Roosting behavior and group stability of the big fruit-eating bat Artibeus lituratus (Chiroptera: Phyllostomidae)

The roosting behavior of the big fruit-eating bat, Artibeus lituratus (Phyllostomidae, Stenodermatinae) in an Andean region of Venezuela is described. Sixty-four video recordings made at three separate foliage roosts during 1 year showed that group size varied between two and 14 individuals. One male was regularly observed roosting with more females than others, and this male was associated with the highest quality roost, defined here as the highest, most structurally stable, and least disturbed. Males invariably occupied exclusive roosts during the study, whereas females frequently moved among adjacent roosts. The high roost fidelity of males appears to be related to the defense of the highest quality roosts. Because females were observed roosting with each of the three males present at the study site, female groups were considered unstable. We suggest that shuttling movements of individuals may reflect a commonly observed adaptation of foliage roosting bats related to the avoidance of predators and/or parasites. The type of male–female association observed in A. lituratus is consistent with a resource defense polygyny hypothesis.     

Relationship between male-male and male-female sexual behavior in 5-6-month-old male lambs

To characterize male–male sexual behavior during lamb development, to relate it with lamb body and testicular growth, and with sexual behavior toward estrual ewes, 40 Milchschaf male lambs, weaned at 45 days of age, were kept with ewes that were nursing younger lambs. Experimental lambs were weighed and scrotal circumference was measured every 2 weeks. Male–male sexual behavior was observed during 1–2 h every 2 weeks after birth until 7 months of age. Observations were recorded more intensively (3–4 h on five different days) for 2 weeks (5–6 months of age) as male–male sexual behavior increased during that period. Both mounting and mounted lambs were identified. An individual mounting index (MI) was calculated. To study male–female sexual behavior, lambs were individually located with two estrual ewes, and during 5 min the number of ano-genital sniffing, lateral approaches, mounts, and mounts with ejaculation were recorded. From those data, a libido index was also calculated. Male–male mounts (n = 308) were observed. Courtship behavior was displayed in 25% of interactions; mounts were accepted in 72.1% of attempted mounts. Mounts without previous courtship were accepted more frequently than mounts with previous courtship (P = 0.002). Lamb weight and scrotal circumference were not different according to MI groups. Lambs that mounted more times estrual ewes (first tertile) had greater (P = 0.04) MI (0.61 ± 0.10) than lambs with medium (0.27 ± 0.09) and less (0.30 ± 0.10) MI. The regression between MI and heterosexual libido index was r = 0.33 (P < 0.05). In summary, intensive male–male sexual activity during a short period of male lamb development was observed. There was a positive relationship between sexual behavior of male lambs towards other male lambs and towards estrual ewes.     

Effect of Moniliformis moniliformis density on distribution within the definitive host population (Rattus norvegicus)

The population dynamics of Moniliformis moniliformis was studied in ‘free-ranging’ laboratory rats, Rattus norvegicus, presented with different relative density levels of M. moniliformis in cockroaches, Periplaneta americana. Changes in selected population parameters of the negative binomial distribution were evaluated as indicators of changes in aggregation. A significant increase in the degree of aggregation of parasites occurred as a result of the increase in relative density of infective stages available to the rats. This increase in aggregation was due to the increase in over-dispersion that occurred in female rats only. The degree of aggregation in females was found to be significantly higher than that in males at both treatment levels. The best indicators of the degree of aggregation were found to be the ratio of the variance to the relative density and the ratio of the log-variance to log-relative density. Changes in k were not correlated with changes in over-dispersion or the relative density.     

Dispersal pattern of the sand fly Lutzomyia neivai (Diptera: Psychodidae) in a cutaneous leishmaniasis endemic rural area in Southeastern Brazil

The dispersal pattern of the sand fly Lutzomyia neivai was studied through mark-release-recapture experiments in an American cutaneous leishmaniasis endemic rural area in Southeastern Brazil. Over 6500 specimens were marked with fluorescent powder and released in forest edge and peridomicile habitats from August to November 1999, February and April 2000. Recapture attempts were made using Shannon and CDC traps up to eight successive nights after releases. A total of 493 (7.58%) specimens were recaptured. The number of recaptured males and females of L. neivai in CDC traps was not affected by the distance between the trap and the release points. Approximately 90% of males and females recaptured in CDC traps were caught up to 70 m from the release points. The maximum female flight range recorded was 128 m. The average flight range per day was less than 60 m for males and females. Of the flies released in forest edge, approximately 16% of the recaptured females were caught in Shannon traps in the peridomicile habitat. The results indicate that the movements of L. neivai are spatially focal and the possibility of dispersion from forest to peridomicile habitat may be an important way of contracting leishmaniasis in dwellings.     

Pollen recognition and rejection during the sporophytic self-incompatibility response: Brassica and beyond

Many hermaphrodite flowering plants avoid self-fertilization through genetic systems of self-incompatibility (SI). SI allows a plant to recognize and to reject self or self-related pollen, thereby preserving its ovules for outcrossing. Genes situated at the S-locus encode the ‘male’ (pollen) and ‘female’ (pistil) recognition determinants of SI. In sporophytic SI (SSI) the male determinant is expressed in the diploid anther, therefore haploid pollen grains behave with a diploid S phenotype. In Brassica, the male and the female determinants of SSI have been identified as a peptide ligand and its cognate receptor, respectively, and recent studies have identified downstream signalling molecules involved in pollen rejection. It now needs to be established whether the Brassica mechanism is universal in species with SSI, or unique to the Brassicaceae.     

An experimental investigation of patch use by female monarch butterflies,Danaus plexippus (L.)

Monarch butterflies, which breed throughout the year in southeastern Queensland, Australia, were studied in four dense milkweed patches during the winter months (June-August) 1983. The percentage of marked females recaptured was measured in each of four 15-day sampling periods. In patches where males were experimentally removed, female recapture rate decreased compared with patches which had the same density reduction but no change in sex ratio. There was a significant correlation between female recapture rate and the proportion of males in samples, but female recapture rate was not correlated with population density, the number of males, the number of females or the proportion of young butterflies in the samples. We propose that females assessed patch quality by the sex ratios, and left a patch sooner if encounter rate with males was low. Since males provide a nutrient ‘reward’ during copulation, they may be a limited resource for females during winter. An alternative interpretation, that females left a patch sooner when female density was higher, was not supported as strongly by the data.     

A new species of Liropus (Crustacea, Amphipoda, Caprellidae) from Le Danois bank (southern Bay of Biscay)

A new species of the genus Liropus (Crustacea, Amphipoda, Caprellidae) is described based on specimens collected from Le Danois bank (‘El Cachucho’ fishing grounds), Bay of Biscay. Liropus cachuchoensis n. sp. can be distinguished from all its congeners mainly by the absence of eyes and by the presence of a dorsal projection proximally on pereonites 3, 4 and 5 in males, on 3 and 5 in females. The new species has been found living on muddy bottoms on the southern flank of the bank and adjacent continental slope, between 619 and 1062 m depth, with a maximum abundance (56.1 ind./100 m²) recorded at 1044–1062 m. Morphological comparisons among the world's members of Liropus, a key to species, and data on their distribution are presented.     

Homosexual male pairing in Schistosoma mansoni

and 1988. Homosexual male pairing in Schistosoma mansoni.International Journal for Parasitology 18: 1115–1117. To see whether male worms within the gynecophoral canal of another male worm would become feminized (i.e. express vestigial female-associated genes), we established homosexual pairs by twice exposing mice to male cercariae with a 4 or 6-week interval, and perfusing 3–5 weeks later. From 13 to 34% of these worms were found in pairs, compared with 0 to 7% in singly exposed controls. ‘Inner’ males in homosexual pairs showed no histological evidence of female reproductive structures, but were stunted, had poorly developed testes, and the high nuclear density characteristic of mature females. More vitelline follicles occurred in unpaired unisexual males than in homosexually paired males, fewest in bisexually paired males. Uptake of tyrosine, an indicator of vitelline development, occurred in the same relative order. The gynecophoral microenvironment often led to stunting, probably through starvation induced by the relative inaccessibility of host blood to homosexually clasped males.     

Functional expression of cDNAs for bovine 11 beta-hydroxylase-aldosterone synthases, P450(11 beta)-2 and -3 and their chimeras.

Two molecular species of bovine P450(11β), P450(11β)-2 and P450(11β)-3 have been identified, in which the amino acid differences were found at the 6th, 36th and 82nd positions from the NH₂-termini of the mature proteins. They catalyzed the 11β-, 18- and 19-hydroxylation and aldosterone formation from 11-deoxycorticosterone, and the rate of production of 18-hydroxycorticosterone and aldosterone by P450(11β)-3 was greater than that by P450(11β)-2 [Morohashi et al., J. Biochem. 107 (1990) 635–640].

In this study, chimeric clones were constructed whose 6th, 36th and 82nd amino acid residues were exchanged with each other. Two original clones and six chimeric clones were expressed in COS-7 cells, and their steroidogenic activities studied. The ratio of aldosterone or 18-hydroxycorticosterone production to corticosterone production by one clone was compared with that of the other. The ratios for the four clones having Gly36 [P450(11β)-3 type] were 0.08–0.22, whereas those for the clones having Ser36 [P450(11β)-2 type] were 0.03–0.05, suggesting that the Gly36 structure is important for aldosterone production.     

Use of gas chromatograms of essential leaf oils to compare eight taxa of genus Angophora (Myrtaceae): possible relationships to the genus Eucalyptus

Essential oils were extracted from leaves of eight taxa of the genus Angophora, and then analysed. As expected the individual components of these oils were essentially the same as those found in the Eucalyptus species of our earlier studies (Bignell et al., 1997b. Flavour Fragrance J. 12, 423-432). In addition, as is also the case with the bloodwood eucalypts, only relatively low yields of oil were obtained. In all cases the Cineole component was extremely small, but the oils of six of the eight contained very large concentrations of the sesquiterpene Bicyclogermacrene. A table of the 52 major oil components is included. Principal components analysis (PCA) was performed on the gas chromatograms (GC) of the essential oils and the resulting scores plots compared with the cladistic classification of Thiele and Ladiges (1988). Cladistics 4, 23–42). Because of the close relationship between genus Angophora and Eucalyptus ‘subgenus’ Corymbia, the GC data for the eight Angophora taxa were combined with corresponding data for eleven randomly chosen taxa from ‘subgenus’ Corymbia (Bignell et al., 1996b, Flavour Fragrance J. 11, 339–347; 1997a, Flavour Fragnance J. 12, 277–284) and a PCA performed on the total system.     

Anisotropy of photosynthetic membranes and the degree of fluorescence polarization

The degree of fluoresence polarization, P, of unoriented and magnetically oriented spinach chloroplasts as a function of excitation (400–680 nm) and emission wavelengths (675–750 nm) is reported. For unoriented chloroplasts P can be divided into two contributions, P_IN and P_AN. The latter arises from the optical anisotropy of the membranes which is due to the orientation with respect to the membrane plane of pigment molecules in vivo. The intrinsic polarization P_IN, which reflects the energy transfer between different pigment molecules and their degree of mutual orientation, can be measured unambiguously only if (1) oriented membranes are used and the fluorescence is viewed along a direction normal to the membrane planes, and (2) the excitation is confined to the Q_y (≈ 660−680 nm) absorption band of chlorophyll in vivo. With 670–680 nm excitation, values of P using unoriented chloroplasts can be as high as +14%, mostly reflecting the orientational anisotropy of the pigments. Using oriented chloroplasts, P_IN is shown to be +5±1%. The excitation wavelength dependence studies of P_IN indicate that the carotenoid and chlorophyll Q_y transition moments tend to be partially oriented with respect to each other on a local level (within a given photosynthetic unit or its immediate neighbors).     

Dispersal of phlebotomine sand flies (Diptera: Psychodidae) in a Colombian focus of Leishmania (Viannia) braziliensis.

Dispersal of five species of phlebotomine sand flies was studied in a coffee plantation near Arboledas, Colombia, by mark-release-recapture studies using fluorescent powders. The estimated recapture rate for males of Lutzomyia shannoni marked and released during the day was 28.1%, significantly higher than that for all other species (p < 0.05). Recapture rate of female Lu. shannoni was 9.5%, and no females of the other four species were recovered. This suggests either that Lu. shannoni is a more sedentary species than the others, or that the large trees on which these insects were captured and recaptured function as foci of lekking behaviour in males. The high recapture rates of females of this species may indicate that oviposition occurs in close proximity to the bases of these trees. Although most marked sand flies were recaptured within 200 m of their release point, a single female Lu. gomezi was recovered 960 m away 36 h after release. This suggests that the dispersal capacity of Lutzomyia species may be greater than has been thought, an important consideration in future control programs directed against these insects in Leishmania-endemic areas.     

Lipoprotein-associated paf (LA-paf) was found in washed human platelets and monocyte/macrophage-like U937 cells

Beyond cholesterol, inflammatory ether phospholipids such as platelet-activating factor (paf) may play a role in atherogenesis. (1) We detected a paf-like compound (‘LA-paf’) associated with human serum lipoproteins, mainly in LDL but not with the lipoprotein-poor fraction. (2) LA-paf was also found in washed human platelets, from where it was partially released during platelet aggregation in response to paf (50 nM) or thrombin (1 U). In addition, resident monocyte/macrophage-like U937 cells carried huge amounts of LA-paf (41 ng per 10⁷ cells) and metabolized added [³H]paf to a labelled compound co-eluting with the retention time of LA-paf in standard HPLC. (3) Functionally, LA-paf had a comparable potency to synthetic paf, because LA-paf aggregated washed aspirin-treated platelets in a concentration-dependent manner. The specific paf receptor antagonist WEB2086 inhibited the platelet aggregation induced by three distinct LA-paf preparations as compared with synthetic paf with similar inhibitory concentrations (IC₅₀: 35.6 ± 12.8, 24.0 ± 4.0, 38.0 ± 15.8 nM for LA-paf, and 43.6 ± 6.5 nM for synthetic paf), indicating that LA-paf interacted with paf receptors. (4) However, LA-paf had a distinct retention time using high-pressure liquid chromatography (HPLC) as compared with synthetic paf. LA-paf eluted at 9–15 min and synthetic paf at 21–24 min. In addition, total and non-specific [³H]paf binding to intact washed human platelets was affected differently by the two unlabelled agonists: while LA-paf increased total and non-specific (but not specific) binding in a significant manner (P < 0.002 and P < 0.007) as LDL did (P < 0.006 and P < 0.03), synthetic paf decreased total binding (P < 0.03). Similarly, low-density lipoproteins (LDL) increased significantly the total [³H]paf binding. In contrast, paf did not affect specific [¹²⁵I]LDL binding to human fibroblasts. Our results show the presence of LA-paf in lipoproteins,     

Parity of female goats does not influence their estrous and ovulatory responses to the male effect

The objective of the present study was to determine whether parity is a factor that influences the estrous and ovulatory responses of female goats when they are stimulated by males that show increased sexual activity. To stimulate sexual activity, four adult male goats were subjected to photoperiodic treatment for 2.5 months comprising long days, with the treatment commencing on 1 November. On 14 April at 1900 h, a group of multiparous females (n = 21) and a group of 16 months-old nulliparous females (n = 19) were exposed to four bucks (two per group) for 15 days. Throughout the study period, the estrous behavior of these female goats was detected twice on a daily basis. Ovulations of the female goats were determined by ecography on days 7 and 18 after exposure to males. The sexual behavior of males was recorded twice every day from 0800 to 0900 h and from 1730 to 1830 h during the first 4 days after introduction in the pen of females. The total cumulative proportion of multiparous females that had ovulations (100%) and displayed estrous behavior (100%) during the 15 days of exposure to males did not differ (P > 0.05) from that of nulliparous females (100% and 95%, respectively). The interval between introduction of males and onset of estrous behavior did not differ (P > 0.05) between multiparous (1.9 ± 0.1 days) and nulliparous (1.7 ± 0.2 days) females. The proportion of females displaying a short estrous cycle was greater (P < 0.05) in multiparous (13/21, 62%) than in nulliparous (5/19, 26%) females. Duration of these shorter than typical estrous cycles did not differ (P > 0.05) between groups (multiparous: 5.2 ± 0.3 days, nulliparous: 4.5 ± 0.1 days). The number of anogenital sniffings was greater (P < 0.001) in males exposed to nulliparous than in those exposed to multiparous females. In contrast, the number of mounting attempts was greater (P < 0.01) in males that were introduced to multiparous than in those that were introduced to nulliparous does. The number of flehmen, nudging, self-marking with urine, and mounts was not different (P > 0.05) between males that were in contact with multiparous and nulliparous females. These results indicate that regardless of parity, female goats respond to male introduction if they are stimulated by males that were previously exposed to artificial long days to increase their sexual behavior.     

Male sterility and restored fertility in annual mercuries, relations with sex differentiation

The paper summarizes the researches conducted on male sterility in Mercurialis annua. Totally sterile individuals are very scarce in the dioecious species showing as the other Mercuries, unisexual flowers devoid of rudiments of the opposite sex. From one sterile male mutant, a ‘sterile series’ was conducted and genetics was studied. Sterile, semisterile, restored fertile male lines were constructed as well as female lines containing the inducer gene of male sterility, both fertility restorers and the sensitive cytoplasm. Morphology and ontogeny of these isogenic lines were presented. Male sterile anthers (empty) present a splitted tapetum and an abnormal meiotic end. Restored fertile male lines were normal. The relative abundance of auxin and cytokinins was studied. A specific cytokinin pathway measured as a background in fertile lines, the cis-oxidized pathway characterised the ‘sterile series’. Restoration of normal meiosis and tapetum appeared for the highest quantities of cis-zeatin (669 ng instead of 192 ng/100 g fresh weight in totally sterile). Auxin quantities were abundant compared with the normal males. Gene expression in the ‘sterile series’ was also compared with the fertile lines. t-RNAs specific for normal females were expressed in the male ‘sterile series’. Hybridization kinetics and in vitro translations pf poly(A)⁺RNAs demonstrate specific sequences for each line. Comparisons between identical organs (normal fertile male/restored fertile male or normal female/female of the ‘sterile series’) exhibited nearly 10% differences. The results suggest that for stamen development, a cascade of regulators probably exists: sex genes acting on the induction of stamen or pistil, then genes for sterility/restoration of fertility acting in anthers. Fertility-sterility regulators control the synthesis of a specific cytokinin pathway. The new hormonal signals are linked to several specific genes expressed in the floral morphology characterizing each line of the ‘sterile series’.     

Schistosoma mansoni and Schistosoma japonicum: Utilization of amino acids

, , and 1972. Schistosoma mansoni and Schistosoma japonicum: utilization of amino acids. International Journal for Parasitology 2: 425–430. The production of ¹⁴CO₂ from 12 labeled amino acids by S. mansoni and S. japonicum was studied. No ¹⁴CO₂ was detected from incubations with glycine, isoleucine, leucine, lysine or phenylalanine. Differences were found between sexes and/or species for the other amino acids studied. Species related differences included a greater rate of metabolism of glutamic and aspartic acid by S. mansoni than by S. japonicum. Proline and histidine were utilized by S. mansoni males and females, respectively. S. japonicum male worms did not utilize proline, while histidine was not utilized by the female of this species. Major sex related differences included greater ¹⁴CO₂ production from glutamic acid, aspartic acid and arginine by S. mansoni males than by females, and the utilization of histidine by male S. japonicum but not by females. Incubation in tyrosine resulted in the release of only small amounts of ¹⁴CO₂ by female worms of both species but no ¹⁴CO₂ production by male worms.     

Sex ratio in catches of American mink – How to catch the females

To protect seabirds breeding on small nearshore islands (“sites”) along the coast of west Scotland from American mink, continuous year-round conventional cage trapping was carried out at constant effort at ten sites for three years (2003–2005) and at five of these sites for 10 years (1997–2006). In both periods, trapped male mink outnumbered females for most of the year, usually by more than two to one, with peaks of males in April–May and in September–October. However, a striking change took place in August–September, when the sex ratio of catches became close to unity. Most of the trapped females were caught in these two months. The chance of catching a female by this method was seven or eight times greater in August–September than during the rest of the year. Relatively few mink of either sex were caught in November–February. These findings, particularly the greatly increased catch of females in August–September, may be useful to others working to control alien American mink.     

Movement of the grape berry moth, Endopiza viteana: displacement distance and direction

Abstract. Mark–release–recapture is used to quantify displacement by adults of the North American grape berry moth, Endopiza viteana Clemens (Lepidoptera: Tortricidae) under field conditions. Moths marked with fluorescent dust are released eight times in the centre of a vineyard over 2 years, and recaptured using pheromone traps and interception traps. In vineyards, male moths are recaptured an average of 13.8 ± 0.8 m from the release site (maximum 58.2 m), whereas female displacement is similar with average flight distances of 11.4 ± 6.7 m (maximum 41.2 m). Increasing wind speed during moth flight activity periods suppresses displacement by both sexes, and females are less likely than males to fly in winds above 0.6 m s^?1. The majority of males are recaptured upwind from the release site or at a tangent to the overall mean wind direction when responding to pheromone traps, whereas female moths trapped in interception traps exhibit a large variability in direction from the release point. Releases of marked moths in woods adjacent to a vineyard demonstrates interhabitat movement by E. viteana males and by a single female. The average maximum displacement by males during interhabitat movement is 105.4 ± 3.9 m, significantly greater than the average maximum of 39.7 ± 6.7 m inside the vineyard habitat.     

Joint effect of nitrogen and phosphorous on glucose oxidase production by Aspergillus niger: Discussion of an experimental design with a risk of co-linearity

The combined effects of nitrogen and phosphorous on the production of glucose oxidase and gluconic acid by Aspergillus niger cannot be adequately described with Monod-type model, neither do they fit well to linear equations with interactions N × P, nor quadratic with N² and P² terms. On the other hand, the interactions of type N²P and NP², although common in real cases such as enzymatic kinetics in the presence of inhibitors, should be verified – if included in empiric models – by means of designs that can lead to artefactual results derived from the co-linearity. To avoid this risk we propose a procedure, based on the ‘bootstrap’ algorithm, which provided consistent results in the mentioned bioproductions. Applied together with methods of response surface and gradient, said procedure allowed to optimize the enzyme production as a function of the concentrations of N and P, to quintuple the initially obtained levels, and to explain other culture behaviours related with the sources of these nutrients.