Evolutionary ecology of marsupials: Life histories of the herbivorous marsupials

In this chapter we consider the life history strategies of diprotodont marsupials, marsupials which primarily depend upon plant tissues and plant exudates for food. In the previous chapter we assumed that the quality of food resources of marsupials which feed upon animal tissues was uniformly adequate and concluded that differences in the seasonality and predictability of supply were important in shaping their life history strategies. Here, however, we are concerned with animals whose food resources differ and vary markedly in quality as well as in supply (see Chapter 2), and for this reason we have chosen to review the life histories of diprotodont marsupials according to their feeding strategies. Feeding strategies and life histories Nectarivore The two families (Tarsipedidae and Burramyidae) represented in this category appear to have similar life history traits (Table 5.1). These small pygmy possums and gliders are the most fecund of the diprotodonts, usually producing two or three litters a year, each of two to six young. They are unusual among marsupials in that some species breed in the season of birth. Among these nectarivores the life history of Tarsipes rostratus is best documented. Births occur year-round in T. rostratus (Fig. 5.1), which is found in heathlands where flowering phenologies ensure substantial supplies of nectar and pollen in most months (Scarlett & Woolley, 1980; Wooller et al ., 1981). Some females produce at least two, and probably three litters a year. There is a nadir in females carrying pouch young in December, when flowering is least, and a peak in February-March, when flowering increases.