Microcosmos 3 - Proliferation in the Quarry Corner

Gaining a glimpse of Microcosmos is a matter of descending through layers of life. The first step is getting to ground level and looking face to face at organic realms that seem as complex in miniature as our familiar landscapes, minus civilization. It is easy to suppose that if further descent were possible we would see nano-worlds populated by bizarre creatures systematically going about the business of their lives. Somewhere, while scaling down to viruses on their home turf, we might pass beyond the frontier of familiarity.

An ant tending aphids

Kneeling in the Quarry Corner I noticed miniscule green grains on the purplish stem of a wildflower Bidens vulgata (Tall beggar-ticks). I zeroed in with help of the close-up lens. Plump, capricorn-looking creatures were lined up cafeteria style helping themselves to the vital juices of the plant. Black ants stepped carefully among them. Other tiny things wandered through the picture.

An ant ingesting plant secretions

One of the ants lapped secretions at the base of a flower. Despite the various plundering the plant seemed to be thriving, probably aided by replacement fluids from the moist growing location.  I wondered if there might be symbiotic bargains at play as with the pollinating-for-foraging exchange I've observed between ants and peonies.

Aphid stages

The still photographs seemed to show aphids at different developmental stages and the dramatic approach of larger black, winged individuals. Through the BugGuide website I sent these photographs to entomologist Natalie Hernandez who monitors aphid incursions for the USDA in Texas. She responded with some illuminating comments on mutualism in the Microcosm. 

Aphid colonies can have a lot going on all at once. These look like Aphis coreopsidis, Tupelo - Blackjack Aphid. They're often attended by ants in the genus Lasius, and the one you photographed does look like it could be Lasius....The ants farm and herd the aphids like cows, except they milk them for honeydew. Since aphids are phloem feeders they've developed a filtration system in their digestive tract to help them get rid of all the water, sugars, and amino acids they ingest, so that produces honeydew. It's very sticky and sooty mold can grow out of control on it. The ants will consume the honeydew, which helps keep sooty mold in check, and protect the aphids from predators.

Aphids shedding their skin

This picture shows 2 alatoid nymphs (will become adults with wings), an alate (winged) adult, and that specimen with the wrinkled wings over on the right is a teneral (newly molted) alate adult, probably just came out of that exuviae on the midrib of the leaf. The darker alatoid nymph looks pharate, meaning it's about to molt. Right before insects molt their old skin separates from the new skin. So often when I slide mount immature aphids it looks like there is an aphid inside an aphid because it was about to molt. It's pretty cool. 

The white things are exuviae, shed skins. I think the white filaments are hairs of the plant, which can apparently be variable in its hairiness. They're supposed to be a defense mechanism to deter herbivores, but aphids have gotten around that hurdle. 

An aphid predator

The orange thing is in fact an aphid predator, a fly larva in the family Cecidomyiidae.... You'll frequently see the larvae of Syrphidae in colonies as well, and sometimes Chamaemyiidae.

I followed the thread into a Wikipedia article on Aphids. "The small, bright orange, slug-like larvae inject a toxin into aphids' leg joints to paralyze them and then suck out the aphid body contents through a hole bitten in the thorax. Larvae can consume aphids much larger than themselves and may kill many more aphids than they eat when aphid populations are high." It's no wonder these flies are used as biological pest controls, in mutualism with human agriculturists.

Ants swarming

One day in September a large congregation of ants milled around beside a fissure in the granite ledge where they lived. Wikipedia research revealed that winged ants leave colonies to form mating swarms, typically in early spring and late summer. By the next day only the quiet, methodical patrols of wingless ants remained visible in the Quarry Corner. Apparently these were sterile females responsible for doing the manual work like tending to the immature larvae, foraging for food, and maintaining the nest. Winged males lead a short and hopefully ecstatic life. According to the Wikipedia article on Ants, the males are "produced only at certain times of the season from unfertilized eggs, and their sole purpose is to mate....Male ants die shortly after mating, usually within a couple of weeks." 

Clearly in the aphid and ant orders of insects success in life is measured in proliferation of the colony rather than individual longevity.