Potential of Blaptostethus pallescens Poppius (Hemiptera: Anthocoridae) on Tetranychus truncatus Ehara (Prostigmata: Tetranychidae)

Efficiency, functional and numerical responses of anthocorid bug Blaptostethus pallescens Poppius on the spider mite, Tetranychus truncatus Ehara were examined under laboratory conditions. Nymphs of B. pallescens exhibited a Hollings type II functional response when females of spider mite were offered at densities of 10, 20, 30, 40, 50, 60 and 70 mites/bug. Individual fifth instar bugs consumed up to 45.3 adult females of T. truncatus in 24 h at prey mite densities of 60 mites/ bug. Studies on numerical response revealed that the nymphs of the anthocorid bug failed to complete development when the food was restricted to mite alone. Numerical response studies on adult bugs, when offered T. truncatus at densities of 10, 20, 30, 40 and 50 females showed no significant differences in the average fecundity of the female bug. Results indicate that the anthocorid predator, B. pallescens has a very high predatory potential though with a weak numerical response.

TEKNIS PRODUKSI PEMBENIHAN DAN PENDEDERAN IKAN LEMON ALGAE EATER Gyrinocheilus aymoneiri DI ADE’S FISH FARM, KABUPATEN BOGOR, JAWA BARAT

ABSTRACTLemon fish Algae Eater is one of the aquarium fish which is well-known as Algae Eater. The Lemon Algae Eater is placed in a pond measuring 2 m x 3 m x 0.8 m, with a water height of 50 cm. For optimum health, feed the Algae Eater with Feng Li pellets by having a restricted feeding method or this can also be limited to 5% from the brood fish weight. The semi-natural hatchery of Lemon fish Algae Eater is needed. An aquarium (100cm x 60 cm x 50 cm) with a water height of 30 cm is needed for the hatchery of Lemon fish Algae Eater eggs. The average fecundity of Lemon fish Algae Eater eggs produced in 1 spawning can reache up to 84 742 eggs with the average of Fertilization Rate is 79%, the Hatching Rate is 83%, and the Survival Rate is 74%. The Lemon Algae Eater eggs will hatch in 10-12 hours. Fish nursery of lemon fish algae eater is used pond measures 3 m x 2 m x 1.5 m. The freshly hatched larvae are harvested at the age of 30 days and 45 days with a size of 1.2-1.5 cm/fish and 2.5-3 cm/fish. ABSTRAKLemon algae eater merupakan salah satu ikan aquarium yang dikenal sebagai pemakan alga. Pemeliharaan ikan lemon algae eater dilakukan pada bak beton yang berukuran 2 m x 3 m x 0.8 m, dengan tinggi air 50 cm. Pakan yang diberikan berupa pelet feng li dengan metode pemberian pakan restricted atau metode dibatasi dengan 5% dari bobot induk. Pemijahaan induk ikan lemon algae eater dilakukan secara semi alami. Wadah penetasan telur ikan lemon algae eater menggunakan akuarium ukuran 100 cm x 60 cm x 50 cm dengan tinggi air 30 cm. Rata-rata fekunditas telur ikan lemon algae eater yang dihasilkan dalam 1 kali pemijahan mencapai 84 742 butir telur dengan memiliki nilai rata-rata Fertilization Rate sebesar 79%, Hatching Rate sebesar 83%, dan Survival Rate sebesar 74%. Telor ikan lemon algae eater akan menetas dalam waktu 10-12 jam. Kegiatan pendederan ikan lemon algae eater menggunakan wadah bak beton yang berukuran 3 m x 2 m x 1.5 m. Benih yang dipanen berumur 30 hari dan 45 hari dengan ukuran 1.2 -1.5 cm/ekor dan 2.5 - 3 cm/ekor.

Mild Abiotic Stress Affects Development and Stimulates Hormesis of Hemp Aphid Phorodon cannabis

The hemp aphid Phorodon cannabis Passerini is a well- known (Asia, Europe) or newly emerging (North America) insect. It is a monophagous insect pest causing considerable damage in field and glasshouse cultivations. The aim of this work was to study the effects of meteorological (temperature) and agronomical (herbicide) factors on the biology of the hemp aphid. In one experiment, hemp plants were kept at constant temperatures ranging from 20 to 30 °C, and aphid survival and fecundity were measured. In a related experiment conducted at 20 °C, plants were treated with field-appropriate rates of a selective graminicide containing quizalofop-P-tefuryl (40 gL−1, 4.38%, HRAC group 1), commonly used to control weeds in hemp, and aphid enzyme activity was measured in addition to population parameters. We found that hemp aphids could live, feed and reproduce within the whole studied range of temperatures, demonstrating its great evolutionary plasticity. However, the optimal temperature for development was 25 °C, at which the insect lived and reproduced for 25 and 15 days, respectively, with an average fecundity of 7.5 nymphs per reproduction day. The herbicide treatment increased the activity of superoxide dismutase (SOD), catalase (CAT), β-glucosidase, S-glutathione transferase (GST), oxidoreductive peroxidase (POD), and polyphenol oxidase (PPO) in the aphids, but only on certain days after treatment, which indicates a mild stress in aphid tissues, related to a higher reproduction and changed feeding behavior; aphids moved from the actively growing tips compared to untreated plants. The results of these experiments are discussed in terms of the impact on the future management of this pest.

CONDITIONS FOR THE FORMATION OF THE ARTEMIA CRUSTACEAN POPULATION AND THEIR PRODUCTION INDICATORS IN DIFFERENT TYPES OF HYPERHALINE LAKES OF THE ALTAI TERRITORY

Long-term data (2002–2019) on the conditions of the formation of Artemia populations in different types of hyperhaline lakes of the Altai Territory are analyzed. The boundaries of individual fecundity and average fecundity were calculated, the influence of abiotic factors on the quality content of ovisak was shown. The peculiarities of their changes at different levels of water salinity during the growing season have been investigated. The average number of litters (clutches) for Altai populations was calculated, the influence of environmental factors on this indicator was analyzed.

Sakhalin sturgeon Acipenser mikadoi (Acipenseridae): results of study and proposed measures for conservation of the species

All available data on sakhalin sturgeon Acipenser mikadoi are summarized. Its historical and modern habitats are described and their significant reduction is noted. Now the species is abundant in the Russian part of its range only — in the Tumnin River, where it is represented in commercial catches by two clearly different groups: large-sized juveniles (FL 43–68 cm) and mature fish (FL 135–169 cm). Juveniles of sakhalin sturgeon migrate during their first years, as their osmoregulatory system forms, to the lower reaches of Tumnin, to the internal estuary, and then to the Datta Bay, the Tatar Strait and the Japan Sea. When returned to the Tumnin, the spawners of sakhalin sturgeon have the length 135–169 cm (n = 29) and weight 15–36 kg. Sex ratio among the caught mature fish is 13.0 : 4 or 3.2 : 1 for females : males, on average. Fecundity of the sturgeon females sampled for artificial reproduction varied from 44.8 to 150.0 thousand eggs, on average 87.3 ± 12.1 . 103 eggs. In total, 17 mature spawners of A.mikadoi were caught in the Tumnin River in 2006–2019 for artificial reproduction (♀ = 13, ♂ = 4), 13 individuals were injected, among them 4/5 of females and 2/3 of males gave high-quality sex products. Producers of this species were distinguished by high survival during manipulations of fish breeding (100 %). Their progeny had low survival, both embryos during incubation and juveniles during rearing; the survival rate for the stage from eggs laid for incubation to juveniles with weight 3.4–7.0 g was 1.85 %. The low survival was supposedly reasoned by combination of unfavorable environmental factors and fish-breeding manipulations. Totally 11,214 juveniles of sakhalin sturgeon with weight from 3.4 to 7.0 g were released into the natural habitat (Tumnin river) in 2007, 2008, 2015, 2017, and 2019. At Anyui sturgeon fish hatchery, the broodstock of sakhalin sturgeon with 274 individuals of 5 ages is created and operated successfully. The male sturgeons in the hatchery mature at the age of 8 years. Here, 11 males of the 2007–2008 year-classes participated in the spawning in 2015–2019. Re-maturation of males was not recorded yet. For the broodstock formation in other fish hatcheries, 200 juveniles of sakhalin sturgeon were transferred to them. To preserve the species, a set of measures is proposed to strengthen its protection and to enhance its artificial reproduction, including the fry releasing into the rivers of the mainland coast, Sakhalin Island, and Japan.

Reproductive Biological Performance of Otolithes ruber (Bloch and Schneider 1801) in San Miguel Bay, Philippines

The tigertooth croaker, Otolithes ruber (Bloch and Schneider 1801), was studied to determine its reproductive biology characteristics for 34 months from March 2015 to November 2017. A total of 7,977 individuals were sampled and the measured total lengths (TL) ranged from 8.1 cm to 32.1 cm (16.70 ± 2.53 cm ) and 10.0 cm to 33.5 cm (17.95 ± 2.95 cm) for male and female, respectively. The length-weight relationship can be summarized as W = 0.00521 L3.18 and W = 0.00837 L3.01 for female and male, respectively. The length at first maturity of this species was determined to be 13.95 cm, which is smaller compared to other studies. The overall sex ratio of this species was 1:0.8, with males dominating the female sex (P < 0.05, X2 = 64.3). In addition, synchronized development of male and female gonads was observed. It was also verified that mature individuals were present all throughout the study period indicating that this species spawn continuously and the presence of juveniles during the sampling period indicated continuous recruitment. Mean monthly GSIs indicate July to November as the main spawning season of this species. The in-site occurrence of mature and juvenile stocks in the bay further implicates that San Miguel Bay is a nursery ground for this species. The fecundity varied between 3,420 to 422,100 with an average fecundity of 86,142 eggs. Lastly, the spawning potential ratio is still above the limit reference point (SPR = 0.36), indicating that the stock can still replenish their biomass.

Aspects of the reproductive biology of Pseudotolithus typus (Bleeker, 1863) from qua Iboe River Estuary, Nigeria

The study was conducted to assess the reproductive biology and condition index of Pseudotolithus typus in Qua Iboe Estuary using standard methods. A total of 580 fish specimen were sampled over a period of 8 months (January – August, 2018). Condition index was generally low with the highest value of 1.03 recorded in the month of April. The overall mean condition index significantly deviated (p<0.05) from the expected value of 1.0. Male-female ratio of the species showed female dominance. Significant variation (p<0.05) were observed in condition and gonadosomatic indices with peak values in the months of March and July for females. Male fish showed no seasonality in gonadosomatic index. The average fecundity ranged from 2140 eggs to 8560 eggs with mean value of 4891±641 eggs. Positive correlation was observed between fecundity and total length, body weight, standard length and gonad weight of the fish. Thus, it could be concluded that P. typus is a dual seasonal spawner having spawning periods early in the year (March) and in the peak of wet season (July). Keywords: Pseudotolithus typus, condition index, gonadosomatic index, fecundity, estuary.

Life table of Chrysoperla externa (Neuroptera: Chrysopidae) reared on Melanaphis sacchari (Hemiptera: Aphididae)

Chrysoperla externa is a widely distributed and highly adaptable predatory insect. In order to evaluate its capacity as a natural enemy of the sugarcane aphid, Melanaphis sacchari, its life table when reared on M. sacchari was inferred. The biological cycle lasted an average of 29.5 ± 6.2 d from egg to adult. The embryonic and larval period duration was 5.1 ± 0.3 and 13.8 ± 4.5 d, respectively. The pupa stage was completed in 10.6 ± 1.4 d, whereas adults lived 63.5 ± 26.7 d after eclosion. The mortality rate showed the highest values in the egg stage (qx = 0.17). The greatest survival rate appeared in the third instar (93.7 %). The period prior to reproduction was 6.5 ± 3.1 d. The average fecundity was 228.3 ± 139.1 eggs. The life table parameters were Ro = 113.2, T = 28.9, rm = 0.163 and λ = 1.17. According to the results, it is possible to infer that C. externa is capable of accomplishing its life cycle feeding only on M. sacchari.

Studi Biologi Hama Kutu Putih Pepaya Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococadea)

The goal of this research was to understand the biology of P. marginatus, a common pest for papaya plants. This research used 1 type of treatment which was repeated 10 times. The results of this research were intended to illustrate the average development time of each development phase of P. marginatus. These phases were: the egg phase (6 days), the female nymph phase (10 days), the male nymph phase (17 days), female adult stage (11 days), male adult stage (3 days). On average, the female life cycle was 27 days, and the male life cycle was 26 days. On average, the pre-fertile stage lasted 4 days, the fertile stage lasted 6 days and the post fertile stage lasted 1 day. On average the pre-egg-laying adult stage lasted 4 days, the egg-laying adult stage lasted 6 days and the post-egg-laying stage lasted 1 day. After the egg-laying stage, the average fecundity of P. marginatus was 370 eggs per female and from these, a total of 350 offspring were hatched per individual. The ratio of surviving Descendents to reproductive couples of P. marginatus white lice was 9:1.

Biology of anthocorid predator, Blaptostethus pallescens Poppius (Heteroptera: Anthocoridae)

Biology of anthocorid predator Blaptostethus pallescens Poppius was studied on eggs of alternate host Corcyra cephalonica (Stainton). Eggs of B. pallescens, thrust within the plant tissue, hatched after a mean incubation period of 5.78 days. Nymphs, when reared on UV sterilized eggs of C. cephalonica under ambient conditions, developed normally with five instars, each having a mean duration of 2.63, 1.92, 2.01, 2.50 and 5.10 days, respectively. Females laid eggs after a pre-oviposition period of 4.2 days. Average fecundity of bugs was 134.04 eggs. Mean longevity of females was found to be higher (52.03 days) than that of males (40.18 days).