ethology of the pollen wasp Rolandia maculata 
345 
figure 3 Profile of head and forebody of Rolandia 
maculata female showing long setae 
comprising the psammophore (shorter, 
generally distributed setae omitted for 
simplicity). Scale line 1 mm. 
and herb roots and deeper still was uniform yellow 
gand. The soil was damp throughout as a result of 
heavy rains preceding excavation. 
Phenology 
Comparatively few WAM and WADA specimens 
(other than those originating from this study) are 
labelled with their collection dates. Those with 
dates (both sexes) were collected in the months of 
December and January in various years. 
On the first occasion I observed adults in Kings 
Park (17 November), both sexes were numerous at 
flowers of Jacksonia species and over the section of 
fire access trail described above. Many females 
were searching over the surface of the trail, some 
alighting intermittently to make exploratory 
excavations, while two other females were well 
advanced in excavating burrows. All specimens 
collected in November 1992 had entire wing 
margins indicating recent emergence (most 
specimens collected in December and January 
show slight to marked fraying of wing margins). 
Clearly, it was then early in the nesting season but 
probably activity had begun at least several days 
prior. A week of electrical storms with strong wind 
and heavy rain followed the first visit and must 
have caused a heavy mortality for, on my 
subsequent visit (24 November), only one male and 
one female were observed over the nesting site and 
only a few individuals were encountered each visit 
thereafter in December and January. No adults at 
all were observed during the February visits when 
the forage plants had few flowers remaining and it 
was evident that the nesting season had finished. 
In summary, the available evidence suggests that 
the flight season of R. maculata extends from mid 
November to mid January. 
Nest architecture 
Burrow entrances were simple holes in the sand, 
without any form of turret, reinforcement or 
closure. Several burrow entrances observed were 
partly concealed beneath some small object on the 
ground such as a sheoak fruit, a twig or fallen grass 
stalks, while two were quite exposed in bare sand. 
All burrows entered obliquely at about 30° below 
horizontal. Five nests were excavated. In each 
case, the burrows had been marked after R. 
maculata females were observed entering or leaving 
them. The oblique entrance galleries curved 
downwards sharply into vertical shafts which were 
horizontally displaced from the entrances by 2-3 
cm (Figure 4). Entrance galleries and the shafts 
below them were 4-5 mm in diameter, round in 
section, unlined and uncemented. Freshly 
constructed brood cells were found in association 
with two shafts at depths of 28-32 cm, well into 
the yellow sand zone. No brood cells were found 
near the first shaft excavated which extended to a 
depth of only 10 cm and was plugged with white 
surface sand in its upper half. It appeared to have 
been abandoned while incomplete. 
The second nest had one open cell at the lower 
end of the shaft The cell was a 2 cm long lateral 
extension of the shaft and was not formed or lined 
in any detectable way. Resting on the floor of the 
cell at its inner end was a partially completed 
provision mass bearing a first instar larva and a 
flaccid egg chorion. 
Three cells were located near the lower end of 
the third shaft (Figure 4). One, which was open 
and contiguous with the shaft, contained an 
elongate egg lying transversely across the inner 
end and a newly initiated provision mass. The 
other two cells were slightly deeper, closed and 
contained completed provision masses with 
feeding larvae. The cells radiated out in different 
directions and up to 3 cm from the shaft. Long 
axes of two cells were horizontal while that of the 
third was oriented 45° below horizontal. 
The fourth and fifth nests excavated were 
marked while still open and occupied in early 
December and early January, respectively, but had 
been completed and deserted by their makers at 
excavation in February. Only the upper sections of 
the shafts which were filled with white surface 
sand could be traced but several cocoons were 
sieved from blocks of sand cut from 20-40 cm 
below the entrance of each nest. Two distinct kinds 
of cocoons were recovered. Three cocoons of one 
kind (presumed to be those of R. maculata) 
contained mature defaecated larvae while five 
others were old, vacated and sand-filled. Three of 
these vacated cocoons are believed to have been 
made by Hyptiogaster larvae (see Associated 
Organisms). 
