Lupine Bug (Family Alydidae)

Greetings, BugFans,

Isn’t this a lovely little bug! It’s a Lupine bug with the fabulous, 10-syllable scientific name Megalotomus quinquespinosus, one of those “common” insects that has mostly eluded the BugLady.

Lupin Bugs

Lubine bugs are in the bug order Hemiptera and in the Broad-headed bug family Alydidae, a family that is famous not only for their broad heads but for being stinkier than the distantly-related stinkbugs (family Pentatomidae) (more about that later). Broad-headed bugs somewhat resemble leaf-footed bugs and stilt bugs; they are broad-headed, bug-eyed, brownish, long-legged and slim. A bright orangeish spot hidden on the dorsal (top) side of the abdomen is revealed when they spread their wings. Lupine bugs lean toward the rusty end of the brown spectrum, and they have pale legs and dark-tipped antennae and five to six spines on the hind femur.

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The LB is the only Megalotomus in North America, though Eurasia hosts another seven genus members. The species can be found near the edges of woodlands across the continent except (sorry, BugFans Tom and Joe) in the Deep South. The BugLady photographed these not far from where the prairie meets the trees. LBs feed on members of the Pea family (including soybeans), with a little sumac thrown in for spice, inserting their proboscis into the developing seeds and sucking out the liquids therein. According to research by Abell and Tracey, drilling a hole in the seed coat causes the seed to break dormancy and germinate early, and because the LB has robbed the seed of some of its nutrients, the resulting plant is less likely to thrive. It is not considered a pest species at this time, but stay tuned.

Nymphs of some Alydidae are ant mimics, see the (Broad-headed Bug nymph). A few general sources quoted each other, reporting that LB nymphs may live in ant nests, but the BugLady couldn’t find anything specific about that on the web. Ant mimicry (myrmecomorphy—imitating the shape of an ant) allows its practitioner to be a wolf in sheep’s clothing and prey on ants (some spiders do this) or, since ants tend to be distasteful and to deliver a memorable bite/sting/both to prospective predators, to cash in on predators’ avoidance of them. If you’re keeping track of categories of mimicry, this is kind of protective mimicry is called Batesian. Non-ants that live in ant hills are called myrmecophiles (ant lovers). As the ant-hill-dwelling Blue/Azure butterfly caterpillars demonstrate (like Persephone, they spend only part of their time below the ground), myrmecophiles are not necessarily myrmecomorphs. Alydid nymphs even walk and twitch their long antennae like ants, and one Alydid nymph changes color as it grows, mimicking several species of ants by the time it reaches adulthood.

Caterpillars of the endangered Karner Blue butterfly feed on lupine and are tended by ants. During a research project on lupine, Michaels and Mitchell suggested that people who manage land to encourage the butterfly may glance at the LB nymphs, mistake them for ants, and believe that their land is caterpillar-ready when instead, the LB nymphs are threatening the next year’s crop of caterpillar food.

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LBs have two Special Powers. First, both males and females are equipped with sound-making equipment—a stridulatum (rough area) and a plectrum (guitar pick). Like grasshoppers, they rub a spot on their forewing against a spot on their hind leg. Apparently, LBs gather in crowds from time to time, like a speed-dating event, and these aggregations may also include several other species of broad-headed bugs. The noise-making is thought to be a Call-to-Meeting, and it may help the bugs determine individuals of their own species.

And then there’s that body odor, which is described as smelling like a severe case of halitosis. The brightly-colored patch hidden on the insect’s back is probably a warning signal that it flashes when disturbed. LB nymphs and adults deploy a defensive odor (alarm pheromone) as droplets, not as aerosol. As in some other insects with that capability, the outlet of the scent glands on nymphs is located on the dorsal surface of the abdomen, but since that area is covered by wings in an adult, the openings of the scent glands must move to the ventral (lower) surface of the thorax in the adult. An adult’s ability to wage chemical warfare lessens as it ages (the BugLady can hear what you’re thinking); it takes 24 to 36 hours to replace a scent droplet.

The BugLady