DayTripper on May 30, 2013May 30th, 2013, 4:17 pm EDT
Collected this guy on a northern Michigan trout pond last night. Found it struggling on the surface in the middle of the lake. Not sure if it just emerged or if it fell in while flying over. Anyone know how to tell what the sex is on these? I am also curious what genus/species it might be. Thanks!
DayTripper on May 30, 2013May 30th, 2013, 4:59 pm EDT
According to the crane fly page here on troutnut,
Craneflies pupate for one to three weeks. The species which do so in the water then swim to the surface to emerge in the style of caddisflies, and are presumably vulnerable to trout, though I have not read about good fishing during these events.
Swisher and Richards in Selective Trout say the larvae all crawl out of the water to pupate, conflicting with the above account. There are so many species that it seems likely both behaviors occur in some species."
I checked a half dozen other websites and all say that they crawl onto land. In Matching the Hatch, Schweibert references species that pupate and emerge in the water (late mornings). McCafferty also references that there are species that pupate in water, but doesn't go into much detail.
Definitely a female - males have much more complex parts. Is that a metric or english rule? I see the 10ths but I have an english rule in 10ths so thought I would check. If english it is likely one of the Tipula. If metric I suspect there are some other genera that large. Tipula are not typically pond forms, more likely the marshy areas surrounding the pond.
Ok I'm definitely not an expert but the elongated abdomen of this female narrows it down somewhat and after running it through the key, I'm somewhat confident in my determination... Definitely Tipulidae, probably Tipula dorsimacula. Pretty common from what I read and very widespread distribution. One generation a year. If it is T. dorsimacula, it is a terrestrial species (the ovipositor is a clue to that) that probably just fell into the water.