Sunday, February 13, 2011
Thanks to everyone who offered supportive emails and comments over the last few weeks. They were much appreciated. Even without family tragedies, I find this time of the year, February through March, the most bleak and difficult in Alberta. The winter has dragged on, the holidays are past, and it will still be two or three months until there is more than the faintest signs of life escaping from the icy shell. Sometimes one has to dig deep to find some winter bug interest.
The winter weather here derives mostly from the struggle between cold Arctic air masses moving south and warmer, moist Pacific air masses trying to force their way over the Rockies. Every now and then the Arctic air breaks away and drifts further south, bringing storms and snow to the US, but often letting in enough Pacific air to give us a brief thaw and a view of an overly optimistic fly, spider, or lacewing basking in the faint sun. The few days of warmth are appreciated, but the false springs are soon gone and below zero weather reigns again. Under the snow, however, there is a lot going on, and it is always worthwhile to shovel down and see what is up. On our last snow-delving trip to the Moose Pasture, we found something unexpected - a superfamily of tiny (3 mm) bugs we didn’t know we had – jumping plant lice Psylloidea.
In Australia, I would have called these lerps, or if being more formal, psyllids, but neither is technically correct. A lerp is actually a sugary covering of the larvae of some psylloids and a much appreciated food for some Australian birds, such as the infamous Bell Miner (Manorina melanophrys). You don’t have to go to Australia to see lerps – California is close enough to see the The Redgum Lerp (Glycaspis brimblecombei) devastating introduced gum trees. But fortunately no one has introduced the Bell Miner or it’s similarly aggressive but more flower-loving cousin the Noisy Miner to North America. The latter is slightly larger than a North American Robin, more aggressive than the Mockingbird (but lacks any musical ability), hangs out in gangs, and vigorously beats up and chases away any perceived competitor or threat. But at least they don’t farm psyllids.
'Psyllid' seems to be hanging on as a common name, although the Psyllidae of my youth is now Psylloidea (‘psylloid’ is a bit pedantic) and contains a number of families, depending on the authority. I follow Ian Hodkinson, not just because he did time in Alberta, but because he and J. Bird revised the subfamily Livinae (Aphelaridae) that includes my two snow-bound specimens. These psyllids are not lerpy, instead the larvae form galls on sedges (Carex) and rushes (Juncus). Some Livia species have been collected overwintering on conifers. The two I collected were from the litter of a white spruce under 40 cm of snow. Since psyllid workers don’t seem to have spent much time looking for their bugs under snow, it is possible that, at least in Alberta, this protected winter habitat is the actual overwintering site. Neither psyllid quite fits a described species, but little is known of the biology of psyllids unless they are pests. Seasonal polymorphisms are known in other psyllids and usually related to diapause, so I may have an overwintering morphology of a described species. Galls, polymorphisms, secret diapause sites, I never thought that such tiny bugs would prove such a welcome winter respite!
Thanks to The Atavism in New Zealand for opening my eyes to the new Psylloidea in a November post that prepared me to recognize them (I surely would have ignored them otherwise). While thinking of the southern hemisphere, let me say I’m happy to learn that Bunyip Co and A Snail’s Eye View (and her padymelons) survived Yasi and are back to blogging. I hope that is the last of the giant cyclones they have to experience.
For more on psyllids see:
Hodkinson ID. 2009. Life cycle variation and adaptation in jumping plant lice (Insecta: Hemiptera: Psylloidea): a global synthesis. Journal of Natural History 43: 65–179.
Hodkinson ID & J Bird. 2007.Sedge and rush-feeding psyllids of the subfamily Liviinae (Insecta: Hemiptera: Psylloidea): a review. Joumal of the Linnean Society 128: 1-49.