About a week ago I posted a spider picture on the Academy’s Facebook page, which I had identified as Ariadna pacifica. After conferring with Darrel Ubick, one of our resident spider experts, I discovered I had misidentified both the family and species! It turns out to be in the family Dictynidae, and is one of about 10 species in the genus Blaboma that are found locally living in leaf litter. They form sheet-like webs which they use mostly as retreats, and are ground hunters of small arthropods. Spiders can be notoriously difficult to identify, so while I may be embarrassed by my mistake, I learned something new that I am not likely to forget!
This week in the Project Lab, I have imaged some unusual looking insects in the family Membracidae. Membracids are a family of true bugs (Hemiptera), which are commonly known as treehoppers and thorn bugs. Membracids live on plants and trees and feed on the sap using their piercing beaks to penetrate the host plant. They are found on all continents except Antarctica, but the tropical varieties attract a lot of attention because they have adapted to look like the plants they live on, by growing projections that often look like the thorns and spines of their host plants. Unlike most insects, they appear to be wingless, though some scientists believe that the “helmet” found on many is actually the result of fused and modified wings. The sharp spines and “thorns” provide both camouflage and protection from hungry predators. Some treehoppers are gregarious, and can be found in groups on the same plant. Sap feeding insects like treehoppers and aphids concentrate the sugars in the sap they consume, and excrete a sweet substance known as honeydew. Because of this, they sometimes form symbiotic relationships with ants, or even iguanas who feed on this substance. Treehoppers do not directly cause harm to humans, although a few of them are pests on agricultural crops. I hope you enjoy the images of these unusual insects.
all images by Vic Smith, copyright CAS 2014
Until next time,
A: Plant habit & inflorescence (including: lower leaf surface zoom of glands & divergence of leaf veins)
C: Dorsal and lateral view of stamens (including: zoom of glands on the connective)
D: Stigma & style
One of my jobs here at the California Academy of Sciences is as Scientific Illustrator. A couple years ago I graduated from a graduate program in Science Illustration from California State University Monterey Bay. Since graduating and completing a couple internships, I now work here illustrating newly discovered or described organisms in various departments. Above is just one botanical plate I’ve completed for my advisor. This species was found in the rainforests of Ecuador, collected a handful of years ago but was just being described last year. Above is the final illustration for one of my advisors here in the Botany Department. When I first receive a new plant to work with, I am given an ancient-looking specimen as seen below:
As botanical illustrator it is my job to essentially revive and reconstruct this plant suitable enough for publication. This plant specimen proved unique in multiple ways to the other Melastomataceae species I have illustrated. The most challenging part of the illustration was reconstructing the entire flower from broken or missing parts. It was also challenging to make the illustration appear more three dimensional, as opposed to flat, with use of perspective and different shading techniques. Below you can see more images of these tiny structures that had to be illustrated for this botanical plate:
Every new plant specimen I work with is pretty exciting. From specimen to specimen you notice how much diversity has developed within and between genera within this plant family. For every plate I concentrate on illustrating every unique characteristic of the species and genus. Some of my later posts will concentrate on the steps from start to finish: preliminary sketches, edits, ink used, type of style used to illustrate various plant parts, and the digital process, etc).
Sean Vidal Edgerton
Botany Department; California Academy of Sciences