Depth telemetry from the sixgill shark,Hexanchus griseus,at Bermuda

Synopsis Transmitters were attached to two female sixgill sharks, Hexanchus griseus, which were followed in course and depth for periods of 4 and 2 days. The sharks swam slowly (10 to 20 cm s^-1) and continuously, generally moving parallel to the bottom contours within a limited (less than 10 km long) area. The greatest depth was an excursion to 1500 m, but otherwise the sharks remained near the bottom at depths ranging from 600 to 1100 m.     

SATELLITE-MONITORED MOVEMENTS AND DIVE BEHAVIOR OF A BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS) IN TAMPA BAY, FLORIDA

An adult, female bottlenose dolphin ( Tursiops trucncatus ) was radio tagged and monitored via satellite-based Argos receivers for 25 d from 28 June to 23 July 1990, in Tampa Bay, Florida. A total of 794 transmissions were obtained during 106 satellite passes. A mean of 3.9 (SE = 0.24) locations/day were determined by Service Argos and showed the animal remained in the bay, usually close to the southeastern shore. The dolphin moved at least 581 km at a minimum mean speed of 1.2 (SE = 0.1) km/h. Data from 63, 922 dives were recorded. The animal spent an average of 87.1 (SE = 0.6)% of the time submerged, with a mean dive duration of 25.8 (SE = 0.5) sec. Mean dive duration differed significantly between four periods of the day, as did the mean percent of time spent submerged. During the early morning the animal spent more time at the surface, averaged shorter dives, and was submerged less than other times of day. This is the first study to demonstrate die1 dive cycles in a bottlenose dolphin. Four months after tag loss, the dolphin was photographed with no evidence of necrosis or disfigurement of the dorsal fin. Satellite telemetry was demonstrated as an effective means of documenting the movements and dive behavior of a small inshore cetacean.     

The pollination ecology ofBletilla striata (Orchidaceae)

Anthecological observations of an orchidBletilla striata were carried out in Kobe, Japan. The purplish pink flowers were visited by 26 species of insects belonging to Hymenoptera, Diptera and Lepidoptera, although the flower did not offer food rewards of any kind. Candidates for pollination were seven species of aculeate Hymenoptera with a body size that well fitted the space in between the column and labellum. The most effective candidate was the male of the longhorn beeTetralonia nipponensis, judging from its abundance and legitimate intrafloral behavior. The female ofT. nipponensis and the other six species also contributed to promote out-crossing, but to a lesser extent than the maleT. nipponensis, since they occasionally exhibited illegitimate intrafloral behaviors for pollination and also, their flower visitation rate was lower.     

高苯丙氨酸血症大鼠脑内单胺类递质的研究

以3d龄Sprague-Dawley大鼠腹腔注射苯丙氨酸(Phe)诱导高苯丙氨酸血症,荧光法测定大脑皮层及其突触体中去甲肾上腺素(NE)、多巴胺(DA)和5-羟色胺(5-HT)含量;Y型电迷宫法测其学习记忆能力.结果显示:高苯丙氨酸血症大鼠大脑皮层NE、DA及5-HT含量降低38.6%～67.4%,突触体中NE、DA和5-HT含量降低51.9%～70.2%,学习记忆能力明显低于对照组.结果提示,苯酮尿症智力障碍可能与大脑皮层及其突触体中某些单胺类递质含量降低相关.     

Host related factors affecting oviposition behavior in Brachymeria intermedia

Some behavioral and physical defenses of Lymantria dispar (L.) pupae are described. It was found that the layer of webbing surrounding pupae significantly reduced oviposition rates in the pupal parasitoid Brachymeria intermedia (Nees) (Hymenoptera, Chalcididae). The reasons for this reduction and consequent parasitoid responses were investigated. The role of these behaviors in this host parasitoid relationship are discussed.

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Résumé Le comportement défensif des chrysalides de Lymantria dispar L. consiste en cambrage et en tournoiement. Les chrysalides encoconées étaient plus sensibles aux stimuli tactiles que celles qui ont été extraites des cocons. Brachymeria intermedia Nees avait moint de succès dans l'insertion complète de la tarière dans des chrysalides encoconées qu'extraites, car elles devenaient empêtrées dans le cocon quand la chrysalide se défendait. Il y avait différentes réponses du parasitoïde à l'empêtrement. Elles comprenaient l'abandon de l'attaque par un départ, la remise en selle sur l'hôte, la morsure à travers les fils du cocon, l'attaque d'un hôte voisin, le repos ou la toilette. Les taux d'insertion de la tarière pouvaient être augmentés par l'élimination artificielle de quelques fils. La durée des opérations était plus courte sur les chrysalides plus petites. La discussion a porté sur l'importance de ces comportements sur les relations de ces parasitoïdes avec leurs hôtes.

     

Phase behavior of isolated photoreceptor membrane lipids is modulated by bivalent cations

The phase behavior of isolated photoreceptor membrane lipids is further investigated by ³¹P-NMR, in view of earlier discrepant results [(1979) Biochim. Biophys. Acta 558, 330–337; (1982) FEBS Lett. 124, 93–99]. We present evidence that the discrepancy is due to bivalent cations. When resuspended in aqueous media at neutral pH in the absence of bivalent cations, the isolated photoreceptor membrane lipids largely adopt the bilayer configuration. However, upon addition of such cations (Ca²⁺ Mg²⁺) or when resuspended in their presence, the formation of other phases (hexagonal H_II, lipidic particles) results. The rate of this transition depends on cation concentration and temperature. The transition is not easily reversed by addition of EDTA. Implications with regard to photoreceptor membrane structure and function need further study.     

The reproductive behaviour ofAequidens vittatus (Pisces,Cichlidae) in Surinam,South America

Synopsis The behaviour of free-living pairs ofAequidens vittatus was observed in Surinam, South America. An ethogram of breeding behaviour is presented, based on those observations and on aquarium-held fish. This is a biparental, substrate-guarding species that spawns on a movable platform. Sexual differentiation of parental roles was more pronounced when the young were in the embryonic interval than when they were mobile juveniles. Females spent more time near their brood, attacked juvenile conspecifics more often, and fanned and mouthed embryos more than males did. Males were more involved than females in territorial spacing of pairs. The movable spawning leaf provides support for eggs on detritus substrate and may also provide protection against predators and rapid water level changes.     

CULTURE STUDY OF REPRODUCTIVE CYCLES AND SYSTEMATICA IN MOUGEOTIA TRANSEAUI (CHLOROPHYTA)1,2

Asexual and sexual reproductive cyries are described and illustrated for a cultured homothallic strain of Mougeotia transeaui Collins. Reproduction is by aplanospores and zygospores. Aplanospore formation precedes zygospore formation and continues longer with regreening of older cultures occurring regularly from precocious germination of aplanospores. Aplanospores typically form when most of the protoplast moves into the central swollen region of a cell and two new cross walls form to delimit an aplanosporangium. Conjugation is scalariform without the movement and fusion of well-organized gametes. During zygospore maturation, three new cross walls form in the receptive gametangium and conjugation tube to produce a zygosporangium.