Presence, biotransformation and effects of sulfophenylcarboxylic acids in the benthic fish Solea senegalensis

The presence of linear alkylbenzene sulfonates (LAS) and their degradation intermediates, sulfophenylcarboxylic acids (SPCs), with concentrations up to 100 ppb has been found in surface waters taken from the estuary of the river Guadalete (Cádiz, SW of Spain). Higher concentrations were found at the sampling site located adjacent to the discharge outlet of a wastewater treatment plant (WWTP). The concentrations decreased downstream to a few ppb as a result of dilution, sorption, and degradation processes, which were taking place along the estuary. Once the presence of both xenobiotics was confirmed in the environment, an in vivo assay was conducted to study their biotransformation and effects in the benthic fish Solea senegalensis. A flow-through system was employed, consisting of an exposure phase (120 h) with environmental levels of the surfactant (200, 500 and 800 microg/L of 2?C(10)LAS), followed by a depuration stage (72 h). The generation of SPCs has been quantified during these phases in both water and fish, with LAS biotransformation shown in all cases. The antioxidant enzymes catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), the phase II enzyme glutathione S-transferase (GST), and the phase III acid and alkaline phosphatases (AcP, ALP) were also estimated and utilized as biomarkers.     

Cladocerans under conditions of small river damming by man and beavers

In beaver ponds, the species diversity, abundance, biomass, and production of cladocerans and the amount of food consumed by them have increased and the composition of dominant species has changed as compared to those in the stretches of small rivers with running water or dammed by man. The stimulating effect of water from a beaver pond has been confirmed in laboratory experiments. The average number of juvenile Ceriodaphnia affinis produced by one female was considerably greater in this water than in the water from flowing and dammed (by man) river stretches.     

Specific features of phenetic structure of the terrestrial snail <Emphasis Type="Italic">Cepaea vindobonensis</Emphasis> (Pulmonata; Helicidae) in urbanized and natural populations

The phenetic structure of natural and urbanized populations of the terrestrial snail Cepaea vindobonensis has been studied with respect to polymorphism in the shell-band color and pattern. It is noted that C. vindobonensis snails populating different artificial habitats in the city of Nikolaev and its suburbs are characterized by a higher level of both intra-and interpopulation diversity with respect to the type of this polymorphism. In addition, urban populations show a very wide range of variation in the frequencies of particular morphs or their groups. Conversely, natural populations are characterized by a more uniform frequency structure with respect to polymorphism of the shell banding pattern.     

Insights into the role of age and social interactions on the sexual attractiveness of queens in an eusocial bee, <Emphasis Type="Italic">Melipona flavolineata</Emphasis> (Apidae,Meliponini)

The attraction of sexual partners is a vital necessity among insects, and it involves conflict of interests and complex communication systems among male and female. In this study, we investigated the developing of sexual attractiveness in virgin queens (i.e., gynes) of Melipona flavolineata, an eusocial stingless bee. We followed the development of sexual attractiveness in 64 gynes, belonging to seven age classes (0, 3, 6, 9, 15, 18 days post-emergence), and we also evaluated the effect of different social interactions (such as competition between queens and interactions with workers) on the development of attractiveness in other 60 gynes. We used the number of males that tried to mate with a focal gyne as a representative variable of its sexual attractiveness. During the essays, each gyne was individually presented to 10 sexually mature males, and during 3 min, we counted the number of males that everted their genitalia in response to the presence of a gyne. Here, we show that M. flavolineata gynes are capable to (i) maintain their sexual attractiveness for long periods through adult life, (ii) they need a minimum social interaction to trigger the development of sexual attractiveness, and (iii) that gynes express this trait only within a social context. We conclude that the effective occurrence of matings is conditional on potential social interactions that gynes experienced before taking the nuptial flight, when they are still in the nest. These findings bring insights into the factors determining reproductive success in social insects.     

Sexual differences in food preferences in the white stork: an experimental study

Sex differences in the foraging ecology of monomorphic species are poorly understood, due to problems with gender identification in field studies. In the current study, we used experimental conditions to investigate the food preferences of the white stork Ciconia ciconia, an opportunistic species in terms of food, but characterised by a low level of sexual dimorphism. During a 10-day experiment, 29 individuals (20 females and 9 males) were studied by means of a ‘cafeteria test’ in which the storks’ diet consisted of mammals, birds, fish, amphibians, insects and earthworms. The storks preferred food characterised by high calorific and protein values such as mammals, birds and fish. Sexes differed strongly in their preferences; males preferred mammals, whereas females preferred birds. Moreover, females consumed insects and earthworms less often than males. Interestingly, males spent significantly less time foraging than females. We have demonstrated that the white stork exhibits clear sexual differences in food preferences which are mostly attributable to differences in parental duties, physiology and anatomy.     

Bone histology sheds light on the nature of the “dermal armor” of the enigmatic sauropod dinosaur <Emphasis Type="Italic">Agustinia ligabuei</Emphasis> Bonaparte, 1999

Agustinia ligabuei is an Early Cretaceous sauropod dinosaur from the northwest of Patagonia that is currently the topic of debate with respect to its phylogenetic position and atypical dermal armor. The presence of four morphotypes of laminar and transversely elongated putative osteoderms was used to consider Agustinia as an armored sauropod. Regarding the different hypotheses about the identity of the bony structures of Agustinia (e.g., osteoderms, cervical or dorsal ribs, hypertrophied elements), a comparative histological analysis has been carried out. Histological evidence is presented herein and reveals that none of the morphotypes of Agustinia shows a primary bone tissue formed by structural fiber bundles as in other sauropod dinosaur osteoderms. Furthermore, on the basis of their gross morphology and microstructure, the bony structures originally classified as types 1 + 4 and 3 are more comparable respectively with dorsal and cervical ribs than any other kind of dermal or bony element. Due to poor preservation, the nature of the type 2 cannot be assessed but is here tentatively assigned to a pelvic girdle element. Although a phylogenetic reassessment of Agustinia is not the purpose of this paper, our paleohistological analyses have broader implications: by not supporting the dermal armor hypothesis for Agustinia, its inclusion in Lithostrotia is not justified in the absence of other diagnostic features.     

Testing the influence of gravity on flower symmetry in five <Emphasis Type="Italic">Saxifraga</Emphasis> species

Flower symmetry is considered a species-specific trait and is categorized in asymmetry, actinomorphic symmetry, bisymmetry and zygomorphic symmetry. Here we report on the intra-individual variation of flower symmetry in the genus Saxifraga and the influence of light, gravity and intrinsic factors on the development of flower symmetry. We tested five species—Saxifraga cuneifolia, Saxifraga imparilis, Saxifraga rotundifolia, Saxifraga stolonifera and Saxifraga umbrosa—concerning six flower parameters—angles between petals, petal length, petal pigmentation, angular position of carpels, movement of stamens and (only for S. imparilis and S. stolonifera) the length of the two lower elongated petals in regard to their position towards the stem. Specimens of all species were tested on a vertical clinostat as a gravity compensator, on a horizontal clinostat as a light incidence compensator and on a stationary control. The results show that the angle of incident light has no apparent impact on flower symmetry, whereas gravity affects the angular position of petals in S. cuneifolia and S. umbrosa and the petal colouration in S. rotundifolia. In S. cuneifolia and S. umbrosa, the absence of directional gravity resulted in the development of actinomorphic flowers, whereas the corresponding control flowers were zygomorphic. The development of flowers in S. rotundifolia was not altered by this treatment. The length of the two elongated petals in S. stolonifera and S. imparilis was not affected by gravity, but rather was determined by position of the flower within the inflorescence and resulted in asymmetrical flowers.     

Differential timing and latitudinal variation in sex ratio of Aquatic Warblers during the autumn migration

Differential migration has been extensively reported in spring, but less so in autumn, particularly in relation to sex in monomorphic bird species. Here, we analysed the autumn passage of a monomorphic, globally threatened passerine, the Aquatic Warbler Acrocephalus paludicola throughout Western Europe, with regard to age and sex. We showed that, overall, adults migrated earlier than first-year birds, and males migrated earlier than females during the autumn migration. This may be caused by an overall social dominance of adults over immatures, and differentiated migration strategy of males and females. In addition, we found male-skewed sex proportions, with a tendency to an equalised ratio in more southern stopover sites. This may indicate a male bias in the global population or different migration strategies of the sexes. Differential migration may cause the age and sex classes to be exposed differently to various threats affecting demographic structure of the species.     

Unusually high-pitched neonate distress calls of the open-habitat Mongolian gazelle (<Emphasis Type="Italic">Procapra gutturosa</Emphasis>) and their anatomical and hormonal predictors

In neonate ruminants, the acoustic structure of vocalizations may depend on sex, vocal anatomy, hormonal profiles and body mass and on environmental factors. In neonate wild-living Mongolian gazelles Procapra gutturosa, hand-captured during biomedical monitoring in the Daurian steppes at the Russian-Mongolian border, we spectrographically analysed distress calls and measured body mass of 22 individuals (6 males, 16 females). For 20 (5 male, 15 female) of these individuals, serum testosterone levels were also analysed. In addition, we measured relevant dimensions of the vocal apparatus (larynx, vocal folds, vocal tract) in one stillborn male Mongolian gazelle specimen. Neonate distress calls of either sex were high in maximum fundamental frequency (800–900 Hz), but the beginning and minimum fundamental frequencies were significantly lower in males than in females. Body mass was larger in males than in females. The levels of serum testosterone were marginally higher in males. No correlations were found between either body mass or serum testosterone values and any acoustic variable for males and females analysed together or separately. We discuss that the high-frequency calls of neonate Mongolian gazelles are more typical for closed-habitat neonate ruminants, whereas other open-habitat neonate ruminants (goitred gazelle Gazella subgutturosa, saiga antelope Saiga tatarica and reindeer Rangifer tarandus) produce low-frequency (<200 Hz) distress calls. Proximate cause for the high fundamental frequency of distress calls of neonate Mongolian gazelles is their very short, atypical vocal folds (4 mm) compared to the 7-mm vocal folds of neonate goitred gazelles, producing distress calls as low as 120 Hz.     

Three-year lifecycle,large body,and very high threshold temperature in the cricket <Emphasis Type="Italic">Gryllus argenteus</Emphasis> for special adaptation to desiccation cycle in Malawi

In temperate climates, the initiation and termination of diapause synchronize the stress-tolerant stage with the stressful season and reproduction with the non-stressful season in many insects. Synchronization is often regulated by photoperiodism.Voltinism and the ultimate size of adults are also important determinants for their lifecycle, and different diapause stages and voltinism patterns are known in crickets.Here, we investigated the life history of the African cricket Gryllus argenteus from Malawi, which is a typical arid tropical highland. The climate is characterized by alternating arid and wet seasons, each of which lasts for half a year, and where the available heat mass is much less than lowlands at the same latitude. We first measured the nymphal duration at each rearing temperature and calculated the lower developmental threshold (t ₀) to be 20.19 °C based on Ikemoto and Takai (2000) and 19.38 °C based on a conventional line-fitting method. These values are very high relative to many other insects. The local temperature in winter does not fall below 15 °C, but this is much higher than the lethal limit. This suggested that critical stress in this locality was not coldness but low precipitation in winter. We estimated, based both on local temperature change and the Ikemoto and Takai’s t ₀, that G. argenteus required 3 years to complete its lifecycle unlike wet lowland species, where univoltinism or multi-voltinism are commonplace. Photoperiodism was observed in this species, but due to a lag between annual cycles in photoperiod, temperature, and humidity, photoperiodism alone cannot atune their lifecycle with local conditions.Synchronization in this species was achieved by three different adaptations: photoperiodism, high t ₀, and large body size, which give it a long lifecycle. Although the species cannot achieve a univoltine lifecycle because of its high t₀ value, it can escape from dry season by entering diapause at moderate temperatures, probably thereby achieving adaptive synchrony of lifecycle with both favorable and unfavorable seasons. A comparison between a conventional photothermogram and a newly formulated photohydrogram or photohygrogram demonstrates that even though sufficient heat is available, scarcity of water and thus scarcity of foliage should force the cricket to maintain diapause at intermediate temperature. The results suggested that high t ₀, large body size, and multi-ennial lifecycle mutually affect each other and formulate a unique adaptation under such an extreme environment.