While the eyes of most grub-like insects detect little more than light and dark, those of tiger beetle larvae are densely packed with photoreceptors that permit detailed focusing and depth perception for detecting whether potential prey has ventured close enough to their burrow (Pearson et al. The life of a tiger beetle larva is a life of waiting – unlike the adults who run down their prey, the larvae sit in their burrows and wait for prey to come to within lunge’s reach. Close examination of the hump reveals an intricate pattern of forward-facing hooks and spines that function in anchoring the larva against the side of its burrow to prevent struggling prey from dislodging it. The remainder of the body – long, narrow, and cylindrical – hangs from the head at a 90° angle down into the burrow and is unremarkably grub-like, save for a curious hump on the dorsal side of the 5th abdominal segment. The top of the head is flattened to lie flush with the surrounding soil as the larva sits at the top of its burrow, and huge, powerful mandibular muscles fill the cranial cavity. ![]() ![]() The large, heavily sclerotized head bears two long, sickle-shaped, upward-pointing mandibles and up to three pair of highly-acute eyes whose arrangement on each side conveys the image of a “face” with congenital birth defects. It was a good jab – I had blocked its retreat without injuring it, and a quick flip of the knife popped out the soil plug and exposed the startled larva, flipping vigorously in a vain attempt to escape before settling down amidst its unfamiliar, exposed surroundings.įor those of you who have never seen a tiger beetle larva, they are among the most other-wordly creatures one can imagine. I positioned the knife and waited – crouched under the baking Florida sun, until when it did re-appear I plunged the knife into the soil with authority. No matter, I knew it was in there now and that it would likely reappear if I could muster the patience. I slowly got out my knife and moved to place the tip on the soil about 1″ from the burrow at a 45° angle for an attempted tunnel block (Pearson and Vogler 2001), but it spooked and dropped back down into its burrow before I could get then knife in place. Fortunately my wait was short, as within a few minutes I saw one re-appear at the top its burrow. Waiting for tiger beetle larvae to appear is a crap shoot – maybe they’re active, and maybe they’re not, and crouching in the stifling summer air of a coastal marsh in Florida is not an easy thing to do for very long. I tried fishing (Pearson and Vogler 2001) a few holes with a grass blade but didn’t get any bites, so I decided to watch for awhile and see if any of the larvae, believing the danger of my approach had passed, would reappear at the tops of their burrows. The size of the burrows (~5mm dia) suggested they were inhabited by 3rd instar larvae (the final instar before pupation), in which case it may be possible to rear a few to adulthood – if I could get at them. I then reasoned, however, that more likely they represented another species whose adults are active later in the season – perhaps one of the so-called “spring/fall” species whose larvae typically reach maturity during the heat of summer. There were a number of burrows clustered on the small bit of high, dry ground, and my first thought was that their inhabitants represented the same (what I thought was a single) species that I had encountered so commonly that day as adults. ![]() ![]() Larval burrows, especially larger ones such as these were, are unmistakeable – almost perfectly circular (slightly cut out on one edge) and smoothly beveled around the perimeter. As I approached I saw something I hadn’t yet seen that day – tiger beetle larval burrows. I had spent close to two hours under the August sun observing and photographing the beetles before I decided that I had given the preserve a thorough enough look.Īs I was heading back, I noticed a little bit of high ground alongside a red mangrove thicket and went over to give it a look. hamata lacerata (Gulf Beach Tiger Beetle). The specimens I collected and photographs I took would later reveal that two co-occurring and closely related species were present: Ellipsoptera marginata (Margined Tiger Beetle) and E. Despite its small size and urban surroundings, the narrow strip of coastal scrub and saltwater marsh along the intracoastal waterway behind my sister-in-law’s condominium boasted a robust population of what I took to be a single tiger beetle species. My first experience looking for tiger beetles in Florida had gone well.
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