Friday, July 1, 2016

Beneficial Insects Dress Like the Costumed Cops of Disneyland
To Protect the Roses While Feeding Their Young

Tachinid Fly


Long ago Team Jackson went to Disneyland. We got to see our favorite characters in giant costumes.

As many people know, the underground passages allow the characters to emerge seemingly like magic.

We heard that many of them are actually involved in security, so they keep an eye on everything in their casual, friendly, appealing costumes.

Once I read about Tachinid Flies, I wondered when I would see them. Unbidden, they came to our garden to do their work. I see them all over the garden.

Tachinid flies FAMILY Tachinidae 
NORTH AMERICAN SPECIES 1300+ 

You may not think a fly to be all that interesting, but I can assure you that this large and diverse family of parasitoids participates in some of the most fascinating interactions in the insect world. Tachinids are among my favorite of all natural enemies, and it surely isn’t for their good looks. It is instead for the intriguing lives of these humble-looking creatures. 

Tachinid flies are highly variable in their physical appearance. Measuring primarily 0.12–0.55 inch (3–14 mm), with a few larger and smaller species, they most resemble plain old houseflies. Tachinids can be gray, black, or darkly striped and have distinctive hairy bristles protruding from their abdomens. Some species have four black longitudinal stripes on their thorax (the part of the body between the head and the abdomen). The presence of only three stripes indicates it is instead a flesh fly—you know, the ones that eat carrion and poop. A few species of tachinids are bright orange or even metallic blue or green, but most are just plain drab. If you really want to discern them from a housefly, look for a pronounced subscutellum, best described as a distinct rounded ridge on their posterior. I, for one, am not all that interested in examining a fly’s posterior, so I rely more on the presence of the abdominal bristles for identification.

Tachinid flies, parasitoids that resemble bristly houseflies, feed on pollen, nectar, and honeydew and are highly variable in appearance and size. Most are dark in color, though a few brightly colored species exist. 

Adult tachinids feed on pollen, nectar, and honeydew and are important pollinators. They are very active fliers and are often seen alighting on flowers, fences, rocks, and people. All species of tachinids are parasitoids that use various insects as larval hosts. Most species use caterpillars (cabbage loopers, corn borers, gypsy moths, cutworms, fall armyworms, coddling moth larvae, leaf rollers, bollworms, and many, many others) as hosts while other species parasitize adult and larval beetles, and even various true bugs and sawfly larvae. Tachinids can be generalists that use assorted species as larval hosts or specialists relying on only one species to feed their developing young. 

Egg-laying techniques are variable and incredibly intriguing. Some species deposit one or more eggs onto the host insect’s exterior or (rarely) inject the egg inside the host. Others lay an egg near a leaf-munching pest; when the egg hatches a few hours later, it is ingested right along with the plant tissue. Still other species deposit live larvae into the host. For those species that lay eggs on their hosts externally, the 0.04 inch (1 mm) white elongated eggs are easy to spot, particularly when clinging to caterpillars and host insects like Japanese beetles, squash bugs, and stink bugs. Once hatched, the larval maggot begins to consume the host’s internal tissues and completes its feeding in four to fourteen days. In most cases, the larva then emerges from the dying host and pupates independently.

Walliser, Jessica. Attracting Beneficial Bugs to Your Garden: A Natural Approach to Pest Control (Kindle Locations 846-859). Timber Press. Kindle Edition. 

When I see flies in the garden, they are Tachinids, either gathering pollen as adults or laying eggs that will hatch into maggots that live on aphids.

The first bloom of roses provided food for the adults and a pleasant nursery for their young. Just like last year, the white and Peace roses were drained by aphids. I did not panic. No toxic sprays were used. Instead, I waited for beneficial creatures to come to the rescue.

This miniature bee is just fooling -
he is a Flower Fly or Hover Fly - Syrphid.

Dressed as

  • Spiders, 
  • Tiny wasps (Ichneumons), 
  • Miniature bees (Flower Flies),  and 
  • Houseflies (Tachinids) -

these beneficial creatures turned the rose garden into a food court, The aphids needed food, but they only created a banquet for the beneficial creatures, which multiplied to feed on the feeders. Not one, but many beneficials came to the rescue. All the roses can bloom for the rest of the summer without much damage at all. If a few blooms are damaged, it is only to keep the food cycle going.