Polygyny and Monoandry in the Ant Formica japonica (Hymenoptera: Formicidae)

Queen number, mating frequency and nest kin-structure of the ant Formica japonica were studied in the field and the laboratory. Nest excavation in the study site, the east slope of Mt. Fuji, Gotenba, Japan, revealed that F. japonica is weakly polygynous all year round and the queen number increases after the nuptial flight season, suggesting the adoption of newly mated queens by established nests. Dissection and laboratory rearing demonstrated that nearly all queens in polygynous nests had mated and were fertile with mature oocytes in their ovaries. Multilocus DNA fingerprinting was used to examine kin relationships among ants found in the same nests. The fingerprint band patterns were apparently governed by a simple genetic rule and suggested monoandry (single mating per queen). The mean band sharing score of DNA fingerprints among full sisters was 0.90, and the mean value between queens and their daughters was 0.75. Comparison of DNA fingerprints of adult and pupal workers with pupal gynes suggested that multiple queens in a nest may contribute unequally to gyne (new queen) production.     

Mating Behavior and Colony Founding of the Slave-Making Ant Formica sanguinea (Hymenoptera: Formicidae)

The mating and postmating behavior of reproductives belonging to two sympatric dulotic colonies of the facultative slave-making ant Formica sanguinea was analyzed in the field. Our observations showed that the European blood-red ant adopts a reproductive behavior similar to the male aggregation syndrome. Newly mated females return to a dulotic colony and often wait for a raid. Following a slave raid is an advantageous strategy to locate and invade host nests and to establish a new dulotic colony. In the laboratory, the following modes of colony founding were studied: independent, adoption, alliance, usurpation, and brood raiding. Independent foundation was possible only when several females were kept together. Alliance was obtained with females of two potential slave species (F. cunicularia, F. rufibarbis). Usurpation and adoption were more frequent in the incipient than in the mature host colonies. Mixed colonies were always obtained after the sack of the host pupae. It seems likely that, rather than conspecific adoption followed by budding, F. sanguinea relies on temporary parasitism to start new colonies.     

Functional, Metabolic, and Circulatory Changes Associated with Seizure Activity in the Postischemic Brain

Abstract: The present study was undertaken to explore how transient ischemia in rats alters cerebral metabolic capacity and how postischemic metabolism and blood flow are coupled during intense activation. After 6 h of recovery following transient forebrain ischemia 15 min in duration, bicuculline seizures were induced, and brains were frozen in situ after 0.5 or 5 min of seizure discharge. At these times, levels of labile tissue metabolites were measured, whereas the cerebral metabolic rate for oxygen (CMRO₂) and cerebral blood flow (CBF) were measured after 5 min of seizure activity. After 6 h of recovery, and before seizures, animals had a 40–50% reduction in CMRO₂, and CBF. However, because CMRO₂ rose threefold and CBF fivefold during seizures, CMRO₂ and CBF during seizures were similar in control and postischemic rats. Changes in labile metabolites due to the preceding ischemia encompassed an increased phosphocreatine/ creatine ratio, as well as raised glucose and glycogen concentrations. Seizures gave rise to minimal metabolic perturbation, essentially comprising reduced glucose and glycogen contents and raised lactate concentrations. It is concluded that although transient ischemia leads to metabolic depression and a fall in CBF, the metabolic capacity of the tissue is retained, and drug-induced seizures lead to a coupled rise in metabolic rate and blood flow.     

The Relationship between Canopy Cover and Colony Size of the Wood Ant Formica lugubris - Implications for the Thermal Effects on a Keystone Ant Species

Climate change may affect ecosystems and biodiversity through the impacts of rising temperature on species’ body size. In terms of physiology and genetics, the colony is the unit of selection for ants so colony size can be considered the body size of a colony. For polydomous ant species, a colony is spread across several nests. This study aims to clarify how climate change may influence an ecologically significant ant species group by investigating thermal effects on wood ant colony size. The strong link between canopy cover and the local temperatures of wood ant’s nesting location provides a feasible approach for our study. Our results showed that nests were larger in shadier areas where the thermal environment was colder and more stable compared to open areas. Colonies (sum of nests in a polydomous colony) also tended to be larger in shadier areas than in open areas. In addition to temperature, our results supported that food resource availability may be an additional factor mediating the relationship between canopy cover and nest size. The effects of canopy cover on total colony size may act at the nest level because of the positive relationship between total colony size and mean nest size, rather than at the colony level due to lack of link between canopy cover and number of nests per colony. Causal relationships between the environment and the life-history characteristics may suggest possible future impacts of climate change on these species.     

Octopaminergic system in the brain controls aggressive motivation in the ant, Formica japonica

The ant, Formica japonica, is polyphagous and workers hunt other insects as foods. In this study, interspecific aggression was examined in the workers and queens. Behavior experiments demonstrated that interspecific aggressiveness was significantly higher in workers than queens. Workers showed predatory aggressive behavior towards crickets, on the other hand, queens elicited threat behavior but they didn't attack crickets. In order to investigate neuronal mechanisms underlying regulation of aggressive motivation, the role of biogenic amine in the brain in evoking aggressive behavior was examined by measuring biogenic amine using high-performance liquid chromatography (HPLC) with electrochemical detection (ECD). No significant difference in the octopamine (OA) level was found between workers and queens, but the level of N-acetyloctopamine (NacOA) in the brain of queens was significantly higher than that of workers. This study suggests that OAergic system in the brain must involve in controlling aggressive motivation in the ants.     

Reversible and Irreversible Changes of Morphological Phase, Associated with Giant Colony Growth in Bacillus sp.

Newly-isolated strains of Bacillus sp. grew as discrete, smooth colonies, composed of short, flagellate, sporogenous rods. From these arose arborescent, rough variant colonies, composed of long, asporogenous, non-flagellate, septate bacilli (which were capable of continuous growth over several weeks to utilize the available surface and substrate); these variants did not revert. Some smooth colonies proceeded, after a qulescent period, to grow outwards in a pattern of radial filaments, but reverted to the original on subculture. The first process may be regarded as quasi neoplastic, or alternatively as the production of an advantageous variation; the second process is analogous with tissue differentiation. Both fulfil the same purpose of spreading growth, and confirm that the swarm colonies found in other bacteria are special examples of a general phenomenon.     

Effects of p,p''-DDT on the Rat Brain Concentrations of Biogenic Amine and Amino Acid Neurotransmitters and Their Association with p,p''-DDT-Induced Tremor and Hyperthermia

Male, Fischer strain 344 adult rats were given various doses (25-100 mg/kg) of p,p'-DDT by oral gavage, and levels of biogenic amines, their metabolites, and amino acid neurotransmitters, tremor activity, and rectal temperature were measured at several intervals (2, 5, 12, and 24 h) after dosing. Dose-related increases in rectal temperature and in tremor activity were observed at 50-100 mg/kg 12 h after dosing. Tremorigenic doses of DDT increased the 5-hydroxyindoleacetic acid (5-HIAA) level in hypothalamus, brainstem, and striatum, whereas doses of 75 and 100 mg/kg increased the 3-methoxy-4-hydroxyphenylglycol (MHPG) level in hypothalamus and brainstem and the 3,4-dihydroxyphenylacetic acid level in striatum. Six amino acids were assayed in the brainstem, hypothalamus, and striatum; aspartate and glutamate levels were increased only in brainstem at 25-100 mg/kg. No consistent changes in concentrations of taurine, glutamine, glycine, or gamma-aminobutyric acid were observed in any of the regions assayed. Time-related increases in rectal temperature were seen 2-12 h after dosing, and the presence of tremor was observed 5-12 h after dosing; for both the time of peak effect was at 12 h. The DDT-induced hyperthermia and tremor were associated with dose- and time-related increases in levels of 5-HIAA, MHPG, aspartate, and glutamate. It is suggested that an increase in the turnover rate of 5-hydroxytryptamine (5-HT) may be responsible for the DDT-induced hyperthermia, whereas increases in the metabolism of 5-HT and norepinephrine may be involved in the tremor.     

Nicotine-Induced Changes in Neurotransmitter Levels in Brain Areas Associated with Cognitive Function

Nicotine, one of the most widespread drugs of abuse, has long been shown to impact areas of the brain involved in addiction and reward. Recent research, however, has begun to explore the positive effects that nicotine may have on learning and memory. The mechanisms by which nicotine interacts with areas of cognitive function are relatively unknown. Therefore, this paper is part of an ongoing study to evaluate regional effects of nicotine enhancement of cognitive function. Nicotine-induced changes in the levels of three neurotransmitters, dopamine (DA), serotonin (5-HT), norepinepherine (NE), their metabolites, homovanillic acid (HVA), dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA), and their precursor, L-DOPA, were evaluated in the ventral and dorsal hippocampus (VH and DH), prefrontal and medial temporal cortex (PFC and MTC), and the ventral tegmental area (VTA) using in vivo microdialysis in awake, freely moving, male Sprague-Dawley rats. The animals were treated with acute nicotine (0.5 mg/kg, s.c.) halfway through the 300-min experimental period. The reuptake blockers, desipramine (100 microM) and fluoxetine (30 microM), were given to increase the levels of NE and 5-HT so that they could be detected. Overall, a nicotine-induced DA increase was found in some areas, and this increase was potentiated by desipramine and fluoxetine. The two DA metabolites, HVA and DOPAC, increased in all the areas throughout the experiments, both with and without the inhibitors, indicating a rapid metabolism of the released DA. The increase in these metabolites was greater than the increase in DA. 5-HT was increased in the DH, MTC, and VTA in the presence of fluoxetine; its metabolite, 5-HIAA, was increased in the presence and absence of fluoxetine. Except in the VTA, NE levels increased to a similar extent with desipramine and fluoxetine. Overall, nicotine appeared to increase the release and turnover of these three neurotransmitters, which was indicated by significant increases in their metabolites. Furthermore, DA, and especially HVA and DOPAC, increased for the 150 min following nicotine administration; 5-HT and NE changes were shorter in duration. As gas chromatography experiments showed that nicotine levels in the brain decreased by 75% after 150 min, this may indicate that DA is more susceptible to lower levels of nicotine than 5-HT or NE. In conclusion, acute nicotine administration caused alterations in the levels of DA, 5-HT, and NE, and in the metabolism of DA and 5-HT, in brain areas that are involved in cognitive processes.     

Developmental Changes in the NGF Content in the Brain of Young,Growing, Low-Birth-Weight Rats

The NGF content in each region of the brain of four-week-old rats was ranked in the decreasing order of cerebral cortex, hippocampus, cerebellum, midbrain/diencephalon, and pons/medulla ob-longata, and the NGF concentration, in the decreasing order of hippocampus, cerebral cortex, cerebellum, midbrain/diencephalon, and pons/medulla oblongata in both AFD and SFD groups. The NGF content and concentration in the cerebral cortex were about the same value at each age between those in the AFD and SFD groups. Those in the hippocampus were a little higher in the SFD group than in the AFD group at the ages of three and four weeks, unlike those in the other regions, where the values for the cerebellum, midbrain/diencephalon and pons/medulla oblongata tended to be somewhat higher in the AFD group than in the SFD group. The NGF concentrations in the hippocampus and cerebral cortex increased with growth: the concentration in the hippocampus at four weeks of age was about 4-fold of that at one week in the AFD group and about 5.7-fold of that at one week in the SFD group; and likewise the concentration in the cerebral cortex at four weeks of age was about 5.3-fold in the AFD group and about 7-fold in the SFD group. The NGF concentrations in the cerebellum decreased, and those in midbrain/diencephalon and pons/medulla oblongata hardly changed with growth in either AFD or SFD group. From these results NGF may have stronger implications for the neuronal growth in the hippocampus compared with those in the lower brain regions of the SFD rats.     

Metabolomics Reveals Dynamic Metabolic Changes Associated with Age in Early Childhood

Objectives

A detailed understanding of the metabolic processes governing rapid growth in early life is still lacking. The aim of this study was to investigate the age-related metabolic changes in healthy children throughout early childhood.

Methods

Healthy children from a birth cohort were enrolled in this study from birth through 4 years of age. Urinary metabolites were assessed at 6 months, and 1, 2, 3, and 4 yr of age by using ¹H-nuclear magnetic resonance (NMR) spectroscopy coupled with multivariate statistical analysis including principal components analysis (PCA) and partial least-squares discriminant analysis (PLS-DA). Metabolic pathway analysis was performed using the MetPA web tool.

Results

A total of 105 urine samples from 30 healthy children were collected and analyzed. Metabolites contributing to the discrimination between age groups were identified by using supervised PLS-DA (Q² = 0.60; R² = 0.66). A significantly higher urinary trimethylamine N-oxide (TMAO) and betaine level was found in children aged 6 months. Urinary glycine and glutamine levels declined significantly after 6 months of age and there was a concomitant compensatory increase in urinary creatine and creatinine. Metabolic pathway analysis using MetPA revealed similar nitrogen metabolism associated energy production across all ages assessed. Pathways associated with amino acid metabolism were significantly different between infants aged 6 months and 1 year, whereas pathways associated with carbohydrate metabolism were significantly different between children at ages 2 and 3 years.

Conclusions

Urine metabolomics ideally represents dynamic metabolic changes across age. Urinary metabolic profiles change significantly within the first year of life, which can potentially provide crucial information about infant nutrition and growth.     

Proximate Determinants of Reproductive Skew in Polygyne Colonies of the Ant Formica fusca

Understanding the determinants of reproductive skew (the partitioning of reproduction among co‐breeding individuals) is one of the major questions in social evolution. In ants, multiple‐queen nests are common and reproductive skew among queens has been shown to vary tremendously both within and between species. Proximate determinants of skew may be related to both queen and worker behaviour. Queens may attempt to change their reproductive share through dominance interactions, egg eating and by changing individual fecundity. Conversely, workers are in a position to regulate the reproductive output of queens when rearing the brood. This paper investigates queen behaviour at the onset of egg laying and the effect of queen fecundity and worker behaviour on brood development and reproductive shares of multiple queens in the ant Formica fusca. The study was conducted in two‐queen laboratory colonies where the queens produced only worker offspring. The results show that in this species reproductive apportionment among queens is not based on dominance behaviour and aggression, but rather on differences in queen fecundity. We also show that, although the queen fecundity at the onset of brood rearing is a good indicator of her final reproductive output, changes in brood composition occur during brood development. Our results highlight the importance of queen fecundity as a major determinant of her reproductive success. They furthermore suggest that in highly derived polygyne species, such as the Formica ants, direct interactions as a means for gaining reproductive dominance have lost their importance.     

Regulation by Delta-Sleep-Inducing Peptide of the Neurochemical Changes in the Brain Associated with Dopaminergic System Hyperactivity

The influence of a single injection of delta-sleep-inducing peptide (DSIP; 30 g/kg body weight) on neurochemical parameters of rats' brain was studied under the conditions of chronic administration of dopamine analogs inducing DA-system hyperactivity – 50 mg/kg body weight of L-DOPA for 30 days or 2,5 mg/kg body weight of amphetamine for 21 days. The parameters of serotonergic system (MAO A activity, 5-HT, and 5-HIAA contents) and of dopaminergic system (MAO B activity, DA, NA, and HVA contents) were investigated in the cortex and caudate nucleus of control, DA or amphetamine, and DSIP receiving rats. Changes caused by the two DA-system activating drugs had both similarities and differences, and the corrective action of DSIP also had certain peculiarities depending on the pharmacological preparation used for the induction of DA-system hyperactivity and on the investigated brain structure. It is supposed that DSIP action might be based on the activation of serotonergic system that ensures the adaptive behavior of the animals.     

Free Amino Acid, Protein and Water Content Changes Associated with Seed Development in Araucaria angustifolia

The free amino acid, protein, water and dry matter contents were determined during the seed development of Araucaria angustifolia. Soluble and insoluble proteins in the mature seed represent 4.2 % of the fresh matter. The embryonic axis stored the greatest amount of soluble proteins, while cotyledons both with the embryonic axis showed the largest quantities of insoluble proteins in the mature seed. The greatest concentration of free amino acids was detected during the stage when cotyledons start to develop. Glutamic acid, aspartic acid, alanine and serine were predominant in the whole seed while arginine, lysine and γ-aminobutyric acid were present in great amounts only in cotyledons and embryonic axis. Although megagametophyte was important as a source of free amino acids, it was not the major protein storage organ in the mature seed. In the embryogenetic process, the rise of cotyledons is closely related to physiological and biochemical changes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Colony sex ratios vary with queen number but not relatedness asymmetry in the ant Formica exsecta

Split-sex-ratio theory assumes that conflict over whether to produce predominately males or female reproductives (gynes) is won by the workers in haplodiploid insect societies and the outcome is determined by colony kin structure. Tests of the theory have the potential to provide support for kin-selection theory and evidence of social conflict. We use natural variation in kinship among polygynous (multiple-queen) colonies of the ant Formica exsecta to study the associations between sex ratios and the relatedness of workers to female versus male brood (relatedness asymmetry). The population showed split sex ratios with about 89% of the colonies producing only males, resulting in an extremely male-biased investment ratio in the population. We make two important points with our data. First, we show that queen number may affect sex ratio independently of relatedness asymmetry. Colonies producing only males had greater genetic effective queen number but did not have greater relatedness asymmetry from the perspective of the adult workers that rear the brood. This lack of a difference in relatedness asymmetry between colonies producing females and those producing only males was associated with a generally low relatedness between workers and brood. Second, studies that suggest support for the relatedness-asymmetry hypothesis based on indirect measures of relatedness asymmetry (e.g. queen number estimated from relatedness data taken from the brood only) should be considered with caution. We propose a new hypothesis that explains split sex ratios in polygynous social insects based on the value of producing replacement queens.     

Raiding and Foraging Behavior of the Blood-Red Ant,Formica sanguinea Latr. (Hymenoptera,Formicidae)

In this paper we report the results of a detailed study on the behavioral ecology of slave raiding and foraging activity in the European blood-red ant, Formica sanguinea Latr. The field study was conducted over an unbroken period of 78 days, during which the activity of two dulotic colonies of this facultative slave-maker was observed for 10 h each day. It was possible to observe 26 raids distributed over 23 days, among which 18 were followed by the sacking of nests belonging to the species F. cunicularia, F. fusca, and Lasius emarginatus, whereas 8 failed. Simple, continuous, and simultaneous raids occurred. We recorded the timing, frequency, distance, and direction of slave raids, including the number of participants and the type of booty. Particular attention was devoted to the scouting behavior and raiding organization. Moreover, every day, we observed foraging and predatory behavior, during which adult insects (mainly ants), seeds, and berries were retrieved to the dulotic colonies. On the basis of our observations F. sanguinea seems to be a very efficient slave-maker and predatory species of the Raptiformica subgenus. Moreover, its dulotic behavior may be regarded as a continuation and an expansion of its foraging and predatory behavior, as predicted by Darwin's hypothesis for the origin and evolution of slavery in ants.     

Changes in the Sugar Content of the Leaf Sheath of Dwarf Maize Seedlings Associated with Gibberellin-Induced Growth

Changes in the time in sugar and starch content of the firstleaf sheath were compared among normal, d₅, and GA₁-treated(1µg/plant) d₅ seedlings of Zea mays L., from which endospermshad been removed. The patterns of changes in the levels of thesecarbohydrates were more or less similar to one another amongthe three groups of seedlings. Generally, the levels decreasedtoward the time of maturation of the leaf sheath except forthe level of sucrose which showed a sharp increase followedby a decrease. There was an inverse relationship over time betweengrowth and levels of glucose and fructose. Although treatmentwith GA₁ resulted in a decrease in sucrose content, it had practicallyno significant effect on the levels of the other sugars. Inthe leaf sheath of d₅, growth is probably not limited by thelevels of these sugars, and GA-induced elongation does not seemto have any significant correlation with the changes in thelevels of sugars. ¹Present address: Department of Botany, Suri Vidyasagar College,Suri, Dt. Birbhum, West Bengal, India. (Received March 18, 1988; Accepted November 21, 1988)     

家兔自发性蛛网膜下腔出血早期脑损伤模型的初步研究

目的：建立一种可重复的、有典型神经损伤症状的自发性蛛网膜下腔出血（sAH）动物模型,为研究蛛网膜下腔出血后早期脑损伤（EBI）的机制提供可靠的动物模型。方法：选用新西兰大耳白兔60只,随机分为实验组、对照组、空白组。采用枕大池穿刺一次注入自体动脉血法建立SAH模型。在4h、8h、12h、24h、48h、72h时间点,观察比较行为学与脑组织形态学的变化。结果：（1）实验组枕大池和蛛网膜下腔内发现大量的血凝块和血液。（2）实验组光镜下可观察到蛛网膜下腔大量红细胞,神经元细胞水肿,电镜下可见胶质细胞空泡样改变,神经元细胞线粒体肿胀,髓鞘内存在空泡和板层分离现象。（3）实验组造模后均出现明显的神经系统损伤,对照组4h出现典型神经系统损伤表现,12h后恢复正常,空白组未见神经系统损伤表现。结论：枕大池一次注血法是一种简便、可重复的症状性自发性蛛网膜下腔出血早期脑损伤模型,适宜于研究早期脑损伤的致病机制。