Sunday, October 30, 2011

A long reach: Daddy-long-legs aka Harvestmen

Meet Phalangium opilio Linnaeus, 1758
I've been trying to decide if a Daddy-long-legs would make a good Halloween costume, but I think the 'face' would be too strange to be scary and the legs far too long and cumbersome for walking around.  Even capturing the legs in a photo of the body can be a problem.
Phalangium opilio has only one generation a year in the Home Bug Garden. At the moment they occur only as eggs hidden in the soil by the ovipositor of the female. In the spring, usually in late May, the tiny young can be seen scurrying around the garden, but one has to look closely to see them. By the end of June they are large enough to be noticed as they nonchalantly wander around feeding on small live insects, dead insects, bits of rotting fruit, and probably from pollen in the flowers they frequent. By the harvest season, they seem to be everywhere, and hence, their other common name.
Daddy-long-legs live up to their name - a front leg, about 6x the length of the body, reaches into the upper left corner of the picture.
Alberta is home to a half dozen or more 'native' species of Opiliones, the order of arachnids to which the Daddy-long-legs belongs, but our species isn't one of them. Phalangium opilio apparently came from Eurasian with the more recent waves of Eurasian colonists and, like the sowbugs in last week's post, is found mostly around people in cities and suburbs. We quite like ours, and can't see any reason not to. They don't bite, they don't bother, and they don't do any damage to the garden. Besides, I was told as a child that if you are lost, catch one, and knock off a leg, it will twitch in the direction of home.
Alien but inoffensive
Several other arthropods are called Daddy-long-legs including flies in the family Tipulidae and spiders in the family Pholcidae such as Pholcus phalangioides  Fuesslin, 1775. These arthropods are easy to tell apart since the spider has a spider's waist and the crane fly has a pair of wings, unlike Phalangium opilio, which has neither waist nor wings at all. We have lots of craneflies in Alberta, but I have yet to see a daddy-long-legs spider. Although this is another of our arthropod synanthropes that have been moved around the world by people, they haven't made it to our basement.
Another kind of daddy-long-legs: Crane Fly (Tipulidae)
A bit of sun, an absence of wind, and the promise (but not yet the reality) of double digit temperatures (in Celsius) this Sunday, perhaps the last positive double digits we will see until April. Good reasons to get out into the garden, or what is left of it. Alas, it is a sad day for the birds - we have taken advantage of the relative warmth to turn off the bubbler, break the crust of ice, and pull the pump and filter out of the pond. The birds will continue to return for a couple of days, peering down the fountain hole, but no more water will be forthcoming until next spring.

Saturday, October 22, 2011

Porcellio spinicornis Say: The Spine-horned Little Pigbug that didn’t belong

A cluster of Edmontonian Sowbugs aka Woodlice when they aren't in a yard

Swans were winging their way overhead this morning, but the chill and the wind have kept what winged-insects are still about well hidden. It’s that time of the year for raking leaves, cutting down frost withered vines, composting rotting green tomatoes, and emptying pots of browned flowers. Moving pots, though, does give one the chance to observe some of the less obtrusive arthropods that skulk under them and scatter to any convenient crevice when disturbed. Among the skittering is one I have been meaning to write about for awhile, but never had the time to sit down and work out its proper name.
A freshly moulted Sowbug in an Edmonton backyard
What I did know was that the small, flat arthropods that were so common underneath things in my backyard were members of the crustacean order Isopoda (they have 7 pairs of legs). In Australia, I would have called these animals 'slaters', but when I was a kid in another land, I called them ‘so-bugs’. I got the common name, sowbugs, from a book and assumed it had something to do with them being scattered across the ground like sown grain. When you turned over a rock or board or moved a pot, they did sort of look like scattering grains, so the name seemed to make sense. But much to my embarrassment, as a young entomology student I learned that everyone else in North America called them ‘saughbugs’ after  fancied resemblance to female pigs! Some sowbugs can roll into a ball (conglobation) when disturbed, and these are called pillbugs for a reason that was obvious even to me.
Conglobated Pillbug (probably Armadillidium vulgare) from BC
Well, whatever you call them, sowbugs are one of the more successful lineages of land animals. We usually think of crustaceans (crabs, lobsters, crayfish, shrimp, prawns, and the like) as being inhabitants of the oceans, but most of the 3600 described species of the suborder Oniscidea are fully terrestrial.  An exception are members of the family Ligiidae that live an amphibious existence along the coast (see Ted MacRae’s great post). The earliest known fully terrestrial isopods are Eocene fossils from after the great extinction event that removed the dinosaurs inter alia at the end of the Cretaceous Period. Perhaps one or more ancestral amphibious sowbug found life on land easy in the brave new Eocene world, but in any case, their descendants have colonized most of the landmasses on earth (Antarctica and a few small islands excepted). Mostly they all do the same thing – eat decomposing plant  matter and so are ‘good bugs’, at least to any gardener that likes a healthy garden.
Sowbug lurking in a crevice - something they do very well
Until about 9-10,000 years ago, Alberta was pretty much free of any animal life, let alone sowbugs. Any that once lived here would have been ground to dust by the glaciers and this state of affairs seems to have held until recently. My wife, who grew up in Edmonton and enjoyed turning over rocks to see what lived underneath, claims there were no sowbugs here when she was a child. Our friend John Acorn, a dedicated Albertan naturalist, supports her claim. Jass & Klausmeier (2000) list no records, whatsoever, of terrestrial isopods from Alberta. So, what is this slater living in my backyard?
Antennal spines (arrows), black head, dark midline stripe, yellow spots, arrangement of lungs, and other characters support Porcellio spinicornis Say, 1818
Answering that question is what took so much time; however, thanks to an excellent key by Stephen Hopkin (1991), the invaluable BugGuide, the University of Alberta library, and a certain terrier-like attitude to unnamed bugs by both Mr & Mrs HBG, we now have an answer. Back in 1818, Thomas Say, the great American naturalist, conchologist, entomologist, and nascent explorer, published a paper in the Journal of the Academy of Natural Science (Philadelphia) on new species of Crustacea he had discovered in the United States. Among these hard shellfish was one whose ancestors left the oceans long ago and had spread far and wide on land: Porcellio spinicornis Say, 1818. Apparently, Say was impressed by the dorsal ridges on the second and third antennal segments that ended in stout spines (hence spini [L. spine] corn- [L. horn, or in this case, antenna]) and no doubt the attractive colours in the living animals. Presumably, Pierre André Latreille, who in 1804 named the genus with the Latin for a small pig was channeling the sowbug meme. However, this Spine-horned Little Pigbug should not be confused with another widely distributed sowbug, the Common Woodlouse Oniscus asellus L., 1758, a species that I have yet to see in Alberta.
Common Woodlouse from BC
Say appears to be wrong about the origin of his woodlouse. Today Porcellio spinicornis Say is considered one of about three dozen species of terrestrial isopods that have been introduced into the Americas from the ‘Old World’. This must have happened very early on, but now this species can be found in much of North America including Canada (although not officially in Alberta). Some pest control operators like sowbugs, because fussy homeowners find them distressing and are willing to spend money to have them sprayed into oblivion. I don’t see why. Although they do scurry about and hide under pots and the like, they appear to eat nothing except plant matter that has died and been overgrown with fungi and bacteria. This seems fine if they keep to cities and suburbia and so far, that is what they seem to do.


Hopkin SP. 1991. A key to the woodlice of Britain and Ireland. Field Studies Council AIDGAP Guides 204

Jass J & B Klausmeier. 2000. Endemics and immigrants: North American terrestrial isopods (Isopoda, Oniscidea) north of Mexico. Crustaceana 73 (7): 771-799.

Leistikow A & Wägele JW 1999. Checklist of the terrestrial isopods of the new world. (Crustacea, Isopoda, Oniscidea). Revta bras. Zool. 16 (1): 1 - 72,1 999

Lindroth CH. 1957. The Faunal connections between Europe and North America. Biodiversity Heritage Library

McQueen DJ. 1976. Porcellio spinicornis Say (Isopoda) demography. II. A comparison between field and laboratory data. Can. J. Zool. 54: 825-842.

McQueen DJ & JS Carnio. 1974. A laboratory study of the effects of some climatic factors on the demography of the terrestrial isopod Porcellio spinicornis Say. Can. J . Zool. 52: 599-611.

Say, T., 1818. An account of the Crustacea of the United States. Journal of the Academy of Natural Science Philadelphia, 1: 235-253, 313-319, 374-401, 423-458.

Schmalfuss H. (2003): World catalog of terrestrial isopods (Isopoda: Oniscidea). Stuttgarter Beiträge zur Naturkunde, Serie A, Nr. 654: 341 pp.

Schmidt C. 2008. Phylogeny of the Terrestrial Isopoda (Oniscidea): a Review. Arthropod Systematics & Phylogeny 66(2): 191-226.

Friday, October 14, 2011

Wine, Bacon, and Beetles

A beetle that appreciates wine - the Picnic Beetle
Autumn has certainly settled in and as the leaves colour and fall, the other garden colours also fade away. Gone are the butterflies, yellowjackets, bumble bees, and flower flies. A few flowers still linger in spots sheltered from the frost, but only honeybees visit them. If you search around, there are still plenty of grey flies and midges. A small swarm of Dixella midges were dancing near the pond on a warm evening just last week. But the drabness of winter is clearly drawing neigh.
Glischrochilus fasciatus (Olivier, 1790)
So a colourful beetle is a welcome visitor, even if it seems intent on drowning in one's wine. Glischrochilus fasciatus (Olivier, 1790) has a number of boring common names based on its spots, but my favourite nom de bug is the Picnic Beetle. A member of the Sap Beetle family (Nitidulidae), well known for their fondness for fermenting plant juices, the Picnic Beetle often lives up to its name and pesters those of us that quaff our fermented drinks outdoors. The adult beetles overwinter, so their autumnal draughts are probably the last fun they'll have until the spring.
Dermestes lardarius - aka Bacon or Larder Beetle
Another, less colourful beetle, has also been around, but is not so welcome. Dermestes lardarius was named by Linnaeus himself in 1758 and now occurs around the world in people's homes. The most common common name seems to be the Larder Beetle, but I prefer the Bacon Beetle. Any beetle that likes bacon must have some redeeming qualities. Like the Picnic Beetle, the Bacon Beetle overwinters as an adult. The larvae prefer high protein foods and commonly dine on meat, pet food, and dead insects. I imagine they miss the good old days when hams and bacons were hung near the fireplace, but they seem to do just fine on what they can find now.
Hyssopus officinalis flowers into October

Friday, October 7, 2011

Bumbling with Bombus: I’m a bad, bad, bee

Indiscriminate Cuckoo Bumblebee Queen
September was mostly a dry and sunny month in Edmonton with the Home Bug Garden dipping to freezing only twice and no lower than 1.3 C at the downtown airport. So, garden flowers, even the monkshoods that never quite manage to flower before being killed by frost, and a few of the insects that visit them (especially hover flies) have persisted unusually long this autumn. Outside the heat island of the City, though, we had hard frosts (-4) at the Moose Pasture by mid-September. Frost and dryness put end to most of the flowers and only a few asters were still blooming. Well, wild asters and the coneflower (Echinacea purpurea) we had planted on the edge of our small garden plot.
A usually too late bloomer Aconitum divergens
 We didn’t expect much on our mid-September trip except grasshoppers and dragonflies. So my wife didn’t bring her fancy camera, just the point-and-shoot Canon Powershot SX20 that she uses for landscape photos. That caught us up short, because our coneflower, was hosting a small swarm of bumblebees. Mostly these were queens of the Half-black Bumblebee (Bombus (Pyrobombus) vagans Smith, 1854) stocking up for the winter hibernation and a couple of drones hanging on for dear life. But one of the large black and yellow bees looked a bit different – and so it was, an Indiscriminate Cuckoo Bumblebee Bombus (Psithyrus) insularis (Smith, 1861).
Moose Pasture in mid-September 2011
 When bumblebee queens start their nests in the spring, mostly they just work hard to get their colonies growing. But sometimes a queen who has lost her nest or failed to start one will enter the colony of another and try to kill the resident queen and take over. This is called colony usurpation or queen supercedure. Presumably environmental factors such as spring weather and the availability of nest sites influence how often this happens, but usurpation can be common. As many as 20 dead queens have been found in a single nest (Kearns & Thomson 2001) indicating fierce competition for a site. Often a homeless queen tries to steal the nest of another of her species, but other Bombus species are also fair game. Some time in the distant past, one group of bumblebees gave up on raising their own workers and became obligate social parasites – invading nests, killing queens, and co-opting the resident workers to raise broods of cuckoo queens and drones. Compared to queens of other subgenera of Bombus, cuckoos in the subgenus Psithyrus are more heavily armoured, have larger mandibles, a longer curved sting, a more elaborate venom apparatus, more ovarioles, and lay smaller eggs (Fischer & Sampson 1992). So, Psithyrus species seem very well adapted to their nefarious activities.
Note yellow hairs on head, black on base of abdomen
 Our Bombus (Psithyrus) species has acquired the common name of ‘Indescriminate’ and the data that GA Hobbs gathered in the 1960s supports the name. Hobbs worked at what is now known as the Lethbridge Research Centre and most of his data is from the southern part of the Province. He found that what was then known as Psithyrus insularis was successful in usurping the nests of Bombus (Bombias) nevadensis, Bombus (Thoracobombus) fervidus (as B. (Fervidobombus) californicus), Bombus (Subterraneobombus) appositus, Bombus (Bombus) occidentalis and terricola, and many species of Bombus (Pyrobombus). For Pyrobombus, the most diverse and abundant Bombus in the Edmonton area, Hobbs (1967) found 97/191 (51%) of the nests harboured the social parasite. This seems very high, but is similar to what has been reported for European bumblebees parasitized by another species of Bombus (Psithyrus) (Erler & Lattorff 2010). If you think bumblebees are good, and you worry about their conservation, then this may be a bad, bad, bee.
Bombus (Psithyrus) insularis - Indiscriminate Cuckoo Bee
Craig CH. 1953. Psithyrus insularis (Sm.) in a Nest of Bombus ternarius Say (Hymenoptera : Bombidae). Canadian Entomologist 85: 311-312.
Erler S & Lattorff HMG. 2010. The degree of parasitism of the bumblebee (Bombus terrestris) by cuckoo bumblebees (Bombus (Psithyrus) vestalis). Insectes Sociaux 210: 371-377. 30-100%, 33-50%
Fischer RM & Sampson BJ. 1992. Morphological specializations of the bumble bee social parasite Psithyrus ashtoni (Cresson) (Hymenoptera: Apidae). Canadian Entomologist 124: 69-77.
Hobbs GA. 1965. Ecology of Species of Bombus Latr. (Hymenoptera: Apidae) in Southern Alberta. II. Subgenus Bombias Robt. Canadian Entomologist 97: 120-128.
Hobbs GA. 1966. Ecology of Species of Bombus Latr. (Hymenoptera: Apidae) in Southern Alberta. IV. Subgenus Fervidobombus Skorikov. Canadian Entomologist 98: 33-39.
Hobbs GA. 1966. Ecology of Species of Bombus Latr. (Hymenoptera: Apidae) in Southern Alberta. V. Subgenus Subterraneobombus Vogt. Canadian Entomologist 98: 288-294.
Hobbs GA. 1967. Ecology of Species of Bombus Latr. (Hymenoptera: Apidae) in Southern Alberta. VI. Subgenus Pyrobombus. Canadian Entomologist 99: 1271-1292.
Hobbs GA. 1968. Ecology of Species of Bombus Latr. (Hymenoptera: Apidae) in Southern Alberta. VII. Subgenus Bombus. Canadian Entomologist 100: 156-164.
Kearns CA & Thomson D. 2001. The Natural History of Bumblebees. University of Colorado Press, Boulder.

Sunday, October 2, 2011

Aculeata Agonistes: The Good, the Bad, and the Indifferent

Western Yellowjacket - note folded wings, yellow eye loop, and feeding at nectary
I know I tend to harp on this, but people seem to like to view the world through simple dichotomies. Good and Bad Bugs is one such model. So, to most, mosquitoes are bad bugs, ladybird beetles good bugs. Or if you are of a more pedantic school of entomology, Hemiptera are good bugs and other arthropods are not. Yellowjackets, hornets, and wasps probably tend to fall into most people’s bad bug category because they can sting you and cause pain and possibly death, as in this sad story of a man who bumped into a wasp nest while taking a hike with his 13-year-old daughter in Queensland.
 Wasps in the family Vespidae are those most likely to sting you, but not all vespid wasps are equally quick to use their venom delivery apparatus on something as large as a person. For example, the industrious mud-dauber Ancistrocerus waldenii that I spent some time studying early in the summer never paid much attention to me, even when my point-and-shoot was only a few centimeters above her. You can tell she is a good vespid wasp by the fact she did not sting me and by the way the front wings fold lengthwise when held at rest (in other wasp families, the front wings are typically held flat).
Mud-duber Ancistrocerus waldenii - a good wasp
Other solitary vespids in the HBG go about their lives in an equally oblivious way, doing the things wasps like to do. If I get too close to them, they flee, although sometimes they have too much on their minds to do more than hang around. Mostly, though, we share the yard without a problem.
Ancistrocerus parietum exploring the erotic potentials of dill
On the other hand, worker yellowjackets in the Vespula vulgaris group are bad. They invariably give me a buzz on their way through the yard. The Western Yellowjacket (Vespula pensylvanica) at the top is one of this group – the workers are pushy and aggressive. When I swat at a wasp, I expect it to move on with alacrity – but these wasps respond by buzzing around and getting in my face. This is especially true if I have food or drink with me – they scavenge as well as hunt.
Male Aerial Yellowjacket nectaring at goldenrod
The taste for colas and hambugers of the vulgaris-group species is not shared by other yellowjackets in my yard –those workers spend most of their time hunting insects and males malinger on flowers. I guess that makes them good, unless I bump into their nest.
More black than yellow - Vespula alascensis male (note 7 abdominal segments)
The vulgaris-group gets its name from the Common Yellowjacket Vespula vulgaris. This species used to be common here, but then taxonomists discovered that vulgaris was restricted to Europe (and areas of the world into which it has been introduced such as Australia and New Zealand). Our North American vulgaris-like species is Vespula alascensis – smaller and darker than the Western Yellowjacket, but also annoying. Being newly rediscovered (it was actually described in 1870), V. alascensis lacks a common name (BugGuide gives it none). The ‘More Black than Yellowjacket’ would be descriptive of its looks and the ‘Lesser Annoying Yellowjacket’ would describe its behaviour well enough.
Hi, I have no common name - Vespula alascensis male
One interesting aspect of the HBG the last couple of warm weeks (now replaced by cold, wet) was the number of male yellowjackets. Although the males can’t sting, and so I guess are good, I still sent about two dozen to science heaven. Almost a third were V. alascensis – although none annoyed me. Actually, they were very unobtrusive, other than wanting drinks from around the edge of the pond. They don’t seem to be interested in nectar, wine, or even barbecues. I guess they must have gotten fed enough as youngsters in the nest to last out the autumn.
13-segmented antennae identify a male - scape, pedicel, and 11 flagellomeres
Most of the rest of the males were the Western Yellowjacket (Vespula pensylvanica). This was no surprise – the few annoying yellowjacket workers around this summer were V. pensylvanica. Unlike the workers, these males are entirely innocuous and seem to be mostly interested in landing on lawn or low vegetation and then crawling to the ground. I find this behaviour mysterious, but those I followed around did nothing more exciting than lap up water.
From its yellow eye loop, a Western Yellowjacket (and male)
Two of the males, though, were yet another vulgaris-group species, Vespula germanica, a recent colonist from Europe. Apparently the common name now used is German Yellowjacket – which seems unfair to the Germans and a poor descriptor of a more widely distributed European species. Since the German Yellowjacket is expanding its range in North America, technically it must be an invasive species; and therefore, even the males must be bad.
A doubly bad German Yellowjacket - well, at least the eye loop is absent
As far as I can tell, the German Yellowjackets are no worse that the Western Yellowjacket, but they are hard to tell apart. The best field character is the colour around the eyes:  the yellow around the eyes of germanica is absent at the top of the eyes, but in pensylvanica it is usually present. Usually, but not always, so like most dichotomies, this is a bit more complicated than it should be.
7-spotted Ladybeetle - 6 US states have designated this beetle
their state insect - but it is an invasive species; and therefore, bad.