The little dragon sculpinBlepsias cirrhosus,another case of internal gametic association and external fertilization

In the copulating cottid species,Blepsias cirrhosus, the point at which fertilization occurred was determined experimentally. Ovulated eggs were obtained directly from the ovary of impregnated females. Eggs maintained in ovarian fluid did not show any signs of development, whereas most of the eggs which had been placed in seawater had developed to the 4-cell stage after 24hrs. The eggs kept in ovarian fluid initiated segmentation when later transferred into seawater. Histological examination showed that a number of spermatozoa had entered the micropyle, but that penetration did not occur in eggs that were not immersed in seawater. In these eggs, the metaphase spindle of the second meiotic division was observed in the ooplasm, at the animal pole. These results indicate that, in impregnated females, the spermatozoa associate with the eggs in the ovarian cavity, but that fertilization occurs externally when the eggs are spawned.     

Utilization and ecological benefits of a sponge as a spawning bed by the little dragon sculpinBlepsias cirrhosus

It was established that the little dragon sculpinBlepsias cirrhosus uses the sponge speciesMycale adhaerens as a spawning bed. The eggs were completely concealed in the sponge tissues, and caused the sponge skeleton to be partly damaged. It is conceivable that the exclusive utilization ofM. adhaerens byB. cirrhosus is a consequence of the advantageous softness and thickness of the sponge which allows the fish to inject the eggs. The eggs deposited in the sponge seemed to take advantage of predator avoidance, a constant supply of oxygen, and little interference by bacteria.     

不同温度对三叶虫萤卵孵化和初孵幼虫发育的影响

本文研究了三叶虫萤Emeia pseudosauteri在不同恒温设置和室内变温条件下卵孵化率和初孵幼虫存活率,并通过直接最优法和直线回归法计算出了三叶虫萤卵的发育起点温度和有效积温。结果表明:12~30℃恒温条件下,卵的孵化率随着温度升高显著下降(P<0.05),且均低于室内变温条件(P<0.05)下的孵化率;初孵幼虫在恒温15℃下的存活率最高,为73.13%;低于12℃和高于30℃恒温中初孵幼虫均无法存活;在恒温条件12~30℃下,卵的发育历期随温度升高而缩短,其中恒温12℃下最长,发育历期为42.96 d(n=3),恒温30℃下最短,发育历期仅12.75 d(n=3)。通过直接最优法计算出三叶虫萤卵的发育起点温度为3.52℃,有效积温分别为382.20 d·℃。上述结果为三叶虫萤的人工繁育提供了参考。     

Cuticular sensilla on newly hatched larvae of Gasterophilus intestinalis and Oestrus ovis

Abstract. Cuticular sensilla on newly hatched larvae of Gasterophilus intestinalis De Geer (Diptera: Gasterophilidae) and Oestrus ovis (L.) were studied by scanning electron microscopy. Two types of trichoid sensilla, two types of coeloconic sensilla and a pit sensillum were present on the thoracic and abdominal segments of G. intestinalis larvae. Sensilla on larvae of O. ovis were similar although only one type of trichoid sensillum was present. Total number of sensilla were higher for O. ovis than for G. intestinalis (248 v . 214). Variation in numbers of sensilla is consistent with the concept that increasing numbers of sensilla are associated with increasingly complex searching behaviour required to locate suitable habitats for development.     

日本新糠虾胚胎发育及母体大小与幼体关系研究

采用组织学方法对日本新糠虾(Neomysis japonica)胚胎发育过程进行系统研究,并采用统计学方法分析了日本新糠虾母体体长与新孵幼体个数及新孵幼体体长间的相互关系.结果表明:日本新糠虾整个胚胎发育过程在育卵囊内完成,约需要8d(176-188h).其发育过程可分为3个阶段,细分为7个时期.以胚胎脱膜和蜕皮情况将胚胎发育划分:卵期、无眼幼体期和有眼幼体期3阶段,其中卵期阶段包括:受精卵期、囊胚期、原肠期和前无节幼体期;无眼幼体期阶段包括:无节幼体期和后无节幼体期;有眼幼体期阶段即为眼柄期.卵期约占整个胚胎发育时期的21.2%(40h);无眼幼体期是胚胎发育的主要时期,约占整个胚胎发育时期的48.9%(92h),其中肠、触角的分叉、心跳、眼点色素、腹部分节等都发生在此期;有眼幼体期约占整个胚胎发育时期的27.6%(52h).日本新糠虾母体体长与新孵幼体个数和新孵幼体体长间均有明显的正相关.这些结果不仅为丰富糠虾基础生物学内容提供理论资料,而且还可为糠虾的人工养殖提供参考.     

Developmentally regulated gene expression in Artemia: Histone gene expression in newly hatched larvae

The synthesis of histones and presence of histone mRNA sequences in embryos and larvae of the brine shrimp, Artemia, were investigated. Radiolabeling of proteins synthesized in vivo followed by electrophoretic and fluorographic analysis confirmed the prediction that histone synthesis is coordinated with the wave of DNA replication in newly hatched larvae. No histone synthesis occurs during development of encysted embryos. Hybridization of cloned Artemia histone gene DNA to total cell RNA indicated that dormant encysted embryos do not contain “masked” messenger RNA.     

Climbing by newly hatched larvae of the spotted stalk borer Chilo partellus to the top of sorghum plants

The biological impact of consumption and utilization of celery was examined for the generalist herbivore, Spodoptera exigua (Hübner). An analysis of leaves and petioles demonstrated that both plant parts contained high levels of water (>85%), but that leaves contained twice as much total organic nitrogen as petioles. Developmental and reproductive rates were significantly higher (P<0.01, t-test) for larvae fed on leaves. Penultimate and final instars consumed significantly more (P0.05, t-test) dry weight of plant material when fed petioles as opposed to leaves. Although growth rates were similar regardless of food source for penultimate instars, conversion of food to body weight was lower for larvae limited to petioles. In the final instar, both growth and conversion rates were lower for larvae fed petioles than for those given leaves. Thus, since larvae exhibit preferences for the nutritionally less suitable petioles during later larval stages, environmental factors other than nutrition must influence movement and distribution of S., exigua in celery.

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Résumé L'impact biologique de la consommation et de l'utilisation du céleri a été examiné sur un herbivore généraliste Spodoptera exigua Hübner. Une analyse de feuilles et de pétioles montre que ces deux parties de la plante ont une haute teneur en eau (>85%), mais que les feuilles contiennent deux fois plus d'azote organique total que les pétioles. Les taux de développement et de reproduction on été significativement plus élevés (<0,01 test t) pour les chenilles nourries sur feuilles. Les 2 derniers stades ont consommé significativement plus (P<0,05 test t) de poids sec de matière végétale en s'alimentant sur pétioles qu'en s'alimentant sur feuilles. Bien que les taux de croissance aient été voisins quel que soit l'aliment pour les avant-derniers stades, la conversion d'aliment en poids de corps était inférieure pour les chenilles ne consommant que des pétioles. Au dernier stade, tant les taux de croissance que de conversion des chenilles élevées sur pétioles étaient inférieurs à ceux des chenilles élevées sur feuilles. Ainsi, puisque les chenilles présentent une préférence pour les pétioles moins nutritifs au dernier stade larvaire, des paramètres écologiques autres que l'alimentation doivent influencer les mouvements et la distribution de S. exigua sur céleri.

     

The attraction of newly hatched codling moth (Laspeyresia pomonella) larvae to apple

Newly hatched codling moth (Laspeyresia pomonella) larvae are attracted to the skin of the apple cultivar Sturmer Pippin. In a closed test chamber the insects orientated and moved rapidly towards freshly cut apple skin. The outer skin of the fruit elicited a considerably stronger olfactory response than did the flesh. Dry filter papers treated with an external chloroform extract of whole apples were highly attractive to codling moth larvae. The behaviour of larvae in the presence of these odour sources has been observed and is manifest as a klinotaxis. The effect of the spatial separation of larvae and whole fruit, and the influence of air movement upon this, have also been investigated. The possible role of olfactory attraction in fruit location by newly hatched larvae is discussed.

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Zusammenfassung Frischgeschlüpfte Raupen des Apfelwicklers (Laspeyresia pomonella), die sich in einem geschlossenen Glasbehälter befanden, wurden zum Duft der Schale reifer Früchte des Sturmer Pippin-Apfels hingezogen Vor allem die Apfelschale, gleichgültig ob mit oder völlig ohne Fleisch, war für die Raupen sehr anziehend, während das mit reinem Apfelfleisch nur in geringem Maße der Fall war. Das weist eindeutig darauf hin, daß die anziehenden Faktoren hauptsächlich in der Schale selbst enthalten sein müssen.Ein Extrakt wurde hergestellt, indem ganze Äpfel 30 min in Chloroform eingetaucht wurden. Trockenes Filterpapier, das mit diesem Extrakt imprägniert war, wirkte für die Raupen ebenso anziehend wie frische Apfelschale. In beiden Fällen liefen die Raupen schnell direkt zur Duftquelle. Ihr Verhalten im Duftgradienten wurde beobachtet und als Klinotaxis eingestuft.Die Rolle des Abstandes der Raupe von der Frucht auf das Geruchsempfinden der Raupe in unbewegter Luft wurde geprüft. Es wurde festgestellt, daß die Raupen aus 1,5–2,0 cm Entfernung herbeigelockt werden können. Wurden ähnliche Experimente bei leichtem Luftzug gemacht, so änderte sich das Verhalten der Raupen dadurch nicht merklich.Daraus wird geschlossen, daß beim Auffinden der Frucht durch die eben ausgeschlüpften Raupen die Geruchsanziehung wohl eine größere Rolle spielen muß, zumal die meisten Eier ja nur wenige Zentimeter von der Frucht entfernt abgelegt werden. Dabei ist aber zu bedenken, daß auch andere Faktoren des Lebensraumes das Geruchsempfinden beeinflussen können.

     

Modification of responses of newly hatched snails by exposure to odors during development

Predatory marine snail larvae and embryos were exposed to preyodors (oyster, mussel and barnacle) during development. Whenjuvenile snails hatched they were tested by bioassay to determineeffects of this prior odor exposure. Juvenile snails were testedwith oyster, mussel and barnacle odors and with partially purifiedbarnacle odor of known attractiveness. Independent of priorodor exposure, only solutions containing barnacle odor wereattractive. Snails exposed during development to prey odorsnot in themselves attractive were more responsive to barnacleodors than snails that developed in barnacle odors. Snails notexposed to prey odors during development were intermediate intheir responsiveness. Field bioassays showed detectable attractantlevels in an environment containing barnacles. Attractant activitywas not detected in an environment where barnacles were absent.Responses of snails that developed in field odor conditionswere similar to those of snails that developed in the presenceof barnacles. Odor exposure during development is importantin determining future responses of these predatory snails toprey odors. ¹Duke University Marine Laboratory, Pivers Island, Beaufort,NC 28516, USA ²University of Miami RSMAS/MAC 4600 Rickenbacker Causeway, Miami,FL 33149, USA ³Suffolk University, Department of Biology, Beacon Hill, Boston,MA 02114, USA     

Embryonic development of the axial column in the little skate,Leucoraja erinacea

The morphological patterns and molecular mechanisms of vertebral column development are well understood in bony fishes (osteichthyans). However, vertebral column morphology in elasmobranch chondrichthyans (e.g., sharks and skates) differs from that of osteichthyans, and its development has not been extensively studied. Here, we characterize vertebral development in an elasmobranch fish, the little skate, Leucoraja erinacea , using microCT, paraffin histology, and whole‐mount skeletal preparations. Vertebral development begins with the condensation of mesenchyme, first around the notochord, and subsequently around the neural tube and caudal artery and vein. Mesenchyme surrounding the notochord differentiates into a continuous sheath of spindle‐shaped cells, which forms the precursor to the mineralized areolar calcification of the centrum. Mesenchyme around the neural tube and caudal artery/vein becomes united by a population of mesenchymal cells that condenses lateral to the sheath of spindle‐shaped cells, with this mesenchymal complex eventually differentiating into the hyaline cartilage of the future neural arches, hemal arches, and outer centrum. The initially continuous layers of areolar tissue and outer hyaline cartilage eventually subdivide into discrete centra and arches, with the notochord constricted in the center of each vertebra by a late‐forming “inner layer” of hyaline cartilage, and by a ring of areolar calcification located medial to the outer vertebral cartilage. The vertebrae of elasmobranchs are distinct among vertebrates, both in terms of their composition (i.e., with centra consisting of up to three tissues layers—an inner cartilage layer, a calcified areolar ring, and an outer layer of hyaline cartilage), and their mode of development (i.e., the subdivision of arch and outer centrum cartilage from an initially continuous layer of hyaline cartilage). Given the evident variation in patterns of vertebral construction, broad taxon sampling, and comparative developmental analyses are required to understand the diversity of mechanisms at work in the developing axial skeleton of vertebrates. J. Morphol. 278:300–320, 2017. © 2017 Wiley Periodicals, Inc.     

Egg weight variation in relation to egg mortality and starvation endurance of newly hatched larvae in some satyrid butterflies

Abstract. 1. Egg weights decrease over the oviposition period in all of the five satyrid butterflies that have been studied, viz Parage aegeria L., Lasiommata petropolitana F., L.maera L., L.megera L. and Lopingaachine Scop. However, within each species, no correlation was found between variation in egg weight and egg mortality in 30% relative humidity or the ability of newly hatched larvae to survive without food for 1–4 days. 2. Although egg weights of Papilio machaon L. were similar to the highest satyrid egg weights, newly hatched larvae of P.machaon showed significantly higher mortality after 1 day of starvation when compared to all of the satyrid larvae. This indicates that the capability of newly hatched larvae to endure starvation is not necessarily correlated with egg weight, and consequently that this character trait of satyrid larvae has been selected for (i.e. should be regarded as an adaptation). It is noteworthy that this ability of satyrid larvae to endure starvation is coupled with the habit of many satyrid butterflies not to deposit their eggs directly on the larval host plants. 3. In 30% relative humidity, egg mortality of L.achine was 100% and that of P.aegeria 29.2%, whereas that of the three Lasiommata spp. was significantly lower. At 100% relative humidity egg mortality in L.achine dropped to 8%. Since egg weights are higher in L.achine than in the other four satyrids this indicates that egg resistance to desiccation is not necessarily correlated with egg size (as might be expected due to the area to volume ratio which is negatively correlated with egg size). Thus the resistance to desiccation which is found in the three Lasiommata spp. should be regarded as an adaptation to the habit of these three butterflies to deposit their eggs in relatively dry microhabitats. This resistance to desiccation is not found in eggs of the two forest-dwelling satyrids P.aegeria and L.achine which lay their eggs in microhabitats where the relative humidity is high.     

Embryonic and morphological development of larvae and juveniles of the Amberjack,Seriola dumerili

Embryonic and morphological development of larvae and juveniles of the amberjack,Seriola dumerili Risso, are described using specimens raised at Yaeyama Station (Ishigaki Island, Okinawa Pref.), Japan Sea Farming Association. The specimens obtained from brood fish (3 females, 3 males) were treated with gonadotropin and spawned on 6th of April 1987. The eggs of amberjack are pelagic, spherical in shape and 1.01–1.17 mm in diameter. The yolk is roughly segmented and has a single oil globule 0.22–0.24 mm in diameter. The perivitelline space is narrow. During development, a few melanophores and no xanthophores were observed on yolk. Hatching took place 35 hrs. 15 min. after spawning out at temperatures 23.1–23.7°C. The newly hatched larvae were 2.84–3.04mm in TL with 27 (13+14) myomeres and an oil globule anteriorly situated beyond the head. 3 days after hatching 4.00 mm TL, the mouth opened. 10 days after hatching 4.26 mm TL, small denticles appeared on the margin of the upper jaw and there were 1 anterior and 2 posterior preopecular spines. At 5.96mm TL, notochord was slightly flexed. Caudal, dorsal and anal fins with rudiments of rays appeared at 8.00 mm TL. The specific numbers of all fin rays and spines were obtained in a juvenile 9.60 mm TL. In a juvenile 34.25 mm TL, 54 days after hatching, the characteristic brown band of amberjack had appeared on head. Some notable changes in relative growth were observed at 5 mm and 15 mm in TL.     

Attraction of newly hatched codling moth larvae (Laspeyresia pomonella) to synthetic stereo-isomers of farnesene

Newly hatched Laspeyresia pomonella larvae were attracted to only two of six synthetic stereo-isomers of the acyclic sesquiterpene farnesene. These were (E,E)-α-farnesene and (Z,E)-α-farnesene which together comprise a natural attractant for the insect. Two other α-isomers and two β-isomers had no influence on larval behaviour. The activity of isomers is correlated with their molecular shape.     

Embryonic development,larvae and juvenile of elkhorn sculpin,Alcichthys alcicornis

The eggs ofAlcichthys alcicornis were spawned in tank at the laboratory and reared for the studies of embryonic, larval and juvenile development. This species takes place entosomatic fertilization, and females spawn fertilized eggs after copulation. The eggs are demersal and adhesive, released as a clump forming a thin layer on the bottom of tank. There was no significant difference in embryonic development between this species and other oviparous teleostean species. Hatching occurred between 17 and 18 days after spawning at a mean water temperature of 8.5?C. The newly hatched larvae averaged 4.44 mm in body length (BL). The larvae attained to post-larval stage at 5.80 mm BL, and juvenile stage at 10.2 mm BL. A specific feature of the post-larvae was the appearance of three lines of the melanophores on the caudal part of fin fold. Carotenoid first appeared on the nape at 8.70 mm BL, heavily emerged beyond 12.9 mm BL, and turned up on the back also beyond 15.2 mm BL. Scales on the lateral line were completed by 18.5 mm BL. Three pairs of flaps were observed on the dorsal surface of the head at 37.0 mm BL. External features of adult specimens are almost completed by 52.0 mm BL, yet the tip of the first preopercular was not branched but remained simple.     

Spontaneous discrimination of possible and impossible objects by newly hatched chicks

Four-month-old infants can integrate local cues provided by two-dimensional pictures and interpret global inconsistencies in structural information to discriminate between possible and impossible objects. This leaves unanswered the issue of the relative contribution of maturation of biologically predisposed mechanisms and of experience with real objects, to the development of this capability. Here we show that, after exposure to objects in which junctions providing cues to global structure were occluded, day-old chicks selectively approach the two-dimensional image that depicted the possible rather than the impossible version of a three-dimensional object, after restoration of the junctions. Even more impressively, completely naive newly hatched chicks showed spontaneous preferences towards approaching two-dimensional depictions of structurally possible rather than impossible objects. These findings suggest that the vertebrate brain can be biologically predisposed towards approaching a two-dimensional image representing a view of a structurally possible three-dimensional object.     

Tissue-Specific antioxidant profiles and susceptibility to lipid peroxidation of the newly hatched chick

The hatching process is characterized by a range of adaptive changes, and a newly hatched chick is considered as an intermediate stage between prenatal and postnatal development. The aim of the present study was to evaluate the characteristic relationships between tissue-specific fatty acid composition and antioxidant protection in newly hatched chicks. Liver, yolk sac membrane, heart, kidney, lung, and four brain regions (cerebrum, cerebellum, stem, and optic lobes) were collected. Fatty acid composition of total lipids and phosphoglycerides, α-tocopherol, lutein, ascorbic acid, reduced glutathione, and the activities of Mn-and Cu,Zn-superoxide dismutase (SOD) and Se-dependent and non-Se-glutathione peroxidase (GSH-Px), and catalase (CAT) were determined. The levels of Fe, Cu, Zn, and Mn as well as tissue susceptibility to lipid peroxidation were also studied. The tissues of the newly hatched chick showed distinctive features in fatty acid profiles, antioxidant accumulation, and susceptibility to lipid peroxidation. The brain clearly displayed the greatest susceptibility to spontaneous and Fe-stimulated lipid peroxidation, was highly unsaturated and contained very low levels of vitamin E, no detectable carotenoids, low GSH-Px, and low CAT activity. At the same time, the brain was characterized by high ascorbic acid concentration and comparatively high SOD activity. It was suggested that in postnatal development, antioxidant enzymes presumably play the major role in antioxidant protection of the chick tissues.