An electrophoretic study of the systematic relationships of some closely related goby species (Pisces, Gobiidae)

An electrophoretic study of genetic variation at 31 loci in each of nine closely related gobiid species was carried out in order to assess their systematic relationships. The species used were: Pomatoschistus canestrinii, P. lozanoi, P. marmoratus, P. microps, P. minutus, P. norvegkus, P. pictus, Knipowitschia caucasica, Neogobius melanostomus. Genetic distances ( D ) and identities ( I ) were calculated by Nei's method for all 36 pairwise comparisons and dendrograms were constructed.
The results show that the very similar and cross-fertile species pair, P. lozanoi and P. minutus , have the highest I value; P. norvegkus has high I values with both species. Pomatoschistus marmoratus and P. microps also display high genetic similarity with each other. The remaining Pomatoschistus species and Knipowitschia caucasica are broadly and moderately equidistant from each other and from the five species refferred to above, while Neogobius melanostomus is considerably more distant from all other species.
These findings essentially agree with the pattern of relationships established using classical taxonomic approaches. However, the observation that Knipowitschia caucasica is as similar to Pomatoschistus spp. as the latter are to each other suggests that the generic distinction of Knipowitschia could usefully be reconsidered.     

Respiratory responses of Oreochromis niloticus (Pisces, Cichlidae) to environmental hypoxia under different thermal conditions

The oxygen uptake ( V O₂), breathing frequency ( f _R), breath volume ( V _S.R), gill ventilation ( V G) and oxygen extraction (%) from the ventilatory current of four groups of Oreochromis niloticus during graded hypoxia were measured under the following acclimation temperatures: 20. 25. 30 and 35°C. The critical oxygen tensions ( P O₂), determined from V O₂ v. P O₂ of inspired water at each experimental temperature were, respectively. 19±1±3±1. 18±0±4±9, 29±7± 4±1 and 30±2± 0.6 mmHg. The f _R remained nearly constant during the reductions of O₂ at all the temperatures studied. V G increased discretely from normoxic levels until the P O₂ was reached, below which it assumed extremely high values (17-fold higher or more). The increases observed in V G resulted, at all the acclimation temperatures, in an elevation in V _S.R rather than in f _R. The extraction of O₂ decreased gradually from normoxia until the P O₂ was reached, below which an abrupt reduction of extraction was recorded, except at 35°C when fish showed a gradual reduction in extraction just below the tension of 80 mmHg.     

Two new species of the genusAmblyeleotris (Pisces: Gobiidae) from the Ryukyu Islands,Japan

Two new shrimp-associated gobies,Amblyeleotris yanoi sp. nov. andA. masuii sp. nov. are described on the basis of specimens from Iriomote-jima Island and Okinawa-jima Islands, Okinawa Prefecture, Japan.A. yanoi is distinguished from other members of the genus by the combination of the following characters: 14 anal fin soft rays, 19 pectoral fin rays, 97–103 longitudinal scales, a candle flame-shaped marking on the caudal fin, a very low membrane connecting the pelvic fins and absence of a ventral frenum.A. masuii differs from all other congeners by having 92–97 longitudinal scales, the length of the interpelvic connecting membrane relative to the longest pelvic fin ray (0.43–0.66), black blotches on the sides of the chin, and blue spots on the opercle and preopercle.     

Genetic and biogeographic relationships of the racer goby Neogobius gymnotrachelus (Gobiidae: Teleostei) from introduced and native Eurasian locations

The racer goby Neogobius gymnotrachelus , along with several other neogobiin fishes, has been spreading north and west from its native Ponto-Caspian range for the past two decades via shipping and canals. It has been predicted as a likely future invader of the North American Great Lakes, where it would join its neogobiin relatives – the round and freshwater tubenose gobies. The present study is the first to analyse the population genetic and biogeographic relationships of the racer goby, establishing a baseline to aid interpretation of its future spread patterns and likely donor-recipient population relationships. The mitochondrial DNA cytochrome b gene was sequenced from representative areas of the racer goby's range, including rivers of the northern Black Sea and areas of spread upstream in the Danube River and outside the Ponto-Caspian region to the Vistula River in Poland. Results discerned nine haplotypes, with few shared among drainages of native rivers and most sites housing unique alleles. Racer goby populations significantly diverged among watersheds, supporting historic low migration and little non-anthropogenic gene flow. The Dnieper River was identified as a likely donor source for the Vistula River colonization, where appreciable variability suggests a relatively large number of founding genotypes.     

Respiratory responses to hypoxia in relation to mode of life of two erythrinid species (Hoplias malabaricus and Hoplias lacerdae)

Predominantly, Hoplias malabaricus inhabits stagnant O₂ poor environments, whereas Hoplias lacerdae occurs in well-aerated streams. The present study evaluates the influence of mode of life on O₂ uptake and gill ventilation in equally-sized (300 g) specimens of this genus at 25° C. Comparing the species, H. lacerdae was characterized by the highest O₂ uptake and gill ventilation combined with a relatively higher cost of breathing and a lower O₂ extraction. Both species substantially increased ventilation in response to hypoxia with the difference that H. malabaricus exclusively augmented tidal volume, whereas H. lacerdae also increased breathing frequency.     

Agonistic behaviour and control of access to hiding places in two intertidal blennies, Lipophrys pholis and Coryphoblennius galerita (Pisces: Blenniidae)

In this study we investigated the relationships between dominance rank and access to shelters in captive groups of Lipophrys pholis and Coryphoblennius galerita, as well as the effects of group size and shelter availability. Dominance rank was strongly correlated with size in juvenile L. pholis and with sex and size in adult C. galerita, males being dominant over females of similar size. Access to shelters was significantly correlated with dominance rank. For both species, most interactions occurred out of shelters. Direct disputes over shelters were always initiated by the dominant fish and the initiator was always the winner. The rate of aggression per fish per unit time decreased with an increase in the number of fish in L. pholis but not in C. galerita. No significant differences were found in groups differing in the number of shelters. C. galerita showed a higher rate of agonistic interactions and a higher proportion of overt aggression than L. pholis. It is suggested that one of the functions of agonistic interactions in these fishes is the control of a set of shelters, in the network of pathways used by each individual within its home range, minimising the time required to hide in case of danger. Received in revised form: 29 January 2001 Electronic Publication     

Survival capacity of two species of Cybocephalus (Coleoptera: Cybocephalidae) under temperature and humidity extremes

A comparison was made between the survival capacity of two species of Cybocephalus found in different regions in Israel. The first, C. nigriceps (Sahlberg), is prevalent in the Arava, a very hot and dry region; the second, C. micans Reitter, is widespread particularly in the coastal plain, a cooler and more humid region.The third-stage larva, pupa and adult were tested at temperatures ranging between 43 and 47° C and at relative humidities of 10, 32.5 and 75%. In nearly all cases high temperature was the main factor affecting survival. C. nigriceps was more resistant to temperature and humidity extreme than C. micans. In both species the adult was the most sensitive of the three stages tested. The pupa of C. micans was more resistant than the third-stage larva.

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Résumé La capacité de survie à des conditions extrêmes de température a été étudiée chez deux espèces de Cybocephalus, en vue d'expliquer leur répartition dans différentes régions d'Israel.La première: C. nigriceps (Sahlberg) est trouvée dans l'Arava, une région extrêmement chaude et aride où elle est un prédateur de la Cochenille du Palmier Dattier (Parlatoria blanchardi), tandis que la seconde, C. micans Reitter, est particulièrement répandue dans la plaine côtière qui est moins chaude et plus humide et où elle s'attaque à diverses Diaspines des citrus (Parlatoria pergandii, P. cinerea et Aonidiella aurantii).Les stades de ces insectes sur lesquels il a été expérimenté furent la larve du troisième âge, la pupe et l'adulte. Les expériences ont été conduites à des températures comprises entre 43 et 47° C, et à des humidités relatives de 10%, 32.5% et 75%. Dans presque tous les cas il s'est avéré qu'une haute température est le facteur principal affectant la survie. C. nigriceps s'est montré plus résistant aux extrêmes de température et d'humidité que C. micans. Dans les deux expèces, l'adulte est plus sensible que les deux autres stades examinés. La pupe de C. micans semble plus résistante que la larve du troisième âge.

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Contribution from the Volcani Institute of Agricultural Research, Bet Dagan, Israel. 1971 Series; No. 1848-E.     

Chemoreception in four species of water mites (Acari: Hydrachnida): behavioural and morphological evidence

Silver nitrate staining of the solenidial and eupathidial sensilla on the palpi, tarsi and tibiae of legs I and II of Arrenurus acutus, Geayia ovata, Mideopsis reelfootensis and Albia caerulea, along with ultrastructural studies, showed that these setae have a porous shaft cuticle. These setae are hollow and contain dendrites in their lumens and more than one neuron is associated with each setae. Behavioural experiments supported the involvement of these sensilla in the perception of chemical cues from prey and sexual partners.     

Chemoreception in four species of water mites (Acari: Hydrachnida): behavioural and morphological evidence

Silver nitrate staining of the solenidial and eupathidial sensilla on the palpi, tarsi and tibiae of legs I and II of Arrenurus acutus, Geayia ovata, Mideopsis reelfootensis and Albia caerulea, along with ultrastructural studies, showed that these setae have a porous shaft cuticle. These setae are hollow and contain dendrites in their lumens and more than one neuron is associated with each setae. Behavioural experiments supported the involvement of these sensilla in the perception of chemical cues from prey and sexual partners.     

Temperature dependence of development rate and adult size in Drosophila species: biophysical parameters

Adult size in Drosophila results from the ratio of the rate of biomass increase and the rate of differentiation, both rates being temperature sensitive. Data on rates and size are collected in two tropical and two temperate Drosophila species; differentiation rate is higher in the two tropical species, growth rate differs between the large and small species of similar climatic origin. A biophysical model is used to evaluate the temperature dependence of adult size in Drosophila. The model is based upon the Sharpe–Schoolfield equation connecting enzyme kinetics and biological rates. Temperature sensitivities of growth rate, development time, and wing and thorax size are characterized by biophysical parameters. The biophysical parameter indicating trait specific temperature sensitivity is lower in tropical species than in temperate species, both for growth rate and for differentiation rate. In the larger species of a climate pair, thorax size and wing size prove to differ in pattern of temperature dependence; in the smaller species of a geographical pair, thorax size and wing size have identical patterns of temperature dependence.     

Structures and immunolocalization of Na+, K+ -ATPase, Na+ /H+ exchanger 3 and vacuolar-type H+ -ATPase in the gills of blennies (Teleostei: Blenniidae) inhabiting rocky intertidal areas

The structure and immunolocalization of the ion transporters Na(+) ,K(+) -ATPase (NKA), Na(+) /H(+) exchanger (NHE3) and vacuolar-type H(+) -ATPase (VHA) were examined in the gills of teleosts of the family Blenniidae, which inhabit rocky shores with vertical zonation in subtropical seas. These features were compared among the following species with different ecologies: the amphibious rockskipper blenny Andamia tetradactylus, the intertidal white-finned blenny Praealticus tanegasimae and the purely marine yaeyama blenny Ecsenius yaeyamaensis. Light and electron microscopic observations indicated that thick gill filaments were arranged close to each other and alternately on two hemibranches of a gill arch in the opercular space of A. tetradactylus. Many mucous cells (MC) and mitochondrion-rich cells (MRC) were present in the interlamellar regions of the gill filament. An immunohistochemical study demonstrated that numerous NKA, NHE3 and some VHA were located predominantly on presumed MRCs of gill filaments and at the base of the lamellae. Analyses using serial (mirror image) sections of the gills indicated that only a few NKA immunoreactive cells (IRC) were colocalized with VHA on some MRCs in the filaments. In the gills of P. tanegasimae, NKA- and NHE3-IRCs were observed in the interlamellar region of the filaments and at the base of the lamellae. VHA-IRCs were located sparsely on the lamellae and filaments. In the gills of E. yaeyamaensis, the lamellae and filaments were thin and straight, respectively. MCs were located at the tip as well as found scattered in the interlamellar region of gill filaments. NKA-, NHE3- and VHA-IRCs were moderately frequently observed in the filaments and rarely on the lamellae. This study shows that the structure and distribution of ion transporters in the gills differ among the three blennid species, presumably reflecting their different ecologies.     

Oxygen consumption of Astyanax fasciatus (Characidae,Pisces): a comparison of epigean and hypogean populations

Synopsis The standard and routine oxygen consumptions of Astyanax fasciatus from one surface population (Rio Teapao) and three cave populations (Chica, Micos and Pachon caves: sAnoptichthys jordani, the Micosfish and Anoptichthys antrobius) were determined individually over 24 hours by the use of a flow-through respirometer and polarographic oxygen electrodes. The phylogenetically oldest Pachon fish had a significantly lower standard metabolic rate (0.230 ± 0.036 mg O₂ g^-1 h^-1) than the epigean Teapao fish, the hybrid Chica fish and the phylogenetically younger Micos fish (0.314 ± 0.081 mg O₂g-^-1h^-1, 0.284 ± 0.048 mg O₂g^-1h^-1, 0.277 ± 0.063 mg O₂g^-1h^-1). No significant differences could be determined among the latter three populations. A significant difference in routine metabolic rate existed only between the Pachon fish (0.309 ± 0.0.56 mg O₂g^-1h^-1) and the Teapao fish (0.415 ± 0.071 mg O₂g^-1h^-1). The Chica fish (0.356 ± 0.084 mg O₂g^-1h^-1) and the Micos fish (0.355 ± 0.080 mg O₂ g^-1h^-1) could not be separated from either the Teapao or the Pachon fish, but a decreasing trend from the surface population through the Chica and the Micos to the Pachon population was obvious. During a starvation period of 29 days the metabolic rate of epigean Teapao and hypogean Pachon fish decreased significantly by 32.5% and 34.8% (standard oxygen consumption rate) and 27.5% and 28.2% (routine oxygen consumption rate), respectively. Body mass loss during the starvation period was 16.3% for the Teapao fish and 9.5% for the Pachon fish.     

Influence of diet on growth,food retention time,and gill ventilation rate of nymphs of Cloeon sp. (Ephemeroptera: Baetidae)

Early instar nymphs of the mayfly, Cloeon sp. were kept on an algal or a detrital diet at 20 ± 1 °C in the laboratory. A control group was not given any food. Nymphs kept on algae showed significantly (P = 0.001) higher growth both in terms of length and biomass than for those kept on detritus. None of the nymphs given algae or detritus died during the experiment, and 40 per cent of those fed algae and 20 per cent fed detritus reached maturity by the termination of the experiment. Food retention time as well as gill ventilation rate of nymphs feeding on algae were significantly (P = 0.001) higher than those feeding on detritus. It is probable that these two factors largely enabled the nymphs to survive as well as to grow and reach maturity, though relatively slowly, solely on a detrital diet. However, algae was clearly shown to be a superior food resource for Cloeon sp. nymphs.     

阿里山潜蝇茧蜂的羽化率及死亡率与储存温度的拟合关系

本文通过室内模拟低温,研究了阿里山潜蝇茧蜂雌成蜂、9日龄蛹的致死中温度和线性拟合。结果表明,在不同温度下雌蜂的砜分别为4℃下6．6149天,7℃下8．1235天,100℃下9．6161天,13℃下5．0257天,且在所有温度下都有死亡率陡升过程。9日龄蛹在不同温度下的LT50分别为4℃下8．4172天,7℃下8．1235天,10℃下13．9949天,13℃下18．4107天;同一温度下的蛹羽化率与保存天数的关系适宜用二次方程拟合。研究认为蛹的耐寒性强于雌成蜂,可以作为低温保存的虫态。     

Growth temperature influences the underlying components of relative growth rate: an investigation using inherently fast- and slow-growing plant species

We examined the effect of growth temperature on the underlying components of growth in a range of inherently fast‐ and slow‐growing plant species. Plants were grown hydroponically at constant 18, 23 and 28 °C. Growth analysis was conducted on 16 contrasting plant species, with whole plant gas exchange being performed on six of the 16 species. Inter‐specific variations in specific leaf area (SLA) were important in determining variations in relative growth rate (RGR) amongst the species at 23 and 28 °C but were not related to variations in RGR at 18 °C. When grown at 18 °C, net assimilation rate (NAR) became more important than SLA for explaining variations in RGR. Variations in whole shoot photosynthesis and carbon concentration could not explain the importance of NAR in determining RGR at the lower temperatures. Rather, variations in the degree to which whole plant respiration per unit leaf area acclimated to the different growth temperatures were responsible. Plants grown at 28 °C used a greater proportion of their daily fixed carbon in respiration than did the 18 and 23 °C‐grown plants. It is concluded that the relative importance of the underlying components of growth are influenced by growth temperature, and the degree of acclimation of respiration is of central importance to the greater role played by NAR in determining variations in RGR at declining growth temperatures.     

Diurnal activity, temperature responses and endothermy in three South American cicadas (Homoptera: Cicadidae: Dorisiana bonaerensis, Quesada gigas and Fidicina mannifera)

1. 1. Measurements of body temperature (T_b) in the field demonstrated that endothermic cicadas regulate T_b by behavioral mechanisms as well as by endogenous heat production.

2. 2. The T_b of endothermically active cicadas without access to exogenous heat is approximately the same as the T_b of basking cicadas.

3. 3. Dorisiana bonaerensis (Berg) and Quesada gigas (Olivier) raise T_b in the field with the heat produced in flight.

4. 4. The thermal responses of a particular species are related to its activity patterns and habitat.

5. 5. Endothermy in cicadas may serve to uncouple reproductive behavior from environmental constraints; to circumvent possible thermoregulatory problems; to permit the utilization of habitats unavailable to strictly ectothermic cicadas; to reduce predation; and to optimize broadcast coverage and sound transmission.

     

Serum parameters of Adriatic sturgeon Acipenser naccarii (Pisces: Acipenseriformes): effects of temperature and stress

Data on the concentrations of some blood constituents of captive Adriatic sturgeon, Acipenser naccarii, a primitive bony fish, are reported. Serum osmolality, Na⁺, K⁺, Cl⁻, Ca²⁺, cortisol, glucose and total protein concentrations were measured. The effects of anaesthesia, temperature, crowding and prolonged handling stress were tested on a group of 12 4-year-old sturgeons sampled repeatedly. The anaesthetic dose of MS 222 (140 mg l⁻¹) induced significant osmolality elevation in the sturgeon. After exposure to colder temperature (17 versus 25°C), cortisol and Cl⁻ concentrations significantly decreased. The cultured sturgeon did not seem susceptible to crowding and prolonged handling stress, since neither the serum cortisol and glucose levels nor the other blood parameters were affected by these stressors. Results are compared with the few available data on other chondrostean fish and with those on teleosts.