I had been slowly making my way down the rail tracks for about half an hour before I spotted the first one of these – a Six-spotted Tiger Beetle. Metallic green and vibrantly flashy in the morning sunshine, I’m surprised I’d missed them to that point, since, even though I was somewhat distracted by the birds in the trees lining the rail bed, I had also been paying some attention to the ground, looking specifically for flowers with insects on them. The tiger beetle wasn’t at the flowers, admittedly, but it would be very hard to miss such a strikingly bright insect.
These are my favourite of the beetles. Appearance-wise, it’s easy to see why they appeal. There are many beetles, though, that are flashy, iridescent, eye-catching. The scarabs are especially known for it, as are the metallic wood borers. Many scarabs also have interesting horns or such, and long-horned beetles have outlandishly long antennae. We have some of all of these around here, but it’s the tiger that remains my favourite.
Part of it is probably just that they’re quite common, a familiar beetle of early summer, and yet I’m always pleased to spot them. They tend to frequent trails and other open areas in or adjacent to deciduous woods. I tend to associate them with successional areas, spots with many young trees and shrubs, although I don’t know if this is because it’s a favoured habitat, or just simply where I happen to be more often. I’ve never seen one down at the bird research station, nor at my parents’, but they’re fairly abundant at the station’s summer banding research site, and were along the rails here, too. They’re not that big, at not much more than 13 mm (1/2″), but still large enough to catch your eye.
The adults of this species give the critters both their common and scientific names (Cicindela sexguttata). On most individuals, they have six yellowish-white spots that rim the outside of the elytra (wing covers). The number of spots on individuals can be variable, ranging from none or two up to six or eight. In the case of this one, it has an extra two spots in the inner area of the elytra, to form eight spots total.
I think part of it is also their personality. Tiger beetles obviously don’t take their name because of any physical resemblance to the mammal of the same name, since I have yet to see a tiger that’s metallic green. Instead, their name reflects their personality, and their hunting behaviour. These beetles are predaceous, preying on other small invertebrates. They especially like ants and spiders, but anything small enough to be consumed can become prey. They move with lightning speed, using this to their advantage to snatch prey before it knows what’s hit it (much like jumping spiders do; obviously camouflage is not an effective tactic with these guys).
Maybe their fangs come in to the name, too. Look at the size of those jagged-toothed mandibles relative to the beetle’s head. These massive jaws are characteristic of the group, and are used in subduing and ingesting prey items. They also have very large eyes, which are important for spotting and tracking prey as it moves. It has excellent vision, and they’re very hard to sneak up on. The one downside to this macro lens is that it’s shortened my focal distance, so now I need to be within 6 inches of the subject to get the true macro 1:1 magnification. You get fabulous photos, but only if you can get close enough to take them. Patience is definitely required; either that, or setting your camera up pointed at a flower and waiting for the bug to come to you. Which won’t work so well for these guys.
While I watched this guy, trying to get close enough to run off a series of good, sharp-focused shots, he pounce on and ate something. It happened so quickly, and I was sufficiently distracted, that I didn’t see what it was he ate. It appeared to maybe be a small spider. Whatever it was, it had many long, thin appendages sticking out of the tiger beetle’s mouth as he chewed on it.
There are 14 species of tiger beetles in Ontario, of which the Six-spotted is probably the most common. Certainly it’s one of the most generalistic, inhabiting a wide range of habitats and ranging across a broader portion of the continent. It’s found from New England, west through southern Canada to North Dakota, and south to central Texas and Florida. Sand dunes, gravel pits and beaches are among the best places to look for some of the other species, but rocky alvars and exposed rock or dirt in meadows or fields are also good spots. Not all of them are such flashy colours; many are dull browns and patterned to blend in with the ground, making them harder to spot (and also more easily overlooked, for someone who’s not actively looking).
This guy seemed to be hungry. With his second pounce, he grabbed what appeared to be a bit of dead leaf. Eventually he dropped it, losing interest, or perhaps distracted by something else. Both adults and larvae are predaceous. Adult females mate in the spring and lay each egg in a short burrow in the ground, where, sometime in late June or July, it hatches into a worm-like grub with fangs. It digs itself a longer, vertical tunnel, which it lives in the rest of the summer. It eats similar prey to the adults, lying in wait within its tunnel for some unsuspecting insect to wander by. It spends its first winter in its tunnel as a larva, awakening in the spring once the ground warms up. Later that second summer, in August or September, it pupates within its tunnel. Although it becomes an adult that fall, it doesn’t actually emerge from its tunnel until the following spring, when it will mate and start the next generation’s 2-year cycle.
I tend to think of these guys as species of high summer, but the websites I referenced seemed to indicate they are more of a mid- to late spring species. None of them gave the lifespan of adults, but the Ontario website indicates a few can be found into fall. Some adult insects lack mouthparts to feed as an adult and die shortly after emerging and mating, but this is obviously not the case for these beetles. I’ll look forward to watching them this spring and summer as I do my surveys there and at the station’s summer site.