Early life history of mebaru,sebastes inermis (scorpaenidae), in sendai bay, japan

The early life history of the viviparous scorpaenid,Sebastes inermis, in Sendai Bay, Japan, was studied and early development described. Newborn preflexion larvae ofS. inermis were about 5.2 mm BL. Notochord flexion occurred at 5.4–8.0 mm BL and transformation at 14–20 mm BL. Preflexion and flexion larvae ofS. inermis were distinguished from similar larvae by the pigmentation pattern along the dorsal and ventral midlines of the tail. Pigmentation inS. inermis was light throughout the larval and early juvenile periods. Planktonic larvae were particularly abundant in coastal waters of Sendai Bay but not offshore. Vertical and horizontal larval sampling indicated that early larvae occupied near surface waters and horizontal larval sampling indicated that early larvae shift to a benthic habitat occurred at about 12 mm BL, at the end of the postflexion larval period.Sebastes inermis do not have a distinct pelagic juvenile stage, unlike many North Pacific species ofSebastes.     

Reproduction and larval development of the gastropod molluskTegula rustica in Peter the Great Bay, Sea of Japan

The reproduction and larval development of the prosobranch gastropod molluskTegula rustica were studied under laboratory conditions. In Vostok Bay (Peter the Great Bay), the reproduction of theTegula takes place in August, when the water temperature is 19–20°C. Under laboratory conditions, the spawning of females was stimulated by adding a sperm emulsion to a vessel containing adult females. We observed asynchronous and intermittent release of gametes. The egg cell is 190 μm in diameter. Fertilization is external, and the course of development includes a lecithotrophic pelagic larva. Complete development, from fertilization to metamorphosis, takes 7 days in a laboratory culture. The larvae settle when the shell size across the first whorl is 220–230 μm and the total shell whorl is about 90°. The shape of the veliger shell is elongated mitriform and the velum is rounded, made up of a single lobe. The sculpture of the protoconch is irregularly ribbed.     

Laboratory rearing of the squirrel fleaCeratophyllus sciurorum sciurorum with notes on its biology

A rearing method for the fleaCeratophyllus (Monopsyllus) sciurorum sciurorum, a pest on farmed mink in Europe, has been developed. The behaviour of egg-laying and the development period are described at 23 °C and 80% r.h. The eggs ofC. sciurorum sciurorum hatched after 4–7 days and cocoons were formed 10–12 days later. The development period from egg to newly emerged adult was 23–32 days. Females emerged, in general, earlier than males.     

Development of eggs, larvae and juveniles of laboratory-reared blue whiting,Sillago parvisquamis (Percoidei: Sillaginidae)

The embryonic, larval and juvenile development of blue whiting,Sillago parvisquamis Gill, are described from a series of laboratory-reared specimens. Mean egg diameter and mean total length (TL) of newly-hatched larvae were 0.71 mm and 1.58 mm, respectively. The eggs were non-adhesive, buoyant and spherical with an oil globule (mean diameter 0.18 mm). Hatching occurred about 20 hours after fertilization at a temperature of 24.0–25.0°C, newly-hatched larvae having 38–40 myomeres. The yolk and oil globule were completely absorbed 3 days after hatching at 2.8–3.2 (mean 3.0) mm TL. Notochord flexion was completed by 7.2–8.2 (7.7) mm TL, and pectoral and caudal fin rays fully developed by approximately 10 mm and 8.5 mm TL, respectively. Completion of fin development occurred in the following sequence: caudal, pectoral, anal and second dorsal, first dorsal and pelvic, the last-mentioned by approximately 11 mm TL. The larvae ofS. parvisquamis andS. japonica, which closely resemble each other in general morphology and pigmentation, could be distinguished as follows. Newly-hatchedS. parvisquamis larvae had more myomeres thanS. japonica (38–40 vs. 32–34) and more melanophores on the dorsal surface of the body (19–28 vs. about 40).Sillago japonica had a vertical band of melanophores on the caudal peduncle, which was lacking in postflexionS. parvisquamis larvae. In addition, juveniles ofS. parvisquamis (larger than 23 mm TL) had melanophores on the body extending anteriorly to below the lateral line to form a midlateral band, whereas no obvious band occurred on similarly-sizedS. japonica juveniles.     

Rearing of two predators,Thanasimus dubius andTemnochila virescens, for the biological control ofIps grandicollis in Australia

Rearing methods for two coleopterous predators,Thanasimus dubius andTemnochila virescens, imported into Australia for the biological control ofIps grandicollis, were developed. Bionomic data obtained from laboratory rearings between 1982–1987 showed thatT. dubius eggs took about 7 days to hatch and that duration of the larval stage was about 42 days. Observations showed thatT. dubius had a prolonged prepupal stage (x=56.4 days, range 14–274 days), which was probably non-diapausal in nature. Mean adult longevity was 50 days (range 1–358 days).Temnochila virescens eggs took almost 9 days to hatch, and a lengthy larval stage (x=155.4 days, range 73–333 days) was observed. Mean duration of the pupal stage was 14 days (range 7–28 days). A long preoviposition period (x=141 days, range 47–206 days) was observed, and adults were very long-lived (x=232.7 days, range 14–667 days). Capacity for increase (r_c) calculated from rearing data suggested that numbers ofT. dubius could be increased faster thanT. virescens. Mortality between 1982–1987 averaged about 70% for both species. However, mortality ofT. dubius in 1987 increased significantly, suggesting that inbreeding or other methodological factors could be responsible. A mass-rearing method usingIps-infested pine billets was developed as a cheaper alternative to laboratory rearing, and was shown to be effective in producing large numbers of insects for release.     

Studies ontrichogramma buesi as a biocontrol agent againstPieris rapae in Egypt

Trichogramma buesi was reared in the laboratory on eggs of the Mediterranean flour moth,Anagasta kuehniella. The incubation period of the parasite's egg was 27 h at 23 °C and 22 h at 27 °C. The larval stage lasted 3.6 and 3.2 days, the pre-pupa lasted 16 and 23 h, and the pupa lasted 5.4 and 4.6 days at 23° and 27°C, respectively. The total developmental time (from egg to adult) averaged 9.2, 9.4, and 9.1 days when the parasite was reared on eggs ofPieris rapae, Spodoptera littoralis, andA. kuehniella, respectively, at 27 °C. Sex ratio inT. buesi was 1 ♂: 1 ♀ in nature and 1 ♂: 1.3 ♀ in the laboratory. The daily and total numbers or progeny produced/female were 5.1 and 98.2 adults, respectively. The parasite female, fed on honey, lived 10.7 days at 27 °C and 12.1 days at 23 °C. Percentages of parasitism byT. buesi on eggs ofP. rapae collected from cabbage fields ranged between 0 and 31.5 % in 1985 and betwcen 0 and 36.4% in 1986 during July through December. The respective figures on eggs collected from turnip fields were 16–42.2% and 12.5–32.1% during November and December.      

Biology and population development ofAblattaria arenaria [Coleoptera: Silphidae], a snail predator

The biology ofAblattaria arenaria (Kraatz) was studied in the laboratory by using a helicid snail,Xeropicta derbentina (Kyrnicki) as prey. Population development ofA. arenaria in the field was studied in 1985 and 1986. The eggs ofA. arenaria were laid in the soil in lots of 5–45 at various intervals, and the total number of eggs per female varied from 144 to 193 during the oviposition period of 24–88 days.A. arenaria passed through the egg, 3 larval, prepupal, and pupal stages before reaching the adult stage. The mean duration of these stages was 9.8, 3.9, 2.5, 5.9, 3.8 and 5.7 days, respectively, with a total of 31.4 days. A. arenaria overwintered as an adult and became active and laid eggs during the spring. The start of spring activity seemed to be highly influenced by relative humidity. High humidity resulted in early emergence from overwintering sites. There was 1 generation in 1985, but 2 population peaks occurred in 1986. Immature stages of the 2nd generation became adult before the beginning of aestivation. Activity of the beetles was stopped by the beginning of hot weather in June, which synchronized well with the beginning of snail aestivation.      

RearingTrichogramma nubilale [Hymenoptera: Trichogrammatidae] on eggs of the tobacco hornworm,Manduca sexta [Lepidoptera: Sphingidae]

The fresh frozen egg of the tobacco hornworm (TBH)Manduca sexta (L.), is an efficient and superior host for mass production ofTrichogramma nubilale Ertle & Davis. Each host egg may produce 10.7±2.8 (n=7) large, robust, and activeT. nubilale. The proportion of ♀♀ stabilized at 80–90% with 69.9±26.6 (n=8) ovarian eggs per female. As many as 3 ♀♀ were observed ovipositing simultaneously into a single TBH egg. Superparasitism (>10 progeny) should be avoided because it may cause nutritional or space limitations on the development of effectiveT. nubilale.      

Life history characteristics of the clam<Emphasis Type="Italic"> Mya arenaria</Emphasis> in the White Sea

Dynamics of Mya arenaria beds in two bights of the Chupa Inlet (Kandalaksha Bay, White Sea) were studied on a long-term basis. Observations were carried out at 1– to 3-year intervals from 1979 up to 1999. The studied soft-shell clam beds were characterised by a substantial instability of age structure. Since 1988, only one year-class has dominated in the beds while other generations have been scarce and recruitment was not observed. This pattern of Mya bed dynamics was related neither to interannual environmental changes nor to differential reproduction success or predation effects in the benthic assemblages. Favourable conditions for spat formation in 1988 (low abundance of other M. arenaria generations), as well as for juvenile survival during the following winter, resulted in high abundance of juveniles in both investigated locations in 1989. The mortality rate (μ) in this 1988 generation varied throughout the period of investigation and was related to age. The mortality level decreased for the first 2–4 years of the life cycle, then stabilised for the next 3–4 years, and eventually increased in subsequent years. Overall μ values ranged from 0 to 1.68 year^–1. The oldest specimens observed were 17 years old and had a maximum shell length of 79 mm. Significant differences in average growth rates were observed between molluscs of different locations. Communicated by H.-D. Franke     

Larval mortality of pine sawflies [Hymenoptera: Diprionidae] in relation to pollution level: A field experiment

Larval mortality ofNeodiprion sertifer (Geoffroy),Diprion pini (L.) andGilpinia pallida (Klug) were studied in field experiments around a factory complex in southwestern Finland. Larval colonies were transferred on the shoots of Scots pines growing at different distances from the emission source. Larval mortality was highest near the factories. InN. sertifer, larval mortality caused by the nuclear polyhedrosis virus was higher and cocoon mortality caused by parasitoids was lower near the pollutant source. The most abundant parasitoid species wereSynomelix scutulata (Hartig) andLamachus eques (Hartig). 16–67% of theN. sertifer, 0–5% of theD. pini and the 73–100% ofG. pallida cocoons contained parasitoids oviposited during the larval period of the sawflies.      

Continuous rearing of the maize stem borerBusseola fusca on an artificial diet

Busseola fusca (Fuller) (Lepidoptera: Noctuidae) is a major pest of maize and sorghum in many countries of tropical Africa. Hitherto, research on this important pest has been hampered by the occurrence of a six-month long diapause in the last larval stage and the lack of an artificial diet for rearing the insect in the laboratory. Incorporating 4 to 8-week-old sorghum powder in a nutritionally adequate diet and rearing larvae individually in vials at ambient laboratory conditions (25–30°C, 50–80% r.h., and L12: D12) have made it possible to rear 15 successive non-diapausing generations ofB. fusca capable of producing between 35 to 40 healthy pupae/litre of diet and upto 70% pupation without loss of vigour or reproductive capacity. Five to six generations were completed per year and the overall mean developmental period (egg-egg) was 68 days (egg 6, larval 45, pre-pupal 1, pupal 14 and pre-oviposition 2 days). Larval period lasted 70 days in the first generation compared to 32.3 days in the fifteenth generation. Average fecundity increased from 158.0 to 394.6 eggs per female with a concomitant increase of egg hatch from 44.8 to 79.6% in the first and fifteenth generation, respectively.     

Fecundity and Longevity of Green Vegetable Bug,Nezara viridula, Following Parasitism byTrichopoda giacomellii

The effects of parasitism by the ArgentinianTrichopoda giacomellii(Blanchard) on reproduction and longevity of its host,Nezara viridula(L.) are reported. Parasitoid larvae suppress egg maturation, reducing by 70% the fecundity of mature female hosts during the period of larval development. Egg viability was not affected, but mating frequency was reduced by approximately 50%. When parasitized as newly eclosed adults, 84% of females fail to reproduce. In male hosts, fertility and mating frequency were not affected during the period of larval parasitoid development. In male and reproductively immature female hosts, death was coincident with, or occurred shortly after parasitoid emergence (2–4 days); in mature females, death occurred on average 2 weeks after larval parasitoid emergence. Host mortality occurred as a consequence of tissue damage incurred as the parasitoid larvae emerged from the host. Some individuals survived parasitism though no further reproductive activity (mating or oviposition) occurred. The effectiveness ofT. giacomelliias a biological control agent is discussed in relation to its impact on reproduction and survival of its host and contrasted with the action of otherTrichopodaspecies.     

Sexual reproduction of the brooding sponge <Emphasis Type="Italic">Rhopaloeides odorabile</Emphasis>

Sexual reproduction of Rhopaloeides odorabile, a common Great Barrier Reef sponge, was quantified using histological sections from samples collected over two reproductive seasons. Rhopaloeides odorabile is viviparous and gonochoristic with a male biased sex ratio (2.5:1). Commencement and cessation of gametogenesis coincides with rising and falling sea surface temperatures (≈24–29°C). Spermatogenesis occurs from October until January. Females initiate oogenesis in September with the asynchronous development of oocytes, embryos and larvae occurring within the brood chambers. A larval release period of 5–6 weeks occurs during January and February. The minimum size of reproductive individuals was 176 cm³ for females and 192 cm³ for males. The total reproductive output for both sexes shows a positive correlation with size. A relative reproductive output index quantified the maximum reproductive investment at approximately 1 and 3% of the total choanoderm for females and males, respectively, which represents a lower range of reproduction in comparison to other viviparous sponges. Low reproductive output in R. odorabile may be offset by an extended spawning period, alleviating the risk of releasing larvae in potentially adverse conditions via one synchronised spawning event and increasing overall larval survival.     

Larval development of the rhizocephalanSacculina polygenea (Crustacea: Cirripedia)

Larval development of the rhizocephalanSacculina polygenea (Crustacea: Cirripedia: Rhizocephala) parasitizing the coastal crabHemigrapsus sanguineus was studied in Vostok Bay, the Sea of Japan. At 22–23°C, the entire cycle of larval development takes 2.5 days and includes five naupliar stages and one cypris stage. Like other rhizocephalans, the larvae ofS. polygenea are lecithotrophic and only grow slightly in size in the course of development, and like all sacculinids, they have no flotation collar. The naupliar stages IV and V have a tubercle between the furcal rami; this tubercle is absent in the larvae of the genusPeltogasterella, but it has been described inS. carcini. The first seta of the antennule only disappears completely at the fourth stage, although it is markedly reduced at the third stage. No morphological differences, except differences in size, are found between male and female nauplii.     

Energy flow and subsidies associated with the complex life cycle of ambystomatid salamanders in ponds and adjacent forest in southern Illinois

Breeding adults and metamorphosing larval amphibians transfer energy between freshwater and terrestrial ecosystems during seasonal migrations and emergences, although rarely has this been quantified. We intensively sampled ambystomatid salamander assemblages (Ambystoma opacum,A. maculatum, and A. tigrinum) in five forested ponds in southern Illinois to quantify energy flow associated with egg deposition, larval production, and emergence of metamorphosed larvae. Oviposition by female salamanders added 7.0–761.4 g ash-free dry mass (AFDM) year⁻¹ to ponds (up to 5.5 g AFDM m⁻² year⁻¹). Larval production ranged from 0.4 to 7.4 g AFDM m⁻² year⁻¹ among populations in three ponds that did not dry during larval development, with as much as 7.9 g AFDM m⁻² year⁻¹ produced by an entire assemblage. Mean larval biomass during cohort production intervals in these three ponds ranged from 0.1 to 2.3 g AFDM m⁻² and annual P/B (production/biomass) ranged from 4 to 21 for individual taxa. Emergent biomass averaged 10% (range=2–35%) of larval production; larval mortality within ponds accounted for the difference. Hydroperiod and intraguild predation limited larval production in some ponds, but emerging metamorphs exported an average of 70.0±33.9 g AFDM year⁻¹ (range=21.0–135.2 g AFDM year⁻¹) from ponds to surrounding forest. For the three ponds where larvae survived to metamorphosis, salamander assemblages provided an average net flux of 349.5±140.8 g AFDM year⁻¹ into pond habitats. Among all ponds, net flux into ponds was highest for the largest pond and decreased for smaller ponds with higher perimeter to surface area ratios (r ² =0.94, P<0.05, n=5). These results are important in understanding the multiple functional roles of salamanders and the impact of amphibian population declines on ecosystems. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.     

Developmental morphology of the Indian cyprinid fish Barilius canarensis

Embryonic and larval development of an Indian cyprinid fish, Barilius canarensis, is described from laboratory-reared specimens. The eggs, measuring 2.1–2.4 mm in diameter, were demersal, almost spherical in shape, transparent and unpigmented, with a pale yellow yolk without oil globules. Hatching occurred 39–45 h after fertilization at 26.8°–27.4°C. The newly hatched larvae, measuring 4.8–5.1 mm in body length (BL) with 22 + 17 = 39 myomeres, were characterized by melanophores already deposited on the eyes. The eggs of B. canarensis resembled those of the related danionin species Candidia barbatus, Opsariichthys uncirostris uncirostris, Zacco platypus, Z. sieboldii, and Z. temminckii. Although the larvae of B. canarensis were also similar to those of the foregoing species in general morphology, they differed in having a straight notochord tip and pigmentation on the eyes at hatching and the almost entire absence of melanophores on the ventral body surface from the yolk sac to postflexion larval stages. Conversely, melanophores occurred on the anterior abdominal and pericardial cavities from the preflexion to postflexion larval stages.     

The hydrochemical regime of the habitat of the red algaAhnfeltia tobuchiensis population in the Bay of Izmena (Kunashir Island)

In 1989–1990 and 1997, in the Bay of Izmena (Kunashir Island), the spatial distribution ofAhnfeltia tobuchiensis (Kanno et Matsubara) Mak, an unattached agar-containing red alga, was studied, and the availability of biogenic elements for the process ofA. tobuchiensis primary production was assessed. The concentrations of dissolved O₂, ammonium [NH ₄ ⁺ ], and orthophosphate [PO ₄ ³⁻ ], were highest in the central and northeastern areas of the bay, where the bulk of the population is situated. During the day, the mean oxygen concentration above the alga bed increased from 8.2±0.09 to 8.7±0.08 mg/l, showing a high rate of photosynthesis in the population. As a result of diurnal ammonium and orthophosphate assimilation by the alga, their concentration in bottom waters dropped from 5.1 to 3.5 and from 0.45 to 0.35 μM/l, respectively. Proceeding from the mean values of the nitrogen to phosphorus atomic ratio in the bay waters (11.5±3.3 in the morning and 10.6±3.3 in the evening) and in algal thalluses (33 in the case ofA. tobuchiensis), we conclude that the concentration of major biogenic elements is sufficient for the processes of primary production in the Bay of Izmena.     

Symphurus hondoensis Hubbs, 1915, a valid species of western Pacific tonguefish (Pleuronectiformes: Cynoglossidae)

Symphurus hondoensis Hubbs, 1915, originally described only from the holotype taken in 390–542 m in Suruga Bay Japan, has long been considered a junior synonym ofS. strictus Gilbert, 1905, known from waters off Hawaii, Japan, the Philippine Islands, and South Africa. Based on new information from the holotype and a specimen recently captured from deep waters (789–815 m) off Amami-Oshima Island, southern Japan,S. hondoensis is now established as a valid species.Symphurus hondoensis is unique among congeners in having the combination of a 1–2–3 pattern of interdigitation of proximal dorsal pterygiophores and neural spines, 10 abdominal vertebrae, 14 caudalfin rays, 111–113 dorsal-fin rays, 95 anal-fin rays, 59 total vertebrae, 105–106 scales in longitudinal series, blind side nearly as darkly pigmented as the ocular surface, and a black peritoneum. Recognition ofS. hondoensis increases the number of described species ofSymphurus in waters off Japan to three (S. orientalis Bleeker,S. strictus, andS. hondoensis), with at least one more underscribed species occurring in deepwater hydrothermal vent areas off southern Japan.     

Biological studies ofAmblyseius olivi,a new predator of eriophyid mites infesting olive trees in Egypt [Acari: Phytoseiidae]

The development was faster and reproduction was higher whenAmblyseius olivi Nasr & Abou-Awad fed on the eriophyid miteEriophyes olivi Zaher & Abou-Awad. The duration increased and reproduction decreased on the tetranychid miteTetranychus (T.) uriticae Koch. The predator female consumed daily 120 and 8 individuals ofE. olivi andT. (T.) uriticae respectively. The daily reproduction was as low as 0.6–0.3 eggs/♂/day when females were maintained on royal jelly, molasses, honey or their combinations.

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Résumé Le développement était plus rapide et la reproduction était plus élevée quandAmblyseius olivi Nasr & Abou-Awad se nourrissait de l'Eriophyide:Eriophyes olivi Zaher & Abou-Awad. La durée augmentait et la reproduction décroissait avecTetranychus urticae Koch. Le prédateur femelle consommait quotidiennement 120 et 8 individus deE. olivi et deT. (T) urticae. respectivement. La reproduction quotidienne était faible 0,6–0,3 œuf/♂/jour quand les femelles étaient maintenues sur gelée royale, molasses, miel ou leurs combinaisons.

     

Host–parasitoid interaction as affected by interkingdom competition

Although still underrepresented in ecological research, competitive interactions between distantly related organisms (so-called “interkingdom competition”) are expected to be widespread in various ecosystems, with yet unknown consequences for, e.g. trophic interactions. In the model host–parasitoid system Drosophila melanogaster–Asobara tabida, toxic filamentous fungi have been shown to be serious competitors that critically affect the density-dependent survival of host Drosophila larvae. This study investigates the extent to which the competing mould Aspergillus niger affects key properties of the well-studied Drosophila–parasitoid system and how the host–parasitoid interaction influences the microbial competitor. In contrast to slightly positive density-dependent host mortality under mould-free conditions, competing A. niger mediated a strong Allee effect for parasitised larvae, i.e. mortality decreased with increasing larval density. It was found that the common toxic fungal metabolite kojic acid is not responsible for higher death rates in parasitised larvae. Single parasitised Drosophila larvae were less harmful to fungal reproduction than unparasitised larvae, but this effect vanished with an increase in larval density. As predicted from the negative effect of fungi on host survival and thus on parasitoid fitness at low larval densities, A. tabida females spent less time foraging in fungus-infested patches. Interestingly, even though high host larval densities increased host survival, parasitoids still reduced their search efforts in fungus-infested patches, indicating a benefit for host larvae from feeding in the presence of noxious mould. Thus, this experimental study provides evidence of the potentially important role of interkingdom competition in determining trophic interactions in saprophagous animal communities and the dynamics of both host–parasitoid and microbial populations.