No abstract

The degree of reduction in sex pheromone mediated responsiveness of male light-brown apple moth which is brought about by previous brief exposure to the pheromone is related to the concentration of that pre-exposure, and hence to the level of excitatory sensory input generated by it.We have shown previously (Bartell and Lawrence 1973) that the responsiveness of males of the lightbrown apple moth, Epiphyas postvittana (Walker), to female sex pheromone was reduced by previous exposure to it, even when there was a 5 h interval between the initial exposure to the pheromone and the subsequent bioassay test. In earlier experiments we investigated the effects of the duration of the preexposure and the interval between pre-exposure and bioassay, but did not investigate the effects of different concentrations of pheromone. A trial in which males received pre-exposure to different concentrations of pheromone is the subject of this note.All conditions regarding rearing and photoperiodic entrainment of the moths, ambient temperature and light intensity at the time of pre-exposure and of bioassay, the apparatus used and the experimental procedures employed were as reported in our earlier paper (Bartell and Lawrence op. cit.). Crude extracts of female abdomen tips were used as the pheromone source for both pre-exposures and subsequent bioassay, the quantity of sex pheromone present being expressed in female equivalents (F.E.).Pre-exposures were of 10 min duration and the interval between the end of this period and the start of bioassay was SO min, during which pheromone-free air was passed over the males. During pre-exposure

A combination of two sex pheromone compounds is required to elicit sexual response in males of Epiphyas postvittunu. Sequential exposure to the two compounds failed to elicit sexual response in males, but a pre-exposure sequence of alternated pulses of the two compounds did habituate males to the same extent as did pulsed pre-exposures to the compounds combined.

The use of NaOH can effectively reduce prion levels in an in vitro inactivation assay. After pretreatment of SBH with detergent, NaOH completely eliminates the PrPRES signal. Detergent may liberate lipid membrane-protected PrPSc to improve access to NaOH, which can then inactivate PrPSc by altering its structure. In cases of unidentified exposure to PrPSc during manufacturing, sanitizing procedures combining the use of detergent and NaOH may help to ensure minimal levels of contamination carryover in products.

Observations were made on the calling behaviour of virgin female Epiphyas postvittana, and on associated factors. The amount of calling varied with the age of the female, the longest total durations being on days 2 and 6 of adult life and the shortest on day 4. It is probable that the peak of activity occurs on day 2. The pattern o.f calling on day 6 was abnormal, probably as a result of the onset of senescence.Total pheromone content and the number of mature eggs in the ovary also varied with age. The pheromone content increased until day 5 and then dropped sharply --probably again due to senescence --and the number of mature eggs increased until days 3 and 4. The number on day 4 was not significantly different from that on day 3, but the high variance on day 4 indicated some females had oviposited. A 2-hour call by day-3 female~ caused a substantial drop in total pheromone content.