Effects of elevated temperature on multi-species interactions: the case ofPedunculate Oak, Winter Moth and Tits

1. The effects of temperature on the Oak-Winter Moth-Tit food chain were st udied at Wytham Wood, Oxford, and experimentally in the controlled environm ent solardomes at the institute of Terrestrial Ecology, Banger. 2. Tree cores from Wytham indicated that mature Oaks grew best at high temp eratures and rainfall, but with low caterpillar populations. Young trees gr ew less well at elevated temperature, probably because they lost more water than they gained, Elevated temperatures advanced budburst, reduced foliar nitrogen and increased leaf toughness. 3, Moth eggs laid later or maintained at cooler temperatures than average r equired fewer heal units to hatch. Caterpillars rook up to 50 days to compl ete growth at field temperatures but did so in only 20 days at a constant 1 5 degrees C. 4. The mass of Tit chicks at day 15 (day 1 = egg hatch) was positively corr elated with temperature and negatively correlated with rainfall during the growing period, 5. At elevated temperature, budburst and moth egg hatch were synchronized, but earlier. Late feeding larvae and larvae fed on leaves from trees grown at elevated temperature produced smaller pupae. Pupal mass was unaffected w hen caterpillars and trees were maintained together under the same conditio ns. 6. Delaying egg hatch in Tits, to simulate conditions at elevated spring te mperatures, resulted in reduced chick mass, body size and fledging success. This occurred because die chicks were fed later and prey quality was poore r, because the peak of caterpillar biomass was missed. 7. We predict that moth reproductive output will be retained at elevated te mperatures because both leaves and caterpillars develop faster. Brood size in birds may be reduced because they cannot lay early enough to coincide wi th the narrower peak of food abundance.