Australia’s “Marsupial” bee

Author Ken Walker ◦

Australia’s “Marsupial” bee — a world first.

It is known that female bees carry mites on their body. While these mites are on the bee, they are in the non-feeding dormant stage called hypopial nymphs. Once the female bee has provisioned her brood cell with damp pollen, she sealed up the cell. This is a bit like putting a damp sock into a sealed, plastic container- it soon goes mouldy with fungus. Now, before the female seals her brood cells she scrapes a few of the dormant, hypopial mites into the brood cell. The rise in humidity inside the sealed brood cell, stimulates the dormant mites to wake up, complete their development and mate but importantly, they eat the fungus inside the brood cell which keeps they brood cell clean. Female furrow or Lasioglossum bees generally carry their mites on the dorsal surface of the first segment of the abdomen or metasoma. In some bees, they provide a sticking pad for the mites to attach. This mite carrying area is called an acarinarium. In some Lasioglossum bees, the acarinarium is a bare, raised boss in the middle on the basal area of the first segment and it is usually surrounded by hair. The hypopial mites have anal suckers which they use to clamp their body to the acarinarium and they arrange themselves in a fan like array.

This is all known and documented. I can now add a new piece of information to this puzzle. I have found a Lasioglossum species, Lasioglossum (Ctenonomia) picticorne, in which the male transports the mites on the underside of his abdomen and presumably transfers the mites during mating to the dorsal surface of the females’ first abdominal segment. I have checked with bee colleagues around the world and this is the first record of a male Lasioglossum bee carrying mites. The male has developed a “pouch” or “invagination” or “fold” underneath abdominal segment three in which the mites sit. The mites line up in rows inside this male pouch with their legs pointing outwards. We do not know what stimulates the mites to transfer from the male to the female.

The images show: (image 1) a female bee with an arrow showing where the mites sit on her dorsal surface; (image 2) a male bee with an arrow showing where the males carry the mites; the acarinarium with a bare, raised boss on the dorsal first segment of the female without mites (image 3) and with mites (image 4); and finally, the male bee with mites jam packed inside his “marsupial pouch” (image 5). We learn new aspects of animal behaviour every day. Thought I would share this discovery before I publish it. Enjoy.

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