31 August 2024
After the day gone by night time’s rainbow a “triangle fly” landed on our eating room window and spun its frame slowly like a best. Google Lens known it as genus Rhagoletis, a member of the fruit fly circle of relatives Tephritidae.
There are about 25 species of Rhagoletis local to North The usa, each and every with its personal host fruit. Those that consume the end result we develop commercially, reminiscent of cherries and walnuts, are regarded as agricultural pests.
Since my photograph presentations the trojan horse’s underside, Google Lens picked up at the yellow frame and known it because the walnut husk fly, Rhagoletis completa, although it’ll had been a special species such because the intently comparable Rhagoletis suavis. There are black walnuts in Pittsburgh’s parks so those species are chances.
Right here’s a topside view of Rhagoletis completa.
Grownup feminine Rhagoletis inject their eggs into the host fruit in order that the larvae have one thing to consume once they hatch. Should you open an infested fruit it appears adore it has maggots. Right here’s a walnut husk (sure, it’s a fruit) with R. completa larvae in it.
Possibly that’s why we once in a while see rotting black walnut husks at the flooring.
Rhagoletis are preyed upon through leaping spiders!
Some species mimic leaping spiders. The wing-waving it sounds as if deters the way of leaping spiders, vital predators of the flies. Different species have brightly-patterned our bodies, and would possibly mimic wasps.(3)
“Spider predation has been intense sufficient to mildew the evolution of prey traits: predation through salticids (leaping spiders) has formed the morphology and behaviour of some tephritid flies. Their wing markings resemble the trend of the legs of leaping spiders; the flies additionally wave their wings in a way that looks to imitate the agonistic habits of salticids – making them ‘proverbial sheep in wolf’s clothes’.”(8)
May this local North American leaping spider be a predator of our Rhagoletis flies? Do you spot a resemblance between its angled legs and the trend at the fly’s wings?
The triangle fly has opened a complete new space of inquiry.