Raphidiopsis mediterranea Skuja represents non-heterocytous life-cycle stages of Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju in Lake Kastoria (Greece), its type locality: Evidence by morphological and phylogenetic analysis

The taxonomical relationship of Cylindrospermopsis raciborskii and Raphidiopsis mediterranea was studied by morphological and 16S rRNA gene diversity analyses of natural populations from Lake Kastoria, Greece. Samples were obtained during a bloom (23,830 trichomes mL⁻¹) in August 2003. A high diversity of apical cell, trichome, heterocyte and akinete morphology, trichome fragmentation and reproduction was observed. Trichomes were grouped into three dominant morphotypes: the typical and the non-heterocytous morphotype of C. raciborskii and the typical morphotype of R. mediterranea. A morphometric comparison of the dominant morphotypes showed significant differences in mean values of cell and trichome sizes despite the high overlap in the range of the respective size values. Additionally, two new morphotypes representing developmental stages of the species are described while a new mode of reproduction involving a structurally distinct reproductive cell is described for the first time in planktic Nostocales. A putative life-cycle, common for C. raciborskii and R. mediterranea is proposed revealing that trichome reproduction of R. mediterranea gives rise both to R. mediterranea and C. raciborskii non-heterocytous morphotypes. The phylogenetic analysis of partial 16S rRNA gene (ca. 920 bp) of the co-existing Cylindrospermopsis and Raphidiopsis morphotypes revealed only one phylotype which showed 99.54% similarity to R. mediterranea HB2 (China) and 99.19% similarity to C. raciborskii form 1 (Australia). We propose that all morphotypes comprised stages of the life cycle of C. raciborkii whereas R. mediterranea from Lake Kastoria (its type locality) represents non-heterocytous stages of Cylindrospermopsis complex life cycle.     

Raphidiopsis mediterranea Skuja represents non-heterocytous life-cycle stages of Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju in Lake Kastoria (Greece), its type locality: Evidence by morphological and phylogenetic analysis

The taxonomical relationship of Cylindrospermopsis raciborskii and Raphidiopsis mediterranea was studied by morphological and 16S rRNA gene diversity analyses of natural populations from Lake Kastoria, Greece. Samples were obtained during a bloom (23,830 trichomes mL⁻¹) in August 2003. A high diversity of apical cell, trichome, heterocyte and akinete morphology, trichome fragmentation and reproduction was observed. Trichomes were grouped into three dominant morphotypes: the typical and the non-heterocytous morphotype of C. raciborskii and the typical morphotype of R. mediterranea. A morphometric comparison of the dominant morphotypes showed significant differences in mean values of cell and trichome sizes despite the high overlap in the range of the respective size values. Additionally, two new morphotypes representing developmental stages of the species are described while a new mode of reproduction involving a structurally distinct reproductive cell is described for the first time in planktic Nostocales. A putative life-cycle, common for C. raciborskii and R. mediterranea is proposed revealing that trichome reproduction of R. mediterranea gives rise both to R. mediterranea and C. raciborskii non-heterocytous morphotypes. The phylogenetic analysis of partial 16S rRNA gene (ca. 920 bp) of the co-existing Cylindrospermopsis and Raphidiopsis morphotypes revealed only one phylotype which showed 99.54% similarity to R. mediterranea HB2 (China) and 99.19% similarity to C. raciborskii form 1 (Australia). We propose that all morphotypes comprised stages of the life cycle of C. raciborkii whereas R. mediterranea from Lake Kastoria (its type locality) represents non-heterocytous stages of Cylindrospermopsis complex life cycle.     

Tracking the Ovarian Cycle in Black-and-Gold Howlers (<Emphasis Type="Italic">Alouatta caraya</Emphasis>) by Measuring Fecal Steroids and Observing Vaginal Bleeding

A better understanding of a species’ reproductive physiology can help conservation programs to manage primates in the wild and develop assisted reproductive technologies in captivity. We investigated whether measurements of fecal progestin and estrogen metabolites obtained by a radioimmunoassay could be used to monitor the ovarian cycle of Alouatta caraya. We also compared the occurrence of vaginal bleeding with the hormone profiles. We collected fecal samples from 3 adult and 1 subadult captive female over 5 mo and performed vaginal cytology for the adults. The interval between fecal progestin surges in the adult females was 19.11 ± 2.14 d (n = 18 cycles). Fecal progestin concentrations remained at basal values for 9.83 ± 2.21 d (n = 18) and rose to elevated values for 9.47 ± 0.72 d (n = 19). The subadult female showed basal levels of fecal estrogen and progestin concentrations throughout the study, suggesting that our hormone measurements are valid to monitor the ovarian cycle. Bleeding periods coincided with basal levels of fecal estrogens and progestin at intervals of 19.8 ± 0.9 d and lasted for 4.1 ± 1.0 d. Although we obtained these data from only 3 individuals, the results indicate that this species likely has a menstrual-type ovarian cycle. These data provide the first endocrine profile for the Alouatta caraya ovarian cycle and are similar to results obtained for other howler species. This similarity is important for comparative studies of howlers, allowing for a better understanding of their reproductive physiology and contributing to a critical information base for managing Alouatta species.     

Influence of lipopolysaccharides and lipids A from some marine bacteria on spontaneous and Escherichia coli LPS-induced TNF-α release from peripheral human blood cells

Some endotoxic properties of lipopolysaccharides (LPS) and lipids A (LA) from the marine bacteria Marinomonas communis ATCC 27118^T, Marinomonas mediterranea ATCC 700492^T, and Chryseobacterium indoltheticum CIP 103168^T were studied. The preparations tested were shown to have high 50% lethal doses (4 μg per mouse for LPS from M. mediterranea and more than 12 μg per mouse for two other LPS and LA from C. indoltheticum) and were moderate (371 ± 37 pg/ml at 10 μg/ml of C. indoltheticum LPS), weak (148 ± 5 pg/ml at 1 μg/ml of M. mediterranea LPS), and zero (LA and LPS from M. communis and LA from C. indoltheticum) inducers of tumor necrosis factor α (TNF-α) release from peripheral human blood cells. The capacity of the LA and LPS samples from marine bacteria to inhibit TNF-α release induced by LPS from Escherichia coli O55: B5 (10 ng/ml) was also studied. Published in Russian in Biokhimiya, 2006, Vol. 71, No. 7, pp. 936–944.     

Temperature effect on the growth of <Emphasis Type="Italic">Buchnera</Emphasis> endosymbiont in <Emphasis Type="Italic">Aphis craccivora</Emphasis> (Hemiptera: Aphididae)

Effect of temperature on the growth of the primary endosymbiont Buchnera aphidicola in the cowpea aphid Aphis craccivora was studied by measuring quantitatively the copy number of 16S rDNA of this endosymbiont. A 1.5 kb segment of eubacterial 16S rDNA amplified by PCR from total DNA of Aphis craccivora was confirmed by RFLP analysis and sequence BLAST as that of Buchnera aphidicola. No secondary endosymbiont was detected in the aphid population studied. The relative levels of Buchnera ratio, quantified by real-time PCR, were higher in old nymphs than in young ones at temperatures between 10–30˚C, and this age-dependent difference was more pronounced at lower temperatures. Throughout the entire reproductive stage of Aphis craccivora, the relative levels of Buchnera ratio were higher at 10–25˚C than at 30˚C and 35˚C. A close relationship was found between these levels and the net reproductive rate (R ₀ ) of aphid, which was suppressed not only at 35˚C but also at 10˚C. The decoupling of Aphis craccivora and Buchnera response at low temperatures suggests that the cowpea aphid was more sensitive to low temperatures, while Buchnera was more sensitive to high temperatures.     

Reproductive and Life History Parameters of Wild Female <Emphasis Type="Italic">Macaca assamensis</Emphasis>

Information on basic reproductive parameters and life-history traits is crucial for the understanding of primate evolution, ecology, social behavior, and reproductive strategies. Here, we report 4 yr of data on reproductive and life-history traits for wild female Assamese macaques (Macaca assamensis) at Phu Khieo Wildlife Sanctuary, northeastern Thailand. During 2 consecutive reproductive seasons, we investigated reproductive behavior and sexual swelling size in 16 females and collected 1832 fecal samples. Using enzyme immunoassays, we measured fecal estrogen and progesterone metabolites to assess ovarian activity and timing of ovulation and to ascertain conceptions and pregnancies. Timing of reproduction was strictly seasonal (births: April–July, 86% in April–June, 4 yr, n = 29; conceptions: October–February, 65% in December–January, 2 yr, n = 17). Females showed no cyclic ovarian activity outside the mating season and conceived in their first or second cycle (mean: 1.2 cycles to conception, n = 13). Gestation length was on average 164.2 d (range: 158–170, n = 10), and females had their first infant at an age of 5 yr (n = 4). Interbirth intervals were bimodally distributed, with females giving birth on average every 13.9 or 23.2 mo. Shorter interbirth intervals were linked to early parturition within the birth season. Most females displayed subcaudal sexual swellings which, however, did not reliably indicate female reproductive status or fertility. Overall, our results fall within the range of findings reported for other macaque species. These results thus add to the growing body of information available for wild macaques, facilitating comparative studies for a better understanding of interspecific differences in social and reproductive patterns.     

Serum steroid hormone levels in relation to the reproductive cycle ofSebastes taczanowskii andS. schlegeli

Synopsis Changes in serum steroid hormones were studied during the reproductive cycle of two viviparous rockfishes of the genusSebastes. During the annual reproductive cycle of femaleS. taczanowskii, serum levels of estradiol-17β (E₂) gradually increased from their lowest in August to maximal levels towards the end of vitellogenesis in February, and rapidly returned to low levels in pregnant females in April and May. Serum progesterone (prog) fluctuated at low levels throughout the annual reproductive cycle, while 17α, 20β-dihydroxy-4-pregnen-3-one (17α, 20β-diOHprog) levels were high during gestation in May. Serum levels of these steroids were also measured in femaleS. schlegeli at weekly intervals during late vitellogenesis, gestation and post-parturition. In pregnant females, E₂ was high during vitellogenesis, then decreased and remained low throughout gestation. The 17α, 20β-diOHprog levels were low during vitellogenesis, then rapidly increased and remained high during gestation. On the other hand, prog values remained low, with temporal peaks coinciding with the peak of 17α, 20β-diOHprog during gestation. Based on these results and the literature, it is suggested that E₂ is the most important steroid involved in vitellogenesis and that 17α, 20β-diOHprog may play an important role in final oocyte maturation and subsequent gestation.     

Temperature-dependent development and reproductive traits of <Emphasis Type="Italic">Tetranychus macfarlanei</Emphasis> (Acari: Tetranychidae)

Development and reproductive traits of Tetranychus macfarlanei Baker & Pritchard (Acari: Tetranychidae) were investigated on kidney bean, Phaseolus vulgaris L., at eleven constant temperatures. Tetranychus macfarlanei was able to develop and complete its life cycle at temperatures ranging from 17.5 to 37.5°C. At 15 and 40°C, a few eggs (2–4%) hatched but further development was arrested. Development from egg to adult was slowest at 17.5°C and fastest at 35°C for both females and males. Using Ikemoto and Takai’s linear model, the estimated lower developmental thresholds for egg-to-female adult, egg-to-male adult and egg-to-egg development were 12.9–13.0°C. The thermal constants for the respective stages were 110.85, 115.99 and 125.32 degree-days (DD). The intrinsic optimum temperatures (T _Φ) calculated by non-linear SSI model were determined as 24.4, 24.4 and 24.2°C for egg-to-female adult, egg-to-male adult and egg-to-egg development, respectively. The net reproductive rate (R ₀) was highest at 25°C (167.4 females per female) and lowest at 17.5°C (42.6 females per female). The intrinsic rate of natural increase, r _m, increased linearly with the rising of temperature from 0.102 at 17.5°C to 0.441 day⁻¹ at 35°C. These values suggested that T. macfarlanei could be growing quickly in response to increasing temperatures from 17.5 to 35°C and provide a basis for predicting its potential geographical range.     

Reproductive cycle by histological characterization of the ovary in the butterfly goodeid Ameca splendens from the upper Río Ameca Basin, Mexico

The ovarian cycle was studied in Ameca splendens, a viviparous fish native to western Mexico. Two wild populations living in environments with differential conditions (a small pond adjacent to a reservoir and a spring) were examined to determine whether the conditions these populations are exposed to can elicit differences in the reproductive cycle. The two sites differ from each other with respect to several environmental factors: the spring has clear, oxygen‐rich water while the pond has higher levels of conductivity, hardness and inorganic nitrogen. Six stages of gonadal maturation were identified in A. splendens, based on histological and macroscopic characteristics of the gonad. The relative frequency of gonadic stages at both sites showed two reproductive peaks during the year: from March to May and from September to November. Histologically, ovaries exhibit an asynchronous development in both populations, revealing the existence of a multiple reproductive cycle. Relative mean condition shows organisms are in peak condition (K > 1) at age class 1+ as they recruit to reproduction; K was <1 following the onset of multiple reproduction. The Fulton condition factor shows that the mean condition is slightly higher in the spring population. The relative frequency of gonadal maturation differed between the study sites and is indicative of the plasticity of A. splendens in facing different conditions within the environments it inhabits.     

Seasonal changes in digestive enzyme (trypsin) activity of the copepods <Emphasis Type="Italic">Pseudocalanus minutus</Emphasis> (Calanoida) and <Emphasis Type="Italic">Oithona similis</Emphasis> (Cyclopoida) in the Arctic Kongsfjorden (Svalbard)

Seasonal activities of the digestive enzyme trypsin were measured between August 1998 and May 1999 to study different nutritional strategies of the two copepods Pseudocalanus minutus and Oithona similis in the Arctic Kongsfjorden (Svalbard) using a highly sensitive fluorescence technique. Stage-, depth- and season-specific characteristics of digestive activity were reflected in the trypsin activity. P. minutus females and stage V copepodids (C) had highest trypsin activities in spring during reproduction (197.5 and 145.7 nmol min⁻¹ ng C⁻¹, respectively). In summer stages CIII–V and in autumn stages CIV and V had high activities (80–116 nmol min⁻¹ ng C⁻¹) in the shallow layer (< 100 m) presumably as a consequence of prolonged feeding before descending to overwintering depth. Trypsin activities at depth (> 100 m) in summer and autumn were low in stages CIII and CIV (29–60 nmol min⁻¹ ng C⁻¹) and in winter in all stages in both layers (20–43 nmol min⁻¹ ng C⁻¹). Based on low trypsin activity, males most likely did not feed. In O. similis, the spring phytoplankton bloom did not significantly affect trypsin activity as compared to the other seasons. O. similis CV and females had high trypsin activities in summer in the deep stratum (304.5 nmol min⁻¹ ng C⁻¹), which was concomitant with reproductive processes and energy storage for overwintering. In autumn, stage CV and female O. similis had significantly higher activities than stage CIV (130–152 versus 78 nmol min⁻¹ ng C⁻¹), which is in accordance with still ongoing developmental and reproductive processes in CVs and females. Comparisons of both species revealed different depth-related responses emphasizing different nutritional preferences: the mainly herbivorous P. minutus is more actively feeding in the shallow layer, where primary production occurs, whereas the omnivorous O. similis is not as much restricted to a certain depth layer, when searching for food. P. minutus had lower levels of trypsin activity during all seasons. In contrast to P. minutus, higher enzyme activities in males of O. similis suggest that they continue to feed and survive after fertilization of females.     

Demographic characteristics of the copepod <Emphasis Type="Italic">Acanthocyclops americanus</Emphasis> (Sars, 1863) (Copepoda: Cyclopoida) fed mixed algal (<Emphasis Type="Italic">Scenedesmus acutus</Emphasis>)-rotifer (<Emphasis Type="Italic">Brachionus havanaensis</Emphasis>) diet

The predatory copepod Acanthocyclops americanus is commonly found in shallow ponds and lakes in Mexico. We tested the survivorship and reproduction-related variables of this copepod, isolated from Lake Huetzalin (Xochimilco, Mexico City), on four mixed diets comprising two algal concentrations (0.8 × 10⁶ and 1.6 × 10⁶ cells ml⁻¹ of Scenedesmus acutus) and two rotifer densities (1 and 8 ind. ml⁻¹ of Brachionus havanaensis). Survivorship patterns of naupliar and adult stages of A. americanus were evaluated at 24 ± 1°C. The demography experiments were initiated with five females and five males (1:1 ratio, 5th copepodites) into each of the 16 test [= 4 diet combinations × 4 replicates (cohorts)] jars containing 50 ml medium and with one of the chosen algal-rotifer diets. Data on the survival of naupliar and copepodites (up to V) showed a high death rate (80%) in A. americanus by the time nauplii reached the adult stage. The duration of developmental time for nauplii and the copepodite V (C-V) was about 28 days by which time A. americanus became adults. Food combination had a significant effect on both survival and duration of the naupliar and C-V but not on the development time in C-I, C-II, C-III, and C-IV. Naupliar stages showed highest life expectancy at low food levels (rotifers or alga). Adult male and female copepods showed better survival under higher availability of rotifers in the medium, while higher algal density resulted in steep mortality during the first days. Average adult lifespan and life expectancy of A. americanus varied from 19 to 23 days, depending on the diet combination. Age-specific reproductive output (m _x ) of female A. americanus showed low reproduction (<10 offspring per female on any given day) when raised on low rotifer density, regardless of the algal concentration. On the other hand, enhanced offspring production (average of about 50 nauplii per female) was recorded when the rotifer density was higher (i.e., 8 ind. ml⁻¹). Gross and net reproductive rates varied from 48 to 438 and 27 to 318 offspring per female, respectively. In general, higher availability of rotifers in the medium resulted in higher (8–10 times as compared to those in low rotifer density) gross and net reproductive rates. There was no significant difference in the generation time (13–14 days) in relation to the diet combination. The rate of population increase (r) (range: 0.29–0.69 per day) increased with greater abundance of B. havanaensis in the medium. Thus, our study showed that inclusion of animal protein in the diet is necessary for high population growth rates of A. americanus.     

Multinuclear stages of the life cycle ofAcetabularia mediterranea

Summary The reproductive stages of the life cycle ofAcetabularia mediterranea have been studied in Feulgen-stained material. Light-microscopical photographs of secondary nuclei, cyst formation, gamete formation, gamete release, zygote formation and early development of the germlings are presented. The time course of cytological events during gamete formation is described. Mitoses are found between 16 and 24 hours after the induction of cyst germination.The author is indebted to Mrs. S.Artelt who helped with the prepration of the specimens and the photographs.     

Response of the mink reproductive system to hormonal stimulation in october as a prognostic criterion of folluculogenesis and fertility

The responsess of the mink reproductive systems in October to a single intramuscular injection of chorionic gonadotropin (CG, Profasi R, Italy) at doses of 10, 20, 50, and 100 IU was studied. The estrous cycle state, folliculogenesis, and reproductive parameters of the female minks were estimated. To evaluate functional polymorphism in the reproductive system of the females in response to the CG injection, a dose of 20 IU was chosen. On the sixth day after administration of this dose of CG, the females (n = 185) were distributed according to the stages of the estrous cycle as follows: anestrus—71 animals (38.4%), anestrus-proestrus—37 (20.0%), proestrus—30 (16.2%), proestrus-estrus—14 (7.6%), estrus—33 (17.8%). In the females of the “anestrus-proestrus” and “proestrus” groups as compared with the other groups as well as with control, a statistically significantly higher fertility was revealed. The study of folliculogenesis in the females with different parameters of the estrous cycle in November demonstrated the high level of fertility to be due to ability of these females to produce, under influence of the CG injection, the maximal number of mature follicles. A high heritable responsiveness of the reproductive system of the females to the CG injection (coefficient of realized heritabilityh = 0.64; the calculation made on the data for the sisters) indicates that this method may be an additional criterion in the selection of females for fertility.     

Reproductive cycle and gonad development of the Northern Argentinean <Emphasis Type="Italic">Mesodesma mactroides</Emphasis> (Bivalvia: Mesodesmatidae)

The reproductive cycle and gonad development of the yellow clam Mesodesma mactroides was studied over a period of 24 months (January 2005–December 2006) at the Argentinean sandy beach Santa Teresita. Histological examination of gonadal tissue revealed that sex ratios did not significantly deviate from the proportion of 1:1 and no case of hermaphroditism was found. The reproductive cycle of M. mactroides followed an annual cyclicality, which was significantly correlated to monthly mean sea surface temperatures (SST). Oocytes showed highest abundance in winter, indicating a process of gonadal development and sexual maturation. The mean oocyte size decreased significantly during spring. Modal oocyte sizes decreased significantly during winter and late spring of each year, suggesting spawning events. The condition index was not useful in describing the annual reproductive cycle of M. mactroides. Ash-free, shell-free dry mass was chosen to detect the condition of the specimens, and this significantly correlated with monthly mean SST and the gametogenic cycle. Annual recruitment patterns during summer–autumn indicated a 3-month-long planktonic phase of M. mactroides. The reproduction cycle and gonad development of M. mactroides showed only weak differences between data from the present study and those collected 40 years ago.

[125I] gonadotropin binding to the ovary of an Indian major carp,Catla catla,at different stages of reproductive cycle

At different stages of the annual reproductive cycle ofCatla catla, a major Indian carp, specific binding of gonadotropic hormone to the plasma membrane receptors was demonstrated. Maximum specific binding of [¹²⁵I]Catla gonadotropic hormone was obtained at 30‡C and pH 7.5 during 2 h of incubation.Catla gonadotropic hormone binding was saturable with high affinity. Competitive inhibition experiment showed that binding site was specifically occupied by piscine gonadotropic hormone,Catla gonadotropic hormone and murrel gonadotropic hormone, human chorionic gonadotropin was a weak competitor while bovine thyroid stimulating hormone, bovine prolactin and ovine follicle stimulating hormone had no effect. Scatchard analysis ofCatla gonadotropic hormone binding to the plasma membrane preparation from the carp oocytes of different reproductive stages showed that the range of dissociation constant(K _d ) varied from 0.78 to 0.97 x 10^-10 M. However, maximum binding capacity (B-max) varied remarkably between the different stages of reproductive cycle, it was 6.11 ± 0.36 fmol/mg protein in the preparatory stage which increased to about three-fold in prespawning stage of reproductive cycle (17.0 ± 0.29 fmol/mg protein) and spawning (18.7 ± 0.17 fmol/mg protein) and lowest in postspawning stage of reproductive cycle (5.28 ± 0.28 fmol/mg protein). Fluctuation in the number of gonadotropic hormone binding site at different stages of annual reproductive cycle was found to be coincided well with the pattern of ovarian steroidogenesis in response toCatla gonadotropic hormone as determined by the formation of progesterone from pregnenolone.     

Behavioural and population responses to changing availability of <Emphasis Type="Italic">Artemia</Emphasis> prey by moulting black-necked grebes, <Emphasis Type="Italic">Podiceps nigricollis</Emphasis>

Chemical communication may inform about the location of prey, predators, co-specifics, and mate partners in zooplankton. In this study, we evaluated several life-history traits of the rotifer, Brachionus calyciflorus, exposed to conditioned media by a rotifer predator (Asplanchna brightwelli) and a cladocera competitor (Daphnia similis), quantifying population growth and life-table demography at two algal food levels (2.0 and 0.5 × 10⁶ cells ml⁻¹ of Chlorella pyrenoidosa). At both food levels, B. calyciflorus grown in predator-conditioned media had lower population abundance and slower population growth rate than controls. Conversely, the competitor-conditioned media treatments produced both higher rotifer population abundance and faster population growth rate than controls. Life-history parameters varied significantly depending on the presence of predator and competitor-conditioned media. The Asplanchna-conditioned media significantly decreased gross reproductive rate (GRR): 8–9 offsprings per female; net reproductive rate (R ₀): 6–7 offsprings per female; population growth rate (r): 0.34–0.37 day⁻¹; and increased generation time (T): 5.5–5.6 days. On the other hand, The Daphnia-conditioned media significantly increased the GRR (13–14 offsprings per female); net reproductive rate (8–9 offsprings per female); population growth rate (0.42–0.43 day⁻¹); and decreased generation time (4.9–5.0 days). However, the effects of food level on the life-history characteristic were not significant in both treatments. Maximum values of the population abundance and the population growth rate are significantly influenced by the predator densities and pre-culture time. This study suggests that rotifers use variable life-history strategies (low reproduction and high survivorship versus high reproduction and low survivorship) based on the presence of predators and competitors.     

Female reproductive behaviour,ovarian hormones and vaginal cytology of the induced ovulator, <Emphasis Type="Italic">Ctenomys talarum</Emphasis>

In the present study, we evaluated whether reproductive condition affects female reproductive behaviour in the induced ovulator Ctenomys talarum. We also explored the effect of the interaction with a male on the reproductive condition of females. To evaluate this, we arranged mating trials and evaluated female reproductive behaviour. Reproductive status of females was evaluated using a combined approach of vaginal smears, urinary progesterone and oestradiol, and ovarian histology. Behaviours denoting attraction (‘male sniff’ and ‘mount attempts’) and mutual courtship behaviours (‘spin’ and copula) were correlated with vaginal cytology before and oestradiol and progesterone levels in urine 12 h after male–female encounter. After 24 h of the interaction, oestradiol levels and vaginal epithelization increased while progesterone levels decreased in soliciting females. C. talarum females’ reproductive behaviour was related to its physiological reproductive state and vaginal cytology. The kind of male interaction, whether couples copulated or remained indifferent affected the later status of females. Females are induced ovulators by mating but male presence and interaction also affected other components of their reproductive physiology such as ovarian hormones and vaginal cytology.     

Relative growth and reproductive cycle in two populations of <Emphasis Type="Italic">Bolinus brandaris</Emphasis> (Gastropoda: Muricidae) from northern Tunisia (Bizerta Lagoon and small Gulf of Tunis)

A study on the relative growth and reproductive cycle of the purple dye murex (Bolinus brandaris) was performed from March 2007 to February 2008 in two populations with contrasting imposex levels (Carthage Byrsa — CB in the small Gulf of Tunis and Menzel Abderrahmane — MA in the Bizerta Lagoon). Both populations presented balanced sex ratios. Comparison of allometric relationships established between linear and ponderal variables (sexes confounded) revealed higher growth in CB than in MA. Mature individuals were found throughout the year, except for September in MA. Spawning periods occurred from March–April to May and from June to August in both sites. Spawning was associated to an increase in seawater temperature. Besides increasing the current knowledge on the biology of B. brandaris from the southern Mediterranean, the information gathered in the present study constitutes a useful baseline for the sustainable management of local wild stocks, namely by prohibiting collection of snails during the spawning season.