First Bugs of Spring!

We had our first day above 40 degrees since February 7, and our first day with above-average temps since February 11th. A midday hike at Van Patten Woods Forest Preserve produced one of these guys:

Diplocladius cultriger, 3/6/2012, Illinois Beach State Park

Well, maybe not this species -- today's wouldn't hold still long enough for a photo, and midges are difficult enough to ID with a good close look. On the other hand, the date's about right (this species appears to be an early riser, so to speak), so Diplocladius is probably as good a guess as any.

Most of the papers I can find on these guys are simple descriptive or taxonomic works (1) , but midges are so ubiquitous that they occasionally prove useful for more theoretical work. For instance, Broderson & Lindegaard used subfossil chironomids to examine the history of shallow lakes in the Netherlands. (2)

In an echo of my last post, Krosch & Cranston used chironomids to test the Gondwanan vicariance model of biogeography. (3) They were basically refining earlier work on dates of speciation and rates of evolution, and for the most part they confirmed that this group fits the vicariance model quite well. (Midges are very small and not very long-lived. They don't handle salt water well. Overall, it hardly seems surprising that they'd be poor candidates for long-distance dispersal events. Having said that, other truly surprising dispersals have been documented, so this wasn't a sure thing.) But they also found an oddity with regards to New Zealand. Speciation events seem to put the last colonization of New Zealand after its separation from Gondwana (favoring a dispersal scenario) but before the proposed "drowning" of the islands. If true, that would strongly suggest that the drowning wasn't complete, although the authors propose other possibilities as well.

Lofty thoughts, I think, over such a humble little critter.

(1) Saether, O. A. (1973). Four species of Bryophaenocladius Thien., with notes on other Orthocladiinae (Diptera: Chironomidae). The Canadian Entomologist, 105(01), 51-60.

(2) Brodersen, K. P., & Lindegaard, C. (1997). Significance of subfossile chironomid remains in classification of shallow lakes. In Shallow Lakes’ 95 (pp. 125-132). Springer Netherlands.

 

(3) Krosch, M., & Cranston, P. S. (2013). Not drowning,(hand) waving? Molecular phylogenetics, biogeography and evolutionary tempo of the ‘Gondwanan’midge Stictocladius Edwards (Diptera: Chironomidae). Molecular phylogenetics and evolution, 68(3), 595-603.