Trimorus in the troposphere

This week features two images of Trimorus, a genus of platygastroid wasps that parasitize the eggs of ground beetles (Carabidae). These two species are closely related and belong to a cosmopolitan lineage that may someday be treated as a separate genus.

The specimen with the black background was collected in the National Arboretum, Washington, D.C. for a project that required fresh specimens for dissection. The other was collected on a sticky trap suspended from a weather balloon above the Sahel region of Mali in a project studying mosquito migration.

The mosquito program is funded by the National Institute of Health, and the researchers conducting this study are now collaborating with taxonomists at the USDA and Smithsonian to understand how other groups of insects may be using wind currents for transport to favorable environments.

As meteorology and entomology join forces, we will undoubtedly gain a better understanding of how species travel around the globe and how closely related species came to live so far apart. When next you feel the wind, perhaps take a moment to contemplate insects on the move above you.

Washington Trimorus photographed by Smithsonian intern Coline Bodenreider

Full resolution image: http://specimage.osu.edu/getImageInfo.html?image_id=89036

Malian Trimorus photographed by Smithsonian volunteer Deb Meislin
Full resolution image: http://specimage.osu.edu/getImageInfo.html?image_id=93053

Sceliomorpha

This week features a parasitoid that is also host. The wasp belongs to the genus Sceliomorpha, a creature that has many ancestral, or plesiomorphic, characters that lead systematists to believe it is part of an ancient lineage. At over 5 millimeters long it is a giant in the realm of Platygastroidea, and large enough to become a host for another kind of parasite- mites. This specimen was captured with nearly 10 mites feeding on it internal bodily fluids via mouthparts that penetrate the wasp's exoskeleton.

Like this specimen of Sceliomorpha, you too have mites feeding on you. Numerous species live in your skin- around your eyelashes, on your forehead, on the skin of your back. When next you look in the mirror, perhaps try to view yourself as an ecosystem...

This image was produced from images taken by Smithsonian intern Samantha Fitzsimmons-Schoenberger. The full resolution image may be found here: http://specimage.osu.edu/getImageInfo.html?image_id=93319

Trissolcus japonicus

This week brings a photograph of Trissolcus japonicus emerging from an egg of the brown marmorated stink bug (Halyomorpha halys). As you may know, this invasive species of stink bug is an economically injurious pest on a wide variety of plants and an unwanted invader of human homes. This stink bug has been established on the east coast of the United States for a decade. It is now spreading on the west coast of the US and in Europe where it threatens apples, olives, figs, grapes, and many more delicious fruits and vegetables.

Like the brown marmorated stink bug, T. japonicus, is native to east Asia. It is under study as a biological control agent because it coevolved with the stink bug and it efficiently kills its eggs. Trissolcus japonicus was recently discovered to have become established in the United States on its own (http://jhr.pensoft.net/articles.php?id=4661), almost certainly by hitching a ride in a transport vessel.

Humans so far have been unable to control the stink bug, and it coming years we will see how well T. japonicus succeeds.

This image was produced by Smithsonian intern Annika Salzberg, and the full resolution version may be found here: http://specimage.osu.edu/getImageInfo.html?image_id=86082.

It is a life-like image, but in fact is staged. This female specimen was unable to fully emerge from the egg and died in the position you see here. The eggs were subsequently glued to a leaf for the photograph.

Macroteleia elongata

Macroteleia is a genus that parasitizes grasshopper eggs. Like the eggs from which they emerge, species of Macroteleia are typically elongate creatures, sometimes extremely so, and the genus can often be recognized by eye alone. This species, Macroteleia elongata, was collected in New Hampshire during the summer of 2015 by nature enthusiasts and photographed by a very capable Smithsonian intern, Anthony Cuminale.

The full resolution image (see link below) is an excellent candidate for large format printing.

http://specimage.osu.edu/getImageInfo.html?image_id=91868

Thoron metallicus

This week brings Thoron metallicus, a tenacious parasitoid wasp that parasitizes the eggs of aquatic bugs known as water scorpions (Hemiptera: Nepidae). Water scorpions lay their eggs on aquatic vegetation, but even submerged eggs are not safe from Thoron.

Numerous genera in Platygastroidea are known to parasitize the eggs of aquatic insects and to reach their hosts they are able to use their wings to swim. The following video illustrates two genera, collected in Borneo, that are swimming in the yellow pan traps used to collect these insects:
https://www.youtube.com /watch?v=SCMu8AouuE4.

This photograph was produced by Pei Luo during a Smithsonian internship.