Onitis aygulus - A Winner

From: bertram lobert Date:  10/12/2008

Aygulus is going from strength to strength, in the Goulburn Broken catchment. I've previously noted (in this Forum) that this species was unknown across most of the Goulburn Broken, particularly the southern, higher rainfall half of the catchment, prior to about 2006. Since then I've been seeing more and more of them, though not many farmers had found them. Last season, in Feb-March, I found Aygulus in many districts, occasionally in large numbers. This season, several farmers have shown me specimens of this large beetle, not knowing what it was and not having seen it before. In one case, an observant farmer from near Kilmore, Vic (just north of Melb) described how he'd moved his cattle onto a neighbouring property that had previously had only sheep. In his words... "I moved my cows in at about 20:00hr (AEST) on the evening of 03 Dec 08. When I checked my cows early the next morning, about 06:00hr (AEST) on 04 Dec 08 to my surprise a number of the new cow pads had signs of Dung Beetle activity around them. One to two dirt excavations around the edges of several pads. "Each day I check the cows, there seems to be more Dung Beetle activity. This morning (Mon 08 Dec 08) I took a square mouth shovel. To my surprise I came across a cow pad with about five excavation heaps and when I took a shovel to the Pad with some of the top soil, I was able to count without difficulty 12 holes. There were a few more that had their entrances covered as I removed the top soil." The unconfirmed culprit was Onitis aygulus - see the farmer's photo (though I'll check the ID when I get specimens). This farmer had not seen the beetle at all in previous years but, presumably, it was present in good numbers somewhere in the district. It demonstrates just how quickly things can change locally, even when it's a large, 'slow-breeding' beetle like Aygulus.