Summary 0 Phenology and reproduction were studied in three populations of the cleistogamous herb Oxalis acetosella during three growing seasons\ in order to see how the balance between chasmogamous "CH# and cleistogamous "CL# reproduction varies with tem! poral and spatial environmental variation and with plant size[ The numbers of CH and CL~ower buds\~owers\ immature capsules and mature capsules were counted per ramet\ ramet sizes were estimated\ and mature capsules were collected for seed counts[ 1 Both CH and CL~ower numbers were positively correlated with ramet size ex! pressed as leaf number\ but the correlation was much stronger in the CL phase[ CL ower production also varied signi_cantly between years and sites[ Thus\ CL product! ion in O[ acetosella was not independent of resources and climatic variation[ 2 When the e}ects of year and site were taken into account\ the probability of an individual~ower developing into a mature fruit was not higher in the CL phase than in the CH phase[ 3 CL production was a}ected by fertilization success in the CH phase[ Ramets with one or more CH~owers left unfertilized generally produced more CL buds than ramets with all their CH~owers fertilized[ The former group also tended to have more seeds per CL capsule[ 4 Since reproductive success in the two phases varies in di}erent temporal and spatial patterns\ cleistogamy in O[ acetosella is considered to be a bet!hedging strategy optimizing reproductive output in~uctuating environments[ 5 The _ndings of this study are in con~ict with the general view on cleistogamy as a fail!safe mechanism for back!up seed production\ una}ected by variations in resource supply and environmental conditions[ Keywords] chasmogamous\ reproductive rate\ resources\ spatial variation\ temporal variation Journal of Ecology "0887# 75\ 380Ð499

The aim of the present study was to identify relations between stereotyped behaviours (cribbing, weaving and box-walking) and wood-chewing in thoroughbred flat-racing horses (TB) and standardbred trotters and the different management, feeding and training factors to which these horses are exposed. This was obtained by inquiries to all the professional trainers of TB and trottinghorses used for racing in Sweden. The usable response rates were 61% for trotters and 72% for TB representing 4597 trotters from 234 stables and 644 TB from 38 stables. A small field study was carried out to control the validity of the main study which gave results similar to those in the main study. There was a large difference between the two horse categories in the occurrence of behavioural disturbances. The TB had significantly more stereotypies than the trotters (P < 0·001) but there were no differences in the occurrence of wood-chewing. There were several differences in external factors between the horse categories, e.g. trotters had more opportunities for social contacts with other horses, they also had more free time outside the stable and they were trained a shorter time per week than the TB. The TB were given larger amounts of concentrate than the trotters. Wood-chewing within each horse category was explained by the amount of roughage (P < 0·05 in trotters and P < 0·001 in TB) together with other factors. Stereotypies in the TB were explained by: amount of concentrate (positive relation), number of horses per trainer (positive relation) and amount of roughage (negative relation).

Three populations of the cleistogamous species Oxalis acetosella and one population of the cleistogamous species Viola hirta (during 2 years), were investigated to determine whether the fertilization success of chasmogamous flowers influences the number of per ramet produced chasmogamous seeds, cleistogamous flowers, cleistogamous seeds and the total number of released seed per ramet. In both species chasmogamous (CH) flowers are produced before the cleistogamous (CL) ones.Fertilization success influenced number of produced CH seeds per ramet. In both species, ramets with one or more unfertilized CH flowers produced significantly fewer CH seeds. The number of produced CL flowers per ramet varied due to site membership (0. acetosella) and ramet size, but also due to the fertilization success of CH flowers. In both species, ramets with some CH flowers left unfertilized, responded with an increased production of CL flowers and seeds. In none of the species did the fertilization success of CH flowers influence the total seed output per ramet. Consequently, the increased production of CL flowers compensatedjor any loss in fruit-and seed-set owing to unsuccessful fertilization of CH flowers.

Redbo, I., Ehrlemark, A. and Redbo-Torstensson, P. 2001. Behavioural responses to climatic demands of dairy heifers housed outdoors. Can. J. Anim. Sci. 81: 9-15. The aim of the present study was to investigate the behavioural responses to different climatic demands of growing dairy heifers, during winter at a latitude of 60°N. Two groups (n = 11, 12) of yearling dairy heifers were housed in two similar 3-ha enclosures, characterised by deciduous forest, ley and pasture. Each enclosure also contained a lying area, a heated water source and a feed bunk from which the heifers had free access to grass silage. The behaviour and location of each heifer were recorded by instant interval observations every 5 min between 0600 h and 2000 h during 23 observation days spread over the entire winter period. Outdoor temperature, wind speed and solar radiation were measured continuously. The climatic energy demand (CED, W m -2 ) was measured with a heated animal model. The climate had significant effects on all the main activities and on the location of the heifers. Higher CED values corresponded to a greater number of observations of heifers in the lying area, and a greater incidence of lying and of ruminating, but to a decreased incidence of eating and grazing. Increased migration to the forested areas instead of to open areas reflected increasing CED values. The results from the present study show that dairy heifers adapt their behavioural activity and choice of location to the climatic conditions, to reduce energy expenditure. Thus, dairy heifers can be sustained in a cold climate if they are provided with wind breaks and dry lying places.

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