Egg Incubation Period Research Articles

Biology of the Endemic Endangered Swallowtail Butterfly, Papilio desmondi teita (Lepidoptera: Papilionidae), on Wild Citrus Species in Taita Hills, Kenya

The Taita Hills swallowtail butterfly, Papilio desmondi teita, was reared in captivity on wild citrus (Rutaceae), Toddalia asiatica and Clausena anisata, in Ngangao Forest, Taita Hills, Kenya. The butterflies were exposed to the host plants for oviposition inside the laying buckets under ambient laboratory conditions. Results revealed that P. desmondi teita could only complete development on T. asiatica and but not on C. anisata in both seasons. The egg incubation period on T. asiatica was significantly shorter ( P < 0.001) compared to C. anisata during the first season ( P = 0.595) but not in the second season. The development period of the butterfly in 1st and 2nd seasons on T. asiatica was 81.13 ± 0.44 days and 112.15 ± 1.20 days, respectively, while a female-biased sex ratio was observed in the first and second seasons. Findings from this study indicate that T. asiatica was the most suitable host plant for development of P. desmondi teita.

Biology and integrative taxonomy of leaf folder, Helcystogramma hibisci (Stainton, 1859): a pest of musk mallow, Abelmoschus moschatus (L.) Medik.

Abstract The leaf folder, Helcystogramma hibisci (Stainton, 1859) (Lepidoptera: Gelechiidae) is an oligophagous pest of different malvaceous plants. In this study, attempts have been made to study the biology and taxonomy of the insect infesting musk mallow (Abelmoschus moschatus), an aromatic cum medicinal plant in India, following an integrative approach based on external morphology, internal genitalia structures, and molecular taxonomy. In the initial stage, the larva scrapes the tender surface of the leaves, and later, grown-up larvae web the leaves by folding them longitudinally. The entire inner content of the leaves is eaten by the larvae and ultimately the leaves get dry. The identity of the pest species is confirmed through dissecting of the male and female genitalia of the pest species and molecular confirmation (GenBank accession number ON545806). By studying the biology of the insect, the egg incubation period, larval period, and pupal period were determined to be 4.70 ± 0.64, 13.66 ± 0.86, and 6.46 ± 0.61 (male), and 7.60 ± 0.71 days (female), respectively. The average fecundity and adult longevity of males and females were 61.20 ± 11.68 eggs/female, 4.93 ± 1.38 days (male), and 8.06 ± 1.56 days (female), respectively. During their fourth instar, male larvae have dark-colored gonads that are easily visible on the dorsal integument of the abdominal segment distinguishing them from female larvae. Further confirmation of the identification was done by keeping the larvae in separate vials until emergence; larvae with this dark-colored character could be confirmed to be males, while other the larvae developed into female moths. The head capsule width of the larval instars was 0.26 ± 0.02, 0.47 ± 0.04, 0.66 ± 0.03, 0.83 ± 0.06, and 1.13 ± 0.14 mm, respectively. The information is useful for proper identification and management of this pest in such a valuable and popular plant as musk mallow in India. To our best knowledge, this is the first description of this pest species from the Indian region along with molecular confirmation.

Saffron Bulb Mite Rhizoglyphus robini (Claparede) Its Occurrence, Biology and Chemical Intervention Tactics on Saffron Corms in Kashmir, India

Saffron corms are attacked by a wide variety of arthropod pest species and mites are one of them. Among Arachnida class bulb mite causes considerable damage to saffron crop and presence of this pest is a regular feature in its cultivation. To record the occurrence of saffron bulb mite, field study was conducted at different saffron growing areas of Kashmir. For biology of the pest, laboratory study was conducted at Department of Entomology, Faculty of Horticulture, Sher-e-Kashmir University of Agricultural Sciences and Technology, Shalimar. The mean percent infestation of saffron bulb mite from all the locations revealed highest and lowest percent mite infestation of 25.83 and 12.50 recorded from Dhussu and Saffron research station respectively. Passing through five active stages viz., Egg, Larva, Protonymph, Tritonymph and adult completed the life cycle of Rhizoglyphus robini. The heteromorphic deutonymph or hypopal stage is sometimes produced for phoresis when population is overcrowded, but this stage was not observed during the study. The results revealed that the females laid their eggs on the corms. The average incubation period of egg was observed to be of 6.16 ±0.78 days while as other developmental periods Larva, Protonymph, and Tritonymph were of 5.22 ±0.68, 5.76 ±0.52, and 7.00 ±0.91 days at 25± 50C respectively. The longevity of adult male and female were 27.9 ±0.44 and 22.9 ±0.69 days respectively. The efficacy of different doses of acaricides against Saffron bulb mite revealed that drenching the soil with chlorpyrifos 20 EC + foliar spray with cyenopyrafen 30 SC showed best results with 4.23 percent leaves with stunted growth and chlorosis, 97.34 percent flower emergence and 2.23 percent bulb rot.

Quantifying Environmental Flow in the Form of Pulse Flow for Fish Protection

Pulse flow, which includes base flow, peak flow, flow duration, occurrence time, and frequency, is a manifestation of environmental flow in rivers. This paper describes a methodological framework for determining pulse flow based on an analysis of fish spawning behavior and presents its application to the second Songhua River in northeastern China. Peak flow was determined based on the hydrographic-habitat relationship for fish spawning in conjunction with physical habitat simulation. The flow duration was determined based on the incubation period of fish eggs. The occurrence time and frequency were determined based on the suitable temperature for fish spawning. This application differs from conventional methods for dividing fish spawning periods and selecting target species in the corresponding period. Fish were divided into cold-water fish, hypothermal-water fish, and warm-water fish according to spawning temperature, and the target species in each month of the spawning period (April to July) were identified. For the same spawning period, the hydrographic-habitat relationships of target species with adhesive and drifting eggs were weighted to determine the peak flow. The most suitable peak flow for fish spawning from April to May in the research region is 900 m3/s and 1200 m3/s for June to July. Using the proposed framework, an ecological hydrograph from April to July was obtained by combining the method of pulse flow with habitat simulation. Fifteen days, eight days, and five days were chosen as the flow durations for April, May, and June to July, respectively. We recommend scheduling two high pulse flows each month from May to July while limiting the occurrence to only one in April. The results show that this framework offers a promising approach for developing environmental flows in rivers with a variety of fish species.

DEVELOPMENTAL PARAMETERS OF TRILOCHAVARIANS (LEPIDOPTERA: BOMBYCIDAE); A PEST OF WEEPING FIG, FICUSBENJAMINA IN PAKISTAN

The developmental parameters of Trilochavarianswere studied on weeping fig, Ficusbenjamina at 26°C ± 1.0 temperature and 65±5% relative humidity. The study showed that female laid 160-270 eggs in 2-6 layers on the dorsal side of the leaves. Some unmated female also laid 15-183 eggs in groups which never developed into larvae. 24 hours prior to hatching, the eggs turned black. Egg incubation period was 3.46±1.22 days on F. benjamina. The high fecundity increased the survival rate of T. varians.There were five larval instars which recorded in this study period. Last two instars caused more damage due to resemblance to hosts parts such as bark. There was a short, fleshy horn on the ninth abdominal segment. The developmental time of first, second, third, fourth and fifth larval instars was 2.44±0.82, 3.56±0.53, 3.72±0.26, 4.54±0.79 and 6.20±0.78 days, respectively. Boat shaped and yellow silken pupation was usually observed. The male and female mean longevity was 6.0 ± 1.171 and 11.4 ± 1.70 days. The dorsal side of the female forewings had pale reddish brown lines. The thorax, head, and abdomen of the female had darker reddish brown coloring than those of the male. Adult hind wings had reddish brown outer edges and were grayish in color. The average lifespan for male and female was 6.23±2.09 and 10.01±0.99 days, respectively. Thecurrent paper will lead to proper management practices for this pest

Lack of fitness costs in dsRNA-resistant Leptinotarsa decemlineata ([Coleoptera]: [Chrysomelidae]).

The Colorado potato beetle, Leptinotarsa decemlineata (Say) ([Coleoptera]: [Chrysomelidae]), is the most important defoliator of solanaceous plants worldwide. This insect displays a notorious ability in adapting to biological and synthetic insecticides, although in some cases this adaptation carries relevant fitness costs. Insecticidal gene silencing by RNA interference is a novel mode of action pesticide against L. decemlineata that is activated by ingestion of a double stranded RNA (dsRNA) targeting a vital L. decemlineata gene. We previously reported laboratory selection of a > 11,000-fold resistant strain of L. decemlineata to a dsRNA delivered topically to potato leaves. In this work, we tested the existence of fitness costs in this dsRNA-resistant colony by comparing biological parameters to the parental strain and an additional susceptible reference strain. Biological parameters included length of egg incubation period, number of eggs per clutch, egg viability, larval viability, length of larval and pupal periods, adult emergence, number of eggs laid per day, sex ratio, and adult longevity. Comparisons between the 3 beetle strains detected no fitness costs associated with resistance to dsRNA. This information is important to guide effective insect resistance management plans for dsRNA insecticides against L. decemlineata applied topically to potato leaves.

Dietary zinc supplementation in breeding pigeons improves the carcass traits of squabs through regulating antioxidant capacity and myogenic regulatory factor expression

The purpose of this experiment was to explore the effects of zinc supplementation in breeding pigeons diet on carcass traits, meat quality, antioxidant capacity and mRNA expressions of myogenic regulatory factors of squabs. A total of 120 healthy White King pigeons were randomly assigned to 5 treatments, each involving 8 replicates. The experiment lasted for 46 d (18-d incubation period of eggs and 28-d growth period of squabs). The 5 groups were 0, 30, 60, 90, and 120 mg/kg zinc addition. Results showed that the 28-d body weight, breast muscle yield, zinc content in crop milk and myogenic factor 6 (MyF6) abundance of breast muscle were linearly increased (P < 0.050), but the abdominal fat yield linearly decreased (P=0.040) with increasing dietary zinc supplementation. Both the linear (P < 0.050) and quadratic responses (P < 0.001) were observed in copper zinc superoxide dismutase (Cu-Zn SOD), total antioxidant capacity (T-AOC) and malondialdehyde (MDA) contents in liver and breast muscle. The 28-d body weight was increased by 90 mg/kg zinc supplementation (P < 0.05), and there is no significant difference between 90 and 120 mg/kg zinc addition. The breast muscle yield, Cu-Zn SOD and T-AOC contents in breast muscle and liver, zinc contents in crop milk and breast muscle, MyF6 mRNA expression in breast muscle were higher (P < 0.05) in the group supplemented with 120 mg/kg zinc than the control. The abdominal fat yield was numerically lowest, and MDA contents in breast muscle and liver were significantly lowest in the group fed 120 mg/kg zinc (P < 0.05). However, the meat quality traits were not affected (P > 0.05) by zinc supplementation, except for shear force. It should be stated dietary zinc supplementation at the level of 120 mg/kg for breeding pigeons increased body weight and breast muscle yield of squabs, which may be associated with the up-regulating MyF6 mRNA expression and antioxidant capacity in liver and breast muscle.

Basic Developmental Characteristics of the Fall Armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), Reared under Laboratory Conditions

The life cycle of the invasive alien insect pest, fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), was studied using a colony established from field-collected larvae. Eggs, neonate larvae, and newly emerged adult moths were used in experiments to investigate the basic biology of the FAW. Adult females laid up to 1184 eggs with a mean of 469 ± 22 eggs per female. The incubation period of eggs and percentage hatchability were 2-3 days and 80–87%, respectively. The mean larval lengths from the first to the sixth instar were 4.63, 6.60, 9.76, 15.86, 25.13, and 27.81 mm, respectively. The mean larval weights were 0.003, 0.019, 0.045, 0.050, 0.060, and 0.067 g, respectively, for the six instars. The mean width of the head capsule of the sixth instar larva was 2.76 mm. The total larval duration throughout the six instar stages was 16–18 days, while the mean pupal weight was 0.25 ± 0.001 g and 0.35 ± 0.011 g for males and females, respectively. The mean pupal length was 14.3 ± 0.16 mm for males and 17.2 ± 0.14 mm for females. Pupal duration ranged from 8 to 14 days, with a mean of 10.35 ± 0.26 days, while the pupal emergence rate ranged from 60 to 94%, with a mean of 80.25 ± 1.28%. The life cycle of males lasted 33–44 days and that of females lasted 36–49 days under laboratory conditions. Adult copulation occurred between 8 and 11 pm, with the peak occurring at 9 pm. This study provides baseline information about the biology of the FAW. Apart from being an important reference point for future research on the FAW, the data provided would aid FAW management decision-making.

Preliminary Study on Artificial versus Animal-Based Feeding Systems for Amblyomma Ticks (Acari: Ixodidae).

Hard ticks pose a threat to animal and human health. Active life stages need to feed on a vertebrate host in order to complete their life cycle. To study processes such as tick-pathogen interactions or drug efficacy and pharmacokinetics, it is necessary to maintain tick colonies under defined laboratory conditions, typically using laboratory animals. The aim of this study was to test a membrane-based artificial feeding system (AFS) applicable for Amblyomma ticks using Amblyomma tonelliae as a biological model. Adult ticks from a laboratory colony were fed in a membrane-based AFS. For comparison, other A. tonelliae adults were fed on calf and rabbit. The proportions of attached (AFS: 76%; calf/rabbit: 100%) and engorged females (AFS: 47.4%; calf/rabbit: 100%) in the AFS were significantly lower compared to animal-based feeding (p = 0.0265). The engorgement weight of in vitro fed ticks (x¯ = 658 mg; SD ± 259.80) did not significantly differ from that of ticks fed on animals (p = 0.3272, respectively 0.0947). The proportion of females that oviposited was 100% for all three feeding methods. However, the incubation period of eggs (x¯ = 54 days; SD ± 7) was longer in the AFS compared to conventional animal-based feeding (p = 0.0014); x¯ = 45 days; SD ± 2 in the rabbit and (p = 0.0144). x¯ = 48 days; SD ± 2 in the calf). Egg cluster hatching (x¯ = 41%; SD ± 44.82) was lower in the AFS than in the other feeding methods (rabbit: x¯ = 74%; SD ± 20; p = 0.0529; calf: x¯ = 81%; SD ± 22; p = 0.0256). Although the attachment, development, and the hatching of AFS ticks were below those from animal-based feeding, the method may be useful in future experiments. Nevertheless, further experiments with a higher number of tick specimens (including immature life stages) and different attractant stimuli are required to confirm the preliminary results of this study and to evaluate the applicability of AFS for Amblyomma ticks as an alternative to animal-based feeding methods.

«Unfaithful» Pink salmon. Random or regularity?

The reasons of «failed» forecasts for catch of pink salmon at the mainland coast of the Tatar Strait are analyzed. The classical «stock–recruitment» models produce regular errors in the forecasts of runs of pacific salmon under changing conditions of reproduction. To reduce the prediction errors, these models should include parameters of meteorological conditions in the freshwater period of salmon life. In particular case of pink salmon in the Tatar Strait, a relationship is revealed between the year-class strength and precipitation in winter during the period of egg incubation. Including this factor to the model based on Ricker equation increases the proportion of certainty in the variance of recruitment by more than 30 %.

The Parasitic Potential of Bracon brevicornis Wesmael and Chelonus blackburni (Cameron) (Hymenoptera: Braconidae) on the Age of Earias vittella (Fabricius) (Lepidoptera: Nolidae) and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in Laboratory Conditions

Aims: The current study was carried out to investigate the parasitic potential of density of two important parasitoids against the age of two important bhendi fruit borer pests.&#x0D; Study Design: Completely Random Design (CRD).&#x0D; Place and Duration of Study: The study was conducted during 2019-20 and 2020-21 at bio control laboratory of National Bureau of Agricultural Insect Resources (ICAR) Hebbal, Bengaluru (Latitude: 13.097221 Longitude: 77.568291) by adopting standard methodology and materials.&#x0D; Methodology: An experiment was designed to examine the effects of parasitoid densities of Bracon brevicornis and Chelonus blackburni on the host age (different instars) larvae of fruit borers two important fruit borers by checking the the percent parasitization. The second, third, and fourth instar larvae of E. vittella were introduced separately at different ratios of Bracon brevicornis parasitoids and host viz., 1:10, 2:10, 3:10, 4:10, and 5:10. Mated female parasitoids were utilised in all cases, and the experiment was carried out in a glass jar of 18 x 12 cm, using the sandwich approach. [1] with four replications. After 24 h, the larvae were observedand the percent parasitization was calculated. The same parasitoids were used for thesecond, third, fourth, and fifth instars larvae of H. armigera. &#x0D; To examine the parasitic potential of C. blackburni, another experiment was conducted with various ratios of its adults and eggs of E. vittella and H. armigera by adopting the procedure of Swamiappan and Balasubramanian [2]. The parasitoid and host eggs were maintained at a ratio of 1:100, 2:100, 3:100, 4:100, and 5:100 with four replications. The observation of percent parasitization was recorded after the egg incubation period.&#x0D; Results: The parasitic potential studies showed that the parasitoid host ratio of 5:10 (100%) was the best for E. vittella (II, III and IV instar larvae) with the highest parasitization followed by 4:10 (96.83 %), 3:10 (85.08 %), 2:10 (61.71 %) and least parasitization was observed in 1:10 parasitoid host ratio (52.71 %). Similarly, for H. armigera (II, III, IV and V instar larvae) parasitoid host ratio of 5:10 was recorded the highest parasitization (96.75 %), followed by 4:10 (93.69 %), 3:10 (84.11 %), 2:10 (64.75 %) and least parasitization was observed in 1:10 parasitoid host ratio (45.07 %)&#x0D; The parasitic potential of C. blackburni revealed that the 5:100 parasitoid host ratio resulted in the maximum parasitization of 64.75% against E. vittella, followed by 4:100 (60.50%), 3:100 (52.55%), 2:100 (38.27%), and 1:100 (25.60%). Similarly, for H. armigera, parasitization was highest at a parasitoid host ratio of 5:100, followed by 4:100 (64.50%), 3:100 (58.25%), 2:100 (43.45%), and 1:100 (28.50%).&#x0D; Conclusion: The parasitoids: host ratio of 5:10 for B. brevicornis and 5:100 for C. blackburni is optimal for managing the bhendi fruit borer complex at the IV instar level.

A SIMPLE MASS REARING METHOD FOR BRINJAL SHOOT AND FRUIT BORER &lt;i&gt;LEUCINODES ORBONALIS&lt;/i&gt; GUENEE

A simple, effective and economically cheaper method for mass rearing of the brinjal shoot and fruit borer, Leucinodes orbonalis Guenee was developed using both modified artificial diet fortified with brinjal powder and natural diet - potato. A comparison of the various biological parameters such as egg incubation period, larval period, larval weight (12-day old), pre-pupal period, pupal period, pupal weight (1-day old), adult longevity, fecundity, oviposition period and sex ratio of different life stages of the test-insect were studied for both the food sources in this investigation. The larval and pupal periods on natural (potato) diet were 14.58± 1.51 and 6.7± 1.22 days respectively, with a mean fecundity of 165.55± 36.26 per female and a mean life cycle of 26.91days. The larval and pupal period of shoot and fruit borer reared on modified diet were 15.97± 1.24 and 6.25± 1.23 days respectively with a mean fecundity of 149.45± 25.83 per female and a mean life cycle of 25.26 days. Provision of a suitable site for adult mating and oviposition was attained by designing a separate mating chamber along with a suitable egg laying substratum. Thus, an easy and economical rearing technique could successfully support the rearing to six generations of target-insect in laboratory.

"Biology of the invasive shell lerp psyllid, Spondyliaspis cf. plicatuloides (Froggatt) (Hemiptera: Aphalaridae)"

Spondyliaspis cf. plicatuloides (Froggatt) (Hemiptera: Aphalaridae) is native to Australia but was first detected outside its native range in 2014, in South Africa. It feeds on eucalypt species and thus has the potential to become a pest in commercial Eucalyptus plantations. Information on the basic biology of this insect, which is important for the development of surveillance and management strategies, is lacking. To investigate the life cycle and general biology of S. plicatuloides, the psyllid was reared under controlled glasshouse conditions on potted red-flowering gum, Corymbia ficifolia. The egg incubation period, number of nymphal instars and their developmental time, adult fecundity, adult longevity and duration of the life cycle were determined. The major diagnostic features used to differentiate the five nymphal instars were the number of antennal segments, wing pad development and body length. Females reached reproductive maturity 2.3 ± 0.47 (mean ± SD) days after eclosion and laid 16.2 ± 3.9 (mean ± SD) eggs on average. Reproduction was sexual. The first nymphal instar took 10.7 ± 1.2 (mean ± SD) days to hatch from the egg. The nymphal instars completed their development in 22.6 ± 1.4 (mean ± SD) days under the brown scalloped shelters they secrete. The insect's total life cycle lasted 37.37 ± 1.17 (mean ± SD) days from egg to adult death. Males and females lifespan is also reported. The study provides the first information on the basic biology of S. cf. plicatuloides that will be useful for future studies on surveillance and management strategies.

Life Cycle and Feeding Efficacy of Micromus Igortus (Bank) Brown Lacewing Against Myzus Persicae (Sulzer)

Myzus persicae(Sulzer) (Hemiptera : aphididae) is most polyphagous and economically important pest.Managment of M.persicae by using insecticide and pesticide is difficult as they resides under leaves and curls. Natural enemies play important role in controlling pest population. M.persicae have wide range of predators such as coccinellid beetle, lacewings, syrphid flies, spiders and aphid midges. Some hymenopteran parasitoids significantly lower population such aof Aphidius matricariae (Haliday Braconidae) and Aphelinus asychis Walker (Aphelinidae) and Diatellaria rapae. Micromus igortus Bank (Brown lacewing) has average predator potential against M. persicae than other aphid species. Micromus igortus mostly feed on Aphis craccivora and followed by Aphis gossypi. Biology and feeding efficacy of brown lacewing were studied in the fields from Kolhapur district, Maharashtra under laboratory condition in Shivaji University, Kolhapur. All stages of Brown lacewing and adults also have significant predatory potential against M.persicae. Feeding potential increases as the instars progressed their development. Rate of consumption on stage of 1st ,2nd, and 3rd instar of lacewing were average 11.15 days (Range Minimum 6.8 – Range maximum 15.5 days), 39.135 days (Range min. 23.5 – max. 31.27 days), 52.48 days (Range min. 46.91- max. 58.04 days ) respectively per day. Third instar is proved to be most prodigious feeder as they feed on large number of aphids. Lifecycle period for egg incubation, larval development, prepupal, pupal and adult period,total lifespan were 4.36 days(Range min. 4- max.5 days), 6.2 days (5-7 days), 1.3 days (1-2 days), 6.1 days (5-7days),9.6 days(8-12 days),29.32 days (28-32 days) respectively. The above studies will help to know the lifecycle of Lacewing in field conditions and proves the predatory potential of brown lacewing.

Insecticidal Activity of Medicinal Plant, Schinus molle (Anacardiaceae) on Tribolium confusum (Coleoptera: Tenebrionidae)

The insecticidal and repellent properties of essential oil and powder forms of Schinus molle were evaluated on Tribolium confusum in laboratory conditions. As a result of the studies, it was revealed that the average lifespan of T. confusum was 30±2 days. Egg incubation period was 10 days while the fecundity was 78 eggs/female. Sex ratio was observed as 1.06 female/male. In vitro insecticidal tests showed that the essential oil of S. molle was more effective with a mortality rate of 100% in 24 hours. The adults (males and females) of T. confusum survived for less than 24 hours in powder of S. molle. The repellence test of the essential oil provided variable levels of protection ranging from 78% to 100%.

Potensi Minyak Buah Merah (Pandanus conoideus) Sebagai Suplemen Pakan Induk Kepiting Bakau untuk Meningkatkan Performa Telur dan Larva

The effort to provide the seeds of mud crabs should be increased. The problem faced is the survival rate of larvae to reach megalopa stages are still low. Research has shown that nutrients contain antioxidants in the brood feed can keep the quality of reproduction. The red fruit Pandanus conoideus endemic plant of Papua Province in Indonesia, contain antioxidant nutrients are assumed be served to prevent oxidation of the egg so that it can improve the quality of the ovaries and subsequent larval survival. Experiment with feed delivered to mud crab Scylla serrata weighing 400-500g / ind. The experiments conducted using a completely randomized design with three composisitin of feed and three individual as replication. The feed A (control): flesh fish of Decapterus sp. 100g; Feed B: fish of Decapterus sp. 23g, squid 40g, and 37g RFO; Feed C: fish of Decapterus sp 41g, squid 24g, and 35g RFO. The measured parameters are achievement of a mature ovary, the egg incubation period, the diameter of the eggs, and protein and fat content of larvae. Data were analyzed by ANOVA. The results showed that brood crabs fed with supplementation RFO has the quality of the eggs and larvae are higher than brood crabs that fed without RFO.

Effect of temperature on incubation period and hatching of neon tetra Paracheirodon innesi eggs

Effect of temperature on incubation period and hatching of neon tetra Paracheirodon innesi eggs

Biology of Pink Bollworm Pectinophora gossypiella (Saunders) (Gelechiidae: Lepidoptera) under Laboratory Conditions

The present study on biology of pink bollworm on two modified artificial diets separately was carried out in the Toxicology laboratory, Department of Agriculture Entomology, Post Graduate Institute, Dr PDKV, Akola during October to February 2018–19 and 2019–20 with controlled conditions such as 25±2oC temperature 65±5% RH and photoperiod of 14:10 h light: dark. Two modified artificial diets were prepared separately with some modifications in the ingredients, pink bollworm larvae are reared on two above said modified artificial diets and observations were recorded on different biological parameters like egg incubation period (days), larval period (days), pupal period (days), adult emergence (%), adult male and female longevity(days), preoviposition period (days), oviposition (days), fecundity(no of eggs per female), total life cycle(days) and on morphometry of different stages pink bollworm like egg, first, second, third and fourth instar larval stages, male and female pupa and male and female adult moth. Our results indicated that pink bollworm has four larval instars with mean larval duration of 18.60±0.54 days in modified artificial diet 1 and 17.72±0.36 days in modified artificial diet 2 population respectively. Total life cycle from egg to adult was 46.74±0.31 and 54.71±0.62 days in modified artificial diet 1 and modified artificial diet 2 population respectively. Total life cycle of pink bollworm was completed somewhat earlier in in modified artificial diet 1 in comparison to modified artificial diet 2. Our results showed that there was only a little difference in the biology of pink bollworm on both modified artificial diets, and hence both modified artificial diets can be used for laboratory rearing purposes.

Periviscerokinin (Cap2b; CAPA) receptor silencing in females of Rhipicephalus microplus reduces survival, weight and reproductive output

BackgroundThe cattle fever tick, Rhipicephalus (Boophilus) microplus, is a vector of pathogens causative of babesiosis and anaplasmosis, both highly lethal bovine diseases that affect cattle worldwide. In Ecdysozoa, neuropeptides and their G-protein-coupled receptors play a critical integrative role in the regulation of all physiological processes. However, the physiological activity of many neuropeptides is still unknown in ticks. Periviscerokinins (CAP2b/PVKs) are neuropeptides associated with myotropic and diuretic activities in insects. These peptides have been identified only in a few tick species, such as Ixodes ricinus, Ixodes scapularis and R. microplus, and their cognate receptor only characterized for the last two.MethodsExpression of the periviscerokinin receptor (Rhimi-CAP2bR) was investigated throughout the developmental stages of R. microplus and silenced by RNA interference (RNAi) in the females. In a first experiment, three double-stranded (ds) RNAs, named ds680-805, ds956-1109 and ds1102-1200, respectively, were tested in vivo. All three caused phenotypic effects, but only the last one was chosen for subsequent experiments. Resulting RNAi phenotypic variables were compared to those of negative controls, both non-injected and dsRNA beta-lactamase-injected ticks, and to positive controls injected with beta-actin dsRNA. Rhimi-CAP2bR silencing was verified by quantitative reverse-transcriptase PCR in whole females and dissected tissues.ResultsRhimi-CAP2bR transcript expression was detected throughout all developmental stages. Rhimi-CAP2bR silencing was associated with increased female mortality, decreased weight of surviving females and of egg masses, a delayed egg incubation period and decreased egg hatching (P < 0.05).ConclusionsCAP2b/PVKs appear to be associated with the regulation of female feeding, reproduction and survival. Since the Rhimi-CAP2bR loss of function was detrimental to females, the discovery of antagonistic molecules of the CAP2b/PVK signaling system should cause similar effects. Our results point to this signaling system as a promising target for tick control.Graphical

BIOLOGY AND MORPHOMETRICS OF THE FALL ARMYWORM, Spodoptera frugiperda J. E. SMITH (LEPIDOPTERA: NOCTUIDAE) IN IBADAN, SOUTHWEST NIGERIA

Studies on the development and morphological description of the fall armyworm, Spodoptera frugiperda are important for its sustainable management on the continent. Such studies are, however scanty in Africa and non-existent in Nigeria. Consequently, we studied fall armyworm development on maize leaves from egg to moth. Data was collected on egg hatchability, development duration, and morphometrics of life stages. Total development duration for egg, larva, and pupa was 2–3, 11–12, and 7–10 days, respectively. Egg incubation period, diameter, and percentage hatchability were 2.10±0.06 days, 0.24±0.01 mm, and 81.50±2.28 %, respectively. Larva comprised six-instars; with the first and last respectively measuring 1.64±0.03 mm and 26.45±0.44 mm body-length, 0.18±0.01 and 3.45±0.07 mm body-width, 0.12±0.01 mm, and 2.45±0.02 mm head-capsule-width. Pupa body-length and body-width were 14.38±0.14 mm and 4.21±0.04 mm, respectively. Female moths were larger and emerged a day ahead of males. Body length, body width, and wingspan of male and female moths were 14.93±0.25 mm and 14.66±0.19 mm; 2.71±0.08 mm and 3.14±0.05 mm; and 13.65±0.24 mm and 14.17±0.14 mm, respectively. Development duration of S. frugiperda larvae in Nigeria is shorter than that reported in the Americas but within the range reported in other parts of Africa. Findings in the study also confirm the ability of S. frugiperda moths to survive without food for up to a week making them a possible contaminant of maize grains and other agricultural commodities during transcontinental trades. Information provided in this study will aid the detection, identification, and management of the pest on farmers’ field and on traded commodities.