Effect of food quality and availability on rainforest rodents of Sri Lanka

Tropical rodent communities are highly diverse species assemblages, yet remain poorly studied. This investigation was conducted with the objective of examining the responses of rainforest rodents to food quality and availability. These factors were assessed through laboratory and field trials conducted in the Sinharaja and Kanneliya rainforests in Sri Lanka. The effect of food quality on the foraging behavior of rodents was examined through feeding experiments using natural rainforest fruits/seeds. In addition, the effect of food augmentation on the rodent population was also investigated. Diet choice experiments showed that rodents exhibited clear food preferences, with certain fruit types being preferentially consumed and others rejected. Tolerance tests where animals were provided with a single fruit type showed that some items that were avoided when offered with a range of food items were consumed when no alternatives were available. In the field a positive relationship was found between fruit/seed and rodent densities; seed addition resulted in marked increases in rodent numbers. These results suggest that tropical rodent populations are food limited, at least during seasons when fruits/seeds are in short supply. Food selectivity also means that populations of rainforest rodents might be adversely affected by changes in tree species composition resulting from habitat disturbance and fragmentatio

Parasitic associations of a threatened Sri Lankan rainforest rodent, <i>Mus mayor pococki</i> (Rodentia: Muridae)

Parasitic investigations of the subspecies Mus mayori pococki were carried out in four rainforests that included two man and biosphere reserves and two forest reserves of Sri Lanka from October 2006 to August 2007. Rodents were live-trapped using Shermans traps. Of the 117 individuals of M. m. pococki captured 73% were infested with four types of ectoparasites mites of the genus Echinolaelaps, a louse Polyplax serrata, a larval stage of hard tick Ixodes and pseudoscorpions of the genus Megachernes. Mites were the most abundant ectoparasite of this rodent host. Faecal examination revealed the presence of a nematode larva of the Order Strongylida and five types of parasitic ova; three nematode ova types i.e. strongyle, strongyloides, ascarid types, and cestode and mite ova. In comparison to the non-infested hosts, those infested did not show a significant difference in body weight and size. Both sexes had an equal probability of being exposed to ectoparasites. The present study on the parasitic investigations of M. m. pococki reports four new host-ectoparasite and six new endoparasitic records for the Sri Lankan rodent host