INCREASED VIGILANCE TOWARD UNFAMILIAR HUMANS BY HARBOR (PHOCA VITULINA) AND GRAY (HALICHOERUS GRYPUS) SEALS

Two pairs of harbor ( Phoca vitulina ) and three pairs of gray ( Halicboeruls grypus ) seals were exposed to one of three human handlers for 15 min, twice a day, for a total of six sessions. Following habituation to the familiar handler, animals were then exposed to a novel human for 7 min, and then retested for 7 min with the familiar human. In all cases, animals responded to the unfamiliar human with increased vigilant behavior, i. e., they spent more time oriented towards the unfamiliar handler during the first 2 min of the test session than during the same interval of either the final habituation session or the retest with the familiar human ( P = 0.03 in all cases). There was also a tendency for seals to contact the familiar handler with their noses more rapidly than the novel human ( P = 0.06). These results support the hypothesis that phocid seals are capable of discriminating between individual humans in their environment, setting the stage for human-based Pavlovian conditioning.     

An adaptive benefit of facultative coprophagy in the German cockroach Blattella germanica

1. A possible adaptive benefit of coprophagy was investigated in nymphs of the German cockroach Blattella germanica (L.). 2. Newly ecdysed first instars, given no source of food other than conspecific faeces, survived significantly longer than first instars deprived of faeces. The faeces of adult males and females may be of different quality, however, because nymphs given female faeces were more likely to moult into the second stadium than nymphs given male faeces. 3. In contrast to first instars, second instars provided adult faeces survived only slightly longer than starved counterparts. Faecal feeding is therefore stage‐specific, as is the benefit derived from it. 4. The relationship between the nutrient composition of faeces and the survival of nymphs was also examined. First instars fed the faeces of adults that had been maintained on a high (50%) protein diet, died more slowly than first instars fed the faeces of adults that had been maintained on medium (22.5%) and low (5%) protein diets. Chemical analysis of faeces showed that the concentration of protein in adult faeces increased with the level of protein in the diet. Moreover, food choice assays showed that first instars, unlike adults, ingested more of the high‐protein diets. 5. These data support the idea that coprophagy is a stage‐specific adaptive behaviour that permits first instars to moult into the second stadium with minimal foraging.     

Degradation of mandelate and 4-hydroxymandelate by Rhizobium leguminosarum biovar trifolii TA1

Rhizobium leguminosarum biovar trifolii TA1 grows on 4-hydroxymandelate and enzymes involved in its catabolism are inducible. Strain TA1 does not grown on mandelate or cis, cis-muconate, but spontaneous mutants capable of growth on these substrates were isolated. Enzymes involved in mandelate degradation were also inducible. The presence of intermediates of the mandelate and hydroxymandelate pathways resulted in a significant decrease in some of the enzymes involved in their degradation. Succinate and acetate, end products of the pathways, and glucose caused reductions in the levels of enzymes in the mandelate and hydroxymandelate pathways.     

Seven polymorphic microsatellite DNA loci from the red‐spotted newt (Notophthalmus viridescens)

We describe polymerase chain reaction (PCR) primers and amplification conditions for seven microsatellite DNA loci isolated from the red‐spotted newt (Notophthalmus viridescens). Primers were tested on 16 individuals from two populations on the Savannah River Site in Aiken County, South Carolina. We detected six to 10 alleles per locus and an overall observed heterozygosity range of 0.31–0.81. Despite low heterozygosity at two of the seven loci, the high polymorphic information contents (from 0.54 to 0.85) of these markers render them useful for future studies of the behavioural and population ecology of this common salamander.     

Sequential changes in propionate metabolism during the development of cobalt/vitamin B12 deficiency in sheep

The changes in propionate metabolism that accompany cobalt deficiency in sheep are described. Two groups of sheep, fed either a cobalt sufficient or deficient diet, were given an iv propionate load at intervals during a 14 w experiment. There was a tendency towards increased propionate half-life as the animals became cobalt deficient. However, significant changes in the area under the plasma methylmalonic acid-time curve occurred very early, indicating significant impairment of propionate metabolism. Despite this, the area under the plasma glucose-time curve was unaffected by cobalt deficiency, suggesting that the impairment of propionate metabolism, although significant, is not extensive.