In search of a model system for exploring the Chemical Legacy Hypothesis:Drosophila melanogaster and geraniol

We required an experimental system in which to explore elements of the chemical legacy hypothesis, according to which molecules of environmental chemicals may persist on or in the body or immediate surroundings of larval or pupal insects and influence their habitat preferences in adulthood by affecting the maturation of the chemosensory pathways. Using a purpose-built apparatus which exploited the geotactic and phototactic behavior ofDrosophila melanogaster, we examined the pattern of responses to a range of dilutions of geraniol, a terpene of plant origin. Fruit flies avoided the geraniol at high concentrations. Although attraction at low doses and reduced aversion after larval, pupal, or early adult exposure to geraniol have been reported, we did not find either. Thus, we failed to generate the phenomenon described as "pre-imaginal conditioning" required for the model system. We discuss the results in relation to designing suitable assays for testing the Chemical Legacy Hypothesis.

Xylazine and a xylazine/fentanyl citrate/azaperone combination in farmed deer. I: dose rate comparison

Six 1-year-old farmed red deer were used to compare physiological and behavioural responses to a range of doses of 5% xylazine with or without the addition of 0.4 mg of fentanyl citrate and 3.2 mg of azaperone per ml. Each deer was randomly assigned to one of six treatments: xylazine alone at 0.4 and 0.6 mg/kg, the xylazinelfentanyl citrate/azaperone combination containing 0.2, 0.4 and 0.6 mg/kg of xylazine, or a sterile water control. Injections were given intramuscularly in the anterior neck, operator blind, on each of 6 sampling days between October and January, such that each deer received all treatments with 9-28 days between each treatment. Measurements included heart rate and respiration rate. A 0-3 scoring system (normal to nil response, respectively) was devised to record sedative responses (body stance, head position, degree of eye closure, palpebral reflex, resistance to movement of the head, response to noise) and analgesic responses to touch and pinching of the ear, and response to a needle prick in the gluteal region. Scores were added to produce a sedation score and analgesia score, respectively, for each treatment. Records were taken immediately prior to injection and thereafter at 5, 14, 25, 35, 60, 90, 120, 150, 180, 210, 240 and 300 minutes. All deer given each dose rate of the xylazine and the xylazine/fentanyl citrate/azaperone combination became recumbent. There was a tendency for the time to recumbency and variation of time to recumbency to be shorter at higher dose rates and with the addition of fentanyl citrate and azaperone to xylazine, particularly with xylazine at 0.4 mg/kg. These trends were not statistically significant (p>0.05). The duration of recumbency was shorter with the low dose of the xylazine/fentanyl trateiazaperone combination (0.2 mg/kg of xylazine) than for the higher doses of xylazine alone or the combination of drugs (p<0.05). There were no significant differences in heart rates or respiration rates between treatments, although all treatments significantly reduced both heart and respiration rates (p<0.01). The sedation scores showed similar peak responses and timing to peak responses (14-25 min) to both drug treatments and all dose rates, but the responses were less persistent for lower doses. The analgesia scores showed a similar pattern, with peak responses 14-35 minutes after administration and more persistence at higher dose rates of both xylazine alone and the xylazine/fentanyl citrate/azaperone combination. This study has shown that most physiological and behavioural responses to a range of doses of xylazine or the xylazine/fentanyl citrate/azaperone combination were statistically similar. However, there was a tendency for recumbency to occur more rapidly and with less variation in timing when the mid-range dose of the drug combination was used, supporting the observation by practitioners that the drug combination results in a more rapid and reliable state of recumbency at a lower dose rate of xylazine.

Suckling behaviour does not measure milk intake in horses, Equus caballus

Studies of parental investment in mammals have frequently used suckling behaviour to estimate energy transfer from mother to offspring, and consequently to measure maternal input. Such studies assume that the more an offspring sucks, the more milk it will receive. This assumption has been questioned, and a review of the literature found little support for it. To test if suckling behaviour provided an accurate index of milk or energy intake we used a radioactive isotope technique to label the milk of thoroughbred mares and to measure milk transfer to foals. We found no significant linear relationship between usual measures of suckling behaviour and milk or energy intake. No behaviours associated with suckling nor with characteristics of mares and foals improved the relationship; only the number of butts associated with each suck episode even approached significance. If we had used suckling behaviour to test theories on differential maternal investment our conclusions would have been in error. For example, female foals tended to suck for longer than males did but there was no difference in the amount of milk transferred. Consequently, we show that measures of suckling behaviour do not adequately predict milk intake in the domestic horse and we suggest that conclusions about differential maternal investment in mammals based on suckling behaviour are likely to be in error. Copyright 1999 The Association for the Study of Animal Behaviour.

Xylazine and a xylazine/fentanyl citrate/azaperone combination in farmed deer II: Velvet antler removal and reversal combinations

Three studies were undertaken on farmed red and red x wapiti deer to evaluate xylazine and a xylazine/fentanyl citrate/azaperone combination for velvet antler removal. In the first experiment, 30 1-2 year-old red and 25% red x wapiti deer whose velvet was to be removed were given either 5% xylazine alone at 0.5 mg/kg body weight intramuscularly or the same dose rate of a commercially available mixture of 5% xylazine with the addition of 0.4 mg of fentanyl citrate and 3.2 mg of azaperone per ml. Physiological, behavioural and analgesic responses and reversal times after yohimbine or yohimbine and naloxone were monitored. There were no differences in heart rate, respiration rate, sedative or analgesic properties detected between xylazine or the xylazine/fentanyl citrate/azaperone combination. All deer became recumbent, but those given the xylazine/fentanyl citrate/azaperone combination became recumbent more rapidly than those given xylazine alone (9.4 and 12.5 minutes, respectively, p<0.05). The arousal pattern and timing of reversal of xylazine and xylazine/fentanyl citrate/azaperone using yohimbine and yohimbine and naloxone, respectively, were similar. The second experiment evaluated the reversal of the xylazine/fentanyl citrate/azaperone combination with either yohimbine or yohimbine and naloxone in 43 3-year-old red deer stags after velvet antler removal. There were no differences in arousal pattern or time to standing between reversal treatments. Sixteen 1-year-old red and 25% red x wapiti stags were used in the third experiment to evaluate clinically the analgesic properties of xylazine and xylazine/fentanyl citrate/azaperone combination during velvet removal without the application of a local anaesthetic agent. Withdrawal responses were observed in most deer after the xylazine/fentanyl citrate/azaperone combination at dosages containing 0.5, 0.7 and 0.75 mg of xylazine/kg and after xylazine alone at 0.7 mg/kg, indicating that insufficient analgesia was provided by the systemic agent for the surgical procedure of velvet antler removal. These studies have shown that the knock-down effect of the xylazine/fentanyl citrate/azaperone combination was more rapid than that of xylazine alone, but that other physiological, behavioural and analgesic responses at doses used and evaluated by the methods used were similar. Reversal of both the xylazine and xylazine/fentanyl citrate/azaperone combination was similar when using either yohimbine alone for xylazine and the xylazine/fentanyl citrate/azaperone combination or yohimbine and naloxone for the xylazine/fentanyl citrate/azaperone combination. The evaluation of surgical analgesia for antler removal suggested that both xylazine alone and the xylazine/fentanyl citrate/azaperone combination provided insufficient analgesia and that local anaesthetic should be used in all cases.

Nonrandom mating in the two-spot ladybird (Adalia bipunctata): the influence of weight on mating success

In some populations of the two-spot ladybird, Adalia bipunctata, there is evidence that melanics of both sexes have a general mating advantage over the typical morph. There is also evidence that some female ladybirds possess a simple mating preference for melanic males. We have determined the influence of body weight on mating success in the two-spot ladybird and assessed whether weight differences might influence the mating success of the melanic morph. We found that the "formal mating tests" used in previous studies of the two-spot ladybird did not detect any influence of weight on mating success. Using more sensitive "singleton" tests, however, a significant mating advantage to heavier males was detected, irrespective of morph. There was also evidence in favor of a similar advantage to heavy females, but this was not present in all ladybird groups that were tested. Heavy individuals neither produced more eggs in matings nor showed higher activity rates. We suggest that some form of mate competition favors large individuals: for example, the larger an individual, the greater is the chance of an encounter with a potential mate. There is no evidence in this study that either sex chooses heavier mates. Effects of weight might contribute to the general melanic mating advantage found in some populations but cannot account for all the data in favor of a female mating preference for melanic males.

The status of the Spanish language in the United States at the beginning of the 21st century

"This study presents population projections for different linguistic components of the Spanish language group, that is, for English dominant bilinguals, Spanish dominant bilinguals and Spanish monolinguals [in the United States]. The population model combines parameters obtained from the U.S. Bureau of the Census for nonlinguistic characteristics with linguistic parameters estimated from the 1976 Survey of Income and Education. The number of persons speaking Spanish on a regular basis will climb to an estimated 16.6 million persons at the turn of the century. Further analysis reveals, however, that an additional 4.5 million persons will have left the group by ceasing to speak Spanish. In fact, in the absence of continued immigration, this language minority cannot maintain its current size and will undergo progressively more rapid decline over the course of time."

[Quebec's language policy and the behavior of young Quebecers of Greek and Portuguese origin]

"This paper briefly presents the results of surveys made in 1983 and 1984 within the Greek and Portuguese communities of Montreal [Canada], in order to investigate the reaction of these two groups with respect to policy measures directing their children towards the French school system. Results show that, among Greeks, legislation did not markedly affect the privileged place of English, while among Portuguese, who previously were already much more French-oriented, the main impact of these policy measures seems to have been a decline in the knowledge of English among the young." (SUMMARY IN ENG AND SPA)