Sunday, June 19, 2011

Aculeata Agonistes: Soggy Mud Daubers & Muddy Thinking

 I think I watched too many Walt Disney wildlife programs when I was a child, because this wasp looked sad and soggy to me this morning (and yesterday and the day before too). But I know I’m just projecting my feelings onto the mud dauber: there is no data supporting the hypothesis that insects feel emotions like people and cats do.
 This particular mud dauber is Ancistrocerus waldenii (Viereck, 1906) and she was thriving when the sun was shinning.
 There isn’t any common name associated with the species on BugGuide or at the Identification Atlas of the Vespidae (Hymenoptera, Aculeata) of theNortheastern Nearctic Region. Since the species seems to have been named after someone called Walden (or perhaps Walden Pond), I think Walden’s Mud Dauber will have to do.
 The generic name seems to be derived from the Greek ancistrum (fish hook) and cerus (an earthen pot). I suppose the former refers to the female’s curved sting and the latter to the mud nest. Walden’s Mud Dauber’ free-standing mud nests, however, are unusual among at least the local Ancistroceri – most nest in hollow twigs and use mud only for the partitions between cells.
 Given the last week of steady rain, one can see the advantage of a retreat less likely to dissolve back into the earth from which it sprang. Perhaps the wasp mixes in some hydrophobic material or cement as she works the mud into the scimitar-shaped additions which she stacks into tubular cells. I also wonder if they know bad weather is coming? After making a half dozen tubes perpendicular to the ground, and open to any rain until they were capped, this wasp constructed a tube on top of the others and parallel to the ground.
 The last few days, the wasp has been spending most of her time in this tube, glumly watching the rains fall. That’s a shame, because the caterpillars she was hunting included a nasty little vermin that makes a mess of our Ivory Halo Dogwood each year. Here's a paralyzed one that I rescued from a foraging Formica ant - it is dangerous to leave you brood cells open.

A larger caterpillar also taken is probably the Delphinium Leaftier (Polychrysia esmeralda (Oberthür, 1880)). 
 Interesting that she seems to go after caterpillars that hide themselves in folded bits of their host plants.
 It would be a terrible shame, if after all her hard work, this poor mud dauber had to watch her babies wash away in a sea of mud. This may be more Disneyesque thinking, but I prefer to think of this as a proactive measure of classical conservation biological control. Keep your parasites, predators (and pollinators) happy and you will have a thriving Home Bug Garden. I give you the first mud dauber umbrella (patent pending).

Saturday, June 18, 2011

Sunday Sawfly: Inspired by Thrifty Thursday

 One of the benefits of the long, long days around the Summer Solstice at a northern latitude such as Edmonton's is that even when the weather is miserable most of the day, a hour or two of sunshine may peak through the clouds. That may not happen this rainy Saturday, but it did during yesterday's downpours and the cool conditions were a good time to get close to some bugs. Below is the original (reduced in size for posting) image of one such shot and above my best attempt at making it interesting. The sawfly is possibly Pristiphora appendiculata (Hartig)(=rufipes Lepeletier) - the Small Gooseberry Sawfly which my wife caught ovipositing for a previous posting.
I'm not much of a bug photographer - just an upper mid-range point-and-shoot (Lumix DMZ FZ28) documentor of the Home Bug Garden. The good pictures you see here are usually from my wife's Nikon D-70 DSRL - old, but reliable body with an even older lens (60 mm AF MicroNikkor 1:2.8) and SB-21 Speedlight flash. However, one of the web's best photographers of arthropods, Myrmecos, has started a weekly series called Thrifty Thursdays on using under $500 equipment to take interesting photos of insects. This has made me feel that I should be doing a better job and this is my first attempt to deal with the cluttered background problem highlighted in the linked post. Below is what I think is a less successful effort, but for some reason I like the clutter in the upper right - makes the fly seem to be seeking shelter in the pansy from the messiness of the world.
Oh well, it's down to a drizzle for the moment. Time to climb the ladder and clear the gutters of those nasty sticky spruce bud caps.

Sunday, June 12, 2011

New to the HBG: The Living & the Dead Psilid

 Another rainy Sunday and another attempt to boost my rate of posting: meet the New to the Home Bug Garden series. Unlike, or rather exactly like, my ‘weekly’ series (Sunday Sawfly, Wednesday Wildflower, Aculeata Agonistes, Bumbling with Bombus, Australian of the Week), New to the HBG will appear only when I have the time, energy, pictures, and story to post. The only real difference is that this series will not be aimed at any particular taxon or cultural view, but at organisms that have recently shown up, been identified, or finally correctly identified.
 The first in this series is a mystery fly that first showed up on 6 June 2009. Well, my wife captured quite a nice picture of the fly on that date anyway. The funny looking head and way the wings bent over the abdomen seemed like they were distinctive enough that we should be able to learn its secret name. We were pretty sure it was an acalyptrate Diptera, but there are far too many flies, even acalypterate ones. Our searching of the web and pestering of Dipterists led to no higher level of knowledge. So, one rainy Sunday, the picture was assigned to the Miscellaneous Diptera folder.
 And that is where it sat until one sunny afternoon last week when I noticed this strange-looking bent-wing fly perching on the leaves of the Juliet Cherry and Red Currant. And that is when I did what we should have done two years ago – if you want to know the name of an insect, you need to collect a specimen and key it out or find a specialist to do it for you (read the caveat in the sidebar: HBG Names & Claims). Specialists are few and far between, but there is an increasing treasure of entomological resources on the web. First and foremost if you live in North America and have a fly, is the Manual of Nearctic Diptera (MND) – an Agriculture and Agri-food Canada Entomological Monograph that is now freely available as a pdf download from the Entomological Society of Canada website (and as reasonably priced print-on-demand volumes here).
 The MND is a tremendous achievement and one wishes that similar volumes were available for each insect order. However, it is highly technical and contains only brief overviews of each family, pictures mostly of bits and pieces, and dichotomous keys to the genus level. To use a dichotomous key, you have to make a series of choices correctly: one mistake and you are buggered. In the case of this fly, I was flummoxed and had to ask for help from our friend Jason. From the pictures, he suggested a likely family: Psilidae (not to be confused with Psyllidae a family of sucking bugs). I had skipped over this couplet in the key because the mystery fly didn’t look like other flies in the families that I knew of, e.g. the Carrot Rust Fly formerly Psila but now Chamaepsila rosae (Fabricius, 1794). Duh! With Jason’s help, the MND, and my dead fly on a pin, I was able to identify the genus: Chyliza Fallén.
 With the genus known and BugGuide, I was able to make a guess at the species, but how would I know it wasn’t another species in the genus? Enter the specialist, Matthias Buck – he said. ‘well, you need to check Melander 1920’. Melander’s paper came out in Psyche, the journal of the Cambridge Entomological Club. A few years ago this is where I would have ground to a halt, because tracking down a paper almost 100 years old in an obscure British bug journal would have been more than the effort was worth. Fortunately, the publishers of Psyche have made this journal both Open Access – anyone with an internet connection can download the papers – and have gone to the trouble of scanning in their entire backlog from 1874 to the most recent issue.
 So, finally we come to the end of our search, the secrete name: Chyliza leguminicola Melander, 1920. Not only did Melander describe this species, but he included what seems to be all that is known about its biology: “... L. P. Rockwood, who has swept this fly from the lupine, Lupinus polyphyllus Lindl., at Forest Grove, Ore., toward the end of April. He has also found puparia attached to the lower part cf this plant during July, from which adults emerged the following March ...”*. And what should be growing under the cherry and currants – lupines! 
 Since psilid flies seem to feed on plants as larvae, I suppose our C. legumnicola might count as a pest. But we long ago stopped planting lupines – they come up on their own and seem to be doing fine even with the fly and the far more annoying Giant Lupine Aphid Macrosiphon albifrons Essig, 1911. I think we will welcome our Bent-winged Lupine Fly to the Home Bug Garden and pin no more.

*Melander, AL (1920) Synopsis of the dipterous family Psilidae. Psyche 27 (5): 91-101.

Saturday, June 4, 2011

Dueling Fabricii: Two Views on Complex Lifecycles

It was 2C this wet and gray Saturday morning, and I guess I could have gotten away with not covering the tomatoes, tomatillos, cukes, etc. last night. It will be cold, wet work uncovering them, so I think I'll leave their rugs on a bit longer and enjoy my breakfast of warm coffee and cold radish. If you think that radishes for breakfast is peculiar, well that's what I thought when I first read about them being a common French breakfast item. I was wrong: crunchy, peppery radishes go well with coffee.
Alas, I don’t grow my own radishes anymore: I have to buy them at the grocery store. The reason is the Striped Flea Beetle Phyllotreta striolata (Fabricius, 1803). You can see one of these above discussing the weather with Black Cherry Aphids Myzus cerasi (Fabricius, 1775) above. Both originated in Eurasia, but have colonized much of the rest of the World. Both were named by the great Danish entomologist and student of Linnaeus, Johan ChristianFabricius. The aphid’s name first appeared in his Systema entomologiæ (1775) and the beetle originally in his Systema eleutheratorum (1801) as Crioceris vittata.
 Fabricius’ ‘System of the Beetles’ (available at Google Books) used Eleutherata for the order of beetles that we now call Coleoptera. I’m not sure why his named didn’t stick – the rules of nomenclature do not apply above the level of superfamily – but he was unlucky with his Crioceris vittata too – the species name was preoccupied and its replacement has wandered through several genera before settling in Phyllotreta. However, Fabricius was able to propose a replacement name in 1803, and so the correct name for the Striped Flea Beetle is Phyllotreta striolata (Fabricius, 1803) (not 1801, as in some references). (The parentheses around the author’s name indicate that the species originally resided in another genus.)
 Thanks to some interesting archeological work excavating a buried privy in Boston, we know that the Striped Flea Beetle has been falling into outhouses in North America at least since 1775 or so (Bain & LeSage 1998). Why are there so many in my backyard? Well, my guess is two-fold: polyphagy and monoculture. The Striped Flea Beetle feeds on a variety of plants in the mustard family (Brassicaceae aka Cruciferae) and so can take advantage of many weedy mustards and the numerous backyard crucifers: radish, turnip, cabbage and similar crops. Also, the Striped Flea Beetle is a major pest in canola in the cooler parts of Alberta (another flea beetle, Phyllotreta cruciferae (Goeze, 1777), is more important further south) (see Dosdall & Mason 2010). Yellow canola fields surround Edmonton in the summer. All of this adds up to a monstrous number of flea beetles.
 Adult flea beetles overwinter in the soil and emerge ravenous in the spring just as the first radish seedlings are germinating. The tiny radish seedlings – just a pair of cotyledons – don’t last long. In contrast, a horseradish that came with the HBG produces large leaves quickly from its perennial taproot and can tolerate a massive amount of damage from its host specialist flea beetle. If I can get the radishes past the cotyledon stage, then I have a hope, but I've failed too many times. I’m trialing turnips this year – planted late and so far not showing much of the typical shot-hole damage. Flea beetles have complex metamorphosis: their grubs live in the soil and feed on roots of the same plants during the summer. The grubs are not considered major pests and for crops like radish and turnip that are soon harvested, they would be trivial. So, if you can beat the adults, you can grow radishes. We will see about turnips.
 Strangely, the Black Cherry Aphid also likes crucifers. You would think that a cherry aphid would stick to cherries, but newly emerged cherry leaves and buds is only their spring food. Although aphids have gradual metamorphosis – their young look more or less like the adults as you can see from the heading picture – they often have a complex life cycle with various winged and apterous forms on two or more host plants. A small dictionary of jargony names been coined for these forms and hosts.
 I’m not a specialist in these bugs, but I’m guessing that the fat black aphids are the fundatrix forms. If so, each developed from a fertilized egg that overwintered on the cherry and are now producing live young parthenogenetically (a long word for without sex). A fundatrix is not going anywhere, nor are her immediate offspring, so they don’t waste any energy producing wings (or males). During the summer, however, winged female aphids develop and disperse away from cherry and on to weedy crucifers or cleavers where they again crank out young without stopping to fool around. In late summer, winged males and females are produced, get it on, and eventually the females leave fertilized eggs on the cherry to spend the winter. This seems to me a complicated way to get from one year to the next, but perhaps all the natural enemies of aphids, the lady bird beetles, lacewings, hoverfly larvae, midge larvae, parasitoid wasps, hunting wasps, gardeners, and assorted diseases, make it worthwhile.

For more information on flea beetles and crucifers see:
Bain, A & LeSage, L (1998) A late seventeenth century occurrence of Phyllotreta striolata (Coleoptera : Chrysomelidae) in North America. Canadian Entomologist 130, 715-719.

Dosdall, Lloyd M. & Mason, Peter G. (2010) Key Pests and Parasitoids of Oilseed Rape or Canola in North America and the Importance of Parasitoids in Integrated Management. pp. 167-213 in Biocontrol-Based Integrated Management of Oilseed Rape Pests.

And for an interesting recent paper on the complex interactions between landscape factors, parasites and predators, ants, and Black Cherry Aphid see:
Stutz, S & Entling, MH (2011) Effects of the landscape context on aphid-ant-predator interactions on cherry trees. Biological Control 57, 37–43.