Food preference of the echidna, Tachyglossus aculeatus (Monotremata: Tachyglossidae), in the wheatbelt of Western Australia.

Abstract

Forty faeces samples of Tachyglossus aculeatus were collected for analysis from 10 haphazardly selected hollow logs of Eucalyptus salmonophloia (Salmon Gum) and E. wandoo (Wandoo) in two reserves in the wheat belt of Western Australia. The frequency of occurrence of termite species of the study area was determined by sampling the soil, mounds and dead surface wood; soldier-to-worker ratios were visually estimated at sampling sites. The ant fauna was assessed by pitfall trapping. The ratio of Formicidae to Isoptera numbers was 30% to 70%. No faeces samples contained 100% of either Formicidae or Isoptera. Nasutitermitinae (Tumulitermes, Nasutitermes, Occasitermes) accounted for 80% of all the isopteran soldier material (total numbers) and were found in 97% of the samples. Drepanotermes, Schedorhinotermes, Amitermes, Coptotermes and Termes accounted for the remaining 20% of total numbers ingested (soldiers only). Soldier-to-worker ratios at artifical breaks ranged from means of 20:1 for nasute genera to 1:30 for Termes. Relative differences in that ratio between termite genera were apparently maintained by T. aculeatus, and all abundant termite species occurred in the diet. The predominant Formicidae size group preyed on was 2-10 mm long, with 85% of individuals in the lower range of that size category. Large Formicidae (> 10 mm) were absent from the faeces, while small Formicidae (< 2 mm) occurred in low numbers. Species of Iridomyrmex 2-4 mm long accounted for > 75% of Formicidae numbers in pitfall traps. The data suggest that T. aculeatus may forage opportunistically, ingesting prey in proportions as encountered.