4th Instars Research Articles

Effects on Growth of Ectropis grisescens Warren under Illumination

The 2nd and 5th instar of Ectropis grisescens Warren larvae were exposed to 400~405 nm illumination for 0, 60, 90, 120, 150 or 180 min to determine the effects of the irradiation on the development time as well as the rates of pupation, pupa emergence, aberration rate, eclosion rate, adult longevity and oviposition rate. The results showed that, as compared with control, as the processing time increases, the developmental duration was significantly shortened with 5 instar of E.grisescens Warren larvae. The eclosion rate and aberration rate were significantly increased. At the same time, the pupa weight was significantly higher than that of the 2nd instar larvae. The mortality increased significantly in 2nd of E.grisescens Warren larvae. There was no difference in adult eclosion rate between the two groups, and there was also no difference in the average oviposition. There was no significant difference between the two groups under 400~405 nm illumination, Male adults live longer than female adults.

FOOD CONSUMPTION AND NUTRITIONAL INDICES OF OAK TASAR WORM ANTHERAEA PROYLEI (JOLLY) FED ON QUERCUS GLAUCA

Studies were conducted under laboratory conditions to evaluate the food consumption and nutritional indices for the development of Antheraea proylei larvae fed on Quercus glauca. Larval duration was 5.4±0.489, 6.4±0.48, 7.2±0.4, 9.8±0.74 and 14.2±0.74 days in the 1st, 2nd, 3rd, 4th and 5th instars, respectively. Larvae consumed a total of 28.85 g insect– ¹ day– ¹, egested 4.164 g insect– ¹ day– ¹ and assimilated 24.69 g insect– ¹ day– ¹ of food provided. 82.3% of tissue growth was observed in the 4th and 5th instar larvae. Approximate digestibility (AD) decreased from 91.94% in the first instar larva to 80.79% in the 5th instar larva. Efficiency of conversion of digested food (ECD) into body tissue and efficiency of conversion of ingested food into growth (ECI) increased from 1st instar larva to 5th instar larva. The result obtained in the present study indicate that Q. glauca could serve as an alternate host plant for rearing A. proylei in areas where the main host plant Q. serrata is not found.

Biology of mustard aphid, Lipaphis erysimi on Brassica juncea genotype RH 725 in semi-arid zone of Haryana, India

Mustard aphid, Lipaphis erysimi (Kaltenbach) is one of the major insects of Indian mustard. It damages the various part of mustard plant as a result crop yield and oil content reduced. Scanning of the literature showed that no researcher had worked on all the parameters of biology of this insect on any crop. No work found regarding biology of mustard aphid on genotype RH 725. Therefore, on the basis of this fact studies on biology of mustard aphid was carried out during 2019-20 at Farmer’s field, Kolana village, Aravalli Hills Region, Rewari, Haryana, India. The results of the studies revealed that mustard aphid passed through four nymphal instars before attaining the adult stage. The average length of first, second, third and fourth instar nymph was 0.74 ± 0.07, 0.89 ± 0.06, 1.14 ± 0.14 and 1.31 ± 0.13 mm, respectively. The average width was 0.40 ± 0.04, 0.48 ± 0.03, 0.60 ± 0.06 and 0.72 ± 0.09 mm, respectively. The average length of apterate adult female was 1.62 ± 0.14 mm and width 0.94 ± 0.07 mm. The average duration of instars was 1.33 ± 0.37 (1st), 1.44 ± 0.38 (2nd), 1.79 ± 0.72 (3rd) and 2.14 ± 0.61 days of 4th instar. The average total nymphal instars period was 6.69 ± 1.11 days. The average longevity of adult recorded as 7.41 ± 1.61 days. The average pre-reproductive, reproductive and postreproductive period was 0.98 ± 0.47, 5.85 ± 1.58 and 0.57 ± 0.68 days, respectively. The average fecundity of an adult female was 24.63 ± 9.88 and birth rate was 4.12 ± 0.77 nymphs, whereas average total life span was 14.02 ± 2.21 days. This study provides important life history information of mustard aphid which may help to develop suitable integrated pest management strategies for this pest.

The functional response and predatory ability of the reduviid Coranus fuscipennis Reuter (Heteroptera: Reduviidae)) fed on the rice meal moth Corcyra cephalonica (Stainton)

The reduviid Coranus fuscipennis Reuter (Heteroptera: Reduviidae) is an important predator for biological control the pests of vegetables in Vietnam. The functional response of the 2nd, 3rd, 4th, 5th nymphal instars and adult male and female of the predator C. fuscipennis to the larvae of rice meal moth Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) was evaluated in laboratory conditions (temperature 30±2ºC; relative humidity 75±5%; and 14:10 h Light:Dark). The results show that the nymph and adult of C. fuscipennis responded to different densities of prey. They killed more number of prey at higher prey densities and less prey at lower prey densities that produced a curve linear type II functional response (Holling 1959). The maximum consumption was always found restricted when rearing the C. fuscipennis at high prey densities. The relationship between the predation rate of the C. fuscipennis and the prey densities was negative correlation (R is between 0.70 and 0.98), but between the number prey killed and the prey density is positive correlation. The searching time prey of the C. fuscipennis decreased when the prey densities increased that was confirmed by the negative correlation (R between 0.85 and 0.98). The reduviid C. fuscipennis bred by the C. cephalonica in laboratory and they can use for biological control some pests of vegetables (P rapae, S. litura and P. xylostella) in Vietnam.

Studies on biology of mango leaf webber Orthaga exvinacea (Hampson)

The laboratory studies on biology of mango leaf webber was conducted at the Department of Entomology, College of Horticulture, Bagalkot during 2018-19. The studies revealed that the mean preoviposition, oviposition and postoviposition periods lasted for 2.60±0.52, 4.10±0.74 and 1.90±0.74 days, respectively. The larva moulted six times by passing through seven larval instars. The mean durations of 1st, 2nd, 3rd, 4th, 5th, 6th and 7th instar were 4.80±0.92, 4.65±0.90, 4.41±0.63, 4.16±0.87, 4.52±0.51, 5.20±0.42 and 6.50±0.53 days, respectively with mean total larval period of 42.54±2.53 days. The mean duration of male and female pupal stage were 11.80±0.63 days and 14.30±1.43 days respectively. The mean longevity of adult male and female were 4.10±0.74 days and 5.80±0.42 days, respectively. The total life cycle completed in 58.44±3.90days in male and 62.64±4.59 days in female.

Spinosad ve Farklı Bacillus thuringiensis (Bacillaceae) Suşlarının Hyphantria cunea (Lepidoptera: Erebidae) Larvaları Üzerindeki Etkinliğinin Değerlendirilmesi

In this study, Bacillus thrungiensis aizawai Bonnefoi & de Barjac, 1963 (Florbac), different isolates of Bacillus thuringiensis (Bt) kurstaki Berliner, 1915 (Biobit, Delfin, Rapax, Rebound) and spinosad (Spintor) were assessed for their efficacy against different instars of Hyphantria cunea (Drury, 1773) (Lepidoptera: Erebidae) under laboratory and field conditions in 2019 in Duzce Province, Turkey. Spinosad was the most effective bioinsecticide, followed by Bt aizawai and Bt kurstaki isolates against various instars of H. cunea. In the laboratory, at 96 hour post-treatment, spinosad caused 98% mortality in 2nd and 3rd instars, and 83% mortality in 4th and 5th instars; Bt aizawai caused 98% mortality in 2nd and 3rd instars and 43% mortality in 4th and 5th instars; and Bt kurstaki isolates caused 95% mortality in 2nd and 3rd instars and 51% mortality in 4th and 5th instars. The results from the field study showed similar trends. The older instars were less susceptible to all the tested bioinsecticides than the younger instars, which may be attributable to the phenomenon known as “maturation immunity”. Bacillus thuringiensis kurstaki has already been recommended for management of this pest. Whereas the data indicated that spinosad and Bt aizawai could also be used as bioinsecticides for control H. cunea larvae.

Caste and age-related changes in circulatory hemocytes of honey bee, Apis mellifera anatolica (Hymenoptera: Apidae)

In recent years, there has been a great concern about increased honey bee losses and this phenomenon has turned into a global issue. Therefore, immune system research on honey bees gained importance. Hemocytes are an important part of the immune system. But there is a limited study about hemocyte types of honey bees. From this point of view, a detailed study was performed on hemocyte types of honey bee Apis mellifera anatolica was described in larval (3rd, 4th and 5th larval instars), prepupal, pupal, and adult stages of all castes including worker, drone, and queen. According to light microscopic examinations, prohemocyte, plasmatocyte, granulocyte, adipohemocyte and oenocytoid were determined in all castes. Prohemocytes are usually rounded cells with a large nucleus and small cytoplasmic area. Plasmatocytes are spherical or oval cells. Granulocytes are generally spherical cells with dense granules. Adipohemocytes are usually spherical cells having numerous lipid droplets within their cytoplasm. Oenocytoides are usually spherical cells with small and spherical nucleus centrally located. Also, we statistically compared the size of hemocyte types among these castes during metamorphosis. According to our measurements, the queen generally had the biggest hemocytes in comparison to the developmental stages in other castes. While statistically significant differences in the sizes of hemocyte types were mainly detected among castes of the pupal stage, there were no statistically significant differences in hemocyte sizes among castes of adult honey bees. In view of these findings, it may be stated that hemocyte profiles of A. m. anatolica vary based on the developmental stages of castes.

Diversity, Composition and Functional Inference of Gut Microbiota in Indian Cabbage white Pieris canidia (Lepidoptera: Pieridae).

We characterized the gut microbial composition and relative abundance of gut bacteria in the larvae and adults of Pieris canidia by 16S rRNA gene sequencing. The gut microbiota structure was similar across the life stages and sexes. The comparative functional analysis on P. canidia bacterial communities with PICRUSt showed the enrichment of several pathways including those for energy metabolism, immune system, digestive system, xenobiotics biodegradation, transport, cell growth and death. The parameters often used as a proxy of insect fitness (development time, pupation rate, emergence rate, adult survival rate and weight of 5th instars larvae) showed a significant difference between treatment group and untreated group and point to potential fitness advantages with the gut microbiomes in P. canidia. These data provide an overall view of the bacterial community across the life stages and sexes in P. canidia.

Histological investigation of the effects of fenoxycarb on neurosecretory cells in the silkworm, Bombyx mori brain.

Fenoxycarb 0-ethyl N-(2-(4-pheoxyphenoxy)-ethyl) carbamate is the most potent juvenile hormone analogue against a variety of insect species including the silkworm Bombyx mori. In this study, the effects of fenoxycarb on silkworm Bombyx mori brain neurosecretory cells in 5th instar were investigated. Fenoxycarb (1ng/10µl) was applied topically along the dorsa-medial line to the animals in the spinning behavior on day 1 of the experimental group. Brains removed by dissection were histologically examined by hematoxylin eosin (hem&eosin) and paraldehyde fuchsin staining. Three types of neurosecretory cells (NSCs) were identified, NSC-1, NSC-2 and NSC-3. It was determined that cell secretions were in different density on different days. It was shown that the secretion density of cells on different days was not the same as the experimental and control groups. The fenoxycarb was found to suppress the bombyxin (insulin-like peptides) secretion of cells in the spinning behavior on day 2. Also, it stimulated the division of NSCs on the spinning behavior on day 5.

Biological traits and life history of Pagiophloeus tsushimanus (Coleoptera: Curculionidae), a weevil pest on camphor trees in China

Cinnamomum camphora (L.) J. Presl. (Laurales: Lauraceae) is widely cultivated as an important landscape tree species in many urban areas in South China, especially in Shanghai City. Pagiophloeus tsushimanus Morimoto has become a destructive insect pest of C. camphora plantations in Shanghai, but the biological and ecological traits of this pest remain largely unknown. In this study, we investigated the damage and life history and determined the larval instar of P. tsushimanus. The results indicated that P. tsushimanus is a monophagous weevil pest, and C. camphora is the unique host tree species. C. camphora plantations in all administrative districts of Shanghai have been seriously damaged by P. tsushimanus. Adults often aggregate for feeding on the tender bark of twigs and occasionally on newly emerged buds. After experiencing damage, the twigs shrink and crack and the buds will shrink. Adults tend to repeatedly mate and oviposit, and all females lay single eggs at a time. Eggs will be covered with a mixture of secretions and wood chips by female adults. Larvae (1st–2nd instar) feed on the phloem, while 3rd–5th instar can bore into the phloem and the cambium. Massive tunnels, including three shapes (inverted “L”, inverted “T”, and inverted “Z”), were observed in the trunk of each tree, and resulted in swelling of the outer bark. P. tsushimanus has one life cycle per year in Shanghai. Both adults and larvae (3rd–5th instar) overwinter from early November to early April. Adults overwinter in grooves on the underside of branches or at branch nodes, and larvae overwinter in tunnels. Five larval instars of P. tsushimanus were determined according to Dyar's and Crosby's rules. The biological traits and life history of P. tsushimanus have been identified and can provide guidance in terms of pest control and plantation management.

Priprioca (Cyperus articulatus var. nodosus, Cyperaceae) Hydrolate as Larvicidal against Aedes aegypti

Dengue cases have grown significantly in Brazil in recent years. Studies with plant extracts show the insecticidal potential of bioactive substances that become candidates for future commercial products. This work evaluated the larvicidal effect of essential oil, without hydrolysis of Cyperus articulatus var. nodosus against the third and fourth wide stage of Aedes aegypti, which reduces larvae survival by as much as the 3th and 4th instar of Ae. aegypti. A chemical characterization of the hydrogen skeletons was performed by the GC-MS, revealing verbenone (%), trans-sabinol (%) and mirtenol (%) as major compounds.

Influence of Aquatain™, a monomolecular surface film on surface tension for controlling the filarial vector Culex pipiens (Diptera: Culicidae)

Surface tension is a phenomenon in the liquid media and plays an important part in the development and survival of aquatic animals. Influence of Aquatain™ monomolecular film on surface tension was determined against mosquito larvae and pupae at different temperatures (10, 15, 20, 25, 30 and 35 °C) and Aquatain™ doses (0.5, 1.0 and 2.0 ml/m2). In the laboratory, Aquatain™ showed larvicidal and pupicidal effects against the filarial vector Culex pipiens. Higher mortality was observed in late and more weighted instars/stages than young ones as well as in the pupal stage. The pupal mortality reached 76.2%, 86% and 93.3% after 12 h post-treatment at 0.5, 1.0 and 2.0 ml/m2, respectively, and it was completely eliminated (100%) within 24 h compared to 15.1%, 26.9% and 38.2% for 1st larval instar, respectively. Also, results showed at 0.5 ml/m2 with temperature range: 10, 15, 20, 25, 30 and 35 °C, the mortality reached 4.0, 6.7, 10.8, 17.3, 22.7, 29.3% and 32, 44, 54, 72, 84, 97.3% for 1st and 4th larval instar, respectively, where the surface tension (γ) was 65.6, 62.4, 58.0, 57.0, 54.2 and, 49.6 dyn/cm, while the Aquatain™ was more effective on mosquito larvae and pupae at high doses with the temperature range. On the other hand, without Aquatain™ dose, the mortality value ranged between 0.0 - 1.2%, and the surface tension (γ) was 74.5 dyne/cm, which is considered as an accidental death. Aquatain™ was effective against all aquatic phases of mosquitoes, especially against the last and weighted ones. Not only was the efficacy of Aquatain™ increased by increasing the dose, but it also increased with the increased temperature of the environment. This efficiency of Aquatain™ is due to its ability to reduce the surface tension of the water medium, preventing different stages of mosquitoes from reaching the surface for breathing thereby leading to suffocation and death. Therefore, we recommended Aquatain™ in programmes for mosquito control and other aquatic insects as a safe, cost-effective control agent.

Role of Bm30kc6 gene in cell apoptosis and thesilk gland degradation signaling pathway in Bombyx mori L.

Apoptosis is a process of programmed cell death that is regulated by genes independently. TheBm30kc6 gene is a kind of small molecular lipoprotein about 30 kDa, expressed highly in the late stage of the silkworm hemolymph. Our study showed that overexpression of Bm30kc6 could decrease caspase-3 activation. Meanwhile, activation of caspase-3 increased when Bm30kc6 expression was disturbed by small interfering RNA (siRNA). Cell apoptosis was decreased when Bm30kc6 was overexpressed under UV treatment. The apoptosis rate induced by actinomycin D is similar to the trend by UV. It was inferred that Bm30kc6 has an inhibitory effect on the apoptosis of silkworm cells. The apoptosis-related genes, such as BmFadd, BmDredd, and BmDaxx were increased after overexpression of Bm30kc6or decreased after interference of siRNA. It was speculated that there was an interactiverelationship between Bm30kc6, BmDaxx, BmFadd, and BmDredd in the apoptosis signaling pathways. We investigated the transcription expression of theBm30kc6 gene in different growth stages and tissues of the silkworm. The results showed that Bm30kc6 reached its peak in the hemolymph during the 6th to 7th days of the5th instar, or in spinning post 24 h of the silk gland. In the silkworm BmN cells treated with caspase-3/7 inhibitor, the caspase-3 enzyme activity, and the expression levels of Bm30kc6, BmFadd, BmDredd, and BmDaxx were significantly reduced. The expression levels of Bm30kc6 increased sharply when silkworms were treated by molting hormone at Day 3 or 5 of the 5th instar. The results indicated that the expression of theBm30kc6 gene was affected by the molting hormone and was likely to be its downstream target. In conclusion, the results suggest that theBm30kc6 gene is involved in the regulation of the apoptotic signaling pathway and plays a role in the apoptotic process.

Life history aspects of the buthid scorpion Tityus forcipula (Gervais, 1843) with remarks on its thermal limits

Observations on the entire life history of scorpion species are uncommon, and these studies primarily focus on postembryonic development. So far, little is known on how changes in temperature or humidity could affect communities of scorpions. Here, we present data on the embryonic and postembryonic development of Tityus forcipula (Gervais, 1843), a scorpion living in the Colombian Central Cordillera that was subjected to different climate regimes. For a comparative approach, one group was raised under lower conditions (23–24°C) and another group was raised under higher temperatures (25–27°C, meaning a 2–3°C increase). Our results clearly demonstrate that T. forcipule reared under laboratory conditions is not able to thrive under constant higher temperatures. A minority of the latter group (< 10%) reached adulthood, but never reproduced. Of the 43 specimens kept under lower temperatures (with a mild diapause), 21 females and 19 males reached maturity in the 5th instar; only one female and two males required an extra molt to mature. Tityus forcipula specimens reached maturity after 463 days of postembryonic development. The average for embryonic development was 208 days, with an average of 12 neonates per litter. Twenty-four different morphometric measurements were taken from all specimens for each exuvium of the juveniles and the adult stage. The results indicated a relationship, albeit partly poorly developed, between the sexes, in several measured structures and the instars.

English

Mosquitoes are the major health threat as they transmit plasmodium parasites that cause malaria. Since mosquitoes developed resistances towards insecticides, investigators are searching for alternative control measures. Bioactive plant chemicals have been identified to serve as a defense mechanism against insects’ larvae. Therefore, the aim of the study was to evaluate larvicidal activities of Juniperus procera extracts in in vitro against 3rd to 4th instars larvae of Anopheles arabiensis. The leaves of the plant were collected from Fogera District and brought to Bahir Dar University where it was extracted with chloroform, petroleum ether, ethanol and acetone. The phytochemical screening was performed. A. arabiensis 3rd to 4th instar larvae were collected from Woreta town of Fogera District and bioassay was tested on 20 larvae at room temperature. Finally, the percentage mortality of larvae at 24, 48 and 72 h was calculated. The result showed that chloroform, petroleum ether, acetone and ethanol extracts of J. procera caused significant mortality of anopheles mosquito larvae (P=0.00). The mortality rate increased with the concentration of the extracts. Therefore, the study concluded that J. procera might be an alternative in mosquito control. Key words: Anopheles arabiensis, Juniperus procera, Larvicidal activity, plant extract, solvent.

Estudo comparativo de bioinseticidas a base de Metarhizium anisopliae (Ascomycota: Clavicipitaceae) no controle de Mahanarva fimbriolata (Hemiptera: Cercopidae)

A cigarrinha-das-raízes Mahanarva fimbriolata é uma das principais pragas em cana-de-açúcar e tem causado sérios prejuízos. Objetivou-se avaliar a patogenicidade de diferentes bioinseticidas à base do fungo entomopatogênico Metarhizium anisopliae sobre ninfas de cigarrinhas. Cinco ninfas de 4º instar foram colocadas em placas de Petri contendo folha de cana higienizada. Os bioinseticidas Metarriz®; Metarril®; M. anisopliae JCO®; Metiê® e Gr-Inn CE® foram aplicados sobre as ninfas e folhas de cana com pressão de 15 libras.pol-2 e mantidas à temperatura de 25±1 °C, UR de 70±10% e fotofase de 12h. Foram calculadas a mortalidade acumulada, mortalidade corrigida pela fórmula de Abbott para o 3º dia após pulverização e submetidas à análise de variância pelo teste F, Tukey a P ≤ 0,05, e TL50 (tempo letal). Os bioinseticidas Metarril®, Metarriz® e Gr-Inn CE® apresentaram 91,7, 87,5 e 84,2% de mortalidade corrigida e 93,3, 90,0 e 86,7% de mortalidade acumulada. O bioinseticida Metarriz® apresentou a maior mortalidade com menor TL50 (0,9 dias) no primeiro dia, no segundo dia o Metarriz® e Metarril® obtiveram mortalidades de 86,7 e 80%, respectivamente. No terceiro, quarto e quinto dia os bioinseticidas apresentaram patogenicidade acima de 70%.

Eco-friendly secondary metabolites from Conyza dioscoridis against Spodoptera littoralis

Spodoptera littoralis (Boisd.), is one of the most dangerous pests in Egypt, targeting many economically crucial crops. In addition, population growth is major challenge to agricultural production. The aim of the current study is evaluation of insecticidal properties of chloroform/ methanol extract prepared from Conyza dioscoridis aerial part as well as study the biochemical changes on the 4thlarval instars of the cotton leaf worm, S. littoralis under laboratory conditions. Moreover, the bioactive secondary metabolites were isolated from the tested extract by chromatographic techniques and identified using spectroscopic analysis. Also, the volatile constituents distilled from Conyza dioscoridis aerial parts were characterized by GC/MS analysis. Column chromatography of bioactive chloroform/ methanol extract led to the identification of five major compounds including three triterpenes; β-amyrin-3-acetate, β-lupeol-3-acetate, β-amyrenone along with dotriacontane hydrocarbon as well as one methoxyflavone; 5,4ʹ-dihydroxy-6,7-dimethoxyflavone. Insight on insecticidal efficacy, the percentage of cumulative mortalities during pupal and adult stages reached to 76.6% and 83.3%, respectively after feeding 4thlarval instars of S. littoralis on tested extract with insecticidal activity in a dose-dependent manner. Whereas, β-amyrenone, lupeol acetate and 5,4ʹ-dihydroxy-6,7-dimethoxyflavone suppressed 50, 60 and 73.3% of 4th instar larvae of S. littoralis at concentration 0.3, 0.5 and 0.5%, respectively. Also, the extract showed marked decreasing in acetyl cholinesterase activity, total lipids and protein contents. The GC/MS analysis of volatile oil of C. dioscoridis aerial part led to the identification of 63 sensory metabolites that represent 93.68% of total volatile constituents. The oil was characterized by a high percentage of oxygenated sesquiterpenes (36.00%) and sesquiterpene hydrocarbons (21.09%), in addition phenylated and aliphatic hydrocarbons (15.43% and 14.58%, respectively). α-Cadinol was the major component (8.47%) accompanied by a high percentage of sesquiterpene alcohols. C. dioscoridis aerial part is a promising botanical pesticide with different mechanisms of action targeting 4th instars of larvae of S. littoralis. It had adverse effects survival, fecundity, oviposition, pupae and adults development and also acts as metabolic and acetylcholine esterase inhibitors against S. littoralis. So, the present findings may encourage more applied researches to evaluate crude extract and/or tested compounds in semi-field and field trial for controlling S. littoralis.

Effect of Garlic and Lemongrass Essential Oils on Some Biological and Biochemical Aspects of Corn Stem Borer Sesamia cretica Larvae (Lepidoptera: Noctuidae) During Diapausing Phase

The toxicity of two essential oils garlic and lemongrass were tested against diapausing destined larvae of the corn stem borer Sesamia cretica (Led.). Some biological aspects of garlic and lemongrass oils were evaluated on 2nd and the last (6th) instar diapausing destined larvae by dipping (feeding) method. Garlic and lemongrass oils were topically applied on the dorsum of diapausing 6th larval instar for 72 h to evaluate their toxicity on the total nutrient contents (proteins, lipids, and carbohydrates) and compared to that found in the control. The two oils had a significant reduction effect on larval duration and larval weight leading to increase the percentage of larval mortality. When the newly ecdysed last instar diapause-destined larvae of S. cretica treated with garlic oil at the concentration LC50, they had induced to undergo up to 2 stationary larval moulting expressed in (50%), while lemongrass oil has proved to be more efficient in inducing larvae to undergo up to 3 stationary larval moults (92.3%). Death as expressed in the mortality % had occurred mostly in the larval instar or in rare cases as larval–pupal intermediate after surviving as such up to 1–2 months. Our results show that lemongrass oil had no effect on total protein and lipid contents of treated larvae, while garlic oil increased total protein. Carbohydrates serve as the labile energy source of these larvae and may be converted to lipids for storage. It seems that the observed disturbance of nutrient content during diapause stage and may be key element in induction and termination of facultative diapause of S. cretica. The total carbohydrates content reduced significantly in diapausing larvae treated with the two oils. The results of this study demonstrated that essential oils of garlic and lemongrass have significant toxic effects on certain biological and biochemical parameters of S. cretica through breaking the diapause stage, and could be helpful in further research for practical control of this insect pest.

Transcriptome and proteomics-based analysis to investigate the regulatory mechanism of silk gland differences between reciprocal cross silkworm, Bombyx mori

• The heterosis of the orthogonal group was higher than that of reverse cross group. • Proteomics and transcriptomics analysis of the reciprocal cross silkworm. • Six DEGs and DEPs between the reciprocal cross silkworms were validated by qRT-PCR. • Serpin-32 expression may cause silk gland difference between reciprocal silkworms. The silkworm, Bombyx mori , is an important model economic insect. Cross breeding is an important way to select excellent silkworm varieties, and different combinations among the same parents often show different genetic characters. To explore the regulatory mechanism of silk gland differences in reciprocal cross silkworm, the 3rd day of the 5th instar of the orthogonal silkworm (306♀ × NB♂, 798♀ × NB♂) and the reverse cross silkworm (NB♀ × 306♂, NB♀ × 798♂) silk glands were used as experimental materials, then using Label-free-based proteomics and RNA-Seq-based transcriptomics for analysis. Besides, the qRT-PCR was used to validate the expression of differentially expressed genes. The results showed that in NB♀ × 306♂ VS 306♀ × NB♂ group, 280 differentially expressed genes and 238 differential proteins were up-regulated while 40 differentially expressed genes and 149 differential proteins were down-regulated; in NB♀ × 798♂ VS 798♀ × NB♂, 82 differentially expressed genes and 325 differential proteins were up-regulated while 113 differentially expressed genes and 258 differential proteins were down-regulated. Further analysis indicated that the up-regulation of mitochondrial aldehyde dehydrogenase gene and cytochrome P450 gene, which are related to mitochondria, might be regulated by maternal inheritance. The GO and KEGG enrichment initially showed that the differential genes and proteins are mainly involved in processes such as protease metabolism, ATP hydrolysis, lipid transport, insect hormone synthesis, and TCA cycle. The down-regulated expression of ecdysone oxidase and Serpin-32 in the reverse cross group will reduce the energy utilization in the process of silk gland synthesis, increase the hydrolysis of serine, affect the synthesis and transport of silk protein, and cause the difference between reciprocal crosses.

Biology and Predatory Potential of the Eleven Spotted Coccinellid Predator Coccinella undecimpunctata L. (Coleoptera: Coccinellidae) reared on two Aphid Species (Hemiptera: Aphididae) under Laboratory Conditions.

The coccinellid predator Coccinella undecimpunctata is considered one of the most efficient and potential predators of many soft bodied insect pests especially aphids. The biology and predatory potential of this coccinellid were studied on the 4th nymphal instar of two aphid species, Aphis craccivora Koch. and Schizaphis graminum (Rondani). By rearing on A. craccivora at 20, 25 and 30°C the incubation periods of C. undecimpunctata eggs were 5.84, 4.32 and 3.62 days, led subsequently, to 80.20%, 94.40% and 64.40% hatching, respectively, opposed to 5.98, 4.60 and 3.42 days with 74.40, 90.40 and 62.00% hatchability when rearing took place on S. graminum. The total larval duration lasted 9.96 days on A. craccivora, being, significantly, shorter than the 10.67 days resulted from rearing on S. graminum. Throughout the whole period of the larval stage feeding on the 4th instar nymphs of A. craccivora and S. graminum, a single larva fed on163.54 or 170.21 nymphs, respectively. C. undecimpunctata female's longevity elapsed 64.04 and 63.19 days, respectively. A single mated female deposited 686.69 eggs when reared on A. craccivora, opposed to 590.57 eggs by feeding on S. graminum. These results concluded that rearing of C. undecimpunctata on A. craccivora proved the best to obtain immature stages of shorter durations, much lower consumption and the highest reproductivety of eggs.