LOVE IS IN THE AIR. Are you seeing swarms of gnat-like insects hovering over streams, drainage ditches, or poorly drained soils? These are mating swarms of Chironomid midge flies (Family Chironomidae). The cloud-like clusters of these small insects can be hauntingly beautiful as thousands of gossamer wings reflect the early morning or evening sunlight. However, the swarms are notoriously difficult to capture with a camera. The image I've posted this week illustrates the point; the tiny white "smudges" are the midge flies.
Of course, the observer's enchantment with the beauty of the swarms may change once they learn the sordid details of the inner workings within the swarms. A midge fly mating swarm is composed of a throng of lovesick male midge flies. Swarms may be massive numbering in the thousands. Every now and then, an adventurous female midge will try to fly through the aerial mass of zooming, swooping amorous males. The males fly with their legs outstretched in the hope they will snag the female … to get acquainted. Love is in the air!
Chironomid midge flies are not "biting midges"; they lack the necessary biting equipment. In fact, they are considered "beneficial" owing to their status as "decomposers" in aquatic ecosystems and because they serve as an important food item at the base of aquatic food chains. While their swarms may re-appear in the same locations for several days, they are usually just a nuisance to joggers and bicyclists passing through. However, large numbers of mating swarms have been known to present a traffic hazard because of smashed midge bodies on windshields. Of course, some probably died with a smile on their midge faces!
FROM MINUTE TO MASSIVE. Crane flies (Tipula spp.) are another type of fly that's currently on-the-wing; however, these massive flies are much easier to spot (and photograph!) compared to midge flies. Crane flies look like giant, mutant mosquitoes; a startling image outside of a sci-fi movie. Fortunately, these flies also do not possess mosquito-like piercing-sucking mouthparts, so they do not bite. However, large numbers of crane flies flittering above lawns can be a real nuisance, particularly when they find their way into homes.
The larvae of most species of crane flies feed on decaying organic matter in the soil, and they especially appreciate areas that are continuously moist. The larvae of crane flies that feed beneath turfgrass are called "leatherjackets" because of their tough, leathery exoskeleton. Like the adults, these legless maggots occasionally appear en masse spilling onto driveways or sidewalks. Such a dramatic appearance may signal that the lawn has a thatch problem since the larvae are particularly fond of decaying thatch. However, the species found in
LADY BEETLE CURIOSITY. Most people think lady beetles are meat-eaters. In fact, the vast majority of lady beetle species are predators and they will chow-down on any insect or mite that they can get their mandibles around. I've included an image of one of the types of lady beetle larvae that looks like a miniature alligator; it's "hunting" the aphids in the picture. When you look at the image, think of a lion hunting wildebeests grazing on the Serengeti Plains!
However, there is one species of lady beetle that eschews meat for a fungal diet; they are grazers. As its common name indicates, the "Powdery Mildew Eater" (Psyllobora vigintimaculata) makes a living eating powdery mildew fungi. Indeed, research has shown that the tiny beetles will starve to death rather than munching on common lady beetle table fare such as armored scale nymphs or spider mites. The beetles have specialized mandibles armed with rake-like "teeth" that are used to snarf fungal conidia and spores. If you look closely at my picture of an adult beetle, you'll see missing powdery mildew where the beetle has grazed upon the fungus.
Both the larvae and adults feed on powdery mildew and they are very small; adult beetles measure less than 1/8" long. To find them, you must look closely at plant leaves covered in powdery mildew. The brownish-black spots on the beetle are an identifying feature; "vigintimaculata" is Latin for "twenty-spotted." Unfortunately, research has shown that the beetles have a limited impact on their fungal larder; the powdery mildews reproduce faster than the beetles can feed. Regardless, the lady beetle - powdery mildew relationship is fascinating nature story about how the diversity of insects can challenge our preconceived notions.
AILANTHUS ARCHENEMY. Tree of Heaven (Ailanthus altissima) was first brought from China to the U.S. in 1784. The reviews were positive for over a century; this tough tree seemed to be able to grow anywhere. Betty Smith, in her 1943 book, "A Tree Grows in Brooklyn" used the tree as a metaphor for overcoming difficult trials. However, in recent years, the seemingly unstoppable nature of this tree has positioned it at the top of the list of noxious non-native invasive plants; Tree of Heaven has become Tree of ..., well, you know where.
Aside from the expansive ability for this tree to grow under the most difficult conditions, it also lacks natural enemies; just take a whiff of its sap and you'll understand why almost nothing likes to eat this tree's leaflets. Nothing except for Ailanthus webworm (Atteva aurea)! The caterpillars of this ermine moth (Family Yponomeutidae) feed exclusively on Tree of Heaven. The caterpillars consume leaflets enveloped by their webbing and the silk nests can include several hungry caterpillars. The onslaught continues through multiple generations of caterpillars per year with the caterpillars capable of defoliating their odoriferous namesake host. Unfortunately, feeding by this webworm has yet to halt the spread of tree of heaven, although hope springs eternal since this is one of only a few insects known to infest this encroaching non-native interloper.
RUPTURED MILKWEED PODS. I was hiking around Glenwood Gardens on Thursday in search of interesting subjects to photograph (= insects!), and I observed something that I had never noticed before; maybe I had never taken the time to notice. The seed pods on common milkweed were rupturing to release their fluffy, white consignments. At first, there were just a few; then a few more. Eventually, every seed pod had ruptured. I had never noticed the synchrony before and sunlight slanting through the fields highlighted puffs of white here and there. It was a beautiful display and lovely promise that milkweed will reappear next season, along with Monarchs.
MANTIDS, MANTIDS EVERYWHERE! This is the time of the year when it seems that praying mantids are everywhere! Actually, the numbers haven't increased, only the size of the mantids. When mantids hatch from eggs, the "nymphs" are very small and hard to spot as they skitter about on the foliage of plants. The immature mantids gradually become larger with each molt until they finally molt into adults. That's what is happening right now, and the large adults are simply easier to see compared to the smaller nymphs.
All mantids are predators and their meat-eating life style is personified by their specialized raptorial forelegs. Their common name comes from the position they hold their front legs while at rest; they look like they are praying. Of course, once a mantid locates its victim, it's their prey who should be praying! Few victims elude death once they've felt the hug of a mantid. This includes male mantids; the females of some species are notorious for their cannibalistic behavior towards their mates. The femme fatale mantid may consume an amorous male right after mating or shortly after ... gives a different meaning to the saying "hugs and kisses."
Mantids are often highly touted as biological control agents; however, there are usually not enough of them in one spot (they're very territorial) to keep damaging insect populations in check. Additionally, mantids do not discriminate between pestiferous and beneficial insects. Mantids of all species are plentiful and there are no endangered species nor are there species that are protected by state or federal laws.