars. Females raised as larvae on the mixed diet and then as adults on the soft diet laid few eggs, which did not hatch. However, females reared on the mixed diet as larvae and then on fresh leaves as adults consistently laid eggs that hatched. We then examined the suitability of B. longissima larvae reared on the mixed diet as hosts for the larval parasitoid Asecodes hispinarum, a specialist parasitoid of this beetle. Of the oviposited hosts, 75.0% became mummified and 41.7% produced adult wasps. These results indicate that the mixed diet may be useful for rearing B. longissima larvae as hosts for the rearing of A. hispinarum.     

Host rearing is a bottleneck for classical biological control of the cherry bark tortrix: A comparative analysis of artificial diets

This paper describes a comparative analysis of the suitability of three artificial diets for the development of the cherry bark tortrix (CBT), Enarmonia formosana Scopoli (Lepidoptera: Tortricidae), to simplify the rearing process for this species and its potential classical biological control agents. The three diets tested included (1) a pinto bean-based diet modified specifically for the CBT, (2) the diet for codling moth, Cydia pomonella Linnaeus (Lepidoptera: Tortricidae), and (3) the Singh general-purpose diet. Survival from first instar to the pupal stage was very low on the pinto bean, codling moth, and Singh general-purpose diets (29, 0, and 0%, respectively). Survival was consistently greater, yet still low, for larvae that were reared through the first instar on bark and subsequently transferred to the codling moth or Singh general-purpose diets (5 and 32%, respectively). In comparison, larvae started on the pinto bean diet as second instars had a survival rate of 90%, only slightly below that of sibling larvae from the cherry bark control group (100%). Larval development time was fastest on cherry bark (36±2?days), differing significantly from that on the pinto bean diet (started as first instars: 58±2?days; started as second instars: 46±2?days), but not from the development time of larvae on the Singh general-purpose diet (44±3?days). Pupal weights were greatest for specimens from the Singh general-purpose diet (14.9±0.5?mg) and lowest for those from the pinto bean diet (started as first instar: 12.3±0.6?mg; started as second instar: 12.1±0.4?mg). Pupal weights from cherry bark were intermediate (13.5±0.6?mg). Early mortality, resulting primarily from rejection of the diet, remains to be the critical impediment in CBT rearing. It is therefore suggested that a phagostimulant from cherry bark be identified and included in an artificial diet shown to be nutritionally suitable, such as the Singh general-purpose diet or the pinto bean diet.     

Feeding behavior and growth of corn earworm (Lepidoptera: noctuidae) larvae on Bacillus thuringiensis-treated (dipel 4L) and untreated meridic diet

The effect of Dipel 4L in artificial diet on feeding behavior, occurrence on a specific diet, and growth of corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), was assessed in short-term tests. Third-, fourth-, and fifth-stage laboratory-reared and feral corn earworm larvae were evaluated. Arenas used for each assay included a non-Dipel diet, Dipel-containing diet, and a combination of the two diets. Larval activity was observed immediately after exposure to diet and at 6 and 18 h for third instars and at 6, 8, and 24 h for fourth and fifth instars, respectively. Feral and laboratory-reared third, fourth, and feral fifth instars avoided Dipel-treated diet when more suitable food was available. Third and fourth instars consistently preferred non-Dipel-containing diet when presented a choice of foods. Corn earworm growth was delayed when larvae were subjected to Dipel-treated diet in choice and no-choice assays compared with larvae provided untreated diet. Larvae presented a choice of diets grew more rapidly than those presented Dipel-treated diets in no choice arenas. Larval feeding frequency and weight gain were superior when larvae were supplied untreated diet than when restricted solely to a Dipel-treated diet. Larvae presented a choice of diets spent more time feeding and fed more frequently on untreated diet than Dipel-treated food. These data indicate that corn earworm presented a choice of Bacillus thuringiensis (Bt) and non-Bt diets may have an increased probability of completing development compared with those restricted to Bt-laced sources.     

Performance and feeding behavior of Ceratitis capitata: comparison of a wild population and a laboratory population

Experiments were carried out to test the performance and some aspects of feeding behavior in two populations of Ceratitis capitata (a population reared in the laboratory for 16 years, i.e., approximately 160 generations, and a wild one obtained from infested coffee, Coffea arabica grains). Two types of food were used in the experiment: an artificial yeast diet used for laboratory rearing and papaya (Carica papaya), a natural host of the fly. The performance parameters tested were percent emergence, time to emergence, adult female size, and egg production during the pre-oviposition phase (first five days of adult life). The behavioral aspects tested were food preference by newly hatched larvae, induction, estimated ingestion of the two diets, whether the larvae placed on one diet stayed there or moved to the other diet, and acceptance of food for oviposition. The results indicated that the performance of the wild population was superior when the flies fed on papaya, whereas the performance of the laboratory population was similar with the two diets; the wild population showed a strong preference for papaya in all choice experiments, whereas the laboratory population showed no diet preference; the females of the wild population only oviposited on pieces of papaya that had not been peeled, and did not oviposit in the artificial diet; the females of the laboratory population oviposited indiscriminately on unpeeled and peeled papaya and on the artificial diet.     

Effects of class-specific,synthetic, and natural proteinase inhibitors on life-history traits of the cotton bollworm Helicoverpa armigera

Herbivorous insects have more difficulty obtaining proteins from their food than do predators and parasites. The scarcity of proteins in their diet requires herbivores to feed voraciously, thus heavily damaging their host plants. Plants respond to herbivory by producing defense compounds, which reduce insect growth, retard development, and increase mortality. Herbivores use both pre- and postdigestive response mechanisms to detect and avoid plant defense compounds. Proteinase inhibitors (PIs) are one example of plant compounds produced as a direct defense against herbivory. Many insects can adapt to PIs when these are incorporated into artificial diets. However, little is known about the effect of PIs on diet choice and feeding behavior. We monitored the diet choice, life-history traits, and gut proteinase activity of Helicoverpa armigera larvae using diets supplemented with synthetic and natural PIs. In choice experiments, both neonates and fourth-instar larvae preferred the control diet over PI-supplemented diets, to varying degrees. Larvae that fed on PI-supplemented diets weighed less than those that fed on the control diet and produced smaller pupae. Trypsin-specific PIs had a stronger effect on mean larval weight than did other PIs. A reduction of trypsin activity but not of chymotrypsin activity was observed in larvae fed on PI-supplemented diets. Therefore, behavioral avoidance of feeding on plant parts high in PIs could be an adaptation to minimize the impact of this plant's defensive strategy.     

Development,survival, body weight,longevity, and reproductive potential of Oemena hirta (Coleoptera: Cerambycidae) under different rearing conditions

Oemona hirta (F.) is a New Zealand native longicorn beetle, whose larvae bore into the wood of branches and stems of living trees and vines, causing serious damage. To explore effective methods for maintaining laboratory colonies and biology of immature stages of this species we evaluated four laboratory rearing methods with both natural and artificial diets and compared biological parameters of laboratory colonies with those of field-collected insects. On an artificial diet, approximately 40% of neonate and 70% of autumn- and 11% of winter-collected larvae reached adulthood. Neonate larvae could not complete their development in cut poplar (Populus nigra variety italica Koehne) twigs; however, when twigs were standing in water >46% of neonate larvae survived to adulthood. Mean larval development time ranged from approximately150 to almost 300 d, depending on rearing methods. Mean pupal stage ranged from 15 to 19 d. Adult females were significantly heavier than males. Although adult females from field-collected twigs and reared on the artificial diet had similar mean body weight, which was significantly greater than that of other rearing colonies, the potential fecundity was the highest in the former (83.1 +/- 29.4 eggs) and the lowest in the latter (33.5 +/- 9.1 eggs). In all laboratory-reared and field-collected insects, the total number of eggs produced (eggs laid + eggs that remained in dead female body) by females was positively correlated with their body weight. When larvae fed on the artificial diet, there was no positive correlation between the number of eggs successfully laid and female body weight. However, when larvae lived on natural food, a positive correlation was found. In laboratory colonies, mean longevity of females (36 to 52 d) was slightly greater than that of males (30 to 50 d) without significant difference between sexes but in the adults from field-collected twigs, males (52 d) lived significantly longer than females (33 d). In terms of time, labor, and the number of resulting adults, collecting larvae in the field in autumn and then transferring them onto artificial diet is the most effective method for maintaining a laboratory colony.     

二种改进人工饲料对红脉穗螟生长发育和繁殖的影响

在温度(29±1)℃和相对湿度75%±5%条件下,研究了2种改进人工饲料和天然饲料椰子幼果对红脉穗螟Tirathaba rufivena Walker生长发育、繁殖力和营养的影响。结果表明:与天然饲料相比,用改进人工饲料饲养的红脉穗螟幼虫生长发育速度、幼虫存活率、蛹重及产卵量均提高;幼虫相对生长率(RGR)、食物利用率(ECI)及食物转化率(ECD)均显著提高,而相对取食量(RCR)则显著降低。表明红脉穗螟幼虫对2种人工饲料有很好的适应性,可用于大量饲养。     

The development of a synthetic diet for investigating the effects of macronutrients on the development of Plodia interpunctella

The use of chemically defined artificial diets has allowed researchers to examine questions within nutritional ecology about how macronutrients affect life‐history traits and resource‐based trade‐offs. Using a chemically defined diet, it is possible to manipulate both the total nutritional content and the ratio of macronutrients (i.e., proteins, carbohydrates, or lipids) within the diet. Studies using the geometric framework have made use of these diets to examine lifespan, fecundity, and immune responses. Here, we develop an artificial diet suitable for rearing lepidopteran larvae. We created diets with three proportions of non‐nutritive material (30, 50, and 70% indigestible cellulose) relative to protein and carbohydrate macronutrients, and compared these to standard wheat bran laboratory diet. We then examined the effects of variable nutrient content on lifespan and development time in Plodia interpunctella Hübner (Lepidoptera: Pyralidae). The artificial diets supported development (almost) as well as bran‐based laboratory diets. Total nutrient content affected development time: females that fed on the diet with the highest nutrient content took the longest time to reach eclosion. We also found evidence to support dietary restriction, with larvae receiving the fewest nutrients having the longest lifespan as adults. These findings are indicative of the usefulness of this diet as a tool to further investigate the effects of nutrient content and macronutrient imbalance on resource‐based trade‐offs and life‐history traits.     

Performance of Lymantria xylina (Lepidoptera: Lymantriidae) on artificial and host plant diets

Lymantria xylina Swinhoe (Lepidoptera: Lymantriidae) is a serious defoliator of hardwood and fruit trees in Taiwan. The larvae of L. xylina feed on >63 species of host plants, belonging to 29 families. Because a large number of larvae are needed for the production of nucleopolyhedrosis virus (NPV) or other related studies, the development of a suitable artificial diet is very important for the mass rearing of this moth in the laboratory. In this study, eight artificial diets, modified from different formulas, and one host plant, Liquidambar formosana Hance, were used to feed L. xylina caterpillars. Through various bioassays (first instar survival trial and long- and short-term feeding trials), the most suitable diet for the L. xylina was selected by performance comparisons with L. formosana. After the first instar survival trial, two of the diets were discarded, because no larva survived on these diets. The results of the long-term feeding trial indicated that the larvae grew successfully on only three kinds of artificial diet. Finally, results of the short-term feeding trial revealed that a diet (diet A), modified from the gypsy moth, Lymantria dispar (L.), formula diet, was the most appropriate for the L. xylina. Larvae fed on diet A had better survival rate, pupal weight, adult size, efficiency of conversion, and relative growth rate than larvae fed on other diets; they did not grow as well as those fed on L. formosana, however, except for pupal and adult weight, and approximate digestibility. In summary, diet A was found to be the best of the artificial diets for the L. xylina and is suitable for mass rearing of this moth in the laboratory.     

Benefits and limitations of factitious prey and artificial diets on life parameters of predatory beetles,bugs, and lacewings: a mini-review

The primary peer-reviewed literature pertaining to rearing of predatory beetles, true bugs, and lacewings was reviewed and synthesized. This study focused on the literature published from 1998 to 2007. Advances in rearing were revealed in relation to the influence of factitious prey and artificial diets on predator life parameters. Eggs of the Angoumois grain moth and Mediterranean flour moth were factitious prey that supported the development and reproduction of many species in lieu of natural prey. Artificial diets based on vertebrate protein were generally inferior to factitious prey for production of predators. A few exceptional cases demonstrated potential for continuous rearing of true bugs and lacewings on artificial diet, as a stand-alone food source. Factors that could ensure progressive rearing success might involve (1) exploiting the highly polyphagous nature of certain species, (2) exposing predators to artificial diet for multiple generations to incite adaptation, (3) formulating artificial diets to match the texture and chemical composition of preferred natural prey, and (4) encasing the diet within Parafilm^® to resemble the shape of natural prey. Encasement may also reduce desiccation and retard spoilage of the diet. Identification of other factitious prey and development of artificial diets that ensure production of predators of high quality should be possible. This review was conducted, for the most part, in support of generalist insect predators used, or having the potential to be used, in augmentative biological control of pests on plants in semi-closed systems, such as greenhouses and interiorscapes.     

Diet-switching by gypsy moth: effects of diet nitrogen history vs. switching on growth, consumption, and food utilization

Gypsy moth (Lymantria dispar (L.) (Lepidoptera: Lymantriidae)) larvae were reared from hatch on 1.25% N or 3.5% N artificial diet (previous diet) and switched reciprocally to the other diet (current diet) after molting into the second, third, fourth, or fifth instar. The nitrogen concentration of food consumed during previous instars had a strong residual effect on the growth rate in subsequent instars when a diet switch was made during instars two through four, but did not affect growth rate of fifth-instar larvae despite effects on food consumption and utilization. In early instars, larvae reared on 1.25% N artificial diet and then switched to 3.75% N diet had lower mass-adjusted growth rates than larvae continuously reared on 3.75% N diet. Conversely, larvae reared on 3.75% N diet and switched to 1.25% N had higher mass-adjusted growth rates than larvae reared continuously on 1.25% N diet. Relative to larvae previously reared on 1.25% N diet, fifth-instar male larvae previously reared on 3.75% N diet had slightly lower consumption rates, higher net growth efficiency (ECD), and higher gross growth efficiency (ECI). Larvae previously reared on 3.75% N diet tended to have lower food assimilation efficiency (AD) and lower nitrogen assimilation efficiency (AD(N)). Although both previous and current diet nitrogen concentration strongly affected larval growth and food utilization, the interaction term between these was not significant for any response variables except ECD and ECI. Because the interaction term reflects the effect of switching per se, the results indicate that there was a metabolic cost associated with switching, but no inherent net cost or benefit of diet-switching to growth.     

Host hemolymph proteins and protein digestion in larval Habrobracon hebetor (Hymenoptera: braconidae)

Host plasma proteins and protein digestion in larval parasitoids were studied during trophic interactions of the ectoparasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae), with a host, larvae of the Indianmeal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). We could detect no apparent differences in host hemolymph protein patterns up to 72 h after paralysation and/or parasitization by H. hebetor. A 190 kDa putative apolipophorin I present in host hemolymph could not be detected in the midguts of feeding H. hebetor larvae indicating that it is rapidly digested. The major 60 kDa storage proteins (putative hexamerins) in host hemolymph were detected in the parasitoid midgut and were completely digested 24 h after cessation of feeding and the beginning of cocoon formation. Host hemolymph had a pH of about 6.4. The pH optima of the midgut proteinases in the larval parasitoid were in the alkaline region, but midgut fluid in feeding parasitoid larvae was about pH 6. 8. Based on enzyme activity against selected artificial proteinase substrates including azocasein, N-alpha-benzoyl-L-Arg p-nitroanilide (BApNA), succinyl-Ala-Ala-Pro-Phe p-nitroanilide (SAAPFpNA), succinyl-Ala-Ala-Pro-Leu p-nitroanilide (SAAPLpNA), and inhibition by selected proteinase inhibitors, serine proteinases appear to be the predominant class of enzymes involved in protein digestion in the midguts of H. hebetor. There is also an active aminopeptidase (LpNA) associated with the microsomal fraction of midgut preparations. There was no evidence for preoral digestion or ingestion of proteinases from host hemolymph by the parasitoid larva. There was a very active BApNAase in the soluble fraction of midgut extracts. This activity increased on a per midgut basis up to 24 h after the beginning of cocoon formation but decreased rapidly by 48 h. Two major (P1 and P3) and several minor proteinases were detected in midgut extracts of H. hebetor analysed with gelatin zymograms. The apparent molecular mass of P1 varied from 95 to 49 kDa depending on protein loading. P3 had an apparent molecular mass of 39 kDa that was independent of protein loading. In summary, electrophoretic evidence indicates that host hemolymph protein patterns do not change significantly for at least 72 h after paralysation by H. hebetor. The role, if any, of envenomization in preventing breakdown of hemolymph proteins during this time remains to be determined. Because the predominant host hemolymph proteins, a putative apolipophorin I and the putative hexamerins, are readily digested by the serine proteinases present in the midguts of this parasitoid larva, these or similar proteins would provide an easily digested source of dietary amino acids that could be used for development of artificial diets for this beneficial insect.     

Performance of the Wheat Armyworm, Pseudaletia sequax Franclemont, on Natural and Artificial Diets

Armyworms in the genus Pseudaletia Franclemont are important pests of cereal crops worldwide. The development of pest management strategies is largely dependent on studies involving the relationship among the pest, its host plants and natural enemies, as well as its susceptibility to chemical and biological control strategies. Part of these studies requires rearing the species of interest under laboratory conditions, which can be greatly facilitated by the use of artificial diets. In the present study, the effects of three artificial diets on development, survival, reproduction and demographic parameters of P. sequax were compared to a natural host plant, Pennisetum clandestinum. A diet based on pinto beans, wheat germ and torula yeast provided the best results in comparison to those obtained with the host plant. The most important life history parameters used in the evaluation of the nutritional quality of the diets were fecundity, egg viability and pupae deformities. The intrinsic rate of increase and the net reproductive rate were higher when individuals were fed on the artificial diet if compared to the host plant, indicating the suitability of the tested diet for the rearing of P. sequax. This artificial diet has been used successfully for the rearing of P. sequax without any fitness effect for over 18 consecutive generations.     

Artificial diets for the larval oak longicorn beetle, <Emphasis Type="Italic">Moechotypa diphysis</Emphasis> (Coleoptera: Cerambycidae)

The oak longicorn beetle, Moechotypa diphysis (Pascoe), is a pest of bed logs for shiitake mushroom and an invasive species on Japan’s main islands. I attempted to rear larvae of M. diphysis on two artificial diets consisting of a commercially available diet for silkworm plus dried yeast and sawdust of the sawtooth oak, Quercus acutissima Carruthers, or of Japanese beech, Fagus crenata Blume. Newly hatched larvae were inoculated on these artificial diets and reared at 25°C in the dark. More than 60% of larvae emerged as adults when fed with these diets. The weights of emerged adults fed on the artificial diets were heavier than those emerging from logs of Q. acutissima, their natural diet, in a field cage. These results demonstrate that the two artificial diets are useful for rearing M. diphysis larvae and can assist further studies on the development of this invasive species.