The concentration of thiram in aqueous solution decreases by 50-75% within 20 min in the presence of cut pieces of apple, cucumber or celeriac with a section surface area of 160 cm2 each. The decomposition rate is predominantly influenced by the section surface area of the cut fruit and vegetable samples. Denaturing reaction conditions (exchange of the solvent water by methanol; boiling of sample material) will significantly slow down the decomposition rate. It was concluded that the thiram decomposition had been caused by enzymes on the section surface of the fruit and vegetable samples. For a specific determination of thiram, a simple rinsing of the intact fruit and vegetable material was appropriate as extraction method. For the screening of thiram residues, the often used Keppel method, which determines CS2 from thiram or dithiocarbamates seems to be applicable even if samples had been coarsely cut, since decomposition of the CS2-forming intermediates is slower than the breakdown of thiram itself. Therefore, specific determination of thiram is necessary only, if maximum residue limits for dithiocarbamates are not adhered to.

Infanticidal behavior of male common voles (Microtus arvalis) was investigated in relation to the age of unfamiliar pups. Sires from 18 pairs were removed after parturition of their offspring and replaced by unfamiliar males at different ages of the neonates. In group 1, containing six females with their offspring, the new male was introduced into the females' cages on day 1 after the parturition. In group 2 the new male was introduced on day 5 after parturition and in group 3 on day 9 after parturition. The male was removed after 3 days and the neonates recounted. Male common voles killed up to 100% of the neonates in litters containing neonates younger than 9 days by rapid bites to the head of the neonates (groups 1 and 2, mortality rates of 0.86 and 0.38). However, with older pups, a mortality rate of 0.06 was observed while 33% of the intruder males showed signs of injuries (group 3). These findings show that infanticidal behavior of male common voles represents one factor of pup mortality. The results are discussed in relation to changes in the degree of maternal aggression and in the context of the social system of the common vole for solving the conflict between postpartum estrous mating and infanticidal behavior of male common voles. Aggr. Behav. 23:293–298, 1997. © 1997 Wiley‐Liss, Inc.

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Seven matriarchal breeding groups of common voles (Microtus arvalis) were studied to test bonding between females when given the option to leave their family group, and the hypothesis that they explore more in areas with odours from related individuals compared to areas scented with odours from unrelated individuals.Young females were observed more frequently in the proximity of their mother and were recorded more often with their sisters than alone. Except for reproductive females, all females were seen more frequently in the initial home area than in areas of exploration. Females frequented an area scented with the odour of related females more often than one with the odour of unrelated, unfamiliar females, but only shortly before dark. In most test groups only the adult females reproduced although their daughters had reached the age of sexual maturity. The results indicate that young female M. arvalis tend to stay with their mother and may delay their own reproduction. When exploring the vicinity of the burrow young females tend to prefer areas with the scent from related females and can recognize odour cues after being separated from the odour donor for 3.5 weeks. This behaviour may minimize aggressive encounters, leading to dispersal toward related individuals.