THE PHENOLOGY OF HEXACENTRUS MUNDUS 
(F. WALKER) AT WAU, PAPUA NEW GUINEA 
(ORTHOPTERA, TETTIGONIIDAE) 
By Michael H. Robinson 1 and Thane Pratt 2 
Introduction 
When at Wau, Morobe District, Papua New Guinea, during 
1970- 1 971, the senior author was impressed by the very distinctive 
nature of the stridulation of a common tettigoniid Hexacentrus 
mundus (F. Walker). No attempt was made to study the species 
at this stage but it was encountered frequently during other re- 
searches and males appeared to be stridulating throughout the entire 
year. Phenological studies of the spiders at Wau (Robinson & 
Robinson, 1973; Robinson, Lubin & Robinson, 1974) showed that 
adult spiders of several species were active and reproducing through- 
out the year and gave rise to the suggestion that tropical arthropods 
may be less seasonal at middle altitudes than they are in the low- 
lands. Nearly all the sparse data on the phenology of tropical in- 
sects come from lowland study areas (see review in Robinson, Lubin 
■& Robinson ibid.). We therefore decided to census the number of 
singing male H. mundus that were audible from three line transects 
located at around 1066 meters altitude. We carried out this survey, 
weekly, for one year (January 1974 to December 1974). We orig- 
inally chose to census H. mundus because its song sounded unique 
among the orthopteran stridulations at Wau; it turned out to be 
a lucky choice since the insect is almost certainly predatory and there- 
fore more interesting for comparisons with the spider data that are 
already available from this locality. Stridulation is essentially a 
sexual activity and the census should provide an index of repro- 
ductively active individuals. It showed that males were active in 
every one of the months of the year. 
Materials and Methods 
The species 
The species was identified by Prof. I. J. Cantrall, Museum of 
Zoology, Ann Arbor, Michigan, to whom we are most grateful. 
Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Panama 
Canal Zone. 
2 Wau Ecology Institute, P.O. Box 77, Wau, Papua New Guinea. 
Manuscript received by the editor September 15, 1975. 
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