Insufficient use has been made of ecological data concerning potential hosts in studies to determine the life cycles of zoonotic parasites and pathogens. Factors such as the geographical distribution of hosts, the altitudes at which they live, their affinities for specific habitats, their vertical distribution within the habitat, and the periodicity of their activities have bearing on the hosts' predisposition to involvement in disease cycles. Diets and feeding habits may determine the likelihood of acquiring infection. Reproductive characteristics determine whether a species is suitable as a reservoir or as an amplifying host. Behavioral factors, such as selection of a particular kind of nest site, may also predispose the involvement of the host with parasites and pathogens. Behavior patterns may determine the maximum population densities of hosts. Estimates of population sizes, of relative abundances of species, and of the involvement of species in disease cycles may be strongly influenced by the collecting and sampling methods that are used and also by the behavioral response of the mammals toward collecting devices, such as traps.
The Noctuid Calpe [Calyptral] eustrigata Hmps. was reported as a skin-piercing blood-sucking moth for the first time in Malaya (Bänziger, 1968) and is so far the only lepidopteran proved to suck blood by means of a piercing act. A few field observations and the description of the piercing behaviour of caged moths were given. Apart from a taxonomic study of the genus Calpe (Berio, 1956), a single record (Büttiker, 1969) and some notes on the moth's proboscis and possible evolutionary pathway (Bänziger, 1970, 1971, 1972) to our knowledge no other data have been published on the moth after its description as a new species (Hampson, 1926). The life cycle is completely unknown. From the scanty museum specimens available, it appears that the species inhabits South and Southeast Asia. A closely related, though less rare species, the fruit-piercing C. thalictri Bkh., has been used for a detailed study of the piercing mechanism likely to be adopted by Calpe (Bänziger, 1970); the feeding turned out to be as unusual as the feeding habits. Little or nothing is known about other Calpe species. C. eustrigata is not the only adult lepidopterous parasite of mammals. Lachryphagous ("eye-frequenting") moths feed as "marginal" parasites upon eye-secretions of ungulates, elephants and occasionally man (Shannon, 1928; Reid, 1954; Büttiker, 1964, 1967; Bänziger, 1966). Arcyophora species and the eulachryphagous Noctuid Lobocraspis graseifusa Hmps. which apparently feeds exclusively upon eye discharges, are suspected as vectors of eye diseases (Guilbride et al., 1959, Büttiker, 1964; Bänziger, 1972). While no lachryphagous moth is able to suck blood by a piercing act, there are a number of facultative lachryphagous moths which lick up the blood freely present at wounds, or that excreted anally by mosquitoes (Bänziger, 1969, 1972). Because of the scientific interest in C. eustrigata, research has been carried out to investigate different biological aspects of the species in Malaysia, Thailand. Laos and Indonesia (May 1971-May 1973). The first account presented here will be continued with a paper (in prep.) on the piercing mechanism and soon, it is hoped, with more information on the physiology, life cycle and medical importance of the moth.
Long-term observations are presented on the behaviour of the siamang ape, Symphalangus syndactylus, in the lowland forest of central Malaya. The data were collected during two dry and three fruiting seasons between 1969 and 1973 inclusive on two groups with adjacent ranges; comparisons are made within and between sample periods, and between groups. The influence of weather on daily activities is considered. Food intake is analysed in terms of number of food trees, number of visits to these trees, and the cumulative time spent feeding on various food categories. Ranging behaviour is investigated in terms of distance travelled, area covered, and distribution of time and of food trees about the range. The occurrence of calling is described and compared with that of the white-handed gibbon in the same area. A discussion ensues on each of these aspects of behaviour in turn. Emphasis is laid on the similarity of behaviour of the two groups at any one time, and on the degree of their response to the fluctuations of environment variables. Finally, the application to siamang of ranging concepts currently used in animal behaviour is considered briefly.
Wild, adult siamang were observed for over 800 h in lowland dipterocarp forest in the Krau Game Reserve, Pahang, West Malaysia. Siamang use four patterns of locomotion: brachiation, climbing, bipedalism and leaping. The pattern of locomotion used by the siamang varies with the size of arboreal supports and with major behavioral activity. Travel is primarily by brachiation along large boughs. Locomotion during feeding is primarily climbing among small branches. In feeding, siamang use suspensory postures among small supports and seated postures on large supports. Comparison of siamang locomotion and posture with that of other apes suggest that quadramanous climbing during feeding is the basic hominoid locomotor adaptation.
1. Of the scarce Calyptra minuticornis, C. orthograpta and C. labilis, 51, 24, and 7 adults, respectively, were observed during some 600 night inspections at over 100 sites in 1965--1967 and 1971--1977. 2. Hitherto biologically completely unknown, and not recorded before in S.E. Asia, the latter two species flew in or near tropical monsoon forests in hilly regions (300--600 m) of N. Thailand (C. orthograpta also N. Laos). C. minuticornis was found in these and in tropical evergreen and semi-evergreen rain forests of S. Thailand and N.W. Malaysia. 3. In N. Thailand the three species were more common at the end of the cool season/start of the hot season and at the start of the rainy season. They were active mainly during the first half of the night 4. Flight and piercing behaviour, alighting, resting, enemies, and the lack of females, were similar to virtually identical with the "classical" skin-piercing blood-sucking C. eustrigata. 5. C. labilis was seen attacking elephant, C. orthograpta also water buffalo and sambar, C. minuticornis also zebu and tapir but not sambar. C. minuticornis settled on man also but did not pierce. 6. Through no piercing of hosts' skin has actually been seen in nature, indirect evidence suggests that the 3 moths are likely to be occasional blood-suckers. They pierced and sucked blood from the author's skin in experiments. 7. Reasons for lack of direct evidence may be: less developed hematophagy, less favoured hosts, lack of easy-to-pierce injured skin (which also trigger the piercing response), different climatic and phytoecological environment, fewer specimens than in the case of C. eustrigata. 8. Field observations and experiments indicate that the closely related, fruit-piercing Oraesia emarginata is not skin-piercing blood-sucking--a habit likely to be exhibited mainly in humid equatorial regions by a few Calyptra only.
Sympatric gibbon species Hylobates lar and H. syndactylus were censused on a mountain in Malaya (West Malaysia). Habitat quality was assessed between 380- and 1,525-m altitudes. H. syndactylus was found to occur up to altitudes higher than does H. lar, and this is discussed with reference to the two species' divergent foraging strategies indicated by previous research. It is suggested that gibbons are restricted in their altitudinal range by an increasingly unfavourable ratio of food consumed to energy expended in its location, caused by a reduced food-source density and more difficult terrain at higher elevations.
The monthly medians of the distances traveled daily by siamang and lar gibbons are negatively correlated with rainfall and positively correlated with the separate and combined abundance of different food categories. The latter correlations indicate that the apes follow a policy of cutting their losses by reducing travel when food abundance falls.
The rickettsial disease of man found only in Asia is mite-borne (scrub) typhus, caused by Rickettsia tsutsugamushi. Unique to southern Japan is a little-known human mononucleosis-like disease caused by Rickettsia sennetsu. In 1981 and 1982, there was a remarkable resurgence in the number of reported cases of mite-borne typhus in Japan after some years of virtual absence. Recent studies of R sennetsu have resulted in its reclassification to the genus Ehrlichia, members of which until now have been exclusively pathogens of animals. The historical background of ecologic investigations, in Malaysia and elsewhere, of these two developments suggest directions for future research.
Using seven methods of surveillance, 58 species of mosquitoes from nine genera were in Pantai and the two neighbouring villages during two visits in 1982. Ma. bonneae was the most prevalent species attracted to man. In the forest shade Ma. bonneae and Ma. dives showed activity throughout the 24 hours with peak biting during 1900-2100 hours. An. balabacensis exhibited peak activity shortly after midnight. Inside and outside house, Ma. bonneae showed similar activity except that it ceased during the day. Mansonia was only mildly zoophilic. CDC light traps gave poor yields of mosquitoes. Pyrethrum spray catch inside houses early morning did not include any Mansonia. Outdoor day resting catch included Ma. bonneae fed on man. Transmission of Brugia, probably human filariasis, by Ma. bonneae occurred in Pantai and in the two neighbouring villages. One infection in Ma. dives was found in Pantai. The monthly infective biting rate and monthly transmission potential for Ma. bonneae were estimated at the forest shade and outside the house in Pantai.