Effective bioconversion of farmed chicken products by black soldier fly larvae at commercially relevant growth temperatures

Global population growth and an increasing demand for meat has driven the intensification of livestock production. On poultry farms, the accumulation of waste such as faeces, carcasses and unsellable eggs creates environmental and health hazards that need to be mitigated. The larvae of the black soldier fly (Hermetia illucens; BSFL) offer a potential solution to the problems of waste management on poultry farms. BSFL consume large quantities of organic waste and convert it into larval biomass, which can then be processed for use as livestock feeds or biofuels. This makes BSFL an ideal candidate for value-added waste management on chicken farms. Here, we examined the development and nutrient profile of BSFL given five different diet treatments: poultry feed (control), chicken meat, chicken egg, chicken manure and a mixture of equal parts chicken meat, egg and manure. Chicken meat, egg and mixed diets were all found to be suitable feedstocks for BSFL, but the manure-only treatment was associated with a high failure rate of larval development. Mixing manure with other poultry waste streams ameliorated the negative impacts of manure on BSFL. Larvae reared on chicken meat, egg and the mixed diet had equal or higher mean crude protein (CP) (39.9%, 33.8% and 31.5%, respectively) and crude lipid (CL) contents (30.1%, 29.00% and 28.7%, respectively), compared with BSFL reared exclusively on chicken feed (CP: 30.9%, CL: 23.8%), demonstrating the suitability of these waste-stream diets for the potential animal feed quality of the BSFL. We discuss how BSFL bioconversion could be implemented to address environment management issues on poultry farms.     

非水虻源微生物与武汉亮斑水虻幼虫联合转化鸡粪的研究

【目的】益生微生物在协助亮斑扁角水虻幼虫转化有机废弃物、提高其转化效率方面具有重要的作用,本研究针对非水虻源微生物,开展与水虻联合转化鸡粪的研究,以阐明外源微生物在水虻转化畜禽粪便中的作用,对其转化机制的研究及产业化生产具有重要意义。【方法】采用稀释涂平板的方法进行鸡粪堆肥和猪粪堆肥中细菌的分析,并将筛选到的细菌分别接种到无菌的鸡粪基质中与武汉亮斑水虻幼虫联合转化,通过称重法测定转化后武汉亮斑水虻及鸡粪的重量,评价转化效果及对幼虫的影响,然后将促进转化效果明显的菌株按不同比例进行复配,与武汉亮斑水虻幼虫联合转化新鲜鸡粪,分析复配菌剂对武汉亮斑水虻幼虫转化鸡粪的影响。【结果】结果显示R-07、R-09、F-03和F-06在促进武汉亮斑水虻幼虫生长和鸡粪转化的效果上最为显著。与对照组相比,水虻幼虫转化率分别提高了27.21%、15.00%、9.93%和16.29%;基质减少率分别提高了17.94%、10.42%、7.84%和9.27%。将这4株细菌配制复配菌剂与武汉亮斑水虻幼虫联合转化鸡粪,结果显示复配比例为R-07:R-09:F-03:F-06=4:1:1:1时效果最好,与空白对照相比,武汉亮斑水虻幼虫存活率提高了10.25%,幼虫虫重增加了28.41%,幼虫转化率增加了30.46%,鸡粪减少率增加了7.69%。【结论】添加通过筛选优化的非水虻来源的微生物复合菌剂能够促进水虻高效转化鸡粪,研究结果有助于改善现有的武汉亮斑水虻幼虫转化体系,为开发新型的联合转化工艺、更加有效地处理畜禽粪便奠定基础。     

Enhancement of fruit byproducts through bioconversion by Hermetia illucens (Diptera: Stratiomyidae)

Bioconversion is a biological process by which organic materials are converted into products with higher biological and commercial value. During its larval stage the black soldier fly Hermetia illucens is extremely voracious and can feed on a wide variety of organic materials. To study the impact of different fruit byproducts on the insect's growth, final larval biomass, substrate reduction, bioconversion parameters, and larval nutritional composition, 10 000 black soldier fly larvae (BSFL) were reared on 7.0 kg of one of three substrates (strawberry, tangerine, or orange) or on a standard diet as a control. The results highlight that BSFL can successfully feed and grow on each of these diets, though their development time, growth rate, and final biomass were differently impacted by the substrates, with strawberry being the most suitable. The lipid and protein contents of BSFL were similar among larvae fed on different substrates; however, major differences were detected in ash, micronutrient, fiber, fatty acid, and amino acid contents. Overall, the results indicate that fruit waste management through the BSFL bioconversion process represents a commercially promising resource for regional and national agrifood companies. Our study offers new perspectives for sustainable and environmentally friendly industrial development by which fruit byproducts or waste might be disposed of or unconventionally enhanced to create secondary products of high biological and economic value, including BSFL biomass as animal feed or, in perspective, as alternative protein source for human nutrition.     

Characteristics and nutrient function of intestinal bacterial communities in black soldier fly (Hermetia illucens L.) larvae in livestock manure conversion

The potential utility of black soldier fly larvae (BSFL) to convert animal waste into harvested protein or lipid sources for feeding animal or producing biodiesel provides a new strategy for agricultural waste management. In this study, the taxonomic structure and potential metabolic and nutrient functions of the intestinal bacterial communities of BSFL were investigated in chicken and swine manure conversion systems. Proteobacteria, Firmicutes and Bacteroidetes were the dominant phyla in the BSFL gut in both the swine and chicken manure systems. After the larvae were fed manure, the proportion of Proteobacteria in their gut significantly decreased, while that of Bacteroidetes remarkably increased. Compared with the original intestinal bacterial community, approximately 90 and 109 new genera were observed in the BSFL gut during chicken and swine manure conversion, and at least half of the initial intestinal genera found remained in the gut during manure conversion. This result may be due to the presence of specialized crypts or paunches that promote microbial persistence and bacteria–host interactions. Ten core genera were found in all 21 samples, and the top three phyla among all of the communities in terms of relative abundance were Proteobacteria, Firmicutes and Bacteroidetes. The nutrient elements (OM, TN, TP, TK and CF) of manure may partly affect the succession of gut bacterial communities with one another, while TN and CF are strongly positively correlated with the relative abundance of Providencia. Some bacterial taxa with the reported ability to synthesize amino acids, Rhizobiales, Burkholderia, Bacteroidales, etc., were also observed in the BSFL gut. Functional analysis based on genes showed that intestinal microbes potentially contribute to the nutrition of BSFL and the high-level amino acid metabolism may partly explain the biological mechanisms of protein accumulation in the BSFL body. These results are helpful in understanding the biological mechanisms of high-efficiency nutrient conversion in BSFL associated with intestinal microbes.     

黑水虻幼虫处理餐厨垃圾过程中体内养分组成与消化酶活性变化规律的研究

黑水虻Hermetia illucens作为一种新型资源环境昆虫,其幼虫可以处理餐厨垃圾、畜禽粪便、蔬菜残体等各种有机废弃物。幼虫富含蛋白质和油脂,可以作为水产饲料的蛋白来源。本研究探索黑水虻幼虫处理餐厨垃圾过程中其养分组成与消化酶活性变化之间的关系。通过黑水虻幼虫自由取食餐厨垃圾,每日采集样品用于物质养分和消化酶活性的测定。结果显示：黑水虻幼虫粗蛋白含量呈现先下降后上升的变化规律,而幼虫总糖含量呈现先上升后下降的变化规律,粗脂肪含量维持上升的趋势。幼虫处理餐厨垃圾过程中,体内蛋白酶在初期迅速上升,第6天后逐渐下降,而淀粉酶呈现出先缓慢上升再迅速上升最后下降的变化规律。脂肪酶在黑水虻幼虫处理餐厨垃圾前期保持较高的活性然后缓慢下降。同时,通过相关性分析,黑水虻幼虫粗蛋白含量变化与蛋白酶活性没有相关性,而总糖与粗脂肪含量变化分别与淀粉酶、脂肪酶有相关性。因此,部分消化酶活性变化与黑水虻幼虫养分组成具有一定的联系,本研究结果为工厂化养殖黑水虻提供一定的理论基础。     

Evaluation of a pelleted diet for larval mass-rearing of Anastrepha ludens and Anastrepha obliqua

Most artificial diets used for mass-rearing of fruit fly larvae involve the purchase and independent weighing of each ingredient of the formulation, followed by mixing and diet preparation process. A ready-to-use formulation would avoid this time-consuming task and simplify the preparation procedure, leading to a more standardized diet. In this work, we compared life-history traits and survival and developmental parameters of Anastrepha ludens Loew and Anastrepha obliqua (Macquart) (Diptera: Tephritidae) reared on two formulations of an artificial diet. Two experiments were performed; first, a conventional non-pelleted diet was compared to a newly developed pelleted diet, which was mixed with water before being given to the larvae. The second experiment consisted of a comparison between the pelleted diet which was stirred in a mixer with water and dissolved preservatives and a pelleted diet which was only soaked in water with dissolved preservatives. We found that the pelleted diet allowed the mass-rearing of A. ludens and A. obliqua. Moreover, feeding larvae with pelleted diet led to increased weight of the larva by 7.4 and 11.8%, and of the pupa by 9.5 and 16.7% for A. ludens and A. obliqua, respectively, compared to conventional diet. For process evaluation, the number of activities, handling time, reception, storage, and larval diet preparation were recorded. The pelleted diet only needed soaking in water containing preservatives, thereby simplifying the mass-rearing process and saving time, space, and labour. Pelletizing is a versatile technology that can be adjusted for better physicochemical quality and reduced microbiological risk. This diet should be of particular interest for the mass-rearing process in ‘sterile insect technique’ applications.     

Rapid evolution of larval development time during mass-rearing in the melon fly, Bactrocera cucurbitae

A quantitative genetic analysis of rapid evolution of a life history trait has been conducted on the first 24 generations of mass-rearing in the melon fly Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae). The phenotypic variance of larval development time in each generation was divided into genetic and residual components. Mean and phenotypic coefficients of variation of larval development time decreased gradually as generations proceeded as a result of artificial selection for shorter larval period in the mass-rearing procedure. There was a trend that additive genetic coefficients of variation in larval development time decreased with generations. These changes are entirely attributed to genetic responses to laboratory selection under the mass-rearing environment because the population was maintained at a very large size so as to exclude random genetic drift and inbreeding depression, which would be other factors responsible for the observed genetic changes. The residual coefficients of variation in larval development time did not change with generations. Realized heritability of larval development time was low. The heritabilities for larval development time estimated from parent–offspring regression at generations 60 and 70, when the evolutionary plateau was asymptotically reached, were not significantly larger than 0. Received: April 22, 1999 / Accepted: September 20, 1999     

The consequences of alternating diet on performance and food preferences of a specialist leaf beetle

The food quality of a given host plant tissue will influence the performance and may also affect the preference behavior of herbivorous animals. As nutrient contents and defense metabolite concentrations can vary significantly between different parts of a plant and change over time, herbivores are potentially confronted with diet differing in quality even when feeding on a single plant individual. Here we investigated to what extent feeding exclusively either on young or old, mature leaves of Brassica rapa or on a mixed diet of young and old leaves offered in alternating order affects the larval performance, food consumption, and the host preference behavior of adult mustard leaf beetles, Phaedon cochleariae. Analyzing different leaf quality traits, we found lower water contents, no changes in C:N ratio but more than threefold higher glucosinolate concentrations in young compared to old leaves. Individuals reared on mixed diet performed as well as animals reared on young leaves. Thus, compared to animals feeding exclusively on highly nutritious young leaves, diet-mixing individuals may balance the lower nutrient intake by a dilution of adverse secondary metabolites. Alternatively, they may integrate over the variation in their food, using a previously assimilated resource for growth at times of scarcity. Animals reared on old leaves grew less and had a prolonged larval developmental time, although they showed increased consumption indicating compensatory feeding. Additionally, we found that experience with a certain diet affected the preference behavior. Whereas individuals reared exclusively on young leaves preferred young over old leaves for feeding and oviposition, we did not find any preferences by animals reared exclusively on old leaves or by females reared on alternating diet. Thus, in contrast to positive feedbacks for animals reared on young leaves, an integrative growth of diet-mixing individuals potentially leads to a lack of feedback during development. Taken together, our results suggest that different diet regimes can lead to comparable performance of mustard leaf beetles but experienced feedbacks may differ and thus convey distinct diet preferences.     

The first insight into black soldier fly meal in brown trout nutrition as an environmentally sustainable fish meal replacement

Insect meals are considered among the most promising feed materials in fish nutrition due to their sustainability and possibility of fish meal replacement. The present study is the first application of full-fat black soldier fly larvae (BSFL) meal in brown trout (Salmo trutta m. fario) diets. Two experiments were performed on 240 brown trout fingerlings (average body mass 4.85 g) distributed into four groups (12 tanks for the growth performance experiment, 10 fish/tank; and 12 metabolic tanks for the digestibility test, 10 fish/tank). The experimental group design was conducted as follows: control diet, with no BSFL and 35% fish meal, and experimental diets: BSFL5 – with 5% BSFL full-fat meal and 32.5% fish meal; BSFL10 – with 10% BSFL full-fat meal and 30% fish meal; and BSFL20 – with 20% BSFL full-fat meal and 25% fish meal. No effects were recorded in the case of growth performance and feed utilization parameters. The environmental sustainability of the usage of insect meals in fish diets was proven – due to the lower fish meal inclusion, the fish-in-fish-out ratio decreased by 31% in BSFL20. In the case of the viscerosomatic index, increases in BSFL5 and BSFL20 were reported. In all experimental groups, decreases in hepatosomatic index values were observed. Crude protein digestibility decreased in BSFL5 and BSFL20, while crude fat digestibility decreased only in the BSFL20 group. The effect of including BSFL full-fat meal in a brown trout diet on serum biochemical parameters was reported. The aspartate transaminase concentration increased in BSFL10 and BSFL20, while the gamma-glutamyl transpeptidase values decreased in BSFL20. In the case of total cholesterol, higher values were observed in BSFL10 and BSFL20. The albumin content decreased in the BSFL20 group, while globulin showed the highest values in the control group. The microbiota composition was not affected by insect meal inclusion. In conclusion, the results of the present study showed the high potential of BSFL full-fat meal application of up to 20% in a brown trout diet.     

Stocking rate and organic waste type affect development of three Chrysomya species and Lucilia sericata (Diptera: Calliphoridae): Implications for bioconversion

Fly larvae can be used effectively to reduce various organic waste types and produce value-added products, including protein as an ingredient in livestock feeds and oil for biodiesel production. However, fly development on different waste types may cause differences in growth rate and the body composition, which can further be influenced by fly species and their stocking rate. This study explored the impact of different waste types (kitchen waste, abattoir waste and swine manure) and larval stocking rate on growth and body composition of four blowfly species, Chrysomya chloropyga (Wiedemann), Chrysomya megacephala (Fabricius), Chrysomya putoria (Wiedemann) and Lucilia sericata (Meigen). First-instar larvae (20, 50 or 100), less than 3 hr old, were placed on 100 g of each waste type. Pre-pupal mass at commencement of post-feeding larval dispersal, time to onset of dispersal, survival and nutrient reserves were determined for each species, stocking rate and waste type. Our results revealed that larvae fed kitchen and abattoir waste had significantly higher dry mass, crude protein and lipid content compared with those fed swine manure. Higher survival rate was observed with increasing larval stocking rate. We provide important information to guide the mass production of high-quality nutrient-rich larvae and recommend C. putoria, which is versatile and effective on a range of waste products, as well as high in protein and lipids. The implications for waste management are discussed.     

Life history and cost analysis for continuous rearing of Podisus maculiventris (Say) (Heteroptera: Pentatomidae) on a zoophytophagous artificial diet

The impact of a zoophytophagous, insect-free artificial diet upon the developmental rate, life table parameters, and fertility table parameters was examined over 11 consecutive generations for domesticated and wild colonies of Podisus maculiventris (Say) (Heteroptera: Pentatomidae). This study showed that the developmental time, preoviposition period, fecundity, and nymphal survival improved in the domestic colony when fed an insect-free artificial diet for 11 consecutive generations, but remained relatively constant for the wild colony, as did reproductive rate and intrinsic rate of increase. Although, after 11 generations of adaptation to an artificial diet feeding regime, all reproductive and fertility table parameters were still significantly lower than when fed on T. ni larvae as the natural prey, the realized cost of rearing either colony on the artificial diet approached 1.2 times the cost of rearing these insects on a natural prey. This is a significant achievement in the effort to develop cost-effective artificial diets for the mass-rearing of beneficial pentatomids, and has positive implications for the use of one artificial diet to efficiently rear several beneficial insects.     

Relationship between adult and larval host plant selection and larval performance in the generalist moth, Trichoplusia ni

Adult oviposition preferences are expected to correlate with host plant suitability for the development of their offspring. For most lepidopteran species, this is particularly important as the hatching neonate larvae of many species are relatively immobile. Thus, the site of oviposition chosen by a female adult can greatly influence the probability of survival for her offspring. In the present study, we investigated the oviposition preference of adult Trichoplusia ni moths for six plant species to determine whether they could accurately rank the suitability of the plants for larval development. We also compared oviposition preferences to neonate larval acceptance and preference to determine whether the adult host range matched that of larval diet breath. Our results indicate that in two-choice and no-choice tests adult T. ni were able to rank the plants accurately, with the exception of anise hyssop. However, when given a choice of all six plants together, they laid more eggs on a plant that was not suitable for larval survival. Larvae accepted and fed on all plants in no-choice tests, and accurately ranked them according to larval performance. We conclude that neonate larvae are better able than adults to rank plants according to larval performance, and that larval diet breadth is wider than the range of plants accepted by adults. We also provide a discussion of the reduced accuracy of adult oviposition preference with increased plant choices.     

A new meatless diet for adult screwworm (Diptera: Calliphoridae)

Screwworm flies, Cochliomyia hominivorax (Coquerel), were fed on honey and spray dried egg product; honey, molasses, and spray dried egg product; honey and spray dried meat protein; as well as on a control diet of honey and horsemeat, which is the standard diet used for screwworm adult colony in the mass-rearing facility. In general, the weight of eggs laid by females fed on the diet of spray dried egg product was significantly higher than that laid by females fed on the standard horsemeat diet. Egg production declined when spray dried meat protein replaced the egg product. Partial replacement of honey with molasses in the egg diet did not decrease egg production, compared with the control diet. The use of spray dried egg diet has advantages over the horsemeat diet, such as storage, handling, preparation, feeding, and expense. A cost analysis suggests that replacing the horsemeat with spray dried egg product, and half of the honey with molasses, would reduce the cost of the diet by more than US $100,000 annually.     

Fertilizer affects the behaviour and performance of Plutella xylostella on brassicas

1 Foliar nitrogen concentration, which can be manipulated in crop plants by fertilizer supply, has long been recognized as a major factor in phytophagous insect abundance and performance. More recently, the type of fertilizer supplied has been shown to influence the abundance of some herbivore species. The diamondback moth Plutella xylostella is a global pest of Brassica crops. Although it has been the subject of numerous studies on host-plant resistance and pest control, few studies have addressed the effect of abiotic factors, such as nutrient supply, on its performance and behaviour.
2 We assessed oviposition preference, larval feeding preference and larval performance of P. xylostella on two cultivars of Brassica oleracea . Plants were grown using two fertilizer types, John Innes fertilizer and an organic animal manure, at high and low concentrations.
3  Plutella xylostella laid more eggs on cultivar Derby Day than Drago. Derby Day was also the cultivar on which larval performance was maximized. However, differences in larval performance between cultivars were only found when plants were grown in compost with John Innes fertilizer, and not when fertilized with animal manure.
4 Foliar nitrogen concentration was greater in plants grown in high fertilizer treatments but did not differ between cultivars. The concentrations of three glucosinolate compounds (glucoiberin, sinigrin and glucobrassicin) were greater in the high fertilizer treatments. Glucosinolate concentrations were higher in the Drago than the Derby Day cultivar.
5 These results are discussed in relation to the preference-performance hypothesis, and the assessment of plant resistance differences between cultivars using different types of fertilizer.     

A behavioral method for separation of house fly (Diptera: Muscidae) larvae from processed pig manure

A behavioral method applicable in biodegradation facilities for separation of house fly (Musca domestica L.) larvae from processed pig manure is presented. The method is based on placing a cover over the larval rearing tray, while escaping larvae are collected in collection trays. Separation units must be placed in a dark room to avoid negative phototactic responses of the larvae. After 24 h of separation, over 70% of the larvae escaped from processed manure and were collected in collection trays. Most of the larvae pupated within 48 h after separation. Mean weight of pupae recovered from manure residue was not significantly different from mean weight of pupae of separated individuals. Eclosion rate of pupae recovered from manure residue was significantly lower than eclosion of separated individuals, and was strongly related to separation success. Factors responsible for escape behavior of larvae are discussed.     

Advantages of a mixed diet: feeding on several foliar age classes increases the performance of a specialist insect herbivore

Two field studies were carried out to determine the influence of Abies balsamea foliage age on the preference and performance of larvae of Neodiprion abietis, a specialist Diprionid sawfly. Preference was determined by examining N. abietis defoliation on all age classes of foliage. Performance was estimated using larval survival, cocoon weights and the percentage of adults that were females. Neodiprion abietis preference for, and performance on, current-year foliage was very low, peaked on 2 or 3-year-old foliage, and declined on older foliage. Thus, sawfly feeding preference was adaptive. However, survival and cocoon weight were highest when sawflies were allowed to feed on all age classes of foliage, demonstrating that an insect specialist may perform better when feeding on several age classes of foliage from a single host plant species. These results indicate that either different larval instars have different nutritional requirements, or that food mixing provides the best diet, permitting the herbivore to obtain needed nutrients while avoiding ingestion of toxic doses of secondary metabolites. In addition, our results suggest that limited availability of varied foliage has more negative consequences for N. abietis females than for males, as the percentage of survivors that were females decreased when juvenile mortality was high. Our results emphasize the importance of considering non-linear changes in foliar quality as leaves age on herbivore preference and performance, and demonstrate how a herbivore can use this variability to maximize its fitness.     

Improvement in bioconversion efficiency and reduction of ammonia emission by introduction of fruit fermentation broth in a black soldier fly larvae and kitchen waste conversion system

The black soldier fly (BSF), Hermetia illucens (Diptera: Stratiomyidae), is an insect commonly used for the bioconversion of various organic wastes. Not only can the BSF convert organic waste into macromolecular organic substances, such as insect proteins, but it can also lessen the pollution associated with these waste products by reducing ammonia emissions, for example. In this study, we measured the effects of adding fruit fermentation broth (Fer) and commercial lactic acid bacteria fermentation broth (Em) to kitchen waste (KW), as deodorizing auxiliary substances, on the growth performance of black soldier fly larvae (BSFL), the intestinal flora structure of BSFL, the ammonia emission from the KW substrate, and the microbial community structure of the KW substrate. We found that the addition of Fer or Em increased the body weight of BSFL after 6 d of culture, increasing the growth rate by 9.96% and 7.96%, respectively. The addition of Fer not only reduced the pH of the KW substrate but also increased the relative abundance of probiotics, such as Lactobacillus, Lysinibacillus, and Vagococcus, which inhibited the growth of ammonifiers such as Bacillus, Oligella, Paenalcaligenes, Paenibacillus, Pseudogracilibacillus, and Pseudomonas, resulting in the reduction of ammonia emission in the KW substrate. Moreover, the addition of Fer or Em significantly increased the relative abundances of Bacteroides, Campylobacter, Dysgonomonas, Enterococcus, and Ignatzschineria in the gut of BSFL and increased the species diversity and richness in the KW substrate. Our findings provide a novel way to improve the conversion rate of organic waste and reduce the environmental pollution caused by BSF.     

A comparison of artificial diets for mass rearing Brontispa longissima (Coleoptera: Chrysomelidae) as hosts for the larval and the pupal parasitoids

The coconut hispine beetle, Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) is a serious pest of coconut palm. In this study, we developed an artificial diet for B. longissima so that the beetle could be used as a host for rearing two of its parasitoids, Asecodes hispinarum Boucek (Hymenoptera: Eulophidae) and Tetrastichus brontispae Ferrière (Hymenoptera: Eulophidae). The new artificial diet represents an improvement of our previous diet, which we used as a control. When beetle larvae were reared on the new diet, which contains cysteine but not cellulose powder and has twice as much coconut leaf powder as in the control, the adult emergence was 71% (approximately 2 times that in the control). We also examined the suitability of beetles fed on the new diet as hosts for the larval parasitoid A. hispinarum and the pupal parasitoid T. brontispae. The percentage of wasps that emerged from hosts that were fed the new diet was higher than that from the control-fed hosts. The new diet allowed both A. hispinarum and T. brontispae to produce adult wasps of the next generation, whereas the control only allowed T. brontispae to produce the next generation. These results suggest that the new diet is suitable for B. longissima and will facilitate mass-rearing of A. hispinarum and T. brontispae.     

Escaping an evolutionary trap: preference and performance of a native insect on an exotic invasive host

Exotic plants may act as population sinks or evolutionary traps for native herbivores. The native butterfly Pieris oleracea lays eggs on garlic mustard, Alliaria petiolata, but larvae develop very poorly on this exotic invasive plant. We examined oviposition preference of individual females and larval performance of their offspring for individuals from one area where garlic mustard is well established and one where it is absent. These data were used to assess whether garlic mustard is being incorporated into or excluded from the diet. Females from the area without garlic mustard showed a wide range of preference, families had low larval survival on garlic mustard, and larval survivorship showed no correlation with mothers’ preferences. Females from the area with garlic mustard preferred it to the native host, and larval survivorship on garlic mustard was positively correlated with the mother’s preference. Individuals surviving on garlic mustard took longer to pupate and weighed >30% less compared to pupae reared on normal hosts. Our results suggest that where garlic mustard is well established P. oleracea may be adapting to this plant by both improved larval performance and increased adult female oviposition preference for it.     

Dynamics of the intestinal bacterial community in black soldier fly larval guts and its influence on insect growth and development

Black soldier fly (BSF), Hermetia illucens (Diptera: Stratiomyidae), is a prominent insect for the bioconversion of various organic wastes. As a saprotrophic insect, the BSF inhabits microbe-rich environments. However, the influences of the intestinal microorganisms on BSF growth and development are not very clear. In this study, the dynamics of the intestinal bacterial community of BSF larvae (BSFL) were analyzed using pyrosequencing. Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria were the most prevalent bacterial phyla in the intestines of all larval instars. The dynamic changes in bacterial community compositions among different larval instars were striking at the genus level. Klebsiella, Clostridium, Providencia, and Dysgonomonas were the relatively most abundant bacteria in the 1st- to 4th-instar BSFL, respectively. Dysgonomonas and Providencia also dominated the 5th- and 6th-instar larvae, at ratios of 31.1% and 47.2%, respectively. In total, 148 bacterial strains affiliated with 20 genera were isolated on different media under aerobic and anaerobic conditions. Among them, 6 bacteria, BSF1–BSF6, were selected for further study. The inoculation of the 6 isolates independently into germ-free BSFL feeding on an artificial diet showed that all the bacteria, except BSF4, significantly promoted BSF growth and development compared with the germ-free control. Citrobacter, Dysgonomonas, Klebsiella, Ochrobactrum, and Providencia promoted BSF development significantly by increasing the weight gains of larvae and pupae, as well as increasing the prepupae and eclosion rates. In addition, Citrobacter, Klebsiella and Providencia shortened the BSF life cycle significantly. The results illustrate the promotive effects of intestinal bacteria on BSF growth and development.