科研之友
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摘要
Avian frugivores may select fruit based on their seed loads and pulp-to-seed ratios, and this may have important implications for their role as seed dispersal agents. Consequently, the effect of different seed packaging was investigated in two relatively large South African frugivores, Knysna (Tauraco corythaix) and Purple-crested (Gallirex porphyreolophus) Turacos. Small-seeded artificial fruits containing on average five black plastic beads (2.24 mm diameter) and large-seeded artificial fruits containing on average one single black plastic bead (3.85 mm diameter) were used to investigate minimum transit times and food preference. The total seed volumes of the two fruits were on average approximately equal (29.42 and 29.88 mm(3) for small- and large-seeded fruits, respectively). Bead minimum transit times ranged from 38 to 45 min for Knysna Turacos and 36 to 50 min for Purple-crested Turacos, with faster minimum transit times on the small-seeded diet. Pulp minimum transit times ranged from 25 to 39 min for Purple-crested Turacos and 34 to 40 min for Knysna Turacos. Purple-crested Turacos had significantly shorter pulp minimum transit times on the large-seeded than the small-seeded diet, whereas Knysna Turacos showed no significant difference between diets. Knysna Turacos preferred the small-seeded to the large-seeded artificial fruits, whereas Purple-crested Turacos showed no preference for either diet. Further studies on avian dispersers will contribute to a greater understanding of their evolutionary relationship with fruiting plants. In particular, future studies establishing suitable seed sizes and volumes for use in determining the effect of seed packaging on larger birds are required, and studies looking at seed packaging of indigenous forest fruit and the effects of seed packaging on digestion and food preference in indigenous avian frugivores may give insight into the role of avian frugivores as fruit consumers and seed dispersers.
- 出版日期2011-1
