A comparative study of communication in six taxa of Southern African elephant-shrews (Macroscelididae)

Aspects of olfactory, auditory, visual and tactile communication were investigated in five Elephantulus species (E. brachyrhynchus, E. edwardii, E. intuft, E. myurus, E. rupestris) ar.d Macroscelides proboscideus, facilitating comparisons among species and genera. The
purpose of this study was to determine whether species specific patterns of communication could be identified in the southern African elephant-shrews.
Scent galnd structure and location was investigated to determine whether species specific differences existed and to relate gland location to marking behaviour. Prominent scent glands were found in the oral angel, foot pads, anogenital region and tail of all elephant-shrew specIes. Marking behaviours such as sandbathing, digging and anal dragging correlated strongly with sent gland location, but no glandular size and/or structural differences were apparent among the different elephant-shrew species. Species specific differences in marking frequencies did exist among the six elephant-shrew taxa, but were unrelated to glandular development. Choice chamber preference tests indicated that Elephantulus species preferred conspecific odours, with males showing higher levels ofdiscrimination than females.
Audible vocalizations and footdrumrning were investigated and compared in the sex elephant-shrew taxa. Distinct differences were present in the acoustic repertoires of the southern
African elephant-shrew species. Footdrumming showed very clear species specific patterns, and footdrumming characteristics were compared with an existing morphological phenogram to derive a possible path o f evolution for footdrumming.
Visual and tactile communication were investigated by analysis of frequencies and sequences of behavioural acts. A comparison of male-female interactions of the different taxa showed differences in behavioural frequencies both between males and females of a species, and among the different species. Discriminant function analysis showed clear species specific patterns in the visual! tactile signalling systems of southern African elephant-shrews, and this
was more clearly defined in males.
Elephant-shrews showed higher levels of aggressive behaviour in interspecific encounters, indicating a possible role of aggression as a premating isolating mechanism between species. However, no differences in aggressive behaviour between allopatric and sympatric male- female interactions could be discerned . Elephant-shrew males showed high frequencies o f
submissive behaviour in intraspecific encounters, which may be a strategy to reduce aggression in conspecific females.
Species specific patterns of behaviour were found to exist in all three modes of communication investigated, and may all act to some extent as premating isolation mechanisms between species. However, many of these patterns are very subtle and it is suggested that a combination of all sensory modalities act together to form each species' signalling system.