Xylocopa Aerata - Golden Green Carpenter Bee

The Golden Green Carpenter Bee (Xylocopa aerata) has been more abundant this year than previous years. A lot of its habitat was destroyed in the bushfires of 2019-2020 and it seems to have taken until this year to recover. For the last 3 years I have actively looked for them and found them infrequently. This year is different, along the tracks I frequent in Vincentia I will see them on every sunny day and will see them in multiple locations on different flowers.

These bees nest in grasstrees or upright deadwood of softwood trees like banksia and casuarina. Unfortunately, this type of vegetation is easily destroyed in fires and is one of the reasons they are considered a vulnerable species. They were one abundant in South Australia and Victoria but are now extinct in these areas. They are now restricted to the Sydney basin and south coast and one area of Kangaroo Island in SA. There are 276 observations on iNaturalist, which also shows their distribution.

They are a striking bee with bright metallic colouring. The female is on the flower and being approached by a male. They are larger than the western honeybee and often heard in flight before they are seen. There is another similar species the Peacock Carpenter bee (Xylocopa bombylans) which seems to be more abundant and distributed from Sydney north along the coast. According to Houston the easiest way to distinguish the two species is from the male facial features. This one shows the features of X. aerata.

Females excavate their nest in deadwood by hollowing out a tube in the deadwood and starting from the end away from the entrance deposit a patty of pollen and nectar. An egg is laid on the patty and that part of the tube sealed before the process is repeated.

The females visit flower patches throughout the day to collect the pollen and nectar and take it back to their nest. Males patrol the flower patches and can be seen flying from one flower to the next searching for females. After patrolling they will rest for a short period before beginning another patrol. On finding a female they will hover close to see if she is receptive. The bee above was not receptive, initially ignoring the male and then physically attacking him when he got too close. The pictures below show a receptive female.

On this occasion she was receptive and grabbed the flower with one leg and hung below. As the male approached another male can be seen looking for his opportunity. This resulted in the two males trying to knock each other out of the way and neither was successful. The picture below taken on a different day shows the male grabbing the female from behind. Unfortunately, at that point they went out of sight and I lost them as I tried to maneuver through the bushes to get a better picture. About 20 - 30 seconds later they flew away individually.

It took me a while to find a nest and I was eventually lead to it by a male. On a day when males were prolific patrolling the flower patches I was surprised to see one being very active in an area of the forest away from the native peas they normally patrol. Closer examination showed him flying around this tree stump and being particularly interested a hole halfway up the stump. The stump is an old casuarina tree and the rest of the tree has broken off and is lying to the left of the stump. It is 1.2 metres high and the hole is 55cm from the top. It is in an open area of the forest 4 metres from the track. After watching the male for a couple of minutes I went in for a closer examination.

Eventually the female came to the entrance but quickly retreated when she saw me. The entrance is 1.2cm diameter and the distance from the bark surface to the back of the hole is 2.5cm. It then turns at right angles down the stump. At this point the stump is 7cm across but not a perfect cylinder and is less deep. The hole is facing almost exactly due west.

The following day I again visited the nest and on this occasion was able to get these three pictures of her entering the nest after foraging. She was in the nest 3 minutes before she came to the entrance but would not leave until I moved back to track. She appears to be the only occupant of the nest.

Having now seen the nest I can see why they are a vulnerable species. This year they have been prolific; however this part of the forest was designated for backburning and this would have occurred if we had not had such a wet winter. Unfortunately, when the area is backburned this nest is likely to be destroyed as it is at ground level and a dead stump will have no protection against the fire. Until then I will continue to observe the nest and update this blog as appropriate.

Update 28 September

Now I can be certain there are two females in the nest and probably three. Saturday 27 September was a warm day with temperatures in the high 20's deg C and the bees were active. These two pictures were taken just over a minute apart and show bees entering the nest chased by a male who had been cruising near the nest. I was watching the nest the whole time and no bee exited the nest between the two bees entering.

I had arrived at the nest 7 minutes before and from the track saw a bee enter the nest. A minute later when I was at the nest one bee exited. No other bee entered or exited until the two in the pictures. It is unlikely the same bee would have exited so quickly which leads me to believe there are at least three bees using the nest. Whether they are cooperating females or progeny is unknown.

Update 7 October 2025

I have now found another two nests around 150 metres from the original nest. Again I was lead to them by the active males. Both are in a dead Casuarina stump about 3 metres off the track. The original nest which appears to have 2-3 bees is 50 cm from ground level and faces due west. The second nest is 20cm above and facing southwest.

The second nest is being excavated and has a large amount of sawdust on the tree below the opening. It is possible the nest below became too crowded and one bee has started the construction of a new nest above the original nest. She is excavating using her mandibles and then pushes the saw dust back up the nest and out the entrance using her rear legs. The picture to the right shows her ejecting sawdust. This has been going on for a few days and I have not seen her enter or leave the nest in the times I have visited.

Reference. Terry Houston "A Guide to Native Bees of Australia" CSIRO Publishing 2019