Tag: nature journaling

Dermacentor variabilis

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Ticks are parasitic arachnids of the order Ixodida. They live by feeding on the blood of mammals, birds, and sometimes reptiles and amphibians. They’ve been around for a long time; the oldest known tick fossils are from the Cretaceous period, around 100 million years old.

I’d never heard of the American dog tick (or wood tick) till I brought one home on my neck last weekend. They mostly live east of the Rocky Mountains. Dermacentor variabilis is a three-host tick—the larva, nymph and adult all need to ingest blood.

Some ticks attach to their host rapidly, while others wander around searching for thinner skin, such as that in the ears of mammals. Mine was obviously still on the hunt for a good feeding site. Reading up on tularemia and Rocky Mountain spotted fever, I’m glad I removed it before it latched on!

Pholcus phalangioides

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I thought I’d learn a bit more about our most common spider, the ubiquitous daddy long-legs, also known as the cellar spider. As a synanthrope (an organism that lives near and benefits from humans and their environmental modifications), these spiders can be found on every continent in the world. They prefer the warmth inside human dwellings; daddy long-legs living outdoors can be found in the dimly-lit, calm environment of caves and in between rock crevices.

It takes about one year for these spiders to mature after they are born, and their life span can be two years or more post-maturity.

There is a common misconception that this spider’s venom is extremely dangerous but that their fangs are too short to pierce human skin. Neither statement is true. The fangs are longer (0.25mm) than the epidermis is thick (0.1mm); the venom has a negligible effect on mammals, including humans. So let’s put that urban legend to bed.

Phoca vitulina

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Annette and I drove up the coast a ways to join the Channel Island Nature Journalers for a windswept nature journaling session at Carpinteria. (Note to my Australian friends: the emphasis is on the penultimate syllable, Car-pin-ter-REE-a) A good (blustery) time was had by all.

Alaus oculatus

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There are over 9000 species of click beetles worldwide, and over 900 species in North America alone.

This family is characterized by the unusual click mechanism on the beetle’s underside. A spine on the prosternum can be snapped into a corresponding notch on the mesosternum, producing a violent “click” that can bounce the beetle into the air. Clicking is mainly used to avoid predation, although it is also useful when the beetle is on its back and needs to right itself. See some close-ups and slow motion video here.

Chlaenius aestivus

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We had fun drawing a ground beetle with Trisha this past week, especially as the specimen had mysterious additional mouthparts that our entomologist had never seen before. I didn’t do a great job depicting the metallic red/green head and pronotum. I’d like to get myself some metallic watercolours for times like these.

Tachinidae

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We didn’t identify this fly down to the species, but we figured out the family. Some tachinid flies parasitize pest species, which has allowed them to be used as biological control agents by farmers. For instance, Istocheta aldrichi only attacks the Japanese beetle. But some are generalists; Compsilura concinnata uses at least 200 different hosts, and so is not safe to be used as biological control.

Adult tachinids feed on flowers and nectar from aphids and scale insects. As many species typically feed on pollen, they can be important pollinators of some plants, especially at higher elevations in mountains where bees are relatively few. So don’t be hating on them, just because they’re flies!

Scolopendra polymorpha

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Our most common centipede around here is Scolopendra polymorpha. Their bodies generally reach 4–7 in (10–18 cm) in length, so this one was not a particularly large specimen. They can vary a lot in colour; I loved this guy’s turquoise legs!

Centipedes, including this one, can inflict an intensely painful pinch. They puncture the skin with a powerful pair of modified, hollow, clawed legs called forcipules located on the first body segment, immediately behind the head. Venom glands run through a tube, from inside the head to the tip of each forcipule. The venom may cause an allergic reaction in some people, so best not to pick one up with your bare hands.

Centipedes are carnivorous and nocturnal. They eat silverfish, cockroaches, spiders, crickets, bed bugs and moths, so maybe don’t be too sad if you find one in your house.