In a factorial experiment, fifth-instar Locusta migratoria (L.) (Orthoptera: Acrididae) were given either dry food (lyophilized grass) and drinking water, food only, water only, or neither food nor water. Food consumption and insect weight were measured daily, and the behaviour of each locust was recorded for 5 h on each of four consecutive days and for 2.5 h on the fifth. Consumption declined progressively in locusts given food only, and those given water only were not observed to drink after the first day of food deprivation. The decline in food consumption on the first day was accounted for by a decrease in the average duration of feeds, which remained constant thereafter. The further decline in consumption over subsequent days was due to a progressive decline in the number of feeds. Although food availability did not slow weight loss relative to locusts given neither food nor water, the availability of water without food did. The proportion of time locomoting increased in all deprivation treatments, but the pattern of change across the five observation days differed markedly between treatments. Locusts given food but no water increased locomotion from 20% of the time budget (the value for controls) to 30% on the first day of deprivation, and by the second day had reached a plateau of approximately 65%, which was maintained until the experiment was terminated on day 5. In contrast, locusts given water but no food approached the 65% level of locomotion on the first day, which was statistically greater than the 55% observed in those deprived of both food and water. This increase was due both to an increase in the number of locomotion bouts initiated and an increase in the average duration of locomotion bouts. On the second and third days, all deprivation treatments maintained locomotion at around 65%. By day 4, locomotion had decreased to approximately 15% in locusts deprived of both food and water, but not in those deprived of food only or water only. Unlike those given only food, locusts given only water showed a reduction in locomotion of c. 15% on the fifth day.

Many warningly coloured prey emit a conspicuous smell of pyrazines when attacked by a predator and it has been suggested that this odour cue constitutes part of the prey's aposematic anti-predator defences. The aim of the study was to test the hypothesis that pyrazine odours enhance the neophobic response of birds towards prey that is novel in appearance. Naive domestic chicks, Gallus gallus domesticus, were presented with food or water that was either familiar or novel (coloured with food dye) in appearance, in the presence or absence of five different odours. The odours in question were 2-methoxy-3-sec-butyl pyrazine, 2-methoxy-3-isobutyl pyrazine, almond oil, vanilla oil and thiazole. Presence of each of the pyrazines and of almond odour increased the latency with which chicks ate or drank, but only when the food or water was a novel colour. The effect was weaker with vanilla odour and absent with thiazole. When odours of 2-methoxy-3-sec-butyl pyrazine and thiazole were paired with a novel-coloured environment, eating and drinking were not inhibited. This suggests that odours naturally associated with chemical defence in insects or plants do enhance neophobia, but only when presented in conjunction with prey that has a novel appearance. However, confounding factors such as differences in odour intensity cannot at present be excluded. The implications of the results for theories concerning the evolution of warning coloration are discussed.

The optimum growth, food intake, food conversion efficiency, final body composition and mortality of juvenile Cichlasoma urophthalmus (Günther) was studied at different temperatures, ranging from 22.5 to 36.3°C. The results showed that food intake and specific growth rate increase rising to an apparent optimum at about 33.1°C. Multiple regression equations were derived which can be used to predict food intake and specific growth rate when temperature and initial body weight are known.