Monday, July 27, 2009

Lab Excitement

It got a little exciting in the lab today. A live, giant beetle and a dead parasite made my day much more interesting than the average Monday.

Jeff Boettner and Craig Hollingsworth showed up around lunch time with a Tuppermaid (or Rubberware, I always get those two confused) container holding a magnificent specimen of a pine sawyer. A woman brought the insect to Craig, thinking it might be a grasshopper because of the long antennae. Neither Craig nor Jeff had seen this particular species before, though it was obvious to them it was no grasshopper.

Consulting BugGuide, we eventually reached a consensus that the insect was a male “northeastern sawyer,” Monochamus notatus (Drury). Female sawyers have much shorter antennae, and shorter front legs. According to the Field Guide to Northeastern Longhorned Beetles by Douglas Yanega, this species ranges from 23-35 millimeters in body length. This one was every bit of that. Northeastern sawyers occur pretty much east of the Rocky Mountains and bore in dead and dying conifers as larvae, favoring pines. Harvested firewood can yield the beetles indoors when they emerge in stored situations. This specimen is now destined to be pinned for posterity in the University of Massachusetts insect collection. I suppose it achieves something close to immortality in this case. Hopefully more live specimens will show up, as most of my impromptu images did not turn out very well.

Another interesting find came as I was sorting leafhopper nymphs and other hemipterans preserved in alcohol from pitfall traps. One of the nymphs had some kind of dark object attached to its underside, between the first and second pairs of legs.

It turned out to be the larva of a dryinid wasp (family Dryinidae), bizarre parasites of leafhoppers and some other insects. One of the effects of ethanol on dead insects is a clearing of the pigments in some specimens, and increased magnification clearly shows the larval dryinid curled inside a capsule-like pouch.

Adult dryinids are even stranger than the larvae. Females are often wingless, and sport scissor-like front feet used for gripping the leafhopper while an egg is laid on it. The adult wasps have also been observed catching, killing, and half-consuming prey instead of using it as a host for their offspring. For more images of both larvae and adults, please see the BugGuide reference page and Alex Wild’s fantastic images of an adult female.

Hm-m-m-m, I wonder what tomorrow will bring?

2 comments:

  1. Very cool beetle! The info on the dryinid is fascinating. Thanks for sharing!

    Janet

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  2. Just found one at dusk (stoughton, MA)- pretty huge. Its in a mason jar right now…. a pretty impressive creature….

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