Studies of the sampling ofGlossina pallidipesAust.—II. The daily pattern of flies caught on cattle, in Morris traps and on A fly-round

Abstract

The first paper of this series (Smith & Rennison, 1961) compared the numbers of non-teneral individuals of Glossina pallidipes Aust. caught, on successive days in two experiments, by the use of tethered oxen, Morris traps and the standard fly-round technique. Only the total numbers of male and female flies were considered in that paper, although the catches were recorded for every 1^-hour period between 0800 and 1830 hr. (East African Standard Time); the present paper details the daily patterns of the catches. Materials and methods.The experimental area at Lugala, Uganda, the design of the experiments, the times they were carried out, the methods of catching and the personnel employed were described in the first paper of this series. For the comparisons described below the numbers of flies caught by each attractant per 1^-hour period (w) were transformed to log(w + l) (Williams, 1937). When a pair of traps was regarded as a single attractant the sum of the catches in the two traps was transformed, but where mean catches of traps of different colours was under consideration the number of flies taken in each trap of the pair was separately transformed. Wetand dry-bulb readings were taken with a whirling psychrometer every 1£ hours from 0800 to 1830 hr. during each experiment; moving averages of the temperature and saturation deficit were calculated from them. Results and discussion. The daily pattern of catches.Enough flies were caught in both replicates of Expt. 1 to permit re-analysis of the data to include lj-hour catching periods. The results already described (Smith & Rennison, 1961) were confirmed. In addition, the data indicate that the flies did not come to the tethered cattle and to the Morris traps randomly throughout the day (P<t)-001, for both replicates). The periods during which most males were caught differed from those in which most females were caught ( fig. 1). A definite difference from day to day in the numbers of flies caught per period of day (P<0-01, replicate 1; P<0-001, replicate 2) was probably referable to minor variations in weather; the effect was more pronounced in the second replicate, probably because the fourth day was persistently overcast and rainy. The interaction sex x period x attractant was not significant in either replicate, i.e., the pattern of catching did not vary for any individual attractant during the experiment; but the difference between the pattern of catches on oxen and that in traps ( fig. 1) was confirmed by the significance (P-<0-001) of the interactions period x attractant and sex x attraetant.

COMPARATIVE STUDIES ON THE DIURNAL ACTIVITY PATTERN IN TWO FIELD AND LABORATORY POPULATIONS OF GLOSSINA PALLIDIPES

“…The patterns obtained by Smith & Rennison (1961), Pilson & Leggate (1962) and Harley (1965) are similar to the results obtained in Nkruman, while results from Moggridge (1949), also working in the Kenya coastal area, are similar to the results from Mwalewa. The patterns obtained by Smith & Rennison (1961), Pilson & Leggate (1962) and Harley (1965) are similar to the results obtained in Nkruman, while results from Moggridge (1949), also working in the Kenya coastal area, are similar to the results from Mwalewa.…”

“…Most of the patterns obtained by other authors can be understood by the data presented in this paper. The patterns obtained by Smith & Rennison (1961), Pilson & Leggate (1962) and Harley (1965) are similar to the results obtained in Nkruman, while results from Moggridge (1949), also working in the Kenya coastal area, are similar to the results from Mwalewa. Jaenson (1978) reported a pattern similar to the pattern of flies from Mwalewa with flies from Kibwezi (Kenya), which were collected with a moving vehicle, but a pattern more similar to that of flies from Nkruman with flies collected in traps, especially in the hot dry season.…”

“…Curson (1924) found two activity peaks. Morris (1960) reported a midday peak, while Smith & Rennison (1961), Pilson & Leggate (1962), Harley (1965) and Jaenson (1978) reported major activity in the late afternoon. Morris (1960) reported a midday peak, while Smith & Rennison (1961), Pilson & Leggate (1962), Harley (1965) and Jaenson (1978) reported major activity in the late afternoon.…”

“…Williams (1943), Moggridge (1949) and Jaenson reported morning and afternoon peaks with a midday depression, and a higher morning than afternoon activity. Morris (1960) reported a midday peak, while Smith & Rennison (1961), Pilson & Leggate (1962), Harley (1965) and Jaenson (1978) reported major activity in the late afternoon. The differences in diurnal activity patterns were generally attributed to environmental factors, but Brady (1972) suggested for G. morsitans, that the pattern was largely under endogenous control.…”

“…The activity patterns of G. pallidipes in the field have been studied by several authors, using diverse methods of capture, such as traps (Morris, 1960;Smith & Rennison, 1961;Jaenson, 1978), cattle (Curson, 1924;Smith & Rennison, 1961;Pilson & Leggate, 1962;Harley, 1965), fly rounds (Williams, 1943 1949;Smith & Rennison, 1960, and moving vehicles (Jaenson, 1978). The activity patterns obtained vary considerably.…”