Primate Body Lice

This week’s podcast is guaranteed to make your scalp crawl—but don’t worry, it’s most likely all in your head, and not on it. We’ll visit entomologist Richard Pollack to learn about an insect that’s the bane of parents and school principals everywhere—or is it? Ari Daniel Shapiro explains. Photo Credit: Gilles San Martin, CC BY-SA Download a transcript of this podcast read moreDuration: 5:04Published: Wed, 08 Aug 2012 13:52:49 +0000

Hovedhår

Life cycle of the Head Louse (Pediculus humanus capitis), an ectparasite of humansThe life cycle of the Head Louse (Pediculis humanus capitis) has three stages: egg, nymph, and adult. Eggs: Nits are Head Lice eggs. They are hard to see and are often mistaken for dandruff or hair spray droplets. Nits are laid by the adult female and are cemented at the base of the hair shaft nearest the scalp (1). They are 0.8 mm by 0.3 mm, oval and usually yellow to white. Nits take about 1 week to hatch (range 6 to 9 days). Viable eggs are usually located within 6 mm of the scalp. Nymphs: The egg hatches to release a nymph (2). The nit shell then becomes a more visible dull yellow and remains attached to the hair shaft. The nymph looks like an adult head louse, but is about the size of a pinhead. Nymphs mature after three molts (3, 4) and become adults about 7 days after hatching. Adults: The adult louse is about the size of a sesame seed, has 6 legs (each with claws), and is tan to grayish-white (5). In persons with dark hair, the adult louse will appear darker. Females are usually larger than males and can lay up to 8 nits per day. Adult lice can live up to 30 days on a person’s head. To survive , adult lice need to feed on blood several times daily. Without blood meals, the louse will die within 1 to 2 days off the host.From Centers for Disease Control Parasites and Health website.

Female human head louse, Pediculus humanus capitis.Technical settings : - focus stack of 46 images- microscope objective (Nikon achromatic 10x 160/0.25) directly on the body (with adapter ~30 mm)

Pediculus spp.

Country: United Kingdom. Stage: Imago. Identified by: Malcolm Storey. Category: standard photograph or close-up. Photographic equipment used: "35mm transparencies (on a variety of films, but Agfa CT18 in the 1960's to early 1980's followed by Fujichrome in the late 1980's.) Transparencies scanned with Minolta Dimage Scan Dual II AF-2820U transparency scanner.".

Hovedhår

Pediculus spp.

Country: United Kingdom. Stage: Imago. Identified by: Malcolm Storey. Category: standard photograph or close-up. Photographic equipment used: "35mm transparencies (on a variety of films, but Agfa CT18 in the 1960's to early 1980's followed by Fujichrome in the late 1980's.) Transparencies scanned with Minolta Dimage Scan Dual II AF-2820U transparency scanner.".

Hovedhår

Pediculus spp.

Country: United Kingdom. Stage: Imago. Identified by: Malcolm Storey. Category: standard photograph or close-up. Photographic equipment used: "35mm transparencies (on a variety of films, but Agfa CT18 in the 1960's to early 1980's followed by Fujichrome in the late 1980's.) Transparencies scanned with Minolta Dimage Scan Dual II AF-2820U transparency scanner.".

Hovedhår

Pediculus Egg

Hovedhår

Hovedhår

Hovedhår

Hovedhår

From a ventral perspective, and at a low magnification of 151x, this 2006 scanning electron micrograph (SEM) depicted an enlarged view of the chitinous, exoskeletal surface of a female louse, Pediculus humanus var. corporis, in the region where the organism’s forelegs and hean attached to its thoracic region. In this particular view, the exoskeleton seems to be composed of interlocking plates, which is not far from the case, in order to provide flexibility to this patent joint, the chitinous components were arranged in a plate-like manner, attached to one another with thin, by strong layers of exoskeletal chitin. Chitin is a molecule made up of bound units of acetylglucosamine, which is joined in such a way as to allow for increased points at which hydrogen bonding can occur. In this way chitin provides increased strength, and durability as an exoskeletal foundation.Created: 2006

From a ventral perspective, and at a moderate magnification of 307x, this 2006 scanning electron micrograph (SEM) depicted an enlarged view of the chitinous, exoskeletal surface of a female louse, Pediculus humanus var. corporis, in the region where the organism’s forelegs attached to its thoracic region. In this particular view, the exoskeleton seems to be composed of interlocking plates, which is not far from the case, in order to provide flexibility to this patent joint, the chitinous components were arranged in a plate-like manner, attached to one another with thin, by strong layers of exoskeletal chitin. Chitin is a molecule made up of bound units of acetylglucosamine, which is joined in such a way as to allow for increased points at which hydrogen bonding can occur. In this way chitin provides increased strength, and durability as an exoskeletal foundation.Created: 2006

From a ventral perspective, and at a relatively high magnification of 1228x, this 2006 scanning electron micrograph (SEM) depicted an enlarged view of the chitinous, exoskeletal surface of a female louse, Pediculus humanus var. corporis, in the region where the right antennal scape attached to its cephalic region, or head. In this particular view, the exoskeleton seems to be composed of interlocking plates, which is not far from the case, in order to provide flexibility to this patent joint, the chitinous components were arranged in a plate-like manner, attached to one another with thin, by strong layers of exoskeletal chitin. Chitin is a molecule made up of bound units of acetylglucosamine, which is joined in such a way as to allow for increased points at which hydrogen bonding can occur. In this way chitin provides increased strength, and durability as an exoskeletal foundation.Created: 2006

This was one of five scanning electron micrographic (SEM) images (PHIL# 9243 – 9247), successively magnified at higher and higher values, which focused on the head region of a female body louse, Pediculus humanus var. corporis from a ventral perspective. At a high magnification of 1228x, this SEM revealed some of the insect’s exoskeletal morphology exhibited by the cephalic region. Highlighted in this view is the insect’s cone-shaped mouth, which is surrounded by a number of setae, or sensorial hairs, which provide the organism with informational feedback about its environment such as chemistry and temperature.Created: 2006

This was one of five scanning electron micrographic (SEM) images (PHIL# 9243 – 9247), successively magnified at higher and higher values, which focused on the head region of a female body louse, Pediculus humanus var. corporis from a ventral perspective. At a moderate magnification of 307x, this SEM revealed some of the insect’s exoskeletal morphology exhibited by the cephalic region. Note the two partially visible, bilaterally situated antennae composed of three main segments: visible here was the most proximal scape and the pedicle, and not in the field of view, the multi-segmented flagellum. The antennae, and the insect’s body sport sensorial hairs known as "setae, both of which provided the organism with a "picture of its environment, by taking readings in thermal, chemical, and mechanical changes encountered in its immediate surroundings. Its cone-shaped mouth is located at the very top of the image.Created: 2006