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.


  1. Nice collection of wasp photos, and you're really becoming quite deft with that point and shoot!

  2. Hmm, yes, this point-and-shooter is getting better at documenting medium to large insects, but the colours are definitely not as crisp as those from Mrs HBG's Nikon and the backgrounds more cluttered and distracting.